Provided are: an exposure device being configured to perform multiple exposure with the second light-emitting element array to a place exposed with the first light-emitting element array; and a controller configured to transmit a signal for controlling the exposure device, in which the exposure device sets a first pulse signal for light emission of the first light-emitting element array, based on a first delay time and a first pulse width, sets a second pulse signal for light emission of the second light-emitting element array, based on a second delay time, different from the first delay time, and a second pulse width, identical to the first pulse width, and starts and terminates light emission of each of the first light-emitting element array and the second light-emitting element array, according to the set first pulse signal and second pulse signal.

An image forming apparatus includes a housing having an opening, a cover movable between an open position and a closed position, a first photoconductive drum and a second photoconductive drum, a first exposing head having a first boss and rotatably coupled to the cover, a second exposing head having a second boss and rotatably coupled to the cover, and a cam rotatably coupled to each of the first exposing head and the second exposing head. The cam is configured to rotate each of the first exposing head and the second exposing head. The cam includes (i) a first elongated hole into which the first boss fits and extending a direction intersecting a movement direction in which the cam moves and (ii) a second elongated hole into which the second boss fits and extending in a direction intersecting the movement direction of the cam.

An image forming apparatus configured to perform high-quality image formation regardless of an accuracy of mounting surface emitting element array chips includes an image data generating portion configured to generate pixel data equivalent to 2,400 dpi; a joint correcting portion configured to correct a misregistration amount at a joint between a predetermined surface emitting element array chip and a surface emitting element array chip arranged adjacent to the predetermined surface emitting element array chip; and a resolution converting portion configured to convert a resolution of the pixel data from 2,400 dpi to 1,200 dpi. The joint correcting portion is configured to correct the misregistration amount at the joint with respect to pixel data obtained after the resolution thereof is converted by the resolution converting portion.

A printhead in a digital printing includes an array of light sources for exposing a photosensitive medium moving past the printhead. Artifacts are reduced in a high-speed print mode by defining first and a second power level control values that differ by at least 20%. The light sources used to print odd-numbered image pixels are activated responsive to the first power level control value and the light sources used to print even-numbered image pixels are activated responsive to the second power level control value.

An optical print head comprises a first light emitting element row, a second light emitting element row, a lens array, a first drive circuit and a second drive circuit. The first light emitting element row includes the arrangement of first light emitting elements. The second light emitting element row includes second light emitting elements arranged in parallel with the first light emitting element row. The lens array concentrates light emitted by the first light emitting elements and the second light emitting elements. The first drive circuit drives each first light emitting element with an identical first current value. The second drive circuit drives each second light emitting element with an identical second current value different from the first current value.

A hierarchical printhead system supports multiple print modes. A first print mode uses a first subset of light sources having a first spacing. A second print mode uses a second subset of light sources having a second spacing which is less than the first spacing. Image data for lines of image data are sequentially loaded into the printhead, wherein if the specified print mode is the first print mode, image data for a first group of light sources corresponding to the first subset are loaded, and if the specified print mode is the second print mode, image data for the first group of light sources are first loaded, and then image data for a second group of light sources corresponding to the light sources in the second subset that are not in the first subset are loaded.

Provided is an image erasing method including heating a thermoreversible recording medium with laser beams to erase an image which has been recorded on the thermoreversible recording medium, the thermoreversible recording medium reversibly changing between a colored state and a decolored state depending on a heating temperature and a cooling time; and measuring at least one of a surface temperature of the thermoreversible recording medium and an erasing environmental temperature before a beginning of erasing the image to obtain a measured temperature value and controlling a heating time with the laser beams to be emitted for erasing the image depending on the measured temperature value.

An image forming apparatus includes: an exposure head including a first light emitting chip, a second light emitting chip, a first lens fixed to a housing at a position facing the first light emitting chip, and configured to form an image of light emitted from a plurality of light emitting portions included in the first light emitting chip on a photoreceptor, and a second lens provided separately from the first lens, fixed to the housing at a position facing the second light emitting chip, and configured to form an image of light emitted from a plurality of light emitting portions included in the second light emitting chip on the photoreceptor; and a controller capable of controlling application of a voltage to each of a plurality of electrodes of the first light emitting chip and a plurality of electrodes of the second light emitting chip so as to form one pixel.

A light emitting device includes a light emitting unit in which a resin housing extending in one direction holds a light emitting element emitting light in a light emitting direction intersecting the one direction, a suppressing member that extends in the one direction and suppresses deformation of the housing caused by heat, the suppressing member having a linear expansion coefficient different from a linear expansion coefficient of the housing, and a fixing portion that fixes the housing and the suppressing member to each other at a position overlapping, in the light emitting direction, a neutral axis of the housing or the light emitting unit or a neutral axis of the suppressing member in the light emitting direction, at plural places separated away from each other in the one direction or in a state of extending in the one direction.

There is provided an optical print head including: a substrate on which a plurality of light emitting elements is mounted on one surface, and a plurality of electronic components including a driver IC that drives the plurality of light emitting elements is mounted on the other surface opposite to the one surface; and a lens array including a plurality of lenses that respectively condenses light emitted from the plurality of light emitting elements to a photosensitive drum. The substrate includes a plurality of connecting pieces obtained by cutting a connecting portion with another substrate in a longitudinal direction of the substrate, and at least one of the connecting pieces is provided at a position corresponding to a region of the substrate where the driver IC is to be mounted in the longitudinal direction of the substrate.