Light-source control device, light-source control method, image reading device, and image forming apparatus
AssigneeRicoh Company, Ltd.
InventorTadaaki Oyama
Life of this patent
Estimating the term…
Abstract
A light-source control device includes a light source including a first light emitter for emitting light and a second light emitter for emitting light due to the light emitted by the first light emitter; a constant current unit configured to maintain a current constant that is input via the light source from a power supply; a switching unit configured to switch the current to be input to the constant current unit at a designated duty ratio and cycle; and a control unit configured to control the current applied to the light source so that a rise transition time and a fall transition time of the current applied to the light source are nearly equal to each other.
Claims15
A light-source control device comprising:
- a light source having a load current applied thereto, the light source including a first light emitter for emitting light and a second light emitter for emitting light by exciting material therein in response to the light emitted by the first light emitter;
- a control unit configured to control the load current applied to the light source so that a rise transition time and a fall transition time of the load current applied to the light source are nearly equal to each other;
- a constant current maintaining unit configured to maintain a source current, input via the light source and the control unit from a power supply, at a constant magnitude, the source current being based on the load current;
- and
- a switching unit configured to switch the source current input, via the light source and the control unit, to the constant current maintaining unit at a designated duty ratio and cycle.
A light-source control device comprising:
- a light source having a load current applied thereto, the light source including a first light emitter for emitting light and a second light emitter for emitting light by exciting material therein in response to the light emitted by the first light emitter;
- a control means for controlling the load current applied to the light source so that a rise transition time and a fall transition time of the load current applied to the light source are nearly equal to each other;
- a constant current maintaining means for maintaining a source current, input via the light source and the control means from a power supply, at a constant magnitude, the source current being based on the load current;
- and
- a switching means for switching the source current input, via the light source, to the constant current maintaining means at a designated duty ratio and cycle.
A light-source control method comprising:
- maintaining, by a constant current maintaining unit, a source current, input via a light source from a power supply, at a constant magnitude, the light source having a load current applied thereto, the light source including a first light emitter for emitting light and a second light emitter for emitting light by exciting material therein in response to the light emitted by the first light emitter;
- switching the source current input, via the light source, to the constant current maintaining unit at a designated duty ratio and cycle;
- and
- controlling the load current applied to the light source so that a rise transition time and a fall transition time of the load current applied to the light source are nearly equal to each other.
Dependencies are inferred from the claim text.