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US 10,474,055 B2Granted
Image forming apparatus adjusting driving current for emitting light
AssigneeCanon Kabushiki Kaisha
InventorYasukazu Maeda
Life of this patent
Estimating the term…
Abstract
A period in which an adjustment unit adjusts a driving current such that the light irradiation unit emits a third light emission amount of light is switched to a period in which a light irradiation unit emits a second light emission amount of light, and the period in which the light irradiation unit emits the second light emission amount of light is switched to a period in which the light irradiation unit emits a first light emission amount of light.
Claims15
An image forming apparatus comprising:
- one or more processors;
- and
- one or more memories storing instructions, when executed by the one or more processors, causing the information forming apparatus to function as:
- a charging unit configured to charge a photosensitive member;
- a light irradiation unit configured to emit a first light emission amount of light for forming an electrostatic latent image in an image portion, a second light emission amount of light for controlling a potential of a non-image portion, and a third light emission amount of light,
- wherein the second light emission amount is smaller than the first light emission amount, and the third light emission amount is smaller than the second light emission amount;
- a detection unit configured to detect a light emission intensity of the light emitted from the light irradiation unit;
- a control unit;
- and
- an adjustment unit configured to adjust a driving current to be supplied to the light irradiation unit based on the light emission intensity detected, so as to adjust an amount of the light emitted from the light irradiation unit,
- wherein the adjustment unit includes a first adjustment unit configured to adjust a first driving current to adjust the first light emission amount, a second adjustment unit configured to adjust a second driving current to adjust the second light emission amount and a third adjustment unit configured to adjust a third driving current to adjust the third light emission amount,
- wherein the first adjustment unit is configured to adjust, in a first period, the first driving current at timing at least before detection of a horizontal synchronization signal,
- wherein the second adjustment unit is configured to adjust, in a second period, the second driving current in a period at least after the detection of the horizontal synchronization signal and at least part of an image mask period, and
- wherein the third adjustment unit is configured to adjust, in a third period, the third driving current in a period after the second driving current is adjusted,
- wherein the control unit switches to a fourth period subsequent to the third period and switches to a fifth period subsequent to the fourth period,
- wherein the fourth period is a period in which the second emission amount of light is emitted from the light irradiation unit based on the second driving current adjusted by the second adjustment unit, and
- wherein the fifth period is a period in which the first emission amount of light is emitted from the light irradiation unit based on the first driving current adjusted by the first adjustment unit.
14 more elements
An image forming apparatus comprising:
- a charging unit configured to charge a photosensitive member;
- a light irradiation unit configured to emit a first light emission amount of light for forming an electrostatic latent image in an image portion, a second light emission amount of light for controlling a potential of a non-image portion, and a third light emission amount of light,
- wherein the second light emission amount is smaller than the first light emission amount, and the third light emission amount is smaller than the second light emission amount;
- a detection unit configured to detect a light emission intensity of the light emitted from the light irradiation unit;
- a control unit configured to acquire the third light emission amount based on a use state of the first light emission amount and the second light emission amount;
- and
- a switching unit configured to switch between a first state in which a driving current obtained by adding a first driving current, a second driving current, and a third driving current is supplied to the light irradiation unit so that the light irradiation unit emits the first light emission amount of light, a second state in which the driving current obtained by adding the second and third driving currents without adding the first driving current is supplied to the light irradiation unit so that the light irradiation unit emits the second light emission amount of light, and a third state in which the third driving current is supplied as the driving current to the light irradiation unit without adding the first and second driving current so that the light irradiation unit emits the third light emission amount of light,
- wherein the control unit is configured to switch the light irradiation unit to, subsequent to a period of emitting at least the third light emission amount of light, a period of emitting the second light emission amount of light, and
- wherein the control unit further switches to, subsequent to a period of emitting the second light emission amount of light, a period of emitting the first light emission amount of light.
6 more elements
Dependencies are inferred from the claim text.