JP2010017945A - Laser switching system of electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, when one luminescence channel becomes not capable of normal operation due to the failure or degradation, even if other luminescence channels can be used, laser array itself needs the replacement by a maintenance worker or a customer, which requires the huge maintenance time and a high skill for a readjustment of optical unit, and thereby increases the running cost. <P>SOLUTION: An electrophotographic device is equipped with: a multi-beam laser which has two or more luminescence channels and is arranged in the paper feed direction; and a multi-beam scan optical system which periodically polarizes two or more laser beams irradiated from the multi-beam laser using a spinning multiple mirror, and makes an electrostatic latent image formed by conducting a parallel scanning simultaneously on a medium to be scanned. In the electrophotographic device, at least a multi-beam laser number n has a two or more integer times of the beam number m required for the electrophotographic device, and it is used from the front m beam of to the paper feed direction, and it is changed to the back per m beams at the time of failure occurrence. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser switching method for an electrophotographic apparatus.

  In electrophotographic apparatuses such as digital printers and digital copying machines, since high-quality images can be stored at high speed, electrophotographic apparatuses that form images using a laser beam emitted from a laser light source such as a semiconductor laser are widely used. is doing. In order to meet the demand for further speeding up, such an electrophotographic apparatus supports a multi-beam laser. As an example of a multi-beam method, a plurality of light emitting channels for emitting a laser are provided on one chip. Arrayed laser diode arrays or fiber arrays using fibers are becoming increasingly popular. As this kind of invention, for example, Patent Document 1 is cited.

JP 2004-085853 A

  However, as described above, in the laser array, when even one light emitting channel is broken or deteriorated and normal operation becomes impossible, even if other light emitting channels can be used, it is requested by maintenance personnel or customers. It is necessary to replace the laser array itself. In addition, the maintenance time is enormous, and the optical unit requiring high skill must be readjusted, which is a major factor in increasing the running cost.

  An object of the present invention is to solve the above-mentioned problems of the prior art. For example, when one combination of light emission channels becomes unusable due to deterioration or the like, the laser array is switched to a combination of spare light emission channels. As a result, the laser switching method of the electrophotographic apparatus can reduce the total running cost by extending the replacement period of the laser array and eliminating the need for optical adjustment that requires high skill. Is to provide.

  In order to achieve the above object, a first means of the present invention comprises a multi-beam laser having a plurality of light-emitting channels and arranged in a paper transport direction, and a plurality of laser beams irradiated from the multi-beam laser. In an electrophotographic apparatus comprising a multi-beam scanning optical system that periodically polarizes using a mirror and simultaneously scans on a scanned medium to form an electrostatic latent image, at least the number of multi-beam lasers is It has an integral multiple of 2 or more of the required number of beams m in the electrophotographic apparatus, is used from the front m beams with respect to the paper conveyance direction, and is switched backward in units of m when a failure occurs. It is.

  The second means of the present invention is characterized in that, in the first means, the video data transmission time is delayed by one scanning time with respect to the transmission time before the switching at the time of the switching.

  According to a third means of the present invention, in the first means, the laser is a semiconductor laser array.

  According to a fourth means of the present invention, in the first means, the laser is a fiber array of a semiconductor laser.

  A fifth means of the present invention is characterized in that, in the first means, the number of lasers n is 20.

  According to the present invention, it is possible to extend the life of the laser array, and as a result, it is possible to reduce the total running cost by extending the replacement period of the laser array and eliminating the need for optical adjustment that requires high skill. To do.

  FIG. 1 is a schematic configuration diagram of an optical scanning device used in an electrophotographic apparatus typified by a laser printer or a copying machine. The m laser beams emitted from the n laser light sources 10 are reflected by the rotary polygon mirror 20 and irradiated while scanning the photosensitive drum 40 through the Fθ lens 30. At this time, the character data or graphic data converted into a dot image becomes a video signal (laser beam ON / OFF signal), and a portion where the laser beam is irradiated and a portion where the laser beam is not irradiated are formed on the surface of the photosensitive drum 40. A so-called electrostatic latent image is formed. The rotary polygon mirror 20 is controlled at a constant speed by competing the output of the rotation sensor with the control clock. The scanning light detector 50 is installed at a position that is optically equal to the rotational scanning medium 40 and is irradiated with a laser beam before the rotational scanning medium 40 in the main scanning direction. This sensor generates a horizontal synchronizing signal, and determines the dot image transmission start position from the host controller when the scanning light scans on the rotating scanned medium 40.

  The multi-beam laser switching method will be described with reference to FIGS. FIG. 2 is a block diagram of a multi-beam laser control circuit according to an embodiment of the present invention. This multi-beam laser control circuit has a multi-beam laser 1 having a plurality of light-emitting points (light-emitting channels), a laser control unit 3 that can be controlled for each channel of the laser and can switch the light-emitting channel, and for causing the laser to emit light. The driver part 2 is comprised.

FIG. 3 is a conceptual diagram of the switching method according to the embodiment of the present invention. A scanning line of the light emitting laser before switching is shown by a solid line. A scanning line indicated by a broken line indicates a scanning line after switching when a failure occurs. As shown in this conceptual diagram, by performing switching in units of m required beams, the man-hours that the maintenance personnel originally need to adjust the writing position while printing the test sample are automatically performed by the following method Is possible.
(1) Scanning direction adjustment The writing position is corrected using the horizontal synchronizing signal.
(2) Adjustment of paper conveyance direction Since the arrangement of the multi-beam laser is determined in advance, it is possible to adjust the paper conveyance direction writing position only by delaying the dot image transmission from the controller for one scanning time.

  Therefore, according to the present invention, it is possible to reduce the work man-hours of maintenance personnel and customers.

It is a schematic block diagram of the optical scanning device used for an electrophotographic apparatus. It is a block diagram of the laser array drive circuit before the switching in the Example of this invention. It is a conceptual diagram before the switching. It is a block diagram of the laser array drive circuit after switching in the Example of this invention. It is a conceptual diagram after the switching.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Laser light source, 20 ... Rotary polygon mirror, 30 ... F (theta) lens, 40 ... Photosensitive drum, 50 ... Scanning light detection sensor, 1 ... Laser array, 2 ... Driver part, 3 ... Control part.

Claims (5)

A multi-beam laser having a plurality of light-emitting channels and arranged in the paper conveyance direction and a plurality of laser beams emitted from the multi-beam laser are periodically polarized using a rotating polygon mirror, and simultaneously on the scanned medium. In an electrophotographic apparatus including a multi-beam scanning optical system that forms an electrostatic latent image by performing parallel scanning,
At least the number of multi-beam lasers n is an integer multiple of 2 or more of the required number of beams m in the electrophotographic apparatus, and is used from m beams forward in the paper transport direction, and in units of m when a failure occurs. A laser switching method of an electrophotographic apparatus characterized by switching to the rear.   2. The laser switching method for an electrophotographic apparatus according to claim 1, wherein the video data transmission time is delayed by one scanning time with respect to the transmission time before the switching at the time of the switching.   2. The laser switching method for an electrophotographic apparatus according to claim 1, wherein the laser is a semiconductor laser array.   2. The laser switching method for an electrophotographic apparatus according to claim 1, wherein the laser is a fiber array of a semiconductor laser.   2. The laser switching method for an electrophotographic apparatus according to claim 1, wherein the number n of lasers is 20.

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