An image forming apparatus includes plural photosensitive members, a scanner unit for scanning the photosensitive members, and a fixing unit for fixing toner images. The scanner unit includes a rotatable polygonal mirror for reflecting laser beams emitted in correspondence to respective photosensitive members, reflecting members for reflecting the laser beams, and a box for accommodating the polygonal mirror and the reflecting members. The box includes plural outlets for the laser beams. Of the reflecting members, first and second reflecting members reflect laser beams toward corresponding first and second outlets respectively positioned farthest from and closest to the fixing unit. A distance between the first outlet and its corresponding photosensitive member is longer than a distance between the second outlet and its corresponding photosensitive member, whereas a distance between the first reflecting member and the polygonal mirror is shorter than a distance between the second reflecting member and the polygonal mirror.

The present disclosure provides an optical scanning apparatus and an electronic image-forming apparatus. The optical scanning apparatus includes a light source; a first optical unit; an optical deflector, configured to deflect the light beam emitted from the first optical unit; and a second optical unit, configured to guide the light beam deflected by the optical deflector on a scanned target surface for forming an image. An image height on the scanned target surface satisfies an expression: Y=fc×tan(B×θ), where Y denotes the image height on the scanned target surface, fc denotes an image-forming characteristic coefficient of the second optical unit, B denotes a scanning coefficient of the second optical unit, θ denotes an effective scanning angle of the optical scanning apparatus, and all region or a partial region in effective scanning range of the second optical unit satisfies a condition: 0.7≤B≤0.9.

An image forming apparatus includes a scanning means provided with a light source, a polygon mirror and a driving means for driving rotation of the polygon mirror; a photosensitive member, a developing means, and a detecting means for detecting a laser light from the light source. A controller controls to execute a light emission operation so that an area including an image forming area of the photosensitive member is irradiated with the laser light. The controller controls to execute a switching operation in which a rotational speed of the polygon mirror is switched from a first speed to a second speed different from the first speed. The controller controls to execute the light emission operation in a state in which the photosensitive member and the developing means are in contact and are rotating, and to execute the switching operation based on a detecting result of the detecting means in the light emission operation.

Focusing optics can include optical elements disposed and bonded in a linear arrangement (linear array) in at least two rows. A transparent bonding agent can secure alignment of the at least two rows of the optical elements. Scattering elements can also be disposed in the transparent polymer to cause light diffusion. Diffused or un-diffused light from a semiconductor laser array can then be caused to pass through the optical element and illuminate a target substrate such as an imaging member in a printing system.

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 forming apparatus includes a photoreceptor; an image signal generating unit configured to generate an image signal based on input image data; a light emitting portion configured to emit light based on the image signal and expose the photoreceptor; a driving unit configured to drive the light emitting portion; a first substrate in which the driving unit is provided and a plurality of the light emitting portions is provided in a direction parallel to a rotational axis direction of the photoreceptor; an exposure head including the first substrate; a reference clock signal generating unit configured to generate a reference clock signal that is a clock signal of a constant frequency; a modulated clock signal generating unit configured to generate a modulated clock signal by performing spread spectrum on the reference clock signal, the modulated clock signal being a composite wave in which odd-order harmonics are combined with a fundamental wave when a triangular wave is subjected to Fourier series expansion; a transmission unit configured to superimpose the modulated clock signal on the image signal and transmit the superimposed signal to the first substrate; a second substrate on which the image signal generating unit, the modulated clock signal generating unit, and the transmission unit are provided; and an extraction circuit that is mounted on the first substrate and extracts the modulated clock signal from the superimposed signal transmitted from the transmission unit.

An optical scanning device comprises an optical box that houses an optical component(s). The optical box includes a box main body and a cover member. A first engaging portion is formed on a side wall of the box main body, and a second engaging portion that engages with the first engaging portion is formed on a first fitting wall portion of the cover member. The box main body is provided with a vertical wall that is erected inside the first engaging portion. Moreover, there is formed on the cover member with a first barrier wall that is protruded downward from a top wall so as to enter a space between the first engaging portion and the vertical wall.

Alight scanning apparatus according to the present invention includes a deflecting unit configured to deflect a light flux to scan a scanned surface in a main scanning direction, and an imaging optical system configured to guide the light flux deflected by the deflecting unit to the scanned surface and to have different partial magnifications in the main scanning direction between an on-axis image height and an outermost off-axis image height. A ratio of a reflectivity at a first outermost off-axis deflection point on one side with respect to an on-axis deflection point on a deflecting surface of the deflecting unit to that at the on-axis deflection point, and a ratio of the reflectivity at a second outermost off-axis deflection point on the other side with respect to the on-axis deflection point on the deflecting surface to that at the on-axis deflection point are each appropriately set.

An optical scanning device includes a light source, a photodetector, an optical element group, and a polygon mirror. The light source is configured to emit laser light. The photodetector is configured to detect a beam formed with the laser light. The optical element group is configured to guide the beam to the photodetector. The polygon mirror is configured to perform deflection scanning on the beam, which deflects the beam from a first end in one direction of a main scanning direction to a second end on a side opposite to the first end of the main scanning direction. The beam is incident on the same side of the photodetector when the beam is deflected toward the first end and the second end by the polygon mirror.

A light scanning unit includes a plurality of light source portions to emit modulated light beams intermittently according to image information of an image forming job while the image forming job is performed, and a plurality of polygonal mirrors, having different numbers of deflection facets, to rotate at a same rotational speed while is image forming job is performed so that the modulated light beams are incident on a subset including at least one of the deflection facets of the plurality of polygonal mirrors that rotate and the subset including the at least one of the deflection facets deflects the modulated light beams incident thereon to scan an object to be exposed.