Optical writing unit, a driving method thereof, and an image forming apparatus
AssigneeRicoh Company, Ltd.
InventorKoji Masuda
Life of this patent
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Abstract
An optical writing unit is capable of producing a high-quality image in which the formation of white stripes and black stripes, due to uneven intervals between light emitting devices, is suppressed. The unevenness, often occurring at the junction part of two-light emitting diode array chips, is compensated for by increasing or decreasing the light volume of light emitting devices that are located on and near the edge of a light emitting device array chip, such that a property value concerning an exposure intensity distribution falls within a predetermined range for an effective image domain in its entirety.
Claims12
An optical writing unit, comprising:
- a light emitting device array comprising a plurality of light emitting device array chips, each of the light emitting device array chips comprising a plurality of light emitting devices that are arranged at a predetermined interval P;
- and
- an image forming device array comprising a plurality of image forming devices,
- wherein light volume of the light emitting devices is set such that a calculated gradient of an approximated linear regression for exposure areas corresponding to a plurality of the light emitting devices that are selected at a predefined cycle falls within a predetermined range, the predetermined range being defined for an effective image area in its entirety, and
- the light volume of the light emitting devices that are located closest and next closest to an edge of the light emitting device array chips are set up such that said gradient corresponds to an interval Pa between the light emitting device closest to the edge of one of the light emitting device array chips and the light emitting device closest to the edge of an adjacent one of the light emitting device array chips.
An image forming apparatus for forming an image, comprising:
- an exposure unit comprising an image forming device array and a light emitting device array, the light emitting device array comprising a plurality of light emitting device array chips, each of the light emitting device array chips comprising a plurality of light emitting devices arranged at a predetermined interval,
- wherein the light volume of each of the light emitting devices is set up such that a calculated gradient of an approximated linear regression of exposure areas corresponding to a plurality of the light emitting devices that are selected based on a predetermined cycle falls within a predetermined range for an effective image domain in its entirety, and
- the light volume of each of the light emitting devices closest and next closest to the edge of the light emitting device array chip is set up such that said gradient corresponds to an interval between the light emitting device closest to the edge of one of the light emitting device array chips and the light emitting device closest to the edge of an adjacent one of the light emitting device array chips.
A driving method for driving an optical writing unit comprising an exposure unit, the exposure unit comprising a light emitting device array, the light emitting device array comprising a plurality of light emitting device array chips, each of the light emitting device array chips comprising a plurality of light emitting devices arranged at a predetermined interval, the image forming device array comprising a plurality of image forming devices, the driving method comprising:
- setting the light volume of each of the light emitting devices such that a calculated gradient of an approximated linear regression of exposure areas corresponding to a plurality of the light emitting devices that are selected based on a predetermined cycle falls within a predetermined range for an effective image domain in its entirety, and
- wherein the light volume of each of the light emitting devices closest and next closest to the edge of the light emitting device array chip is set up such that said gradient corresponds to an interval between the light emitting device closest to the edge of one of the light emitting device array chips and the light emitting device closest to the edge of an adjacent one of the light emitting device array chips.
Dependencies are inferred from the claim text.