An image forming apparatus includes: a photosensitive member; a process member configured to act on the photosensitive member; and a light scanning apparatus configured to emit a light beam to the photosensitive member. The light scanning apparatus includes: a light source; a rotary polygon mirror; a first signal generating unit configured to receive the light beam deflected by the rotary polygon mirror to generate a first signal indicating a scan starting position; and a second signal generating unit configured to generate a second signal based on a rotation angle of the rotary polygon mirror. A lighting-up timing of the light source for generating the first signal is determined based on a number of the second signals after a voltage for image formation is applied and a relationship between the first signal and the second signal is obtained before the voltage is applied and after the rotary polygon mirror is rotated.

Scanning optical system, comprising a rotatable mirror unit including first and second mirror surfaces each inclining relative to a rotation axis, and a light projecting system including a light source which emits light flux toward an object through the mirror unit. The light flux is reflected on the first mirror surface, then to the second mirror surface, and projected so as to scan on the object correspondingly to rotation of the mirror unit. The mirror unit includes multiples pairs of the first and second mirror surfaces, and the respective intersection angles of the multiples pairs are different from each other. In one rotation of the mirror unit, light flux emitted from the light source is reflected on the second mirror surfaces, and is projected sequentially, thereby to scan a measurement range in which the object is measured. Length in a sub scanning direction of the light flux and intersection angles of the multiples pairs correspond to length in a sub scanning direction of the measurement range.

An optical scan type object detecting apparatus, includes a mirror unit including a first mirror surface and a second mirror surface facing each other; a light source; and a light receiving element. A light flux is projected so as to scan by rotation of the mirror unit via the first mirror surface and the second mirror surface, and some of the light flux scattered by an object is received by the light receiving element. An area of the light flux received by the light receiving element becomes larger than an area of the light flux projected from the mirror unit. An incident angle inc of the light flux emitted from the light source relative to the first mirror surface satisfies a formula: /27<inc</2+11, where is an intersecting angle between the first mirror surface and the second mirror surface.

A system and method for marking a moving surface of a fiber optic cable is provided. The system includes a supply of the fiber optic cable, a laser generating device configured to generate a laser beam that forms markings by interacting with the material of the moving surface of the fiber optic cable. The system includes a movement device moving the fiber optic cable through the system at a speed of at least 50 m per minute. The system includes a laser directing device located in the path of the laser beam and configured to change the path of the laser beam to direct the laser beam to a plurality of discrete locations on the moving surface to form a series of marks on the moving surface. The moving surface includes a plurality of tracking indicia to allow the position of the moving surface to be determined.

An optical scan type object detecting apparatus, includes a light source that emits a light flux with a cross section being circular, a light projecting optical system into which a light flux emitted from the light source enters, a scanning device that makes a light flux scan in a main scanning direction, and a light receiving optical system that receives by a light receiving element a part of a light flux that is made so as to scan by the scanning device and is scattered on an object. The light projecting optical system shapes a light flux emitted from the light source such that a diameter, of a light flux made so as to scan by the scanning device, in a sub-scanning direction orthogonal to the main scanning direction becomes longer than a diameter in the main scanning direction, and, makes the shaped light flux enter the scanning device.

A scanning optical system, includes a mirror unit having a first mirror surface and a second mirror surface which incline to a rotation axis; and a light projecting system having a light source. A light flux emitted from the light source is reflected on the first mirror surface of the mirror unit, thereafter, reflected on the second mirror surface, and then, projected so as to scan in a main scanning direction onto an object in accordance with rotation of the mirror unit. In the case where a virtual plane is set in a range including the object, a light flux reflected on the second mirror surface has, upon entering the virtual plane, a cross sectional shape in which a length in a direction orthogonal to the main scanning direction is longer than a length in the main scanning direction.

A system and method for marking a moving surface of a fiber optic cable is provided. The system includes a supply of the fiber optic cable, a laser generating device configured to generate a laser beam that forms markings by interacting with the material of the moving surface of the fiber optic cable. The system includes a movement device moving the fiber optic cable through the system at a speed of at least 50 m per minute. The system includes a laser directing device located in the path of the laser beam and configured to change the path of the laser beam to direct the laser beam to a plurality of discrete locations on the moving surface to form a series of marks on the moving surface. The moving surface includes a plurality of tracking indicia to allow the position of the moving surface to be determined.

A light scanning type object detecting device includes a mirror unit in which first and second mirror surfaces are formed so as to incline in respective directions intersecting with a rotation axis and to face each other with a predetermined angle, a light source; and a light receiving element. On the assumption that H represents a distance between an intersection point of extension lines of lateral sides and a bottom side in the first mirror surface, r represents a radius of a received light flux, h represents a distance between the center of the received light flux and the bottom side, and H represents a distance between a top side and the bottom side, formulas (1) and (2) are satisfied.

when r<0.4H, 0.1<h/H(Hr)/H (1)

when r0.4H, 0.2<h/H(Hr)/H (2)

The present invention provides a scanning optical system and radar that can suppress longitudinal distortion and spot rotation of a spot light radiated on an object. A light flux emitted from a light source is reflected on a first mirror surface of a mirror unit, then, proceeds to a second mirror surface, further is reflected on the second mirror surface, and is projected so as to scan on an object correspondingly to rotation of the mirror unit. The light flux emitted from the light projecting system is made longer in a sub scanning angle direction than in a scanning angle direction in a measurement range of the object and satisfies the following conditional expression, |190|||255 . . . (1); in the expression, 1 is an intersection angle () between the first mirror surface and the second mirror surface, and is a rotation angle ().

A pixel clock generating device includes a high-frequency clock generator, a comparer, a pixel clock generator, and a value switcher. The high-frequency clock generator is configured to generate a high-frequency clock. The comparer is configured to measure a time interval between a leading-end synchronizing signal and a trailing-end synchronizing signal in a main scanning and calculate an error between the time interval and a target value. The pixel clock generator is configured to generate a pixel clock based on the high-frequency clock and a pixel clock frequency and correct the pixel clock based on the error. The value switcher, including a plurality of groups of values with which the pixel clock is generated, is configured to switch between the plurality of groups of values according to a switching signal after the trailing-end synchronizing signal is inputted, the comparer calculates the error, and the pixel clock generator corrects the pixel clock.