Electrophotography – Document handling – Copy
Utility Patent
1998-05-29
2001-01-02
Braun, Fred L. (Department: 2852)
Electrophotography
Document handling
Copy
Utility Patent
active
06169875
ABSTRACT:
FIELD OF INVENTION
This invention relates generally to imaging of envelopes and, more specifically, to an envelope transport structure that minimizes wrinkling of envelopes during an imaging process.
BACKGROUND OF THE INVENTION
In electrostatic or electrophotographic image forming apparatus, such as monochrome and color laser printers and photocopiers, it is common to fuse a loose toner image by passing the imaged media through a fusing nip. The fusing nip is typically formed from a first fusing roller urged against a second fusing roller to create a pressurized nip through which the media passes. One or both of the fusing rollers are typically heated to increase the temperature within the nip.
In those imaging systems utilizing a fusing nip as described above, wrinkling of envelopes within the fusing nip has been a continuing problem. Previous attempts to reduce envelope wrinkling have involved relieving the pressure on the envelopes at various points in the fusing operation. An example of this approach is found in U.S. Pat. No. 5,268,726 to Oleksa et al.
It is also known to utilize individual support ribs or fingers within a paper path to reduce friction between the moving media and the surfaces of the paper path. The support fingers also serve to lessen pre-heating of the media due to heat transfer from the support surfaces of the paper path. Additionally, to prevent any one point on the image from being in extended continuous contact with a single support finger, the fingers may be angled with respect to the direction of travel of the media. This helps to avoid uneven heating of the media and image that can cause print defects and variations in the gloss of the printed image.
It is also known to angle the support fingers away from the center line of the paper path to prevent the leading corners of a media sheet from catching the sides of the fingers and pushing the media laterally to either side of the paper path. Should the media be pushed laterally prior to the fusing nip, wrinkling can occur and, in a worst case scenario, a paper jam may be created. An example of utilizing support fingers that are canted away from the center line of the paper path is found in U.S. Pat. No. 5,870,661 entitled APPARATUS AND METHOD FOR CONTROLLING MEDIA TEMPERATURE IN AN IMAGING APPARATUS and assigned to the assignee of the present application.
It has been found that support fingers that are canted away from the center line of the paper path have a disadvantage when printing envelopes. When the addressee side of an envelope is printed and the envelope travels along the paper path, the flap of the envelope on the opposite side hangs down at an angle that is canted away from the center line of the paper path, similar to the angle of the canted support fingers. As the envelope travels over the support fingers, the flap may catch the side of a finger and cause the envelope to be pushed laterally to the side or opened while moving through the fuser. This can cause severe wrinkling, print defects, and/or a media jam.
The present invention seeks to overcome the disadvantages of previous implementations of canted support fingers by changing the angle of the support fingers directly under the envelope to prevent the envelope flap from catching the side of a support finger. More specifically, the support fingers directly under the envelope in a central area are canted toward the center line of the paper path to allow the envelope flap to pass over the support fingers at an angle oblique to the angle of the support fingers. The support fingers on either side of the area over which the envelope passes are canted away from the center line of the paper path to prevent the corners of full width media from catching the surface of a rib. Accordingly, a reduction in wrinkling of both envelopes and full width media is achieved with a simple, low-cost structure.
SUMMARY OF THE INVENTION
It is an aspect of the present invention to provide a media transport unit including an envelope transport structure for supporting an envelope traveling along a media path in an imaging apparatus.
It is another aspect of the present invention that the media transport unit utilizes a plurality of media supports grouped in a first lateral portion, a second lateral portion, and a center portion between the first and second lateral portions.
It is a feature of the present invention that the center portion of media supports are canted toward the center line of the media path to allow an envelope flap to travel over the media supports without being urged laterally by a support.
It is another feature of the present invention that the media supports in the first and second lateral portions are canted away from the center line of the media path to prevent the leading corners of a full width media sheet from catching a media support and pushing the media laterally.
It is an advantage of the present invention that the envelope transport structure allows the use of individual media supports in the paper path while also preventing media and envelope wrinkling.
It is another advantage of the present invention that the envelope transport structure comprises a simple and compact design that utilizes low-cost components.
Still other aspects, features, and advantages of the present invention will become apparent to those skilled in this art from the following description, wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modifications in various, obvious aspects, all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. And now for a brief description of the drawings.
REFERENCES:
patent: 4493548 (1985-01-01), Ateya
patent: 4525057 (1985-06-01), Kaufmann et al.
patent: 4843214 (1989-06-01), Higashi et al.
patent: 4958195 (1990-09-01), Firth, III et al.
patent: 5130752 (1992-07-01), Morishita et al.
patent: 5166737 (1992-11-01), Tomito
patent: 5268726 (1993-12-01), Oleksa et al.
patent: 5450187 (1995-09-01), Pei et al.
patent: 5618375 (1997-04-01), Suzuki et al.
patent: 5678160 (1997-10-01), Williams
patent: 5870661 (1999-02-01), Menzel et al.
patent: 6-292152 (1988-11-01), None
Braun Fred L.
Walder Jeannette M.
Xerox Corporation
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