An optical print head that performs optical writing to a photoreceptor includes: a light transmissive substrate; a light emitting unit including light emitting element groups, each of which includes two or more light emitting elements disposed on a first main surface of the substrate; a lens array including lenses that correspond one-to-one to the light emitting element groups; light detection units disposed above the second main surface of the substrate in one-to-one correspondence to the light emitting element groups and that detects the light from each of the light emitting elements; and correction unit that corrects light amounts of the light emitting elements of the light emitting element group based on detection of the light detection units.

An image forming apparatus includes a cartridge including a photosensitive drum; an endless belt configured to transfer the toner image formed on the drum; an endless belt supporting member movable between a contacting position for contacting the belt to the drum and a non-contacting position retracted from the contacting position away from the drum; and a cartridge supporting member movable between an image forming position in which the drum contacts the belt taking the contacting position and a non-image-forming position in which the cartridge is movable from a inside to a outside of the main assembly. By movement of the belt from the contacting position to the non-contacting position, a space capable of accommodating at least a part of the cartridge supporting member taking the non-image-forming position and/or the cartridge supported by the cartridge supporting member taking the non-image-forming position is provided.

An image forming apparatus includes a cartridge including a photosensitive drum; an endless belt configured to transfer the toner image formed on the drum; an endless belt supporting member movable between a contacting position for contacting the belt to the drum and a non-contacting position retracted from the contacting position away from the drum; and a cartridge supporting member movable between an image forming position in which the drum contacts the belt taking the contacting position and a non-image-forming position in which the cartridge is movable from a inside to a outside of the main assembly. By movement of the belt from the contacting position to the non-contacting position, a space capable of accommodating at least a part of the cartridge supporting member taking the non-image-forming position and/or the cartridge supported by the cartridge supporting member taking the non-image-forming position is provided.

A light emitting device includes: a base that extends in one direction and that is formed of a metal block; plural light emitters that are disposed on a front surface side of the base so as to be displaced from each other in the one direction and in each of which plural light sources that are arranged in the one direction are supported by a support that extends in the one direction; and a protective member that is provided at an end portion of the base in a direction intersecting the one direction, that is disposed on a lateral side of the plural light emitters so as to extend in the one direction, and that protects the plural light emitters from outside.

An image projection apparatus includes a light emission unit for emitting laser light; a light scanning unit for projecting an image on a drawing area by reflecting the light and scanning the reflected light; a light detection unit arranged outside of the drawing area; a detection unit for detecting, according to a deviation from a desired value of a first pixel detected by the light detection unit when the light is horizontally scanned in a first direction and a deviation from a desired value of a second pixel detected by the light detection unit when the light is horizontally scanned in a second direction, each of a phase deviation of the laser light in a horizontal scanning direction and a swing angle fluctuation of the light scanning unit; and a compensation unit configured to compensate for each of the phase deviation and the swing angle fluctuation.

An image projection apparatus includes a light emission unit for emitting laser light; a light scanning unit for projecting an image on a drawing area by reflecting the light and scanning the reflected light; a light detection unit arranged outside of the drawing area; a detection unit for detecting, according to a deviation from a desired value of a first pixel detected by the light detection unit when the light is horizontally scanned in a first direction and a deviation from a desired value of a second pixel detected by the light detection unit when the light is horizontally scanned in a second direction, each of a phase deviation of the laser light in a horizontal scanning direction and a swing angle fluctuation of the light scanning unit; and a compensation unit configured to compensate for each of the phase deviation and the swing angle fluctuation.

A light source unit includes a light emitting substrate, a light shielding body and a lens array. The light emitting substrate includes a plurality of light emitting elements. The light shielding body blocks unnecessary light of the light emitting elements. The lens array includes a plurality of lenses. The lens array is fixed directly to the light emitting substrate in a state in which the light shielding body is positioned between the light emitting substrate and the lens array.

A casing of an optical scanning apparatus housing a rotary polygon mirror and an optical member: a mounting portion on which a sound insulation member separating the optical member from the rotary polygon mirror is mountable; a first support portion supporting a transparent member which covers an opening of the casing on which the sound insulation member is mounted; a second support portion supporting a transparent member which covers the opening of the casing on which the sound insulation member is not mounted and is thicker than the transparent member to be supported by the first support portion; and a bearing surface of the second support portion located on an inner side of the casing than a bearing surface of the first support portion so that light beam emission surfaces of the transparent members to be supported by the first and second support portions are on a substantially same plane.

A casing of an optical scanning apparatus housing a rotary polygon mirror and an optical member: a mounting portion on which a sound insulation member separating the optical member from the rotary polygon mirror is mountable; a first support portion supporting a transparent member which covers an opening of the casing on which the sound insulation member is mounted; a second support portion supporting a transparent member which covers the opening of the casing on which the sound insulation member is not mounted and is thicker than the transparent member to be supported by the first support portion; and a bearing surface of the second support portion located on an inner side of the casing than a bearing surface of the first support portion so that light beam emission surfaces of the transparent members to be supported by the first and second support portions are on a substantially same plane.

A casing of an optical scanning apparatus includes: a mounting portion to which a sound-insulating member is mountable; a first and a second support portions supporting a reflective mirror in the casing on which the sound-insulating member is mounted and brought into contact with a back surface of the reflective mirror; and a third and a fourth support portions supporting a reflective mirror in the casing on which the sound-insulating member is not mounted and brought into contact with a back surface of the reflective mirror, wherein the first and the second support portions are positioned between the third and the fourth support portions in a longitudinal direction of the reflective mirror, and contact portions of the third and the fourth support portions protrude toward a reflective surface side of the reflective mirror to be arranged with respect to contact portions of the first and the second support portions.