Patent · US Active

Image forming apparatus having a exposure control unit capable of changing an exposure ratio between a first exposure ratio and a second exposure ratio different from the first exposure ratio when a first exposure unit or second exposure unit exposes an image carrier on the basis of image data for forming an image with a certain density

US7742067B2 · kind B2 · utility

0Cited by
1References
9Claims
0Family size

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Inventors

Key dates

Filing dateMay 14, 2008
Grant dateJun 22, 2010
Priority date—
Expiry dateMay 21, 2028

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG03G15/0435
  • WIPO fieldOptics
  • WIPO sectorInstruments

Abstract

In an early-middle stage of a photosensitive drum life cycle, an image forming apparatus uses only a second semiconductor laser having an oscillation wavelength 660 nm to perform writing of an electrostatic latent image on a photosensitive drum surface. In a middle-late stage of the photosensitive drum life cycle, the image forming apparatus starts using a first semiconductor laser having an oscillation wavelength of 440 nm in addition to the second semiconductor laser to perform writing of an electrostatic latent image on the photosensitive drum surface with a combined exposure spot formed at the same position. An exposure control unit gradually increases an output rate of the first semiconductor laser according to an increase in total output of the first and second semiconductor lasers.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.