Laser driving unit and image forming apparatus
AssigneeRicoh Company, Ltd.
InventorsAtsufumi Omori, Masaaki Ishida
Life of this patent
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Abstract
A laser driving unit drives a semiconductor laser apparatus including a plurality of light sources, includes a light detecting part to detect light emissions from the light sources, a driving current generator to generate a driving current based on an input signal, an auxiliary driving current generator to generate an auxiliary driving current in an initial time period of an ON-time of the driving current, and an auxiliary current set part to set an auxiliary amount of the auxiliary driving current to be added to the driving current, for each of the light sources, based on a difference between the light emissions detected by the light detecting part and a target light emission of the light sources.
Claims25
A laser driving unit configured to drive a semiconductor laser apparatus including a plurality of light sources, comprising:
- a light detecting unit configured to detect light emissions from the plurality of light sources;
- a bias current generator configured to generate a bias current lower than or equal to a threshold current of the plurality of light sources;
- a modulation current generator configured to generate a modulation current, to cause light emission of the plurality of light sources, depending on a modulation signal;
- an auxiliary driving current generator configured to generate an auxiliary driving current to assist the modulation current during an initial time period of an ON-time of the modulation current, wherein a driving current to drive each of the plurality of light sources includes the bias current, the modulation current, and the auxiliary driving current;
- and
- an auxiliary current set unit configured to set an auxiliary amount of the auxiliary driving current to be added to the modulation current, for each of the plurality of light sources, based on a difference between a target light emission of the plurality of light sources and the light emission detected by the light detecting unit when the plurality of light sources are driven by the driving current.
An image forming apparatus comprising:
- a photoconductive body;
- a plurality of light sources configured to emit beams that scan the photoconductive body;
- and
- a laser driving unit configured to drive the plurality of light sources,
- wherein the laser driving unit comprises:
- a light detecting unit configured to detect light emissions from the plurality of light sources;
- a bias current generator configured to generate a bias current lower than or equal to a threshold current of the plurality of light sources;
- a modulation current generator configured to generate a modulation current, to cause light emission of the plurality of light sources, depending on a modulation signal;
- an auxiliary driving current generator configured to generate an auxiliary driving current to assist the modulation current during an initial time period of an ON-time of the modulation current, wherein a driving current to drive each of the plurality of light sources includes the bias current, the modulation current, and the auxiliary driving current;
- and
- an auxiliary current set unit configured to set an auxiliary amount of the auxiliary driving current to be added to the modulation current, for each of the plurality of light sources, based on a difference between a target light emission of the plurality of light sources and the light emission detected by the light detecting unit when the plurality of light sources are driven by the driving current.
Dependencies are inferred from the claim text.