A light-emitting device includes a base that extends in one direction; a light-emitting unit in which multiple light sources that are disposed in the one direction are supported by a supporting body that extends in the one direction and that is formed from a metal block; a spacer that is interposed between the base and the light-emitting unit in a direction of an optical axis of each light source; and a fixing unit that fixes the light-emitting unit to the base in a mode in which a compressive load is applied to the spacer.

A drive circuit that includes a switching circuit switching between a first state and a second state to cause a light-emitting element to perform pulse oscillation, and a direct current adjustment circuit. In the first state, light is emitted from a light-emitting element by supplying the light-emitting element with a current having a magnitude equal to or greater than a threshold current enabling the light-emitting element to emit light having an output equal to or greater than a predetermined output. In the second state, the magnitude of the current supplied to the light-emitting element is less than the threshold current. The direct current adjustment circuit supplies, to the light-emitting element, a bias current within a range less than the threshold current of the light-emitting element in the second state. The bias current has a magnitude corresponding to a magnitude of undershoot occurring at a falling edge of the pulse oscillation.

An image forming apparatus to form a toner image on a recording material includes a photosensitive member and an optical scanning unit. The optical scanning unit includes an optical scanning unit, an optical box, a cover member, and a moving unit movable to an outside of the image forming apparatus. The optical scanning unit and the moving unit are arranged so that the moving unit and the optical scanning unit are opposed to each other when the moving unit is located in an inside of the image forming apparatus. The optical scanning unit is disposed so as to allow a user to touch the optical scanning unit through a space generated in the inside of the image forming apparatus when the moving unit is moved to the outside of the image forming apparatus. Between the optical box and the cover member, the cover member is opposed to the moving unit.

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.

An image forming apparatus includes a plurality of photosensitive members; a scanner unit including light sources, a rotatable polygonal mirror, and reflecting members; and a fixing portion. Parts of the laser beams emitted from the light sources are reflected by the rotatable polygonal mirror toward the fixing device side, and rest parts of the laser beams are reflected by the rotatable polygonal mirror toward a side opposite from the fixing device side. Of the parts of the laser beams reflected by the rotatable polygonal mirror toward the fixing device side, the laser beam reflected toward the reflecting member provided at a position remotest from the rotatable polygonal mirror travels downward relative to a horizontal direction. A rotational axis of the rotatable polygonal mirror is inclined relative to a vertical direction.

An image forming apparatus includes first and second light sensors positioned in a laser scanning system of at least one color, such that scanned light is detected by the first light sensor and then by the second light sensor and light sensing surfaces of the first and second light sensors are not parallel, and a control unit connected to the first and second light sensors and configured to determine a time difference in the timing of light detection by the first and second light sensors and to execute a color position shift operation upon determining that the time difference is greater than a first threshold value.

An optical scanning device includes a light source, a deflector, a random number generator, a selection part, a random number assignment part and an exposure control part. The light source includes a plurality of light emitting parts arranged in a predetermined direction at fixed intervals in a sub-scanning direction. The random number assignment part is configured to assign a random number sequence to each light emitting part constituting a set of target light emitting parts as an index for specifying a timing at which a light emitting time of the set of target light emitting parts is set to a correction value different from a reference value and to update the assignment of the random number sequence at a random number update period. The random number update period coincides with a scanning period of each light emitting part constituting the set of target light emitting parts.

An image forming device includes an LED head, a main controller board and an LED controller board. The main controller board comprises a main controller, a voltage output circuit, a first voltage terminal, a second voltage terminal. The voltage output circuit outputs a first voltage via the first voltage terminal and the second voltage via the second voltage terminal. The LED controller board comprises a third voltage terminal, a fourth voltage terminal and an LED controller. The third voltage terminal is connected to the first voltage terminal, and the fourth voltage terminal is connected to the second voltage terminal. The LED controller board outputs a voltage according to the first voltage to the LED head. The LED controller is connected to the fourth voltage terminal. A voltage according to the second voltage is input to the LED controller.

A controller which causes a light emitting element to continuously perform minute emission for a plurality of dots in a level in which toner is not attached to a non-image section on an image bearing member is provided. The controller controls a first driving current for an image section and controls a second driving current used to perform the minute emission by the light emitting element in the non-image section several times in one job. In the image section, a driving current obtained by adding the first driving current to the second driving current is supplied so that the light emitting element emits light.

An optical member that refracts a light beam to diverge or focus the light beam, includes: at least three pairs of opposing surfaces. Each of the three pairs of opposing surfaces include a lens. Curvatures of the lenses at one side surfaces of the respective three pairs of surfaces are all the same, or curvatures of the lenses at one side surfaces of respective pairs of at least two pairs of the three pairs of surfaces are different from each other, and respective shortest distances between optical axes of the lenses at the one side surfaces of respective pairs of the at least two pairs of surfaces, and reference sides which are each any one of respective sides surrounding surfaces including the lenses are different from each other.