Image forming apparatus having a counting device to facilitate two-sided copying
AssigneeCanon Kabushiki Kaisha
InventorsAkihiro Kasiwabara, Mitsuhiro Mukasa
Life of this patent
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Abstract
An image forming apparatus, in which sheets on which image formation has been effected are once contained in an intermediate tray for second image formation and the sheets contained in the intermediate tray are re-fed to an image forming portion of the image forming apparatus to thereby effect plural times of image formation on a sheet, is characterized by a counting device for counting the sheets contained in the intermediate tray.
Claims33
An image forming apparatus having an image forming portion, said image forming apparatus comprising:
- an intermediate tray for containing sheets on which image formation has been effected, for another image formation, the sheets then being re-fed to the image forming portion to thereby effect plural times of image formation on the sheets;
- and
- counting means for counting the sheets contained in said intermediate tray, said counting means comprising a circulation path for returning the sheets fed out from said intermediate tray to said intermediate tray without passing the sheets through the image forming portion, and a counter for counting the sheets passing through said circulation path.
An image forming apparatus comprising:
- image forming means for forming images on sheets;
- containing means for containing therein the sheets on which the images have been formed by said image forming means;
- feeding means for feeding the sheets contained in said containing means to said image forming means;
- conveyance abnormality detecting means for detecting a conveyance abnormality of the sheets in the apparatus;
- counting means for counting the sheets in said containing means;
- and
- control means for controlling such that when the conveyance abnormality is detected by said conveyance abnormality detecting means, said feeding means is stopped, the sheets in said containing means are counted by said counting means, images are formed on sheets on which no image is formed by said image forming means in conformity with the count value of said counting means, and the sheets are contained in said containing means.
An image forming apparatus comprising:
- image reading means for reading the images of originals;
- supplying means for supplying the originals to said image reading means;
- image forming means for forming the images read by said image reading means on sheets;
- containing means for containing therein the sheets on which the images have been formed by said image forming means;
- feeding means for feeding the sheets contained in said containing means to said image forming means;
- conveyance abnormality detecting means for detecting a conveyance abnormality of the sheets in the apparatus;
- counting means for counting the sheets in said containing means;
- and
- control means for controlling such that when the conveyance abnormality is detected by said conveyance abnormality detecting means, said feeding means may be stopped, the sheets in said containing means may be counted by said counting means, deficient sheets and originals having thereon images to be formed on said deficient sheets may be discriminated by the count value of said counting means, the originals having thereon the images to be formed on said deficient sheets may be supplied to said image reading means by said supplying means, the images of said originals may be read by said image reading means and be formed on the sheets by said image forming means, and said sheets may be contained in said containing means.
In an image forming apparatus wherein N sheets on which a first image formation has been effected are once contained in an intermediate tray for a second image formation and the sheets contained in said intermediate tray are re-fed to an image forming portion to thereby effect the second image formation on the same sheets, a recovery method when an accident occurs to the re-fed sheets and the re-fed sheets are removed, comprising the steps of:
- a first step of counting a number n.sub.1 of the sheets re-fed from said intermediate tray and on which the second image formation has been completed, and a number n.sub.2 of the sheets remaining in said intermediate tray;
- a second step of effecting the image formation effected on the (n.sub.1 +1)th to (n.sub.2 -1)th sheets during the first image information on (N-n.sub.1 -n.sub.2) new sheets;
- a third step of containing in said intermediate tray the sheets on which the first image formation has been effected at the second step;
- a fourth step of adjusting the order of the sheets in said intermediate tray so that the sheets contained in said intermediate tray may be re-fed in the order from the (n.sub.1 +1)th to Nth sheets;
- and
- a fifth step of re-feeding the sheets contained in said intermediate tray to the image forming portion.
Dependencies are inferred from the claim text.