An image forming apparatus comprises: an image processor to convert image data based on a conversion condition; an image forming unit to form an image based on the converted image data using a replaceable member; a memory to store the image data and the converted image data; a sensor to perform measurement on a test image; and a controller. If the replacement of the replaceable member is detected while forming images, the controller controls the image forming unit to form the test image and generates the conversion condition based on a result of the measurement on the test image. If the replacement of the replaceable member is detected while forming the images, the controller further controls the image processor to convert the image data stored in the memory based on the generated conversion condition.

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.

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 image forming apparatus includes an exposure unit that reflects a laser beam emitted from a light source by a polygon mirror having a plurality of reflection surfaces to form a latent image on a photosensitive member, and a control unit that controls the image forming apparatus in a plurality of operation modes including a normal mode and a low speed mode having a slower process speed than the normal mode. The control unit controls the polygon mirror to use all of the plurality of reflection surfaces to reflect the laser beam when in the normal mode. When in the low speed mode, the control unit makes the process speed faster than 0.5 times that of the normal mode, rotates the polygon mirror faster than in the normal mode, and controls the polygon mirror to use only some of the plurality of reflection surfaces to reflect the laser beam.

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.

An optical scanning device includes: a light source; a light source driver that provides the light source with a drive current, on which a bias current that fluctuates according to temperature change is superimposed, for emitting light from the light source; and a bias current adjuster that provides the light source driver with a bias control signal for adjusting a magnitude of the bias current, wherein the bias current adjuster includes a current value adjusting member that is capable of changing the magnitude of the bias control signal according to temperature change, and wherein the bias control signal that has automatically changed according to temperature change of the current value adjusting member is provided to the light source driver, so that the light source driver makes the magnitude of the bias current to be superimposed fluctuate, based on the provided bias control signal.

An image forming apparatus includes an image bearing member, a transfer member, an acquiring portion, an applying portion, and a controller. When a transfer voltage is subjected to constant-voltage control so that the transfer voltage applied to the transfer member by the applying portion is substantially constant, in a case that the transfer voltage when a toner amount used for a toner image is a first toner amount is a first voltage, the controller controls the applying portion so that the transfer voltage is a second voltage smaller in absolute value than the first voltage in a case that the toner amount is a second toner amount larger than the first toner amount. The acquiring portion acquires toner amount information on the toner amount for each toner image transferred onto a single recording material.

An image forming apparatus includes: an image forming unit configured to form an image on a sheet based on an image forming condition; an image reader configured to read an image for adjustment of the image forming condition, which is formed on the sheet; and a controller configured to: control, in a case of a job for which printing of the image for adjustment is set, the image forming unit to form the image for adjustment on the sheet, and generate a correction value for the image forming condition based on a reading result of the image for adjustment, which has been obtained by the image reader, to thereby adjust the image forming condition based on the correction value.

A integrated light source module includes a planar optical waveguides layer having N light incident ports aligned with respect to each other, M light exit ports aligned with respect to each other, and optical waveguides connected to the N light incident ports and the M light exit ports, and N optical semiconductor devices facing each of the N light incident ports arranged so that light emitted from each of the N optical semiconductor devices can be incident on each of the N light incident ports, wherein light emitted from the M light exit ports can be applied to an object to be irradiated.

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.