Sheet re-feed device and image forming apparatus
First Claim
1. An image forming apparatus comprising:
- sheet feed means for feeding sheets;
guide means for guiding the sheets fed by said sheet feed means to image forming means for forming an image on the sheet;
discharge guide means for discharging the sheets having an image formed thereon by said image forming means;
re-transportation guide means for branching the sheets from said discharge guide means and guiding the sheets through said image forming apparatus again; and
a plurality of sheet sensing devices disposed in said re-transportation guide means at intervals in a sheet transportation direction for determining positions at which the sheets are placed in a standby state, wherein a number of sheets, which are placed in said re-transportation guide means in the standby state, is determined based on sheet size information so that more sheets are placed in the standby state when a sheet size is short than when the sheet size is long.
1 Assignment
0 Petitions
Accused Products
Abstract
An image forming apparatus includes a guide unit for guiding sheets fed by a sheet feed unit to an image forming unit, a discharge guide unit for discharging the sheets onto which images are formed, by the image forming unit, a re-transportation guide unit for branching the sheets from the discharge guide unit and guiding them through the image forming apparatus again, and a plurality of sheet sensors disposed in the re-transportation guide unit at intervals in a sheet transportation direction for determining positions at which the sheets are placed in a standby state, wherein the number of sheets, which are placed in the standby state is selected based on sheet size information so that more sheets are placed in the standby state when a sheet size is short than when it is long. Accordingly, the throughput of short sheets can be increased when images are recorded on both sides thereof.
4 Citations
13 Claims
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1. An image forming apparatus comprising:
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sheet feed means for feeding sheets;
guide means for guiding the sheets fed by said sheet feed means to image forming means for forming an image on the sheet;
discharge guide means for discharging the sheets having an image formed thereon by said image forming means;
re-transportation guide means for branching the sheets from said discharge guide means and guiding the sheets through said image forming apparatus again; and
a plurality of sheet sensing devices disposed in said re-transportation guide means at intervals in a sheet transportation direction for determining positions at which the sheets are placed in a standby state, wherein a number of sheets, which are placed in said re-transportation guide means in the standby state, is determined based on sheet size information so that more sheets are placed in the standby state when a sheet size is short than when the sheet size is long. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A re-feed device comprising:
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re-transportation guide means for guiding sheets, which are branched after an image is formed thereon by an image forming means, to the image forming means again; and
a plurality of sheet sensing devices disposed in said re-transportation guide means at intervals in a sheet transporting direction for determining positions at which the sheets are placed in a standby state, wherein a number of sheets, which are placed in said re-transportation guide means in the standby state, is determined based on sheet size information so that more sheets are placed in the standby state when a sheet size is short than when the sheet size is long. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification