Image forming apparatus
An image forming apparatus includes: an exposure head including a light emitting portion that includes a first electrode layer including a plurality of electrodes that are two-dimensionally arranged in a main scanning direction and a sub-scanning direction, a light emitting layer stacked on the first electrode layer, and a second electrode layer through which light is transmissible; and a controller configured to control a voltage applied to each of the plurality of electrodes in such a way that the light emitting layer emits light, in which the plurality of electrodes for forming an identical pixel are arranged in such a way that the electrodes partially overlap each other when viewed from the rotation direction, and an inter-centroid distance of the plurality of electrodes in the rotational axis direction is equal in the rotational axis direction, and d3=W1/n (n is a natural number of 2 or more), in which W1 [mm] is a width of the electrode in the rotational axis direction, n is the number of electrodes for forming the identical pixel, and d3 [mm] is the equal inter-centroid distance in the rotational axis direction.
1 . An image forming apparatus for forming an image on a recording material, comprising:
a photosensitive member configured to rotate;
an exposure head having a plurality of light emitting portions arranged along a rotational axis direction of the photosensitive member; and
a controller configured to control the plurality of light emitting portions,
wherein the plurality of light emitting portions include n light emitting portions arranged at different positions in a rotation direction of the photosensitive member,
wherein the controller is configured to control the n light emitting portions such that one pixel is formed by the n light emitting portions; and
wherein the plurality of light emitting portions are arranged so that d3=q/n (where n is a natural number greater than or equal to 2), where q is a pitch of the light emitting portions adjacent to each other in the rotational axis direction, and d3 is the interval at which the n light emitting portions for forming the one pixel are arranged in the rotational axis direction.
2 . The image forming apparatus according to claim 1 ,
wherein the exposure head further comprises a substrate having an elongated shape and a light emitting chip mounted on the substrate and having a silicon substrate, and
the plurality of light emitting portions are formed on the silicon substrate.
3 . The image forming apparatus according to claim 2 ,
wherein the plurality of light emitting portions have a first electrode layer formed in a layered configuration and transmitting light, a second electrode layer formed in a layered configuration between the first electrode layer and the silicon substrate in a direction perpendicular to the surface of the silicon substrate and including a plurality of electrodes arranged in a two-dimensional configuration in the rotation direction and in the rotational axis direction, and a light-emitting layer formed between the first electrode layer and the second electrode layer in the direction perpendicular to the surface of the silicon substrate.
4 . The image forming apparatus according to claim 3 ,
wherein the image forming apparatus has a plurality of light emitting chips.
5 . The image forming apparatus according to claim 4 ,
wherein the plurality of the light emitting chips are disposed in a staggered arrangement along the rotational axis direction.
6 . The image forming apparatus according to claim 1 ,
wherein each of the n light emitting portions is not adjacent to one another in the rotational axis direction.
7 . The image forming apparatus according to claim 1 , wherein the controller controls lighting of the plurality of light emitting portions based on image data.
8 . The image forming apparatus according to claim 7 ,
wherein the image data is a set of binary bit data.