Patent ID: 8599234
Filing Date: 2013-12-03
Classification: B41J,G03G,H04N

Abstract:
1. An image forming apparatus comprising: an exposure device including an exposure head having a plurality of light-emitting points arranged in a main scanning direction; a photoconductor configured to be exposed to light emitted from the exposure device whereby an electrostatic latent image is formed thereon; a controller configured to control emission of the exposure device; and a memory configured to store an amount of shift C in a sub scanning direction of a position of each light-emitting point of the exposure head from a reference line extending in the main scanning direction, wherein the exposure head of the exposure device includes a plurality of light-emitting chips on which the plurality of light-emitting points are arranged in the main scanning direction, the plurality of light-emitting chips being arranged in positions such that adjacent light-emitting chips arranged in the main scanning direction are shifted from each other in position in a sub scanning direction that is a direction perpendicular to the main scanning direction, and wherein the controller includes: whereby points of exposure to light emitted from the light-emitting points are aligned substantially with a straight line extending in the main scanning direction on the photoconductor, and wherein the emission timing determination unit includes a tentative correction amount determination operation module configured to tentatively determine an amount of correction A for each light-emitting point based on a quotient obtained by dividing the amount of shift C stored in the memory by a quantization unit D, an inter-chip adjustment operation module configured to perform, if the following formula (1) is not satisfied for each pair of tentatively determined amounts of correction A where B is a difference |C 1 −C 2 | that is a difference between an amount of shift C 1 of a position of the light-emitting point (P 1 ) and an amount of shift C 2 of a position of the light-emitting point (P 2 ), ΔE is a value derived from |A 1 −A 2 | multiplied by the quantization unit D, in which |A 1 −A 2 | is the difference between the amount of correction A 1 for the light-emitting point (P 1 ) of the first light-emitting chip and the amount of correction A 2 for the light-emitting point (P 2 ) of the second light-emitting chip.