Electrophotography – Document handling – Copy
Reexamination Certificate
2001-07-24
2003-07-22
Brase, Sandra (Department: 2852)
Electrophotography
Document handling
Copy
C399S388000
Reexamination Certificate
active
06597889
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of image printing devices that use paper or a similar print media to print a hardcopy from electronic data or to make a copy of an original document. More particularly, the present invention relates to a dual paper picking device that increases the speed and reliability of the stream of print media being delivered from the paper or other print media supply to the image-printing device.
BACKGROUND OF THE INVENTION
Modern computers allow users to generate virtually any kind of document the user may desire. For example, word processing software allows a user to generate and easily edit text for documents. Spreadsheet, graphic design, desktop publishing or imaging software packages allow a user to generate or manipulate graphs, pictures, images, graphics, etc. The features and abilities of computer software continually evolve to provide the computer user with the ability to manage or generate data.
Though society is moving ahead into the digital age, for many applications it is still necessary or desirable to print a hardcopy of the documents generated on a computer. Consequently, printers have evolved along with computers to output high quality renderings on paper or other print media of the documents a user has generated on a computer.
In addition to printers, photocopiers allow users to quickly reproduce a document of which multiple copies are needed. Fax machines allow users to almost instantly transmit hardcopy documents over unlimited distances. Multi-Function Peripherals (“MFPs”) are devices that combine such functions as printing, copying, faxing and scanning.
As used herein, the term “image printing device” broadly denotes any device which outputs a hardcopy document on paper or some other print medium. For example, “image printing device” includes, but is not limited to, printers, photocopiers, fax machines, plotters, digital copiers and MFPs. The term “printer” refers broadly to any device that receives electrical data from a computer and outputs a hardcopy document corresponding to that data. Thus, “printer” refers, but is not limited to, electrostatic or laser printers, inkjet printers, thermal transfer printers, dot-matrix printers, plotters, etc.
All image-printing devices are fed a supply of a print medium, typically paper, on which the hardcopy document being output is rendered. While paper is the most widely used print medium, modern image printing devices can utilize a wide variety of print media including, but not limited to, paper, cardstock, transparencies, labels, etc. As used hereafter, the term “paper” shall be understood to refer principally to paper, but it will be understood that whenever an image-printing device is using paper as the print medium, any other print medium could also be used, consistent with any constraints imposed by the particular image-printing device in question.
For most image printing devices, regardless of the type of device, the modern trend is to adapt the image-printing device to accept and use a standard size of paper, for example, 8.5 inch by 11 inch paper or A4 paper. With all image-printing devices in an office using the same type of paper, the task of supplying the devices with paper is greatly simplified.
Additionally, the output speed and reliability of an image-printing device is heavily dependent on the ability of the device to feed itself the paper or other print medium used. For example, a printer cannot output printed pages any faster than it can pull in and position the paper to be printed on. Similarly, if the paper is mishandled, the printer will jam and stop, thereby causing further delays in the printing process. Consequently, the system for feeding paper or other print medium into an image-printing device is very important and critical to the speed and reliability of the device.
Unfortunately, there is often a trade off between speed and reliability in an image-printing device. For example, the faster the paper-feeding mechanism pulls sheets from a paper supply, the more likely it becomes that the fast moving paper will be mishandled and jam the image printing device. If the paper-feeding mechanism pulls sheets more slowly, the sheets are less likely to be mishandled, but the output speed of the image-printing device is correspondingly reduced.
Consequently, there is a need in the art for a device and method of increasing the ability of a paper-feeding mechanism to supply paper or another print medium to an image printing device at a high rate of speed without increasing the likelihood of mishandling the paper or other print medium and causing a printer error or paper jam.
SUMMARY OF THE INVENTION
The present invention is directed to a dual print medium picking mechanism for feeding print media from a supply of a print medium to an image-printing device. Specifically, the mechanism preferably includes a first print medium picking device for feeding print media from the supply to the image printing device; and a second print medium picking device for feeding print media from the supply to the image printing device.
The device of the present invention may include a single print medium transport path into which sheets of print medium are fed by both the first and second print medium picking devices. Alternatively, the device may include a first print medium transport path into which sheets of print medium are fed by the first print medium picking device; and a second print medium transport path into which sheets of print medium are fed by the second print medium picking device.
The present invention also encompasses the methods of making and using the dual print medium picking mechanism and image printing device described above. For example, the present invention includes a method of printing documents with an image printing device having a dual print medium picking mechanism, where the dual print medium picking mechanism includes a first print medium picking device for feeding print media from the supply to the image printing device; and a second print medium picking device for feeding print media from the supply to the image printing device. The method of the present invention is then performed by alternately picking sheets of print media from the supply with the first and second print medium picking devices and feeding the sheets of print media through the image printing device.
REFERENCES:
patent: 5069434 (1991-12-01), Sellers
patent: 5221951 (1993-06-01), Sakamoto
patent: 5327207 (1994-07-01), Otake et al.
patent: 5347350 (1994-09-01), Nakahata et al.
patent: 5359402 (1994-10-01), Nakahata et al.
patent: 5570451 (1996-10-01), Sakaizawa et al.
patent: 5729785 (1998-03-01), Sakaizawa et al.
Anderson Bradley J.
Johnson Bruce L.
Schroath Leonard T.
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