1. Field of the Invention:

This invention relates to the field of printing apparatus operable to produce visible imprints of characters or codes using a print mechanism which forms characters using one or more discrete elements or discrete element positions which are selectively activated and thereby combined to place characters on a form. In particular the invention concerns such a printer wherein an optical mark sensor is provided on the printing apparatus to test for faulty operation of the character forming elements by scanning previously printed lines.

2. Prior Art;

Printers having movable printing means or fixed printing means in combination with form advancing feed mechanisms are well known. For example, a movable printing head can be passed along a print line while selectively operating individual ones of a plurality of elements for forming dots, segments or other portions which together define characters. The elements are activated in time coincidence or form-position coincidence with a stored character font or the like, such that the characters are placed on the form. In a movable carriage arrangement the characters can be formed in one or more passes laterally or longitudinally relative to the form. Alternatively the form can be moved relative to fixed printing elements, whereupon the elements are selectively activated in time or position coincidence to provide the characters across the width defined by the elements and along the relative path of the form. A feeding mechanism advances the form line by line and/or advances the printing elements to print successive alphanumeric character text, bar code or other symbols.

In a dot matrix printer, a pattern of impact pins, ink jet droplet positions, laser dot formation positions or the like are selectively operated to form the characters or symbols by darkening a pattern of individual dots. Similarly, in numeric seven segment printers and in alphanumeric segment printers, a plurality of discrete segments form the characters or symbols. For any of these

printers, the actual formation of the characters can be accomplished using heated surfaces on thermal paper, impacts against ribbons or impact-sensitive paper, gating of ink jet mechanisms or laser light, etc.

It is possible that the apparatus for forming dots or segments or the form or carriage feed may fail, and the failure may be so limited as to affect only certain of the discrete printing elements or only certain of the characters. Potential failures could occur in mechanical movements, electrically changeable elements such as heated segments or piezoelectric devices, or in the decoding or driving circuits. When this occurs, it is possible for alphanumeric characters which are formed by the printer to appear to be accurate, when in fact they are erroneous. If an intended alphanumeric character includes a horizontal or vertical line, a failure of the pin, segment, ink jet or other element which is to form the line in conjunction with relative displacement of the form and the element, may cause formation of a character which at least upon brief inspection appears to be a different character than was intended and attempted to be formed by the printer and its control circuitry. For missing horizontal lines, for example, a seven may appear to be a one or a slash; a two may appear to be a seven; a five may appear to be a zero, etc.

Where the characters are formed by seven segment print elements, for example as are common in thermal printers, loss of one segment can convert a seven to a one, or a six to a five. Loss of two segments can convert zero or three to seven, four to one, eight to nine or three, and so on. Moreover, if one of these failures occurs in a seven segment printer, the erroneously formed characters are optically indistinguishable from characters which are printed correctly by the printer. Similar errors are possible in other forms of printers wherein a plurality of discrete elements are operated in conjunction with relative displacement between the elements and the form (either or both being movable).

Errors of the foregoing type are serious problems in the printing of alphanumeric characters which will be relied upon to indicate data associated with a transaction. Printing on lottery

entry tickets and the like are one example. Where the apparent printed entry numbers happen to be winning entries even though the actual validated entry numbers are not winners, the entry ticket can be presented for a payout or sold by the owner to an unsuspecting party, causing various problems in the management of lottery entry tickets.

US Patents 4,488,808 - Kato and 3,199,450 - Leavens disclose apparatus to inspect printed forms to determine whether they have been properly printed and/or cut. In Kato, the forms are subdivided into areas and the reflectance of the form at the respective areas is compared to a standard to determine whether the tone of printing is dark enough. Although Kato can respond to tone variation, the apparatus is not useful for determining whether a printer having selectively operable elements such as segments or dots has failed in a limited way. In Leavens, a sensor is directed at a form cut from a web of successive forms having printed border lines, to determine whether the border lines are at the edge of the cut form as desired, again responding generally to the reflectance of the form in a defined area.

It is known to redundantly mark forms with corresponding data presented in two distinct forms. Lottery tickets are known, for example, with alphanumeric humanly-readable characters, and redundant machine readable codes and characters that are readable using automatic scanners. The scanners can discriminate bar code representations, marked areas in a field of potentially marked areas, optical character recognition (OCR) characters, etc. An example of a lottery ticket printer producing both alphanumeric and machine scannable indicia is disclosed for example in US Patent 4,695,171 - Sapitowicz. Scannable characters are helpful in allowing automatic entry of the serial number, validated entry numbers or other data when the form is presented to the lottery agent after purchase, for example to determine whether the ticket is a winner. The scanned codes were intended to represent the same alphanumeric characters which are optically discernable by human viewers. Scannable characters however do not preclude the possibility of error in the formation of the optically discernible

alphanumeric characters.

It would be advantageous to verify the correct formation of alphanumeric characters on a printed form so as to identify errors before a printed form is issued. However, optically discernible alphanumeric characters are not readily discriminated using inexpensive automatic scanners. Typically, automatically scannable code characters are less susceptible to defective printing than alphanumeric characters because the variations of light and dark are relatively more coarse or pronounced than alphanumeric characters, to facilitate quick automatic scanning. Nevertheless, defects in the scannable code characters can be detected.

According to the invention the same discrete printing elements are used to print humanly discernable characters and automatically scannable characters. A scanning mechanism directly associated with the printing mechanism reads the scannable characters and compares the results to a standard of quality. Insofar as the scannable characters are found to contain gaps or irregularities which characterize defective dots, segments or other mark forming elements, or defects due to irregular motion of the form or perhaps of a movable print head carriage, the printed form can be rejected prior to issue. Whereas the same printing elements form the scannable characters and the alphanumeric characters, defects in the alphanumeric characters are highly likely to be reflected by comparable defects in the scannable code characters. The invention provides a means to detect alphanumeric characters which appear as erroneous characters, and also provides an opportunity to determine whether the machine scannable data will in fact be dependably scannable when later presented.

Summary of the Invention

It is an object of the invention to employ an automated scanning mechanism for machine readable characters to verify the accuracy of alphanumeric characters intended to be read by humans.

It is another object of the invention to use the same printing means to form both alphanumeric and automatically scannable characters, whereby defects in one are reflected by the other, and to scan the automatically scannable characters as a means to verify the accuracy of the alphanumeric characters.

It a further object of the invention to form alphanumeric characters and bar code characters using the same printing means, the bar code characters being printed and scanned substantially contemporaneously with the printing of the form, and to assess the operability of the printing elements and feed mechanism by testing the ability to accurately scan the bar code, and in particular comparing the results of scanning the bar code characters to the characters which were attempted to be printed.

These and other objects are accomplished by a printer for forms such as lottery entry tickets, having a printing means which places both alphanumeric characters and machine scannable characters on a form, responsive to input data. The printing means and/or the form is moved relative to the other, from line to line and/or character position to character position, such that the point of printing advances laterally or longitudinally of the form, or both, so as to form successive characters. For example the printing means can be moved along a lateral print line by a carriage, and a form feed drive can advance the form to position a printing elements at successive lines. Alternatively, a fixed print head having a plurality of laterally spaced elements can form columns of characters as the form is advanced line by line. A scanner for reading the machine scannable characters previously printed by the printing means is mounted such that the scanner views characters formed by the individual print forming elements of the printer. The output data of the scanner is compared to data stored in memory representing the previously printed scannable characters. An error in the scanned code as

compared to the stored data is interpreted as a printer failure, and the form is rejected. The device is useful for assessing quality of the previously printed scannable characters as well as the alphanumeric characters because the characters are printed with the same printing elements and defective operation of one or more elements causes gaps in both forms of characters. The printing means can be a dot matrix device, a segment forming device, etc., and the scannable characters can represent bar coded representations of the alphanumeric characters. Alternatively, care can be taken that all the printing elements are exercised at least at one place on the form, which place is examined for the expected pattern. The scanner is either a fixed device with a scanning line-viewing device encompassing the area to be examined, or a movable viewing device which is passed over the area to be examined, for example carried along on a movable carriage with the print forming elements.

Brief Description of the Drawings

There are shown in the drawings the embodiments which are presently preferred. It should be understood that the invention is capable of embodiment in other specific forms in accordance with the invention as disclosed and claimed. In the drawings.

Fig. 1 is a partial perspective view of a form printer according to the invention;

Fig. 2 is a perspective illustration showing a form passing a movable print element carriage and scanning apparatus;

Fig. 3 is an exploded perspective view showing the detailed mechanical structure according to a preferred embodiment;

Fig. 4 is a block diagram showing the functional elements of the invention;

Fig. 5 is a plan view of a lottery ticket having alphanumeric and scannable indicia, illustrating a defect caused by an inoperable dot matrix element;

Fig. 6 is a schematic illustration of an alternative embodiment having fixed print elements operated in conjunction with a form feed mechanism, and a fixed scanner, the scanner encompassing the width of the print field; and,

Fig. 7 is a plan view of a form printed according to the embodiment of Fig. 6.

Detailed Description of the Preferred Embodiments A printer 90 as shown in Fig. 1 forms both alphanumeric characters and automatically scannable code characters on a form 10 in response to data at an input. The same printing elements 96 form both alphanumeric characters 52 and scannable code characters 54. In the event of operational defects in the printing apparatus such as the electrical failure of a driver or connection, or electrical or mechanical failure of a mark forming mechanism, the alphanumeric characters 52 and the automatically scannable code characters 54 both bear evidence of the failure, as shown for example by repeated gaps in the bar code characters in Fig. 5. Accordingly, by using an automatic scanning apparatus 60 to scan the form substantially contemporaneously with printing, it is possible according to the invention to check the intelligibility of the alphanumeric printing indirectly, and to determine directly whether the scannable characters will be dependably scannable later on.

Preferably, the automatic scanner 60 has a data output coupled to a processor 72 or similar device which compares the results of scanning to the data which was intended to be printed, i.e., the data transmitted to the printing mechanism for printing. An accept/reject signal or indication is then made with respect to the form 10.

The alphanumeric characters 52 can be letters or numbers in conventional arable form. Such characters are preferably formed by selective operation of discrete elements 94, for example mounted on a printing means or print head 96, to place marks which make up the character in timed or position coincidence with displacement of the printing elements 94 relative to the form 10. Of course either the form or the printing elements, or both, can be movable. It is possible to use a printing means having segments or bars which combine to define all the possible characters to be printed, or to use a dot matrix printing technique as illustrated, wherein a line or matrix of dot forming elements 94 are actuated to form characters in one pass or a plurality of passes laterally and/or longitudinally over the form 10. Dot matrix printers can, for

example, have 24 pins in an X-Y array, the pins being movable perpendicularly of the plane of the form via solenoids. Alternative printing elements can be based on non-impact print forming means, including ink jets, laser or electrostatic transfer elements, thermal elements and the like. Input data for characters to be printed is converted into dot position data or segment selection data with reference to a look-up table or font stored in memory in the controller. The elements are selectively activated while positioning the printing means using drive means such as stepping motors for moving the printing elements and/or form in steps.

The invention is applicable to other printing mechanisms having discrete elements which are selectively combined to form characters. For example, dot elements or segments can be selectively heated and applied to heat a spot on thermal paper, or ink jets can be selectively operated to impel a dot of ink directly onto the form. Fig. 6 illustrates an example of a thermal printer embodiment. The form advances via a form feed motor, but there is no movable carriage. Instead, separate character forming elements, such as seven segment heads, are positioned laterally across the form and operated selectively to define successive columns. The scanner for an apparatus of this type is preferably also fixed, but includes means such as a laser, collimating lens and rotating mirror, to provide a scan line which encompasses the area of printing to be examined as the form is advanced.

Referring to Fig. 5 and the embodiment of the invention according to Figs. 1-4, the scannable characters 54 printed on the form 10 can be bar code characters, i.e., a series of lines with a spacing and width that encodes data. Bar code is readily printed using selected operation of discrete elements or dot positions. Should, for example, one or more dot forming elements 94 of a dot matrix printing means 96 fail, when printing bar code the failure is readily apparent due to the contrast between lines parallel to the path of the printing elements where the failed element passes, and adjacent areas where the respective elements are operable. This aspect of the bar code is detectable using the scanner 60.

According to Figs. 1-4 the printing means 96 and the scanner 60 are carried on the same carriage 32, and are directed against the form 10 through openings 34, 36, for example through a ribbon shield panel of the carriage. The scanner is positioned so as to scan previously printed characters, either along the path of the carriage following the printing means (provided this is not occluded by a ribbon), or on an adjacent line of print which is scanned as the printing means passes along a subsequent line. In the embodiment according to Fig. 6 the scanner is directed at a full line subsequent to the current print line. Fig. 2 is a schematic representation of the passage of a movable print head/scanner carriage panel 32 over the form, and Fig. 3 is a schematic illustration of the operable parts.

The control and electronics elements of this printing apparatus are shown in Fig. 3. In order to compare the scanned data to previously printed data and thereby assess quality of the printing as well as the ability to scan the form, the device includes memory means 74, operable to store data received at the input to the printing apparatus and output to the printing means 96 for application to the form 10. A controller 72 is coupled to the memory 74, and to the input from the scanner 60, for comparing the printed data as detected by the automatic scanning apparatus to the data which was ostensibly printed.

The scanner 60 includes an LED light source and photodetector operable to illuminate an area of the form intersecting the scannable characters. Scanners of this type for distinguishing bar code are commonly provided in hand held scanning wands.

The controller 72, or other means for comparing the output of the automatic scanning apparatus to the data, can determine the ability of the scanning device to effectively scan and input data which should appear due to formation of the automatically scannable code characters 54. If the scanner is unable to input data from an area of the form which was expected to be scannable, for example due to a blank line being left across the print path due to failure of a printing element. The comparison also preferably checks quality by checking for one to one correspondence of the scanned

data to the stored data.

The automatically scannable code characters can be arranged to include at least one area 58 exercising all the dot or segment elements 94 of the printing mechanism. With formation of bar code lines, for example, all the dot positions in a matrix of potential dot positions can be marked to provide a test area, rather than only certain of the dot positions. In other words, the "characters" which are formed could include an area which is wholly darkened by darkening all possible points at least in one area of the form 10. The scanner can then examine the reflectance characteristics of this area, in particular whether it is evenly dark, as a means to determine whether all the printing elements are active.

The printing elements are operated in coincidence with relative movement of the form and the discrete dot or segment elements. As shown generally in Fig. 2 and more specifically in Fig. 3, the movable carriage mechanism 20 advances the printing means 96 along a carriage feed path 26 during printing. A drive motor 24 is coupled to the carriage 20 through a belt 22 and threaded shaft 42 such that rotation of the shaft moves the printing elements from side to side. Other forms of linear actuation are also possible, for example having the carriage 20 carried on a belt. The drive motor can be stepped incrementally in small counted steps by controller 72, the controller operating the pins in conjunction with printing element position as defined by the steps. Alternatively, the drive motor can be operated smoothly and continuously for advancing the carriage along the printing line, in which case the controller can read out dot or segment positions based upon timing. Preferably the feed is smooth or the steps are short and rapid, such that the scanner head 60 passes smoothly over the scannable characters 54.

For advancing the form 10 following completion of a printed line, form feed mechanism 88 can advance the form relative to the printing means 96 and scanner head 60 along a form feed path 80. The form feed mechanism includes a drive roller 84 coupled to a drive motor 82, and opposed by an idler roller 86 on the opposite

side of the form. The form feed mechanism can advance the form stepwise upon completion of a line, or it is also possible to use a continuous form feed with suitable skewing of the path of the printing elements. In the embodiment shown, the form feed path 80 and the carriage feed path 26 are substantially perpendicular.

Whereas the automatic scanning mechanism 60 is mounted on the carriage 20 and is advanced along the carriage feed path 26 together with the printing means 96, the automatic scanning mechanism scans the form 10 along a scanning line on or substantially parallel to the carriage feed path 26 and downstream of a current print position along at least one of the carriage feed path and the form feed path. In conjunction with bar code as the scannable characters, the spaced lines and bars of the bar code are elongated along the form feed path, for scanning along the carriage feed path. It would also be possible in a continuous form feed embodiment to apply the bar code so as to define lines and bars elongated in the carriage feed direction, and to scan them along the form feed path.

Normally the form feed advances the form 10 in increments equal to the line spacing for printing. In order to repetitively scan bar code or similar characters to detect gaps, it is also possible to advance the form by a smaller increment for scanning, such that the height of print along one pass of the printing means 96 is scanned more than once along a narrow scan line. Whereas the printing elements typically are disposed in an array having a height, repetitive scanning in this manner will detect the failure of a single element in the array.

With reference to Fig. 4, controller 72 is coupled to the printing means 96 for operation of the pins, ink jets, segments or other mark forming elements 94, for placing both alphanumeric characters 52 and at least one scannable character 54 on the form, at least partly in response to data at an input to the printing apparatus. The data output to the printing means for printing is stored by the controller 72 in memory 74. The controller is also coupled to the carriage drive for advancing the printing means along the form, and to the form drive for advancing the form

between lines. The scanning apparatus scans a previously printed scannable character, and by its output coupled to the controller allows the controller to compare the scanned data to data stored in memory 74. The result of this comparison is a measure of the quality of the previously printed scannable characters and, due to the fact that the same printing means 96 formed the alphanumeric characters as well, is also a measure of the quality of the alphanumeric printed characters. The controller provides an accept/reject indication with respect to the form based on the results of the comparison.

The scannable characters preferably redundantly represent at least some of the alphanumeric characters on the form, such that the scannable characters form an alternative means for input of data from the form at a later time. This technique is particularly applicable to printing of lottery tickets. Upon issuing the ticket to the player, the invention ensures that there are no errors in the printing mechanism that could cause the player to believe that the ticket was issued on a different set of play entry numbers than it actually was issued. Moreover, a similar form of scanner is used by ticket readers which encode the ticket data when the ticket is later presented by the player to the lottery agent, for example to check for the win status of the ticket, to claim a prize, or perhaps to replay the same numbers at a later date. The scanner according to the invention checks preliminarily whether the scannable characters can be read, thereby preventing issue of an unscannable ticket. As shown in Fig. 5, the form 10 can be printed with alphanumeric characters 52, bar code 54, segment characters 56 and/or position-marking darkened areas 58. The form can also have pre-printed indicia, to which one or more of the foregoing characters are added by the printer.

Fig. 3 illustrates a preferred embodiment of the invention in detail. The respective parts are mounted on a chassis 46, having a form drive section 88 at the front, carrying form drive roller 84, which is coupled to drive motor 82 by a belt 44. The carriage drive motor 24 is mounted opposite the form drive motor 82, and is coupled to threaded shaft 42 by a belt 22. Carriage 20 is has a

threaded cylinder or nut 30 which is carried on shaft 42, and the rear of the carriage can slide along rail 28, for positioning the printing means 96 having discrete elements 94 and scanner head 60 relative to the form.

In the alternative embodiment shown in Fig. 6 the form is advanced under a plurality of print elements which are fixed in position, spaced laterally of the feed path 70 on a substrate 51. The print elements, for example, can be seven segment elements having separately controllable segments 50 which are enabled in combinations which define characters 56, shown in Fig. 7. This arrangement is typical of a thermal printer wherein the segments 50 are resistors which are heated to darken selected areas of a thermal paper. Other forms of segment or dot printers are also applicable. As form 10 is advanced along the feed path 70, typically in steps, the segments are activated.

Downstream of the print elements along feed path 70, a fixed scanner having means for viewing the form across the width of the print area encompassed by the overall print head is arranged to scan an area 79 corresponding to the areas of printed characters. The scanner can include, for example, a laser 66 incident on a mirror 76 rotated by a motor 77 to scan beam 67 across the form 10 in the viewing area 79. A collimating lens 78 can convert the radially scanning beam produced by the mirror 76 into a linearly scanning beam across area 79. Light reflected from the form and detected, corresponds to the light and dark reflectance variations produced on the thermal paper of the form by segments 50.

A form 10 printed according to the embodiment of Fig. 6 is shown in Fig. 7. The human readable seven segment formed characters 56, are to be redundantly represented by machine readable characters 59. In the example shown the machine readable characters are placed in positions along the feed direction corresponding to their value, with "one" being the highest position and "nine" the lowest position in the feed direction. However, it will be noted that in scanning the code the scanner can readily determine that the scannable character corresponding to the number "five" is actually located in this example at the number "six"

position in the scannable code. Therefore, the number five in the human-readable characters 56, although it appears perfectly formed, is erroneous. The segment element 57, shown in Figs. 6 and 7, is inoperative and the form is defective.

As also shown in Fig. 7, the quality of the printed characters can be examined by providing a pattern 64 wherein the controller for the printer exercises all the segments, dots or the like. This form of pattern can also be compared to the standard pattern by a scanner located downstream of the printing means along the print path and likewise shows that segment 57 is bad. The pattern 64 as shown does not place the segments in the same relative positions as when printing alphanumeric characters, however this is also a possibility (i.e., a line of "eights"). The pattern 64 which exercises all the segments can be placed wherever convenient, and even distributed around the entire area of the form. Although pattern 64 provides a means for identifying an error, it does not redundantly encode the numbers which were intended to be printed. Therefore, a form 10 bearing only human-readable characters 56 and segment exercising characters 64, although possible, is not preferred.

The invention having been disclosed, variations on the inventive concept will now become apparent to persons skilled in the art. Reference should be made to the appended claims rather than the foregoing disclosure of exemplary embodiments, to determine the scope of the invention in which exclusive rights are claimed.