Printer With Inker on the Platen Roller

The invention relates to apparatus for printing information on an information carrier which lies against a platen. The apparatus comprises a rotary stamp for printing on the information carrier as it moves between the platen and the stamp. The stamp receives its ink from an inking device, information is printed on the carrier by a rolling movement of the stamp on the carrier. The platen is formed with at least one groove having two edges and a bottom. The groove is situated between planes which bound at least one annular stamp surface carrying the printing faces, a part of the stamp periphery carrying the printing faces on the annular surface extends into the groove without touching the edges at least in the absence of an information carrier, and there are provided reset means which act between the spindle of the stamp and that of the platen to move the stamp and the groove towards each other.

The invention is concerned with office automation, in particular information processing, for example automated document processing, specifically of commercial documents such as cheques, bills for exchange, order forms, bills to be protested, etc.

Equipment intended for this purpose, such as check readers or stamping machines, become more and more sophisticated and compact.

For example, when processing a check it is frequently necessary to write information on the face of the check at a specific location. When a rotary ink stamp is used for this purpose it is necessary to synchronize the movement of the check and the rotation of the stamp which is applied to the check which is backed by a rotary platen, in particular a rotating drum. Moreover, after the desired information has been printed on the check care must be taken that during the next revolution the stamp does not print the same information at another undersired location on the check or on the drum itself after the passage of the check, so that the next check would be stained.

It is the object of the invention to provide a cheaper solution, using a more compact construction, to a technical problem similar to that described in the foregoing paragraph in order to achieve stamping of information carriers with less restrains than indicated in the foregoing. In specific cases, in particular when a stamp is to be applied to the back of the check (the face of the check then being applied to the drum), information may be printed over the entire length of the check without the necessity of synchronizing the movement of the check and the rotation of the stamp. The information need not be printed at a precise location on the check and the printed information may be repeated after each revolution of the stamp. Moreover, this does not solve the problem of precluding that ink is applied to the drum after the passage of the check and the next check is stained by the drum itself. In order to solve the last-mentioned problem it is known from U.S. Pat. No. 3,090,302 to form the platen with a groove having two edges and a bottom, such that, at least in the absence of an information carrier, a part of the periphery of the stamp extends into the groove without touching the edges. However, such an apparatus remains rather bulky and expensive because it employs an inking device, which is separated from the stamp and the platen.

According to the invention, the last-mentioned drawbacks are precluded by an information-printing apparatus as defined in the opening paragraph, which is characterized in that the bottom of the groove carries the inking device, said reset means urging the stamp and the bottom of the groove towards each other in the absence of an information carrier.

When the leading edge of the check, as it is advanced, reaches the stamp, the part of said edge which covers the groove comes into contact with the stamp and lifts it slightly, during which the surface of the check may be curved slightly at the location where the stamp rests against the check, i.e. at the area to be printed, after which the stamp is rotated, which may be caused by the friction exerted on the check by the periphery of the stamp. Before the stamp and the check contact each other the stamp generally rotates already, which is desirable in order to ensure a correct linking of the printing faces and also in order to preclude shifting during the transient condition when the stamp comes into contact with the check.

One embodiment of the invention is characterized in that the inking device comprises an ink pad arranged on the bottom of said groove.

In an embodiment which is compatible with the last-mentioned embodiment the platen comprises two parts which are secured to each other at the location of the groove, the ink pad, which takes the form of a ring, being slid onto the bottom of the groove before the parts of the platen are secured to each other.

Embodiments of the invention will now be described in more detail, by way of example, with reference to the drawings.

FIGS. 1a and 1b illustrate the prior art, partly in a sectional view.

FIGS. 2a and 2b are an elevation and a plan view, respectively, of a version of the reset means which act for example on the spindle of the stamp.

FIG. 3 is an elevation of a version of the stamp.

FIG. 4 is a plan view, partly broken away, of drive means for the stamp.

FIG. 5 shows an embodiment of the invention partly in sectional view and partly broken away.

FIG. 6, partly in sectional view and partly broken away, shows a possible version of the rotary platen, intended for simultaneously printing a plurality of text lines.

FIGS. 1a and 1b are sectional views of an information-printing apparatus, which comprises a platen 1 which is rotatable about an axis 2, and of which only the lefthand part is shown, and a stamp 3 comprising a circular disk. The stamp 3 has a spindle 4 which is mounted for rotation by means of an arm 5 whose other end is pivotable about a spindle 6. The stamp 3 is inked by known means, not shown. The spindles 2 and 6 are supported by a base plate, not shown, which extends parallel to the plane of drawing. The platen 1, which is rotated by known means, preferably by a belt (not shown) arranged over a part of its periphery, serves mainly for transferring an information-carrying document, for example a commercial document, such as 7 in FIG. 1b, while allowing information to be printed on it by known methods, in particular by means of the ink stamp 3. The platen 1 may comprise the main document-transport drum or a simple roller disposed along the document path. In particular if the space available around the main drum is small and/or if printing on the back of the document is required when the main drum is in contact with the other side, the platen 1 preferably comprises a document guide roller arranged in the immediate proximity of the main drum. The platen 1 is formed with a groove 8 of, for example, rectangular cross-section at the location of the circular surface of the stamp 3, into which groove the periphery of the stamp carrying the printing faces extends freely without touching the edges. The stamp 3 is urged towards the groove 8 by a spring 9 which exerts a return force on the arm 5 in the direction indicated by the arrow 11 (see FIG. 1a). As the platen rotates in the direction indicated by the arrow 12, when the information carrier, which is moved, for example, by the platen 1 to which it is applied reaches the stamp 3, its leading edge 10, at the location of the groove 8, meets that part 14 of the stamp 3 which is disposed inside the groove (FIG. 1a), as a result of which the stamp is lifted against the force of the spring 9 in the direction indicated by the arrow 13 and during all the time that the document 7 travels to the right of the stamp 3, the stamp 3 rolls on the document without sliding, so that said document is printed over its entire length. During printing the document is generally curved slightly at the point of contact between the document and the stamp and at this location the document slightly penetrates into the groove. In order to preclude too deep a penetration of the document, which would result in incorrect printing, the edge-to-edge dimension of the groove is hardly greater than the thickness of the stamp, which is centered relative to the grooves so that it cannot come into contact with the edges in the absence of a document. This technical feature is apparent in particular from FIG. 2a. Since too deep a penetration may lead to the characters being printed irregularly and in particular very faintly in the center, a comparatively simple means to overcome this problem is to use characters whose profile is curved in the vertical direction, as indicated by 30 in FIG. 3. For example, flat flexible characters may be glued on a curved support (periphery of the stamp). It is to be noted that the groove may be of semi-circular or other cross-section, provided that it has two edges and a bottom.

In FIGS. 2a and 2b, which show an information-printing apparatus in elevation and in plan view respectively, the principal element of FIGS. 1a and 1b are designated by the same reference numerals. The groove 8 formed in the platen 1 has two edges 16 and a bottom 17. The documents may be clamped between, for example, a driven or driving belt 18, and the platen 1. The spindle 2 of the platen 1 is journalled on a base plate 19 which also carries a rigidly mounted post 20. One of the ends of a plate or leaf spring 21 is secured to the post 20, its other end, which is recessed to allow the passage of the stamp 3, comprises two limbs 22 in which the spindle 4 of the stamp 3 is journalled. In the absence of a document a small portion of the periphery of the stamp 3 extends into the groove so that it touches or does not touch the bottom 17 of this groove. For example, in FIG. 2b the stamp 3 is shown to be in contact with the bottom of the groove 8. During the passage of a document, the operation of the apparatus is as described in the foregoing with reference to FIGS. 1a and 1b; after the passage and simultaneous printing of a document, the groove 8 ensures that no part of the platen can come into contact with the next document so that this next document is not and cannot be stained. The apparatus in accordance with the invention serves for printing a text on documents at a specific height but not at a specific location in the longitudinal direction of the document. The only limitation imposed is that the text to be printed will appear at least one time completely on each document. Since there is no synchronization between the document movement and the movement of the stamp, it is necessary to ensure that the circumference of the stamp is at least equal to half the length of the document.

In FIGS. 3 to 6 elements with the same functions as those in FIGS. 1a, 1b, 2a,2b bear the same reference numerals and in order to simplify the drawing the base plate 19, the right-hand part of the platen 1 and the reset means which act on the stamp spindle are not shown, which elements may be similar to the elements designated 5, 6 and 9 in FIGS. 1a and 1b or 20, 21 and 22 in FIGS. 2a and 2b. Alternatively, the reset means may act on the spindle of the platen, the spindle of the stamp then being stationary relative to the base plate.

FIG. 4 is a plan view of means which may be used for driving the stamp 3. A pulley 27, which is rigidly connected to the spindle 4, is rotated by a belt 28, for example a round belt. The belt 28 is driven by a pulley 29 whose spindle 31 is supported by the base plate. The pulley 29 and the platen 1 are coupled to each other so that their degrees of rotation are proportional to each other. The respective diameters of the pulleys 27 and 29 are such that during operation the tangential speeds at the periphery of the stamp 3 and at the periphery of the platen 1 are equal. The stamp 3 is inked, for example as indicated in FIG. 3, by means of a separate rotating pad 25, the ink supply being permanent, i.e. inking is effected both during printing and in the absence of a document. The spindle of the ink pad is then mounted for rotation on the arm 5 (FIG. 1) or on a part which is rigidly connected to the leaf spring 21 (FIG. 2). Basically, the apparatus operates as described with reference to FIGS. 1a, 1b, 2a and 2b.

FIG. 5 shows an embodiment of the invention which enables the apparatus to be simplified even further: the inking device is arranged on the bottom of the groove. In practice, an ink pad comprising an ink ribbon 32, for example of a porous material impregnated with ink or of the ink-film type, is glued to the bottom of the groove, its width being substantially equal to the width of the groove and its thickness being smaller than the depth of the groove. If there is no document the reset means urge the stamp and the ribbon 32 towards each other to ensure a correct inking. The remainder of the operation of the apparatus is the same as described in the foregoing, except that during the passage of the document and during printing the stamp which carries the printing faces no longer receives ink. It follows that the line printed on the document is more distinct at the end than at the beginning. However, this effect is minimal and the information to be printed remains perfectly legible. By way of variant the ink ribbon 32, whose elasticity is low, may take the form of a ring. The platen then comprises two parts which are secured to each other at the location of the groove. When this variant, which is shown in FIG. 6, is used it is alternatively possible to simply form a plurality of superimposed grooves for printing a plurality of text lines by means of an ink pad comprising a plurality of circular surfaces. In FIG. 6 the platen is shown to comprise two separate parts: upper part 34 comprising the upper edge and, for example, the bottom of the groove 8 and a lower part 35 which comprises the lower edge of the groove 8. However, conversely the lower part 35 may comprise the bottom of the groove 8. The stamp 3 comprises, for example, two circular discs, the upper disc 36 and the lower disc 37. The platen which has two grooves with inking rings on the bottoms of the grooves is assembled as follows: when the two parts 34 and 35 are still separated a first inking ring 38 is placed on the bottom of the groove and pushed upwards until it is located near the upper edge of the groove, subsequently a metal washer 39 is fitted until it touches the ring 38, the inner diameter of this washer being equal to the diameter at the bottom of the groove and its outer diameter being equal to that of the platen. This operation is repeated for the inking ring 40. Since sliding means are present between the parts 34 and 35, the part 35 is slid into the part 34 until the inking ring 38 is situated near the lower edge of the groove. The parts 34 and 35 may be connected to each other by any known means, not shown, for example, be screwing one part to the other or by sliding one part into the other, after which they are secured by a bayonet coupling or by means of screws provided for this purpose.

The invention is not limited to the examples described in the foregoing. During its passage between the stamp and the platen the information carrier does not necessarily revolve around the platen. On the other hand, for the embodiments described in the foregoing with reference to FIGS. 3, 5 and 6 the movement impressed on the assembly of elements such as the platen, the stamp, the information carrier and as the case may be the inking pad, can be obtained by driving any of these elements or by driving a combination of two of these elements, because these elements engage frictionally with each other without slipping. The platen need neither be circular nor rotatable by may, for example, be flat, and it may be driven with a translational movement for printing information on the information carrier. In the last-mentioned case the groove has for example the shape of a rectangular parallelepiped. Moreover, the invention is not limited to check readers or to stamping machines and may be employed in, for example, printing machines in general or in labelling machines.