An image forming apparatus including: a light source configured to emit a light beam; a rotary polygon mirror including a plurality of reflection surfaces each configured to deflect the light beam emitted by the light source so that the light beam scans a surface of a photosensitive member; a light receiving portion configured to output a light receiving signal by receiving the light beam reflected by each of the plurality of reflection surfaces; a conversion unit configured to convert the light receiving signal to a pulse signal; a measurement unit configured to measure pulse widths of a plurality of pulse signals corresponding to the plurality of reflection surfaces, respectively; and an identification unit configured to identify a rotation phase of the rotary polygon mirror based on a measurement result of the measurement unit and reference values to be compared with the measurement result.

An optical writing device, and a method of controlling the optical writing device. The optical writing device and the method includes controlling speed of operation of a light deflector based on image magnifying-power information in a sub-scanning direction parallel to a direction in which a surface of a photoconductor moves, and controlling a prescribed write clock frequency such that a number of clock pulses of write light will become a target number of pulses over a period where the write light scans an area within a prescribed distance in a main scanning direction, the target number of pulses being maintained even when the speed of operation of the light deflector is changed in the controlling the speed of operation of the light deflector. The write clock frequency controller maintains the target number of pulses even when the speed of operation of the light deflector is changed by the light-deflector controller.

A laser printing system includes a laser configured to produce a beam of light modulated according to image data input to the laser printing system, a photoreceptor drum including a photoconductive layer disposed along an outer peripheral surface of the photoreceptor drum, and a non-mechanical beam steerer configured for receiving the modulated light beam from the laser and steering the light beam in a scanning motion back and forth across the photoconductive layer of the photoreceptor drum. The laser printing system also includes a printer controller configured to structure the image data input to the laser printing system, and control an amount of electrical current flowing through portions of the non-mechanical beam steerer to change an effective index of refraction of the non-mechanical beam steerer and steer the modulated light beam in the scanning motion.

An optical scanning apparatus includes: a casing having a bottom face; a cylindrical portion having a first opening through which a laser beam from a light source passes; a light-transmitting member arranged between the cylindrical portion and a rotary polygon mirror; a plate spring fixing the light-transmitting member; and a sealing member between the cylindrical portion and the plate spring, wherein a width of the first opening narrows progressively in a insertion direction of the plate spring, the sealing member comes into contact with the cylindrical portion in a first region when the plate spring is inserted, and in a second region closer to the bottom face than the first region, a region, in which the sealing member comes into contact with the cylindrical portion, expands toward a center part from two end portions of a leading end portion of the sealing member as the plate spring is inserted further.

An image forming apparatus including a polygon mirror that deflects a light beam, the image forming apparatus includes: an optical sensor arranged such that the light beam deflected by the polygon mirror enters the optical sensor; and a hardware processor that measures an output level of the optical sensor and calculates, as a remaining life of the polygon mirror, an operation time of the polygon mirror to when the output level becomes a threshold value in a case of assuming that the output level ongoingly changes at a rate of change over time that is a change amount of the output level per unit operation time of the polygon mirror, using the measured output level.

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 scanning device includes a casing (31). The casing (31) can be stacked in a plurality of stages in a state in which a lid member (32) has been removed, and includes a connection leg part (31e) extending from a predetermined position of the outside surface of a sidewall part (31b) to a lower side of a lower surface of the casing (31), and the connection leg part (31e) is provided with an engaged part (31g) for connection which is engaged with an engaging part (31d) formed at a sidewall part (31b) of another casing (31) when the casing (31) is stacked on an upper side of the other casing (31).

A laser scanning device for marking objects includes an optical port configured and arranged to receive a laser beam; a lens configured and arranged to focus the laser beam to modify a surface of a material to be marked; and an electrically controlled linear actuator coupled with the lens. The electrically controlled linear actuator is configured to move the lens linearly, thereby causing the laser beam to scan across the surface of the material to be marked as a result of changes in a refraction angle, of the laser beam passing through the lens, caused by the linear movement.

Disclosed is a method of adjusting a plurality of optical elements associated with a printing system ROS. According to one exemplary embodiment, sensitivity analysis is performed on a computer model of the ROS system and an optical element alignment sequence is generated to minimize the number of optical element adjustments needed to achieve a predefined ROS performance.

An image forming apparatus includes a light scanning device, a light detection unit, and a positional-deviation-amount calculation unit. The light detection unit includes a slit-shaped first light detection region and a slit-shaped second light detection region arranged to have mutually different angles with respect to a scanning direction of the light beam, and outputs a detection signal when the light beam passes through each of the light detection regions. The positional-deviation-amount calculation unit calculates a time period until when the light beam passes through the second light detection region from when the light beam has passed through the first light detection region for each scan of the light beam based on the detection signal output from the light detection unit, and calculates a variation characteristic of a positional deviation amount in a sub-scanning direction of the light beam associated with rotation of the polygon mirror.