JP2002148541A - Scanning optical system and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a scanning optical device capable of effectively reducing the size of an image forming apparatus including an optical beam scanning unit and the image forming apparatus utilizing the scanning optical system. SOLUTION: In the scanning optical device having a light source means, a 1st optical member for making a luminous flux from the light source means incident on a deflection means, a reflection means for reflecting and deflecting an optical path of the luminous flux reflected and defected by the deflection means at about 90 deg., and a 2nd optical member for making the luminous flux from the reflection means incident on the surface of an image carrier and capable of optically scanning the surface of the image carrier with light by the rotation of the deflection means, each of the reflection means and the 2nd optical member is provided with an adjusting means for adjusting the posture of each means. A 1st storing part storing the deflection means and the 1st optical member and a 2nd storing part storing the reflection means and the 2nd optical member are formed like an L shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device and an image forming apparatus using the same, and more particularly, to deflecting a light beam emitted from a light source means by a deflecting element via an imaging element (scanning optical means) having f.theta. In order to record image information by optically scanning on the surface to be scanned (image carrier surface), for example, a multicolor electrophotographic copying machine of an electrophotographic type, an electrostatic recording type,
The present invention is suitable for various color copiers, color printers, and the like, such as a recording device constituting an output unit of a facsimile, a computer, or the like.

In addition, the present invention is suitable for an apparatus using a plurality of scanning optical devices in an image forming apparatus (multiplex image forming apparatus) having a plurality of image carriers.

[0003]

2. Description of the Related Art Conventionally, in an image forming apparatus employing electrophotography, a photosensitive member as an image carrier is charged by a charger, and the photosensitive member is irradiated with a laser beam light-modulated in accordance with image information. To form a latent image. Then, an image is formed by transferring a developed image obtained by developing the latent image by a developing device to a sheet material or the like.

On the other hand, in accordance with the colorization of an image, a plurality of image carriers for performing each of these image forming processes are provided, and a color image including a cyan image, a magenta image, a yellow image, and preferably a black image is added. There is also proposed a full-color image forming apparatus in which a full-color image is formed by forming each color image on a sheet material at a transfer position of each image carrier by superimposing and transferring each color image.

Since such a full-color image forming apparatus has an image forming section for each color, it is advantageous for speeding up.
Also, since the sheet material conveyance path can be configured on a straight line,
It has the advantage of being adaptable to cardboard and trapen sheet materials.

FIG. 12 is a schematic view of a main part when a conventional image forming apparatus is applied to a digital full-color copying machine.

First, a copy operation (copy operation) of the digital full-color copying machine will be described with reference to FIG. In the figure, reference numeral 8 denotes an original reading unit,
The document fixed at 6 is formed on the line sensor 81 by the reading lens 82 via the mirrors 85, 84, 83,
The image information on the document is read by the line sensor 81.

[0008] A signal from the line sensor 81 is input to a laser scanning unit, which will be described later, and performs optical modulation of laser light output from the laser scanning unit based on the signal.

Reference numeral 310 denotes a full-color image forming unit. The full-color image forming section 310 is provided with four image forming stations Pa to Pd for forming image information for each color light, and each image forming station has a photosensitive drum 2 (2a, 2b, 2c, 2d) as an image carrier.

Around the photosensitive drum 2, dedicated charging means 3 (3a, 3b, 3c, 3d) and a laser scanning unit 301 (301a) for irradiating the photosensitive drum with light corresponding to image information for each color light. , 301b, 301c, 301
d), developing means 305 (305a, 305b, 305)
c, 305d), the drum cleaning means 4 (4a, 4d)
b, 4c, 4d), transfer means 6 (6a, 6b, 6c, 6)
d) are arranged respectively. 351 (351)
a to 351d) are each one of the developing units 305a to 305d.
This is a one-to-one developer container for replenishing the developer by attaching and detaching a cylindrical developer cartridge. Here, the image forming stations Pa, Pb, P
c and Pd are where a cyan image, a magenta image, a yellow image, and a black image are formed, respectively.

On the other hand, each of the image forming stations Pa to Pd
, An endless belt-shaped intermediate transfer belt 61 is disposed below the photosensitive drums 2a, 2b, 2c, and 2d.
The intermediate transfer belt 61 is stretched around a driving roller 62 and driven rollers 63 and 65, and further provided with a cleaning unit 64 for cleaning the surface thereof.

In this configuration, first, the charging means 3a of the first image forming station Pa, the laser scanning unit 1
a latent image of the cyan component of the image information is formed on the photosensitive drum 2a by a known electrophotographic process means such as exposure by a, and the latent image is formed as a cyan toner image by a developing agent having a cyan toner in a developing means 5a. The image is visualized and the cyan toner image is transferred to the surface of the intermediate transfer belt 61 by the transfer unit 6a.

On the other hand, while the cyan toner image is being transferred onto the intermediate transfer belt 61, a magenta component color latent image is formed on the photosensitive drum 2b in the second image forming station Pb. To form a toner image with magenta toner, and the transfer unit 6b transfers the magenta toner image with high accuracy onto the intermediate transfer belt 61, which has been transferred at the first image forming station Pa.

Thereafter, image formation is performed on the yellow image and the black image in the same manner, and when the superposition of the four color toner images on the intermediate transfer belt 61 is completed, the four color toner image on the intermediate transfer belt 61 becomes At the secondary transfer roller 66,
Manual paper feed cassette (multi-purpose tray) 70
The sheet is re-transferred (secondarily transferred) onto the sheet material S which has been conveyed at the same timing by the sheet feed roller 71, the conveying roller pair 72, and the registration roller pair 73. Then, the sheet material S on which the secondary transfer has been completed is transferred to the fixing roller pair 74.
Is heated and fixed, and a full-color image is obtained on the sheet material S.

Each of the photosensitive drums 2 whose transfer has been completed
In a to 2d, residual toner is removed from each drum by cleaning means 4a to 4d to prepare for the subsequent image formation.

Reference numerals 78 and 79 denote paper cassettes.

Reference numeral 69 denotes an image position reading detection unit for removing position information of the intermediate transfer belt 61.

The laser scanning unit 30 of the copying machine shown in FIG.
1a to 1d, an optical path between the polygon mirror and the photosensitive drum and optical components are arranged on a plane perpendicular to the image carrier, and the developer accommodating means of the developing means and the laser Scanning units are provided alternately,
This reduces the width of the image forming apparatus main body. As shown in FIG. 13, each laser scanning unit is provided with a scanner for scanning a laser beam from a laser diode 319 onto a photosensitive drum at a predetermined spot diameter, which is directly fixed to a main frame (not shown) around the main body. It is arranged in case 390. The details follow the laser beam path, and the collimator lens 317, cylindrical lens 318, polygon mirror 311, cylindrical lens 312, toric lens 313, dustproof glass 3
20 and a mirror 314, a lens 315, and a sensor 316, which are write signal detection means in a partially different path. Here, the toric lens 313 is an aspheric lens, and is relatively near the photosensitive drum, and accurately reproduces a laser spot shape on the photosensitive drum.

In the above-described conventional full-color image forming apparatus having a plurality of image carriers, the position of an image formed on each image carrier is detected, and finally, a plurality of color images are formed on a transfer material. Means for correcting the writing start position of the image so that the image position matches is used.

Conventionally, in an electrophotographic image forming apparatus, a polygon mirror is rotated at a higher speed as a means for improving a scanning speed of a laser scanner and improving a printing speed. As such, a motor having a well-known pneumatic bearing is used. This pneumatic motor is not a scale that enables high-speed rotation, but always rotates due to the excellent durability of the bearing portion.

FIG. 11 is a schematic structural diagram of a conventional image forming apparatus. This image forming apparatus is a tandem type full-color image forming apparatus, and includes a plurality of image carriers 202 (20).
2a to 202d), a plurality of charging means 203 (203a to 203d) for charging the image carrier respectively, and an electrostatic latent image formed on the charged surface of each image carrier is developed with a plurality of toners, and each color is developed. A plurality of developing means 205 (205a to 205d) for forming a plurality of toner images, and a plurality of transfer means 206 (2) for sequentially transferring the plurality of color toner images to a transfer object.
06a to 206d).

Pa, Pb, Pc and Pd are first to fourth four image forming means for forming images of different colors. Each of these image forming units includes a photosensitive drum 2a to 2d as an image carrier, and charging units 203a to 2d.
03d, image exposure means (laser scanning unit) 201a-
201d, cleaning means 204 (204a, 204
b, 204c, 204d), developing means 205a to 205
d.

The first image forming unit Pd is formed of yellow toner, the second image forming unit Pc is formed of magenta toner, the third image forming unit Pb is formed of cyan toner, and the fourth image forming unit Pd is formed of cyan toner. Performs image formation with black toner.

Here, the first to fourth image forming means P
The basic configuration of d, Pc, Pb, and Pa is the same as that of the image forming station in FIG.

First to fourth image forming means Pd, P
In c, Pb, and Pa, a laser beam modulated according to image data from a host such as a personal computer is irradiated from the laser scanning unit 201 onto the surface of the photosensitive drum 202 uniformly charged by each charging unit 203, A desired electrostatic latent image is obtained for each color. This latent image is reversely developed at a development site by a developing unit 205 which is a developing device containing toner of each color disposed opposite thereto and is visualized as a toner image.

First, the first (first color) image forming unit P
In step d, a yellow toner image is formed on the photosensitive drum 202d. During this time, the recording paper S is fed from the transfer material storage unit 70 such as a cassette by a paper feeding means such as a paper feed roller as a transfer material. Then, the sheet is conveyed to the pair of registration rollers 71 and 72. The recording paper S is a pair of registration rollers 71, 7
2, the driving roller 263 and the driven roller 262
Is attracted and conveyed to the electrostatic transport belt 261 suspended at a predetermined timing by an attraction roller (not shown), and is transferred at a nip portion with the transfer roller 261.

Next, the second (second color), third (third color), and fourth (fourth color) image forming means Pc, Pb, P
3A, the toner image of each color of magenta, cyan, and black is formed through each of the photosensitive drums 202 through the same process.
Multiple transfer is sequentially performed on the same recording paper S from c, 202b, and 202a to form a color toner image.

The color toner image transferred onto the recording paper S is fused and fixed by fixing means 74 such as a fixing device, is permanently fixed on the recording paper S, and is discharged face-up from a discharge section to a discharge tray. The image is discharged to 77 and a desired color print image is obtained.

[0029]

In the full-color image forming apparatus shown in FIG. 12, since the components from the polygon mirror to the photosensitive drum are arranged on a vertical line, the total length of the laser scanning unit becomes longer, If the capacity of the medicine container is sufficiently provided, it is difficult to provide the frame of the laser scanning unit with sufficient rigidity because the thickness is limited. Further, in a copying machine, the engine portion of the image forming apparatus main body becomes larger in the height direction due to the longer overall length of the laser scanning unit, so that the operator (operator) can smoothly operate the original on the original reader. As a result, the space for accommodating the transfer material is reduced.

When a vertical laser scanning unit formed on a vertical plane is fixed to the image forming apparatus main body, position adjustment for performing initial adjustment of a laser irradiation position of the laser scanning unit (irradiation position initial adjustment). However, there is a drawback that means for stabilizing a fixed hand that does not affect the image such as banding due to vibration of an optical component and that can easily perform all of the easy-to-mount operations are not provided.

Further, in the conventional image forming apparatus, there is no manual operation for easily correcting the bending of the scanning line where each laser scanning unit scans the photosensitive drum surface with a simple configuration.

Further, since the motor for driving the polygon mirror is arranged so that the rotation of the motor is horizontal, when a motor having a dynamic pressure type bearing using air or liquid is used, the gap between the rotor and the stator is reduced. There is a disadvantage that the jitter performance is deteriorated due to the large non-uniformity of the rotor, or the specific stator portion and the rotor portion are partially worn out in a low rotation speed range at the time of starting and stopping, so that sufficient durability cannot be obtained. Was.

Further, as a safety measure at the time of service maintenance, a safety means for preventing laser light from being emitted from the laser scanning unit has not been provided.

An object of the present invention is to provide a scanning optical apparatus which can be efficiently housed in an image forming apparatus while reducing the size of the entire apparatus.

Another object of the present invention is to provide a scanning optical device capable of achieving at least one of the following items and an image forming apparatus using the same. The image forming apparatus including the light beam scanning unit can be effectively reduced in size, and the initial adjustment of the irradiation position is easy. -The scanning optical device can be stably fixed when mounted on the image forming apparatus, and the attaching / detaching operation is easy. The bending of the scanning line on the photosensitive surface when scanning the photosensitive drum surface for each operation optical device can be corrected with a simple configuration.・ Because the polygon mirror motor having the dynamic pressure type rotation axis can be used stably, it is possible to increase the scanning speed of the light beam, and to switch whether or not to emit the light beam from the light beam unit with a simple configuration. Means are possible.

[0036]

According to a first aspect of the present invention, there is provided a scanning optical apparatus, comprising: a light source means; a first optical member for causing a light beam from the light source means to enter a deflecting means; A reflecting means for reflecting and deflecting the optical path of the light beam by approximately 90 degrees; and a second optical member for causing the light beam from the reflecting means to be incident on the surface of the image carrier. In the scanning optical apparatus, the reflecting means and the second optical member are provided with adjusting means for adjusting their postures, and the deflecting means and the first storing part in which the first optical member is stored; The reflection means and the second storage section in which the second optical member is stored are L-shaped.

According to a second aspect of the present invention, in the first aspect, the first optical member has a toric lens, and the second optical member has a diffractive optical element.

According to a third aspect of the present invention, in the first aspect of the present invention, the second storage portion is provided with a light blocking means for blocking the light beam from the reflecting means by moving the reflecting means. And

According to a fourth aspect of the present invention, there is provided a scanning optical apparatus, comprising: a light source means; a deflecting means for reflecting and deflecting a light beam from the light source means; and two or more imaging means for imaging the light beam deflected by the deflecting means. Means, a reflecting mirror provided between the two or more imaging means, and a housing means for integrally housing the reflecting mirrors, and the housing means substantially applies a light beam between the deflecting means and the reflecting mirror. The present invention is characterized in that a parallel first accommodating portion and a second accommodating portion substantially parallel to a light beam between the reflection mirror and the image carrier are formed in an L shape.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, at least one of the two or more imaging means is a diffractive optical element, and the position of the diffractive optical element is displaced so that the image carrier can be moved. It is characterized in that the irradiation position of the light beam on the surface can be adjusted.

According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the reflection mirror can adjust the position of the reflection surface.

According to a seventh aspect of the present invention, in the fourth aspect of the present invention, the deflecting means has a rotary polygon mirror and a motor having a dynamic pressure type bearing for rotating the rotary polygon mirror.

The image forming apparatus according to the invention of claim 8 is the first embodiment.
7. An electrostatic image is formed on the surface of the image bearing member by using the scanning optical unit according to any one of items 1 to 7.

According to a ninth aspect of the present invention, there is provided a color image forming apparatus comprising a plurality of the image forming apparatuses of the eighth aspect, wherein the plurality of image forming apparatuses form images of different color lights, respectively, and A color image is formed from an image formed by the apparatus.

In the multiplex image forming apparatus according to the tenth aspect,
In a multiplex image forming apparatus having a plurality of image carriers and a scanning optical device corresponding to each of the plurality of image carriers and forming a latent image on the surface of the image carrier by deflecting and scanning a light beam. Each scanning optical device comprises a light source means, a deflecting means for reflecting and deflecting a light beam from the light source means, two or more image forming means for forming an image of the light beam deflected by the deflecting means, and the two or more image forming means. A reflection mirror provided between the image means, and a storage means for integrally storing the reflection mirror, the storage means being a first storage part substantially parallel to a light beam between the deflecting means and the reflection mirror; The second housing portion substantially parallel to the light beam between the reflection mirror and the image carrier is configured in an L-shape.

According to an eleventh aspect, in the tenth aspect, at least one of the second accommodating portions of the L-shaped accommodating means is disposed between the developer containers of the plurality of developing means. It is characterized by.

According to a twelfth aspect of the present invention, in the tenth aspect, the scanning optical device is substantially parallel to the first housing portion.
It is characterized by being provided on a common or divided frame.

According to a thirteenth aspect, in the tenth aspect, the position of the reflection mirror is adjustable.

According to a fourteenth aspect, in the tenth aspect, the imaging means provided in the second housing is a diffractive optical element, and by displacing the position of the diffractive optical element, an image carrier is formed. It is characterized in that the light beam irradiation position on the surface can be adjusted.

According to a fifteenth aspect of the present invention, in the tenth aspect of the present invention, the scanning optical device is provided so that the first housing portion is horizontal.

According to a sixteenth aspect of the present invention, in any one of the tenth to fifteenth aspects, the deflecting means has a rotary polygon mirror and a motor having a dynamic pressure type bearing for rotating the rotary polygon mirror. Features.

A seventeenth aspect of the present invention is the invention according to any one of the tenth to sixteenth aspects, further comprising means for switching whether to emit a light beam from the scanning optical device by rotating the reflection mirror. I have.

[0053]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of Embodiment 1 when an image forming apparatus (multiplex image forming apparatus) of the present invention is applied to a digital full-color copying machine (color image forming apparatus), and FIG. FIG. 2 is a schematic diagram of a laser scanning unit in the digital full-color copying machine shown in FIG.

First, a copy operation (copy operation) of the digital full-color copying machine of the present embodiment will be described with reference to FIG. In the figure, reference numeral 8 denotes a document reading unit which converts the document placed on the mirror base and fixed by the pressure plate 86 into mirrors 85, 84, 8;
3 through a reading lens 82 and a line sensor 81
The image information on the document is read by the line sensor 81.

A signal from the line sensor 81 is input to a laser scanning unit, which will be described later, and performs light modulation of laser light output from the laser scanning unit based on the signal. Reference numeral 10 denotes a full-color image forming unit. In the full-color image forming section 10, four image forming stations Pa to Pd for forming image information for each color light are arranged, and each image forming station is a photosensitive drum 2 (2) as an image carrier.
a, 2b, 2c, 2d). Each of the image stations Pa to Pd is integrally formed in the form of a process cartridge, and is detachably attached to the apparatus main body.

A dedicated charging means 3 is provided around the photosensitive drum 2.
(3a, 3b, 3c, 3d), a laser scanning unit 1 (1a, 1b, 1c, 1d) for irradiating the photosensitive drum with light corresponding to image information for each color light, and a developing unit 5 (5a,
5b, 5c, 5d), drum cleaning means 4 (4
a, 4b, 4c, 4d), transfer means 6 (6a, 6b, 6
c, 6d) are arranged respectively. Also, 51 (5
Reference numerals 1a to 51d) denote developer containers corresponding to the developing means 5a to 5d, respectively, which are provided immediately below the horizontal portions of the laser scanning units (scanning optical devices) 1a to 1d and arranged in line with the vertical portions. The developer is supplied by attaching and detaching a cylindrical developer cartridge. Here, the image forming stations Pa, Pb, Pc, and Pd form a cyan image, a magenta image, a yellow image, and a black image, respectively.

On the other hand, each of the image forming stations Pa to Pd
, An endless belt-shaped intermediate transfer belt 61 is disposed below the photosensitive drums 2a, 2b, 2c, and 2d.
The intermediate transfer belt 61 is stretched around a driving roller 62 and driven rollers 63 and 65, and further provided with a cleaning unit 64 for cleaning the surface thereof.

In this configuration, first, the charging means 3a of the first image forming station Pa, the laser scanning unit 1
a latent image of the cyan component of the image information is formed on the photosensitive drum 2a by a known electrophotographic process means such as exposure by a, and the latent image is formed as a cyan toner image by a developing agent having a cyan toner in a developing means 5a. The image is visualized and the cyan toner image is transferred to the surface of the intermediate transfer belt 61 by the transfer unit 6a.

On the other hand, while the cyan toner image is being transferred onto the intermediate transfer belt 61, a magenta component color latent image is formed on the photosensitive drum 2b in the second image forming station Pb, and then the developing means 5b To form a toner image with magenta toner, and the first image forming station P
a transfer means 6b
, The magenta toner image is transferred with high accuracy.

Thereafter, image formation is performed on the yellow image and the black image in the same manner, and when the superposition of the four color toner images on the intermediate transfer belt 61 is completed, the four color toner image on the intermediate transfer belt 61 becomes At the secondary transfer roller 66,
Manual paper cassette (multi-purpose tray) 70
The sheet is re-transferred (secondarily transferred) onto the sheet S conveyed at the same timing by the sheet feeding roller 71, the conveying roller 72, and the registration roller 73. Then, the toner image transferred by the fixing roller pair 74 is heated and fixed to the sheet material S on which the secondary transfer has been completed, and a full-color image is obtained on the sheet material S.

Each of the photosensitive drums 2 whose transfer has been completed
In a to 2d, residual toner is removed from each drum by cleaning means 4a to 4d to prepare for the subsequent image formation. Reference numerals 78 and 79 denote paper cassettes.

Reference numeral 69 denotes an image position reading detection unit for detecting the position information of the intermediate transfer belt 61. 69A and 69 are located at three positions on the back side, the center, and the front side of the intermediate transfer belt, respectively.
Three image reading units B and 69C having the same configuration are arranged. FIG. 5 is a schematic diagram of the configuration of the image position reading detection unit 69. In FIG. 5, the image reading detection unit 69A will be described as an example. First, the optical configuration illuminates infrared light from above with a lamp 61-1A on the surface of a black intermediate transfer belt 61 that moves at a constant speed in a direction perpendicular to the paper surface, and the reflected light is other than infrared light. The filter film to be cut is formed on the line CCD 69-6 by the imaging lens 69-4 through the dustproof glass 69-3 provided on the surface thereof. The resolution of the image reading detection unit on the intermediate transfer belt 61 of this embodiment is 10 μm in the CCD line direction, and the reading period for each line is 0.1 ms for a moving speed of the intermediate transfer belt 61 of 100 mm / s. By doing so, an image on the intermediate transfer belt can be read with a resolution of 10 μm even in the moving direction of the intermediate transfer belt 61.

Before the image forming apparatus forms an image, an image is formed as a “+” mark at a predetermined target position on the intermediate transfer belt 61 at each image forming station, and the image position of the “+” mark is determined. Image position reading detection unit 69
, And calculates by the CPU to detect the amount of image misalignment of each parameter on the intermediate transfer belt at the image forming position of the image formed by each image forming station, and automatically corrects it by the correction means described later. .

Here, the image position reading detection unit 69 used in the present embodiment can measure the following five parameters shown in FIGS. 14A to 14E.

(A-1) Vertical margin deviation (A-2) Left and right margin deviation (A-3) Inclination deviation (A-4) Magnification deviation (A-5) Curving of scanning line Next, the laser scanning unit shown in FIG. Details of 1a to 1d will be described with reference to FIG. Laser scanning unit 1
a to 1d all have the same configuration.

FIG. 2A is a plan view of an essential part when one laser scanning unit is taken as an example, and FIGS. 2B and 2C are views from the directions of arrows A and B in FIG. It is a principal part side view at the time of seeing. Reference numeral 19 denotes a light source unit, which has a laser light emitting diode 19-1 and a driving electric board 19-2, a collimator lens barrel 19-3, and an aperture (not shown), and emits parallel laser light. . Reference numeral 18 denotes a cylinder lens having a refractive power in a direction perpendicular to the paper surface.
Numeral 11 denotes a deflecting means for deflecting and scanning the laser light, which has a polygon mirror and its motor unit. Reference numerals 12 and 13 denote a toric lens and a diffractive optical element that form an image of the laser beam on the photosensitive drum 2 at a predetermined spot diameter, and constitute one element of a scanning optical system. 17 is a reflection mirror and 2
Numeral 0 denotes a dust-proof glass held so as to be able to slide in and out of case 90.

As shown in FIG. 4, the diffractive optical element 13 is formed by applying an ultraviolet curable resin to the surface of a base material 13-1 and forming a resin portion having a grating thickness such that the diffraction efficiency of the primary diffracted light at a wavelength of 530 nm is 100%. The layer 13-2 of t is formed. Note that the diffractive optical element 13 may have a multilayer structure in which a plurality of diffraction gratings are stacked. 16 is a beam detector (B
D), and the laser beam writing timing (synchronization signal) for each line is taken on the photosensitive drum. 14 is BD1
6 is a reflecting mirror for reflecting a light beam, 15 is a BD 14
This is an imaging lens for condensing a light beam on the lens. The diffractive optical element 13 and the reflecting mirror 17 are supported so as to be rotatable in the directions P and R indicated by arrows, respectively. Regarding the rotation of the reflection mirror 17, the reflection mirror 17 is rotated by an actuator whose configuration will be described later, in conjunction with the front door of the copying machine main body (not shown) and the opening / closing switch means thereof. The laser beam is irradiated entirely to the light shielding means 90-1 composed of convex portions provided widely on the 90, so that the laser light is not emitted from the scanner case 90.

The laser scanning units 1a to 1d are respectively mounted from above on a horizontal surface of the main body of the image forming apparatus or on a stay having a slight inclination, from the light source unit 19 to the reflection mirror 17 including the polygon mirror 11. Are arranged horizontally or with a slight inclination. When the laser scanning units 1a to 1d are mounted on the stay, the corresponding photosensitive drums 2a to 2d are mounted.
In order to initially adjust the irradiation position for 2d to a predetermined position, the position is changed on the stay and fastened and fixed with four screws (not shown).

The correction means for adjusting the image position is shown in FIG.
4 (A) to 4 (E), the vertical margin shift and the left and right margin shift are performed by changing the laser writing timing by a required amount with respect to the YMC image position with respect to the black Bk image position. Do
The magnification shift is performed by changing the modulation frequency of the laser diode 19 by a predetermined amount. Adjustment of these three items can be made relatively easily by changing the electrical synchronization timing and frequency. However, for the remaining inclination shift and scanning line bending, a large-scale and high-cost configuration is required to adjust the image signal similarly by changing the image signal. Therefore, these remaining adjustment items are performed by an optical method as described later. The outline is described below. First, as for the adjusting means, regarding the inclination shift, the diffractive optical element 1 shown in FIG.
2 is adjusted (corrected) by rotating it in the P direction by the laminated piezoelectric actuator 13-1 about the rotation axis 13-3, and the scanning line bending is also reflected by the reflection mirror 1 shown in FIG.
7, the reflecting mirror 17 is rotated and displaced by a predetermined amount in the R direction by a linear actuator including a pulse motor 17-1 and a feed screw 17-2 provided at one of the support points of the diffractive optical element 13. Adjustment (correction) is performed by adjusting the incident angle.

Here, the adjustment (correction) of the inclination shift will be further described with reference to FIGS. 6 (A) and 6 (B). FIG. 2A shows the main optical components of the configuration of the laser scanning unit and the photosensitive drum shown in FIG. 2 developed on one plane, and the same elements are denoted by the same reference numerals.

In the figure, as described above, the light beam that scans on the surface of the photosensitive drum 2 exits the light source unit 19, passes through the cylindrical lens 18 having a predetermined refractive power in the sub-scanning direction, and passes through the polarization plane of the rotating polygon mirror 11. The light is condensed linearly, is deflected and reflected by the rotating polygon mirror 11, passes through the toric lens 12, the reflection mirror 17, and the diffractive optical element 13, and irradiates the surface of the photosensitive drum 2. L is an optical axis, which corresponds to the scanning central axis and the optical axis of the toric lens 12.

In the scanning optical device of this embodiment, the light beam scanned on the photosensitive drum surface 2 is rotated by rotating (rotating) in the direction of arrow G about the optical axis of the diffractive optical element 13 substantially at the center. As shown by a dotted line H in FIG.

In the scanning optical device of this embodiment, by rotating the diffractive optical element in the direction of arrow G in the figure for 10 minutes, the right end of the scanning line on the surface of the photosensitive drum as shown in FIG. 0.3 mm higher, and the left end lowers by approximately 0.3 mm.

Since the amount of rotation (the amount of rotational movement) of the diffractive optical element 13 and the amount of inclination of the scanning line are substantially proportional to each other, the amount of rotation of the diffractive optical element 13 is adjusted by a necessary amount to correct the inclination deviation. , The inclination of the scanning line can be adjusted. That is, in the present embodiment, the inclination of the scanning line can be adjusted by rotating the diffractive optical element by a predetermined amount about the optical axis on the basis of the signal (detection result) obtained by the detection means 69 described above. .

Similarly, the adjustment (correction) of the scanning line bending will be further described with reference to FIGS. 7 (A), 7 (B) and 7 (C).

In the scanning optical device of this embodiment, the angle of the reflecting surface of the reflecting mirror 17 is rotated (rotated) in the R direction about the optical axis (corresponding to the operation center axis and the optical axis of the toric lens) L. By changing the angle of the optical axis L incident on the diffractive optical element, the light beam scanned on the photosensitive drum surface 2 is bent and scanned as shown by a dotted line J in FIG.

In the scanning optical device according to the present embodiment, the optical axis L incident on the diffractive optical element is set in the direction of arrow R in FIG.
By turning, the scanning line on the surface of the photosensitive drum bends so that the left and right ends thereof are approximately 0.2 mm higher as shown in FIG.

Since the angle of the incident light of the diffractive optical element is substantially proportional to the amount of bending of the scanning line, in the present embodiment, the angle of the incident light to the diffractive optical element is rotated by an amount necessary to correct the bending. That is, the bending of the scanning line is adjusted by rotating the reflection mirror 17. That is, in the present embodiment, the inclination of the scanning line is adjusted by rotating the reflection surface angle of the reflection mirror 17 by a predetermined amount around the optical axis based on the detection result by the above-described detection means 69 in the same manner as the inclination shift adjustment. are doing.

When the tilt is adjusted in the present embodiment, the top margin in FIG. 14A and the magnification in FIG. 14C slightly vary according to the rotation of the mirror. It is easily predicted and corrected by changing the timing and frequency. Furthermore, since the present configuration provides the tilt and bending adjustment means on separate optical elements,
By avoiding the complication of the adjustment mechanism, the optical component for adjustment can be stably supported.

Next, the configuration of the deflecting means polygon motor 11 used in this embodiment will be described. FIG. 3 shows a schematic diagram of the deflection means 11. In FIG. 3, reference numeral 11-2 denotes a shaft, which is fixed to the housing 11-11, and has a spiral groove formed on the surface thereof. Reference numeral 11-3 denotes a rotor sleeve to which the polygon mirror 11-1 is fixed by fixing screws 11-6. An air dynamic pressure bearing is formed by forming a minute gap between the shaft portion 11-2 and the rotor sleeve 11-3. And polygon mirror 1
1-1 is driven to rotate by a rotor magnet 11-4 and a stator coil unit 11-12. In order to improve the rotation accuracy and reduce the generated vibration during this rotation, the balance of the upper and lower surfaces of the rotating part is balanced. Balance correction grooves 11-7 and 11-8 for adding a weight to be corrected are provided.
Further, reference numerals 11-9 and 11-10 denote opposing magnet portions for floating the rotor. The polygon motor 11 used in the present embodiment has the above-described configuration, and is capable of low-vibration and constantly rotating at a high speed of about 24000 rpm.

[0081]

[Other Embodiments] Hereinafter, a second embodiment of the present invention will be described.

FIG. 8 is a schematic view of a laser scanning unit according to the second embodiment. FIG. 9 is a schematic diagram of an image position reading detection unit according to the second embodiment. FIG. 10 is a schematic diagram of a full-color printer equipped with the image forming apparatus of the second embodiment.

In Embodiment 2, in FIG. 8, a reflection mirror 117 is provided between the cylinder lens 112 and the toric lens 113, and the reflection mirror 117 is supported on a linear movable base 117-2. The position of the linear movable base 117-2 is controlled in the direction of T by an actuator 117-1 that makes the rotary motion of the pulse motor linear by a feed screw. Here, in the same manner as in the first embodiment, when adjusting the image position, the position of the reflecting surface of the reflecting mirror 117 is changed in the T direction with respect to the scanning line bending in FIG. The correction is performed by moving the laser beam position in the T direction in parallel. Further, in the second embodiment, for example, a transparent intermediate transfer belt made of PET is used, so that the transmitted light for reading the position of the intermediate transfer belt 306 by the transmitted light as in the illumination lamp 369-1 and the detection unit 369 in FIG. Uses read-only means. The polygon motor (deflecting means) 1 shown in FIG.
For example, a motor unit having a contact-type bearing such as a ball bearing is used for the lens unit 11. In this embodiment, the polygon mirror is arranged so as to be horizontal, but the L-shaped laser scanning unit of the second embodiment is used. 190 may arrange the polygon motor at any angle.

As described above, according to each embodiment of the present invention, a reflecting mirror is provided between two or more image forming means between the deflecting scanning means and the image carrier, and an L-shape for accommodating them is provided. The provision of the storage means makes it possible to reduce the size of the image forming unit effectively and efficiently.

Further, by providing each light beam scanning unit on a common or divided frame substantially perpendicular to the optical axis of the emitted light beam, initial adjustment of the irradiation position is easy and the unit can be stabilized. Can be fixed at the same time, and the attachment / detachment operation is easy.

Further, at least one of the two or more imaging means in the light beam scanning unit is a diffractive optical element, and by displacing the position of the diffractive optical element, the light beam on the surface of the image carrier is displaced. The irradiation position can be adjusted.

Furthermore, by adjusting the position of the reflecting surface in at least one direction of the reflecting mirror in the light beam scanning unit, it is possible to adjust the scanning line bending with a simple configuration.

Further, the light beam scanning unit uses a motor having a dynamic pressure type bearing for rotating and driving a rotating polygon mirror, on a frame of the image forming apparatus, a housing case is provided so that the deflecting means is horizontal. By doing so, it is possible to improve the print speed and shorten the first copy time. And the like.

In the first and second embodiments, only the case using the intermediate transfer belt has been described. However, the present invention is not limited to this, and the image is directly formed on the sheet material without using the intermediate transfer belt. It may be an image forming apparatus for forming, or an image forming apparatus having a plurality of photosensitive members and a plurality of light beam scanning means.

Further, only the apparatus having the image position correcting means has been described, but the present invention is not limited to this.

The image position reading detection unit (image position sensor) has been described as a means for reading the reflected light or transmitted light of the toner image on the belt by the line CCD using the illuminating means, but the detecting method is not limited to this. Instead, for example, a device using an area CCD sensor or a device in each image forming station that directly measures the amount of change in laser light may be used.

The means for correcting the image position deviation is not limited to the one described in the above embodiment, and the number of correction items provided with the correcting means may be any number in the above embodiment.

Further, although all the laser scanning units in the same image forming apparatus are shown as having the same configuration, the present invention is not limited to this. A configuration without the image position correcting means in the laser scanning unit may be used.

Although only the automatic adjustment means using an actuator has been described as the adjustment means for the reflection mirror, the invention is not limited to this. For example, an adjustment screw without an actuator may be used.

Although the air dynamic pressure bearing type polygon motor is shown only with the polygon mirror arranged horizontally, the polygon motor is arranged at an angle as long as the rotation performance and durability are not impaired. Is also good.

[0096]

According to the present invention, it is possible to achieve a scanning optical device that can be efficiently housed in an image forming apparatus while reducing the size of the entire apparatus.

In addition, the present invention has the following advantages. The image forming apparatus including the light beam scanning unit can be effectively reduced in size, and the initial adjustment of the irradiation position is easy. -The scanning optical device can be stably fixed when mounted on the image forming apparatus, and the attaching / detaching operation is easy. The bending of the scanning line on the photosensitive surface when scanning on the surface of the photosensitive drum for each scanning optical device can be corrected with a simple configuration. .Stable use of a polygon mirror motor having a dynamic pressure type rotation axis enables the scanning speed of the light beam to be increased, and means for switching whether or not to emit the light beam from the light beam unit with a simple configuration. Is possible. Among them, it is possible to obtain a scanning optical device capable of achieving one or more items and an image forming apparatus using the same.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a digital full-color copying machine showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a laser scanning unit according to the first embodiment.

FIG. 3 is a schematic diagram of a polygon motor according to the first embodiment.

FIG. 4 is a schematic diagram of a diffractive optical element according to the first embodiment.

FIG. 5 is a schematic diagram of an image position reading device according to the first embodiment.

FIG. 6 is an explanatory diagram relating to a scanning line inclination shift correcting unit according to the first embodiment.

FIG. 7 is an explanatory diagram relating to a scanning line bending correcting unit according to the first embodiment.

FIG. 8 is a schematic diagram of a laser scanning unit according to a second embodiment of the present invention.

FIG. 9 is a schematic diagram of an image position reading device according to a second embodiment.

FIG. 10 is a schematic view of a full-color printer showing a second embodiment.

FIG. 11 is a schematic diagram of a conventional digital full-color copying machine.

FIG. 12 is a schematic diagram of a conventional digital full-color copying machine.

FIG. 13 is a schematic diagram of a conventional laser scanning unit.

FIG. 14 is a diagram showing image displacement parameters.

[Explanation of symbols]

8 Document reading unit 1 (1a, 1b, 1c, 1d) Laser scanning unit 2 (2a, 2b, 2c, 2d) Photosensitive drum 3 (3a, 3b, 3c, 3d) Charging means 4 (4a, 4b, 4c, 4d) Drum cleaning unit 6 (6a, 6b, 6c, 6d) Transfer unit 10 Full-color image forming unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/113 H04N 1/04 104A F-term (Reference) 2C362 AA47 BA08 BA10 BA51 BA82 BA84 BA85 BA86 BA87 BA90 DA02 DA04 DA06 DA28 2H045 AA24 BA22 BA34 CA02 CA33 CA67 DA02 DA04 DA41 2H087 KA19 LA22 NA09 PA01 PA02 PA17 PB01 PB02 RA07 RA08 RA42 RA46 5C072 AA03 DA02 DA04 DA20 DA21 DA23 HA09 HA13 JA07 XA05

Claims (17)

[Claims] 1. A light source means, a first optical member for causing a light beam from the light source means to enter a deflecting means, a reflecting means for reflecting and deflecting an optical path of a light beam reflected and deflected by the deflecting means by approximately 90 degrees, A second optical member for causing a light beam from the reflecting means to be incident on the surface of the image carrier; and a scanning optical device for optically scanning the surface of the image carrier by rotating the deflecting means. Are provided with adjusting means for adjusting their postures, a first storage section in which the deflecting means and the first optical member are stored, and a second storage section in which the reflecting means and the second optical member are stored. A scanning optical device characterized in that the portions are L-shaped. 2. The scanning optical apparatus according to claim 1, wherein said first optical member has a toric lens, and said second optical member has a diffractive optical element. 3. The scanning optical apparatus according to claim 1, wherein said second storage section is provided with a light blocking means for blocking a light beam from said reflecting means by moving said reflecting means. 4. A light source means, a deflecting means for reflecting and deflecting a light beam from the light source means, two or more image forming means for forming an image of the light beam deflected by the deflecting means, and the two or more image forming means. A reflection mirror provided between the image means, and a storage means for integrally storing the reflection mirror and the storage means, the storage means being a first storage part substantially parallel to the light beam between the deflecting means and the reflection mirror; A scanning optical device, wherein a second housing portion substantially parallel to a light beam between a reflection mirror and an image carrier is formed in an L shape. 5. At least one of said two or more imaging means is a diffractive optical element, and the position of the diffractive optical element is displaced to adjust the irradiation position of the light beam on the surface of the image carrier. 5. The scanning optical device according to claim 4, wherein the scanning optical device is enabled. 6. A scanning optical apparatus according to claim 4, wherein said reflection mirror is capable of adjusting a position of a reflection surface. 7. The scanning optical apparatus according to claim 4, wherein said deflecting means includes a rotary polygon mirror and a motor having a dynamic pressure bearing for driving the rotary polygon mirror. 8. An image forming apparatus, wherein an electrostatic image is formed on the surface of an image carrier by using the scanning optical means according to claim 1. 9. A plurality of image forming apparatuses according to claim 8, wherein the plurality of image forming apparatuses form images of different color light, respectively, and a color image is formed from the images formed by the plurality of image forming apparatuses. A color image forming apparatus for forming an image. 10. An image processing apparatus comprising: a plurality of image carriers; and a scanning optical device corresponding to each of the plurality of image carriers, and deflecting and scanning a light beam to form a latent image on the surface of the image carrier. In the multiplex image forming apparatus, each scanning optical device includes a light source unit, a deflecting unit that reflects and deflects a light beam from the light source unit, two or more imaging units that form an image of the light beam deflected by the deflecting unit, A reflecting mirror provided between the two or more imaging means, and a housing means for integrally housing the reflecting mirrors, the housing means comprising a first mirror substantially parallel to a light beam between the deflecting means and the reflecting mirror; And a second storage section substantially parallel to the light beam between the reflection mirror and the image carrier is formed in an L-shape. 11. The multiple image forming apparatus according to claim 10, wherein at least one of said second storage portions of said L-shaped storage means is disposed between developer containers of a plurality of developing means. apparatus. 12. The multiplex image forming apparatus according to claim 10, wherein said scanning optical device is provided on a common or divided frame substantially parallel to said first storage section. 13. The multiple image forming apparatus according to claim 10, wherein the position of the reflection surface of the reflection mirror is adjustable. 14. An image forming means provided in said second accommodating portion is a diffractive optical element, and the position of the light beam on the surface of the image carrier can be adjusted by displacing the position of the diffractive optical element. 11. The multiple image forming apparatus according to claim 10, wherein: 15. The multiplex image forming apparatus according to claim 10, wherein said scanning optical device is provided so that said first housing portion is horizontal. 16. The multiple image forming apparatus according to claim 10, wherein said deflecting means includes a rotary polygon mirror and a motor having a dynamic pressure bearing for driving the rotary polygon mirror. . 17. The multiple image forming apparatus according to claim 10, further comprising means for switching whether to emit a light beam from said scanning optical device by rotating said reflection mirror.