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.

An image forming apparatus includes a laser device, a sensor, and a control unit. The laser device emits laser light which is reference for image forming. The sensor detects the laser light emitted from the laser device. The control unit changes an output direction of the laser light emitted from the laser device if the laser light is not detected by the sensor .

An image forming apparatus includes a laser device, a sensor, and a control unit. The laser device emits laser light which is reference for image forming. The sensor detects the laser light emitted from the laser device. The control unit changes an output direction of the laser light emitted from the laser device if the laser light is not detected by the sensor.

A scanner includes: an acquiring unit that acquires determination result information based on a determination result of whether a target dot of a target pixel of a plurality of pixels constituting image data is a first dot or a second dot; a light source control unit that, if the target dot is the first dot, causes a light source to emit a light beam during a corrected lighting time with a light source characteristic time based on a characteristic of the light source being added to a predetermined lighting time that is preliminarily determined with respect to the target dot, and if the target dot is the second dot, causes the light source to emit a light beam during the predetermined lighting time; and a deflecting unit that deflects the light beam in the main scanning direction.

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.

An image forming apparatus includes: a correction unit configured to correct a tone of each pixel in first image data in accordance with an image height on a photosensitive member, and output second image data; a halftone processing unit configured to determine exposed regions of pixels in an image by applying halftone processing to the second image data; and a scanning unit configured to form a latent image by scanning the photosensitive member with light that changes in scanning speed in accordance with an image height based on the exposed regions of the pixels. The scanning unit is further configured to perform partial exposure with respect to the pixels based on the exposed regions of the pixels, the partial exposure exposing partial regions of the pixels to light unlike entire exposure that exposes entire regions of the pixels to light.

A setting unit of a controller mounted on a control board sets a first mode for generating, from image data, PWM data indicating a pattern for causing an LD to emit light and transmitting to a laser driving board, or a second mode for transmitting to the laser driving board image data prior to generation of the PWM data. A data conversion unit, in the first mode, converts inputted image data into N pieces of PWM data respectively corresponding to N LDs, and in the second mode, converts inputted image data into image data for each scanning line. A P/S conversion unit converts data outputted from the data conversion unit from a serial format into a parallel format, and transmits the converted data to the laser driving board as control data.

A semiconductor laser driver and an image forming apparatus incorporating the semiconductor laser driver. The semiconductor laser driver includes a light source including a plurality of laser-beam source units disposed in a sub-scanning direction that serves as a group direction, the laser-beam source units having a plurality of groups arranged in a main scanning direction, each of the laser-beam source units emitting a laser beam of a light quantity dependent upon a driving current, a shading corrector to correct, according to at least one shading correction value, the driving current given to the laser-beam source units for each of the groups, and a light quantity adjuster to adjust the driving current according to a light-quantity adjustment value for the laser-beam source units. The image forming apparatus includes a semiconductor laser drive circuit, and the semiconductor laser driver that serves as the semiconductor laser driver.

An image forming apparatus comprising: an exposing unit including: a first light source comprising a first light emitter and a first light receiver including a first electric output responsive to a received light quantity of the first light emitter; a second light source comprising a second light emitter and a second light receiver including a second electric output responsive to a received light quantity of the second light emitter; and a first light-source driver electrically connected to the first light source and the second light source. The first light-source driver includes: a first output terminal electrically connected to the first light emitter; a second output terminal electrically connected to the second light emitter; and an input terminal electrically connected to both the first electric output and the second electric output.

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.