JPH056071A - Color image forming device - Google Patents

Abstract

PURPOSE:To easily excute adjustment working in a short time with low cost and simple constitution. CONSTITUTION:The fitting part 33 of a write optical device is pressurized to an adjusting block 58 by an axis 52 which is fixed to the block 58, a spring 53, a washer 55 and a stop ring 54 and an adjusting screw 56 is capable of adjusting the position of the attaching part 33. The adjusting block 58 is supported to a stay 37 rotatably centering around an axis 61 and pressed upper direction by a spring 63, then positioned by an adjusting screw 62. By adjusting the screw 56 C and D directions and the screw 62 to A and B direction, a fitting position is corrected and color slurring is easily adjusted at both sides images.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention emits scanning light of each color by a writing optical device to write an image of each color on each image carrier to form a latent image, which is developed with toner. The present invention relates to a color image forming apparatus that superimposes and transfers a toner image of each color onto a conveyed transfer paper by aligning the image position of each color.

[0002]

2. Description of the Related Art In a color image forming apparatus of a superposition transfer system using a plurality of image bearing members, toner images of four colors or three colors are superposed on each other to reproduce the original color and image. If the image positions do not match, color misregistration occurs and the image quality deteriorates. The causes of this color misregistration are roughly classified into those caused by rotation accuracy such as rotation unevenness and relative speed difference, and those caused by mounting position error of the writing optical device, the image carrier, or the transport device. .

As a method of preventing or adjusting the mounting position error, the present inventor has already proposed a method of adjusting the inclination of the scanning line on the image by adjusting the inclination of the axis of the image carrier (for example, Japanese Utility Model Laid-Open No. 63-185151). JP-A-62-22922
No. 64), a method of preventing a repetitive error of the main body mounting position of the writing optical device by taper fitting the writing optical device (see Japanese Patent Laid-Open No. 2-220072), on the transfer belt. Of adjusting the position in the paper transport direction by detecting the image of the image and controlling the writing start timing (for example, see Japanese Patent Laid-Open No. 63-43172).
And so on.

As an automatic adjustment device for color misregistration, a large number of devices have been proposed which detect a color misregistration amount on an image and adjust a tilt of an image carrier axis provided for each color. (See, for example, Japanese Patent Laid-Open No. 64-6981).

[0005]

As the form of color misregistration, in addition to the above, the difference in relative magnification (writing width) of each color and the relative color of each color in the direction perpendicular to the paper conveyance direction (horizontal registration). There is a positional shift. Regarding this magnification and lateral resist, it is common to adjust the exposure scanning range of the image light of four colors (or three colors) using a jig etc. before attaching the writing optical device to the main body. Is.

However, even if adjustment is made with a jig or the like, if an error occurs in the attachment position of the writing optical device to the apparatus main body, color misregistration occurs, and it is necessary to adjust both the magnification and the lateral resist again after attachment. That is, as shown in FIG. 7, when the heights of the left and right stays 37 of the writing optical device provided in the main body are deviated, the writing optical device is tilted and placed, which causes a difference in optical path length.

As a result, the actual shift amount e between the illustrated BK image and Y image is Δltan θ with respect to the optical path length difference Δl. Since the irradiation angle θ is usually about 20 °, Δl
tan θ≈1 / 3Δl. Therefore, for example, if the difference in mounting height is 0.2 mm, the deviation amount e is about 67
μm, and a shift corresponding to one dot in the case of an image of 400 dpi occurs.

On the other hand, as shown in FIG. 8, when the writing optical device is installed so as to be inclined with respect to the paper transport direction of the transport device, the transfer paper is transferred even if the exposure position is adjusted on the jig. The image on P is displaced in the direction perpendicular to the carrying direction (main scanning direction).

In order to prevent color shift due to these two causes, after the writing optical device is attached to the main body, the mirror attachment position in the writing optical device is adjusted again, or electrically, the reference clock frequency is set. It is necessary to adjust other colors so as to match the reference color (for example, BK) by adjusting the magnification by the fine adjustment of and the writing start timing after the synchronization detection. The same adjustment is performed on the jig and after the main body is attached. Since it has to be performed once, the adjustment time increases, which causes a cost increase.

Further, since a fine adjustment circuit for the reference clock frequency is required to electrically adjust the magnification, the cost is increased and the reference clock frequency becomes unstable.

In this case, the above-mentioned publication (Japanese Patent Laid-Open No. 64-698).
If an automatic adjustment device represented by the technology of No. 1) is adopted, all the adjustment work related to the image forming position becomes unnecessary. For that purpose, a deviation amount detection device, a unit position correction device, Furthermore, a control circuit is required, which increases the cost and the size of the entire device. Since each adjustment unit needs to be movably held, image deterioration is likely to occur due to vibration or the like during operation of the image forming apparatus.

Therefore, an object of the present invention is to provide a color image forming apparatus which solves the above-mentioned problems and has a simple structure which does not require cost and which can easily perform an adjusting operation in a short time.

[0013]

In order to solve the above-mentioned problems, the present invention provides an image carrier for each color arranged in parallel in the carrying direction which is a direction perpendicular to the scanning direction, in the upstream of the carrying direction. Side and downstream side, the writing optical device supported by the main body emits scanning light of each color from a position facing each of the image carriers to write a color image on each image carrier to form a latent image. To develop the latent image with toner,
A color image forming apparatus for superposing and transferring the toner images of the respective colors on the conveyed transfer paper by aligning the image positions of the respective colors, the invention according to claim 1 is characterized in that the writing optical device is supported by the main body. The invention according to claim 3 is characterized in that a distance adjusting means for adjusting a distance between the writing optical device and the image carrier is provided on at least one side of an upstream side or a downstream side of the supporting portion. One of a plurality of supporting portions of the writing optical device for supporting the main body of the image forming apparatus is rotatably provided in the writing optical device in a plane parallel to the axial surface of the image carrier. At least another one of the other supporting portions supporting the device and excluding one of the supporting portions has a rotating means for rotating the writing optical device. According to a fourth aspect of the present invention, the image forming device of the writing optical device is provided. Of the plurality of supporting portions for the main body, one supporting portion rotatably supports the writing optical device in a plane parallel to the axial surface of the image carrier arranged side by side, The supporting portion on the opposite side of the supporting portion has a rotating means for rotating the writing optical device and a distance adjusting means for adjusting the distance between the writing optical device and the image carrier. To do. The invention of claim 2 is the same as claim 1
In addition to the features of the invention described above, the support portion provided with the distance adjusting means applies pressure from the direction of adjusting the distance so that the writing optical device can be displaced in a direction perpendicular to the direction of adjusting the distance. It is characterized by being supported by.

[0014]

According to the present invention, the distance adjusting means for adjusting the distance between the writing optical device and the image carrier is provided on at least one side of the upstream or downstream side supporting portion of the writing optical device. Since the height of the writing optical device in the transport direction is adjusted by the distance adjusting means even if color misregistration occurs in the main scanning direction due to a magnification error based on the mounting height error, the distance between the upstream side and the downstream side is adjusted. By comparing the images on the image carrier, the adjustment can be easily and quickly performed.

According to the invention of claim 2, in addition to the above,
Since the writing optical device is supported by being pressed from the direction in which the distance is adjusted so as to be displaceable, thermal stress does not occur even when the writing optical device thermally expands.

According to the third aspect of the present invention, one support portion rotatably supports the writing optical device in a plane parallel to the axial surface of the image carrier, and at least another one support portion performs writing. Since the rotating means for rotating the optical device is provided, even if a color shift due to lateral registration shift occurs due to a relative mounting error between the writing optical device and the conveying device on the axial surface of the image carrier, the rotating means can rotate. By adjusting the lateral resist and comparing the images on the image carrier at both ends of the upstream side and the downstream side, the adjustment can be easily performed in a single time.

According to the fourth aspect of the invention, since the distance adjusting means and the rotating means are provided, the color shift in the main scanning direction and the color shift due to the lateral registration shift can be easily adjusted in a single time.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a schematic structure of an example of a color image forming apparatus to which the present invention can be applied. This apparatus comprises a document reading section 1, an image processing section 2 and a printer section 3.

The color original placed on the original placing table 4 of the original reading section 1 is optically scanned by the white lamp 5, and the reflected light is reflected by the first, second and third mirrors 6, 7, 8. CCDs 11B and 11 are provided for each color light separated into three color lights of blue, green and red by a dichroic prism 10 via a lens 9.
An image is formed on G and 11R, read, and output as a digital signal.

An image information signal to be developed in each color of yellow, magenta, cyan, and black (hereinafter abbreviated as Y, M, C, and BK) is subjected to necessary processing in the image processing unit 2 for each color digital signal. Laser beam 24Y, 24M, 24C, 24 which is converted into a laser beam by a semiconductor laser and is input to a laser driving unit of a laser writing optical device 12 as a writing optical device of the printer unit 3 and modulated by a semiconductor laser.
BK is emitted.

Each laser beam is incident on one of the two rotary polygon mirrors, and Fθ lenses 26Y, 26M, 26
Photoconductors 14Y, 14M, 14C, 14BK as image carriers for each color, which are arranged in parallel in the transport direction, which is a direction perpendicular to the main scanning direction, via C, 26BK and the mirror 27.
Is emitted from each of the emission ports extending in the main scanning direction of the laser writing optical device at a position opposite to the writing position, and each photoconductor drum is main-scanned in the length direction. A charging charger is provided around each photoconductor drum 14 (subscripts Y, M, C, and BK in the drawing indicate devices attached to the photoconductors to be developed in yellow, magenta, cyan, and black, respectively). 15, the writing position, the developing device 16, the transfer charger 17
Are provided to configure a four-color recording device 13.

The transfer paper sent from the paper supply unit 19 by the paper supply roller 18 passes through the registration roller 20 and the transfer belt 2.
1 is sequentially conveyed via the transfer section between each transfer charger 17 and the photoconductor 14, and BK, C,
After the respective color toner images of M and Y are transferred in alignment with each other, they are fixed by the fixing device 22 and ejected outside the device by the ejection roller 23 to complete the recording.

In such a superposition transfer type color image forming apparatus, since the toner images of four colors are superposed and the color and the image of the original are reproduced, the laser writing optical device 12 emits the light from each emission port. If the main scanning range of the generated laser light does not match in the width direction of each photoconductor drum, color misregistration occurs and image quality deteriorates. Therefore, the laser writing optical device adjusts the exposure scanning range of the image light of four colors by using a jig or the like before attaching the laser writing optical device to the reference pin and the reference hole. Is used to accurately position and attach to the image forming apparatus.
However, it is not easy to accurately position the lateral resist with respect to the height between the upstream side and the downstream side in the transport direction of the laser writing optical apparatus and the transport direction. Therefore, according to the present invention, the support portion is not provided in the present embodiment. Is provided with the following distance adjusting means and rotating means. 2A and 2B show an example of the distance adjusting means of the present invention provided in a supporting portion, FIG. 2A is a front view, and FIG. 2B is a view showing a mounting hole shape of a writing optical device casing. In this embodiment, a height adjusting device 41 is provided as a distance adjusting means on the left side mounting portion 33 as a supporting portion of the writing optical device 12.

The height of the left stay of the main body is set to H lower than that of the right stay. With respect to the stay 37, the height adjusting shaft 42 uses a jig, a spacer 45 having a height h, and the like so that the seat surface 42b is higher than the stay surface by H, and the thread portion 37a of the stay. Are joined by and. Then, the mounting portion 33 hole of the writing optical device 12 is penetrated through the reference portion 42c of the height adjusting shaft, and is received by the seat surface 42b. Further, the mounting portion 33 is pressed against the seat surface 42b by the spring 43 and the retaining ring 44.

With the above construction, when the shaft 42 is rotated, the mounting height can be adjusted in the direction of arrow A in the figure,
It is possible to adjust the distance in the height direction shown in FIG. The adjustment work can be simplified because the adjustment can be made by looking at the difference in magnification between the colors (BK and Y in the example) of the image carriers at both ends.

In this embodiment, the mounting portion 33 of the writing optical device is pressed against the seat surface 42b of the shaft by the spring 43. This is done when the casing of the writing optical device is thermally expanded due to temperature change. This is because it can move freely in the direction of arrow B in FIG. For this reason, the hole of the mounting portion 33 has an elongated hole shape. However, if this is not necessary, as shown in FIG.
The mounting portion 33 may be fixed to the shaft by 6.

4 and 5 show an embodiment in which a rotating means is provided in the supporting portion. In FIG. 4 showing the attachment of the writing optical device to the main body, the device is supported at three points, that is, two mounting portions 32a and 32b with respect to the right stay 37 and one mounting portion 33 with respect to the left stay 37. Has been done. Of these, one portion 32a of the right stay is a reference hole portion, and the other two portions have a hole diameter with a gap with respect to the pin diameter.
The left stay is provided with an adjusting device 51 as a rotating means.

FIG. 5 is a detailed view of the adjusting device 51. The writing optical device mounting portion 33 includes a shaft 52 fixed to the stay 37, a spring 53, a washer 55, and a retaining ring 54.
It is pressed against the stay 37 by. Also, stay 3
7 includes an adjusting screw holder 37a and a spring holder 37b.
The mounting portion 33 is pressed by the adjusting screw 56 by the action of the spring 57. With the above configuration, the writing optical device 12 can freely rotate in the C or D direction with the reference portion 32a as the center of rotation by turning the adjustment screw, and due to the inclination of the transport portion and each color as shown in FIG. It is possible to correct the color shift of the lateral resist. As the adjustment work, it suffices to correct the color difference (BK and Y in the example) of the image bearing members at both ends by the deviation of the lateral resists, and the adjustment work is simplified.

FIG. 6 shows a height and lateral registration adjusting device 60 of an embodiment in which a distance adjusting means and a rotating means are provided at the same time on one supporting portion. Writing optical device mounting portion 33
Is pressed against the block 58 by a shaft 52, a spring 53, a washer 55, and a retaining ring 54 that are fixed to the adjustment block 58, and the position can be adjusted in the directions C and D in the figure by an adjustment screw 56. Further, the adjustment block 58 is supported rotatably around the shaft 61 with respect to the stay 37, and is upward by a spring 63 (A in the figure).
Direction), and the position is determined by the adjusting screw 62. With the above configuration, the screws 56,
By adjusting the screw 62 in the A and B directions, the mounting position can be corrected. Also, according to the embodiment of FIG.
The adjustment in the AB direction can be made more finely than the embodiment shown in FIG. 2 by the lever ratio.

The present invention has been described above with reference to the embodiments.
The device configuration, such as the position where the adjusting device is provided and the configuration of the adjusting device itself, is not limited to the above as long as the same effect can be obtained.

[0031]

As described above, according to the present invention, in the first aspect of the present invention, by providing the distance adjusting means, even if the color shift occurs in the main scanning direction due to the magnification error based on the mounting height error, By adjusting the height of the writing optical device in the transport direction and comparing the images on the image carriers at both ends of the upstream side and the downstream side, the adjustment can be simplified and the time can be shortened.

According to the invention of claim 2, in addition to the above, since the writing optical device is supported by being pressed from the direction of adjusting the distance so that it can be displaced, when the writing optical device thermally expands. Also, the generation of thermal stress can be avoided.

According to the third aspect of the present invention, since the rotating means for rotating the writing optical device is provided, the lateral registration shift due to a relative mounting error between the writing optical device and the conveying device on the axial surface of the image carrier. Even if color misregistration occurs due to, the lateral registration is adjusted by the rotating means, and the image misregistration is easily adjusted in a short time by comparing the images on the image carriers at both ends of the upstream side and the downstream side. be able to.

According to the invention of claim 4, since the distance adjusting means and the rotating means are provided, the color shift in the main scanning direction and the color shift due to the lateral registration shift can be adjusted at one place.
Workability and serviceability can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an image forming apparatus according to an embodiment.

2A is a sectional view of a height adjusting device of a writing optical device of the image forming apparatus, and FIG. 2B is a plan view of a mounting hole thereof.

FIG. 3 is a sectional view of a height adjusting device according to another embodiment.

FIG. 4 is a plan view of a supporting portion of the writing optical device of the image forming apparatus according to the embodiment.

FIG. 5 is a sectional view of the lateral resist adjustment described above.

FIG. 6 is a cross-sectional view of a height and lateral resist adjusting device.

FIG. 7 is an explanatory diagram of color shift when the height of a supporting portion of the writing optical device is changed.

FIG. 8 is an explanatory diagram of color shift when the lateral resist of the supporting portion of the writing optical device is misaligned.

[Explanation of symbols]

12 laser writing optical device (writing optical device) 14 photoconductor (image carrier) 41 height adjusting device (distance adjusting means) 51 lateral registration adjusting device (rotating means) 60 height and lateral registration adjusting device (distance) Adjusting means and rotating means)

Claims (4)

[Claims] 1. A writing optics supported by a main body on the upstream side and the downstream side in the carrying direction on image carrying bodies of respective colors arranged in parallel in the carrying direction which is a direction perpendicular to the main scanning direction. The apparatus emits scanning light of each color from a position facing each of the image carriers to write an image of each color on each image carrier to form a latent image, and the latent image is developed with toner, and each color is developed. A color image forming apparatus for superimposing and transferring the toner images of the respective colors onto the conveyed transfer paper by aligning the image positions of the respective colors, the writing optical device is supported on the upstream side or the downstream side of the supporting portion supported by the main body. A color image forming apparatus, characterized in that distance adjusting means for adjusting a distance between the writing optical device and the image carrier is provided on at least one side of the portion. 2. The support portion provided with the distance adjusting means is supported by applying pressure from a distance adjusting direction so that the writing optical device can be displaced in a direction perpendicular to the distance adjusting direction. The color image forming apparatus according to claim 1, wherein the color image forming apparatus is a color image forming apparatus. 3. A writing optics supported by an image carrier for each color arranged in parallel in a transport direction, which is a direction perpendicular to the main scanning direction, from the main body on the upstream side and the downstream side in the transport direction. The apparatus emits scanning light of each color from a position facing each of the image carriers to write an image of each color on each image carrier to form a latent image, and the latent image is developed with toner, and each color is developed. In a color image forming apparatus that superimposes and transfers the toner images of the respective colors onto the conveyed transfer paper by aligning the image positions of the respective colors, one of a plurality of supporting portions of the writing optical device for the image forming apparatus main body is , The writing optical device is rotatably supported in a plane parallel to the axial surface of the image carrier arranged side by side, and one of the supporting portions is removed from the other supporting portion. At least one other supporting portion is a rotation for rotating the writing optical device. A color image forming apparatus comprising means. 4. A writing optics supported by an image carrier for each color arranged in parallel in a transport direction, which is a direction perpendicular to the main scanning direction, from the main body on the upstream side and the downstream side in the transport direction. The apparatus emits scanning light of each color from a position facing each of the image carriers to write an image of each color on each image carrier to form a latent image, and the latent image is developed with toner, and each color is developed. In a color image forming apparatus that superimposes and transfers the toner images of the respective colors onto the conveyed transfer paper by aligning the image positions of the respective colors, one of a plurality of supporting portions of the writing optical device to the image forming apparatus main body is one supporting portion. , The writing optical device is rotatably supported in a plane parallel to the axial surface of the image carriers arranged in parallel, and the supporting portion on the opposite side of the one supporting portion in the transport direction is the writing optical device. Rotating means for rotating the device and the writing optical device and front A color image forming apparatus comprising a distance adjusting means for adjusting a distance to an image bearing member.