Back to results
US 2026/0084445 A1Published application
Edge portion detection method and liquid ejection apparatus
AssigneeCanon Kabushiki Kaisha
InventorsKenji Kubozono, Keita Tamiya
Life of this patent
Estimating the term…
Abstract
A technique for detecting a medium's edge portion with high accuracy is provided. To this end, a liquid ejection apparatus adjusts a differential output by having a plurality of light reception units, obtaining a differential output based on outputs from the plurality of light reception units, and adjusting the light reception sensitivity of the light reception units using an adjustment unit.
Claims17
An edge portion detection method for detecting an edge portion of a sheet in terms of a width direction of the sheet using a detection unit provided at a carriage movable in the width direction, wherein
- the detection unit has a light emission unit, a light reception unit including a first light reception unit including a plurality of light-receiving devices configured to receive light emitted from the light emission unit and then reflected and a second light reception unit disposed at a position away from the first light reception unit in the width direction and including a plurality of light-receiving devices configured to receive light emitted from the light emission unit and then reflected, and a differential amplification circuit unit configured to amplify a difference between an output signal from the first light reception unit and an output signal from the second light reception unit, and
- the method comprises:
- an adjustment step of adjusting a differential output from the differential amplification circuit unit,
- an obtainment step of, while moving the carriage, obtaining the differential output from the differential amplification circuit unit adjusted in the adjustment step;
- and
- a detection step of detecting an edge portion of the sheet based on a change in the differential output relative to a position of the carriage obtained in the obtainment step.
3 more elements
An edge portion detection method employed by a liquid ejection apparatus including
- a conveyance unit configured to convey a printing medium,
- a moving unit configured to move a carriage in a scan direction intersecting with a conveyance direction in which the printing medium is conveyed by the conveyance unit, and
- a detection unit provided at an end portion of the carriage in terms of the scan direction and having a light emission unit configured to apply light to the printing medium, a light reception unit having a plurality of light-receiving devices configured to receive light reflected by the printing medium, and an amplification circuit unit configured to amplify an output signal from the light reception unit, and
- a control unit having an adjustment unit configured to adjust an output signal from the detection unit, the controlling unit being configured to control the detection unit, the method comprising:
- a first adjustment step in which, in a first operation mode of the amplification circuit unit, a first light reception unit of the light reception unit receives light reflected by the printing medium conveyed by the conveyance unit, and the adjustment unit makes an adjustment on an output signal from the detection unit;
- a switch step in which the control unit switches the first operation mode of the amplification circuit unit to a second operation mode different from the first operation mode;
- a second adjustment step in which, in the second operation mode, the adjustment unit adjusts an output signal from the detection unit in an event where a second light reception unit of the light reception unit different from the first light reception unit receives light reflected by the printing medium based on the adjustment made in the first adjustment step;
- and
- an edge portion detection step in which, in the second operation mode, an edge portion of the printing medium is detected by an output signal from the detection unit adjusted in the second adjustment step.
6 more elements
A liquid ejection apparatus comprising:
- a carriage carrying a liquid ejection head and movable in a width direction of a sheet and a detection unit provided at the carriage, wherein
- the detection unit has a light emission unit, a light reception unit including a first light reception unit including a plurality of light-receiving devices configured to receive light emitted from the light emission unit and then reflected and a second light reception unit disposed at a position away from the first light reception unit in the width direction and including a plurality of light-receiving devices configured to receive light emitted from the light emission unit and then reflected, and a differential amplification circuit unit configured to amplify a difference between an output signal from the first light reception unit and an output signal from the second light reception unit, and
- the liquid ejection apparatus further comprises an adjustment unit configured to adjust the differential output from the differential amplification circuit unit.
Dependencies are inferred from the claim text.