JP3468057B2 - Multiple image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiple image forming apparatus capable of forming a composite image by superimposing image information on a transfer material using an electrophotographic method or the like.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus adopting an electrophotographic system, an electrophotographic photosensitive member as an image bearing member is charged by a charger, and the photosensitive member is irradiated with light according to image information so as to be latent. An image is formed, and the latent image is developed by a developing device and transferred to a sheet material or the like to form the image.

On the other hand, a plurality of image carriers for each of these image forming processes are provided in accordance with colorization of images, and each color image of a cyan image, a magenta image, a yellow image, and preferably a black image is carried. There has also been proposed a tandem-type image forming apparatus that forms a full-color image by forming the image on a body and transferring the color images on a sheet material at the transfer position of each image carrier.

Since such a tandem type multiple image forming apparatus has an image forming section for each color, it is advantageous for speeding up.

However, there is a problem in how to perform good registration (registration) of images formed by different image forming units. This is because the deviation of the image forming positions of the four colors transferred to the sheet material eventually appears as a color deviation or a change in color tone.

By the way, as the types of positional deviation of the transfer image, as shown in FIGS. 10A, 10B, 10C and 10D, the scanning line writing direction (see FIG. Positional deviation (top margin) in the direction of the arrow A (see FIG. 10)
(A)), scanning direction (arrow B orthogonal to arrow A in the figure)
Misalignment (left margin) (Fig. 10)
(B)), displacement in the diagonal direction (FIG. 10 (c)), and displacement in magnification error (FIG. 10 (d)), and in reality, the above four types of displacements are superposed.

The main cause of the image shift is shown in FIG.
In the case of the top margin of (a), there is a deviation in the image writing timing of each image forming station.
In the case of the left margin of (b), it is a deviation of the writing timing of each image of each image forming station, that is, the scanning start timing in one scanning line.

In the case of the tilt deviation in the oblique direction in FIG. 10C, the deviation is due to the mounting angle of the scanning optical system or the rotation axis of the photosensitive drum, and in the case due to the magnification error in FIG. 10D. This is due to the deviation of the scanning line length due to the error in the optical path length from the scanning optical system of each image forming station to the photosensitive drum.

Therefore, in order to eliminate the above four types of deviations,
First, with respect to the top margin and the left margin, the scanning timing of each color is adjusted to correct the deviation amount. As for the magnification error deviation and the inclination deviation, the three folding mirrors 1 in the optical path of each station shown in FIG.
Of the 01, 102, and 105, a pair of substantially C-shaped mirrors 101 and 102, whose mirror surfaces are held at right angles, are used as actuators in the arrow M direction and the arrow N direction with respect to the apparatus body as shown in FIG. The amount of deviation can be corrected by adjusting each of 103 and 104 independently.

As an actuator for making these adjustments, a linear step actuator having a step motor, which is a drive source for linearly moving in stages, is used.

The above construction is extremely effective in preventing the positional deviation of the four colors.

[0012]

However, the above-mentioned conventional structure has a drawback that the structure for the magnification error and inclination deviation correcting means is complicated and that it is apt to vibrate due to the large number of parts. Therefore, the position of the laser beam irradiated on the photoconductor vibrates and appears as scanning unevenness, and the scanning unevenness appears as light and shade of the output image, and the image quality is significantly deteriorated.

The above-mentioned problems are very serious in forming a high quality image without color shift in a digital color multiplex image forming apparatus.

According to the present invention, the structure of the color misregistration correction means is simplified and the cost is reduced, and the color misregistration can be easily adjusted, and the misalignment of each pixel when the optical scanning images by a plurality of light beams are superposed. It is an object of the present invention to provide a multiplex image forming apparatus that eliminates the above.

[0015]

In order to solve the above problems, the present invention provides a plurality of photoconductors, an exposing means for irradiating each of the photoconductors with light to form a latent image, and a photoconductor. A plurality of developing means for visualizing the formed latent image and a transfer means for transferring the image visualized by the developing means to a transfer material are provided, and the visualized image is formed on each of the photoconductors. In a multiple image forming apparatus that sequentially superimposes on a transfer material to form a composite image, the exposure unit is arranged so that the exposure unit scans the photoconductor at a predetermined inclination with respect to a direction perpendicular to the transfer direction of the photoconductor. The photoconductor is arranged such that the direction perpendicular to the transfer direction of the photoconductor is positioned between the inclination of the scanning line by the exposure unit and the direction substantially perpendicular to the transfer direction of the transfer material. It is equipped with speed adjustment means to change each transfer speed. The distortion of the output image, which is not a rectangle but a parallelogram whose inside angle is not right angle due to the inclination of the line, is corrected at the time of transfer in the transfer area to the transfer material, and the output image becomes a rectangular image with an inside angle of almost right angle. The tilt deviation can be adjusted by changing the transfer speed of the photoconductor while keeping the same, the structure of the color deviation correcting unit can be simplified and the cost can be reduced, and the color deviation can be easily adjusted.
It is possible to obtain a multiple image forming apparatus in which the displacement of each pixel is eliminated when a plurality of light beams and light scanning images by a plurality of photoconductors are superposed.

Further, the inclination angle of the direction perpendicular to the transfer direction of the transfer material to the direction perpendicular to the transfer direction of the photoconductor is the inclination angle of the scanning line by the exposure means with respect to the direction perpendicular to the transfer direction of the transfer material. Since the output image is not a rectangle but a parallelogram whose interior angles are not right angles due to the inclination of the scanning line, the distortion of the image is accurately corrected when the image is transferred to the transfer material in the transfer area. , While keeping the output image as a rectangular image having a right angle inside angle, it is possible to adjust the tilt deviation by changing the transfer speed of the photoconductor, simplifying the structure of the color misregistration correction unit and reducing the cost, Further, the color misregistration can be easily adjusted, and the multiple image forming apparatus can be obtained in which the misalignment of each pixel is eliminated when the optical scanning images by the plural light beams and the plural photoconductors are superposed.

Further, since each photoconductor is rotated about a predetermined position in each photoconductor that is predetermined and an inclination angle is given to the photoconductor, an oblique direction can be obtained without increasing the machine size. Adjustment of the inclination deviation of the color misregistration can be performed, the structure of the color misregistration correction unit can be simplified and the cost can be reduced, and the color misregistration can be easily adjusted. In this case, it is possible to obtain a multiple image forming apparatus that eliminates the deviation of each pixel.

Further, since all the photoconductors are rotated about a predetermined point so that the photoconductors are inclined, the end portions in the direction perpendicular to the transfer direction of the plurality of photoconductors are formed. It can be arranged on a straight line, and tilt deviation can be adjusted while maintaining high accuracy when arranging a plurality of photoconductors, which simplifies and reduces the cost of the color misregistration correction unit, and further the color misregistration. It is possible to obtain a multiple image forming apparatus in which the adjustment can be easily performed and the displacement of each pixel is eliminated when the optical scanning images by the plurality of light beams and the plurality of photoconductors are superposed.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention comprises a plurality of photoconductors, exposure means for irradiating each of the photoconductors with light to form a latent image, and each of the photoconductors. And a transfer means for transferring the image visualized by the developing means onto a transfer material. The latent image formed on the photosensitive member is visualized on each of the photoconductors. In a multiplex image forming apparatus that sequentially superimposes the formed images on a transfer material to form a composite image, the exposure unit scans the photoconductor with a predetermined inclination with respect to a direction perpendicular to the transfer direction of the photoconductor. The exposing means is arranged so that the direction perpendicular to the transfer direction of the photoconductor is located between the inclination of the scanning line by the exposing means and the direction substantially perpendicular to the transfer direction of the transfer material. The speed adjusting hand for arranging the photoconductors and changing the transfer speed of each of the photoconductors. With this configuration, the distortion of the image in which the output image is not a rectangle but a parallelogram whose interior angle is not right angle due to the inclination of the scanning line is scanned in a direction perpendicular to the transfer direction of the photoconductor. By disposing the photoconductor so as to be positioned between the inclination of the line and the direction in which the transfer material is transported at a substantially right angle, the transfer image on the transfer material is corrected during transfer, and the output image has almost no internal angle. With the rectangular image kept at a right angle, the tilt deviation can be adjusted to change the transfer speed of the photoconductor.

According to a second aspect of the present invention, in the first aspect of the invention, an inclination angle of a direction perpendicular to a transfer direction of the transfer material and a direction perpendicular to the transfer direction of the transfer material is the exposure. The scanning line by the means has a configuration in which the inclination angle is approximately 1/2 of the direction orthogonal to the transfer material transfer direction. With this configuration, the output image is not rectangular but the interior angle is perpendicular due to the inclination of the scanning line. The parallel image is not distorted, and the image distortion occurs.The inclination angle of the direction perpendicular to the transfer material transfer direction is perpendicular to the photoconductor transfer direction. By setting the inclination angle to approximately 1/2 of the above direction, it is possible to accurately correct when transferring to the transfer material in the transfer area, and to adjust the inclination deviation while maintaining the output image as a rectangular image with a right angle inside. Change the transfer speed of the photoconductor Such an action can be performed in.

According to a third aspect of the present invention, in the first aspect of the invention, each of the photoconductors is rotated about a predetermined location in each of the photoconductors, which is predetermined, and the photoconductor is tilted. With this configuration, with this configuration,
Since the respective photoconductors rotate around the respective places where the photoconductors are arranged, there is an effect that the tilt deviation in the oblique direction can be adjusted without increasing the machine size.

According to a fourth aspect of the invention, in the invention according to the first aspect, all the photoconductors are rotated about a predetermined point as an axis to give an inclination angle to the photoconductors. With this configuration, it is possible to arrange the ends of the plurality of photoconductors in a direction perpendicular to the transfer direction on a straight line, and to keep the accuracy of the placement of the plurality of photoconductors with high accuracy while maintaining the inclination deviation. It has the effect that adjustment can be performed.

Embodiments of the present invention will be described below. FIG. 1 is a sectional view showing the arrangement of a multiple image forming apparatus using the multiple image forming apparatus according to the embodiment of the present invention, and FIG.
FIG. 3 is a state diagram of correction of color misregistration on the image bearing member using the multiplex image forming apparatus according to one embodiment of the present invention, and FIG. 3 is a color registration error of transfer area using the multiplex image forming apparatus according to one embodiment of the present invention. FIG. 4 is a correction state diagram, and FIG. 4 is a tilt angle correction output state diagram using the multiplex image forming apparatus according to one embodiment of the present invention.

First, FIG. 1 shows an embodiment of the present invention.
Will be explained. The image forming apparatus is provided with four image forming stations Pa, Pb, Pc and Pd. Each of the image forming stations Pa, Pb, Pc and Pd has a photoconductor drum 1a, 1b, 1c and 1d as an image bearing member, respectively. Have.

In addition, around it, a dedicated charging means 2a,
2b, 2c, 2d, exposure means 3 for irradiating the respective photosensitive drums 1a, 1b, 1c, 1d with light according to image information, developing means 4a, 4b, 4c, 4d, transfer means 5
a, 5b, 5c, 5d, cleaning means 6a, 6b,
6c and 6d are arranged respectively. Further, the exposure unit 3 is arranged in advance with a certain inclination with respect to the photosensitive drums 1a, 1b, 1c and 1d.

Here, the image forming stations Pa and P
b, Pc, and Pd are a black image, a cyan image, and
A magenta image and a yellow image are being formed.

On the other hand, each image forming station Pa, P
b, Pc, Pd, the photosensitive drum 1a,
An unsupported belt-shaped intermediate transfer belt 7 is arranged below 1b, 1c, and 1d, and moves in the direction of arrow A.

In such a structure, first, a latent image of a black component color of image information is formed on the photosensitive drum 1a by a known electrophotographic process means such as the charging means 2a of the first image forming station Pa and the exposing means 3. Thereafter, this latent image is visualized as a black toner image by a developing material having black toner by the developing means 4a, and the black toner image is transferred to the intermediate transfer belt 7 by the transfer means 5a.

On the other hand, while the black toner image is being transferred to the intermediate transfer belt 7, the second image forming station P
In b, a latent image of a cyan component color is formed, subsequently, a cyan toner image is obtained by the developing device 4b with cyan toner, and the cyan toner image is transferred to the intermediate transfer belt 7 after the transfer is completed at the first image station Pa. 2 image stations P
It is transferred by the transfer means 5b of b and is superimposed on the black toner image.

After that, image formation is performed on the magenta toner image and the yellow toner image in the same manner, and when the superimposing of the four color toner images on the intermediate transfer belt 7 is completed, the paper feed roller 8 is used to feed the paper. A toner image of four colors is collectively transferred and conveyed by a sheet material transfer roller 11 onto a sheet material 9 such as paper fed from 10, and is fixed by heating by a fixing means 12 to obtain a full color image on the sheet material 9.

The photosensitive drums 1a, 1b, 1c and 1d, which have completed the transfer, are cleaned by the cleaning means 6a,
The residual toner is removed by 6b, 6c, and 6d, and the toner is prepared for the subsequent image formation.

As described above, in the apparatus having a plurality of image forming stations Pa, Pb, Pc and Pd, the scanning lines 3K, 3C, 3M and 3Y of the laser beam emitted by the laser light source from the exposure means 3 are used for drawing. Image information is exposed on the photosensitive drums 1a, 1b, 1c, 1d that rotate in the direction of the middle arrow C, and the same intermediate transfer belt 7 is conveyed in the direction of the arrow A in the figure through a known image forming process. Images of different colors are sequentially transferred onto the surface and superposed, but if the transfer image position in each of the image forming stations Pa, Pb, Pc, Pd deviates from the ideal position, for example, in the case of a multicolor image, the image intervals of different colors are changed. It will be shifted or overlapped. Further, in the case of a color image, the difference in color tint appears, and when the degree becomes more severe, a color shift appears, which significantly deteriorates the image quality.

Therefore, in the embodiment of the present invention, in order to eliminate the four types of misregistration that cause the color misregistration described in the conventional example, first, as for the top margin and the left margin, the scanning lines 3K, The amount of deviation is corrected by electrically adjusting the scanning timings of 3C, 3M, and 3Y.

With respect to the magnification error shift, the video clock rates of the scanning lines 3K, 3C, 3M and 3Y are electrically modulated to correct the shift amount.

Finally, with respect to the tilt deviation in the oblique direction, the deviation amount is corrected by the method described below. The tilt deviation (skew) correction system according to the present invention will be described with reference to FIGS.

The photosensitive drum 1a of the first image station Pa is driven by the drive motor 13 as shown in FIG.
It is driven to rotate in the direction. On the surface of the photosensitive drum 1a having the same peripheral speed (transfer speed) as the transfer speed (transfer speed) of the intermediate transfer belt 7, the laser beam scanning line 3K causes the scanning end point E in the direction of arrow H from the scanning start point D. The latent image line e of the black component color of the image information having a preset inclination is formed.

Here, if the rotational speed of the drive motor 13 is increased and the peripheral speed of the photosensitive drum 1a is made faster than the conveying speed of the intermediate transfer belt 7 (reference speed of the photosensitive drum 1a),
The latent image line that has started writing from the scanning start point D moves to the position of the scanning end point F and forms a latent image line f having a smaller inclination angle than the latent image line e.

Next, the latent image line f is visualized by the developing means 4a and transferred to the intermediate transfer belt 7 by the transfer means 5a as shown in FIG. However, since the peripheral speed of the photoconductor drum 1a is faster than the conveying speed of the intermediate transfer belt 7, the visible line of the latent image line f is inclined to the inclination of the transfer line g on the intermediate transfer belt 7. The angle is decreasing (the line f ′ in FIG. 3 is a transfer line when the peripheral speed of the photosensitive drum 1a and the conveyance speed of the intermediate transfer belt 7 are the same). Further, if the peripheral speed of the photosensitive drum 1a is set lower than the conveying speed of the intermediate transfer belt 7, the inclinations of the latent image line and the transfer line will shift in the expanding direction.

By the way, in the embodiment of the present invention, the latent image line e is formed with an inclination with respect to the direction perpendicular to the rotation direction of the photosensitive drum 1a. Intermediate transfer belt 7 for changes in peripheral speed of 1a
This is to increase the variation rate of the inclination of the transfer line g above.

The reason why the variation rate of the inclination becomes large is that when the latent image line f is formed in a direction perpendicular to the rotation direction of the photosensitive drum 1a, the transfer is performed even if the peripheral speed of the photosensitive drum 1a changes. The line g remains in the direction perpendicular to the rotation direction of the photoconductor drum 1a, and the latent image line f is formed with an inclination with respect to the direction perpendicular to the rotation direction of the photoconductor drum 1a. Considering that the inclination of the transfer line g changes when the peripheral speed of the drum 1a changes, the latent image line f
It can be seen that the greater the inclination of the photosensitive drum 1a in the direction perpendicular to the rotation direction of the photosensitive drum 1a, the greater the inclination of the transfer line g on the intermediate transfer belt 7 with respect to the change in the peripheral speed of the photosensitive drum 1a. Therefore, the latent image line e is formed so as to be inclined with respect to the direction perpendicular to the rotation direction of the photosensitive drum 1a.

By forming with this inclination,
The variation rate of the inclination of the image on the intermediate transfer belt 7 with respect to the change in the peripheral speed of the photoconductor drum 1a is increased, and
The inclination shift in the oblique direction can be adjusted with a minimum change in the peripheral speed of a, the adjustment of the inclination shift can be simplified and the cost can be reduced, and the inclination shift can be easily adjusted. It is possible to obtain a high-quality image without image deterioration by eliminating the deviation of each pixel when the scanned images are superposed.

The latent image line e is sequentially formed on the surface of the photosensitive drum 1a by the exposing means 3 from the scanning start point D to the scanning end point E in the direction of arrow H as in the embodiment of the present invention. Assuming that the relative position between the exposure unit 3 and the photosensitive drum 1a is downstream of the scanning end point E with respect to the scanning start point D in the rotational direction of the photosensitive drum 1a, the photosensitive drum 1a with respect to the reference speed. When the peripheral speed of 1a is slower, the fluctuation rate of the inclination of the scanning line on the intermediate transfer belt 7 with respect to the change of the peripheral speed of the photosensitive drum 1a is larger than that when the peripheral speed of 1a is fast.

This is shown in FIG. 2 of the embodiment of the present invention.
As shown in, when the peripheral speed of the photoconductor drum 1a is faster than the reference speed of the photoconductor drum 1a, the inclination of the latent image line f moves in the direction perpendicular to the rotation direction of the photoconductor drum 1a. When the peripheral speed of the photosensitive drum 1a is slower than the reference speed of 1a, the inclination of the latent image line f moves in a direction away from the direction perpendicular to the rotating direction of the photosensitive drum 1a.

In this way, the exposure means 3 and the photosensitive drum 1
The relative position with respect to a is set so that the scanning end point E is located downstream of the scanning start point D with respect to the rotation direction of the photosensitive drum 1a, so that the peripheral speed of the photosensitive drum 1a is slower than that of the faster one. Since the fluctuation rate of the inclination of the image on the intermediate transfer belt 7 becomes large and the peripheral speed of the photosensitive drum 1a is changed in a region slower than the reference speed of the photosensitive drum 1a, the photosensitive drum 1a is transferred. The tilt deviation in the oblique direction can be adjusted in a region where the load torque of the drive source is small, and a high quality image can be obtained.

On the other hand, in contrast to the above-described embodiment of the present invention, the latent image line e is moved relative to the relative position between the exposure means 3 and the photosensitive drum 1a so that the scanning end point E is relative to the scanning start point D. If the upstream side of the rotation direction of the
The fluctuation rate of the inclination of the scanning line on the intermediate transfer belt 7 with respect to the change of the peripheral speed of the photoconductor drum 1a becomes larger when the peripheral speed of the photoconductor drum 1a is slower than the reference speed.

This is because when the peripheral speed of the photoconductor drum 1a is slower than the reference speed of the photoconductor drum 1a, the inclination of the latent image line f moves in the direction perpendicular to the rotation direction of the photoconductor drum 1a. The photosensitive drum 1 with respect to the reference speed of the drum 1a
When the peripheral speed of a is high, the inclination of the latent image line f is
This is because the rotation direction of a means to move away from the direction at right angles.

In this way, the exposure means 3 and the photosensitive drum 1 are
The relative position with respect to a is set so that the scanning end point E is upstream of the scanning start point D with respect to the rotation direction of the photosensitive drum 1a, so that the faster peripheral speed of the photosensitive drum 1a is compared to the slower peripheral speed. The variation rate of the inclination of the image on the intermediate transfer belt 7 becomes large, and the inclination deviation in the oblique direction can be adjusted in a region where the peripheral speed of the photosensitive drum 1a is faster than the conveying speed of the intermediate transfer belt 7 where the transfer efficiency is improved. At the same time, the peripheral speed of the photoconductor drum 1a is changed in a region higher than the conveying speed of the intermediate transfer belt 7, so that the inclination deviation in the oblique direction is always applied to the intermediate transfer belt 7 under tension. Can be adjusted and a high quality image can be obtained.

Hereinafter, the cyan image, the magenta image, and the yellow image are formed in the same manner while changing the inclination of the transfer line, and four color toner images are formed on the intermediate transfer belt 7.

As described above, by changing the inclination of the transfer line, the peripheral speeds of the photosensitive drums 1a, 1b, 1c and 1d are changed so that the inclinations of the transfer lines of the respective color images are the same,
Correct tilt deviation. For example, the peripheral speeds of the other photoconductor drums 1b, 1c, 1d are independently changed to match the tilt angle of the transfer line g of the photoconductor drum 1a, and the misalignment amount is corrected by adjusting the tilt angles to match. Then, the superposition of the four color toner images having no color shift on the intermediate transfer belt 7 is completed.

However, in the above configuration, as shown in FIG. 4, the black transfer line 14a and the cyan transfer line 14 are
b, magenta transfer line 14c, yellow transfer line 1
The inclination angles of 4d are corrected for each other,
Since the latent image line f is inclined, the output image is not a rectangle but a parallelogram whose interior angles are not right angles, which causes image deterioration.

An embodiment for correcting an output image of a parallelogram whose interior angles are not right angles will be described with reference to FIGS. 5, 6 and 7. FIG. 5 is a state diagram of correction of a parallelogram shape on a writing area on an image carrier using the multiplex image forming apparatus according to one embodiment of the present invention, and FIG. 6 shows the multiplex image forming apparatus according to one embodiment of the present invention. FIG. 7 is a parallelogram correction output state diagram of the transfer area, and FIG. 7 is a parallelogram correction output state diagram using the multiplex image forming apparatus according to one embodiment of the present invention.

The first transfer vertical line 7a is a vertical line with respect to the transfer belt conveyance direction, and a scanning start point D is provided at an intersection with the scanning start side rotational direction line 1m of the photosensitive drum 1a, and the photosensitive drum at this position. The first rotation center is O. In addition, the scanning end point F of the scanning line f and the photosensitive drum 1
The rotation axis line 1n of the scanning end point side is provided by inclining the rotation axis 1p of the photosensitive drum 1a between the intersection F of the scanning end point side a of the scanning end point and the line 1n of the scanning end point side. The second rotation center of the photosensitive drum of the second vertical line 7b with respect to the transfer belt conveyance direction passing through the intersection of

The scanning start point D, which is a latent image formed in the writing area, rotates around the photosensitive drum center O, passes through the developing means 4a, is developed, and is in the transfer area in contact with the intermediate transfer belt 7, the first A transfer image is obtained on the transfer vertical line 7a. Further, since the scanning end point F rotates about the second rotation center of the photoconductor drum about O ′, it passes through the developing means 4a and is developed, and in the transfer area in contact with the intermediate transfer belt 7, on the first transfer vertical line 7a. Then, a transfer image is obtained, a transfer line g which coincides with the first transfer vertical line 7a is obtained, and the inclination correction is completed. Hereinafter, the cyan image, the magenta image, and the yellow image are also formed by the same method, and the black transfer line 15 is formed on the intermediate transfer belt 7 as shown in FIG.
a, cyan transfer line 15b, magenta transfer line 15
c, the yellow transfer line 15d is corrected for the respective inclination angles of the four colors, and at the same time, the correction for converting the parallelogram-shaped image whose interior angle is not a right angle into a rectangular image in which the interior angle is substantially right is also completed. An image is obtained.

If the rotary shaft 1p of the photoconductor drum 1a is arranged so as to be inclined at about 1/2 of the inclination angle formed by the scanning line f and the first transfer vertical line 7a, the scanning line f coincides with the transfer line g. The output image can be rectangular.

Further, as shown in FIG. 8, for example, the print center 16 is at the center (centers of the respective photosensitive drums 1a to 1d).
If the photoconductor drums 1a to 1d are rotated and the rotation shafts 1p to 1s are tilted, the image forming stations Pa to Pd are moved to tilt the photoconductor drums 1a to 1d. The area can be minimized and, as a result, the machine size does not increase.

Further, as shown in FIG. 9, when the photosensitive drums 1a to 1d are rotated together around a predetermined point and the rotary shafts 1p to 1s are tilted, the drive motor 13 is constituted.
Since the shape of the drive motor mounting metal plate 17 for mounting the a to 13d can be made flat, it is possible to improve the accuracy of the mounting reference positions of the image forming stations Pa to Pd even when the drive motor mounting metal plate is not flat.

[0057]

As described above, according to the present invention, a plurality of photoconductors, exposure means for irradiating each of the photoconductors with light to form a latent image, and latent images formed on the photoconductors. And a transfer means for transferring the image visualized by the developing means onto the transfer material, and the visualized images on the respective photoconductors are sequentially superposed on the transfer material. In a multiple image forming apparatus that forms a combined image at the same time, the exposure means is arranged so that the exposure means scans the photoconductor at a predetermined inclination with respect to the direction perpendicular to the transfer direction of the photoconductor. The photoconductors are arranged such that the direction perpendicular to the transfer direction of the body is located between the inclination of the scanning line by the exposure means and the direction substantially perpendicular to the transfer direction of the transfer material. This is equipped with a speed adjustment unit that changes the output. Corrects image distortion, which is not a rectangle but a parallelogram whose inside angles are not right angles, during transfer to the transfer material during transfer, and keeps the output image as a rectangular image with an inside angle of about 90 degrees The misregistration can be adjusted by changing the transfer speed of the photoconductor, which simplifies the structure of the color misregistration correction unit and reduces the cost, and facilitates the color misregistration adjustment. It is possible to obtain an advantageous effect that it is possible to obtain a high-quality image without image deterioration by eliminating the displacement of each pixel when the optical scanning images of the photoconductors are superposed.

Further, the inclination angle of the direction perpendicular to the transfer direction of the transfer material to the direction perpendicular to the transfer direction of the photoconductor is the inclination angle of the scanning line of the exposure means with respect to the direction perpendicular to the transfer direction of the transfer material. Since the output image is not a rectangle but a parallelogram whose interior angles are not right angles due to the inclination of the scanning line, the distortion of the image is accurately corrected when the image is transferred to the transfer material in the transfer area. , While keeping the output image as a rectangular image having a right angle inside angle, it is possible to adjust the tilt deviation by changing the transfer speed of the photoconductor, simplifying the structure of the color misregistration correction unit and reducing the cost, Further, it is possible to easily perform color misregistration adjustment, eliminate misalignment of each pixel when superimposing optical scanning images by a plurality of light beams and a plurality of photoconductors, and obtain a high-quality image without image deterioration. Advantage Effect can be obtained.

Further, each photoconductor is rotated about a predetermined location in each photoconductor that is determined in advance, and the photoconductor is given an inclination angle, so that the photoconductor is inclined in an oblique direction without increasing the machine size. Adjustment of the inclination deviation of the color misregistration can be performed, the structure of the color misregistration correction unit can be simplified and the cost can be reduced, and the color misregistration can be easily adjusted. In this case, there is an advantageous effect that it is possible to obtain a high-quality image with no image deterioration without misalignment of each pixel.

Further, since all the photoconductors are rotated about a predetermined point as an axis and the photoconductors are inclined, the end portions in the direction perpendicular to the transfer direction of the plurality of photoconductors are formed. It can be arranged on a straight line, and tilt deviation can be adjusted while maintaining high accuracy when arranging a plurality of photoconductors, which simplifies and reduces the cost of the color misregistration correction unit, and further the color misregistration. It is advantageous in that it is possible to easily perform the adjustment, eliminate the deviation of each pixel when a plurality of light beams and the light scanning images of a plurality of photoconductors are superposed, and obtain a high-quality image without image deterioration. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a multiplex image forming apparatus using a multiplex image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a color misregistration correction state diagram on an image bearing member using a multiplex image forming apparatus according to an embodiment of the present invention.

FIG. 3 is a transfer region color misregistration correction state diagram using a multiplex image forming apparatus according to an embodiment of the present invention.

FIG. 4 is a tilt angle correction output state diagram using a multiplex image forming apparatus according to an embodiment of the present invention.

FIG. 5 is a parallelogram shape correction state diagram of a writing area on an image carrier using a multiplex image forming apparatus according to an embodiment of the present invention.

FIG. 6 is a transfer region parallelogram shape correction state diagram using a multiplex image forming apparatus according to an embodiment of the present invention.

FIG. 7 is a parallelogram correction output state diagram using a multiplex image forming apparatus according to an embodiment of the present invention.

FIG. 8 is a top view of a multiple image forming apparatus according to another embodiment of the present invention.

FIG. 9 is a top view of a fourth image forming apparatus according to another embodiment of the present invention.

FIG. 10 is a diagram showing various kinds of errors in scanning lines using a conventional multiplex image forming apparatus.

FIG. 11 is a perspective view showing a schematic configuration of a correction apparatus using a conventional multiple image forming apparatus.

[Explanation of symbols]

1a photoconductor drum 1p rotation axis 2a charging means 3 exposure means 3K laser beam scanning line 4a developing means 5a transfer means 6a Cleaning means 7 Intermediate transfer belt 8 paper feed rollers 9 sheet materials 11 Sheet material transfer roller 12 Fixing means 13 Drive motor f scan line

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/01-15/01 117 B41J 2/44

Claims (4)

(57) [Claims] 1. A plurality of photoconductors, an exposure unit that irradiates each of the photoconductors with light to form a latent image, and a plurality of developing units that visualize the latent images formed on each of the photoconductors. And a transfer unit that transfers the image visualized by the developing unit to a transfer material, and sequentially superimposes the image visualized on each of the photoconductors on the transfer material to form a composite image. In the multiplex image forming apparatus, the exposing means is arranged so that the exposing means scans the photoreceptor with a predetermined inclination with respect to a direction perpendicular to the transfer direction of the photoreceptor, and The photoconductor is arranged such that the direction perpendicular to the transfer direction of the transfer medium is located between the inclination of the scanning line by the exposure means and the direction substantially perpendicular to the transfer direction of the transfer material. Multiple image forming apparatus characterized by including speed adjusting means for changing the transfer speed . 2. An inclination angle of a direction perpendicular to the transfer direction of the photoconductor with respect to a direction perpendicular to the transfer direction of the transfer material,
2. The multiple image forming apparatus according to claim 1, wherein an inclination angle of the scanning line by the exposing unit with respect to a direction perpendicular to the transfer material transport direction is approximately 1/2. 3. The multiple image formation according to claim 1, wherein each of the photoconductors is rotated about a predetermined position in each of the photoconductors as a shaft to give an inclination angle to the photoconductor. apparatus. 4. A multiple image forming apparatus according to claim 1, wherein all the photoconductors are rotated about a predetermined point as an axis to give an inclination angle to the photoconductors.