Multi-color image forming apparatus

• US 5,179,392 A
• Filed: 04/04/1991
• Issued: 01/12/1993
• Est. Priority Date: 04/05/1990
• Status: Expired due to Term

• Current Assignee: Minolta Camera Kabushiki Kaisha
• Original Assignee: Minolta Camera
• Inventors: Kawaguchi, Toshikazu
• Primary Examiner(s): Reinhart, Mark J.
• Application Number:
  US07/681,325
• Time in Patent Office: 649 Days
• Field of Search: 346/108, 346/160, 358/296, 358/298, 358/300, 355/205, 355/202, 355/245
• US Class Current: 347/118
• CPC Class Codes: H04N 1/19 using multi-element arrays
• CPC Class Codes: H04N 1/1906 Arrangements for performing substitution scanning for a defective element
• CPC Class Codes: H04N 1/506 Reproducing the colour component signals picture-sequentially, e.g. with reproducing heads spaced apart from one another in the subscanning direction

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.

Claims

1. 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.

2. A multi-color image forming apparatus as set forth in claim 1, wherein

said light irradiation controlling means uses a light source which irradiates on a more upstream portion of the rotational direction of said image holding medium in the case where light emission trouble has been detected in any of said light sources.

3. A multi-color image forming apparatus as set forth in claim 2, further comprising:

a plurality of developing means for developing a plurality of electrostatic latent images formed on said image holding medium by said light irradiating means.

4. A multi-color image forming apparatus as set forth in claim 2, wherein

said trouble detecting means is incorporated with said light irradiating means.

5. 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. A multi-color image forming apparatus as set forth in claim 5, wherein

at least one laser beam source of said plurality of laser beam sources oscillates laser beam of different wave length from that of other laser beam sources.

7. A multi-color image forming apparatus as set forth in claim 6, wherein

said trouble detecting means is incorporated with said optical scanning means.

8. 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.

9. A multi-color image forming apparatus as set forth in claim 8, wherein

said image data density changing means, having a memory in which density information to be changed is stored, for changing density information of an inputted image data to density information stored in said memory, and for outputting the changed image data.

10. A multi-color image forming apparatus as set forth in claim 9, wherein

said image data composing means is provided with a logical circuit which carries out logical add operation of one image data of changed color and the other image data of unchanged color in order to compose said both image data.

11. A multi-color image forming apparatus as set forth in claim 8, wherein

said image forming means includes a plurality of developing devices which, respectively contain developers of different colors from each other, and develops an electrostatic latent image formed on said image holding medium on the basis of said composed image data by using a developing devices having a desired color.

12. A multi-color image forming apparatus as set forth in claim 11, further comprising:

developing devices trouble detecting means for detecting generations of troubles in said plurality of developing devices, respectively.

13. A multi-color image forming apparatus as set forth in claim 12, wherein

said trouble is toner empty state.

14. 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.

15. A multi-color image forming apparatus as set forth in claim 14, wherein

said image data density changing means having a memory in which density information to be changed is stored, for changing density information of an inputted image data to density information stored in said memory, and for outputting the changed image data.

16. A multi-color image forming apparatus as set forth in claim 15, wherein

said image data composing means is provided with a logical circuit which carries out logical add operation of one image data of changed color and the other image data of unchanged color in order to compose said both image data.

17. A multi-color image forming apparatus as set forth in claim 14, wherein

said trouble is the toner empty state.

18. A two-color image forming apparatus, comprising:

an image holding medium for holding electrostatic latent image formed thereon;

two exposing means for forming electrostatic latent images which correspond to two colors at different portions, by irradiating and exposing the two different portions in the circumferential direction of said image holding medium by means of two beams corresponding to image data of the two colors including density information;

light emission trouble detecting means for detecting respective light emission troubles of said two exposing means;

two developing means, containing developers of different colors from each other, for developing two electrostatic latent images formed on said image holding medium by said image exposing means;

development trouble detecting means for detecting generation of trouble in said two developing means, respectively;

image data density changing means, in the case where at least trouble of either one of exposing means or one of the two developing means has been detected by said light emission trouble detecting means or said development trouble detecting means for changing information of image data of a color corresponding to exposing means or developing means in which trouble has detected been to density information of another density;

image data composing means for composing image data whose density has been changed by said image data density changing means with image data whose density has not been changed; and

image forming means for forming image by using said exposing means or said developing means which correspond to another color on the basis of image data composed by said image data composing means.

19. A two-color image forming apparatus as set forth in claim 18, wherein

said image data density changing means, having a memory in which density information to be changed is stored, for changing density information of an inputted image data to density information stored in said memory, and for outputting the changed image data, and

said image data composing means is provided with a logical circuit which carries out logical add operation of one image data of changed color and the other image data of unchanged color in order to compose said both image data.

20. A two-color image forming apparatus, comprising:

an image holding means, being rotated in a predetermined direction, for holding electrostatic latent image formed thereon;

two laser beam sources each of which beind 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 two laser beam sources and irradiating it on two portions of said image holding medium, respectively;

two developing means, containing therein developers of different colors from each other, for developing two electrostatic latent images, respectively formed on said image holding medium by said optical scanning means;

trouble detecting means for detecting respective oscillation troubles of said two laser beam sources; and

beam oscillation controlling means,

in the case where oscillation trouble of said two of laser beam sources has not been detected by said oscillation trouble detecting means, for controlling said two laser beam sources to actuate, and

in the case where oscillation trouble has been detected in one laser beam source which irradiate a portion at the downstream side in the rotational direction of said image holding means of said two laser beam sources and oscillation trouble has not been detected in other laser beam source which irradiate a portion at the upstream side in the rotational direction of said image holding means of said two laser beam sources by said oscillation trouble detecting means, for controlling said one laser beam source at downstream side not to actuate, and for controlling a laser beam source at upstream side to actuate.

21. A two-color image forming apparatus as set forth in claim 20, wherein

said two laser beam sources oscillate respective laser beams of different wave lengths from each other.

22. A two-color image forming apparatus as set forth in claim 21, wherein

said trouble detecting means is incorporated with said optical scanning means.

23. A two-color image forming apparatus, comprising:

an image holding medium, being rotated in a predetermined direction, for holding electrostatic latent image formed thereon;

exposing means, which includes a first light source outputting beam therefrom corresponding to image data of a first color and a second light source outputting beam therefrom corresponding to an image data of a second color, for forming at two portions, respectively electrostatic latent images corresponding to two colors by irradiating different portions of said image holding medium in the circumferential direction;

light emission trouble detecting means for detecting light emission trouble of said first and second light sources;

developing means including therein a first developing device which stores first developer of said first color and a second developing device which stores second developer of said second color, for developing two electrostatic latent images formed on said image holding medium by said first and second light sources;

mode selecting means for selecting a first mono-color mode forming an image of said first color by using said light source and said developing device corresponding to a first color, or for selecting a second mono-color mode forming an image of said second color by using said light source and said developing device corresponding to a second color, or for selecting two-color mode forming image of two color by using said exposing means and said developing means during one operation of forming image; and

image data processing means, in the case where said two-color mode is selected by said mode selecting means and trouble has not been detected by said light emission trouble detecting means, for changing a density information of image data of one color corresponding to beam to be outputted from the light source in which trouble has been detected to a density information of another density, and for composing the image data whose density information has been changed with the image data of another color to output the composed image data.

24. A two-color image forming apparatus as set forth in claim 23, wherein

said image data processing means including a logical circuit and a memory which stores density information to be changed, for changing an inputted density information of an image data to a stored density information, and for carrying out logical-add operation of said data of one color whose density information has been changed and the image data of another color whose density has not been changed to composing said both image data.

25. A two-color image forming apparatus as set forth in claim 23, further comprising:

development trouble detecting means for detecting generation of trouble at respective said first and second developing devices.

26. A two-color image forming apparatus as set forth in claim 23,

image forming executing means for executing image forming operation corresponding to a mode selected by said mode selecting means and for operating a developing device in which trouble has not been detected by said development trouble detecting means on the basis of said composed data outputted from said image data processing means.

27. A two-color image forming apparatus, comprising:

an image holding medium, being rotated in a predetermined direction, for holding electrostatic latent image formed thereon;

exposing means, which includes a first light source outputting beam therefrom corresponding to image data of a first color and a second light source outputting beam therefrom corresponding to an image data of a second color, for forming at two portions, respectively electrostatic latent images corresponding to two colors by irradiating different portions of said image holding medium in the circumferential direction;

light emission trouble detecting means for detecting light emission trouble of said first and second light sources;

developing means including therein a first developing device which stores first developer of said first color and a second developing device which stores second developer of said second color, for developing two electrostatic latent images formed on said image holding medium by said first and second light sources;

mode selecting means for selecting a first mono-color mode forming an image of said first color by using said light source and said developing device corresponding to a first color, or for selecting a second mono-color mode forming an image of said second color by using said light source and said developing device corresponding to a second color, or for selecting two-color mode forming image of two color by using said exposing means and said developing means during one operation of forming image; and

an image data processing means for outputting an image data of one color corresponding to beam to be outputted from said laser beam source at the downstream side from another laser beam source, in the case where either of said mono-color modes has been selected by said mode selecting means, and has been detected at the laser beam source irradiating a portion at the downstream side in the rotational direction of said holding means inside of said two laser beam sources and light emission trouble has not been detected at the laser beam source irradiating a portion at the upstream side in the rotational direction of said holding means.

28. A two-color image forming apparatus, comprising:

an image holding medium, being rotated in a predetermined direction, for holding electrostatic latent image formed thereon;

exposing means, which includes a first light source outputting beam therefrom corresponding to image data of a first color and a second light source outputting beam therefrom corresponding to an image data of a second color, for forming at two portions, respectively electrostatic latent images corresponding to two colors by irradiating different portions of said image holding medium in the circumferential direction;

light emission trouble detecting means for detecting light emission trouble of said first and second light sources;

developing means including therein a first developing device which stores first developer of said first color and a second developing device which stores second developer of said second color, for developing two electrostatic latent images formed on said image holding medium by said first and second light sources;

mode selecting means for selecting a first mono-color mode forming an image of said first color by using said light source and said developing device corresponding to a first color, or for selecting a second mono-color mode forming an image of said second color by using said light source and said developing device corresponding to a second color, or for selecting two-color mode forming image of two color by using said exposing means and said developing means during one operation of forming image; and

image data processing means,

in the case where said two color modes are selected by said mode selecting means and trouble has been detected by said light emission trouble detecting means, for changing a density information of an image data of one color corresponding to beam to be outputted from one light source in which trouble has been detected to a density information of another density, and for composing the image data whose density information has been changed with the image data of another color to output the composed image data, and

in the case where either of said mono-color mode has been selected by said mode selecting means, and light emission trouble has been detected at the laser beam source irradiating a portion at the downstream side in the rotational direction of said holding medium inside of said two laser beam sources by said light emission trouble detecting means and light emission trouble has not been detected at the laser beam source irradiating a portion at the upstream side in the rotational direction of said holding means by the same, for outputting an image data of one color corresponding to beam to be outputted from said laser beam source at downstream side from another laser beam source.