An optical writing apparatus includes: a light source panel including light emitting elements arranged on an elongate glass substrate; an optical member that causes emergent light to form an image; a first holding member holding the optical member; and a second holding member holding the glass substrate, wherein legs are provided below the first holding member on sides of both ends, the legs extending downward, drooping ends of the legs being mounted and fixed on the second holding member, one end of the glass substrate is positioned inside the space, an integrated circuit being provided, a through hole is provided to an upper surface of the second holding member, and when cooling air for the integrated circuit flows into the space, the cooling air is guided through the through hole to a side of a lower surface of the upper surface of the second holding member.

An image forming apparatus includes a photosensitive drum that rotates in a predetermined direction, an LED head that exposes the photosensitive drum, a drum contact surface that contacts against the outer peripheral surface of the photosensitive drum, and a head contact surface that contacts the LED head. Further, the image forming apparatus includes a spacer for regulating a distance between the photosensitive drum and the LED head, and a coil spring for pressing the LED head toward the spacer. The LED head has an engagement hole to engage the spacer. The spacer has a protrusion that engages with the engagement hole and regulates movement of the LED head in a predetermined direction.

An exposure unit comprises a polygon mirror configured to include a plurality of reflection surfaces; first to fourth light sources arranged at different angle positions along a rotation direction of the polygon mirror; two photo detectors configured to selectively detect first laser light and fourth laser light respectively at a scanning start end side of a main scanning direction among first to fourth laser light which are emitted from the respective light sources and reflected by the polygon mirror to be scanned in the main scanning direction; and a control section configured to control light emitting timing of the first to the fourth light sources on the basis of detection results of these photo detectors.

According to one embodiment, there is provided a light emitting substrate which includes a transparent substrate, a plurality of light emitting element groups, and a control unit. The plurality of light emitting element groups are formed by overlapping a first light emitting element and a second light emitting element on the transparent substrate. The control unit controls light emitting of the first light emitting element and the second light emitting element of the plurality of light emitting element groups. Amounts of light emitted from the plurality of light emitting element groups are uniform.

There is provided a lens mirror array and an image forming apparatus with highly accurate image formation and image obtainment, and less stray light. According to one embodiment, there is provided a lens mirror array in which a plurality of optical elements are arranged, each of the optical elements including a first lens surface on which light is incident, a first mirror surface that reflects the light incident on the first lens surface, a second mirror surface that reflects the light reflected by the first mirror surface, and a second lens surface that emits the light reflected by the second mirror surface.

There is a demand for an inexpensive optical scanning apparatus. An optical scanning apparatus includes a light source configured to emit a laser light flux, a deflection unit configured to deflect the laser light flux emitted from the light source, and a light reception member configured in such a manner that the laser light flux reflected by the deflection unit is incident thereon. The light source emits the laser light flux tilted by a predetermined angle with respect to a horizontal direction toward the deflection unit. The light reception member is disposed above or below the light source, and the laser light flux reflected by the deflection unit and tilted by the predetermined angle with respect to the horizontal direction is incident on the light reception member.

According to one embodiment, there is provided a print head including a transparent substrate, light-emitting elements, a lens, and a member. The transparent substrate includes a first surface and a second surface. The light-emitting elements are on the first surface of the transparent substrate. The lens condenses the irradiation light from the light-emitting elements that is transmitted through the first surface and the second surface, onto an object. The member is a member for preventing a part of reflected light of the irradiation light from being incident again on the incident surface of the lens.

An imaging device for projecting individually controllable laser beams onto an imaging surface movable in an X-direction. The device includes a plurality of semiconductor chips each comprising a plurality of laser beam emitting elements arranged in a main array of M.Math.N. The chips are mounted such that each pair of adjacent chips in the Y-direction are offset from one another in the X-direction and, if activated continuously, the emitted laser beams of the two chips of said pair trace on the imaging surface a set of parallel lines that are substantially uniformly spaced in the Y-direction. In addition to the M.Math.N elements of the main array, each chip comprises at least one additional column on one or each side, each additional column containing at least one selectively operable element capable of compensating for any misalignment in the Y-direction in the relative positioning of the adjacent chips on the support.

Scanning optical unit includes: light source; incident optical system including one coupling lens for converting light from the light source into a light beam; optical deflector having a reflecting surface and configured to reflect and deflect the light beam in main scanning direction; and scanning optical system for focusing the deflected light beam on an image surface. The incident optical system converges the light beam on the reflecting surface in sub-scanning direction. Further, 0.01(s/m).sup.20.27 and s2<1 are satisfied, where m is a lateral magnification of the entire optical system from the light source to the image surface in the main scanning direction, s is a lateral magnification of the entire optical system in the sub-scanning direction, and s2 is a lateral magnification of the scanning optical system from the reflecting surface of the optical deflector to the image surface in the sub-scanning direction.

An image forming apparatus obtains a number of pixels to be developed on a downstream side in a sub-scanning direction from the each one of the predetermined pixels, in order to correct a density increase that occurs at the trailing edge of an image to be formed in accordance with a peripheral speed difference between a photosensitive drum and a developing roller, determines a correction amount of light amount for each one of the predetermined pixels in accordance with the obtained number of pixels, and generates image formation data.