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US 11,198,571 B2Granted
Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorSho Ota
Life of this patent
Estimating the term…
Abstract
An image forming apparatus includes a control unit and an attachment detection unit to detect attachment of a cassette having a stacking portion that may be lifted by a motor. The control unit drives the motor to start lifting the stacking portion when cassette attachment is detected and stops when the stacked uppermost sheet is detected at a sheet feed position, at which time the presence or absence of the stored sheet is determined based on a detection signal output by a sheet presence/absence detection unit. In a case where there is no change in the detection signal output from the sheet presence/absence detection unit when the attachment of the cassette is detected, the control unit determines that a failure of the sheet presence/absence detection flag occurred.
Claims15
An image forming apparatus comprising:
- a cassette drawably attached to an apparatus main body and configured to store a sheet;
- an attachment detection unit configured to detect attachment of the cassette;
- a stacking portion provided in the cassette and on which the sheet is to be stacked;
- a motor configured to lift the stacking portion;
- a feeding roller configured to feed the sheet stacked on the stacking portion;
- an image forming unit configured to form an image on the sheet fed by the feeding roller;
- a sheet surface detection unit configured to detect that an uppermost sheet stacked on the stacking portion is at a sheet feed position;
- a sheet presence/absence detection unit configured to detect presence or absence of the sheet stacked on the stacking portion, wherein the sheet presence/absence detection unit includes a sheet presence/absence detection flag provided in the apparatus main body and is configured to turn in association with the attachment of the cassette;
- and
- a control unit configured to drive the motor to start lifting the stacking portion when the attachment of the cassette is detected by the attachment detection unit, to stop lifting the stacking portion in a case where the sheet surface detection unit detects that the uppermost sheet stacked on the stacking portion is at the sheet feed position and, after lifting the stacking portion is stopped, to determine presence or absence of the sheet stored in the cassette based on a detection signal output from the sheet presence/absence detection unit,
- wherein, in a case where it is determined that there is no change in the detection signal output from the sheet presence/absence detection unit from when the attachment of the cassette is not detected by the attachment detection unit to when the attachment of the cassette is detected by the attachment detection unit, the control unit determines that a failure of the sheet presence/absence detection flag has occurred.
8 more elements
An image forming apparatus comprising:
- a cassette drawably attached to an apparatus main body and configured to store a sheet;
- an attachment detection unit configured to detect attachment of the cassette;
- a stacking portion provided in the cassette and on which the sheet is to be stacked;
- a motor configured to lift the stacking portion;
- a feeding roller configured to feed the sheet stacked on the stacking portion;
- an image forming unit configured to form an image on the sheet fed by the feeding roller;
- a sheet surface detection unit configured to detect that an uppermost sheet stacked on the stacking portion is at a sheet feed position;
- a sheet presence/absence detection unit configured to detect presence or absence of the sheet stacked on the stacking portion, wherein the sheet presence/absence detection unit includes a sheet presence/absence detection flag provided in the apparatus main body and is configured to turn in association with the attachment of the cassette;
- and
- a control unit configured to drive the motor to start lifting the stacking portion when the attachment of the cassette is detected by the attachment detection unit, to stop lifting the stacking portion in a case where the sheet surface detection unit detects that the uppermost sheet stacked on the stacking portion is at the sheet feed position and, after lifting the stacking portion is stopped, to determine that the sheet is absent in a case where a detection signal output from the sheet presence/absence detection unit is a first detection signal, and determine that the sheet is present in a case where the detection signal output from the sheet presence/absence detection unit is a second detection signal,
- wherein, in a case where the detection signal output from the sheet presence/absence detection unit is the first detection signal and a time from start to end of lifting the stacking portion is shorter than a threshold value, the control unit determines that a failure of the sheet presence/absence detection flag has occurred.
8 more elements
Dependencies are inferred from the claim text.