Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
1999-04-21
2001-06-26
Hilten, John S. (Department: 2854)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C400S605000
Reexamination Certificate
active
06250754
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a printer comprising a frame, at least one first receptacle for the sheets to be printed, a sheet feeding path with a printing zone and at least one second receptacle for receiving the printed sheets.
BACKGROUND OF THE INVENTION
Duplex printing within the framework of printers using an ink that needs a certain length of time to dry, such as ink jet printers, is delicate on account of the fact that the ink of a sheet printed on its front face can easily come into contact with members of the printer, such as the guiding walls, during the reversal of the sheet, giving rise to undesirable ink erasures and blotches.
A large size printer is known from U.S. Pat. No. 4,918,490 in which the sheets slide, between the printing of the first and of the second face, in a long guiding channel the length of which is approximately three sheets. In this channel, the printed face touches the walls of the channel. For this reason, the arrangement described in this American patent cannot be used as part of ink printers having a more or less lengthy drying time, such as ink jet printers. Moreover, the printer described in this American patent is complex to build and has large overall dimensions, making it impossible to use for many applications.
SUMMARY OF THE INVENTION
The object of this invention is to overcome the drawbacks cited above and to create a printer permitting reliable duplex printing, including with inks having a relatively long drying time, such as ink jet printers. This printer shall in addition have to be easy to build and low reduced overall dimensions, while ensuring high quality printing. The cost price of the printer, moreover, shall have to be as low as possible.
The printer according to the invention is accordingly characterized by the fact that it comprises an installation for the duplex printing of sheets with an intermediate storing device having at least one storage tray, this installation being equipped with a control mechanism suitable for displacing the intermediate storing device so that the sheet or sheets printed on a first face can, successive to a printing exit, be fed into the storage tray or trays, in which a sheet is retained with its printed face facing upwards and from which the sheet or sheets may be fed again, for the printing of their second face, through a printing entrance into the feeding path, the latter being arranged in such a way that the sheet or sheets effect a reversal between the printing entrance and exit.
Accordingly, the ink still wet from printing can dry during a predetermined period of time when the sheet is kept in the intermediate storage tray. This storage tray is also used as a conveying means for presenting the sheet at the printing entrance again so that printing can be effected on its second face. This disposition therefore permits, reliably and simply, the effecting of duplex printing within the framework of ink jet printers or other types of printers with drying inks. The invention also permits a reduction of the overall dimensions of duplex printers and it is simple to build, using a small number of parts, at a reasonable cost price. The quality and speed of handling of the sheets are also very high.
To advantage, each storage tray comprises substantially at its entrance a conveying device provided for gripping and feeding a printed sheet into the storage tray, for keeping it during the intermediate storage and for feeding it again through the printing entrance into the said feeding path for the printing of its second face.
These characteristics ensure an optimal intermediate storage and drying, while facilitating the handling of the sheets.
According to a preferred embodiment, the second receptacle and the storage tray or trays together form an integral whole, mounted movably on the frame.
A particularly simple construction and very low overall dimensions are accordingly obtained.
Advantageously, the second receptacle is provided, substantially at its entrance, with a number of superposed conveying members identical in number to that of the superposed storage trays, the conveying members of the storage trays and those of the second receptacle being arranged identically, one on top of the other, so that the corresponding conveying members of one of the storage trays and of the second receptacle are suitable for meshing simultaneously with two driving members superposed on the frame and separated from each other by a predetermined distance.
The driving of the sheet conveying members is accordingly performed in a particularly rational and reliable manner and with very few components.
REFERENCES:
patent: 4453841 (1984-06-01), Bobick et al.
patent: 4918490 (1990-04-01), Stemmle
patent: 5820282 (1998-10-01), Nakai
patent: 5991564 (1999-11-01), Ni
Banner & Witcoff, LT
Cone Darius N.
Hilten John S.
Olivetti Lexikon S.p.A.
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