An image forming apparatus includes an image forming section, an optical scanning device, an image density sensor, and a control unit. The optical scanning device scans the surface of the image carrying member with light emitted from light sources to form an electrostatic latent image. The control unit can perform light amount calibration to adjust the exposure amount of the light scanning device based on the density of a reference image detected by the image density sensor. The reference image used for light amount calibration has a dot pattern in which as many individual dots as there are light sources are arrayed at regular intervals in the main scanning direction. The dot pattern is formed repeatedly in the main and sub scanning directions. The dots forming the dot pattern are arranged at different positions in the sub scanning direction to be displaced in units of pixels from each other.

An optical scanning device includes a housing, a transmissive member, a linear member, a drive portion, a guide rail, a cleaning holder, a cleaning member, a detection portion, and a control portion. The detection portion includes a light emitter that emits light in a juxtaposition direction of the transmissive member and a light receiver that receives the light emitted from the light emitter. The cleaning holder includes a light blocking portion that is located, when the cleaning holder reaches one end part of a movement path thereof, between the light emitter and the light receiver so as to block the light emitted from the light emitter, with a gap formed between the light blocking portion and the housing. The housing includes a light leakage prevention portion formed between the light emitter and the light receiver.

An image forming apparatus includes a photosensitive member, an exposing unit scanning the photosensitive member with a laser, a generating unit generating a clock signal, a first correcting unit correcting a frequency of the clock signal for each position in a main scanning direction, a developing unit, a driving unit, a second correcting unit correcting an image date by a correction coefficient depending on the position in the main scanning direction, and a modulating unit modulating the image date corrected by the second correcting unit into the driving signal. The correction coefficient increases as it goes toward an end from a center in the main scanning direction and includes an inflection point where an inclination, which is an increase amount of the correction coefficient to a unit increase amount of the position, is changed. The inflection point is positioned near the end in the main scanning direction.

A scanning optical device includes a polygon mirror to deflect and scan a luminous flux emitted from a light source, an imaging lens and an optical box. The imaging lens is long in a scanning direction of the polygon mirror. The optical box is provided with the polygon mirror and the imaging lens. The optical box includes two positioning portions to position one end and the other end of the imaging lens in the scanning direction. In a position adjacent to one positioning portion of the two positioning portions in the scanning direction and on a side of the other positioning portion, an inclined surface is provided. The inclined surface extends in a direction from the one positioning portion toward the other positioning portion and inclines so as to lower in height as it goes to the other positioning portion from the one positioning portion.

An image forming apparatus includes an apparatus body having an opening portion, an opening/closing member, a first unit configured to be attachable to and detachable from the apparatus body via the opening portion, a second unit configured to be attachable to and detachable from the apparatus body via the opening portion, an exposure unit provided in the apparatus body, a shutter member provided in the apparatus body and configured to move to a blocking position and a non-blocking position, and an interlocking mechanism provided in the apparatus body and configured to operate in an interlocking manner with the first unit, the second unit, and the opening/closing member. The interlocking mechanism is configured to position the shutter member at the non-blocking position in a state where the first unit and the second unit are attached to the apparatus body and the opening/closing member is positioned at the closed position.

A scanning optical device includes a deflector to deflect a laser light from a lase element, a detector to output a synchronizing signal, a switch provided in a supplying path which supplies a current to the laser element and to be switched to an ON state and to an OFF state. A protection circuit to which the synchronizing signal is inputted from the detector changes an output when a predetermined time depending on a time constant there of elapses, and of which the output is connected to the switch. The protection circuit changes the output, in a case in which the synchronizing signal is not inputted from the detectors for the predetermined time from when the switch is switched to the ON state by a control signal, and thereby the switch is switched to the OFF state irrespective of a state of the control signal.

An image forming apparatus includes a light emitter; a photoconductor to form a latent image on a surface of the photoconductor; a deflector to deflect light at a write start timing; an optical sensor; and circuitry. The optical sensor detects the scanning light scanning, with one of multiple sensitivities. The circuitry adjusts a light intensity of the emitted light and the write start timing based on the detection signal; switches from the one of multiple sensitivities to other of multiple sensitivities or from the other of multiple sensitivities to the one of multiple sensitivities based on the light intensity adjusted; and determines whether to perform a color misregistration correction based on a shift in the write start timing caused by a switch from the one of multiple sensitivities to the other of multiple sensitivities or from the other of multiple sensitivities to the one of multiple sensitivities.

This disclosure provides an image forming apparatus that adjusts density of a virtual latent-image line by causing a laser corrector to correct a plurality of laser beams. The image forming apparatus controls an exposure section and causes a scanning region of a photoreceptor to be irradiated with the plurality of laser beams in a main-scanning direction to form a real latent-image line, determines whether or not a virtual latent-image line is formed between the two real latent-image lines adjacent to each other in a sub-scanning direction, and causes a laser corrector to correct a plurality of laser beams on the basis of the determination result to adjust density of a virtual latent-image line.

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 optical scanning device includes a casing, a transmissive member, a linear member, a drive portion, a plurality of first guide rails, a plurality of second guide rails, at least one cleaning holder, a cleaning member, and a stopper. The casing includes a rib formed along a peripheral edge part of an upper surface of the casing and a void section formed between the rib and an end part of the first guide rails on a side of the second direction. The cleaning holder includes a first restriction portion that engages with the first guide rails in an up-down direction and a second restriction portion that is in contact with a side surface of the second guide rails.