US 5,179,392 A · Multi-color image forming apparatus

Abstract

A multi-color image forming apparatus forming an image of a plurality of colors in one processing by using a plurality of laser beams and a plurality of developing devices, in the case where any of the laser beams becomes unusable during forming a mono-color image, makes the image data to have been outputted from the laser beam to be replaced by that of another laser beam which can be usable, then to output it. The apparatus, in the case where any of the laser beams and developing devices become unusable because of trouble caused therein during forming an image of a plurality of colors, forms an image as an emergency measure by using the remaining usable laser beams or developing devices. Moreover, in the case where any of the laser beams and developing devices for any color become unusable because of trouble caused therein during forming an image of a plurality of colors, express the color by changing the density of another color.

Claims28

Dependent claims

A multi-color image forming apparatus, comprising:

an image holding medium, being rotated in a predetermined direction, for holding electrostatic latent image formed thereon;
light irradiating means, which has a plurality of light sources being disposed in the circumferential direction of said image holding medium and irradiating light including image information, for irradiating on a plurality of portions on said image holding medium to form respective electrostatic latent images in said respective portions;
trouble detecting means for detecting light emission troubles caused in said plurality of light sources, respectively;
and
light irradiation controlling means,
in the case where light emission trouble has not been detected by said trouble detecting means, for controlling said plurality of light sources to irradiate image informations which correspond to said plurality of light sources, respectively, and
in the case where light emission trouble has been detected by said trouble detecting means, for controlling the light source in which trouble has been detected to be in non-operation state, and for controlling any of light sources in which trouble has not been detected to irradiate image information to have been irradiated by said light source in which trouble is detected.

4 more elements

A multi-color image forming apparatus, comprising:

an image holding medium, being rotated in a predetermined direction, for holding electrostatic latent image formed thereon;
a plurality of laser beam sources each of which, being disposed in the circumferential direction of said image holding medium, oscillates laser beams corresponding to image data;
optical scanning means for scanning laser beam oscillated from said plurality of laser beam sources and irradiating it on a plurality portions of said image holding medium, respectively;
a plurality of developing means, containing therein developers of different colors from each other, for developing electrostatic latent images, respectively formed on said image holding medium by said optical scanning means;
trouble detecting means for detecting each oscillation trouble of said plurality of laser beam sources;
and
beam oscillation controlling means,
in the case where oscillation trouble of said plurality of laser beam sources has not been detected by said oscillation trouble detecting means, for controlling said plurality of laser beam sources to actuate, and
in the case where oscillation trouble has been detected in any of said plurality of laser beam sources by said oscillation trouble detecting means, for controlling the laser beam source not to actuate in which trouble has been detected, and for controlling any of laser beam source to actuate in which trouble has not been detected by said trouble detecting means inside the laser beam source which is one of the laser beam sources irradiating upstream side portions than the portion which is irradiated by said laser source in which trouble is detected in the direction of rotation of said image holding medium.

6 more elements

A multi-color image forming apparatus, comprising:

an image holding medium for holding electrostatic latent image formed thereon;
image exposing means, having a plurality of light sources each of which generates beam corresponding to image data of a predetermined color including density information, for irradiating a plurality of portions on said image holding medium, respectively to expose them;
trouble detecting means for detecting each light emission trouble of said plurality of light sources;
image data density changing means, in the case where trouble has been detected in any of said plurality of light sources by said trouble detecting means, for changing a density information of image data corresponding to the beam to be outputted from a light source to a density information of different density;
image data composing means for composing the image data whose density has been changed by said image data density changing means with image data corresponding to the beam outputted from a normal light source;
and
image forming means for forming an image using said normal light source on the basis of the image data composing by said image data composing means.

4 more elements

A multi-color image forming apparatus, comprising:

an image holding medium for holding an electrostatic latent image formed thereon;
image exposing means, having a plurality of light sources which generate beam corresponding to an image data of a predetermined color having density information, for forming, by irradiating on a plurality of portions on said image holding medium to expose, on the respective portions electrostatic latent images which correspond to respective colors;
a plurality of developing means, containing developers of different colors from each other, for developing a plurality of electrostatic latent images, respectively formed on said image holding medium by said image exposing means;
development trouble detecting means for detecting generations of troubles in said respective developing means;
image data density changing means, in the case where trouble is detected at least in one of said plurality of developing means by said trouble detecting means for changing a density information of an image data corresponding to the beam which forms electrostatic latent image to be developed by a developing means in which trouble has been detected;
image data composing means for composing an image data whose density has been changed by said density changing means of an image data with an image data whose density has not been changed;
and
image forming means for forming an electrostatic latent image on said image holding medium on the basis of an image data composed by said image data composing means and for making a developing means, in which trouble has not been detected by said development trouble detecting means, develop the formed electrostatic latent image.

5 more elements