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US20040218959: OPTICAL BEAM SCANNING DEVICE AND IMAGE FORMING APPARATUS

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Filing Information

Inventor(s) Takashi Shiraishi ·
Assignee(s) KABUSHIKI KAISHA TOSHIBA · TOSHIBA TEC KABUSHIKI KAISHA ·
Correspondent FOLEY AND LARDNER SUITE 500 ·
Application Number US10428032
Filing date 05/02/2003
Publication date 11/04/2004
Predicted expiration date 05/02/2023
U.S. Classifications 400/118.2  ·
International Classifications B41J002/385  ·
Kind CodeA1
27 Claims, 26 Drawings


Abstract

The purpose of an optical beam scanning device and an image forming apparatus of the invention is to decrease a deflection angle required for horizontal synchronization and to achieve preferable image forming precision by appropriately obtaining information including registration correction information though reduced deflection angle. The optical beam scanning device of the invention includes plural light sources, a pre-deflection optical unit, a light deflection unit, a post-deflection optical unit, and a horizontal synchronization unit. One of the formed plural latent images is formed by plural light beams while the other latent images are respectively formed by one light beam, and the light deflection unit deflects the light beams forming the plural latent images by one surface or integrally processed surface thereof. The horizontal synchronization unit is on a position of an upstream side of scanning lines forming the latent image formed by the plural light beams and detects that the light beam forming the latent image formed by the plural light beams reaches a predetermined position. The image forming apparatus of the invention employs the optical beam scanning device of the invention and controls timing to form images by the respective light beams with reference to a moment when the light beam to be detected reaches a predetermined position.

Independent Claims | See all claims (27)

  1. 1. An optical beam scanning device comprising: a plurality of light sources; a pre-deflection optical unit for providing predetermined characteristics for light beams from the plurality light sources; one light-deflection unit for deflecting, in a predetermined direction, the plurality of light beams provided with the predetermined characteristics by the pre-deflection optical unit; a post-deflection optical unit for causing the plurality of light beams deflection-scanned with the light-deflection unit to image on scanned surfaces, so that a plurality of latent images are formed; and an only one horizontal synchronization unit for which the plurality of light sources passed through at least a part of the post-deflection optical unit are provided; wherein said pre-deflection optical unit, said light-deflection unit and said post-deflection optical unit operate so that one of the latent images to be formed is formed by the plurality light beams while the other latent images are respectively formed by one light beam; said light-deflection unit deflects the light beams which form the plurality of latent images by one surface or an integrally processed surface thereof; said horizontal synchronization unit which is on a position of an upstream side of scanning lines forming a latent image formed by the plurality of light beams and is positioned to detect that a light beam forming the latent image formed by the plurality of light beams reaches a predetermined position; and at a time of forming the latent image, writing timing for all of the latent images is determined based on a signal from said only horizontal synchronization unit.
  2. 4. An image forming apparatus comprising: an optical beam scanning device forming the plurality of latent images; and an image writing control unit; wherein said optical beam scanning device forms one of the plurality of latent images, which are to be formed, with a plurality of light beams while forming the other latent images respectively by one light beam and includes: a plurality of light sources; a pre-deflection optical unit for providing predetermined characteristics for the plurality of light beams from the plurality of light sources; one light-deflection unit for deflecting, in a predetermined direction, light beam bundles from said pre-deflection unit, which light beam bundles form the plurality of latent images with one surface or an integrally processed surface; a post-deflection optical unit for causing the plurality of light beams deflection-scanned with the light-deflection unit to image on corresponding respective scanned surfaces, so that the plurality of latent images are formed; a horizontal synchronization unit which is on a position of an upstream side of scanning lines by a light beam, which light beam forms a latent image formed by the plurality of light beams, among the plurality of light beams passed through a part of the post-deflection optical unit and detects that the each light beam forming the latent image formed by the plurality of light beams reaches a predetermined position; and in an image forming mode, after said horizontal synchronization unit detects that, one of the plurality of light beams forming the latent image formed by the plurality of light beams reaches a predetermined position, said image writing control unit performs on-off control of said respective light sources for the detected light beam and for the each light beam forming one latent image by the one light beam in accordance with image data after a predetermined time period defined by a registration correction information at that time elapses.
  3. 16. An image forming apparatus comprising: an optical beam scanning device forming a plurality of latent images; and an image writing control unit; wherein said optical beam scanning device forms at least two of the plurality of latent images, which are to be formed, with a plurality of light beams and includes: a plurality of light sources; a pre-deflection optical unit for providing predetermined characteristics for the plurality of light beams from the plurality of light sources; one light-deflection unit for deflecting, in a predetermined direction, light beam bundles from said pre-deflection unit, which light beam bundles form the plurality of latent images with one surface or an integrally processed surface; a post-deflection optical unit for causing the respective light beams deflection-scanned with the light-deflection unit to image on corresponding respective scanned surfaces, so that the plurality of latent images are formed; an only horizontal synchronization unit which is on a position of an upstream side of scanning lines by a light beam, which light beam forms a latent image formed by the plurality of light beams, among a plurality of light beams passed through at least a part of the post-deflection optical unit and detects that each light beam forming the latent image formed by the plurality of light beams reaches a predetermined position; and in an image forming mode, with respect to each of the plurality of light beams forming one latent image, said image writing control unit controls timing to begin on-off based on image data for each light beam as a basis for timing when a reference light beam passes through a predetermined position of said horizontal synchronization unit and a time difference or correction information thereof between the reference light beam and the light beam when the light beam passes through the predetermined position of the horizontal synchronization unit, said time difference or correction information thereof being held in a registration correction mode.
  4. 22. An optical beam scanning device comprising: a plurality of light sources; a pre-deflection optical unit for providing predetermined characteristics for a plurality of light beams from the plurality of light sources; one light-deflection unit for deflecting, in a predetermined direction, light beam bundles provided with the predetermined characteristics by the pre-deflection optical unit; a post-deflection optical unit for causing respective light beams deflection-scanned with the light-deflection unit to image on corresponding respective scanned surfaces, so that a plurality of latent images are formed; and a horizontal synchronization unit for which the plurality of light beams passed through at least a part of the post-deflection optical unit are provided; wherein said pre-deflection optical unit, said light-deflection unit, and said post-deflection optical unit operate so that at least two of the latent images to be formed are formed by the plurality light beams; said light-deflection unit deflects the light beams forming the plurality of latent images by one surface or an integrally processed surface thereof; said horizontal synchronization unit includes a reflection mirror unit and a detection sensor unit, said reflection mirror unit having, with respect to each set of the plurality of light beams forming respective latent images, the same reflecting angle in a main-scanning direction while having respectively different reflecting angles in a sub-scanning direction, the sets of the plurality of light beams forming respective latent images being reflected by so as to intersect at a position equivalent to a predetermined image surface and said detection sensor unit being provided at an intersecting position of the sets of plurality of light beams reflected by said reflecting mirror unit, which light beams form the respective latent images, so that the respective light beams are detected.
  5. 24. An image forming apparatus comprising: an optical beam scanning device including a light-deflection unit deflection-scanning a light beam emitted from a light source and a post-deflection optical unit causing the deflection-scanned light beam to image on a scanned surface; said image forming apparatus having: a horizontal synchronization optical unit for which a light beam passed through at least a part of said post-deflection optical unit is provided and which detects that the light beam reaches a first and a second predetermined positions being distanced by a predetermined distance in a main-scanning direction; and a registration measuring image writing control unit which controls latent image forming of a registration measuring image with reference to said first predetermined position and of the registration measuring image with reference to said second predetermined position.

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Referenced By

Document NumberAssigneeInventorsIssue/Pub Date
US8107833 Ricoh Company, Ltd. Yoshiki Yoshida Jan 2012

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