Incremental printing of symbolic information – Ink jet – Combined
Reexamination Certificate
1999-05-20
2001-10-02
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Combined
Reexamination Certificate
active
06296339
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a device for printing to stock, in particular a piece of mail in postage meters and/or addressing machines.
With such devices, the stock is guided past a printing device and the postage indicia or address is printed in a single pass.
The stock is typically guided past the printing device while lying flat as is seen in U.S. Pat. No. 5,467,709, for example, or on edge as is seen in U.S. Pat. No. 5,025,386, for example.
In each case, it is important to ensure that the stock and the printing device are brought into a defined position relative to one another so that the mark is printed in the intended location and with sufficient quality.
In the case of horizontal transport of the stock, a relatively large bearing surface, corresponding to the largest stock format to be printed, is required, thus the machine has a correspondingly large footprint.
In the device disclosed in U.S. Pat. No. 5,467,709, an ink jet print head provides contactless printing. The piece of mail is fed between a driven conveyor and spring-mounted pressure rollers, whereby the piece of mail rests against a longitudinal guide plate. The longitudinal guide plate has a cutout matching the conveyor and a rectangular cutout for the ink jet print head. A row of nozzles in the print head run along the diagonal of the cutout. The conveyor, the longitudinal guide plate and the ink jet print head are located above the piece of mail. Spring-mounted pressure rollers and a spring-mounted pressure roller located in the print area are located below the piece of mail.
The spring travel of the pressure rollers and the pressure plate corresponds to the maximum thickness of the piece of mail, which can vary between 2 mm and 20 mm.
The spring force must be appropriate for the entire range of weights of pieces of mail, approximately 20 to 1000 g, and must also ensure that the piece of mail is held sufficiently planar in the area of the cutout for the print head.
Contactless ink jet printing requires that the smallest possible distance be maintained between the stock and the ink jet print head. That both minimizes the effects of inaccurate ink spray and prevents the stock from contacting the nozzle surface, thus preventing smearing.
However, there is still a risk of smearing when the piece of mail leaves the area of the cutout and inevitably glides along the longitudinal guide plate.
These conditions are difficult to maintain when rapidly processing pieces of mail of varying dimensions. In other words, the rapid processing does not allow the ink to dry prior to further transport following the imprint.
The prior art also discloses a postage meter, as is seen in U.S. Pat. No. 5,025,386, in which the piece of mail is carried on edge and slightly inclined on a rotating conveyor. The pieces of mail rest against a guide block which has a print window. A thermal print head with which the postage indicia is printed on the piece of mail can be moved laterally and vertically within the print window.
The size of the print window must be adapted to the maximum length and width of the printed image.
The individual piece of mail is transported to the print window, then stopped and pressed through the use of a pressure plate against the guide plate or the print window. The pressure plate is driven by a motor through a toothed gearing and crankshaft. It is a relatively complex mechanism and significant counterpressure must also be provided for thermal printing.
After printing, the piece of mail is released and transported away. It is clear that only a low throughput is possible with such an intermittent mode of operation. Positioning of the thermal print head is complex.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a device for printing stock in non-vertical orientation, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which provides simplified transport of a piece of mail and improved printing technology. It is furthermore an object of the present invention to create a device for transporting stock which ensures precise feeding of the stock and a clean printed image through the use of a simple construction.
With the foregoing and other objects in view there is provided, in accordance with the invention, a device for printing to non-vertical stock, in particular a piece of mail in a postage meter or addressing machine, comprising:
a non-vertically aligned guide plate having one side along which stock slides in non-vertical orientation in a transport direction during transport and printing, a downstream end, a recessed region having at least one cutout, and a region following the at least one cutout toward the downstream end at which the stock is substantially free of contact with the guide plate;
an advancing device for advancing the stock along the guide plate in the transport direction; and
an ink jet print head of an ink jet printing device for printing to the stock disposed in the recessed region, the ink jet print head having a nozzle plane oriented substantially parallel to the guide plate.
Since printing is contactless, the required pressures are low and friction on the guide plate can be minimized through the use of a correspondingly smooth surface and sliding rails.
In accordance with another feature of the invention, the configuration of the region of the guide plate downstream of the print area or the cutout ensures that the stock is not supported at this location. This ensures a sufficiently long penetration time for the ink, preventing smearing of the printed image.
In accordance with a further feature of the invention, the fact that the nozzle plane is recessed relative to the region upstream of the cutout and that the downstream region is even farther recessed or open prevents the stock from catching on one of the edges.
Specifically, the region of the guide plate downstream of the cutout is either itself cut away or recessed relative to the bearing surface for the stock by an amount which is greater than the greatest expected convexity of the stock in the printed area. This clearance is achieved either by mechanical shaping, such as through the use of the mold in the case of plastic injection molding, or through the use of some metal removing process.
In the latter two variants, this amounts to only a few tenths of a millimeter, but can be as much as two millimeters to achieve the desired graduated recess.
In accordance with an added feature of the invention, the installation of sliding rails running in the direction of transport on the guide plate greatly reduces the bearing surface for the pieces of mail and thus the friction. The aforementioned unsupported area for the printed area of the stock is easily realized in that the sliding rails are farther apart than the printed image is wide and thicker than the greatest expected convexity of the stock.
In accordance with an additional feature of the invention, there is provided an insert of stainless steel as the structured portion of the guide plate, which provides several advantages. This insert can be stamped or cut to size from a piece of sheet metal. Stainless steel can be highly polished, it resists abrasion and it has good sliding properties. The metal effectively dissipates static electricity.
In accordance with yet another feature of the invention, if the postage indicia and address are to be printed in a single pass, an ink jet print head can still be used but an appropriate positioning mechanism for the print head is then required.
If there is a separate ink jet print head for each cutout or print function, not only is there no need for a positioning mechanism, but different colored inks can also be used, such as red for the postage indicia and black for the address.
In accordance with again a further feature of the invention, mounting the incremental transducer and the drive roller on a common axis and the use of a synchronous belt as the conveyor ensures precise monitoring of the conveying distanc
Geserich Frank
Inten Wolfgang Von
Barlow John
Francotyp-Postalia AG & Co.
Greenberg Laurence A.
Huffman Julian D.
Lerner Herbert L.
LandOfFree
Device for printing to stock in non-vertical orientation does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for printing to stock in non-vertical orientation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for printing to stock in non-vertical orientation will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2578219