Asahi Kogaku Kogyo Kabushiki Kaisha

Asahi Kogaku Kogyo K.k.

Eiji Takasugi

Tsutomu Sato

Takashi Sasaki

Takashi Iizuka

Mitsunori Iima

Masatoshi Takano

Yoshiyuki Araki

Shinji Kikuchi

Hiroyuki Saito

Masato Hara

Masaaki Niiho

Shinichi Suzuki

Atsumi Kaneko

Koji Tsuda

Ryouji Honda

Toshifumi Kinba

A cascade scanning optical system which includes: a first laser scanning optical system having a first polygon mirror, provided with a plurality of first reflecting surfaces, for deflecting a first scanning laser beam to scan a part of a scanning surface to generate a first scanning line; a second laser scanning optical system having a second polygon mirror, provided with a plurality of second reflecting surfaces, for deflecting a second scanning laser beam to scan another part of the scanning surface to generate a second scanning line, wherein the first and second laser scanning optical systems are arranged so as to align the first scanning line with the second scanning line at a point of contact therebetween in a main scanning direction to form a single scanning line; means for measuring a degree of tilt of each of the plurality of first reflecting surfaces and the plurality of second reflecting surfaces; and means for determining combinations of the plurality of first reflecting surfaces with the plurality of second reflecting surfaces in accordance with results of measurements of the measuring means so that the single scanning line is formed by any one of the combinations while minimizing a phase difference between a first phase formed by degrees of tilt of the plurality of first reflecting surfaces and a second phase formed by degrees of tilt of the plurality of the second reflecting surfaces.

Synchronizing apparatus of a cascade scanning optical system having

Disclosed is a scanning apparatus having a cascade scanning optical system. The scanning apparatus includes: a first laser scanning optical system for deflecting a first scanning laser beam to scan a scanning surface to generate a first scanning line; a second laser scanning optical system for deflecting a second scanning laser beam to scan the scanning surface to generate a second scanning line, wherein the first and second laser scanning optical systems are arranged so as to align the first scanning line with the second scanning line in a main scanning direction to form a single scanning line, with opposing ends of the first and second scanning lines overlapping each other by a predetermined amount; and a device for delaying the commencement of the writing of each scanning line made by the second laser scanning optical system with respect to the commencement of the writing of each scanning line made by the first laser scanning optical system so as to align the first scanning line with the second scanning line at a point of contact therebetween in the main scanning direction without the first scanning line overlapping the second scanning line.

Scanning apparatus having a cascade scanning optical system

Disclosed is a scanning apparatus having a cascade scanning optical system. The scanning apparatus includes: a first scanning optical system for deflecting a first scanning laser beam to scan a scanning surface; a second scanning optical system for deflecting a second scanning laser beam to scan the scanning surface, wherein each of the first and second scanning optical systems is a telecentric system; a beam splitter positioned such that a first portion of the first scanning laser beam which has been reflected by the beam splitter and a first portion of the second scanning laser beam which has passed through the beam splitter proceed to the scanning surface on a common line thereon extending in a main scanning direction in respective different adjacent ranges of the common line to generate a single scanning line on the scanning surface by a combination of the first portion of the first scanning laser beam and the first portion of the second scanning laser beam; and a first laser beam detector fixed at a position to detect a second portion of the first scanning laser beam which has passed through the beam splitter and a second portion of the second scanning laser beam which has been reflected by the beam splitter when the first and second laser beams start scanning the respective different adjacent rang of the common line.

Disclosed is a scanning apparatus having a cascade scanning optical system. The scanning apparatus includes: a first laser scanning optical system for deflecting a first scanning laser beam to scan a scanning surface to generate a first scanning line during modulation of the first scanning laser beam in accordance with first given image data; a second laser scanning optical system for deflecting a second scanning laser beam to scan the scanning surface to generate a second scanning line during modulation of the second scanning laser beam in accordance with second given image data, wherein the first and second laser scanning optical systems are arranged so as to align the first scanning line with the second scanning line at a point of contact therebetween in a main scanning direction to form a single scanning line; a first laser beam detector fixed at a position to detect the first scanning laser beam before the first scanning laser beam starts generating the first scanning line; a second laser beam detector fixed at a position to detect the first scanning laser beam after the first scanning laser beam has completed generating the first scanning line; a measuring device for measuring a time interval; a determining device for determining a time-delay interval; and an adjusting device for adjusting the time at which the first scanning line starts to be generated, in accordance with the time-delay interval.

A cascade scanning optical system which includes a plurality of laser scanning optical systems each emitting a laser beam to scan a surface of a member, and a beam splitter positioned in an optical path between the plurality of laser scanning optical systems and the member such that a first laser beam which has passed through the beam splitter and a second laser beam which has been reflected by the beam splitter proceed to the surface on a common line thereon in respective ranges of the common line. Each of the plurality of laser scanning optical systems is desinged as a telecentric system.

Cascade scanning optical system

A cascade scanning optical system which includes: a pair of laser scanning optical systems each having a laser beam emitter and a laser beam deflector, wherein a laser beam emitted by the laser beam emitter enters the laser beam deflector so that the laser beam deflector deflects the laser beam to scan a surface of a member such that the laser beams proceed to the surface on a common line thereon in respective ranges of the common line; a pair of mirrors respectively provided in the pair of laser scanning optical systems, each of the pair of mirrors being positioned in a corresponding optical path between the laser beam deflector and the member to reflect a laser beam incident thereon toward the surface; a pair of cylindrical lenses having power in a sub-scanning direction, respectively provided in the pair of laser scanning optical systems, each of the pair of cylindrical lenses being positioned in a corresponding optical path between the laser beam emitter and the laser beam deflector; first means for adjusting an angle of at least one of the pair of mirrors relative to the surface; and second means for adjusting a position of at least one of the pair of cylindrical lenses relative to a corresponding one of the laser beam deflectors.

A cascade scanning optical system which includes a first laser scanning optical system for emitting a first laser beam to scan a surface of a member to generate a first scanning line, and a second laser scanning optical system for emitting a second laser beam to scan the surface to generate a second scanning line, wherein the first and second laser scanning optical systems are arranged so as to combine the first scanning line with the second scanning line at a point of contact therebetween in a main scanning direction to form a single scanning line, and wherein each of the first and second laser scanning optical systems is designed as a non-telecentric system through which the incident angle of a corresponding one of the first and second laser beams relative to the surface varies in accordance with a variation in the position of a scanning spot of the corresponding one of the first and second laser beams on the surface in the main scanning direction, and further wherein an incident angle of each of the first and second laser beams relative to the surface in the vicinity of the point of contact is predetermined to be larger than an incident angle of the same in the vicinity of a corresponding one of opposite ends of the single scanning line.

A surveying instrument for measuring a rotation angle in which a rotation angle is measured from a reference direction and is displayed. The reference angle is set by zeroing the displayed angle. The display is zeroed only if a reset button is operated twice within a fixed period.

Zero setting device in surveying instrument

An angle measuring device operating without a graduated board and of a type including a disc rotating a constant speed having a reference point fixed on the housing of a disc, an angle measuring arm concentric with the disc and rotatable, and a measuring point provided on the arm. In accordance with the invention, the ratio of an angle measuring time required for the disc to turn from the reference point to the measuring point to a one-revolution time of the disc is multiplied by 360.degree. to obtain an angle which is determined by the reference point, the center of the disc and the measuring point. This is effected with an angle measuring time integrating device for integrating data points corresponding to one-revolution time for each revolution of the disc, and an arithmetic unit for calculating a measured angle according to the ratio of the integrated value of the angle measuring times to the integrated value of the one-revolution times after the disc has made a predetermined number of revolutions.

Angle measuring device

An improved angle measuring device in which rotational irregularity in the form of two cycles or more per rotational cycle of the motor driving device is compensated for completely. A period of time T.sub.1 required for a cutout formed in the periphery of a rotor rotating at a constant speed to make one revolution starting from a stationary reference point, and a period of time T.sub.2 required for the cutout to move between the reference point and an angle measuring point are obtained to evaluate 360.degree..times.(T.sub.2 /T.sub.1) to obtain the angle under measurement. The cutout has an angular width of approximately 90.degree., although angular widths in a range of 5.degree. to 355.degree. can be used as the situation demands.

Growing community of inventors

Saitama-ken, Japan

Eiji Takasugi