An image forming apparatus includes: a light source that emits a laser beam; a polygon mirror that reflects the laser beam; a photoreceptor that is to be exposed to the laser beam reflected by the polygon mirror; a motor that rotates the polygon mirror; and a hardware processor capable of detecting sheet type, that is, type of a sheet conveyed in the image forming apparatus, wherein the hardware processor controls to rotate the motor at a first rotation speed until the sheet type is detected, and rotate the motor at a second rotation speed determined on the basis of the sheet type after detection of the sheet type.

An image recording device includes a laser irradiation device that emits laser lights output from a plurality of laser light emitting elements to different positions in a predetermined direction; and an image recording unit that controls the laser irradiation device to irradiate a recording object moving relative to the laser irradiation device in a direction different from the predetermined direction with laser so as to heat the object, form image dots, and record an image. The image recording unit controls the laser irradiation device, conducts recording such that at least one of the image dots, recorded alongside at different positions in a direction perpendicular to a relative moving direction of the object, is shifted relative to other ones of the image dots in the relative moving direction, and records a solid image on the object such that the image dot is partially overlapped with all adjacent image dots.

In an optical scanning device, a housing has a structure divided into an upper stage and a lower stage by a mounting plate on which a deflector, a first optical system and a second optical system are mounted. A first optical system reflection mirror and a second optical system reflection mirror are mounted in the other of the upper stage and the lower stage in which the deflector is not mounted. Each of the first optical system and the second optical system is disposed across a region including the upper stage and the lower stage. The first optical system reflection mirror and the second optical system reflection mirror are disposed with the deflector located therebetween. The first optical system reflection mirror is disposed on a side of the second optical system, and the second optical system reflection mirror is disposed on a side of the first optical system.

An example laser assembly for a laser printer may include a plurality of lasers to emit respective photons; a prism to redirect the respective laser beams emitted from the plurality of lasers toward a collimator lens of the laser printer to generate a photon beam; and one or more processors to: determine a timing schedule for individually activating the plurality of lasers based on a resolution setting of the laser printer, and when printing at a resolution corresponding to the resolution setting, control activation of each of the plurality of lasers to emit the respective photons according to the timing schedule to form the photon beam.

An optical scanning apparatus includes a deflector configured to deflect a light beam from a light source and scan a surface to be scanned in a main-scanning direction and a single imaging optical element configured to guide the light beam deflected by the deflector to the surface to be scanned. Scanning speeds of the light beam on the surface to be scanned at an on-axis image height and at an off-axis image height are different from each other, and conditions
0.0<(R1.sub.h/2+R2.sub.h/2)/(R1.sub.h/2R2.sub.h/2)<1.7 and
0.8<h/TC<2.0
are satisfied.

A scanning path of light includes a synchronization detection area A where a synchronization detection sensor 47 detects scanning light and an image writing area B where writing of the image data to a photosensitive drum 11 is performed by the scanning light, and a light amount change unit 100 is configured to reduce a change amount of a light amount in the synchronization detection area A as compared with the image writing area B.

A scanning path of light includes a synchronization detection area A where a synchronization detection sensor 47 detects scanning light and an image writing area B where writing of the image data to a photosensitive drum 11 is performed by the scanning light, and a light amount change unit 100 is configured to reduce a change amount of a light amount in the synchronization detection area A as compared with the image writing area B.

An image forming apparatus includes: a speed setting portion configured to set a rotation speed of a drive motor to one of a plurality of predetermined specific speeds; a measurement processing portion configured to, in each of a plurality of detection cycles in which light is detected after scanning by a polygon mirror, measure an interval between a detection timing of the light and an output timing at which a drive signal input to the drive motor of the polygon mirror first after the detection timing, is output; and an identification processing portion configured to identify a reference reflection surface that corresponds to a reference interval, based on the measured interval and the reference interval corresponding to a specific speed at a time when the measured interval was measured, the reference interval being among reference intervals that have been set in advance for each of the specific speeds.

An image forming apparatus includes a photosensitive member and a scanning unit including a light source, a rotatable polygonal mirror, and a sensor. The image forming apparatus includes setting of an operation in a first mode and setting of an operation in a second mode. The image forming apparatus further comprises, a surface identifying portion and a correction data storing portion configured to prestore correction data including first correction data for a first rotational speed and second correction data for a second rotational speed. Positional deviation in a main scan direction of laser light is corrected on the basis of the first correction data or the second correction data.

A label modification unit may receive a label modification input that indicates a label modification associated with content being written to a label or erased from the label. The label modification unit may identify an area of the label that is associated with the label modification according to the label modification input. The label modification unit may determine, based on a size of the area, a spot size of a light beam that is configured to be emitted by a laser printhead to modify the content within the area. The label modification unit may determine, based on the spot size and the content, an optical path configuration for the laser printhead. The label modification unit may operate the laser printhead according to the optical path configuration to write the content to the area or erase the content from the area.