Image formation apparatus and method of stabilizing the emission level of semiconductor laser source used therein
AssigneeToshiba Tec Kabushiki Kaisha
InventorsJun Sakakibara, Koji Tanimoto, Kenichi Komiya, Toshimitsu Ichiyanagi, Naoaki Ide, Koji Kawai
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Abstract
The emission level of a laser source at the non-imaging time when image data “0” is input and the emission level at the imaging time when image data “1” is input are controlled so that each of them becomes a desired level. The light output intensity is stabilized at all times regardless of variations in ambient temperature. As a result, images uniform in density can be obtained.
Claims12
An image formation apparatus for forming an image on an image carrier by scanning an imaging region on the image carrier and a non-imaging region with a laser beam emitted from a semiconductor laser source, comprising:
- a detector for detecting the emission level of the laser source;
- a first emission level control unit which controls a drive current supplied to the laser source on the basis of the result of detection by the detector so that the laser source emits light at a predetermined spontaneous emission level at the time no image is formed by the laser source;
- and
- a second emission level control unit which controls the drive current applied to the laser source on the basis of detection by the detector so that the laser source emits light at a first laser emission level at the time an image is formed by the laser source.
An image formation apparatus for forming an image on an image carrier by scanning a laser beam emitted from a semiconductor laser source across the image carrier through an optical system, comprising:
- a detector for detecting the emission level of the laser source;
- a first adjust unit which adjusts variations in the detecting efficiency of the detector;
- a first emission level control unit which controls a drive current supplied to the laser source on the basis of the result of detection by the detector so that the laser source emits light at a predetermined spontaneous emission level at the time no image is formed by the laser source;
- a second emission level control unit which controls the drive current applied to the laser source on the basis of detection by the detector so that the laser source emits light at a first laser emission level at the time an image is formed by the laser source;
- and
- a second adjust unit which compensates for variations in attenuation characteristics of the optical system.
A method of controlling an emission level of a laser source, said method being used with an image formation apparatus for forming an image on an image carrier by scanning an imaging region on the image carrier and a non-imaging region, with a laser beam emitted from the laser source, said method comprising:
- a first step of detecting the emission level of the laser source;
- a second step of controlling a drive current supplied to the laser source on the basis of the result of detection by the first step so that the laser source emits light at a predetermined spontaneous emission level at the time no image is to be formed by the laser source;
- and
- a third step of controlling the drive current applied to the laser source on the basis of the result of the detection by the first step so that the laser source emits light at a first laser emission level at the time an image is to be formed by the laser source.
Dependencies are inferred from the claim text.