An optical scanning apparatus includes a first polarizing member and a second polarizing member between a light source and a MEMS mirror that is a deflection mirror. The first polarizing member reflects a first polarization component included in a beam light emitted from the light source so as to squarely enter the MEMS mirror and passes a second polarization component having a phase difference of a half-wavelength with respect to the first polarization component. The second polarizing member is provided between the first polarizing member and the MEMS mirror to pass the first polarization component reflected by the first polarizing member therethrough twice before and after being reflected by the MEMS mirror to change the first polarization component into the second polarization component. A rotation axis of the MEMS mirror is parallel to an optical axis of the beam light immediately before being reflected by the first polarizing member.

The present disclosure provides an image-forming apparatus and a controller. The image-forming apparatus includes a photosensitive member; a scanning unit, configured to perform laser scanning on the photosensitive member at a non-constant linear speed along a main scanning direction to form an electrostatic latent image; and includes a controller, configured to make a first scanning period corresponding to a first pixel at a central region of the photosensitive member to be not equal to a second scanning period corresponding to a second pixel at a non-central region of the photosensitive member. The first pixel and the second pixel are each configured with a light-emitting time period and a non-light-emitting time period; and the light-emitting time period satisfies that a light-emitting time length of the light-emitting time period of the first pixel is same as a light-emitting time length of the light-emitting time period of the second pixel.

A laser scanning device includes a light source, a rotary polytope, a motor, a bearing, and a detection processing portion. The rotary polytope scans light emitted from the light source. The motor rotates the rotary polytope. The bearing rotatably supports a rotation shaft of the motor. The detection processing portion, in a case where the motor is driven at a first speed that is higher than a predetermined reference speed, performs detection of an abnormal state based on an atmospheric temperature detected at a position located within a predetermined first range from the bearing, and in a case where the motor is driven at a second speed that is lower than the reference speed, does not perform the detection of the abnormal state, wherein the abnormal state is a state where the temperature of the bearing has exceeded a predetermined allowable temperature.

A laser scanning device includes a light source, a rotary polytope, a motor, a bearing, and a detection processing portion. The rotary polytope scans light emitted from the light source. The motor rotates the rotary polytope. The bearing rotatably supports a rotation shaft of the motor. The detection processing portion, in a case where the motor is driven at a first speed that is higher than a predetermined reference speed, performs detection of an abnormal state based on an atmospheric temperature detected at a position located within a predetermined first range from the bearing, and in a case where the motor is driven at a second speed that is lower than the reference speed, does not perform the detection of the abnormal state, wherein the abnormal state is a state where the temperature of the bearing has exceeded a predetermined allowable temperature.

An image forming apparatus includes an image bearing member, a frame member including a support surface and made of metal, an exposure unit disposed such that an emission direction in which the light is emitted to the image bearing member is inclined with respect to the support surface, a support member made of metal and configured to support the exposure unit that is in an inclined posture with respect to the support surface, and a positioning member made of resin and configured to be in contact with the exposure unit and position the exposure unit. The support surface of the frame member is in contact with at least one of the support member or the positioning member, and wherein the exposure unit is configured to be attached to the frame member via the support member and the positioning member.

A rotating polygonal mirror has deflection faces for deflecting a light beam. A motor drives the polygonal mirror. A first detection unit outputs a first signal by detecting a light beam. A second detection unit outputs a second signal whose period is different from a period of the first signal, by detecting magnetic flux change. A specifying unit obtains a phase relationship between the first signal and the second signal, and specifies a deflection face. A storage unit stores setting information for setting whether to use rising or falling of the second signal to specify the phase relationship. The specifying unit determines whether to use rising or falling of the second signal in order to obtain the phase relationship.

An image forming apparatus includes an acquiring unit configured to acquire atmosphere pressure in the installation place of the image forming apparatus, photoconductors, light sources configured to radiate laser light, and a polygon mirror configured to be rotatable. The polygon mirror exposes the photoconductors by reflecting the laser light toward the photoconductors while rotating. The image forming apparatus further includes a control device configured to control rotation of the polygon mirror. The control device outputs an enable signal for allowing the image forming apparatus to perform printing, if rotation of the polygon mirror is stabilized after start of the rotation, and advances the timing of outputting the enable signal as the atmosphere pressure increases.

An image forming apparatus includes an image bearing member, a frame member including a support surface and made of metal, an exposure unit disposed such that an emission direction in which the light is emitted to the image bearing member is inclined with respect to the support surface, a support member made of metal and configured to support the exposure unit that is in an inclined posture with respect to the support surface, and a positioning member made of resin and configured to be in contact with the exposure unit and position the exposure unit. The support surface of the frame member is in contact with at least one of the support member or the positioning member, and wherein the exposure unit is configured to be attached to the frame member via the support member and the positioning member.

An image forming apparatus includes an acquiring unit configured to acquire atmosphere pressure in the installation place of the image forming apparatus, photoconductors, light sources configured to radiate laser light, and a polygon mirror configured to be rotatable. The polygon mirror exposes the photoconductors by reflecting the laser light toward the photoconductors while rotating. The image forming apparatus further includes a control device configured to control rotation of the polygon mirror. The control device outputs an enable signal for allowing the image forming apparatus to perform printing, if rotation of the polygon mirror is stabilized after start of the rotation, and advances the timing of outputting the enable signal as the atmosphere pressure increases.

A rotating polygonal mirror has deflection faces for deflecting a light beam. A motor drives the polygonal mirror. A first detection unit outputs a first signal by detecting a light beam. A second detection unit outputs a second signal whose period is different from a period of the first signal, by detecting magnetic flux change. A specifying unit obtains a phase relationship between the first signal and the second signal, and specifies a deflection face. A storage unit stores setting information for setting whether to use rising or falling of the second signal to specify the phase relationship. The specifying unit determines whether to use rising or falling of the second signal in order to obtain the phase relationship.