U.S. patent number 3,823,805 [Application Number 05/201,403] was granted by the patent office on 1974-07-16 for typewriter controlled by a record medium.
This patent grant is currently assigned to Redactron Corporation. Invention is credited to Edward M. Richards.
| United States Patent |
3,823,805 |
| Richards |
July 16, 1974 |
TYPEWRITER CONTROLLED BY A RECORD MEDIUM
Abstract
Connected to a typewriter controllable by coded combinations of
signals is a source of the combinations to control the operation of
the typewriter. In addition to the usual graphic printing
instructions, signals are generated to automatically vary the line
advances following each carrier return, further signals are
generated to control automatically the occurrences of the carrier
returns, while still further signals control the automatic
underlining or overprinting of graphics, i.e. characters, numerics
and symbols.
|
Inventors: |
Richards; Edward M. (Commack,
NY) |
|
Assignee: |
Redactron Corporation
(Hauppauge, NY)
|
| Family
ID: |
22745678 |
| Appl.
No.: |
05/201,403 |
| Filed: |
November 23, 1971 |
| Current U.S.
Class: |
400/63; 400/252;
400/73 |
| Current CPC
Class: |
B41J
5/42 (20130101) |
| Current International
Class: |
B41J
5/31 (20060101); B41J 5/42 (20060101); B41j
005/30 () |
| Field of
Search: |
;197/19,20,113
;340/172.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pulfrey; Robert E.
Assistant Examiner: Eickholt; Eugene H.
Attorney, Agent or Firm: Hane, Baxley & Spiecens
Claims
What is claimed is:
1. In combination with a typewriter which can print graphics in
response to combination of electric signals and can perform both
start of line and other print formatting movements in response to
particular electrical signalings, apparatus for controlling the
typewriter to controllably perform a start of line positioning
movement comprising alerting means for generating an initiate start
of line print positioning movement signal when the actual print
position of the typewriter is beyond a given distance from the
start of line print position, means for storing coded combinations
of bits representing graphics to be printed and print formatting
movements to be performed wherein a first particular coded
combination of bits is associated with a print formatting movement,
reading means for sequentially reading in a desired order the coded
combinations of bits stored in said storing means, means for
converting the read coded combinations of bits to coded
combinations of signals and electrical signalings for transmission
to the typewriter, examining means connected to said alerting means
for simultaneously examining a given number of sequential coded
combinations of bits in said storing means which will be converted
subsequent to the occurrence of an initiate start of line print
positioning movement signal to determine whether any one of said
given number of sequential coded combination of bits includes said
first particular coded combination of bits, means connected to said
examining means for stopping said reading means when said examining
means indicates the absence of said first particular coded
combination of bits in the group of examined coded combination of
bits, and first particular electrical signal generating means for
transmitting the particular electrical signaling to the typewriter
to perform a start of line positioning movement when said first
particular coded combination of bits representing a start of line
positioning movement is read from said storing means after the
generation of an initiate start of line print positioning movement
signal.
2. The combination of claim 1 further comprising means settable by
further particular coded combinations of bits read from said
storing means for controlling the number of particular electrical
signalings transmitted to the typewriter each time said first
particular electrical signal generating means is activated.
3. In combination with a typewriter which can print graphics in
response to combinations of electric signals and can perform start
of line print positioning movements in response to a particular
electrical signaling, apparatus for controlling the typewriter to
perform automatically different numbers of start of line print
positioning movements comprising means for storing coded
combinations of bits wherein the coded combination of bits
represents graphics to be printed while a first particular coded
combination of bits represents a single start of line print
positioning movement and a second particular coded combination of
bits represents a multiple start of line print positioning
movement, means for sequentially reading in a desired order the
coded combinations of bits stored in said storing means, means for
converting those coded combinations of bits representing graphics
to be printed to combinations of electrical signals for
transmission to the typewriter to cause the printing of graphics,
line advance means for receiving said first and second particular
coded combinations of bits and storing only an indication of the
last received thereof at any given time, means for generating an
initiate start of line print positioning movement signal including
means responsive to a third particular coded combination of bits
read from said storing means, and means receiving said initiate
start of line print positioning movement signal for transmitting a
number of said particular electrical signalings to the typewriter,
said number being determined by the indication stored in said line
advance means.
4. The combination of claim 3 further comprising another means for
generating an initiate start of line print positioning movement
signal when the number of symbols printed by the typewriter since
the previous start of line print position movement by the
typewriter is within a given range.
5. The combination of claim 3 further comprising another means for
generating an initiate start of line print positioning movement
signal when the actual print positiong of the typewriter is beyond
a given distance from the start of line print position.
6. The combination of claim 3 wherein the means for generating an
initiate start of line print positioning movement signal includes
alerting means for generating such signal when the actual print
position of the typewriter is beyond a given distance from the
start of line print position.
7. The combination of claim 6 wherein said storing means stores
third particular coded combinations of bits associated with print
position formatting, and further comprising examining means
connected to said alerting means for examining a given number of
sequential coded combinations of bits in said storing means which
will be converted subsequent to the occurrence of an initiate start
of line print positioning movement signal to determine whether any
one of said given number of sequential coded combination of bits
includes said first particular coded combination of bits, means
connected to said examining means for stopping said reading means
when said examining means indicates the absence of said third
particular coded combination of bits in the group of examined coded
combination of bits, and first particular electrical signal
generating means connected to said examining means for transmitting
the particular electrical signaling to the typewriter to perform a
start of line positioning movement after said third particular
coded combination of bits is read from said storing means.
8. In combination with a typewriter which can print graphics in
response to combinations of electric signals, and which can
backspace in response to a first particular electrical signaling,
apparatus for controlling the typewriter to print composite
graphics having one fixed element and one variable element
comprising means for storing coded combinations of bits
representing the variable elements to be printed, a first
particular coded combination of bits representing a start of
composite printing indicator, and a second particular coded
combination of bits representing an end of composite printing
indicator, means for sequentially reading in a desired order the
coded combinations of bits stored in said storing means, first
controllable means for converting those coded combinations
representing the variable elements to combinations of electric
signals for transmission to the typewriter to cause the printing of
variable elements, second controllable means for generating the
combination of electrical signals representing the fixed element
for transmission to the typewriter for printing the fixed element,
a controlled signal generator for generating said first particular
electrical signaling for transmission to the typewriter for
backspacing, control means having a first state for controlling
only said first controllable means to operate once each time a
coded combination of bits representing a variable element is read,
said control means having a second state for controlling one of
said controllable means, said controlled signal generator and the
other of said controllable means to operate sequentially in that
order each time a coded combination of bits representing a variable
element is read, means, operative during the sequential reading of
the coded combination of bits stored in said storing means, for
sensing for said first particular coded combination of bits for
setting said control means to said first state, and means,
operative during the sequential reading of the coded combination of
bits stored in said storing means, for sensing for said second
particular coded combination of bits for setting said control means
to said second state.
9. The combination of claim 8 wherein the typewriter is also
switchable between upper and lower case positions in response to
second particular signalings and generates a case position
indicating signal in accordance with its instantaneous case
position and said combination further comprising first indicating
means indicating the case of the fixed element, second indicating
means indicating the case of the variable element to be printed,
second control means connected to said first and second indicating
means and receiving the case position indicating signal from the
typewriter and operable when said first control means is in said
second state to select which controllable means operates first in
said sequence.
10. The combination of claim 9 wherein said second control means
includes energizing means for first energizing the controllable
means associated with the element whose case is the same as the
case position of the typewriter when the cases of the fixed and
variable elements are different.
11. The combination of claim 10 further comprising means for
transmitting said second particular signalings to the typewriter to
cause a switch in the case position after the operation of said
energizing means.
12. The combination of claim 8 wherein the typewriter can perform a
space movement in response to a second particular electrical
signaling and further comprising means for controlling the printing
of said fixed element in conjunction with the performance of a
space movement by the typewriter.
13. In combination with a typewriter which can print graphics in
response to combinations of electric signals, which is switchable
between upper and lower case positions in response to first
particular electrical signalings and which can backspace in
response to second particular electrical signaling, and which
generates a case position indicating signal in accordance with its
instantaneous case position, apparatus for controlling the
typewriter to print composite graphics having one fixed element
with a predetermined case and one variable element having either of
the two cases comprising first means for indicating a composite
graphic to be printed, second means for generating the coded
combination of signals representing the fixed element, third means
for generating the coded combination of signals representing the
variable element, first indicating means indicating the case of the
fixed element, second indicating means indicating the case of the
variable element, first control means connected to said first and
second indicating means and receiving the case position indicating
signal from the typewriter for first transferring to the typewriter
the coded combination of signals representing that element whose
case is the same as the case position of the typewriter when the
cases of the two elements are different, and second control means
operative thereafter to control the typewriter to overprint the
other of the two elements.
14. The combination of claim 13 wherein said second control means
comprises third control means, operative after the operation of
said first control means, for controlling the transmission of said
first and second particular signalings to cause the typewriter and
backspace and switch case positions, and fourth control means,
operative after the operation of said third control means, for
controlling the transfer of the coded combination of signals
representing the other element to the typewriter.
15. In combination with a typewriter which can print graphics in
response to combination of electric signals and can perform both
start of line and other print formatting movements in response to
particular electrical signalings, apparatus for controlling the
typewriter to controllably perform a start of line positioning
movement comprising alerting means for generating an initiate start
of line print positioning movement signal when the actual print
position of the typewriter is beyond a given distance from the
start of line print position, storing means for storing coded
combinations of bits representing graphics to be printed and print
formatting movements to be performed wherein a group of first
particular coded combinations of bits are associated with a print
formatting movement, said storing means including a buffer storing
means for storing a plurality of said coded combinations of bits,
reading means for sequentially reading in a desired order the coded
combinations of bits stored in said buffer storing means, means for
converting the read coded combinations of bits to coded
combinations of signal and electrical signalings for transmission
to the typewriter, examining means connected to said alerting means
for examining the sequential coded combinations of bits in said
buffer storing means which will be converted subsequent to the
occurrence of an initiate start of line print positioning movement
signal to determine whether any one of said given number of
sequential coded combination of bits includes one of said first
particular coded combination of bits, means connected to said
examining means for stopping said reading means when said examining
means indicates the absence of one of said first particular coded
combinations of bits in the examined coded combination of bits in
said buffer storing means, and first particular electrical signal
generating means connected to said examining means for transmitting
the particular electrical signaling to the typewriter to perform a
start of line positioning movement when one of said first
particular coded combination of bits is read from said storing
means after the generation of an initiate start of line print
positioning movement signal.
16. The combination of claim 15 wherein one of said first
particular coded combination of bits represents a space positioning
movement.
17. The combination of claim 15 wherein one of said first
particular coded combination of bits represents a hyphen symbol to
be printed by the typewriter.
18. The combination of claim 15 further comprising means settable
by further particular coded combinations of bits read from said
storing means for controlling the number of particular electrical
signalings transmitted to the typewriter each time said first
particular electrical signal generating means is activated.
Description
This invention pertains to automatic typewriters and more
particularly to record medium controlled typewriters.
There is presently available a class of record medium controlled
typewriters which are known as editing typewriters. An editing
typewriter generally comprises a conventional typewriter which has
been modified to communicate via signal paths to an external
device. This modification generally permits the transmission to the
typewriter of signals which perform the same functions within the
typewriter as the stroking of keys by an operator, and the
transmission from the typewriter of signals representing the keys
stroked by an operator.
Within the external devices is a storage medium which can be in the
form of a punched record medium but is preferably in the form of a
magnetic tape or magnetic card. In operation, as an operator
strokes the keys of the typewriter to prepare a hard copy,
representations of the key strokes are recorded on the storage
medium. When the typing is finished there is available the printed
(hard) copy as well as a machine readable version stored in the
storage medium. If one now wishes to edit or correct the text, the
hard copy is so modified and used as a guide for the operator while
the typewriter is driven by the storage medium via the external
device to create a new hard copy and a new machine readable
version. Whenever, the new hard copy reaches a point where a
modification is to be made, the operator stops the storage medium
and manually keystrokes in the modifications and then restarts the
storage medium. In this way, a clean modified hard copy can be
obtained. It should be realized that the above description has been
simplified and that most editing typewriters are quite
sophisticated and at times require considerable interaction with
the operator.
In particular, where the editing is directed to the addition or
deletion of text, it should be apparent that the original ends of
lines of text which were followed by carrier or carriage returns
may no longer be valid. In other words, the character in a stream
of text which occurs at the "right hand" margin may now be
different. Therefore, some provision must be made to provide for
the occurrence of a carrier return at the proper point and even to
include a required hyphenation of characters. A first aspect of the
invention concerns a solution of the problem.
In generating the hard copy, the format often requires changes in
the spacing between lines. In other words, some portions of the
text require single line advancing while others require double line
advancing. Heretofore, such line advancing required the operator to
insert a machine stop code and maintain a log which noted where the
line advancing changed. With such a routine the line advance
selector of the typewriter was set to the initial line advancing
and the playback started. When the stop code was reached the
playback stopped and the operator consulted the log to determine
what the new line advancing should be. The operator set the line
advance selector to the new position and restarted the playback.
Another aspect of the invention concerns the automatic control and
changing of line advancing not requiring the stopping of the
playback or the intervention of the operator.
Quite often, the text requires that certain words or groups of
words should be underlined. Typically present day editing
typewriters perform this routine by typing the word or words,
backspacing to the start of the section to be underlined and then
typing in the underlining. However, it should be apparent that when
the underlined section is broken by carriage or carrier returns,
complications occur. Further, when such text requires modifying,
these complications are magnified. While, in theory, the
above-described routine can be used, it is a fact that operators
are directed to ignore the routine and manually keystroke the
underlining on the final copy. Another aspect of the invention is
directed to apparatus for performing underlining in a way which
avoids such complications.
If one carefully looks at an underlined character or other graphic,
it should be apparent that it is a composite graphic composed of
two unique symbols, one the character symbol and the other the
underline symbol, both printed at the same print position. Present
computer and communications technology often utilizes composite
symbols to expand a font of hard copy graphics. A very common
composite symbol is a character or number symbol on which is
superimposed the slash symbol. One way of generating such composite
symbol is to print the number or character (the variable element),
backspace the typewriter, and then print, say, the slash or
underline (the fixed element). Now, conventional typewriter
keyboards have a limited number of keys. To double the number of
graphics which can be printed, such typewriters are provided with a
case shifting mechanism to shift the printing between upper case
and lower case graphics. Therefore, each key, in effect, controls
the printing of two graphics. When printing composite symbols, it
is possible that the variable and fixed elements have different
cases while the typewriter is resting in one of the case positions.
If the fixed and variable elements are always printed in the same
order, excessive case shifting may be required particularly when
the composite symbols are strings of underlined lower case graphics
since the underline symbol is upper case. Another aspect of the
invention is directed to apparatus for minimizing case
shifting.
The statements of the invention are defined by the appended claims
while the other objects, features and advantages of the invention
will be apparent from the following detailed description of the
invention when read with the accompanying drawing which shows an
exemplary apparatus for realizing the invention.
In the drawing:
FIG. 1 shows a block diagram of a typewriter system according to
the invention;
FIG. 2 shows a logical diagram of the function generator of FIG.
1;
FIG. 3 shows a logic diagram for the shift pulse generator of FIG.
1;
FIG. 4 shows a logic diagram for the cycle generator of FIG. 1;
FIG. 5 shows a logic diagram for the selection magnet drivers of
FIG. 1;
FIG. 6 shows a logic diagram for the operation magnet drivers of
FIG. 1; and
FIG. 7 shows a logic diagram for the margin control of FIG. 1;
The typewriter system to be described by way of example is an
editing typewriter system. It will be assumed, for simplicity, that
the original text of a first draft with editing is stored in a
memory by virtue of an initial operator typing routine and that
this text is to be played back to create a new clean hard copy.
Such a system requires a memory for storing the text, as coded
combinations of bits, means for converting the coded combinations
of bits to electrical signals which either select graphics to be
printed by the typewriter of select operational controls to be
performed by the typewriter, and a typewriter which responds to
such electrical signals. In addition, embedded in the text are
other coded combinations of bits representing operation codes which
control overall operation of the system. Accordingly, the system
also includes control circuits responsive to the operation of "op"
codes to perform the desired control functions.
More particularly, FIG. 1 shows a typewriter system comprising a
storage medium which includes a main memory 10 and a seven
character shift register 12 interacting with a typewriter 13, via
interfacing and control elements comprising a function generator
14, a shift pulse generator 16, a cycle generator 18, the selection
magnet drivers 20, the operational magnet drivers 22 and the margin
control 24.
The main memory 10 can be, for example, a magnetic cassette
recorder wherein the magnetic tape serially stores eight-bit bytes
with the bits in parallel. In addition, the recorder is stepped
forward to transmit on the eight lines of cable MMO the coded
combination of signals representing the next byte of the series
each time a shift data pulse is received on line SD. The shift
register 12 can be a conventional seven-stage shift register
wherein each stage stores the eight bits of a byte. The input IN of
the shift register is connected to the cable MMO and receives the
bytes therefrom in synchronism with the outputting of main memory
10 by virtue of the pulses on line SD connected to the shift input
SH. Shift register 12 has an initial clear input IC connected to
line CLEAR. When a pulse is received at input IC the shift register
is cleared to store all "no op" bytes, a particular coded
combination of bits representing an op code saying no operation is
to be performed. The output of the seventh and last stage of the
shift register 12 is connected to the eight parallel lines MSB, T2,
T1, R5, R4, R2, R1 and LSB. The signals on these lines represent
the eight bits of a byte. The bit on line MSB is used to determine
whether the byte represents an op code. If this bit is a one the
byte is an op code, if it is a zero the byte generally represents
either a graphic or an operation to be performed by the typewriter.
The bit on line LSB indicates the case of a graphic represented by
the byte. If this bit is a one then the graphic is lower case, if a
zero then upper case. The remaining six bits define either op codes
when MSB = 1 or, when MSB = 0, the coded combinations of signals
eventually transmitted to the typewriter for graphic selection. In
addition, the eight outputs of the seventh stage of the the shift
register are collected in an eight line cable SR7 and fed to
function generator 14 and also to margin control 24. In fact, the
eight outputs of each stage of the shift register are fed to margin
control 24, as indicated by eight line cables SR1 to SR7.
While typewriter 13 can take many forms, the system will be
described with respect to the IBM SELECTRIC Input/Output Writer. In
particular, the typewriter receives in parallel signals on lines
DATAC, T2MAG, T1MAG, R5MAG, R4MAG, R2MAG and R1MAG from selection
magnet drivers 20. The receipt of a coded combination of these
signals selects and prints a graphic. In addition, the typewriter
13 receives signals on lines SPMAG, BRMAG, CRMAG, LCMAG and UCMAG
from operational magnet drivers 22. The receipt of a signal from
each of the lines individually causes the typewriter to space,
backspace, carrier return, shift to lower case and shift to upper
case, respectively. The typewriter emits a signal on line KLC when
it is in the lower case shift position, a signal on line KCR while
performing a carrier return and a signal on line BUSYT when the
typewriter is busy performing any of these operations including
printing but not case shifting. Added to the typewriter is a switch
connected to the right margin setting of the typewriter. This
switch causes line MARGIN to emit a signal when the carrier is in
the selected right margin zone. This switch can be considered as an
alerting means for generating an initiate start of line print
positioning movement.
The shift pulse generator 16 primarily generates pulses on line SD
to shift the bytes from memory 10 and through shift register 12 and
on line DOB to operate cycle generator 18. The times of generation
of these pulses is controlled by signals on line NOP from function
generator 14, line STOPA from margin control 24, line BUSYT from
typewriter 13, and line BUSYB from cycle generator 18. The shift
pulse generator 16 includes several manually operable switches
which generate in addition to other signals used internals, signals
on line CHARF, line AUTO and line CLEAR.
Cycle generator 18 primarily controls the number of operation
cycles to be performed and when by the typewriter for each byte
transmitted from the memory and in certain cases, as will
hereinafter become apparent, which operational motions the
typewriter 13 is to perform. Cycle generator 18 generates signals
on lines BUSYB, CYCLA, CYCLB, CYCLC and GCYCLS under control of
signals on line DOB from shift pulse generator 16, on line STOPA
from margin control 24, on line BUSYT from typewriter 13, on lines
PAUL, SLAP, and NOP from function generator 14, and lines GCR1 and
GCR2 from operational magnet drivers 22. Selection magnet drivers
20 primarily receive the six central bits of the bytes from shift
register 12 on lines T2, T1, R5, R4, R2 and R1 and transfer those
bits as signals to typewriter 13 under the control of a signal on
line PROCS from operational magnet drivers 22, a signal on line
BUSYT from typewriter 13 and a signal on line FUNC from function
generator 14. Furthermore, selection magnet drivers 20 can generate
the signals representing an underline symbol or a slash symbol in
response to signals on lines GUL and GSLSH, respectively, from
operational magnet drivers 22.
Operational magnet drivers 22 primarily generate the typewriter
operational control signals transmitted on lines SPMAG, BKMAG,
CRMAG, LCMAG, and UCMAG to control the space, backspace, carrier
return, upper and lower case shift operations, respectively, of
typewriter 13 as well as generating the signals on lines GUL, GSLSH
and PROCS to selection magnet drivers 20, in addition to signals on
lines GCR1 and GCR2 to cycle generator 18. The generation of these
signals is under control of signals on lines KLC, KCR and BUSYT
from typewriter 13, on line LSB from shift register 12, on lines
FUNC, SLAP, PAUL, CONT, SPACE, DCR, HYPHEN, CR and BKSP from
function generator 14, on line LOOK from margin control 24, and
lines CYCLA, CYCLB, CYCLC and GCYCLS from cycle control 18.
Margin control 24 controls the generation of carrier returns when
printing extends into the right hand margin region by generating
signals on lines STOPA and LOOK in response to signals on lines
MARGIN and KCR from typewriter 13, on cables SR1 to SR7 from shift
register 12 and lines AUTO and CHARF from shift pulse generator
16.
Before describing the operation of the system several conventions
should be noted. While all lines, and inputs and outputs connected
thereto, in FIG. 1 are shown carrying one logic condition, in many
cases the line is a pair with the other line carrying the inverse
of that logic condition. Thus, line LSB is actually a pair of lines
LSB and LSB'. Furthermore, with respect to FIGS. 2 to 7, all inputs
are shown connected to the actual line of the pair. However, for
simplicity, in some cases the output connected to the inverse line
of the pair is not shown. Nevertheless, it should be apparent that
any inverse function can be obtained by passing the signal through
an inverter.
In addition, a signal name will be used as a common denominator.
Thus, for example, the LSB signal is carried on line LSB, which is
connected to the LSB output of shift register 12 and the LSB input
of operational magnet drivers 22. Moreover, positive logic will be
used. Therefore, when a signal such as LSB is present, it is "up"
or "high" while its inverse LSB' is absent, "down" or "low", and
when a signal is absent, it's down or low and its inverse present,
up or high.
The operation of the typewriter system will be described by making
reference to FIG. 1. At the start of the operation, it is assumed
that the typewriter 13 is on, is at the left-hand margin and is in
a lower case position, and that the cassette recorder of memory 10
is in the read position, and is at the first byte which will be a
lower case character.
An operator depresses a clear switch CSW and then an automatic
switch ASW in shift pulse generator 16 resulting in the generation
of the CLEAR and AUTO pulse signals plus internally conditioning
pulse generator 16 to operate. The CLEAR signal initializes certain
flip-flops throughout system and most particularly, is fed to the
clear input IC of shift register 12 to force set each stage therein
to store a byte representing a no op code. Function generator 14
decodes the no op code representation on lines SR7 and generates
the NOP signal. The NOP signal is fed to shift pulse generator 16
to make it a free running pulse generator until the NOP signal
terminates. The AUTO pulse signal within pulse generator 16 causes
the generation of a DOB pulse which is fed to cycle generator 18
but it has no effect therein as long as the NOP signal is present.
The DOB pulse signal causes pulse generator 16 to generate an SD
pulse signal which is fed to main memory 10 and to shift register
12 resulting in the reading of the first byte from memory 10 into
stage one of shift register 12 while right shifting by one stage
the contents of shift register 12. Again, the seventh stage
contains a no op code byte and the cycle is repeated. In fact,
there are seven such cycles. After the seventh cycle, stage seven
of shift register contains the first byte on the tape of memory 10,
that byte being a lower case character to be printed which is not a
no op code byte. Accordingly, function generator 14 stops
generating the NOP signal terminating the free-running of pulse
generator 16 and conditioning cycle generator 18 to be responsive
to DOB pulse signals. The last of the free-running DOB pulse
signals occurs just after the termination of the NOP signal and
causes cycle generator 18 to generate a CYCLC signal, by setting
the third stage of the shift register therein, which is fed to
operational magnet drivers 22. In addition, a BUSYB signal is fed
to pulse generator 16. Now, since the byte in stage seven is lower
case, an LSB signal is transmitted to operational magnet drivers
22; and since typewriter 13 is in the lower case position it
transmits a KLC signal to drivers 22. Since the cases agree (are
the same) operational magnet drivers 22 feed a PROCS signal to
selection magnet drivers 20 which have been receiving the six
central or selection bits of the byte in stage seven of shift
register 12. Drivers 20 then transmit a coded combination of seven
signals via lines T2MAG, T1MAG, R5MAG, R4MAG, R2MAG, R1MAG and
DATAC to typewriter. The first six signals correspond to the six
selection bits and select the graphic, while signal DATAC generated
by drivers 20 initiates a print cycle by the typewriter 13. As long
as the pring cycle is present typewriter 13 generates a BUSYT
signal. The leading edge of the BUSYT signal acts as a shift pulse
in the shift register of cycle generator 18 and since the third of
last stage was set it now clears causing the termination of the
CYCLC and BUSYB signals. The termination of the BUSYB signal in
shift pulse generator 16 breaks an interlock which will permit it
to generate another shift pulse in the following manner. The
leading edge of the BUSYT signal causes shift pulse generator 16 to
internally generate a pulse which passes through the now broken
interlock to generate another shift pulse signal SD followed by a
DOB pulse signal. The DOB pulse signal causes the read out of the
next byte and the generation of another CYCLC signal as described
above. The new byte which will be assumed to be an upper case
graphic to be printed is being presented to selection magnet
drivers 20. However, since the typewriter operation is much slower
than the memory transfer the system waits until the end of
typewriter operation as indicated by the termination of the BUSYT
signal. The absence of this signal in operational magnetic drivers
22 permits the generation of a PROCS signal in response to the
CYCLC signal to initiate a new print cycle as described above and
such a cycle would begin as long as the cases agree. However, it
should be recalled that this second byte was an upper case graphic.
Therefore, the LSB signal is absent. But typewriter 13 is in the
lower case position and generating the KLC signal. The presence of
the KLC signal and the absence of the LSB signal indicating
disagreement and that the next graphic is upper case causes
operational magnet drivers 22 to transmit an UCMAG signal to
typewriter 13 which shifts to the upper case position in response
thereto. After this case shift the KLC signal disappears. The cases
now agree and the PROCS signal is generated.
In a similar way if the LSB signal were present indicating a lower
case graphic and the KLC signal were absent indicating an upper
case position of the typewriter 13, operational magnet drivers 22
would transmit an LCMAG signal to typewriter 13 causing a shift to
the lower case position and the generation of the KLC. Then both
KLC and LSB are present indicating that the cases agree, and such
agreement permits the generation of the PROCS signal in response to
the CYCLC signal. Note that case shifting does not cause the
generation of a BUSYT signal by the typewriter.
The next operation to be described is the generation of a composite
graphic. Two examples will be given, one is a slashed symbol and
the other is an underlined symbol. In each case there are three
steps to the operation. There are two print cycles and one
backspace cycle so that both elements of the composite graphic are
printed in the same space, i.e., one is "superimposed" on the
other. The order in which the elements are printed is a function of
the cases involved. Case shifing can be minimized when the cases of
the two elements disagree. Then, the element having the same case
as the present case position of the typewriter is printed
first.
First it will be assumed that the composite graphic is a slashed
symbol to be printed. Now the slash element is a lower case graphic
while the slashed graphic can be either depending on the case of
the symbol to be slashed. A slashed graphic is indicated by the MSB
bit equal to one with the case of the position to be determined as
usual by the value of the LSB bit. Usually, such composite graphics
are not printed but to print such a graphic, the operator depresses
the print switch PSW in the function generator.
When the byte representing a slashed graphic is in stage seven of
the shift register 12, function generator 14 senses that the MSB
signal is present and generates a SLAP signal which is fed
primarily to cycle generator 18 and operational magnet drivers 22.
Cycle generator 18 in response thereto causes the generation of a
GCYCLS signal and sets the three stage shift register to its first
stage resulting in the generator of the CYCLA signal which, in
turn, causes the generation of the BUSYB signal. The presence of
the BUSYB signal in shift pulse generator 16 halts any further
generation of SD shift pulse signal. Now, either the slash or the
symbol is printed first. If the symbol is upper case and the
typewriter is in the upper case position (the upper cases agree)
the symbol will be printed first otherwise the slash will be
printed first.
It will first be assumed that the upper cases agree. Therefore, the
symbol is printed first. The coincidence of the absence of the KLC
signal, the absence of the LSB signal and the presence of the SLAP
signal result in the generation of the PROCS signal by operational
magnet drivers 22 and the symbol is printed as described above. The
print cycle causes the usual generation of the BUSYT signal by
typewriter which steps the shift register in cycle generator 18 to
stage two terminating signal CYCLA and initiating signal CYCLB.
However, if the symbol were not to be printed first because there
was not upper case agreement then the slash would be printed first.
However, depending on the case position of the typewriter a case
shift may be necessary because the slash is a lower case symbol.
There are two possibilities. First, if the typewriter is in lower
case then the coincidence of the presence of the KLC signal, the
presence of the CYCLA signal and the presence of the SLAP signal
causes operational magnet drivers 22 to transmit a GSLH signal to
selection magnet drivers 20. In response to this signal magnet
drivers 20 transmit the proper coded combination of signals to
typewriter 13 to select the slash symbol and initiate a print cycle
with the generation of the usual BUSYT signal which steps the shift
register in cycle generator 18 to the second stage with generation
of the CYCLB signal. Second, if the typewriter had been in the
upper case position, then it must be shifted to lower case before
printing the slash. The coincidence of the absence of the KLC
signal, the presence of the CYCLA and the presence of the SLAP
signal in operational magnet drivers 22 causes the transmission of
the LCMAG signal to typewriter 13 which switches to lower case and
starts generating the KLC signal. Now, there is lower case
agreement and the routine continues according to the above
described first possibility resulting in the printing of the slash
and the stepping of the shift register in cycle generator 18 to the
second stage with the generation of the CYCLB signal.
For any of the above described conditions, it is seen that the
CYCLA cycle results in the printing of either the slash or the
symbol and the stepping to the CYCLB cycle. AT the end of this
print cycle the coincidence of the absence of the BUSYT signal and
the presence of the CYCLB signal causes operational magnet drivers
22 to transmit a BKMAG signal to typewriter 13. In response
thereto, the typewriter backspaces and generates the usual BUSYT
signal which steps the shift register in cycle generator 18 to the
third stage to cause the termination of the CYCLB signal and the
initiation of the CYCLC signal. Now, if the slash had been printed
first it is now necessary to print the symbol. From this point the
situation is the same as the usual printing of an unslashed graphic
in cycle CYCLC. Hence, the description will not be repeated except
to say that the onset of the BUSYT signal clears the shift register
in cycle generator 18 resulting in the termination of the CYCLC and
BUSYB signals.
However, if the symbol had been printed first, it is now necessary
to print the slash. It should be recalled that to print the symbol
first at least the typewriter was in the upper case position. Since
the slash symbol is lower case, there must be a down shifting to
lower case. The coincidence of the absence of the KLC signal, the
presence of the SLAP signal and the presence of the CYCLC signals
causes operational magnet drivers 22 to generate an LCMAG signal.
The receipt of this signal causes typewriter 13 to shift to the
lower case position and the generation of the KLC signal. The
coincidence of the presence of the KLC signal, the presence of the
CYCLC and the presence of the SLAP signals cause the transmission
of the GSLSH signal to selection magnet drivers 20. The slash is
printed as described above and the BUSYT signal is generated which
clears the shift register in cycle generator 18 resulting in the
termination of the CYCLC and BUSYB signals.
For all conditions the termination of the BUSYB signal breaks the
interlock in shift pulse generator 16 so that when the BUSYT signal
terminates, shift pulse generator 16 generates the SD and DOB pulse
signals reading a new byte out for processing. Unless the new byte
in stage seven of shift register 12 is a slashed graphic the SLAP
signal terminates.
Whereas the slashed graphic operation occurred on a signal graphic
basis with the graphic byte itself controlling the generation of
the composite graphic, the underline routine is a block operation.
In particular, a first op code byte indicates that all succeeding
bytes representing graphics are to be underlined until a second op
code byte indicates the end of the underlining. The first op code
can have one of two values, one associated with continuous
underline wherein all positions with the exception of operations
such as carrier return, are underlined and the other associated
with word underline wherein space positions are also not
underlined.
Word underlining will be described first. When the op code for word
underlining is in stage seven of shift register 12, function
generator 14 starts generating a WORD signal used internally and a
NOP signal which is fed to shift pulse generator 16 to cause the
generation of another SD and another DOB pulse signal. If the new
byte shifted in stage seven is valid for underlining, the function
generator 14 in response to the WORD signal and to this byte
generates a PAUL signal. Now, effectively, the PAUL signal assumes
the same role that the SLAP signal performed in generating slashed
graphics. The routines are generally the same with a major
difference being that the underline symbol is upper case.
Therefore, the PAUL signal cooperating with the DOB pulse signal
sets the shift register in cycle generator 18 to the first stage
causing the generation of the CYCLA, GCYCLS and BUSYB signals as
described above. The BUSYB signal in shift pulse generator 16
temporarily terminates further generation of the SD and DOB pulse
signals. Now, either the underline of the symbol is printed first.
If the symbol is lower case and the typewriter is in the lower case
position (the lower cases agree) the symbol is printed first
otherwise the underline which is an upper case symbol will be
printed first.
It will be first assumed that the lower cases agree. Therefore, the
symbol is printed first. The coincidence of the presence of the KLC
signal, the presence of the LSB signal and the presence of the PAUL
signal result in the generation of the PROCS signal by operational
magnet drivers and the symbol is printed as described above. The
print cycle causes the usual generation of the BUSYT signal by
typewriter 13 which steps the shift register in cycle generator 18
to stage two terminating the CYCLA signal and initiating the CYCLB
signal.
However, if there were not lower case agreement the underline is
printed first. Two possibilities then arise. First, if the
typewriter is in upper case, then the coincidence of the absence of
the KLC signal, the presence of the CYCLA signal and the presence
of the PAUL signal causes operational magnet drivers 22 to transmit
a GUL signal to selection magnet drivers 20. In response to this
signal magnet drivers 20 transmit the proper coded combination of
signals to typewriter 13 to select the underline symbol and
initiate a print cycle with the generation of the usual BUSYT
signal which steps the shift register in cycle generator 18 to
stage two with the generation of the CYCLB signal. Second, if the
typewriter had been in the lower case position, then it must be
shifted to upper case before printing the underline. The
coincidence of the presence of the CYCLA, PAUL and KLC signals
causes the transmission of the UCMAG signal to the typewriter which
switches to upper case and terminates the KLC signal. Now there is
upper case agreement and the routine continues according to the
above-described first possibility which ends with the generation of
the CYCLB signal.
At the end of this first print cycle, the coincidence of the
absence of the BUSYT signal and the presence of the CYCLB signal
causes operational magnet drivers 22 to transmit a BKMAG signal to
typewriter 13. In response thereto, the typewriter backspaces and
generates the usual BUSYT signal stepping the shift register in
cycle generator 18 to the third stage which terminates signal CYCLB
and initiates signal CYCLC. If the underline had been printed first
the symbol must now be printed. In such a case the situation is the
same as printing any non-underlined graphic in cycle CYCLC.
Therefore, the description will not be repeated except to say that
the onset of the BUSYT signal clears the shift register in cycle
generator 18 resulting in the termination of the CYCLC and BUSYB
signals.
However, if the symbol were printed first, it is now necessary to
print the underline. If the symbol were printed first, the
typewriter was in the lower case position. Since the underline is
upper case, there must be a shift to upper case before the printing
of the underline. The coincidence of the presence of the KLC, PAUL,
and CYCLC signals causes operational magnet drivers 22 to generate
a UCMAG signal. The receipt of this signal by typewriter causes a
shift to upper case and the termination of the KLC signal. The
coincidence of the absence of the KLC signal and the presence of
the PAUL and CYCLC signals causes the transmission of the GUL
signal to selection magnet drivers 20. The underline is printed as
described above and the BUSYT signal is generated which clears the
shift register in cycle generator 18 resulting in the termination
of the CYCLC and BUSYB signals.
For all conditions the termination of the BUSYB signal breaks the
interlock in shift pulse generator 16 so that when the BUSYT signal
ends, shift pulse generator 16 generates the SD and DOB pulse
signals reading a new byte for processing.
If the byte had represented a space operation, function generator
14 would have generated a SPACE signal. The SPACE signal fed to
operational magnet drivers 22 would result in the generation of a
SPMAG signal fed to typewriter 13. The typewriter would space and
generate the usual BUSYT signal.
If the underlining were to be continuous the op code for continuous
underline would have been detected and the CONT instead of the WORD
signal would be generated in function generator 14. The CONT signal
would cause the generation of the PAUL signal so the underlining
operations are the same except that the CONT signal is also fed to
operational magnet drivers 22. Therefore, when a SPACE signal is
detected during the CYCLC cycle, a GUL signal is generated so that
the space is simply underlined. However, as will hereinafter be
apparent, automatic carrier turn operations from the right margin
can use a space op code to generate a carrier return. Therefore, to
prevent an underlining from being performed in such a case the
following provision is made. When the carrier is in the right
margin region the typewriter 13 generates a MARGIN signal. Margin
control 24 in response thereto transmits a LOOK signal to
operational magnet drivers 22 to prevent an underline of a space
under these conditions.
Underlining continues until the byte in stage seven of shift
register 12 represents an end of underline control. Function
generator 14 detects this byte and terminates either the WORD or
CONT signal while generating a NOP signal. When the WORD or CONT
signal terminates underlining is over while the NOP signal permits
the accessing of the next byte for processing.
The carrier return operations will not be described. There are two
carrier return operations. One results in a carrier return to the
left margin and a single line advance (a single start of line print
positioning movement), the other results in a carrier return to the
left margin with a double line advance (a double or multiple start
of line print positioning movement). In addition, there are two
ways in initiating either carrier return operation. One is by the
reading of a carrier return op code from the memory, the other by
sensing when the carrier is within the righthand margin region.
Whether a single or double line advance is to be performed is
determined by reading op code bytes associated therewith from the
memory. There is a special op code byte associated with single line
advance and another op code byte associated with double line
advance. When one of these special op code bytes is read, all
subsequent carrier returns will also perform the line advance
associated with that op code byte until the other special op code
byte is read.
The first function to be described will be the generation of the
control signal indicating the number of line advances per carrier
return.
When an op code byte representing a double line advance is in stage
seven of shift register 12, function generator 14 detects this byte
and sets a flip-flop which starts generating a DCR signal which is
transmitted to operational magnet drivers 22. This DCR signal will
remain present until the op code byte representing a single line
advance is in stage seven of shift register 12. At that time,
function generator 14 detects that op code byte and resets the
flip-flop terminating the DCR signal. Whenever either of these op
code bytes is in stage seven function generator 14 also transmits a
NOP signal to shift pulse generator 16 to permit the generation of
another SD pulse signal and another DOB pulse signal so that the
next byte can shifted into stage seven of shift register 12.
Now, assume that the last read line advance op code byte whenever
it occurred was for single line advance and that the byte in stage
seven of shift register 12 is a carrier return op code byte.
Therefore, function decoder 14 is not generating the DCR signal.
However, the function decoder 14 decodes the carrier return op code
and generates and transmits the FUNC signal and CR signal to
operational magnet drivers 22. In addition, the DOB pulse signal
associated with the shifting of the carrier return op code byte
into position sets the third stage of the shift register in cycle
generator 18 causing the generation of the CYCLC and BUSYB signals.
The BUSYB signal sets the interlock in shift pulse generator 16
while, effectively, the coincidence of the presence of the CYCLC,
FUNC and CR signals causes operational magnet drivers 22 to
transmit a CRMAG signal to typewriter 13. In response thereto,
typewriter 13 starts the carrier return action and generates a KCR
signal indicating a carrier return is being performed and generates
the usual BUSYT signal. The KCR signal is fed to operational magnet
drivers 22 but has no effect at this time. The BUSYT signal clears
the shift register in cycle generator 18 and terminates the CYCLC
signal and BUSYB signal breaking the interlock in shift pulse
generator 16. The BUSYT signal also triggers shift pulse generator
16 to generate another SD pulse signal and another DOB pulse signal
to make the next byte available.
Had the DCR signal been present indicating a double line advance
the operation would have been the same up to the transmission of
the KCR signal by the typewriter 13 during the carrier return. Then
the coincidence of the presence of the KCR and DCR signals in
operational magnet drivers 22 causes the setting of a flip-flop.
The flip-flop starts generating a GCR2 signal that is fed to cycle
generator 16 to sustain the generation of the BUSYB signals as long
as the GCR2 signal is present in spite of the fact that BUSYT
signal terminates the CYCLC signal. At the end of the BUSYT signal,
the coincidence of the presence of the GCR2 signal and the absence
of the BUSYT signal causes operational magnet drivers 22 to
transmit another CRMAG signal to typewriter 13. In response
thereto, typewriter 13 performs the second carrier return and
generates another BUSYT signal. This BUSYT signal resets the
flip-flop terminating the GCR2 signal which terminates the BUSYB
signal so that shift pulse generator 16 can generate the next SD
and DOB pulse signals to make the next byte available for
processing.
Now, an automatic or typewriter controlled carrier return routine
will be described. As the graphics are being printed the carrier
moves from the left-hand margin toward the right-hand margin. When
the carrier enters the right-hand margin zone a switch is actuated
which will remain actuated as long as the carrier is in a region of
at least seven print positions. The actuation of the switch causes
the transmission of a MARGIN signal by typewriter 13 to margin
control 24. Margin control 24 tests to see whether anyone of the
next seven upcoming bytes, i.e., the bytes stored in shift register
12 are possible line end bytes. A line end is a byte representing a
carrier return, a byte representing a space or a byte representing
a hyphen. If such a byte is stored in shift register 12, byte
processing continues until such byte is in the seventh stage. If
such a byte is not present there is a need for operator
intervention. The first situation will be described first. The
MARGIN signal causes the setting of a flip-flop in margin control
24 which transmits a LOOK signal to operational magnet drivers 22.
Now, three possibilities arise, the byte is (1) a carrier return op
code byte, (2) a space op code byte or (3) a hyphen op code byte.
For possibility 1, when the op code carrier return byte reaches the
seventh stage of shift register 12 it is processed as any normal
carrier return op code byte and when the carrier moves toward the
left-hand margin the KCR signal generated by the typewriter is fed
to margin control 24 and resets the flip-flop terminating the LOOK
signal. If the byte were a space op code byte, then when this byte
reaches the seventh stage of shift register 12 function generator
14 transmits the SPACE signal to operational magnet drivers 22. The
coincidence of the LOOK and SPACE signals therein prevents the
usual processing of a space operation but instead causes the
transmission of a CRMAG to typewriter 13 which initiates a carrier
return and the process continues as if the op code byte had called
for a carrier return, i.e., according to possibility 1. Now, if the
space op code occurred in a continuous underlining string, the LOOK
signal in operational magnet drivers 22 would prevent the
generation of the underline. If the op code byte were a hyphen,
i.e., possibility 3, it is necessary to print the hyphen and then
generate the carrier return. Thus, when the hyphen op code byte
reaches stage seven of shift register 12, function generator 14
generates the HYPHEN signal and the hyphen symbol is printed as
usual. When the usual BUSYT signal is generated, the coincidence of
the BUSYT, LOOK and HYPHEN signals set a flip-flop in operational
magnet drivers 22 which starts generating a GCR1 signal. The GCR2
signal is transmitted to cycle generator 18 to keep the BUSYB
signal present regardless of the state of the CYCLC signal. When
the BUSYT signal terminates at the end of the hyphen print cycle,
the GCR1 signal causes operational magnet drivers 22 to transmit a
CRMAG signal to typewriter 13 and the process continues as with any
other carrier return process except the BUSYT signal resets the
flip-flop that had been set in operational magnet drivers 22 to
terminate the GCR1 signal.
Now, assume that none of the bytes in shift register 12 represented
an end of line byte and that therefore the operator must intervene
to hyphenate the word in progress and manually generate the carrier
return. The LOOK signal interval to the margin control 24 then
causes the generation of a STOPA signal which is transmitted to
shift pulse generator 16 to reset the flip-flop therein which had
been generating a RUN signal and the automatic generation of the SD
and DoB pulse signals terminates. The STOPA signal is also fed to
cycle generator 18 to prevent the automatic setting of the stages
of the shift register therein. Now, the bytes are transferred from
memory 10 under the control of the operator. The operator depresses
and releases the switch OCSW in shift pulse generator 16
momentarily generating a CHAR signal which sets a flip-flop which
generates a CHARF signal. In response to the generation of the CHAR
signal, shift pulse generator 16 generates one DOB pulse signal and
one byte is processed and the BUSYT signal causes the generation of
an SD pulse signal making the next byte available. To process this
next byte the operator must again depress the switch OCSW. This
continues until the operator finds a convenient position to
manually insert a hyphen, via the keyboard of the typewriter and
then to manually insert, via the keyboard of the typewriter, a
carrier return driving the carrier to the left-hand margin. Then,
the operator depresses and releases the automatic switch ASW in
shift pulse generator 16 to generate an AUTO pulse signal. The AUTO
pulse signal interval to shift pulse generator 16 causes the
generation of the DOB and SD pulse signals while the AUTO pulse
signal received by margin control 24 resets the flip-flop which was
set by the MARGIN signal to terminate the LOOK and STOPA
signals.
Finally, the system can be stopped by the operator depressing a
stop switch SSW in shift pulse generator 16.
The function generator 14 is shown in FIG. 2 comprising decoders
201 to 212 each having inputs connected to the lines of cable SR7.
Each decoder decodes a unique coded combination of the bits of the
byte on the lines of cable SR7 to generate a signal representing
the byte. The bytes decoded by each decoder are indicated by the
labeling of the box representing the decoder.
Furthermore, the decoders 205, 206 and 207 are associated with
underlining processes which are generally multibyte processes and
therefore, require some memory function. Accordingly, set-reset
flip-flops 213 and 214 are provided. The output of word underline
decoder 205 is connected to the set input S of flip-flop 213 and
the output of continuous underline decoder 206 is connected to set
input S of flip-flop 214. The output of end underline decoder 207
is connected to the reset inputs R of both flip-flops while the
CLEAR signal line feeds the clear inputs of both flip-flops to
force reset them at the start of operation of the system. The
output 1 of flip-flop 213 is connected to the WORD signal line and
the output 1 of flip-flop 214 is connected to the CONT signal
line.
OR-circuit 218 which transmits the NOP signal has one input
connected to the output of NO OP decoder 209 and a second input
connected to the output of AND-circuit 216 whose inputs are
connected to the output of slash decoder 208 and the inverting
output of manually operable print switch PSW. Thus, if either a no
op code byte is sensed for a slashed byte which is not to be
printed is detected the NOP signal is generated to prevent
processing of the byte and to give an immediate stepping to the
next byte. The output of AND-circuit 215 is connected to the SLAP
signal line while its inputs are connected to the output of slash
decoder 208 and the direct output of print switch PSW so that when
a detected slashed byte is to be printed the SLAP signal is
generated.
The output of AND-circuit 219 is connected to line PAUL while its
inputs are connected to the output of under-lineable character
decoder 210 and to the output of OR-circuit 220 whose inputs are
connected to the WORD and CONT signal lines. There is a signal on
line PAUL when underlining is called for as indicated by either the
WORD or CONT signals provided the byte is underlineable, i.e., not
a carrier return or backspace operation, for example.
Set/reset flip-flop 221 having its output 1 connected to line DCR
remembers whether there is to be single or double line advances.
The set input S of flip-flop 221 is connected to the output of
double advance decoder 212 while the reset input R is connected to
the output of single line advance decoder 211.
Finally, the output of OR-circuit 222 is connected to the FUNC line
while its inputs are connected to the SPACE, BKSP and CR signal
lines.
Shift pulse generator 16 shown in FIG. 3 centers around the
circuits for generating the SD pulse signals for shifting bytes out
of the memory and the DOB pulse signals for initiating processing
of such bytes.
Normally, the onset of a BUSYT signal at the input of one shot
multivibrator 301 causes it to transmit a pulse to one shot
multivibrator 302 which is triggered by the trailing edge of such
pulse to transmit a pulse to one input of AND-circuit 303. The
second input of AND-circuit 303 receives the BUSYB' signal. This is
the interlock which prevents byte shifting for the memory as long
as the previous byte is being processed. The output of AND-circuit
303 is connected to one input of OR-circuit 304 whose output is
connected via inverter 305 to the input of one shot multivibrator
306. Thus, when the pulse from one shot multivibrator 302 passes
through AND-circuit 303 it triggers one shot multivibrator which
transmits from its positive output a pulse to line SD. The trailing
edge of this pulse triggers one shot multivibrator 307 since the
negative output of one shot multivibrator 306 is connected to the
input of one shot multivibrator 307. The output of one shot
multivibrator 307 is connected to one input of AND-circuit 308
whose other input is connected to the RUN signal line. If the RUN
signal is present which is the usual case, one shot multivibrator
307 triggers one shot multivibrator 311 since the output of
AND-circuit 308 is connected to one input of OR-circuit 309 whose
output is connected via inverter 310 to the input of one shot
multivibrator 311. The output of one shot multivibrator 311 is
connected to the DOB signal line so that whenever this one shot
multivibrator is triggered a DOB pulse signal is generated for
initiating processing of the available byte.
The RUN signal is generated by set/reset flip-flop 312 whose output
1 is connected to line RUN. The set input S of the flip-flop 312 is
connected to manually operable auto switch ASW which effectively
generates a pulse whenever depressed. The reset input R of
flip-flop 312 is connected to the output of three-input OR-circuit
314. The first input thereof is connected to stop switch SSW which
can be similar to auto switch ASW. The second input thereof is
connected to line CLEAR which is connected to the output of initial
clear switch CSW which can be similar to auto switch ASW. The third
input thereof is connected to the output of AND-circuit 315 whose
inputs are connected to the STOPA, DOB and NOP' signal lines to
stop automatic pulse generation when the operator must manually end
a line of text through the assistance of the one character switch
OCSW.
One character switch OCSW which can be similar to auto switch ASW
has its output connected to line CHAR which is connected to the set
input S of set/reset flip-flop 316 and to a second input of
OR-circuit 309. The reset input of flip-flop 316 is connected to
the line SD while its outputs 1 and 0 are connected to the CHARF
and CHARF' signal lines, respectively. Note each time switch OCSW
is depressed a CHAR pulse signal is generated which results in the
generation of a DOB pulse signal. The third input of OR-circuit 309
is connected via line AUTO to the output of auto switch ASW to
initiate the processing of the first available byte when the system
is started or restarted.
Since no op code bytes are not processed by the typewriter 13 and
normal generation of the SD pulse signals is initiated by the BUSYT
signal from the typewriter it is necessary to provide an alternate
path. This is performed by the AND-circuit 317 having inputs
connected to the NOP and DOB signal lines and an output connected
to the second input of OR-circuit 304.
Cycle generator 18 shown in FIG. 4 centers around three stage shift
register 401 comprising stages 401-1, 401-2 and 401-3. Shifting is
from stage 401-1 to stage 401-2 to stage 401-3 in response to shift
pulses received at the shift input SH connected to the BUSYT signal
line. The shift register is open ended, i.e., when stage 401-3 is
set the next shift pulse clears the register. The register can also
be cleared by a pulse signal on line CLEAR connected to the IC
input. Shift register 401 is loaded by either setting stage 401-1
by feeding a pulse into set input S1 which is connected to the
output of AND-circuit 402, or by setting stage 401-3 by feeding a
pulse into set input S3 which is connected to the output of
AND-circuit 403.
The inputs of AND-circuit 402 are connected to the STOPA' signal
line, the DOB signal line and the output of OR-circuit 404 whose
inputs are connected to the SLAP and PAUL signal lines. Thus, it
should be apparent that stage 401-1 is set to generate the CYCLA
signal at its output only when composite graphics are to be
printed. The inputs of AND-circuit 403 are connected to the STOPA',
DOB, NOP' and GCYCLS' signal lines. Note the GCYCLS' signal line is
connected to the output of inverter 405 whose input is connected to
the output of OR-circuit 404. Stage 401-3 is set and generates the
CYCLC signal during the processing of non-composite graphics. The
output of stage 401-2 is connected to line CYCLB and transmits a
signal thereon when set to initiate typewriter backspacing.
The interlock signal BUSYB' is generated by inverter 406 having an
input connected to the output of OR-circuit 407 whose inputs are
connected to the CYCLA, CYCLB, CYCLC, GCR1 and GCR2 signal lines.
If any one of these signals is present the BUSYB signal is absent
and the BUSYB' signal present. If none of these signals are present
the reverse is true.
Selection magnet drivers 20 shown in FIG. 5 generate the coded
combinations of signals fed to the typewriter to select the graphic
to be printed. Generally, the graphic is selected according to the
coded combination of selection bits of the available byte as
represented by the T2, T1, R5, R4, R2 and R1 signals from shift
register 12. Each one of these signals is connected to an input of
the two-input AND-circuits 501, 502, 503, 504, 505 and 506,
respectively. The second input of each of these AND-circuits is
connected to the output of AND-circuit 507 whose inputs are
connected to the BUSYT', FUNC' and PROCS signal lines. The output
of AND-circuit 507 controls when the graphic should be selected.
Whenever the selected graphic is to be printed a DATAC signal is
generated in parallel with the coded combination of selection
signals. The DATAC signal is generated by OR-circuit 508 which also
has an input connected to the output of AND-circuit 507. It will be
recalled that when composite graphics are to be printed, it is
necessary to generate the slash or underline symbol. The selection
signals for the slash signal are derived from the GSLH signal which
is fed to a second input of OR-circuit 508 and to an input of each
of the two input AND-gates 509 and 510 whose second inputs receive
the BUSYT' signal. The underline symbol is selected by merely
generating a DATAC signal, therefore the GUL signal is fed to the
third input of OR-circuit 508. Finally, the outputs of AND-circuits
509 and 503 are connected to inputs of OR-circuit 511 whose output
is connected to line R5MAG, and the outputs of AND-circuits 506 and
510 are connected to inputs of OR-circuit 512 whose output is
connected to line R1MAG. The outputs of AND-circuits 501, 502, 504
and 505 ae connected respectively to lines T2MAG, T1MAG, R4MAG and
R2MAG, respectively. It should be noted that lines DATAC, T2MAG,
T1MAG, R5MAG, R4MAG, R2MAG, and R1MAG are preferably connected to
power amplifiers and level shifters (not shown) which are known to
those skilled in the art.
Operational magnetic drivers 22 shown in FIG. 6 consists of two
circuits; one associated with carrier return operations and the
other associated with backspacing, spacing, printing and case
shifting operations. The carrier return circuits controllably
generate a signal on line CRMAG connected to the output of
AND-circuit 601 having one input connected to line BUSYT' and a
second input connected to the output of OR-circuit 602. The inputs
of OR-circuit 602 are connected, respectively, to the output of
AND-circuit 603, the output of AND-circuit 604, the GCR1 signal
line and the GCR2 signal line.
The inputs of AND-circuit 603 are connected to the SPACE, LOOK and
CYCLC signal lines so that a carrier return can be initiated when a
space byte is available during the right margine routine. The
inputs of AND-circuit 604 are connected to the PROCS and CR signal
lines so that a carrier return can be initiated whenever a carrier
return byte is available.
The output 1 of edge triggered flip-flop 605 is connected to line
GCR1 while the data input D thereof is connected to the output of
AND-circuit 606. The inputs of AND-circuit 606 are connected to
lines LOOK and HYPHEN so that a carrier return can be initiated
when a hyphen byte is available during the right margin routine.
The BUSYT signal is fed to the clock terminal C of flip-flop
605.
The output of flip-flop 606 is connected to line GCR2. The data
input D of flip-flop 606 is connected to the output of AND-circuit
607 whose inputs are connected to lines DCR and KCR and the output
0 of flip-flop 606 to initiate the second carrier return when
double line advance is called for. The BUSYT signal is fed to clock
terminal C of flip-flop 606.
The second circuit of operational magnet drivers 22 centers around
logic network 608 which generates the BKMAG, SPMAG, PROCS, LCMAG,
UCMAG, GSLSH and GUL signals. The logic network 608 is an array of
AND-circuits, OR-circuits and inverters which perform the following
Boolean operations:
1. BKMAG = CYCLB .sup.. BUSYT' + BKSP .sup.. PROCS
2. spmag = procs .sup.. space
3. lcmag = [busyt'] .sup.. [(agree'.sup.. a.sup.. lsb) + (b.sup..
klc')]
4. ucmag = [busyt'] .sup.. [(agree'.sup.. a.sup.. lsb') + (c.sup..
kLC)]
5. gslsh = b.sup.. klc.sup.. busyt'
6. gul = c.sup.. klc'.sup.. busyt'
7. procs = a.sup.. agree.sup.. busyt'
8. agree = (func) + (klc.sup.. lsb) + (klc'.sup.. lsb')
9. pfrst = (slap.sup.. upper.sup.. lsb') + (paul.sup.. lower.sup..
lsb)
10. a = [pfrst.sup.. cycla] + [cyclc.sup.. gcycls.sup.. pfrst'] +
[gcycls.sup.. cyclc.sup.. (cont.sup.. space)'.sup.. (space.sup..
look)']
11. b = (pfrst.sup.. cyclc.sup.. slap) + (pfrst'.sup.. cycla.sup..
slap)
12. c = (pfrst.sup.. cyclc.sup.. paul) + (pfrst'.sup.. cycla paul)
+ (cyclc.sup.. look'.sup.. cont.sup.. space),
where a (+) implies an OR-function which can be performed by an
OR-circuit, a (.sup..) implies an AND-function which can be
performed by an AND-circuit and (') implies a NOT-function which
can be performed by an inverter.
The UPPER and LOWER signals are generated by the outputs 0 and 1,
respectively of set/reset flip-flop 609. The set input S of
flip-flop 609 is connected to the output of AND-circuit 610 whose
inputs are connected to the KLC and DOB signal lines while the
reset input R of flip-flop 609 is connected to the KLC' and DOB
signal lines. Note inverter 612 shows how the KLC signal is
inverted to obtain the KLC' signal.
The margin control 24 (an examining means) shown in FIG. 7
comprises seven identical decoders 701, 702, 703, 704, 705, 706 and
707 having inputs connected via cabls SR1, SR2, SR3, SR4, SR5, SR6
and SR7, respectively, to the outputs of the first, second, third,
fourth, fifth, sixth and seventh stages, respectively of shift
register 12. A typical decoder 701 senses for the coded combination
of bits associated with either a space, a carrier return or a
hyphen byte (a possible end of line byte) and transmits a signal
from its output upon such sensing. The outputs of all the decoders
are connected to inputs of OR-circuit 708 whose output is connected
via inverter 709 and line 710 to an input of AND-circuit 711. Thus,
line 710 will be low whenever a possible end of line byte is in
shift register 12 (FIG. 1) otherwise the line will be high.
A second input of AND-circuit 711 is connected to line LOOK which
is connected to the output 1 of edge-triggered flip-flop 712 whose
other output "0" is connected to line LOOK'. The data input D of
the flip-flop is connected to the MARGIN line and the clock input C
of the flip-flop is connected to the output of OR-circuit 713
having inputs connected to the AUTO and KCR lines. The CHARF signal
line is connected to the third input of AND-circuit 711 whose
output is connected to the STOPA signal line and via line 714 to
the STOPA' signal line. Generally, a MARGIN signal sets flip-flop
712 to generate the LOOK signal which samples AND-circuit 711. If
line 710 is low nothing further happens until there is a carrier
return with the KCR signal clearing flip-flop 712. If line 710 is
high the STOPA signal is generated stopping automatic operation and
the operator must go onto manual operation. When the operator
depresses the one character switch OCSW (FIG. 3) for the first time
the CHARF' signal disappears blocking AND-circuit 711 and
terminating STOPA signal. When the operator thereafter depresses
the auto switch ASW (FIG. 3) to restart automatic operation, the
AUTO signal clears flip-flop 712 or if the operator manually
inserts a carrier return the KCR signal will clear the flip-flop
712.
Thus, there has been shown a record medium controlled typewriter
system. While the record medium was described as a magnetic tape in
a cassette type tape recorder, other record media such as magnetic
cards, punched paper tapes, punched cards or even computer or data
terminal sources could be used.
In the claims certain terminology will be used. A graphic is
intended to mean an alphabetic character, a numeric character or a
symbol. By print formatting movements is meant carrier returns,
hyphenating or spacing. Print positioning movement means
positioning the printing device (the carrier) with respect to the
record medium. Start of line print positioning movement means
moving the printing device to the left margin plus a single line
advance, i.e., a carrier return and line advance.
* * * * *