A print head includes: a mounting board; a light source portion that includes a plurality of light emitting elements provided on one surface of the mounting board; a drive member that is provided on other surface of the mounting board so as to generate a lighting signal and drive the light source portion; and a first temperature detector that is provided on the mounting board, and at least one second temperature detector that is provided at a farther position on the mounting board from the drive member than the first temperature detector; and the drive member includes: a light emitting unit that generates the lighting signal based on a temperature detected by the first temperature detector and a temperature detected by the second temperature detector; and an optical unit that forms an image of light emitted from the light emitting unit.

An optical scanning device includes a rotary polygon mirror, a plurality of light sources, a light detecting portion, an obtainment processing portion, an a switching processing portion. The rotary polygon mirror has a reflection surface that reflects incident light, and scans, in a scanning cycle, the light reflected on the reflection surface. The light sources emit, toward the reflection surface, a plurality of light beams. The light detecting portion detects a light amount of each light beam reflected on the reflection surface. The obtainment processing portion obtains a switching timing to switch a light emission amount of each of the light sources in the scanning cycle, based on light amounts of the light beams detected by the light detecting portion. The switching processing portion switches the light emission amount of each of the light sources based on the switching timing obtained by the obtainment processing portion.

A data storage device is disclosed comprising a first head actuated over a first disk surface, wherein the first head comprises a laser configured to heat the first disk surface while writing data to the first disk surface. A write power is applied to the laser when executing a first write operation, and the first write operation is paused when a transient increase in the output power of the laser is detected. In another embodiment, a write-verify of the written data is executed when a transient decrease in the output power of the laser is detected.

An image forming apparatus can include a print head, a detector, a controller, and a power source. The print head includes one or more light emitting element rows, each light emitting element row composed of a plurality of light emitting elements. The detector detects the number of light emitting elements that emit light according to image data. The controller controls a driving voltage for driving the light emitting element based on a detection result. The power source supplies the driving voltage to the print head.

An image forming apparatus includes a plurality of light emitting elements, a detector, a controller, and an image forming unit. The light emitting elements are arranged in at least one row. The detector is configured to detect a number of light emitting elements that emit light according to image data. The controller is configured to control a driving voltage for driving the light emitting elements based on the number of light emitting elements detected. The image forming unit is configured to form an image based on light emission of the light emitting elements according to the image data.

An image forming apparatus includes a plurality of light emitting elements, a detector, a controller, and an image forming unit. The light emitting elements are arranged in at least one row. The detector is configured to detect a number of light emitting elements that emit light according to image data. The controller is configured to control a driving voltage for driving the light emitting elements based on the number of light emitting elements detected. The image forming unit is configured to form an image based on light emission of the light emitting elements according to the image data.

An image forming apparatus can include a print head, a detector, a controller, and a power source. The print head includes one or more light emitting element rows, each light emitting element row composed of a plurality of light emitting elements. The detector detects the number of light emitting elements that emit light according to image data. The controller controls a driving voltage for driving the light emitting element based on a detection result. The power source supplies the driving voltage to the print head.

In one example, a calibration of a print engine may include producing an image by scanning imaging elements along a scan direction, the image having a calibration portion that is continuous or unbroken in a direction perpendicular to the scan direction. Information indicative of an optical measurement of the calibration portion is received. A contribution to the optical measurement associated with each of the laser elements in the group of laser elements is determined. A calibration adjustment for the laser elements in the group of laser elements is determined.

A method of controlling a laser unit in order to negate heat build-up caused by a laser modulation current, and eliminating artifacts caused by image related thermal effects. Upon receipt of an activation signal, an activation current is applied which causes lasing of the laser unit. Upon receipt of a deactivation signal, the method ceases lasing by selectively applying either an idle current below the activation current, or a cooling current below the idle current.

A method of controlling a laser unit in order to negate heat build-up caused by a laser modulation current, and eliminating artifacts caused by image related thermal effects. Upon receipt of an activation signal, an activation current is applied which causes lasing of the laser unit. Upon receipt of a deactivation signal, the method ceases lasing by selectively applying either an idle current below the activation current, or a cooling current below the idle current.