Patent Grant
8576264
The invention disclosed herein relates generally to mail processing systems, and more particularly to a registration device for mail processing systems that utilize wide print nozzle arrays.
Mail processing systems, such as, for example, a mailing machine, inserter, and the like, often include different modules that automate the processes of producing mail pieces. A typical mail processing system includes a variety of different modules or sub-systems each of which performs a different task on the mail piece. The mail piece is conveyed downstream utilizing a transport mechanism, such as rollers or a belt, to each of the modules. In a mailing machine, such modules could include, for example, a singulating module, i.e., separating a stack of mail pieces such that the mail pieces are conveyed one at a time along the transport path, a moistening/sealing module, i.e., wetting and closing the glued flap of an envelope, a weighing module, and a metering/printing module, i.e., applying evidence of postage to the mail piece. In an inserter, such modules could include one or more feeders and collators, an envelope stuffing module, a moistening/sealing module, i.e., wetting and closing the glued flap of an envelope, a weighing module, and a metering/printing module, i.e., applying evidence of postage to the mail piece. The exact configuration of the mail processing system is, of course, particular to the needs of the user.
Modern mail processing systems utilize digital printing techniques for producing images on a mail piece. Conventional digital printing techniques include bubble jet and ink jet, each of which produces an image in a dot matrix pattern. With digital printing, individual print head elements (such as resistors or piezoelectric elements) are selectively electronically stimulated to expel drops of ink from a reservoir onto a substrate, e.g., a mail piece. In either case, by controlling the timing of energizing of the individual print head elements in conjunction with the relative movement between the print head and the mail piece, a dot matrix pattern is produced in the visual form of the desired image. In the case of mail processing systems, the image may be, for example, an indicium that evidences payment of postage or advertisements printed on the outside of a mail piece.
Digital printing technology has significant advantages when used in a mail handling apparatus as compared to older technology that utilized either a flat platen or a rotary drum to imprint information, such as, for example, address information or an indicium, on mail pieces. For example, if some variable image data needs to be changed, it can easily be done through the installation of new or upgraded software versus having to replace the entire printing module, since the flat platen and drum are typically not separately removable. Moreover, greater printing speeds can be obtained as compared to conventional mechanical printing systems. However, the use of a digital print head in a mailing system presents other issues that must be taken into consideration. For example, for the ink jet nozzles of an ink jet printer to properly deposit ink on the surface of the receiving medium, it is critical that a small predetermined gap be maintained between the exit plane of the nozzles and the surface of the receiving medium, typically in the order of 0.02 to 0.08 inches (0.5 to 2.0 mm). This gap is necessary to achieve acceptable image quality, since too small a gap causes scuffing of the print head and to large a gap results in inaccurate dot placement, with either situation resulting in a deteriorated print image. Thus, in the mail handling environment, it becomes necessary to maintain this critical gap between the exit plane of the ink jet nozzles and the upper surface of the mail pieces being conveyed through the mailing machine.
To accomplish this, the mail pieces, such as, for example, envelopes, postcards, flats, and the like, must be conveyed with the front panels on which the information is printed lying in a fixed registration plane, which is disposed beneath the exit plane of the nozzles a distance equal to the aforementioned gap. This arrangement is referred to hereinafter as top registration. To accomplish this top registration, a biasing force is applied to the back panel of the mail piece such that the front panel maintains light contact with a registration plate. This contact slightly compresses and flattens out the mail piece, thereby establishing its surface at the ideal gap distance from the print head nozzles. An opening is provided in the registration plate, above which the print head is located such that the print head can print on the mail piece as it passes the opening in the registration plate.
There are problems, however, with the conventional top registration transports in mail processing systems. Conventional registration plates maintain the desired gap when printing on thin or constant thickness media in which the print surface is flat. When printing on variable thickness media, however, such as mail pieces that are filled with different amount of inserts that tend to make the mail pieces “puffy” or have distorted top surfaces, it is difficult for conventional registration plates to maintain the desired gap due to the variations in the surface profile of the mail piece. This problem is exacerbated when the printing zones are wide, which requires the use of wide print nozzle arrays to perform the printing, as the openings in the registration plate must also be larger to accommodate the print nozzle arrays. These larger openings do not provide support for the mail pieces, resulting in large variations in the surface profile of many mail pieces as they pass under the print nozzles. This results in variations in the spacing between the print nozzles and the surface of the mail piece, which in turn causes poor print quality. In addition, the variations in the surface profile can result in a portion of the mail piece surface protruding into the opening and contacting the print nozzles as it is transported past the print head, which can cause smearing of the ink and potentially damage the print nozzles. Additionally, if there is a jam of the mail pieces being transported in the printing area, there is a much greater chance that a mail piece will be forced into the opening, because of the larger openings, and contact the print nozzles.
Thus, there exists a need for a top registration device for a mail processing system that utilizes wide print nozzle arrays that reduces the problems associated with printing on variable thickness media.
The present invention alleviates the problems associated with the prior art and provides a registration device for a mail processing system having wide print nozzle arrays that reduces the problems associated with printing on variable thickness media.
In accordance with an embodiment of the present invention, a thin wire, held by guides, is strung across the print nozzle openings in the registration plate to support and guide the top (print) surface of a mail piece and to prevent the mail piece from protruding into the openings. The guides are positioned such that the wire passes between zones where there are no nozzles located, thereby avoiding obstruction of the ink droplets as they are expelled from the nozzles onto a mail piece. A tensioning device is provided to adjust the tension of the wire to ensure the wire maintains its position within the openings. The wire is sufficiently thin such that any ink build up on the wires from the ink jet overspray is minimized, thereby minimizing any subsequent transfer of ink to a mail piece when contact with the wire occurs. The wire acts as a guide to maintain the optimal gap between the mail piece top surface and the print nozzles, thereby providing better print quality, and also to prevent the mail pieces from contacting the print nozzles during normal operation and in the event of a jam condition.
Therefore, it should now be apparent that the invention substantially achieves all the above aspects and advantages. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The accompanying drawings illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description given below, by way of example serve to explain the invention in more detail. As shown throughout the drawings, like reference numerals designate like or corresponding parts.
In describing the present invention, reference is made to the drawings, wherein there is seen in
To reduce ink smearing, especially on thick mail pieces, it is desirable to prevent the top surface of the mail piece from directly contacting the underside of the registration plate 40 downstream of any print head nozzle arrays 44. To achieve this, those areas of the registration plate 40 are preferably recessed and small idler rollers 50 are mounted on the bottom of the registration plate 40. The idler rollers 50 are mounted such that their outer radius re-establishes the upward planar bound of the mail piece just slightly below the bottom surface of the registration plate 40, thereby preventing the mail piece from contacting the bottom surface of the registration plate 40 in the areas where the idler rollers 50 are located. The idler rollers 50 preferably have small sharp points on their radial perimeter thereby minimizing the point contact with the mail piece, thereby reducing the transfer or smearing of any ink on the mail piece.
Because of the necessary openings 42a-42d required in the registration plate 40, there is no top support for the mail pieces as they pass under these openings, as the idler rollers 50 cannot be mounted in the openings 42. The size of these openings 42a-42d is dictated by the size of the print head nozzle arrays 44, and therefore must be wide enough and long enough to accommodate the entire print head nozzle arrays 44. The size of the necessary openings 42a-42d results in a high probability that very puffy or highly distorted mail pieces, having a free thickness that is greater than the gap established between the registration plate 40 and the transport 16, will protrude up into an opening 42a-42d. If this protrusion is greater than the nominal print spacing, the mail piece can extend above the plane established by the underside of the registration plate 40 and can contact the print head nozzle arrays 44. Such contact can cause smearing of the ink, or in worst case situations even damage the print head nozzle arrays 44, resulting in poor print quality.
To prevent such contact between the mail piece and print head nozzle arrays 44 from occurring, the openings 42a-42d in the registration plate 40 are provided with a barrier in the form of a very thin wire 52 that is strung across the openings 42a-42d. The wire 52 is preferably formed of a material that is resistive to corrosion, such as, for example, stainless steel, and has a diameter in the range of 0.010 inch. The wire 52 can be attached to the registration plate 40 by an attachment means, such as, for example, by crimping a ring terminal 54 onto the end of the wire 52 and securing the ring terminal 54 in a recess in the registration plate 40. The wire 52 is routed to a guide 56a located at a corner of a respective opening 42. The wire is strung across an opening 42a, routed by additional wire guides 56b, 56c, 56d . . . 56g located on the edges of the opening 42a. As can be seen in
The end of the wire 52 is preferably attached to a tensioning device 60 that allows the tension of the wire 52 to be adjusted (either manually or automatically) to remove any slack in the wire 52. An example of such a tensioning device is illustrated in
By having the guides 56 mounted either flush with the bottom surface of the registration plate 40 or within a respective recess in the registration plate 40, the wire 52 is preferably located between the planes established by the edges of the idler rollers 50 and the surface of the print head nozzle arrays 42, thereby reducing the amount of direct contact between the mail piece surface and the wire 52. Additionally, the relative thinness of the wire 52 minimizes the build-up of ink on the wire 52 due to the ink jet aerosol overspray. Such build-up is undesirable, as it may lead to subsequent transfer of the ink to the mail piece when a mail piece does contact the wire 52.
When a mail piece that is very puffy or highly distorted is being processed by the mail processing system 10, the wire 52 extending across the opening 42 will prevent the mail piece from protruding up into the openings 42, thereby preventing the mail piece from contacting the print head nozzle arrays 44. By preventing such protrusion in to the opening 42, any ink smearing or damage to the print head nozzle arrays 44 can be prevented. By providing the wire 52 to act as a guide to maintain the optimal gap between the mail piece top surface and the print nozzles, better print quality can be provided, as well as preventing damage to the print head nozzle arrays 44 caused the mail piece contacting the print nozzles.
It should be understood that while the above description was with respect to a mailing system 10, the present invention is not so limited and can be utilized with any type of printing system.
While preferred embodiments of the invention have been described and illustrated above, it should be understood that they are exemplary of the invention and are not to be considered as limiting. Additions, deletions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as limited by the foregoing description but is only limited by the scope of the appended claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5923343 | Brosseau et al. | Jul 1999 | A |
| Number | Date | Country | |
|---|---|---|---|
| 20130127968 A1 | May 2013 | US |
