In a housing, an installation surface (44g) of an image forming lens unit (42L) is formed at a higher position by a level difference than an installation surface (44f) of a polygon motor (41), and when viewed from a rotation axis direction of a polygon mirror unit (40), a diameter (r) of a circumscribed circle passing each apex of the polygon mirror unit (40) is larger than an outer diameter (R) of a rotor part (41a) of the polygon motor (41).

A brushless motor device configured to: determine a first upper limit of a current value which flows through a coil when a rotation speed of a rotor is accelerated from a first speed to a second speed, wherein, in a case where the current value of the first upper limit flows through the coil when the rotor is rotated at the second speed, a first time period, which is from a start of a non-energization time period of the coil until an induced voltage reaches a threshold value, is longer than a second time period, which is from the start of the non-energization time period until a counter-electromotive voltage becomes zero; and change switching of each switching element of an inverter circuit by using a second upper limit greater than the first upper limit and the first upper limit.

An image forming apparatus includes: a speed setting portion configured to set a rotation speed of a drive motor to one of a plurality of predetermined specific speeds; a measurement processing portion configured to, in each of a plurality of detection cycles in which light is detected after scanning by a polygon mirror, measure an interval between a detection timing of the light and an output timing at which a drive signal input to the drive motor of the polygon mirror first after the detection timing, is output; and an identification processing portion configured to identify a reference reflection surface that corresponds to a reference interval, based on the measured interval and the reference interval corresponding to a specific speed at a time when the measured interval was measured, the reference interval being among reference intervals that have been set in advance for each of the specific speeds.

Method of controlling a laser marking matrix system, the matrix system comprising an NM matrix of lasers to produce the laser marking, the method comprising the sequential transformation of at least two images to be marked into a series of marking commands according to an NM matrix of dots, which comprises the following phases: division of a first image into a fixed portion and a variable portion, transformation of the fixed portion into a fixed matrix and the variable portion into a variable matrix, combination of said fixed and variable matrices, laser marking of the first image, processing of a second image, obtaining a new variable matrix which is added to the previous fixed matrix, producing a complete new matrix, laser marking of the second image.

In an optical scanning device including a vibration mirror part, elastically deformable resin portions are respectively provided at both end portions in a main scanning direction on a surface of the vibration mirror part, which is an opposite surface of a reflective surface, a collision member, which has a collision surface and can collide with each of the resin portion, is provided at a side opposite to a side of the reflective surface of the vibration mirror part, and a control unit allows the vibration mirror part to swing such that each of the resin portion collides with the collision surface at least once before light beam for image data writing is deflected and scanned by the vibration mirror part, and then allows the vibration mirror part to swing in a range in which each of the resin portion does not collide with the collision surface.

A laser manufacturing system including a spatial light modulator (SLM) with a rectangular array of electrically actuated two-dimensional (2D) diffractors arranged to form multiple pixels spaced linearly along a long-axis thereof, each pixel including a plurality of 2D diffractors electrically ganged together and arranged along a short-axis perpendicular to the long-axis. The system further includes a laser and optics to illuminate the SLM, and projection optics to project modulated light from the SLM onto a surface of a workpiece to form an anamorphic image of the SLM that is demagnified along the long-axis of the SLM and tightly focused along the short-axis to form a condensed line beam to mark the workpiece. The line beam has a sinc.sup.2 profile along the short-axis and a top-hat along the long-axis. Demagnification and the resulting long-axis length at the workpiece is chosen based on the pulse-energy of the laser and targeted peak fluence.

An image forming apparatus includes a unit configured to perform image forming operation, a unit board in the unit, a wiring configured to be connected to the unit board, and a control board configured to be connected to the unit board with the wiring and control the unit. The unit board includes a connector to which the wiring is to be connected. A length of the connector in a longitudinal direction of the connector is longer than a length of the unit board in a widthwise direction of the unit board, and the longitudinal direction of the connector intersects the widthwise direction of the unit board.

A light beam scanning device scans a luminous flux irradiated from a light source and deflected by a deflector to a scanned surface through an optical system having a set of mirrors. A apparatus, such as the light beam scanning device, further includes a scanning line curve adjusting device to bend a first mirror of the set of mirrors so as to correct a curve in a scanning line on the scanned surface, and a scanning line tilt adjusting device to change orientation of a second mirror of the set of mirrors so as to correct a tilt in the scanning line on the scanned surface. The light beam scanning device may be provided in an image forming apparatus.

A scanning path of light includes a synchronization detection area A where a synchronization detection sensor 47 detects scanning light and an image writing area B where writing of the image data to a photosensitive drum 11 is performed by the scanning light, and a light amount change unit 100 is configured to reduce a change amount of a light amount in the synchronization detection area A as compared with the image writing area B.

A light scanning apparatus includes a laser light source, an anamorphic element converging a laser beam from the laser light source in a sub-scan direction, a deflector deflecting and scanning the laser beam, an image-forming optical system converging the deflected laser beam in a scan direction onto a scan target surface, and a reflective member between the image-forming optical system and the scan target surface to reflect the laser beam onto the scan target surface. When an F value of axial beam in the scan direction is Fno, an F value of beam at a maximum image height in the scan direction is Fno, and an incidence angle of beam at the maximum image height onto the scan target surface in the scan direction is , the following Equation (1) is satisfied:

{1-(1-cos .sup.4)/M}/cos .sup.4Fno.sup.2/Fno.sup.21/cos .sup.4 (1) where M is an arbitrary real number that is 2 or greater and 2 or smaller.