US 5,311,216 AGranted

Exposure device having means for correcting intensity of laser beam dependent on variation in rotational speed of photosensitive member

AssigneeBrother Kogyo Kabushiki Kaisha

InventorsShinichi Hirahata, Tsuyoshi Ohashi

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Abstract

In an image recording apparatus including a rotary drum on which a photosensitive sheet is wound, the drum is rotated by a motor through a speed reduction gear assembly to rotate at a constant speed V. To maintain an average exposure amount applied to the photosensitive sheet at constant as it is not the case when the rotational or peripheral speed of the drum vary due to a backlash of the speed reduction gears or a load imposed on the drum, a speed detector is attached to the shaft of the drum to detect the rotational speed of the drum. Based on the detected rotational speed, the exposure amount is increased or decreased by .DELTA.V/V times as much as the average exposure amount where V is a regular rotational speed of the drum and .DELTA.V is a variation in the drum speed from the speed V.

Claims15

Dependent claims

An exposure device for forming a latent image on a photosensitive recording member, comprising:

image data generating means for generating image data having a level;
moving means for moving the recording member at a regular speed which is subject to variation;
speed variation detecting means for detecting a variation of the speed at which the recording member is moved, and for producing speed variation data having a level indicative of the variation in the speed of the recording member;
a semiconductor laser, having an input to which a signal having a level is applied, for emitting a laser beam onto the recording member, an intensity of the laser beam being variable dependent on the level of the signal applied to the input of said semiconductor laser;
and
correction means for correcting the intensity of the laser beam in accordance with the speed variation data, said correction means comprising storage means for storing groups of data, wherein said correction means:
1) applies the image data to one of the groups of data and applies the speed variation data to another of the groups of data to produce corrected image data;
and
2) outputs the corrected image data for application to the input of said semiconductor laser.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/772,788Filed 8 Oct 1991
Priority: JP 2-2715228 Oct 1990
Granted: 10 May 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

H04N 1/4005
Circuits exciting or modulating particular heads for reproducing continuous tone value scales: with regulating circuits, e.g. dependent upon…
H04N 1/0473
Detection, control or error compensation of scanning velocity or position: in subscanning direction, e.g. picture start or line-to-line…
H04N 1/40037
Circuits exciting or modulating particular heads for reproducing continuous tone value scales: the reproducing element being a laser
H04N 1/407
Picture signal circuits: control or modification of tonal gradation or of extreme levels, e.g. background level