U.S. patent number 3,880,075 [Application Number 05/427,477] was granted by the patent office on 1975-04-29 for automatic chain identification method and apparatus.
This patent grant is currently assigned to Burroughs Corporation. Invention is credited to Robert E. Bohn, Duane E. Bovett.
United States Patent |
3,880,075 |
Bovett , et al. |
April 29, 1975 |
Automatic chain identification method and apparatus
Abstract
Chain printers presently in the art are constructed to permit
replacement or changing of the type carriers to facilitate the use
of a variety of character sets or fonts. In order to handle a
plurality of type slug carriers of different fonts, a translator
must be provided for each font set. In order to indicate that the
translator being used matches the font set of the type carrier
placed on the printer, several teeth on the type carrier are filed
down. The filed teeth are later sensed as an identification code
unique to that type carrier. This code is stored in a register in
the printer controller to be compared with a code in another
register that identifies the translator being used.
Inventors: |
Bovett; Duane E. (Claremont,
CA), Bohn; Robert E. (Pasadena, CA) |
Assignee: |
Burroughs Corporation (Detroit,
MI)
|
Family
ID: |
23695046 |
Appl.
No.: |
05/427,477 |
Filed: |
December 26, 1973 |
Current U.S.
Class: |
101/111;
101/93.01; 101/93.14 |
Current CPC
Class: |
B41J
1/20 (20130101) |
Current International
Class: |
B41J
1/00 (20060101); B41J 1/20 (20060101); B41j
001/20 () |
Field of
Search: |
;101/111,93C,110,426 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
IBM Technical Disclosure Bulletin, Vol. 15, No. 10, March 1973,
Gilbreth et al., pp. 3113-3114..
|
Primary Examiner: Burr; Edgar S.
Assistant Examiner: Coven; Edward M.
Attorney, Agent or Firm: Gess; Albin H. Cass; Nathan
Peterson; Kevin R.
Claims
What is claimed is:
1. In a chain printer wherein the type carrier has a font set
thereon and utilizes a plurality of teeth for engaging driving
mens, apparatus for generating a unique binary code identifying the
font set on the carrier comprising:
a predetermined plurality of flattened teeth located on said type
carrier so as to be representative of said unique binary code;
sensing means adjacent said type carrier for sensing the flattened
teeth when said type carrier is being driven; and
means responsive to said sensing means for generating a binary code
representative of the sensed flattened teeth.
2. The apparatus of claim 1 further comprising:
means for storing the binary code representative of the sensed
flattened teeth;
means for storing a standard binary code; and
means for comparing the binary codes stored in said storing
means.
3. The apparatus of claim 2 wherein said storing means for storing
a binary code representative of the sensed flattened teeth comprise
a serial-input, parallel-output shift register.
4. In a chain printer wherein the type carrier has a font set
thereon and utilizes a plurality of teeth for engaging driving
means, a method for generating a unique binary code identifying the
font set on the type carrier comprising:
flattening a plurality of teeth on said carrier in a preselected
order representative of said unique binary code;
sensing the flattened teeth when said type carrier is driven;
and
generating a binary code representative of the sensed flattened
teeth.
5. The method of claim 4 further comprising:
storing the binary code representative of the sensed flattened
teeth;
storing a standard binary code; and
comparing the stored binary codes.
6. In a chain printer wherein the type carrier has a font set
thereon and utilizes a plurality of teeth for engaging driving
means, one of said teeth being physically modified and sensed by a
detection means for generating a synchronizing pulse, apparatus for
generating a unique binary code identifying the font set on the
carrier, comprising:
an additional plurality of physically modified teeth located on
said type carrier displaced from the physically modified tooth for
representing said binary code, said additional plurality of
physically modified teeth being sensed by said detection means;
and
means responsive to said detection means for generating the binary
code represented by said representing means.
7. The apparatus of claim 6 further comprising:
means for storing the generated binary code;
means for storing a standard binary code; and
means for comparing the binary code stored in said storing
means.
8. The apparatus of claim 7 wherein said physically modified teeth
are flattened, and wherein said storing means for storing the
binary code generated by said detection responsive means comprises
a serial-input, parallel-output shift register.
9. In a chain printer wherein the type carrier has a font set
thereon and utilizes a plurality of teeth for engaging driving
means, a method for generating a unique binary code identifying the
font set on the type carrier, comprising:
physically modifying a predetermined plurality of said plurality of
teeth at predetermined locations on said type carrier so as to be
representative of said unique binary code;
sensing the physical modification of said predetermined plurality
of said teeth; and
generating a binary code representative of the physical
modification.
10. The method of claim 9 wherein said physically modifying
comprises flattening said predetermined plurality of teeth, and
further comprising:
storing the generated binary code;
storing a standard binary code; and
comparing the stored binary codes.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to improvements in chain
printers and more particularly pertains to the type of chain
printers that are able to interchangeably utilize a variety of
different font set type carriers. Examples of such printers can be
found in patents having U.S. Pat. Nos. 3,699,884 and 3,629,861.
When a variety of interchangeable font set type carriers are
available for use on the same printer, a broblem arises in insuring
that the translate table, utilized for converting the character
code signals into type carrier position signals, matches the
particular font set type carrier that has been placed in the
printer.
SUMMARY OF THE INVENTION
An object of this invention is to prevent a chain printer from
operating with a type carrier having a character or font set that
does not correspond with the translator being used.
Another object of this invention is to compare the identification
code generated by the type carrier placed in the chain printer with
the code identifying the translator being used.
These objects and the general purpose of this invention are
accomplished by flattening a unique sequence of teeth on each
unique type carrier and sensing these teeth in order to generate a
unique identification code. This code which would be a sequence of
binary ones and zeroes, would be stored in a register for
comparison with a binary code stored in another register that
identifies the translator being used. A match of the two codes may
be used to product an indication to that effect.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and many of the attendant advantages of this
invention will be readily appreciated as the same becomes better
understood by reference to the following detailed description when
considered in conjunction with the accompanying drawings in which
like reference numerals designate like parts throughout the figures
thereof and wherein:
FIG. 1 shows a perspective view of drive wheels and a type carrier
that is common to a chain printer.
FIG. 2 illustrates in block and logic diagram form an embodiment of
the circuitry associated with the present invention.
FIG. 3 is a pulse diagram illustrating the signals present at
various points of the circuitry of FIG. 2 during its operation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates the typical arrangement in a chain printer of a
type carrier 15 and driving wheels 11 and 13. The type carrier, or
belt 15, has mounted thereon a plurality of type slugs which carry
the font set 17 illustrated as the blocked alphabet A, B, C, D etc.
The type slugs are backed with teeth 19 that engage the driving
wheels 11 and 13 to be driven in a non-slipping manner.
The font set of a particular type carrier 15 may be identified by
filing flat a certain minimal combination of these teeth 19. For
example, by filing down three teeth 21, 23 and 25, a certain
six-bit identification code may be produced. This provides for
2.sup.6 unique identification codes. The first flattened tooth 21,
assuming the type carrier is moving in a counter-clockwise
direction, represents a synchronizing pulse. The six teeth that
follow that synchronizing pulse represent the six digit type
carrier identification code. This code is generated by a
reluctance-type sensing device 27 every time that a flattened
tooth, like 23 for example, passes the reluctance sensor 27.
Reluctance sensors are considered well known in the art and will
not be further discussed herein. Every time a flattened tooth
passes the sensor, a pulse is generated on line 29 which delivers
that pulse to the printer control 31. The printer control
interfaces with a computer system over a communication link 33. Any
well known printer control utilized for chain printers may be
utilized for printer control 31. For example, the U.S. Pat. Nos.
3,699,884 and 3,629,861 illustrate one type of printer control that
may be used.
FIG. 2 illustrates an example of structure to practice the present
invention. This logic circuitry 35 is made up of a pair of AND
gates 37, 39; a D-type flip-flop 41 that receives the output of AND
gate 39; a one-shot multivibrator 43 that receives the output of
the flip-flop 41; a clock source triggered by the multivibrator 43
for clocking data from AND gate 37 into a serial-input
parallel-output register 47 and a parallel input, parallel-output
register 49; and a comparator 51 for receiving the outputs of the
two registers 47 and 49 and generating a signal to indicate a
match, or mismatch.
The operation of the circuitry of FIG. 2 will now be explained in
connection with the pulse trains of FIG. 3. The parallel-input,
parallel-output register 49 which, for example, may be a buffer
register manufactured by the Signetics Corporation, and listed in
their 1972 catalogue on page 3-16 as Buffer Register No. 8202,
receives the binary code identifying the translate table being
used. This buffer register may be loaded with, for example, a
six-bit binary code from the computer system, which contains the
translate table in memory, over a communication link 33, or it may
be manually inserted, either method being well known in the art and
not comprising any part of this invention. Prior to the initiation
of a print cycle, and during the initializing stage, then, the
buffer register 49 is loaded with a particular binary code. For
purposes of example, it shall be assumed that the binary code
loaded into the buffer register 49 is 010010, as shown in FIG.
3.
Upon a particular type carrier 15 (FIG. 1) being placed on the
chain printer, prior to a print cycle, the type carrier is rotated
several full revolutions so that the reluctance pickup 27 can sense
the flattened teeth on the carrier. The reluctance pickup 27 senses
the flattened teeth and generates a pulse on line 29 which is
connected to the appropriate circuitry in the printer control. The
appropriate circuitry 35 in the printer control receives these
pulses at point A which are illustrated in FIG. 3 as pulses 73, 75
and 77. These are the pulses generated for the specific example of
flattened teeth in FIG. 1. Obviously, many other combinations of
flat teeth might be used. The example chosen represents a six-bit
identifying code.
Prior to the reception of any pulses by the logic circuit 35 in the
printer control 31, the signal output of the one-shot multivibrator
43 in the logic circuit 35, which is illustrated at B of FIG. 3, is
low, causing an enabling input to be supplied to AND gate 39. This
same signal level is also supplied to AND gate 37 as an inhibiting
signal. At the time of occurrence, of the first pulse 73 sensed by
the pickup 27, AND gate 39 generates a pulse output on line 67 that
is supplied to the clock input of D-type flip-flop 41 causing the Q
output of the flip-flop to send a signal on line 69 to the one-shot
multivibrator 43, thereby initiating it. It may be assumed, for
purposes of example, that the multivibrator is of the type
manufactured by the Signetics Corporation and described in their
1972 parts catalogue on page 2-112 as Monostable Multivibrator No.
N74121.
Upon being initiated, the output of the multivibrator 43 goes high
thereby inhibiting AND gate 39 and enabling AND gate 37. In
addition, this high signal level is supplied over line 61 to a
clock source 45 causing the clock source to provide clocking
signals, over line 63, to a modulo counter 46 and a register 47
and, over line 65, to another register 49.
The clock source 45 may be the printer control system clock which
is tapped by the signal on line 61 or a timer, such as produced by
the Signetics Corporation and described in their 1972 catalogue on
page 6-49 as Timer No. 555, that is synchronized to the printer
control clock.
These clock signals, illustrated at D in FIG. 3, cause the data
pulses, appearing at the output of AND gate 37, on line 71 to be
clocked into the type carrier identification register 47. Register
47 may be of the type manufactured by the Signetics Corporation and
described in their 1972 catalogue on page 3-78 Serial input,
Parallel-output Shift Register No. 78273. Thus for example of
flattened teeth illustrated in FIG. 1, the pulses 75 and 77, as
well as the lack of pulses therebetween, occuring after the initial
synchronizing pulse 73, within the window generated by the
multivibrator 43 causes the contents of register 47 to be 010010.
Any pulses appearing on line 71 after the time-out of the one-shot
multivibrator 43 at 81 will not be clocked into the type carrier
identification register 47.
Upon the last bit of the six bit code being clocked into the
register 47, the modulo counter 46, which may, for example, be a
divide by six modulo counter such as manufactured by the Signetics
Corporation and described in their 1971 TTL family catalogue on
page 101 as Divide by Six Counter No. S5492, would, upon the
occurrence of the sixth clock pulse 83 on line 63 cause a pulse to
be generated and supplied to a comparator 51 by way of line 64.
At this time the six-bit binary code identifying the type carrier
is completely loaded in the type carrier identification register
47. Buffer register 49, and type carrier identification register 47
have their contents clocked out to comparator 51 by the last clock
pulse 83.
The comparator 51 may be a pre-packaged computer circuit
manufactured by the Fairchild Corporation and listed in their June
1972 catalogue on page 8-124 as Comparator No. 9324. The output of
the modulo counter 47 on line 64 would be connected to the enable
input of the comparator. Only the "=" output of the comparator
would be utilized. Thus, in case of a mismatch between any of the
like bits being compared, out of the contents of registers 47 and
49, it would be indicated as a signed level on line 53 of the
comparator 51.
This signal may be supplied to the computer system (not shown) to
inhibit the print cycle or may simply be supplied to a display
device (not shown) to warn an operator that a type carrier having
an incorrect font set has been loaded onto the chain printer.
What has been described is a method and particular apparatus for
preventing a type carrier to be utilized in a chain printer
whenever its particular translate table is not loaded in the
computer system. Obviously many modifications and variations of the
invention are possible in light of the above teachings. It is
therefor to be understood that within the scope of the appended
claims the invention may be practiced otherwise than as
specifically described.
* * * * *