Electrophotography – Document handling – Copy
Reexamination Certificate
2000-02-18
2001-09-18
Lee, Susan S. Y. (Department: 2852)
Electrophotography
Document handling
Copy
C399S406000
Reexamination Certificate
active
06292650
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus used as an electrophotographic copying machine.
A paper sheet is usually discharged from a copying machine main body onto a discharge-paper tray projecting from the copying machine main body. In recent years, however, to save space, an intra paper-discharge type of copying machine having the paper-discharge tray within the main body, has been in the mainstream.
Another type of the copying machine is known which has an automatic inverting unit for attaining two-sided copy. The automatic inverting unit is arranged within a main body in the copying machine in which a paper discharge tray projects therefrom, whereas it is attached to an outer side surface portion of the copying machine main body in the intra-discharge type copying machine.
When the two-sided copy is made, the paper sheet on the upper surface side of which an image is copied in an image transfer section, is fed into the automatic inverting unit. The paper sheet is then inverted by the automatic inverting unit and again fed into the image transfer section to transfer an image onto the rear surface side of the paper.
In some copying machines of the intra-discharge type, the paper sheets having an image on the upper surface side are discharged outside from a paper-discharge roller pair in a predetermined amount, and thereafter, taken into the copying machine and sent into the automatic inverting unit by rotating the discharge roller pair in a reverse direction, whereby a two-sided copy can be made.
The paper-discharge roller pair plays a role in corrugating the paper sheet when the paper sheet is discharged through the paper-discharge roller pair. As a result, the paper sheet discharged onto the paper-discharge section acquires structural strength and improved in alignment.
However, when the corrugated paper sheet is returned again to the copying machine main body and fed to the automatic inverting unit to make a rear-side copy, if the paper is corrugated strongly in order to improve the alignment properties of the discharged paper sheet, the paper sheet comes into collusion with a photosensitive drum, leading to a paper jam. Alternatively, the paper sheet is pressed against the photosensitive drum to produce wrinkle at the time of copying the rear surface thereof.
Therefore, in the conventionally-used machine, the paper sheet is weakly corrugated to prevent occurrence of the paper jam or wrinkle at the time copy is made on the rear surface of the paper sheet. However, when the paper sheet is weakly corrugated, there is a problem in that the alignment of the discharged paper sheet decreases.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide an image forming apparatus without occurrence of a paper jam and wrinkle even if a medium is strongly corrugated by a discharging means.
According to the present invention, there is provided an image forming apparatus comprising:
transfer means arranged in an apparatus main body, for transferring an image onto a medium;
discharging means for transferring the medium having the image transferred by the transfer means on one side thereof to corrugate the medium and discharging the medium as it is from the apparatus main body at the time a single-sided image is formed or taking the medium into the apparatus main body instead of discharging the medium at the time a two-sided image is formed;
re-transfer means for re-transferring the medium taken into the apparatus main body by the discharging means towards the transfer means while keeping an inverted state; and
stretching means for stretching the medium transferred by the re-transfer means in a direction of canceling the corrugation.
An image forming apparatus according to the present invention comprises:
transfer means arranged in an apparatus main body, for transferring an image onto a medium;
discharging means for transferring the medium having the image transferred by the transfer means on one side thereof to corrugate the medium and discharging the medium as it is from the apparatus main body at the time a single-sided image is formed or taking the medium into the apparatus main body instead of discharging the medium at the time a two-sided image is formed;
re-transfer means for re-transferring the medium taken into the apparatus main body by the discharging means towards the transfer means while keeping an inverted state; and
stretching means for stretching the medium transferred by the re-transfer means in a direction of canceling the corrugation.
wherein the re-transferring means has a transfer roller pair arranged at a predetermined interval in a direction perpendicular to a transfer direction of the medium, and
the stretching means is constituted by arranging one of the transfer roller pair so as to incline to a direction perpendicular to the transfer direction of the medium.
An image forming apparatus according to the present invention comprises:
transfer means arranged in an apparatus main body, for transferring an image onto a medium;
discharging means for transferring the medium having the image transferred by the transfer means on one side thereof to corrugate the medium and discharging the medium as it is from the apparatus main body at the time a single-sided image is formed or taking the medium into the apparatus main body instead of discharging the medium at the time a two-sided image is formed;
re-transfer means for re-transferring the medium taken into the apparatus main body by the discharging means towards the transfer means while keeping an inverted state; and
stretching means for stretching the medium transferred by the re-transfer means in a direction of canceling the corrugation.
wherein the re-transfer means has a transfer roller pair which are arranged along a direction perpendicular to a transfer direction of the medium, for transferring the medium by holding an entire width of the medium; and
the stretch means is constituted by gradually increasing an diameter of one of the transfer roller pair from a center thereof towards right and left edges.
REFERENCES:
patent: 1685873 (1928-10-01), Evans et al.
patent: 3954261 (1976-05-01), Greene et al.
patent: 4806979 (1989-02-01), Tokoro et al.
patent: 4809968 (1989-03-01), Malachowski
patent: 5153663 (1992-10-01), Bober et al.
patent: 5162857 (1992-11-01), Higeta et al.
patent: 5209466 (1993-05-01), Watts et al.
patent: 5515152 (1996-05-01), Kuo
patent: 5724642 (1998-03-01), Cala
patent: 6032945 (2000-03-01), Miura
patent: 6094561 (2000-07-01), Ushio
patent: 5-24746 (1993-02-01), None
Foley & Lardner
Lee Susan S. Y.
Toshiba Tec Kabushiki Kaisha
LandOfFree
Image forming apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image forming apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image forming apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2545995