US3734011A

US3734011A - Document encoding apparatus

Info

Publication number: US3734011A
Application number: US00072921A
Authority: US
Inventors: R Williams
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1970-09-17
Filing date: 1970-09-17
Publication date: 1973-05-22
Anticipated expiration: 1990-05-22
Also published as: JPS5512618B1; DE2146451A1; FR2108267A5; NL7112723A; BE772331A; CA944217A; SE376314B; GB1336914A

Abstract

Apparatus for printing on unit records or documents of at least two different lengths as they are being rapidly conveyed along a path and being operable to enter printed data thereon in designated field areas of the documents regardless of the lengths thereof. Included is a printing or encoding station having a print wheel for entering data in the field areas of the documents as they pass therethrough and further having a first photodetector on the downstream side of the station for sensing the leading edge of a document in the station and a second photodetector on the upstream side of the station for sensing the presence of the trailing portion of the document. Coupled to the photodetectors is an electrical control circuit which responds to the sensing of the leading and trailing portions of a document in the station for determining the distance from the leading edge of the document where data for the first of the several field areas will be entered thereon. Such distance determining means may be optionally controlled by a manual switch when batches of similar length documents are conveyed through the encoding station or controlled automatically by a circuit provision cooperating with the photodetectors and capable of determining the lengths of the documents passing through the station and spacing the entry of the data on the documents in accordance therewith. A feature of the invention relates to a further provision for making a fine adjustment in the event the locating of the field areas on the documents deviate from prescribed specifications.

Description

United States Patent 1191 Williams 1 May 22, 1973 [54] DOCUMENT ENCODING APPARATUS [75] Inventor: Richard M. Williams, Livonia, Mich.

[73] Assignee: Burroughs Corporation, Detroit,

Mich.

[22] Filed: Sept. 17, 1970 [21] Appl. No.: 72,921

[52] US. Cl ..10l/91,101/235 [51] Int. Cl ..B4ll 47/46, B41f 13/48 [58] Field of Search ..l0l/93 C,9l,2,

l0l/233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 287, DIG. 15, 297

[56] References Cited UNITED STATES PATENTS 2,084,097 6/1937 Long ..101/287 X 2,087,315 7/1937 Bugg ..101/287 2,111,124 3/1938 Naylor 101/DIG. 15 2,283,804 5/1942 Grant et al. ..l0l/297 2,321,405 6/1943 McFarlane et al. ..101/242 2,547,470 4/1951 Janke ..l0l/233 2,743,671 5/1956 Weber et al. ..l0l/235 2,903,965 9/1959 Eichenbaum et al.... 101/235 2,988,984 6/1961 Eckert et al. ..10l/2 3,039,385 6/1962 Siegel 101/91 3,191,526 6/1965 Ross 101/91 3,294,015 12/1966 Gartside 101/35 3,373,685 3/1968 Adams ..l0l/235 3,438,323 4/1969 Smitzer ..10l/233 3,573,589 4/1971 Berry ..318/601 Primary Examiner-William Penn Att0meyl(enneth L. Miller and Edwin W. Uren [57] ABSTRACT Apparatus for printing on unit records or documents of at least two different lengths as they are being rapidly conveyed along a path and being operable to enter printed data thereon in designated field areas of the documents regardless of the lengths thereof. Included is a printing or encoding station having a print wheel for entering data in the field areas of the documents as they pass therethrough and further having a first photodetector on the downstream side of the station for sensing the leading edge of a document in the station and a second photodetector on the upstream side of the station for sensing the presence of the trailing portion of the document. Coupled to the photodetectors is an electrical control circuit which responds to the sensing of the leading and trailing portions of a document in the station for determining the distance from the leading edge of the document where data for the first of the several field areas will be entered thereon. Such distance determining means may be optionally controlled by a manual switch when batches of similar length documents are conveyed through the encoding station or controlled automatically by a circuit provision cooperating with the photodetectors and capable of determining the lengths of the documents passing through the station and spacing the entry of the data on the documents in accordance therewith. A feature of the invention relates to a further provision for making a fine adjustment in the event the locating of the fie d areas on the documents deviate from prescribed specifications.

14 Claims, 8 Drawing Figures PAIENIEW $734,011

SHEET 1 0F 4 FlG.l

LARGER SMALL SIZE CHECK COIL M I INVENTOR.

RICHARD M. WILLIAMS BY; 3

ATTORNEY I II I I I I I I I I I I I I IBI I I I I PATENIEI'III-IIZZIW 3,734,011

SHEET 2 [IE 4 FIG.4

I I I I I I I I I 20 f I I/ BB I x84 I I I I IIIBI I I I I I I I I I I IVIBI I I I I I I I IIIBI M MI Bl:

2 I I IoIB'S I I I I FIG.6

3 ZONE DELAY I56 m Q DOC EDGE TRAVEL DOCUMENT ADVANCE RATE TIME DELAYED FIRING NORMAL FIRING.

FIG.7

I60 D00 DDS 004 DDS 002 DDI BBO-/ B B B B B B 5I2I PATENTEB HAY 2 21975 SHEET 3 OF 4 PATENIEL m 2 2 1975 SHEET l [1F 4 200 v ZONE COUNTER MPA FIG.8

U u B CONVE D EM CLO CL no READY START DOC EDGE START DOCUMENT ENCODING APPARATUS CROSS-REFERENCE TO RELATED APPLICATIONS Reference may be made to the patent of Jack Beery and William B. Templeton, U.S. Pat. No. 3,659,524 and to the co-pending patent application, Ser. No. 812,006, filed Apr. 1, 1969, now U.S. Pat. No. 3,573,589 in the name of Jack Beery entitled POSI- TION SERVO SYSTEM FOR A MOTOR INCLUD- ING DETENTING AT DESTINATlON'and also to co-pending application, Ser. No. 68,135, filed Aug. 31, 1970 in the name of Richard M. Williams entitled EN- CODE PROGRAM SYSTEM, both of common ownership herewith.

BACKGROUND OF THE INVENTION This invention is directed to that field of art pertaining to the printing of data on unit records or documents as they are conveyed through a printing station or the like.

SUMMARY OF THE INVENTION An important object of the invention is to provide an improved control system for modifying the location of the areas on unit records upon which printed matter is to be added and while such record media are being successively fed along a transport path.

Another important object of the invention is to provide an improved control system as aforesaid which is self-operable to perform its area location modification by sensing the size of each unit record as' it is being transported and controlling the time when the printing operation is activated.

Another important object of the invention is to provide improved document encoding apparatus which is adjustable for accommodating documents having differently located encoding areas and for properly entering encoding data in such areas while the documents are in transit.

Another important object of the invention is to pro vide improved document encoding apparatus having the capability of entering printed matter in certain prescribed areas of rapidly fed documents and regardless of change in the location of said areas uponithe document.

In carrying out these objects, the present invention contemplates a printing apparatus which in its broader aspects and while a document is being transported senses the document and employs signals resulting from such sensing for modifying the operation of the apparatus so as to vary the location of printed matter added to each document as it continues along its path of transport.

More particularly, the invention contemplates a control circuit associated with a document encoding station through which documents, such as bank checks or similar media, are successively fed and receive printing impressions while moving at relatively high speeds. The encoding station includes a printing couple, such as a rotatable print wheel and print hammer, disposed to print on such record media as they are successively fed through the station and further includes a circuit for controlling the operation of the printing couple. The encoding station includes detectors positioned along the document transport path and on opposite sides of the printing couple which are included in the control circuit for determining the presence and the dimension of each document in the station and which utilizes signals resulting from such determinations for governing the action of the printing assembly. Included in the control circuit is means which, depending on the determined size of the document, can inhibit the operation of the print hammer so as to shift the areas of the document upon which character impressions are made, such means performing its operation as the document is advanced through the encoding station. Although the documents may differ in certain prescribed dimensions from one another, nevertheless minor variations may also occur which the control circuit can be adjusted to take into account. Accordingly, additional means is included in the control circuit which may further modify the locations of the encoding areas when such minor variations in the dimensions of the document are encountered.

The above listed objects and advantages, and other objects, advantages and aspects of the invention, will be more fully explained in the following detailed description. For a more complete understanding of the invention, reference may be had to the following detailed description in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a printing station diagrammatically illustrating the capability of the invention for en- -tering data on documents of different lengths in the form of bank checks;

FIG. 2 is a schematic diagram of a printing station illustrated in FIG. 1 but as viewed from the top thereof and showing in more detail the elements of the printing assembly and the location of the detection sensors with respect to the print wheel;

FIG. 3 is a side view of the apparatus illustrated in FIG. 2 but with certain parts removed for purpose of clarity;

FIG. 4 is a composit view illustrating in full and dotted outline two sizes of bank checks and displaying the aligned locations of the bank fields thereon and in projected larger scale the character encoding portions of each field;

FIG. 5 is a schematic diagram of a preferred circuit for accommodating documents, such as bank checks, of different predetermined lengths and for printing data in the prescribed field areas provided on the documents regardless of the lengths thereof;

FIG. 6 is a timing diagram illustrating a fine adjustment of the firing time of the encoding operation as the document is moved thereby;

FIG. 7 is an enlarged view illustrating the relationship of the delay in printing resulting in the accommodation of a larger document and the application of a fine adjustment in the vent the documents fail to meet the desired prescribed dimensions; and

FIG. 8 is a diagrammatic illustration of a preferred circuit for providing a fine adjustment to the encoding operation in the event the prescribed field areas are not properly related to the leading edge of the documents.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION The invention is illustrated herein as being applied to the entering of data in several fields of a financial document such as a bank check identified at 10, the titles of such -fields being separately identified in the order of the printing operation performed thereon by reference characters l2, l4, 16, 18 and 20. As illustrated in FIGS. 1 and 4 these banking fields are arranged in a row extending longitudinally of the bank check. Normally, the encoding data to be entered is printed below these respective field titles as indicated generally at 22 by a printing mechanism which, as illustrated herein, includes a reversely rotatable print wheel 24. The bank check is fed from left to right as viewed in FIGS. 1 and 4 so that the right hand edge 26 constitutes the leading edge of the check and the left hand edge 28 constitutes the trailing edge thereof. With this spatial arrangement of the banking fields on the check, it is evident that the field 12, which is nearest to the leading edge 26, is the first to receive encoding data therein.

With more particular reference to FIG. 4, the first of these fields, namely that indicated at 12, may be referred to as the Transaction Code or TC field which is usually four character positions long and identifies the type of document being processed. The second field may be referred to as the Routing or RT field which may have ten character positions for containing information for processing the document through a financial system. The third field 16 may be the Amount or AMT field for containing the money value of the document or check and for this purpose may be 13 character positions long. The fourth field 18 may be referred to as the Account Number or AN field and identify the payee or the account in which the check is drawn and as illustrated, it may contain 12 character positions therein. The fifth and last field 20 may be considered as the ON-US or AX field which is usually 14 character posi tions long and may contain information identifying the originating bank. Depending upon the use of the document 10, these encoding fields may be used to contain other information or be arranged in another order. Moreover, in certain foreign countries the field titles and the contents thereof may be different.

The document encoding system to be described hereinafter may be used to encode information on record members, such as bank checks, either in magnetic ink or in conventional ink but the characters so entered are shaped as to be recognized by a machine. More specifically, such printings may be in magnetic ink character recognition form, referred to'as MICR, or in optical character recognition form, referred to as OCR, depending upon the nature of the equipment for machine reading these characters. A desirable way of encoding this information in the separate fields of a bank check would be to print them with magnetic ink but in a font capable of being readily sensed by an optical recognition device, thereby enabling the printed characters to be machine read either magnetically or optically. Depending upon the manner in which the document is used, these fields may be utilized to contain information other than that intended for banking purposes. The system to be described herein provides means for assuring entry of the desired data in the proper field areas regardless of variation in the spatial location of these areas because of the resulting difference in the lengths of the documents being processed.

In dotted outline there has been superimposed on the bank check of FIG. 1, a second larger check identified at 30. If the leading edges of the two

checks

10 and 30 are made coincident as shown in FIG. 1, then the longer check 30 will have its trailing end portion projecting beyond that of the smaller check. Moreover, in

such uses to which these documents are put, the row of data entering field of the larger checks may be displaced further from the leading edge than the same row on the smaller checks. This is illustrated in FIG. 1 by the offset dotted outline of the several fields of the larger check and identified by the prime numbers 12,

14', 16, 18' and 20'. Although FIG. 1 shows the field titles of the larger check to be displaced vertically with respect to the field titles on the smaller check for purpose of explanation, it is to be understood that the titles of the banking fields as well as the data entry positions of the larger check would normally be on the same level as on the smaller check but displaced further from the leading edge than in the case of the smaller check.

The print wheel 24 is driven by a servo stepping motor, which may be of the character disclosed in the aforesaid referenced patent application Ser. No. 812,006 now U.S. Pat. No. 3,573,589, sothat it may be stepped and stopped at very fast rates and further can be stepped from one motor field position to the next and stopped without the armature over-throwing. FIG. 1 schematically illustrates the induction coils 32, 34 and 36 for rotating the print wheel, the coils being energized by a set of coil drivers (not shown) contained within a section of the system identified as 38 which, in turn, are controlled by a coil control section 40 shown in FIG. 1. As described in the aforesaid referenced application Ser. No. 812,006, the rotatable positioning of the print wheel 24 is determined by the control exercised over the coil drivers with the result that the selected type thereon is brought into print position at which time the wheel is stopped to receive the impact of a hammer disposed on the opposite side of the transport path along which the documents are fed. The print wheel may be adjustably rotated in either direction and the control circuits are so designed, as described in the aforesaid patent application Ser. No. 812,006 now U.S. Pat. No. 3,573,589, to rotate the wheel in the shortest direction to bring the selected type into printing position.

schematically illustrated in FIG. 2 is an encoding station or printer employing the type wheel 24 and showing the wheel disposed on one side of the path 42 along which a document, such as a bank check 10, is conveyed. For bank check encoding purposes the print wheel 24 may contain 15 characters identified at 44 around its periphery including the numerals 0 to 9" and several symbols. On the opposite side of the transport path 42 is a print impact member in the form of an interposer 46 mounted for movement in a plane perpendicular to the path 42 and intersecting the axis of the print wheel. The interposer is normally yieldingly retracted away from the document, such as by springs 47, but is capable of being impelled theretoward by the rocking movement of a lever type print hammer 48 arranged to strike the rear end of the interposer. The hammer is associated with an electromagnet generally indicated at 50 including a coil 52 surrounding a portion of a bar 54 of generally U-shaped configuration formed of magnetically permeable material, the bar being provided with a pivot pin 56 which serves to pivotally mount the remote end portion of the hammer 48. At least the remote end of the hammer is also composed of magnetically permeable material and cooperates with the bar 54 to form a substantially closed magnetic path including the portion surrounded by the coil 52. Thus, when the coil is energized it will attract the remote end of the hammer and cause its other end to swing in the direction to strike and impel the interposer against the document in the encoding station. The encoding unit further includes an inking ribbon 58 arranged by rollers for interposition between the type carrying periphery of the print wheel and the transport path along which the documents are advanced so that upon impact by the interposer a visual image of the struck type will be transferred to a document passing thereby.

Forming part of the document transport system are pairs of high speed document transport rollers located along the path of travel of the documents, two pairs of which are shown in FIG. 2 as being disposed close to and on opposite sides of the encoding station represented by the print wheel 24 and interposer 46. One pair of such rollers, indicated at 60, is upstream of the encoding station and the other at 62 downstream from the encoding station. As is the usual practice, one of each pair of rollers is a drive roller whereas the other is an idler roller making peripheral contact with the drive roller in the absence of a document therebetween and receiving driving torque therefrom in either case.

In the encoding station, but contacting one another just beyond the plane in which the interposer 46 operates, is a pair of pinch rollers, one of which serves as a drive roller and is identified at 64 and the other is an idler roller 66 which is engageable with the periphery of the driving roller for receiving torque therefrom. The driving roller 64, which is partially broken away to expose the interposer, is carried on the end of a drive shaft 65. The idler roller 66, however, is carried on an arm 68 which is yieldingly urged away from its companion driving roller 64 by spring tension (not shown). This spring tension is overcome by the action of a solenoid (not shown) which when energized acts on the arm 68 to movethe idler roller 66 into peripheral contact with either the driving roller 64 or a document passing therebetween. Actually, as shown in FIG. 3, the two

pinch rollers

64 and 66 may each have a coaxial companion roller vertically displaced therefrom and acting on a lower portion of the same document.

The two

pinch rollers

64 and 66 are tangentially disposed with respect to the document transport path and when in non-rotating contact with one another they will not allow a document to pass therebetween. When in non-rotating contact, the two rollers will therefore act as a limit stop to the progress of a document through the encoding station. However, when the drive pinch roller 64 begins to rotate it is designed to quickly reach a constant speed so that it will feed a document past the operating plane of the interposer 46 at this constant speed during which time the encoding operation is performed on the document. The driving speed of the pinch rollers is relatively considerably slower than the high speed of the

transport rollers

60 and 62 and others disposed along the path of travel, but because of the greater frictional characteristics of the peripheries of the pinch rollers, they will when in engagement with a document dominate the high speed transport rollers and will move it at a slower speed while the transport rollers also engaging the document will function ineffectually to drive it at a faster rate. At the conclusion of the encoding operation on a particular document passing through the encoding station, the solenoid for the idler pinch roller is de-energized enabling the spring tension acting on the idler roller 66 to pull it away from its companion drive roller 64 and thereby permitting the high speed set of transport rollers 62--62 to take over control of the document and move it at a substantially faster rate further along the transport path.

Also included as control elements associated with the encoding station are document sensors in the form of photodetection devices arranged along the path of travel through the station. As shown in FIGS. 1, 2 and 3, one such sensor is positioned at 70 slightly above the print wheel and slightly downstream of the line of contact of the two

pinch rollers

64 and 66. A second and third of

such photodetection devices

71 and 72 are located in the vicinity of the pinch rollers, the former functioning in the operating plane thereof, and close to the bottom edge of a document transported through the station. A fourth photodetection device 74 is positioned upstream of the interposer 46 and generally in the vicinity of the pair of high speed rollers 60-60.

The first of these detection devices, namely that identified at 70, serves as a leading edge detector for sensing the passage of the leading edge 26 of a document. The second and third of these

devices

71 and 72 serve to indicate the arrival of a document between the pinch rollers and to determine whether or not the lower edge of the document in the encoding station is undamaged and properly aligned so as to feed through the station in unskewed condition. The fourth photodetection device 74 is located remote from the others and sufficiently upstream thereof that for the shorter-sized document 10 the trailing edge 28 thereof would have passed thereby at the time the leading edge 26 intercepts the

skew detectors

71 and 72. This is illustrated in FIGS. 1 to 3 where the shorter check shown in full line representation has its trailing edge 28 to the right of the detector 74. However, for the longer or larger size documents represented by that shown at 30, the trailing edge portion thereof would still overlap and therefore still obstruct the sensor 74 at the time the leading edge 26 of the docuinent intercepts the

detectors

71 and 72. As will be hereinafter described, control circuit means embodying features of the invention utilize the two conditions presented by shorter and larger documents as each enters the encoding station for controlling the printing of data in the several field areas of the document. 1

Included as additional operating elements of the encoding station is an electromechanical clock generator for producing pulses in timed relation to the movement of the document therethrough and a clutch for disengagingly coupling the drive pinch roller 64 to a power source. With'reference to FIG. 3, the clock generator may take the form of a toothed wheel 76 fixed to shaft 64 and a magnetic sensing head 78 mounted adjacent to the wheel and operable to produce a pulse each time a tooth of the wheel passes thereby. This generator is designed to provide eight'pulses for each character position of the document fields and thus dividing each character position into eight zones. Ultimately, these zone signals are received by a zone counter 200 to be more particularly described hereinafter. Rotational drive of the shaft 65 is controlled by a spring clutch schematically illustrated at 80 which may be activated by a solenoid (not shown). It is evident from the disposition of the generator and the cluthh that the former is only operative in these circumstances when the clutch is engaged and the pinch rollers 64-66 are operating to advance the document through theencoding station at relatively low speed.

As illustrated in FIG. 4, the document format concerning the

several printing fields

12, 14, 16, 18 and 20 have their respective boundaries delineated by certain symbols including B for signifying a blank and other special symbols for the machine reading of the entries. As described in the aforesaid application Ser. No. 68,135, the special symbols may be controlled by a patchboard 82 shown in FIG. 5. The composite view of FIG. 4 illustrates in its larger projected scale each character position of the several fields of the document including the boundary symbols. One or more of the fields on the documents shown in FIGS. 1 and 4 may be employed for entering data and the beginning end of each such field may be delineated by the printing of an appropriate symbol in the manner previously described. Field identified at 12 will begin with the symbol 84, a chair, encoded in the first digit position. Its fourth or last digit position will end as a blank B. Field 1, identified at 14, will begin its first digit position with a second symbol 86, a hook, and will end with a blank symbol B at position 10. Similarly, the remaining

fields

16, 18 and 20 of the check will begin and end at their respective boundaries and contain different numbers of character positions into which the data entries may be made. Usually, a number entered into each field will occupy less than the total number of character positions therein. Such numbers will be entered into the right section of their respective fields, and all remaining character positions of these fields will be zero filled to their respective left boundaries.

When a document is transported into the encode station it is stopped by the engaging but non-rotating pinch rollers 64-66 as previously described. However, in this position its leading edge intercepts the

skew detection cells

71 and 72 and this interception may be used to produce a signal which energizes the solenoid controlling the spring clutch 80 causing it to couple the drive pinch roller 64 with a source of power. When so coupled, the pinch rollers quickly accelerate to a constant speed and will move the document at this constant but relatively slow rate through the encode station. After the document has moved approximately oneeighth inch, the leading edge 26 will intercept the photodetection cell 70 which as shown in FIG. 1 is slightly downstream from the cell 72. The signal produced by this interception will allow the equally spaced apart pulses from the clock generator 76-78 to function as control signals for regulating the print wheel motion and the firing of the printing elements.

At this time in the operation of the system, the document

skew detection cells

71 and 72 and the document trailing portion detection cell 74 cooperate to determine the size of a document introduced into the encoding station. As previously described, and as illustratively portrayed at the left of FIG. 5, a shorter document covers only the

skew cells

71 and 72 if properly aligned but not the trailing edge cell 74 thereby signifying that a smaller size document or bank check has entered the encoding station. However, as also illustrated in FIG. 5, a larger document 30 will cover all three of the

photodetectors

71, 72 and 74 at the time the leading edge of this larger document intercepts the skew cell 71.

The logic of the control system employed in the schematic circuit diagrams illustrated in FIGS. 5 and 8 basically use NAND gates wherein the output is true if any one or more of the inputs of the gates are false. All flip flops are to be considered as J-K flip flops and will be negative triggering flip flops. A negative triggering signal is defined as one going from a positive voltage condition to a voltage condition which is more negative. On all J-K flip flops having a signal connected to the trigger input thereof, the switching of the flip flop will be controlled by the triggered signal.

In the illustrated system, encoding is a digit by digit operation. The information to be encoded on the document is withdrawn from the memory of the apparatus and particularly from selected storage registers and transferred digit by digit to an encode register where it is used to position the print wheel 24, in the manner described in the referenced patent application Ser. No. 812,006 now U.S. Pat. No. 3,573,589. The encoding is under the control of the previously referred to symbol control unit or patchboard 82, a digit control or distributor unit 88, and a field control unit 90. The last is basically a ripple counter which counts from zero through four and resets, and in this manner keeps track of each of the five fields entered on each document, returning to zero to start over again on the next succeeding document. The digit control distributor 88 is composed of a plurality of serially connected flip flops arranged as a ripple-type counter for counting digit positions from zero through and including digit 15. The digit distributor 88 is synchronized with the rotational drive of the pinch rollers and is a four stage flip flop counter which is decoded in a binary to decimal decoder generating sixteen unique output positions DDO through DDIS.

As will be more particularly described hereinafter, when a document 10 is ready to be encoded, an encode ready signal is generated which performs the function of allowing the field control unit 90 to count and also the function of connecting the drive through the spring clutch 80 for rotating the pinch roller 64. For this purpose, the leading edge photodetector is employed and when so tripped by the leading edge of the document it starts the counting function of digit control unit 88. It is thus apparent that the digit control unit 88 is synchronized with the rotation of the pinch rollers and their control over the movement of the document through the encoding station. When the DB0 signal is logically true, the symbol output of the patchboard is activated and the encoding wheel 24 responds by printing the first symbol 84, a chair, in the first character position of field 0.

Once the pinch wheel drive roller 64 is clutched to the power source, it is brought up immediately to a constant rotating speed, generating the timing signals for the digits control distributor 88 and causing it to initially step from DDO to DD1 and then from DD1 to DD2. Because the symbol output from the patchboard is false for DD1 and DD2, the output of the memory of the apparatus is enabled and is gated to encode the intended data into the second and third character positions of field 0 of the document. The stepping of the digit distributor continues until digit DD3 is reached, which is position four of field 0, at which time, as indicated on the patchboard, it is wired to a blank B. When a blank B is drawn from the patchboard, it signifies a non-encode operation and as described in the aforesaid reference patent application Ser. No. 68,135 it will inhibit the firing of the hammer 48 and the operation of v the print interposer 46 with the result that no printing occurs in this position. The first field is four positions long, as previously recited herein, and when the fourth character position has been accounted for an end of the field signal is gated to the field counter 90 so that it now shifts from field 0 to field l and digit control unit 88 resets from digit signal DD3 to DDO. As the result, the beginning symbol of field 1, namely the hook 86, is caused to be printed on the document to signify the beginning of this field. The encode operation continues throughout the remaining fields of the document employing the symbols and the blanks to signify the beginning and end of each field. At the conclusion of the last field, the

pinch rollers

64 and 66 are separated by lateral displacement of the latter with the result that the high speed transfer rollers 62-62 now take over control by the movement of the document and drive it out of the encoding station at high speed. As previously mentioned, the unit encoding of data in a given field usually occupies less than the total number of character positions so that all character positions to the left of the entered data are filled in with zeros.

It will be apparent from the circuit shown in FIG. that for the entry of a small size document into the encoding station, skew

detectors

71 and 72 are in a covered and thereby non-excited state whereas the trailing detector 74 is not covered and is therefore in its excited state. Since two of the three inputs to the NAND gate 100, namely 71/ and 72/ are true and the third 74/ is false, the output of the gate is true. This state is inverted by NAND gate 102 whose output 104 forms the input to NAND gate 106. Assuming the presence of a timing signal on input 105 of gate 106, which signifies the system is ready to start the encode operation, the NAND gate will be enabled and its output signal will be false. This condition will be inverted to true by NAND gate 108 whose output forms one input to a flip flop 110. The flip flop 110 is normally reset to indicate this true condition as evidenced by its output 112 which enters NAND gate 114 together with the input represented by the legend start upon which a signal is induced during the time the pulse generator 76-78 is rendered operable. The output of NAND gate 114 is inverted by gate 116 sothat the normal field signal to NAND gate 118 associated with the patchboard 82 is true. Thus, upon receipt of a DDO digit signal upon input 120 the encoding wheel is rotated to present the character 84, a chair symbol, for printing in the first character position of field 0. The result of this operation is shown in the fragment of document 10 at the right end of FIG. 5. The several character positions of field 0 are numerically indicated from right to left by

numerals

0, 1, 2 and 3, and as indicated in the fragmentary portion of the document the chair symbol 84 has been entered in position 0 in close proximity to the leading edge 26.

In the event, however, a larger document or bank check 30 is introduced into the encoding station, the three

photodetectors

71, 72 and 74 will be covered thereby, as exemplified in small scale at the left end of FIG. 5, with the result that all signals on NAND gate 100 are true so that its output is false. Being reversed to that for the shorter document this false state will in its transit through the several NAND gates to the flip flop l 10 end up as a true signal causing the latter to be set and provide a true signal on its output 122. This signal together with the start signal by way of channel 124 enables NAND gate 126 to provide a false output which is then reversed by the gate 127 to true on input 128 to NAND gate 130 of the patchboard 82. The other input to NAND gate 130, namely channel 132, forms the output of NAND gate 134 which receives six successive digit inputs represented by DDO/, DDll, DD2/, DD3/, DB4] and DDS/ which are connected to like outputs of the digit distributor 88. The logic of the circuit is such that as each of the signals DDO/ to DD5/ from the digit distributor are successively fed to the NAND gate 134 each signal produces a true signal on output 132 with the result that by virtue of the patchboardconnection 136 the firing of the hammer is inhibited thereby producing a blank space B on each of the first six character positions of the document 30.

These six character positions are illustrated in the fragment of document 30 illustrated at the right end of FIG. 5 where the representation B simply means the absence of any printing in the enumerated character positions one to five appearing in the row therebelow. In other words, for this particular larger-sized document 30, six firings of the print hammer were inhibited as six character positions of the document passed by the interposer 46 with the result that a predetermined greater distance extends between the leading edge of the larger document and the first character position of field 0 thereof.

The circuit, however, is designed so that after the gate 134 receives the DDS/ signal from the digit distributor, the flip flop 110 is reset so as to assume its normal state. For this purpose, a reset circuit is provided comprising a NAND gate 140 having three inputs, an input 142 connected through channel 124 to the start signal input previously referred to, an input 144 connected to the DDS output of the digit distributor 88, and a third input 146 for receiving an input signal signifying the document extension operation. The output of gate 140 is connected through channel 148 and

NAND gates

150 and 152 to reset side of the flip flop 110 and serves to trigger the reset on the negative transition of the clock pulse received on input 156. When this occurs, the digit distributor 88 is also set back to DDO position. Because the beginning of a field on the document is now presented to the circuit, which position is signified by a DDO, the first symbol for such field, in this instance field 0, is printed upon the document. Since DDO is now called for, the symbol 84, a chair, is printed as a first character on the document. Comparison of the two fragments of the

documents

10 and 30 at the right of FIG. 5 will show that the incapacity to print in any of the six blank positions of the large document brings the printing of its first character in field 0 in alignment with first character in field 0 in the shorter document. As a result, data will be properly entered into field 0 and all remaining fields of the larger document 30 just as if it was a smaller size document 10.

The circuit of FIG. 5 has been described herein as applied to the automatic sensing of the document sizes and the operation of certain circuit components for determining the spatial location of the encoding format on the document in accordance with the determined size of the document. An automatic operation of this character is desirable where the documents of different sizes are intermixed. However, when batches of documents of one size are to be fed through the encoding apparatus the operator may set the circuit to operate with this particular size of document. This is accomplished in the manner shown in FIG. 5 by a manual switch, one position of which would cause the circuit to encode on the smaller size documents and the other position of which would cause the circuit to encode on the larger size documents. Such a switch, shown in FIG. at 158, is connected into the input 104 of NAND gate 102 in overriding relation to the NAND gate 100 and is operable in closed position to ground this input and cause the circuit to encode only for larger size documents 30 and providing the blank extension to the leading portion thereof. In the opened position of the switch 156 the circuit will function normally to handle a batch of smaller size documents and encode thereon in a manner previously described.

As earlier mentioned herein, the clock generator 76-78 produces pulses in timed relation to the movement of the document, which pulses are at a frequency such that in the herein described embodiment of the invention they will divide each character position into eight zones. These eight signals are utilized by the zone counter 200 to be more particularly described hereinafter for timing the operation of the printing elements for printing each individual character on the moving document. For example, zone signals zero to three may be used to position the print wheel, zone signal six to lock the print wheel, and zone seven to fire the print hammer. Advantage is taken of the zone signals for providing a fine adjustment of the printing mechanism in order to accomodate any slight irregularity in the dimensions of the documents upon which the encoding operation is performed. Occasionally, batches of bank checks will be found, which, although all of the same size, will vary slightly from a prescribed dimension and result in a slight shift in the encoding of characters in the print areas 12-20 of the document. In a multiple sheet form of banking document, to be more particularly described hereinafter, one or more lines of weakness are provided for tearing off marginal end portions but retaining and using the large central area containing the encoded data and other information. Misplacement of these lines of weakness may raise difficulties in subsequent machine reading because the starting point of the row of encoded data with reference to the newly created leading edge will differ from the prescribed distance therefore.

FIGS. 6 and 7 describe the purpose of the desired fine adjustment of the encoding operation when dimensional irregularities of these characters are encountered and FIG. 8 discloses the circuitry for accomplishing this adjustment. Since each character position can be divided into equal multiple increments, in this case eight zones by the pulse generator 76-78, one or more of these pulses may be used by the adjustment provision to be described for delaying the firing of the print hammer and its interposer so as to shift the printing of the characters in the designated areas 12-20 anywhere from one-eighth to seven-eighths of a character position. For example, FIG. 6 illustrates the superimposition of three zone delays upon the normal operation of the print hammer on a smaller size check 10. As earlier explained herein, the first print operations on each bank check entering the encoding station is the chair seventh zone of the first character position as indicated by the chart in FIG. 6, but because of the imposition of a delay of three zones to accommodate a batch of slightly oversized documents the timing of the firing has been adjusted to occur three zones later or at the 10th zone signal as received since the leading edge of the document intercepted leading edge sensor 70.

FIG. 7 illustrates a delay in firing caused not only by the addition of six blank character positions in advance of the chair symbol 84 for a larger document 30 but also by the addition of a fraction of a character position represented by the narrow box 160. This fractional extension of the delay represented by the delta symbol, takes advantage of the zone pulses derived from the pulse generator 76-78. As in FIG. 6, three of these zone pulses are employed in this example to add the slight supplemental extension onto the larger extension represented by the six blank character positions.

In certain countries multi-sheet document assemblies are used for individual bank checks, and by virtue of interleaved carbon sheets the encoding data is printed not only on the top sheet of an individual check assembly of this type but also printed on the remaining sheets of each assembly in order to provide several copies of the check. Multi-sheet bank check forms of this kind usually require a removable and tab portion at one or both ends of the assembly for temporarily securing the sheets of the assembly together at least until the encoding operation is performed, after which the tabs are usually removed or torn off in order to separate the bank check copies from one another. A check of this form may be exemplified in FIG. 4 if the two end extensions of the larger check 30 beyond the smaller check 10 are considered as the removable tab portions serving, before removal, to secure several layers or sheets together into packet for the earlier part of the commercial transaction and later removed after the encoding operation. In other words, the area represented by the smaller check 10 in FIG. 4 also constitutes the reduced size of the larger check 30 after removal of its two end portions.

To facilitate severing of these two tab portions, the larger check 30 is provided lines of weakness or perforations which in FIG. 4 would coincide with the leading and trailing edges of the smaller check 10. However, in providing these lines of weakness for severing purposes, they should be precisely laid down on the larger check 30, otherwise when the tabs are removed from the larger check, the machine reading of the original and carbon copies thereof may be erroneous. This is likely to occur if the characters of the encoded data do not properly register with their assigned character positions on the check. The adjustment provision of FIG. 8 enables the operator to examine a sample check of a batch of initially larger checks 30 and after removing the tab portions from the sample determining with the use of a bank check gauge whether the distance between the new leading edge and the first character 84 in field 0 is precisely that required by banking regulations. If not, a measured fractional adjustment performed by the circuit of FIG. 8 will enable the operator to properly encode on the balance of the checks of this batch so that subsequent machine reading will be accurate.

Referring more specifically to FIG. 8, the circuit in general comprises an operator control switch generally indicated at 162 having a handle 164 which is normally set at the position but which is movable through one to seven decimal positions each representing a different one of the seven remaining zone pulses produced by the pulse generator 76-78 for each character position. The output of the switch as determined by the switch handle is fed to a decimal to binary converter indicated at 166 whose output signals S1, S2 and S4 are connected to a comparator 168.

In the lower portion of FIG. 8 there is shown a delay counter represented by the flip flops C1, C2 and C4 which are serially connected together in a conventional manner and receive signals on channel 170 originating from the electromechanical pulse generator 76-78 (EM clock), such signals being conveyed to

NAND gates

172 and 174 and to the first flip flop of the counter. A signal from an encode interlock flip flop (EIF) is also received by the delay counter on input 176 which is conveyed through NAND gates to the separate flip flops of the counter for signifying that the encode operation is in effect and enabling the flip flops of the counter, the signal being high for encoding and low during the time when encoding operation is not to be performed.

Inputs

180 and 182 to NAND gate 184 provide ready start and document edge starting signals respectively to the circuit of FIG. 8. When both inputs are true the output signal of NAND gate 184 is false but re-inverted to true state by NAND gate 186 with the result that the input 188 to NAND gate 190 is true. If the switch 164 is adjusted to its normal zero position, the fine adjustment circuit of FIG. 8 merely compares the zero setting of the control 162 with the zero reset condition of the delay counter represented by the flip flops C1, C2 and C4 and therefore no delay is imposed in the action of the zero counter. However, if the switch 164 should be shifted to any one of the decimal numerals 1 through 7, then the input 192 to NAND gate 190 would be true only when the comparator determines that the count of the pulses received from the delay counter by way of channel 194 matches the number to which the switch handle 164 has been turned. When this occurs, the inputs to the NAND gate 190 will'both be true providing a false signal on its output which in turn is inverted by NAND gate 196 to a true condition on the input 198 to the zone counter 200 which as previously described regulates the timing of the operating elements of the encoding printer. The zone counter is enabled by a true signal on input 196 causing it to start counting repetitively from zero to seven, reset and count again from zero to seven, et cetera. In this manner the zone counter feeds signals timed to the movement of the document for controlling the operating elements of the printing station so that during the passage of each character position on the document past the interposer 46 the print wheel is rotated to bring the selected character into the print position and detented in such position and thereafter the print interposer impacts the document against the selected character.

At the time a false signal occurs on the output of NAN D gate 190, this condition is transmitted by channel 202 to input of NAND gate 204, the output of which is connected to NAND gate 206, and thence to the input of the delay counter flip flops between

NAND gates

172 and 174. The receipt of this condition, which reflects the start of the zone counter 200, will inhibit further activity on the part of the delay counter.

It is evident from the above description that two control circuits have been described for controlling the operation of the printing couple, such as represented by a print wheel 24 and the print hammer 48, and for modifying the commencement of its printing operation on a document passing through the encoding station. One such circuit provides a relatively coarse adjustment, in this instance, six inhibited or blank character positions when a larger document is passed through the station,

and the other a relatively fine adjustment of the printing operation representing a fractional portion of one character position on the document. The circuit of FIG. 5 provides the first of such adjustments and the circuit of FIG. 8 provides the second. The two control circuits exercise their respective controlling actions over the operating elements of the printer and are relatively independent of one another. That is to say, one control circuit may be used while'the other is not and vice versa, and both may be employed to control the operation of the encoder as exemplified by the schematic illustration in FIG. 7.

It is believed that the operation of the apparatus is clearly apparent from the hereinabove description. In one embodiment of the invention, the document is moved through the encoding station at a rate of 2.5 inches per second and when the leading edge of the document intercepts the detector 70, the encoder timing logic provided by the zone counter is started. The encoding timing is kept in synchronization with the advancement of the document by the electromechanical clock 76-78. In this embodiment, it will take each character position on the document 50 milleseconds to move past the print wheel interposer hammer 46, and this represents the time allowed for each character to be processed and printed. The sequence of accessing digits from the memory of the apparatus, positioning of the print wheel and the firing of the hammer continues as the document moves through the encoder station. If a character is not to be printed, one or more blank signals are produced which prevent the hammer from firing in zone 7 of each character position. The control circuit of FIG. 5 utilizes one or more whole character positions to provide the desired adjustment for documents of different sizes. The control circuit of FIG. 8 utilizes a fractional portion of one character position represented by one or more of the seven zones into which it is divided by the zone counter to provide the desired relatively fine adjustment.

While a particular embodiment of the invention has been shown and described, it will be understood, of course, that it is not desired that the invention be limited thereto since modifications may be made, and it is, therefore, contemplated by the appended claims to cover any such modifications as fall within the true spirit and scope of the invention.

What I claim is: i

1. Apparatus for printing on record members of at least two different lengths each having a series of areas displaced lengthwise of the record member and representing different encoding fields or the like, the combination of which comprises:

a printing station and means for serially feeding such record members field-by-field through the printing station, said printing station including printing mechanism for printing on said field areas as they pass thereby,

first detection means on the downstream side of the printing mechanism for sensing the presence of the record member and so positioned with respect to the printing mechanism as to signify the passage of the leading edge of such record members thereby in advance of the passage of the first field area past the printing mechanism,

second detection means positioned on the upstream side of the printing mechanism for sensing the presence of the trailing portion of only the longer of such record members,

control circuit means coupled to said first and second detection means and including means responsive to the sensing of such a record member by only the first detection means for providing a first signal signifying the passage of a shorter one of such record members and responsive to the coincident sensing of such a record member by the first and second detection means for providing a second signal signifying the passage of a longer one of such record members, and

said control circuit means further including means responding to said first and said second signals and being operable to commence the printing of said first field area at one distance from the leading edge of such a record member when said first signal only is received and to commence the printing of said first field area at another distance from the leading edge of such a record member when said second signal is received.

2. Apparatus as defined in claim 1 characterized in that said last mentioned means is effective to commence the printing of the first field area at a shorter distance from the leading edge of such record member when the said first signal is received and at a greater distance from the leading edge of such a record member when the said second signal is received.

3. Apparatus as defined in claim 1 characterized in that said feeding means advances the record members at a constant rate past the printing mechanism, and further characterized in that means is provided for operating the printing mechanism in timed relation to said constant rate of advance.

4. In combination with a printing station including means for serially feeding record members of varying lengths therethrough having lengthwise extending series of encoding fields each divided into a plurality of character positions for the entry of printed characters, and further including a printing couple composed of a rotatable print wheel and cooperating print impact member for entering characters into the character positions of the encoding fields of each such record member as it passes thereby,

first detection means on the downstream side of the printing wheel for sensing the presence of such a record member and so positioned with respect to the printing wheel as to signify the passage of the leading edge of such record member thereby in advance of the passage of the first of said series of encoding fields past said printing couple,

second detection means positioned on the upstream side of the printing couple for sensing the presence of the trailing portion of such a record member passing through the printing station,

means coupled to said first and second detection means andresponsive to the sensing of such a record member by only the first detection means for providing a first signal signifying the passage of a shorter one of such record members and responsive to the concurrent sensing of such a record member by both the first and second detection means for providing a second signal signifying the passage of a longer one of such record members, and

a control circuit responding to the receipt of said first and second signals for causing the printing couple to print characters in the first of said series of encoding fields at one distance from the leading edge of such a record member when said first signal only is received and for causing the print couple to print characters in the first of said series of encoding fields at another distance from the leading edge of such a record member when said second signal is received.

5. The printing station as defined in claim 4 characterized in that the control circuit includes means for delaying the printing action of the print couple upon such a record member being fed therethrough for a certain number of character positions when said second signal is received.

6. The printing station as defined in claim 4 characterized in that means is included in the control circuit for inhibiting the printing action of the printing couple upon such a record member being fed through the printing station for a fractional portion of a character position of the record member.

7. In apparatus for printing data along a line of adjoining equal-sized character positions extending lengthwise of a document;

a printing couple including a movable print member carrying type characters and a cooperating hammer member operable to impact a selected type character after the print member has been moved to present the type character for printing, said members of the printing couple being disposed on opposite sides of a transport path;

means for serially advancing documents at a constant rate along that portion of the transport path extending between the two members of the printing couple;

means for coordinating the operation of the printing couple in timed relation to the advance of a document therebetween and producing a plurality of clock signals during the time interval required to prepare and print each character for governing the action of the operating elements of the printing couple;

detection means positioned in downstream relation of the printing couple for sensing the passage of the leading edge of a document thereby and producing a signal when such occurs;

circuit means coupled to said detection means and responsive to its signal for causing the printing couple to commence the printing of said line on the document at a given distance from the leading edge thereof, and

a control circuit coupled to said operation coordinating means to receive said clock signals and including means for varying the starting point of the printing operation performed by the printing couple on said line of a document by changing the number of said clock pulses utilized for printing the first character of said line.

8. Apparatus as defined in claim 7 characterized in that the control circuit utilizes the clock signals for inhibiting the printing action of the printing couple for a fractional portion of one character position so that the printing couple is caused to commence the printing of said line at an equivalent greater distance from the leading edge of the document.

9. Apparatus as defined in claim 8 characterized in that said control circuit includes a control member selectively movable to any one of a plurality of positions each representative of a different number of the clock signals and further includes a comparator for matching the selected number of clock signals against those received by the control circuit.

10. In printing apparatus having cooperative elements disposed on opposite sides of a document transport path to form a printing couple effective to print a single character at a time on a document disposed therebetween, and including means for uninterruptedly advancing documents serially along the transport path between the elements of the printing couple and including further means for actuating the elements of the printing couple while each such document is advanced uninterruptedly therebetween to print a row of characters on the moving document,

means for producing electrical pulses in substantially timed relation to the uninterrupted movement of each document through the printing couple, the frequency of the pulses produced by said producing means being so related to each character being printed by said printing couple as to produce a plurality of pulses during the time interval needed to prepare a selected character for printing and to print such selected character,

means for receiving the pulses produced by said pulse producing means and operable to assign a group of such pulses to each character selected to print on the document and to utilize such an assigned group of pulses for controlling the operation of the cooperative elements of the printing couple to print the character on the moving document, and

means for introducing one or more pulses into the pulse group assigned to a character selected for printing to shift the print position of such character in the row being printed on the document.

11. Printing apparatus as defined in claim 10 wherein detection means is provided for determining a dimensional characteristic of each document fed through the printing couple and wherein further means is provided for selecting the location of the character to be printed on the document in accordance with this determination.

12. Printing apparatus as defined in claim 10 wherein said detection means includes a detector for sensing the leading edge of a document introduced to the printing couple and further includes a second detector for concurrently sensing the presence or absence of the trailing edge portion of the same document.

13. Printing apparatus as defined in claim 10 wherein the pulse introducing means acts to delay the printing of the character associated with the pulse group into which one or more pulses have been introduced, the extent of the delay being determined by the number of pulses introduced into the group.

14. Printing apparatus as defined in claim 10 wherein means is provided which is operatively coupled to said pulse introducing means for controlling the same and which includes a control member selectively movable to any one of a plurality of positions each representative of a different number of the clock signals and further includes a comparator for matching the selected number of clock signals against those received by said pulse receiving means for assignment as a pulse character to a character selected for printing.

Claims

1. Apparatus for printing on record members of at least two different lengths each having a series of areas displaced lengthwise of the record member and representing different encoding fields or the like, the combination of which comprises: a printing station and means for serially feeding such record members field-by-field through the printing station, said printing station including printing mechanism for printing on said field areas as they pass thereby, first detection means on the downstream side of the printing mechanism for sensinG the presence of the record member and so positioned with respect to the printing mechanism as to signify the passage of the leading edge of such record members thereby in advance of the passage of the first field area past the printing mechanism, second detection means positioned on the upstream side of the printing mechanism for sensing the presence of the trailing portion of only the longer of such record members, control circuit means coupled to said first and second detection means and including means responsive to the sensing of such a record member by only the first detection means for providing a first signal signifying the passage of a shorter one of such record members and responsive to the coincident sensing of such a record member by the first and second detection means for providing a second signal signifying the passage of a longer one of such record members, and said control circuit means further including means responding to said first and said second signals and being operable to commence the printing of said first field area at one distance from the leading edge of such a record member when said first signal only is received and to commence the printing of said first field area at another distance from the leading edge of such a record member when said second signal is received.

4. In combination with a printing station including means for serially feeding record members of varying lengths therethrough having lengthwise extending series of encoding fields each divided into a plurality of character positions for the entry of printed characters, and further including a printing couple composed of a rotatable print wheel and cooperating print impact member for entering characters into the character positions of the encoding fields of each such record member as it passes thereby, first detection means on the downstream side of the printing wheel for sensing the presence of such a record member and so positioned with respect to the printing wheel as to signify the passage of the leading edge of such record member thereby in advance of the passage of the first of said series of encoding fields past said printing couple, second detection means positioned on the upstream side of the printing couple for sensing the presence of the trailing portion of such a record member passing through the printing station, means coupled to said first and second detection means and responsive to the sensing of such a record member by only the first detection means for providing a first signal signifying the passage of a shorter one of such record members and responsive to the concurrent sensing of such a record member by both the first and second detection means for providing a second signal signifying the passage of a longer one of such record members, and a control circuit responding to the receipt of said first and second signals for causing the printing couple to print characters in the first of said series of encoding fields at one distance from the leading edge of such a record member when said first signal only is received and for causing the print couple to print characters in the first of said series of encoding fields at another distance from the leading edge of such a record member when said second signal is received.

7. In apparatus for printing data along a line of adjoining equal-sized character positions extending lengthwise of a document; a printing couple including a movable print member carrying type characters and a cooperating hammer member operable to impact a selected type character after the print member has been moved to present the type character for printing, said members of the printing couple being disposed on opposite sides of a transport path; means for serially advancing documents at a constant rate along that portion of the transport path extending between the two members of the printing couple; means for coordinating the operation of the printing couple in timed relation to the advance of a document therebetween and producing a plurality of clock signals during the time interval required to prepare and print each character for governing the action of the operating elements of the printing couple; detection means positioned in downstream relation of the printing couple for sensing the passage of the leading edge of a document thereby and producing a signal when such occurs; circuit means coupled to said detection means and responsive to its signal for causing the printing couple to commence the printing of said line on the document at a given distance from the leading edge thereof, and a control circuit coupled to said operation coordinating means to receive said clock signals and including means for varying the starting point of the printing operation performed by the printing couple on said line of a document by changing the number of said clock pulses utilized for printing the first character of said line.

10. In printing apparatus having cooperative elements disposed on opposite sides of a document transport path to form a printing couple effective to print a single character at a time on a document disposed therebetween, and including means for uninterruptedly advancing documents serially along the transport path between the elements of the printing couple and including further means for actuating the elements of the printing couple while each such document is advanced uninterruptedly therebetween to print a row of characters on the moving document, means for producing electrical pulses in substantially timed relation to the uninterrupted movement of each document through the printing couple, the frequency of the pulses produced by said producing means being so related to each character being printed by said printing couple as to produce a plurality of pulses during the time interval needed to prepare a selected character for printing and to print such selected character, means for receiving the pulses produced by said pulse producing means and operable to assign a group of such pulses to each characteR selected to print on the document and to utilize such an assigned group of pulses for controlling the operation of the cooperative elements of the printing couple to print the character on the moving document, and means for introducing one or more pulses into the pulse group assigned to a character selected for printing to shift the print position of such character in the row being printed on the document.