JP3725407B2 - Color image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic color image forming apparatus, and more particularly to a tandem type color image forming apparatus having a plurality of image forming stations.
[0002]
[Prior art]
Conventionally, in a tandem type color image forming apparatus formed by connecting a plurality of image forming stations for forming each color component image, the color component images formed at the respective image forming stations are superimposed on a transfer medium. A color image is formed.
[0003]
In such a method, an image is formed by different image forming means for each color component. For this reason, the positions and image formation timings of other image forming stations are adjusted in accordance with the position and size of the image formed at the reference image forming station so that the color component images are not shifted and color misregistration does not occur. To adjust. As a result, images formed at other image forming stations overlap on the transfer medium without shifting, and a good color image without color shift is formed.
[0004]
[Problems to be solved by the invention]
In such a tandem type image forming apparatus, the positional relationship between other image forming stations is adjusted with high accuracy on the basis of one image forming station. This adjustment is performed at the time of product assembly at the manufacturing factory, and the image forming apparatus as a product is shipped in an optimal adjustment state.
[0005]
However, as shown in FIG. 6, since the state of the place where the image forming apparatus Q is actually used (place where it is installed) is different from the manufacturing factory, distortion occurs in the frame of the image forming apparatus main body. As shown in FIG. 7, color misregistration may occur in the image on the recording paper P after passing through the transfer conveyance belt mechanism 513 including the driving roller 514, the driven roller 515, the transfer conveyance belt 516, and the like.
[0006]
This color shift is caused by the surface state of the floor F on which the image forming apparatus Q is installed. That is, since there is no place where the surface state of the floor F is completely horizontal, the image forming apparatus Q that is generally supported by the four support portions is fine unless the floor F has a very strong configuration. The color shift of the image occurs due to the influence of the surface condition such as unevenness.
[0007]
Therefore, by adjusting the height of the unevenness of the floor F by providing a height adjustment adjuster in the support portion or by inserting a thick sheet block between the image forming apparatus Q and the floor F. The image forming apparatus F is adjusted so as to be substantially horizontal, but these are considerably hard work because the image forming apparatus F is heavy.
[0008]
Further, it is extremely difficult to perform complete horizontal adjustment, and in particular, from each image forming station (photosensitive drums 522a, 522b, 522c, 5222d and laser beam scanner units 527a, 527b, 527c, 527d in FIG. 7). In the case of the tandem method that requires high accuracy in the positional relationship between each other, there is a high risk of color misregistration in the image. That is, due to distortion of the frame of the apparatus main body, the arrangement positions of the four image forming stations are long in the main scanning direction (a direction orthogonal to the sub-scanning direction of the image forming station indicated by a long arrow in FIG. 8). It may be distorted by the length L. This distortion appears as a color misregistration having a length L in the main scanning direction on the recording paper P conveyed in parallel in the sub-scanning direction.
[0009]
The present invention has been made in view of such circumstances, and color image formation that can easily adjust color misregistration caused by distortion of the image forming apparatus without adjusting the position of each image forming station. An object is to provide an apparatus.
[0010]
[Means for Solving the Problems]
According to the present invention, in a tandem type color image forming apparatus in which a plurality of image forming stations are arranged so as to face a transfer path of a transfer medium, a transfer transfer carrier unit or an intermediate transfer carrier unit; Either one A fulcrum part provided in the unit; Provided in one of the units, And an action point portion that performs adjustment for changing the conveyance direction, Said Transfer carrier unit or Said The intermediate transfer carrier unit is displaced parallel to the main scanning direction so as to change the transfer conveyance carrier or the transfer direction of the intermediate transfer carrier. Said Depending on the point of action The transfer conveyance carrier unit or the intermediate transfer carrier unit is pressed parallel to the main scanning direction. The color image forming apparatus is provided so as to be rotatable about the fulcrum portion.
[0011]
Here, examples of the transfer medium include a recording sheet and an intermediate transfer carrier. The transfer conveyance carrier unit includes a transfer conveyance carrier for transferring and conveying a transfer medium, and the intermediate transfer carrier unit includes an intermediate transfer carrier for intermediate transfer of the transfer medium. The fulcrum portion serves as a rotation center (pivot) when the units are rotated (pivoted) in order to change the transport direction of these units. The action point portion is a place where adjustment for rotating these units is performed. Also, Changing the transfer direction means changing the azimuth (transport inclination) of the transfer medium in the transport plane in a direction in which the color shift decreases while checking the color shift in the main scanning direction.
[0012]
In the color image forming apparatus configured as described above, the position of each image forming station and the image forming timing are adjusted for a long time as in the past by aligning the transfer medium conveyance direction with the image in which color misregistration has occurred. Therefore, it is possible to easily eliminate the color misregistration without making any adjustments, and it is possible to form a good image without color misregistration. Further, it is not necessary to make the structure of the color image forming apparatus stronger than necessary, and a tandem type image forming apparatus can be realized at low cost and low weight.
[0013]
A color image forming apparatus according to the present invention includes: A recording sheet as a transfer medium is transferred and conveyed by the transfer conveyance carrier, and color shift adjustment in the main scanning direction is performed by changing the conveyance direction of the transfer conveyance carrier. It is preferably configured to be performed. In the color image forming apparatus configured as described above, the conveyance direction of the recording paper can be easily changed by changing the conveyance direction of the transfer conveyance carrier, and the position and image formation timing of each image formation station. Therefore, it is possible to easily eliminate the color misregistration without adjusting the image taking a long time as in the prior art, and it is possible to form a good image without color misregistration.
[0014]
A color image forming apparatus according to the present invention includes: Color shift adjustment in the main scanning direction is possible by changing the transport direction of the intermediate transfer carrier that is the transfer medium. It is preferably configured to be performed. In the color image forming apparatus configured as described above, by changing the transport direction of the intermediate transfer carrier, the image can be superimposed on the intermediate transfer carrier so that there is no color misregistration. The color misregistration can be easily eliminated without adjusting the position and image formation timing over a long period of time as in the prior art, and it is possible to perform good image formation without color misregistration.
[0015]
A color image forming apparatus according to the present invention includes: The transfer conveyance carrier unit includes a transfer conveyance carrier, a drive roller, and a driven roller, and the intermediate transfer carrier unit includes an intermediate transfer carrier, a drive roller, and a driven roller. Is preferred.
[0016]
In the color image forming apparatus configured as described above, by adjusting the transport direction of the transfer transport carrier unit or the intermediate transfer support unit, a good transport state of the transfer transport support body or the intermediate transfer support body can be obtained. Since the conveyance direction can be adjusted while being maintained, simple color misregistration adjustment can be accurately and easily performed.
[0017]
A color image forming apparatus according to the present invention includes: The fulcrum part and the action point part Is preferably the same as the distance between the image forming stations at both ends of the plurality of image forming stations.
[0018]
Fulcrum As an example, the center of rotation (pivot) when rotating (pivoting) the unit is provided outside the frame of the transfer carrying carrier unit or intermediate transfer carrier unit, and the unit is rotated in order to change the carrying direction of these units. There is a place to become. Examples of the action point portion include an adjustment screw and an eccentric cam attached to the frames of these units.
[0019]
In the color image forming apparatus configured as described above, the adjustment amount of the transfer conveyance carrier unit or the intermediate transfer carrier unit in the conveyance direction matches the color misregistration amount of the image formed by the image forming stations at both ends. Adjustment can be made easily.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, two embodiments according to the present invention will be described with reference to the drawings. The present invention is not limited to these.
[0021]
Embodiment 1
As shown in FIG. 1, a digital color copying machine D which is an image forming apparatus according to Embodiment 1 of the present invention. ₁ In this configuration, an original table 111 and an operation panel (not shown) are provided on the upper surface of the copying machine main body 1, and an image reading unit 110 and an image forming station 210 are provided inside the copying machine main body 1. The document table 111 is supported on the upper surface of the document table 111 so as to be openable and closable, and maintains a predetermined positional relationship with respect to the upper surface of the document table 111 to provide a double-sided automatic document feeder (RADF). ) 112 is mounted.
[0022]
The double-sided automatic document feeder 112 first transports a document so that one side of the document faces the image reading unit 110 at a predetermined position on the document table 111, and after the image reading on this one side is completed, The document is reversed and conveyed toward the document table 111 so that the other surface faces the image reading unit 110 at a predetermined position on the document table 111. Then, the duplex automatic document feeder 112 executes a duplex conveyance operation for one document. Such operations of document conveyance and reversing the front and back are controlled in relation to the operation of the entire copying machine.
[0023]
The image reading unit 110 is disposed below the document table 111 in order to read an image of the document conveyed on the document table 111 by the double-sided automatic document feeder 112. As shown in FIGS. 1 and 6, the image reading unit 110 transmits a power to the scanning optical system 117 that scans an original, a driving pulley 119 that drives the scanning optical system 117 with a wire 118, and the driving pulley 119. A power transmission system 120 is included. The scanning optical system 117 includes document scanning bodies 113 and 114 that reciprocate in parallel along the lower surface of the document table 111, an optical lens 115, and a CCD line sensor 116 that is a photoelectric conversion element.
[0024]
The document scanning bodies 113 and 114 are composed of a first scanning unit 113 and a second scanning unit 114. The first scanning unit 114 includes an exposure lamp that exposes the surface of the document and a first mirror that deflects a reflected light image from the document in a predetermined direction, and maintains a certain distance from the lower surface of the document table 111. The reciprocation is performed in parallel with the document table 111 at a predetermined scanning speed. The second scanning unit 114 includes a second mirror and a third mirror that further deflect the reflected light image from the original deflected by the first mirror of the first scanning unit 113 in a predetermined direction. It moves back and forth in parallel to the document table 111 while maintaining a constant speed relationship.
[0025]
The optical lens 115 reduces the reflected light image from the original deflected by the third mirror of the second scanning unit, and forms the reduced light image at a predetermined position on the CCD line sensor 116.
[0026]
The CCD line sensor 116 photoelectrically converts the formed light image sequentially and outputs it as an electrical signal. The CCD line sensor 116 is a three-line color CCD capable of reading a black and white image or a color image and outputting line data separated into R (red), G (green), and B (blue) color components. . The document image information converted into an electrical signal by the CCD line sensor 116 is transferred to an image processing unit (not shown), and predetermined image data processing is performed in the image processing unit.
[0027]
Below the image forming station 210, recording sheets (for example, recording media such as plain paper and OHP paper) P serving as transfer media stacked and accommodated in the paper tray TR are separated one by one to the image forming station 210. A paper feeding mechanism 211 that supplies the paper is provided. The sheets P separated and supplied one by one are conveyed to the image forming station 210 with timing controlled by a pair of registration rollers 212 arranged in front of the image forming station 210. Further, the paper P on which an image is formed on one side is supplied and conveyed again to the image forming station 210 in synchronization with the image formation of the image forming station 210.
[0028]
A transfer conveyance belt mechanism 213 as a transfer conveyance carrier unit is disposed below the image forming station 210. The transfer / conveying belt mechanism 213 conveys the sheet P by electrostatically adsorbing the sheet P onto a transfer / conveying belt 216 as a transfer / conveying carrier stretched between the driving roller 214 and the driven roller 215 so as to extend substantially in parallel. It has a configuration. A pattern image detection unit 300 that detects a test pattern formed on the transfer conveyance belt 216 is provided in the vicinity of the lower side of the rotation path of the transfer conveyance belt 216.
[0029]
Further, a fixing device 217 for fixing the toner image transferred and formed on the paper P on the paper P is disposed in the vicinity of the driving roller 214 on the downstream side of the transfer and transport belt mechanism 213 in the paper transport path. ing. The paper P that has passed through the nip portion between the pair of rollers of the fixing device 217 passes through the transport direction switching gate 218 and is discharged onto the paper discharge tray 220 attached to the side wall of the copier body 1 by the discharge roller 219. Is done.
[0030]
The switching gate 218 selectively switches the conveyance path of the paper P after fixing between a path for discharging the paper P to the copier body 1 and a path for resupplying the paper P toward the image forming station 210. Is. The paper P whose transport direction has been switched to the image forming station 210 again by the switching gate 218 is reversed from the front to the back through the switchback transport path 221 and then supplied again to the image forming station 210.
[0031]
Further, above the transfer conveyance belt 216 in the image forming station 210, the first image formation station Pa, the second image formation station Pb, the third image formation station Pc, and the fourth image are adjacent to the transfer conveyance belt 216. The forming stations Pd are provided in order from the upstream side to the downstream side of the sheet conveyance path.
[0032]
The transfer conveyance belt 216 is frictionally driven by the driving roller 214 in the direction indicated by the arrow Z in FIG. 1, holds the paper P fed through the paper feed mechanism 211 as described above, and holds the paper P in the image forming station Pa. To Pd sequentially. Each of the image stations Pa to Pd has substantially the same configuration. The image stations Pa, Pb, Pc, and Pd respectively include photosensitive drums 222a, 222b, 222c, and 222d that are driven to rotate in the direction of arrow F shown in FIG. These four photosensitive drums 222a to 222d have the same outer diameter and length.
[0033]
Around the photosensitive drums 222a to 222d, chargers 223a, 223b, 223c, and 223d for uniformly charging the photosensitive drums 222a to 222d, and electrostatic latent images formed on the photosensitive drums 222a to 222d, respectively. Developing devices 224a, 224b, 224c, and 224d for developing the toner images, transfer discharge devices 225a, 225b, 225c, and 225d for transferring the developed toner images on the photosensitive drums 222a to 222d onto the paper P, and the photosensitive drums Cleaning devices 226a, 226b, 226e, and 226d for removing the toner remaining on 222a to 222d are sequentially arranged along the rotation direction (arrow) of the photosensitive drums 222a to 222d.
[0034]
Laser beam scanner units 227a, 227b, 227c, and 227d are provided above the photosensitive drums 222a to 222d, respectively. The laser beam scanner units 227a to 227d include a semiconductor laser element (not shown) that emits dot light modulated according to image data, and a polygon mirror (deflection) for deflecting the laser beam from the semiconductor laser element in the main scanning direction. Device) 240, and an fθ lens 241 and mirrors 242, 243 for forming an image of the laser beam deflected by the polygon mirror 240 on the surfaces of the photosensitive drums 222a to 222d, respectively.
[0035]
The laser beam scanner 227a has a pixel signal corresponding to the black component image of the color original image, the laser beam scanner 227b has a pixel signal corresponding to the cyan component image of the color original image, and the laser beam scanner 227c has a color original image. The pixel signal corresponding to the magenta color component image is input to the laser beam scanner 227d, and the pixel signal corresponding to the yellow color component image of the color original image is input to the laser beam scanner 227d.
[0036]
As a result, electrostatic latent images corresponding to the color-converted document image information are formed on the respective photosensitive drums 222a to 222d. The developing device 224a contains black toner, the developing device 224b contains cyan toner, the developing device 224c contains magenta toner, and the developing device 224d contains yellow toner. The electrostatic latent images on the photoconductive drums 222a to 222d are developed with these color toners. As a result, the document image information color-converted by the image forming station 210 is reproduced as a toner image of each color.
[0037]
Further, a sheet suction (brush) charger 228 is provided between the first image forming station Pa and the sheet feeding mechanism 211. The charger 228 charges the surface of the transfer conveyance belt 216, and the sheet P supplied from the paper feed mechanism 211 is securely adsorbed on the transfer conveyance belt 216, and then the first image forming station Pa starts the first transfer. The four-image forming station Pd is conveyed without shifting.
[0038]
On the other hand, a static eliminator (not shown) is provided almost directly above the drive roller 214 between the fourth image forming station Pd and the fixing device 217. An AC current for separating the sheet P electrostatically attracted to the transport belt 216 from the transfer transport belt 216 is applied to the static eliminator.
[0039]
In this digital color copying machine, cut sheet-shaped plain paper is used as the paper P. When the paper P is fed from the paper feed cassette and supplied into the guide of the paper feed conveyance path of the paper feed mechanism 211, the leading end portion of the paper P is detected by a sensor (not shown) and output from this sensor. Based on the detected signal, the pair of registration rollers 212 are temporarily stopped.
[0040]
Next, the paper P is fed onto the transfer conveyance belt 216 rotating in the direction of the arrow Z in FIG. 1 at the timing of each of the image stations Pa to Pd. At this time, the transfer and conveyance belt 216 is charged by the charger 228 as described above, so that the paper P is stably conveyed and supplied while passing through the image stations Pa to Pd. .
[0041]
In the image stations Pa to Pd, toner images of the respective colors are formed and superimposed on the support surface of the paper P that is electrostatically attracted and conveyed by the transfer conveyance belt 216. When the transfer of the image by the fourth image station Pd is completed, the paper P is sequentially peeled off from the transfer conveyance belt 216 from the leading end portion thereof by the discharger for discharging, and is guided to the fixing device 217.
[0042]
Finally, the paper P on which the toner image is fixed is discharged onto a paper discharge tray 220 from a paper discharge port (not shown). In the above description, optical writing is performed on the photosensitive drums 222a to 222d by performing exposure by scanning the laser beams with the laser beam scanner units 227a to 227d.
[0043]
Note that a writing optical system (LED head) including a light emitting diode array and an imaging lens array may be used instead of the laser beam scanner unit. The LED head is smaller than the laser beam scanner unit and has no moving parts and is silent. Therefore, it can be suitably used in an image forming apparatus such as a tandem digital color copying machine that requires a plurality of optical writing units.
[0044]
Next, as shown in FIG. 2, the transfer conveyance belt mechanism 213 as a transfer conveyance carrier unit has its conveyance direction changed for each unit.
[0045]
That is, in the transfer conveyance belt mechanism 213, the downstream drive roller 214 is driven on the upstream side with respect to the conveyance direction (the direction indicated by the thick arrow in FIG. 2) of the recording paper (here, plain paper) P as a transfer medium. The central axis of the driving roller 214 and the central axis of the driven roller 215 are displaced in the clockwise direction so as to be displaced by a certain length to the right side of the roller 215.
[0046]
The reason for this is that this digital color copying machine D shipped with the four photoconductor drums 222a to 222d and the four laser beam scanner units 227a to 227d in the image forming station 210 in an optimally adjusted state. ₁ When the image was formed on the desired floor as it was, it was found that no color misregistration appeared in the sub-scanning direction and that a color misregistration of length L as shown in FIG. 8 appeared only in the main scanning direction. It is.
[0047]
That is, the degree of displacement between the central axis of the driving roller 214 and the central axis of the driven roller 215 in FIG. 2 is determined by the image station Pa (K) located upstream and the image station Pd (Y) located downstream. The length is L (mm) with respect to the center-to-center distance D (mm) on the transport surface.
[0048]
When the transfer conveyance belt mechanism 213 in which the central axis of the driving roller 214 and the central axis of the driven roller 215 are displaced in this way is used, a T-shaped image as shown in FIG. It was. This image had no color shift and slight distortion was recognized in the main scanning direction of the image.
[0049]
When the width of the T-shaped image is b (mm) and the distortion is e (mm), there is a relationship of e = (b / D) L, and the transfer conveyance belt mechanism 213 with D = 315 mm and L = 0.2 mm. When the image width b was measured, it was found that b = 3.15 mm. Therefore, e = (b / D) L = (3.15 / 315) × 0.2 = 0.002 mm, but the ratio (percentage) of distortion e to the width b of the image is (e / b) × 100 = 0.002 ÷ 3.15 × 100≈0.63%, which was almost unnoticeable.
[0050]
Here, in the transfer conveyance belt mechanism 213, in order to displace the central axis of the driving roller 214 and the central axis of the driven roller 215 as described above, specifically, the configuration is as follows.
[0051]
That is, as shown in FIG. 3, a fulcrum 302 serving as a rotation center (pivot) of rotation (pivot) for changing the conveyance direction of the transfer conveyance belt mechanism 213 is provided outside the transfer conveyance belt mechanism frame 301. At the same time, an adjustment screw 303 as an action point portion for performing adjustment for changing the transport direction is provided via the base frame 304. At this time, the distance D between the centers of the fulcrum part 302 and the adjustment screw 303 (which becomes the radius of rotation at the time of pivoting) D is set to the image station Pa (K) located on the most upstream side and the image located on the most downstream side. It was made the same as the center distance D on the conveyance surface with the station Pd (Y). Then, the adjustment screw 303 was tightened or loosened, and the mechanism frame 301 was pivoted about the fulcrum portion 302 to obtain a desired displacement.
[0052]
In FIG. 3, reference numeral 305 denotes a timing belt for the driving roller 214, and 306 denotes a driving motor 306 for the timing belt 305. Reference numeral 307 denotes a bearing for receiving the central axis of the driven roller 215, and 308 is disposed between the mechanism frame 301 and the base frame 304 at a position facing the adjustment screw 303 and coaxial with the adjustment screw 303. A compression spring for pivoting the mechanism frame 301 by adjusting the adjustment screw 303 is shown.
[0053]
Embodiment 2
As shown in FIG. 4, a digital color copying machine D which is an image forming apparatus according to Embodiment 2 of the present invention. ₂ The digital color copying machine D according to the first embodiment ₁ Instead of the transfer / conveying belt mechanism 213, an intermediate transfer belt mechanism 213 as an intermediate transfer carrier unit is provided.
[0054]
The intermediate transfer belt mechanism 213 includes a drive roller 214, a driven roller 215, and an intermediate transfer belt 216 as an intermediate transfer carrier stretched between them. The intermediate transfer belt 216 is a digital color copying machine D according to the first embodiment. ₁ It also functions as a transfer medium replacing the recording paper P in
[0055]
This digital color copier D ₂ The positions of the fixing device 217, the conveyance direction switching gate 218, the discharge roller 219, and the discharge tray 220 are the digital color copying machine D according to the first embodiment. ₁ However, the configuration of the image reading unit 110 and the first image forming station Pa to the fourth image forming station Pd is basically the digital color copying machine D according to the first embodiment. ₁ It is the same.
[0056]
Next, as shown in FIG. 5, in the intermediate transfer belt mechanism 213 as an intermediate transfer carrier unit, the conveyance direction is changed for each unit.
[0057]
That is, the intermediate transfer belt mechanism 213 is driven by the center axis of the drive roller 214 so that the downstream drive roller 214 is displaced to the right by a certain length from the upstream driven roller 215 in the transport direction. The central axis of the roller 215 is displaced in the clockwise direction when viewed from above. The reason is that the digital color copying machine D according to Embodiment 1 ₁ It is the same as the case of.
[0058]
Here, in the intermediate transfer belt mechanism 213, in order to displace the central axis of the driving roller 214 and the central axis of the driven roller 215 as described above, specifically, the configuration is as follows.
[0059]
That is, as shown in FIG. 5, a fulcrum portion 402 serving as a rotation center (pivot) of rotation (pivot) for changing the conveyance direction of the intermediate transfer belt mechanism 213 is provided outside the intermediate transfer belt mechanism frame 401. In addition, an eccentric cam 403 serving as an action point portion for performing adjustment for changing the transport direction is provided between the mechanism frame 401 and the base frame 404. At this time, the distance D between the centers of the fulcrum part 402 and the eccentric cam 403 in the sub-scanning direction (which becomes the rotational radius at the time of pivoting) D is the image station Pa (K) located on the most upstream side and the image located on the most downstream side. It was made the same as the center distance D on the conveyance surface with the station Pd (Y). Then, by rotating the eccentric cam 403 around the eccentric shaft and fixing it at an appropriate position, the mechanism frame 401 is pivoted about the fulcrum portion 402 as a pivot, thereby obtaining a desired displacement.
[0060]
In FIG. 5, reference numeral 405 denotes a timing belt for the driving roller 214, and reference numeral 406 denotes a driving motor 306 for the timing belt 405. Reference numeral 407 denotes a bearing for receiving the central axis of the driven roller 215. Reference numeral 408 denotes a mechanism disposed between the mechanism frame 401 and the base frame 404 at a position opposite to the eccentric cam 403. The mechanism is adjusted by adjusting the eccentric cam 403. A compression spring for pivoting the frame 401 is shown.
[0061]
【The invention's effect】
The color image forming apparatus according to claim 1 of the present invention is a tandem type color image forming apparatus in which a plurality of image forming stations are arranged so as to face a transfer path of a transfer medium. Or an intermediate transfer carrier unit; Either one A fulcrum part provided in the unit; Provided in one of the units, And an action point portion that performs adjustment for changing the conveyance direction, Said Transfer carrier unit or Said The intermediate transfer carrier unit is displaced parallel to the main scanning direction so as to change the transfer conveyance carrier or the transfer direction of the intermediate transfer carrier. Said Depending on the point of action The transfer conveyance carrier unit or the intermediate transfer carrier unit is pressed parallel to the main scanning direction. The fulcrum portion is provided so as to be rotatable.
Therefore, by aligning the transfer medium conveyance direction with the image where the color misregistration occurred, the color misregistration can be simplified without adjusting the position of each image forming station and the image forming timing over a long period of time as in the past. Therefore, it is possible to eliminate the color misregistration and form a good image. In addition, the structure of the color image forming apparatus does not need to be strengthened more than necessary, and a tandem type image forming apparatus can be realized at low cost and low weight.
[0062]
In the color image forming apparatus according to claim 2 of the present invention, A recording sheet as a transfer medium is transferred and conveyed by the transfer conveyance carrier, and color shift adjustment in the main scanning direction is performed by changing the conveyance direction of the transfer conveyance carrier. It is comprised so that it may be performed.
Therefore, it is possible to easily change the conveyance direction of the recording paper by changing the conveyance direction of the transfer conveyance carrier, and without adjusting the position of each image forming station and the image formation timing over a long time as in the past. Therefore, it is possible to easily eliminate the color misregistration, and it is possible to perform good image formation without color misregistration.
[0063]
In the color image forming apparatus according to claim 3 of the present invention, Color shift adjustment in the main scanning direction is possible by changing the transport direction of the intermediate transfer carrier that is the transfer medium. It is comprised so that it may be performed.
Therefore, by changing the transport direction of the intermediate transfer carrier, it is possible to superimpose the color on the intermediate transfer carrier so that there is no color misregistration. Therefore, it is possible to easily eliminate the color misregistration without making any adjustments, and it is possible to form a good image without color misregistration.
[0064]
In the color image forming apparatus according to claim 4 of the present invention, The transfer conveyance carrier unit includes a transfer conveyance carrier, a drive roller, and a driven roller, and the intermediate transfer carrier unit includes an intermediate transfer carrier, a drive roller, and a driven roller. It is characterized by that.
Therefore, by adjusting the transport direction of the transfer transport carrier unit or the intermediate transfer carrier unit, the transport direction can be adjusted while maintaining a good transport state of the transfer transport carrier or intermediate transfer carrier. Thus, simple color misregistration adjustment can be performed accurately and easily.
[0065]
In the color image forming apparatus according to claim 5 of the present invention, The fulcrum part and the action point part The distance in the sub-scanning direction is the same as the distance between the image forming stations at both ends of the plurality of image forming stations.
Accordingly, the adjustment amount in the conveyance direction of the transfer conveyance carrier unit or the intermediate transfer carrier unit and the color misregistration amount of the images by the image forming stations at both ends coincide with each other, so that the adjustment can be easily performed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating the overall configuration of a digital color copying machine according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram illustrating a configuration of a transfer conveyance belt mechanism in the color copying machine of FIG. 1;
FIG. 3 is an explanatory diagram illustrating a method for adjusting the transfer / conveying belt mechanism shown in FIG. 2;
FIG. 4 is an explanatory diagram illustrating the overall configuration of a digital color copying machine according to a second embodiment of the present invention.
FIG. 5 is an explanatory diagram illustrating a method for adjusting an intermediate transfer belt mechanism in the color copying machine shown in FIG. 4;
FIG. 6 is a front view showing an installation state of a conventional digital color copying machine.
7 is a perspective view of a transfer conveyance belt mechanism and an image forming station in the digital color copying machine of FIG. 6. FIG.
8 is an explanatory diagram illustrating a color shift of an image on a recording sheet after passing through a transfer conveyance belt mechanism in the digital color copying machine of FIG.
[Explanation of symbols]
1 Digital color copier (color image forming device)
P Recording paper (transfer medium)
210 Image forming station
213 transfer conveyance belt mechanism (transfer conveyance carrier unit),
Intermediate transfer belt mechanism (intermediate transfer carrier unit)
214 Driving roller
215 Followed roller
216 transfer conveyance belt (transfer conveyance carrier),
Intermediate transfer belt (intermediate transfer carrier, transfer medium)
302 fulcrum
303 Adjustment screw (action point)
402 fulcrum
403 Eccentric cam (action point)

Claims (5)

In a tandem type color image forming apparatus in which a plurality of image forming stations are arranged so as to face a conveyance path of a transfer medium,
A transfer conveyance carrier unit or an intermediate transfer carrier unit, and a fulcrum portion provided in one of the units, provided in one of the units, and a force output portion to adjust for changing the conveying direction Have
The transfer conveyance carrier unit or the intermediate transfer carrier unit, to vary the conveying direction of the transfer conveyance carrier or intermediate transfer carrier, the transfer conveyance carrier by the force output portion parallel displaced in the main scanning direction A color image forming apparatus, wherein the unit or the intermediate transfer carrier unit is pressed in parallel with a main scanning direction so as to be able to rotate around the fulcrum portion. The recording paper as a transfer medium is transferred and conveyed by the transfer conveyance carrier, and color misregistration adjustment in the main scanning direction is performed by changing the conveyance direction of the transfer conveyance carrier. The color image forming apparatus according to claim 1. 2. The color image forming apparatus according to claim 1, wherein the color misregistration adjustment in the main scanning direction is performed by changing a conveyance direction of the intermediate transfer carrier as a transfer medium . The transfer conveyance carrier unit comprises a transfer conveyance carrier, a drive roller and a driven roller, and the intermediate transfer carrier unit comprises an intermediate transfer carrier, a drive roller and a driven roller. The color image forming apparatus according to 1. 5. The color image formation according to claim 4, wherein a distance between the fulcrum part and the action point part in the sub-scanning direction is the same as a distance between the image forming stations at both ends of the plurality of image forming stations. apparatus.

Images