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Claims  |
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I claim:
1. A printer for a bowling game scoring computer for simultaneously
printing the game score history of a plurality of bowlers comprising
a linear array of dot print elements;
means for storing ball-by-ball, frame, and game score data characters for
said plurality of players;
means for converting one of said stored characters for each of said players
whose history is to be printed to data having a dot display compatible
format;
means for transferring a columnar portion of said data representing each of
said converted characters for each player whose score history is being
printed as selective enabling signals to said print elements; and
pulse means for energizing ones of said plurality of print elements
selected by said transferred data whereby a representation of the
converted characters of said player's game score is printed on a
column-by-column basis;
said pulse means further energizing selected ones of said print elements to
print simultaneously a rectangular background grid for said game score
comprising horizontal and vertical interlaced lines.
2. A printer as claimed in claim 1 further including a clock pulse source
for controlling the transfer of said columnar portions of characters by
said transferring means, and means for printing a rectangular background
grid for said frame score data including means included in said
transferring means for simultaneously energizing every one of said
elements of said linear array to print a vertical line of said grid;
and means directly responsive to said clock pulse source for energizing
selected ones of said linear array of print elements with every operation
of said pulse means to print horizontal lines of said grid.
3. A printer as claimed in claim 2 including
thermally responsive paper as a recording medium,
said print elements comprising resistors for selectively forming dots on
said recording medium.
4. A printer as claimed in claim 3 wherein said transferring means includes
register means for storing said converted data, and
first signal means for gating said converted data into said register means
to form said enabling signals for said print elements.
5. A printer as claimed in claim 4 wherein said pulse means comprises a
monostable multi-vibrator having a period shorter than the storage time
for said dot format data stored by said register means.
6. A printer as claimed in claim 1 wherein said linear array of print
elements is divided into a plurality of sectors, said transferring means
includes a register means including plural registers for storing said
converted data, each register of said register means having an input
connected to said storing means, and a plurality of outputs, each of said
outputs connected to a print element in each of a plurality of said
sectors.
7. A printer as claimed in claim 6 wherein each of said sectors includes a
sufficient number of said print elements to print the game score of one of
said players.
8. A printer as claimed in claim 7 wherein each of said sectors further
comprises a sufficient number of print elements to print background grid
lines for the player's game score printed by said sector's elements.
9. A printer as claimed in claim 8 further including a clock pulse source
for controlling the transfer of said columnar portions of characters by
said transferring means, and means for printing a rectangular background
grid for said frame score data including means included in said
transferring means for simultaneously energizing every one of said
elements of said linear array to print a vertical line of said grid;
and means directly responsive to said clock pulse source for energizing
selected ones of said linear array of print elements with every operation
of said pulse means to print horizontal lines of said grid.
10. A printer as claimed in claim 7 wherein each of said sectors comprises
about one-fourth of said print elements in said linear array.
11. A printer as claimed in claim 6 wherein said pulse means comprises a
plurality of phase drive lines, one for each of said sectors, for carrying
drive pulses to said selected print elements.
12. A printer as claimed in claim 11 wherein each of said sectors includes
a sufficient number of said print elements to print the game score of one
of said players.
13. A printer as claimed in claim 12 further including a clock pulse source
for controlling the transfer of said columnar portions of characters by
said transferring means, and means for printing a rectangular background
grid for said frame score data including means included in said
transferring means for simultaneously energizing every one of said
elements of said linear array to print a vertical line of said grid;
and means directly responsive to said clock pulse source for energizing
selected ones of said linear array of print elements with every operation
of said pulse means to print horizontal lines of said grid.
14. A printer as claimed in claim 11 further comprising print drivers
connected between each of said phase drive lines and the print elements
energized thereby, each print driver comprising at least one transistor,
and means for detecting the failure of any of said print driver transistors
comprising
a first inverter whose output defines a print fail signal indicating
failure of one of said print driver transistors, and having a plurality of
inputs including each of said phase drive lines and a second inverter
coupled between said print drivers and said first inverter.
15. A bowling computer system including means for storing game scoring data
comprising the ball-by-ball frame and total game score history of bowling
games for a plurality of bowlers; means for printing said stored data,
wherein the improvement comprises said printing means having a linear
array of adjacent dot print elements, said array being of sufficient
length to print simultaneously the game scoring data for all of said
players and a rectangular background grid comprising horizontal and
vertical interlaced lines.
16. A system as claimed in claim 15 including a random access memory for
storing said score history in binary data character format, means for
transmitting the data to said printer comprising
means for converting one of said stored data characters for each of said
players whose history is to be printed to data having a dot display
compatible format;
means for transferring a columnar portion of said data representing each of
said converted characters for each player whose score history is being
printed as selective enabling signals to said print elements; and
pulse means for energizing ones of said plurality of print elements
selected by said transferred data whereby a representation of the
converted characters of said player's game score is printed on a
column-by-column basis by said printing means in alignment with said
background grid.
17. A system as claimed in claim 16 further including a clock pulse source
for controlling the transfer of said columnar portions of characters by
said transferring means, and wherein said means for printing said
rectangular background grid for said frame score data including means
included in said transferring means for simultaneously energizing every
one of said elements of said linear array to print said vertical lines of
said grid;
and means directly responsive to said clock pulse source for energizing
selected ones of said linear array of print elements with every operation
of said pulse means to print said horizontal lines of said grid.
18. A printer as claimed in claim 17 including
thermally responsive paper as a recording medium,
said print elements comprising resistors for selectively forming dots on
said recording medium.
19. A system as claimed in claim 18 wherein said transferring means
includes register means for storing said converted data, and
first signal means for gating said converted data into said register means
to form said enabling signals for said print elements.
20. A system as claimed in claim 19 wherein said pulse means comprises a
monostable multi-vibrator having a period shorter than the storage time
for said dot format data stored by said register means.
21. A system as claimed in claim 20 wherein said linear array of print
elements is divided into a plurality of sectors, said register means
having an input connected to said storing means, and a plurality of
outputs, each of said outputs connected to a print element in each of a
plurality of said sectors.
22. A system as claimed in claim 21 wherein each of said sectors includes a
sufficient number of said print elements to print the game score of one of
said players.
23. A system as claimed in claim 22 wherein each of said sectors further
comprises a sufficient number of print elements to print background grid
lines for the player's game score printed by said sector's elements.
24. A system as claimed in claim 22 wherein each of said sectors comprises
about one-fourth of said print elements in said linear array.
25. A system as claimed in claim 21 wherein said pulse means comprises a
plurality of phase drive lines, one for each of said sectors, for carrying
drive pulses to said selected print elements.
26. A system as claimed in claim 25 wherein each of said sectors includes a
sufficient number of said print elements to print the game score of one of
said players.
27. A system as claimed in claim 21 further comprisng print drivers
connected between each of said phase drive lines and the print elements
energized thereby, each print driver comprising at least one transistor,
and means for detecting the failure of any of said print driver transistors
comprising
a first inverter whose output defines a print fail signal indicating
failure of one of said print drive transistors, and having a plurality of
inputs including each of said phase drive lines and a second inverter
coupled between said print drivers and said first inverter.
28. A system as claimed in claim 17 wherein said transferring means
includes register means for storing said converted data, and
first signal means for gating said converted data into said register means
to form said enabling signals for said print elements.
29. A system as claimed in claim 28 wherein said linear array of print
elements is divided into a plurality of sectors, said register means
having an input connected to said storing means, and a plurality of
outputs, each of said outputs connected to a print element in each of a
plurality of said sectors.
30. A system as claimed in claim 29 wherein said pulse means comprises a
plurality of phase drive lines, one for each of said sectors, for carrying
drive pulses to said selected print elements.
31. A system as claimed in claim 30 further comprising print drivers
connected between each of said phase drive lines and the print elements
energized thereby, each print driver comprising at least one transistor,
and means for detecting the failure of any of said print driver transistors
comprising
a first inventor whose output defines a print fail signal indicating
failure of one of said print driver transistors, and having a plurality of
inputs including each of said phase drive lines and a second inverter
coupled between said print drivers and said first inverter. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
Automatic bowling scorer systems that include score printing apparatus are
known in the art. In some of these systems the printers print the game
score data at the completion of each frame of the game. In some known
boiling scorer printer systems of this type, the paper onto which the
frame-by-frame and game total scores are printed already has printed
thereon a bowling scoresheet grid pattern which defines the areas where
the players' frame-by-frame and game total scores are to be located.
Because of alignment problems that frequently occur between the print head
and the pre-printed paper, the frame and total scores are not always
printed in the designated areas defined by the grid pattern. This problem
is compounded by the fact that players do not always bowl in their
assigned sequence, in which case the next score to be printed may be above
or below and/or to the left or right of the last printed score. Therefore,
typically, the printer portion of an automatic bowling scorer system is
one of the more complicated and least reliable portions of that system.
Even in a known system where the game score data is printed out only after
a game is completed, such as disclosed in Warner U.S. application Ser. No.
319,353 filed Dec. 29, 1972, the printed information is not in the usual
bowling scoresheet format comprising a parallel line for each bowler, and
the printout is not made against a pre-printed background grid.
SUMMARY OF THE INVENTION
It is the object of this invention to provide a bowling scorer printer
capable of printing all game score data for a plurality of players in a
very short time, on command, and without any alignment problem between
print head and the scoresheet grid pattern. This and other beneficial
objects are achieved by a printer having a linear array of dot print
elements. Five successive energizations of the array of dot print elements
are required to form each character on an advancing strip of blank paper.
Predetermined ones of the dot elements are activated on each energization
of the array to form respective characters. After each frame score has
been printed, all dot print elements are activated to print the vertical
lines of the bowling scoresheet grid pattern. Designated ones of the dot
print elements are activated with each energization of the array to
concurrently print the horizontal lines of the grid pattern. The dot print
array is of sufficient height to print the game score data for all the
players on the team substantially simultaneously, frame by frame, based on
the game score data stored in the random-access memory of the bowling
computer.
CROSS REFERENCE TO RELATED APPLICATIONS
For details of a typical scoring format by which a computer can determine
game score data from stored ball score data, see Warner U.S. application
Ser. No. 319,353 assigned to the assignee of this invention, the entire
disclosure of which is incorporated hereby in reference.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a block diagram of the printer and print control system.
FIG. 2A is an exemplary score sheet printed by the printer of this
invention. FIG. 2B is an exemplary frame score as printed by this
invention.
FIG. 3A is a detailed schematic of the means for transmitting control
signals to the print head; FIG. 3B is a detailed schematic of the print
head.
DESCRIPTION OF A PREFERRED EMBODIMENT
A block diagram of the overall system is shown in FIG. 1, and an example of
the resultant printed scoresheet is illustrated in FIG. 2A.
The printer 2 includes a printhead 4 and a stepping motor 6 for advancing a
strip of thermally active paper past the printhead. The printhead 4 is
comprised of two substantially identical printheads 4A and 4B mounted end
to end. These individual printheads are of a design manufactured by Gulton
Industries, Metuchen, N.J., the matrix used to selectively energize the
dot print elements shall be fully disclosed herein. Each individual
printhead assembly 4A, 4B has an arrangement of 67 dot print elements in a
linear array so that the complete printhead assembly 4 has a linear dot
array of 134 dot print elements. The dot print elements on the printhead 4
are individual thick firm resistor elements which heat up upon the passing
of electrical current therethrough. The dot print element have a fast
thermal cycle which permits them to heat and cool rapidly upon the
application and termination of current flow therethrough. The surface of
thermal printhead 4 is in contact with a strip of thermographic (heat
active) paper and the heated print dot elements on the printhead 4 produce
corresponding dots on the thermographic paper.
As shown in FIG. 2A, for purposes of printing data comprising the headings,
game and frame information and totals, the total vertical space to be
imprinted is divided into 16 rows DR0-DR15. The upper printhead assembly
4A prints the top two horizontal lines L1, L2 associated with the heading
to be printed upon the scoresheet (see FIG. 2A), the three horizontal
lines L3, L4, L5 defining the scoresheet grid for the first three players
and all rows DR1-DR7 of character data lying between these lines; the
lower head 4B prints the lines L6, L7 defining the grid for the three
lower players, the lines L8, L9 associated with player total information
and all rows DR8-DR14 of character data lying between lines DR8-DR14. Of
course, all dot elements are energized to print the vertical lines L10-L23
of the background grid.
The thermal print heads are multiplexed, to minimize the number of signal
lines that must be routed to them. The 16 rows DR10-DR15 are grouped into
4 quadrants, Q0, Q1, Q2, Q3 (see the right hand side of FIG. 2A). With 4
quadrants multiplexed it is no problem to maintain less than 25% duty
cycle on each resistor dot element prolonging element life. This is true
so long as all 4 quadrants are used for printing on each cycle, which is
true in this system.
Referring to the printer layer sheet of FIG. 2A, the data print rows as
numbered from DR1 through DR14 are divided for printing purposes into the
following head/quadrant combinations:
______________________________________
Row Head Quadrant
______________________________________
DRO* A 0
DR1 A 0
DR2 A 1
DR3 A 1
DR4 A 2
DR5 A 2
DR6 A 3
DR7 A 3
DR8 B 0
DR9 B 0
DR10 B 1
DR11 B 1
DR12 B 2
DR13 B 2
DR14 B 3
DR15* B 3
______________________________________
Note that while FIG. 2A has only 14 printed rows of data DR1-DR14, 16 rows
are provided for in the above table. Rows DR0 and DR15 (marked with
asterisks) never have character data to be printed, but control signals
are issued as if the two lines do exist; blank characters (no dots on) are
issued to rows DR0 and DR15. This scheme is used merely to simplify the
overall design by avoiding the special cases at each end of the dot
element array.
The data to be printed is stored in the memory of the bowling score
computer shown in the block diagram of FIG. 1. The computer includes a
random-access memory 10 for storage of ball-by-ball, game and frame score
data. Microprocessor MPU 12 performs data computation operations in
accordance with a program stored in read-only memory ROM 14.
Peripheral interface adapter PIA 16 is the communications link between the
microprocessor 12 and its associated devices, i.e., random-access memory
10; read-only memory 14 and printer system 2. The PIA 16 recognizes an
address and gives the microprocessor 12 access to that address. In the
preferred embodiment of this invention, the microprocessor 12 is a
Motorola 6800, and PIA 16, which must of course, be compatible therewith,
is a Motorola 6820.
The significant data outputs from the PIA 16 to the printer of this
invention are the lines PB0-4 carrying the data which define each
character to be printed in the rows DR0-DR14; printer storage register
control signals E1-E3 for causing storage of the character defining data;
phase drive signals S1.varies.S4 for energizing the dot print elements
selected by the developed data to print each character, or to print the
lines of the background grid; the signal V.LINE for causing a vertical
line print; the signal H.LINE for causing horizontal line print; and the
signal PAPER ADVANCE for energizing the paper advance mechanism 6.
Provision is also made for transmitting a PRINT FAIL from the print head 4
back to the PIA 16; in the event of a failure in the printer head 4, data
transmission is thereby halted.
The timed relationship of all the signals mentioned above appears in the
context of the following description of the overall invention.
As shown in FIG. 2B, each character in each row DR1-DR14 of the full
printout shown in FIG. 2A is printed by defining it in terms of the
significant dots in a 5-by-5-dot matrix. It has been explained above that
4 quadrants, each quadrant comprising 4 rows, must be printed to print the
full height of the scoresheet; and as shown in FIG. 2B, 5 print cycles in
the row direction are required to print a complete character. The control
signals to be discussed below provide for this character printing
sequence.
System timing requires only a simply counting routine for counting the
width of a frame space, and the width of characters within the space, in
accordance with the dot count sequence illustrated in FIGS. 2B.
This is accomplished using the following sequence, starting from the left
side vertical column as shown in FIG. 2B:
1. print full vertical column;
2. print 2 columns of horizontal line dots;
3. transfer a character for each of the 14 rows DR1-DR14 to a buffer
storage area in RAM 10;
4. look up the 5-by-5 dot format data as stored in ROM 14 for each stored
character;
5. transfer on lines PB0-PB4 one column of dot format data for each of the
character rows DR1-DR14 (rows DR0, DR15, no data is calculated or
transmitted); data is transferred in the sequence DR1, DR8, DR9, DR2, DR3,
DR10, DR11, DR4, DR5, DR12, DR13, DR6, DR7, DR14;
6. energize a register enable line E1-E3 to store the data presented on
lines PB0-PB4 until printing; (only the first three rows of each quadrant
are stored in registers RG1-RG3; the fourth row is applied directly to the
print head on lines PB0-PB4;
7. after each 4 data row transfers, i.e., 1 quadrant, energize the one of
driver strobes S1-S4 coincident with the rows of data transferred;
8. after the fourth quadrant is printed, pause for paper advance;
9. repeat steps 5-7 four times to print a full column of characters.
For example, to print column CA of FIG. 2A, to accomplish step 3,
characters 9, 6, 6, 7, 7, would be stored in storage areas in RAM 10
allocated to print rows 4, 6, 8, 10, 12, respectively; no character would
be stored for the other rows. The table lookup is performed for the stored
characters, and a one of the five columns of dot character information is
transmitted to the printer.
This fetch routine is simplified by storing the characters to be printed in
columnar array relative to one another in memory. The characters of the
character column are converted through a lookup table into a binary word
whose bits correspond to the darkened dots on the next dot column. Of
course, each character being represented by a 5-by-5 matrix, 5 columns of
dot format data are required to print all the characters in a given
column. After each selection of the characters to be printed in a column,
e.g., column CA, in the course of printing the column, 5 lookups are
performed of each character in the column to establish the 5 separate
successive sets of dot column data representing vertical character
segments that are necessary to print each character. A simple counting bit
routine keeps track of which dot column within a given character column is
being printed. This system uses 5 lookups to save storage space; this
modification is available because of the relatively low horizontal speed
of the printer. Table lookups for data conversion and display in dot
format are well-known in the art, e.g., Koster et al U.S. Pat. No.
3,346,853 or Mau et al U.S. Pat. No. 3,868,673.
After conversion, the dot sets representing the character segments are
transferred via the PIA to the register RG1-RG3 (FIG. 3A) via 5 data lines
PB0-PB4 which are connected to each of registers RG1-RG3. Signals appear
in succession on control lines E1-E3 to store the dot-representing data
signals in registers RG1-RG3. In this manner the data signals for the
first three rows of each quadrant (there being four quadrants to each
column) are stored. The signals for the character segment defined for the
fourth row of the quadrant are not stored in registers; they are applied
directly to one side of the print head drive matrix as illustrated in FIG.
3A. The three registers RG1-RG3 each have 5 outputs for a total of 15
outputs connected respectively to print control leads M1-M15. The data
lines PB0-PB4 are also directly connected to control leads M16-M20, a
fourth subgroup of the dot print leads. In this way a quadrant including
dot segments for 4 rows is prepared for printing, the registers RG1-RG3
and data lines PB0-PB4 providing the resistor selection signals to one
side of the print matrix (FIG. 3B) on inputs M1-M20. It can be seen from
FIG. 3B, the detailed schematic diagram of one of the two print head
portions 4A, 4B that each print control lead M1-M20 runs to four dot print
elements. For example, control lead M6 runs to dot elements R10, R27, R44,
R61. Which of these four dot elements is to be energized while a given
data bit is present is determined by phase drive lines S1-S4. These
signals S1-S4 are applied in succession; they are generated in sequence to
follow the respective sets of data signals defining quadrants 0, 1, 2, 3
so that the appropriate data which has been stored in registers RG1-RG3 is
applied to leads M1-M20 when the respective drive signal appears.
The duration of application of drive signals S1-S4 is fixed by common
multi-vibrator 30 (FIG. 1) enabled by a signal coincident with the leading
edge of each of signals S1-S4; the one-shot multi-vibrator 30 is used so
that timing is provided through the drivers 50,51,52,53 rather than by
separate signals from the MPU.
In summary, the dot resistors are selected by the data stored in registers
RG1-RG3 by signals E1-E3, and by signals on the lines PB0-PB4 applied
directly to the print head. Then signals appear on lines S1-S4, their
duration limited to about 5 milliseconds by milti-vibrator 30 during which
the dot pattern (see FIG. 3B) is thermally printed on the printer paper.
Diode circuitry D1,D2, D3, D4, shown on the right hand side of FIG. 3A
provides means for detecting the absence of a voltage drop across the
phase driver transistors whenever these drivers are driven into cut-off. A
printer-fail signal is generated for transmission back to the PIA 16 if
these drivers are found to be shorted out; this signal is used to shut off
the printer in order to protect the print heads.
To consider FIG. 3B in detail, it illustrates the relationship between the
16 rows DR0-DR15 into which data is divided for purposes of transfer to
the print head, and the actual printing resistors of the thermal dot print
elements. The figure shows the print head section 4A; print head section
4B is of like construction, with the only difference being clearly marked
on FIG. 3B. Print head 4A includes 67 thick film resistors R1-R68 on a
common substrate. The resistors to be energized to print each column of
dots are selected by the data lines M1-M20; the timing of the print cycle
is provided by strobe lines S1-S4. Basically, a resistor is energized to
print a dot only when a signal is received both on a data line (M1-M20)
and a strobe line (S1-S4). It is apparent, e.g., that lines M1-M10 control
the printing of rows DR1-DR7, with the specific quadrant in which printing
is to occur being selected by successive phase drive signals S1-S4. The
selection and energization processes were explained fully above with
respect to FIG. 3A, on which these lines also appear.
Comparing the diode matrix of FIG. 3B to the printout of FIG. 2A, no data
is ever printed in lines DR0 and DR15. Therefore no diodes are connected
to the topmost resistors R1-R7 of the upper head 4A which would be used to
print row DR0; and no diodes are connected to the resistors corresponding
to R61-R68 on lower head 4B, which would be allocated to row DR15.
Connections do exist to element R7 on head portion 4A, and element R61 on
head 4B as these are used to print horizontal lines of the background
grid.
The allocation of printing resistors R1-R68 to printing of specific
character rows DR1-14 appears from a comparison of FIG. 3B with FIG. 2B
which show character height and spacing in each frame.
FIG. 2B shows that each frame has the following vertical array:
a solid horizontal line, 1 dot in height;
a 2 dot space;
a character 5 dots in height;
a 2 dot space;
a character 5 dots in height;
a 2 dot space;
a 1 dot horizontal line.
The frame of FIG. 2B could be printed in rows DR2 and DR3 of a frame score
printout (FIG. 2A) using the following resistors:
solid horizontal line -- R17
2 dot space -- R18, 19
5 dot character -- R20...24
2 dot space -- R25, 26
5 dot character -- R27,...31
2 dot space -- R32, 33
solid horizontal line -- R34
The wiring connections of significance in printing the game score
background grid for these exemplary rows DR2, DR3, are the connection of
resistors R34 between strobe line S2 and H-LINE signal input and the
connection of resistors R17 and R7 between strobe line S1 and the H-LINE
signal input to energize these resistors with every frame count signal
(explained below) to print appropriate portions of horizontal lines of the
background grid; and the connection (again taking only print rows DR2 and
DR3 for an example) of resistors R18, R19, R25, R26, R32, R33 between the
V-LINE signal input and common strobe S2 so that a continuous vertical
line of the background grid including those dots never used to print
character data can be printed. Of course, to print the solid vertical
line, in addition to energizing the special V-LINE input, all the data
lines M1-M20 and each of the strobe lines S1-S4 are energized to print the
complete vertical line.
As to timing the printing of the background grid, the basic frame clock
signal rate which is used to count the width of the frame is applied to
the H-LINE wire to serve as that signal. For the vertical line, a simple
counter to count to 24 (the width of each of the frames 1-9) or 31 (for
frame 10 and the TOTAL and HDCP columns) or 115 (for the name column)
provides the necessary V-LINE output signals. A repetitive count of 7
comprised of 5 counts for each character (letter or number, both being
printed in a 5-by-5 matrix) and 2 counts for the space preceding each
character, provides the basic character space count. This basic count is
multiplied by 3 for frames 1-9; by 4 for frame 10, and the TOTAL and HDCP
columns; and by 16 for the name column. After the necessary character
spaces for a column width are counted, 2 counts are added for spacing
after the final character space, and one final count is added, being the
horizontal line count pulse, causing transmission of the H-LINE signal.
Such a counter is well within the still of the art and is not pictured in
detailed here.
The major timing limitation with respect to the energization of each dot
element R1-R68 is that when a dot has been fired, the signal must remain
applied for five milliseconds in order to heat the thermal paper. This is
accomplished by strobe lines S1-S4 which time the energization of each dot
print resistor after selection by the data lines. One shot multi-vibrator
30 provides the five-millisecond timing pulse. The paper advance 6 is
simply a strobe signal applied through an amplifier to the solenoid 6S of
stepping motor 6M in timed relationship to the printing of each column of
dots.
The PRINT FAIL signal is developed as follows:
The outputs 35-38 of the drivers 50-53 are applied to an A2J transistor
inverter 54 via diode OR-gate 55. These outputs are normally low, i.e.,
they track the state of the input signals S1-S4 on lines 39-42. The output
of the inverter 54 is therefore normally high, holding A2J inverter 56 low
and preventing a print fail signal. If a transistor in any driver section
50-53 fails or shorts out, the output of that section will go high,
forcing the output of inverter 54 low and allowing the output of inverter
56 to go high, resulting in a PRINT-FAIL signal.
Of course, at timely intervals lines 35-38 must go momentarily high with
each print drive signal S1-S4 being carried to the print head. However,
these high outputs correspond to high signals S1-S4 incoming on lines
39-42. These incoming signals are carried to inverter 56 via diode OR-gate
47, holding the output of inverter 56 low for the duration of the print
drive pulse, and preventing a spurious PRINT-FAIL signal.
The 4-quadrant print cycle is conducted with the paper at rest to avoid
"wavy" lines in the output. However, paper motion can be and is initiated
while the last quadrant is being printed, in order to increase print
speed. This is possible for the following reasons.
The paper motion cycle can be broken down into three phases: (1) solenoid
actuation; (2) acceleration; and, (3) decelerction. Phase 1 takes place
before acceleration, and requires about 7 milliseconds; this time is
required to transfer energy into the solenoid through the rather large
inductance in the coil. Once acceleration begins, speed increases to a
peak, and then deceleration takes over. The combined
acceleration-deceleration phases require an additional 7 milliseconds.
Quadrants are printed in the order 0,1,2,3; each quadrant requires 5
milliseconds to print. Therefore, 3 milliseconds into quadrant 2, the
paper advance strobe can be issued. Then, paper motion will not actually
being until quadrant 3 signals have produced a print in the paper and
terminated.
Therefore, after quadrant 3 is printed, the software counts out a 7
millisecond period to allow completion of the acceleration-deceleration
phases.
The 7 milliseconds' wait will be used to prepare the next 14 characters,
i.e., 1 character per row, for printing the next column of the score card.
The data characters to be printed on the next printout column are fetched
from RAM 10 when this print pause is running, and after conversion the
print sequence proceeds with printing this next printout column. At the
completion of printing, the complete 5-by-5 matrix which will establish a
complete character for each row where printing should occur, then the
paper again moves past 2 dot spaces; if the frame is completed, all of the
resistors not used to print the 5-by-5 data matrices on horizontal line
are energized by a signal on a separate line V-LINE; simultaneously,
signals are sent to leads M1-M20 and H.LINE. In this manner, the vertical
line of the scoring grid is formed on the paper. Breaking down of the
characters into rows of 5-by-5 word matrices and printing of both
characters and grid lines in this dot-type fashion allows high-speed
printing of all the game score data for all the players on a team
participating in a game.
The result is a fast, readable, and accurate printout of game score data at
any desired time in the course of a game.
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