JP2001100543A - Belt control method, belt controller and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt control method, a belt controller and an image forming device by which color slurring is restrained and the quality of a color image is improved. SOLUTION: The color slurring of the color image formed on an image recording medium 14 is corrected by providing a transfer belt 13 having image forming layers 13a in which particulates to form an image by moving by electrophoretic action are dispersed at both ends, photoreceptor drums 11Y, 11M, 11C and 11K applying electrostatic force corresponding to the specified image to the image forming layer 13a of the traveling transfer belt 13, a registration mark detection means 16 measuring a particulate image formed on the image forming layer 13a by the applied electrostatic force in an image forming part 2, and a controller 22 controlling the write timing of image data with a laser beam based on the measured result of the particulate image in the image forming part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt control method, a belt control device, and an image forming apparatus for an image forming apparatus used in an electrophotographic color copying machine, a color printer, and the like.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic image forming apparatus, toner images of different colors are formed on respective photosensitive drums, and these toner images are formed on a transfer medium such as a recording paper or an intermediate transfer belt. To obtain a color image
A so-called tandem type image forming apparatus is known.

FIG. 10 is a schematic configuration diagram of a conventional image forming apparatus for sequentially transferring toner images of each color onto recording paper to obtain a color image.

[0004] The image forming apparatus 100 shown in FIG. 10 has a configuration in which yellow (Y), magenta (M), cyan (C), and yellow (Y) obtained by processing red, green, and blue color data.
Exposure units 111Y and 111 having rotary polygon mirrors and the like for deflecting light emitted from a laser light source (not shown) that emits laser light modulated based on black (K) image data.
M, 111C and 111K are provided. The image forming apparatus 100 is charged by a charger (not shown) and is exposed to the above-mentioned exposure units 111Y, 111M, 111C, and 11C.
The photosensitive drums 112 </ b> Y and 112 </ b> Y that form an electrostatic latent image on the surface by rotating while receiving laser light exposure from 1 K
12M, 112C, 112K, and their photosensitive drums 1
Developing units 113Y, 113M, 113C and 113K are provided for developing the electrostatic latent images formed on 12Y, 112M, 112C and 112K with Y, M, C and K toners, respectively. Further, the image forming apparatus 100 includes a driving roll 121 and driven rolls 122, 123, and 124.
And the driving roll 121 and the driven rolls 122 and 12
The transfer belt 130 stretched between the transfer belts 3 and 124, the registration roll 160 for feeding out the recording paper 150 in the paper tray 140 at a predetermined timing, and the photosensitive drums 112 </ b> Y and 112 </ b> Y.
Cleaners 114Y, 114M, 114C, 114K for removing residual toner on 112M, 112C, 112K
And a fixing device 170 for fixing the toner image transferred onto the recording paper 150.

[0005] The image forming apparatus 100 configured as described above.
First, after the yellow photosensitive drum 112Y is uniformly charged, a laser beam modulated based on the yellow image data is emitted from the exposure unit 111Y, and the photosensitive drum 112Y is exposed. Photoconductor drum 11
An electrostatic latent image for yellow is formed on the 2Y surface. The electrostatic latent image is developed by a developing unit 113Y to form a yellow toner image, and is sent out at a predetermined timing by a registration roll 160, carried on a transfer belt 130, and conveyed on a recording paper 150 conveyed in the direction of arrow A. Transcribed. On the yellow toner image transferred onto the recording paper 150, the magenta toner image formed on the next photosensitive drum 112M is transferred so as to be superimposed thereon, and further, cyan and black are further placed thereon. Are transferred so as to overlap each other. The color toner image formed by superimposing the four color toner images in this manner is
The image is fixed by 70 to complete the color image.

[0006] Further, image formation in which a multicolor toner image is formed by sequentially transferring toner images of each color on an intermediate transfer belt, and the multicolor toner images are collectively transferred to recording paper to obtain a color image. Devices are also known.

FIG. 11 is a schematic configuration diagram of a conventional image forming apparatus for sequentially transferring toner images of each color onto an intermediate transfer belt to obtain a color image.

The same components as those of the image forming apparatus 100 shown in FIG.

The image forming apparatus 200 shown in FIG.
0 in comparison with the image forming apparatus 100 shown in FIG.
0 is replaced by the intermediate transfer belt 210;
The photosensitive drums 112Y, 112Y,
The difference is that primary transfer rolls 211Y, 211M, 211C, 211K are arranged at positions facing 112M, 112C, 112K, and that secondary transfer rolls 212 are added.

In this image forming apparatus 200, the intermediate transfer belt 210 is moved in the direction of arrow B by the rotation of the driving roll 121, and the toner of each color on the photosensitive drums 112Y, 112M, 112C, 112K is placed on the intermediate transfer belt 210. The image is sequentially transferred to the intermediate transfer belt 2.
The four color toner images are transferred onto the recording paper 150 in a superimposed manner, and are collectively transferred onto the recording paper 150 by the secondary transfer roll 212. The color toner image formed by superimposing the four color toner images in this manner is fixed by the fixing device 170 to complete the color image.

In the above-described image forming apparatuses 100 and 200, it is important to accurately overlap the toner images of the respective colors on the photosensitive drums in order to prevent image unevenness and color shift. Therefore, a rotation detector such as a rotary encoder is attached to a roll on which a belt (transfer belt or intermediate transfer belt) is stretched, and based on the detection result of the rotation detector,
It has been practiced to control the speed of the belt by controlling the motor that drives the belt.

FIG. 12 is a diagram showing a configuration of a motor control device in an image forming apparatus proposed in Japanese Patent Application Laid-Open No. 62-290374.

FIG. 12 shows a drive roll 301, driven rolls 302 and 303, and a transfer belt 304 wound around the drive roll 301 and the driven rolls 302 and 303 and moved in the direction of arrow C by the rotation of the drive roll 301. And the motor control device 310 are shown. Marks 304a are formed on the transfer belt 304 at predetermined intervals on the side edges of the transfer belt 304. Further, the motor control device 310 has a C for reading the mark 304a.
A reader 311 such as a CD, a control board 312 on which a control circuit is mounted, and a motor 313 for driving the drive roll 301 at a speed according to a command from the control circuit are provided. The motor control device 310 reads the mark 304a by the reader 311 and controls the rotation of the motor 313 based on the read result to control the speed of the transfer belt 304, thereby preventing color misregistration.

In addition, Japanese Patent Application Laid-Open Nos. 1-142673, 1-142677 and 1-142678.
Japanese Patent Application Laid-Open Nos. JP-A-1-1142681 and JP-A-1-142675 disclose a mark detector for detecting a registration mark of each color formed on a transfer belt, and a detection output from the mark detector. 2. Description of the Related Art An image forming apparatus provided with a controller that controls the speed of a transfer belt based on a signal has been proposed.

FIG. 13 is a schematic configuration diagram of an image forming apparatus for detecting the registration mark and controlling the speed of the transfer belt.

The same components as those of the image forming apparatus 100 shown in FIG.

The image forming apparatus 400 shown in FIG. 13 has a registration mark 1 of each color formed on the transfer belt 130.
30a and an exposure unit 1 based on a detection signal output from the mark detector 401.
A controller 402 for controlling 11Y, 111M, 111C and 111K, and a registration mark 1 formed on the transfer belt 130 and detected by a mark detector 401.
And a cleaner 403 for removing 30a.

In the image forming apparatus 400, a mark detector 401 detects a registration mark of a predetermined reference color and a registration mark of another color, and a controller 402 controls each of the exposure devices 111 based on a relative difference between these detection timing shifts.
The color shift of each color is prevented by controlling the exposure timing of each of the photoconductor drums 112Y, 112M, 112C, and 112K from Y, 111M, 111C, and 111K.

[0019]

However, in the above-described image forming apparatus 400, the toner used to form the registration mark 130a on the transfer belt 130 becomes unnecessary after the detection of the registration mark 130a. A cleaner 403 for removing the toner for the registration mark 130a is required. In addition, registration mark 1
30a or the registration mark 130a
Is frequently performed, the amount of toner used to form the registration mark 130a increases. Here, since the amount of toner that can be stocked in the cleaner 403 is determined by the size of the collecting container, it is necessary to provide a large collecting container and the like. In addition, since the amount of toner previously stored in the developing device is also determined by the size of the developing device, in an image forming apparatus used in a small printer, as described above, a color registration mark is formed with toner on a transfer belt to form a color. It is difficult to apply a technique for preventing displacement.

In a low-cost device such as a desktop printer, a thick metal frame is rarely used as a main body frame as in a general office copying machine or a large printer. Frames are often used. Here, one of the major causes of the color misregistration is that the main body frame of the apparatus is deformed at the time of installation or due to a temperature difference. If the main body frame is deformed, the writing position on the photoconductor by the laser beam is shifted, or the distance between the photoconductors is changed, thereby causing a color shift. Large copiers and printers hardly move once they are installed, but small and low-cost printers such as desktop printers often change their installation locations. When used at home or the like, there are cases where sudden impacts are given and the temperature difference is large. For this reason, the number of times of color misregistration correction in an image forming apparatus used in a small-sized and low-cost printer is much larger than that in an image forming apparatus used in a large-sized printer and the like.
Along with this, the amount of toner removed by the cleaner is further increased,
Therefore, the size of the collection container is further increased, and it is more difficult to suppress color misregistration and improve the quality of a color image.

Also, the above-mentioned Japanese Patent Application Laid-Open No. 62-290374 is described.
In an image forming apparatus provided with a motor control device proposed in Japanese Patent Application Laid-Open Publication No. H10-209, a mark is previously attached to a transfer belt, a mark is read by a reader, and the speed of the transfer belt is controlled based on the read result. Therefore, there is no problem due to the toner removal by the cleaner, and it is possible to correct the color shift caused by the transfer belt.However, it is necessary to prevent the color shift due to the deformation of the frame. It is difficult.

The present invention has been made in view of the above circumstances, and has as its object to provide a belt control method, a belt control device, and an image forming apparatus capable of suppressing color misregistration and improving the quality of a color image.

[0023]

According to the present invention, there is provided a belt control method for controlling the running of a belt running in a predetermined direction, wherein at least a part of the belt to be controlled includes an electrophoretic belt. An image forming layer in which fine particles that move by action to form an image are dispersed, and in a predetermined image forming section, an electrostatic force corresponding to a predetermined image is applied to the image forming layer of the running belt. Forming a fine particle image on the image forming layer, and measuring the fine particle image formed on the image forming layer in an image measuring section on the downstream side of the belt in the running direction of the belt from the image forming section. The traveling direction of the belt is controlled based on the measurement result of the fine particle image in the section.

Further, the belt control apparatus of the present invention for achieving the above object has an endless shape having an image forming layer circulating and running in a predetermined direction and having at least a part of which is dispersed with fine particles which move by electrophoresis to form an image. A belt, in a predetermined image forming unit, electrostatic force applying means for forming a fine particle image on the image forming layer by applying an electrostatic force corresponding to a predetermined image to the image forming layer of the running belt, In the image measuring section on the downstream side in the running direction of the belt from the image forming section, an image measuring means for measuring the fine particle image formed on the image forming layer, and based on the measurement result of the fine particle image in the image forming section. And a belt control means for controlling the running direction of the belt.

Further, the image forming apparatus according to the present invention, which achieves the above object, comprises a plurality of photoconductors on which an electrostatic latent image is formed while rotating, and a plurality of photoconductors formed on each of the plurality of photoconductors. A developing device for developing the electrostatic latent image with the toner image of each color; and an endless belt circulating along the plurality of photoconductors, the predetermined belt being carried directly or on the belt. A belt for receiving the transfer of the plurality of toner images formed on the plurality of photoconductors in sequence according to the movement of the belt on the image recording medium, and finally fixing the image on the predetermined image recording medium An image forming apparatus for forming a color image based on the formed toner image, wherein the belt has, at least in part, an image forming layer in which fine particles that move by electrophoresis to form an image are dispersed. A forming unit configured to form a mark latent image on the surface of the photoreceptor corresponding to a mark for detecting misregistration, wherein the photoreceptor reduces an electrostatic force caused by the mark latent image formed on the surface; Applying a mark to the image forming layer of the belt by the fine particles by applying the mark to the image forming layer, and further detecting the mark formed on the image forming layer on the belt by the image forming apparatus. It is characterized by having mark detection means.

Here, the belt forms the image forming layer,
It is preferable to have the belt at both ends in the width direction crossing the running direction of the belt.

In a preferred embodiment, the apparatus further comprises control means for controlling a timing of forming an electrostatic latent image on the photosensitive member based on a mark detection result by the mark detection means.

Further, a control means for controlling the rotation speed of the photoconductor based on the mark detection result by the mark detection means may be provided.

[0029] Further, a control means for controlling the moving speed of the belt based on the mark detection result by the mark detection means may be provided.

Further, a control means for controlling meandering of the belt based on a mark detection result by the mark detection means may be provided.

Further, there is provided control means for controlling the inclination of the photosensitive member with respect to the belt or the inclination of the formation of an electrostatic latent image formed on the photosensitive member based on the mark detection result by the mark detecting means. You may.

[0032]

Embodiments of the present invention will be described below.

FIG. 1 is a schematic structural view of an image forming apparatus according to a first embodiment of the present invention.

The image forming apparatus 10 shown in FIG. 1 has a photosensitive drum 11Y on which an electrostatic latent image is formed while rotating.
11M, 11C, and 11K, and each photosensitive drum 11Y, 1
Developing units 12Y, 12M, 12 for developing the electrostatic latent images formed on 1M, 11C, 11K with toner images of respective colors;
C, 12K, and the photosensitive drums 11Y, 11M, 11C,
An endless belt circulating along 11K,
On a predetermined image recording medium 14 carried on the belt,
The four photosensitive drums 11Y, 11M, 11C, and 11K formed on the four photosensitive drums 11Y, 11M, 11C, and 11K are sequentially moved according to the movement of the belt.
A transfer belt 13 that receives the transfer of the three toner images,
Finally, a color image is formed by the fixed toner image on the predetermined image recording medium 14.

The transfer belt 13 has, at least in part, an image forming layer 13a in which fine particles moving by electrophoresis to form an image are dispersed.

The image forming apparatus 10 also includes an exposure unit 1 for forming a mark latent image corresponding to a mark for detecting a positional shift on the surface of the photosensitive drums 11Y, 11M, 11C, and 11K.
5Y, 15M, 15C, and 15K (corresponding to a mark latent image forming unit of the image forming apparatus of the present invention).

Further, the photosensitive drums 11Y, 11M, 1
1C and 11K apply an electrostatic force generated by a mark latent image formed on the surface to the image forming layer 13a of the transfer belt 13 so that the resist mark 13b of fine particles is formed on the image forming layer 13a.
And the image forming apparatus 1
Reference numeral 0 denotes a registration mark detecting means 16 for detecting a registration mark 13b formed on the image forming layer 13a on the transfer belt 13.

The image forming apparatus 10 includes a driving roll 17_1 for driving the transfer belt 13 and driven rolls 17_2, 17_3, 17_4, and a registration roll 19 for feeding out the image recording medium 14 in the paper tray 18 at a predetermined timing. , Photoreceptor drums 11Y, 11M, 11
C, cleaner 20Y for removing residual toner on 11K,
20M, 20C, and 20K, and a fixing device 21 for fixing the toner image transferred onto the image recording medium 14.

Further, the image forming apparatus 10 detects the photosensitive drums 11Y, 11M, 11C, 11C based on the result of the registration mark detection by the registration mark detecting means 16.
A controller 22 (corresponding to control means according to the present invention) for controlling the timing of forming an electrostatic latent image on K is provided.

The transfer belt 13 and the photosensitive drum 11
The Y, 11M, 11C, and 11K, the registration mark detecting means 16, and the controller 22 correspond to a belt control device according to the present invention. Hereinafter, description will be made with reference to FIG.

FIG. 2 is a schematic perspective view of the image forming apparatus shown in FIG. 1 including a belt control device.

In this image forming apparatus 10, as shown in FIG. 2, the transfer belt 13 has the image forming layer 13a at both ends in the width direction crossing the running direction of the transfer belt 13.
Further, the belt control device 1 constituting the image forming apparatus 10
In other words, in the description of the image forming apparatus 100 shown in FIG. 1, in other words, an endless endless image forming layer 13 a circulating in a predetermined direction and having at least a part of which is dispersed by an electrophoretic action and which forms an image by forming an image is dispersed. Transfer belt 13
Transfer belt 1 running in a predetermined image forming unit 2
The photosensitive drums 11Y, 1 as electrostatic force applying means for forming a fine particle image on the image forming layer 13a by applying an electrostatic force corresponding to a predetermined image to the third image forming layer 13a.
1M, 11C, and 11K, and a registration mark detecting unit 16 (in the present invention) for measuring a fine particle image formed on the image forming layer 13a in the image measuring unit 3 downstream of the image forming unit 2 in the traveling direction of the transfer belt 13. A controller 22 that controls the traveling direction of the transfer belt 13 via the drive motor 4 based on the measurement result of the fine particle image in the image forming unit 2 (corresponding to an image measuring unit of the belt control device) (the belt control device of the present invention) ). The belt control device 1 employs an example of a belt control method according to the present invention. The belt control method according to the example is a belt control method that controls the traveling of a transfer belt 13 traveling in a predetermined direction. Transfer belt 13 has, at least in part, an image forming layer 13 a in which fine particles that move to form an image by electrophoretic action are dispersed.
An electrostatic force corresponding to a predetermined image is applied to the image forming layer 13a to form a fine particle image on the image forming layer 13a. 3, the fine particle image formed on the image forming layer 13 a is measured by the electrostatic force applied in the image forming unit 3, and based on the measurement result of the fine particle image in the image forming unit 2, the traveling direction of the transfer belt 13 is measured. Is a method of controlling

Further, the exposure units 15Y, 15M,
15C and 15K are laser beams modulated based on image data of yellow (Y), magenta (M), cyan (C), and black (K) obtained by processing red, green, and blue color data. Polygon mirrors 15a, 15 that deflect light emitted from a laser light source (not shown) that emits light.
5b, 15c, and 15d.

The image forming apparatus 10 having the built-in belt controller 1 has the respective photosensitive drums 11Y and 11Y.
This is a so-called tandem-type image forming apparatus that forms toner images of different colors on M, 11C, and 11K, respectively, and sequentially transfers these toner images to the image recording medium 14 to obtain a color image.

The flow of image formation in the image forming apparatus 10 of the present embodiment is the same as the flow of image formation in the conventional image forming apparatus 100 shown in FIG. On the other hand, the flow of forming the registration mark 13b is different from the flow of forming an image described above, and the photosensitive drums 11Y, 11M,
The electrostatic latent images formed for the registration marks 13b on 11C and 11K are not developed. The writing area of the photoconductor drums 11Y, 11M, 11C, and 11K by the laser light is the photoconductor drums 11Y, 11M, 11C, and 1K.
The electrostatic latent image of the registration mark 13b formed on the photosensitive drums 11Y, 11M, 11C, and 11K has a design value longer than the development area in the axial direction of 1K. The image is transferred to the image forming layer 13a. The term “transfer” herein refers to moving fine particles in the dispersion liquid of the image forming layer 13 a by an electrostatic latent image.

The movement of fine particles due to the electrophoretic action is a phenomenon discovered in the 1800's, and is described in general physics dictionaries and scientific / technical dictionaries.
Further, Japanese Patent Publication No. 50-15115 discloses an application as a display. In recent years, an electrophoretic display device in which a colored liquid in which TiO2 is dispersed in a capsule made of gelatin or the like is encapsulated to prevent aggregation and sedimentation of particles has been developed. Technical Study Group). In the present embodiment, in the area at the end of the transfer belt 13, the encapsulated fine particle dispersion liquid may be prepared in a layered form, or a layer in which the encapsulated fine particle dispersed liquid is uniformly dispersed without being encapsulated may be prepared. Although not shown, the registration mark 13b
After the detection, by applying an electric field having a polarity opposite to that of the electric field at the time of forming the registration mark 13b, the registration mark 1
Since the fine particles having formed 3b move to the opposite position, the resist mark 13b can be erased from the image forming layer 13a. Therefore, the resist mark 13b formed on the image forming layer 13a can be rewritten, that is, the writing operation and the erasing operation can be repeated, and the color shift can be corrected continuously. Therefore, as in the conventional technology of forming a registration mark using toner, by continuously performing color misregistration correction, toner consumption is large and toner is exhausted despite the fact that the actual number of printed sheets is small. The problem that printing cannot be performed can be prevented.

FIG. 3 is a view showing a state in which an image forming layer is formed on the transfer belt shown in FIG.

Usually, the transfer belt 13 shown in FIG.
A plastic sheet such as T (polyethylene terephthalate) or PI (polyimide) is often used. In the present embodiment, the plastic sheet is provided with a recessed region at the end, and the fine particle dispersion liquid 13_ is formed in this region.
1 and then another plastic film 13_
2 is adhered to the image forming layer 1 with an adhesive 13_3.
3a is manufactured.

FIG. 4 is a view showing how to form an image forming layer different from the image forming layer shown in FIG.

As shown in FIG. 4, the fine particle-dispersed liquid 23_1 is sealed in two plastic sheets 23_2 such as PET or PI to form the image forming layer 23a. Further, the produced image forming layer 23 a is adhered to the transfer belt 23. In this case, the thickness of the end portion of the transfer belt 23 increases, but since the fine particles have a size of sub-um or less, the PET or PI to be encapsulated may be very thin. Since PI and the like can be manufactured even with a sheet of several μm, it is sufficiently possible to reduce the thickness of the image forming layer 23a. Further, since the thickness of a general transfer belt or an intermediate transfer belt is 70 to 125 um, if the entire image forming layer 23a is manufactured to have a thickness of 10 to 20 um, the thickness does not significantly affect image formation. In the case where the thickness is affected, a step may be provided at the end of the transfer belt or the intermediate transfer belt, and a sheet in which the fine particle dispersion liquid is sealed may be fitted therein.

FIG. 5 is a diagram showing a manner of detecting a resist mark formed on the image forming layer.

The electrostatic force of the mark latent image formed on the surface of the photosensitive drum is applied to the image forming layer 13a shown in FIG.
A register mark 13b is formed by 1a. In order to detect the registration mark 13b, light is emitted from the light source 16a constituting the registration mark detection means 16 (see FIG. 2) to the image forming layer 13a, and the reflected light is detected by the light receiving element 16b using a CCD or the like. I do. Here, in the area of the image forming layer 13a where the resist mark 13b is formed, the reflected light is strong, and thus the output of the light receiving element 16b shown in FIG. 5B is large. On the other hand, no resist mark 13b is formed on the image forming layer 13a shown in FIG. 5C, and the light from the light source 16a is absorbed by the image forming layer 13a, so that the intensity of the reflected light is weak. The output of the light receiving element 16b shown in FIG. When the transfer belt 13 is moving, a rectangular pulse signal is output from the light receiving element 16b corresponding to the intensity of the reflected light, and the registration mark 13b is detected.

As described above, the image forming apparatus 10 of the present embodiment
In this example, a transfer belt 13 as a transfer medium is provided with an image forming layer 13a in which fine particles moving by electrophoresis are dispersed, and the fine particles dispersed in the image forming layer 13a generate an electrostatic force (Coulomb force). It is possible to move in the liquid by giving the liquid, so by controlling the static electricity, a contrast is obtained between the color (for example, colored with a dye) of the fine particle-dispersed liquid of the image forming layer 13a and the color of the fine particles. be able to. In the present embodiment, as described above, this electrophoretic action is used for forming the registration mark 13b, and the image forming layer 1 provided on the transfer belt 13 is used.
Each fine particle in the fine particle-dispersed liquid 3a is a photosensitive drum 11
Since the electrostatic latent images formed on Y, 11M, 11C, and 11K are moved by the electrostatic force, the contrast of the registration mark 13b on the transfer belt 13 is obtained. Also,
The fine particles moved by the electrophoresis return to the original state (original position) by giving the opposite polarity electrostatic force.
It can be used repeatedly. In the present embodiment, the registration mark 13b corresponding to each color is detected,
The controller 22 calculates the relative color shift of each color based on these detection results, and further controls the timing of writing the image data with a laser beam based on the results, thereby forming the image data on the image recording medium 14. Correct the color shift of the color image. Therefore, compared with the conventional image forming apparatus, the toner for forming the registration mark is unnecessary,
No cleaner is required to remove the toner.
Further, the consumption of the whole toner can be suppressed, and a large collecting container for collecting the toner is not required, so that the size of the apparatus can be reduced. Therefore, the image quality of a color image can be improved in an image forming apparatus used for a small printer.

FIG. 6 is a schematic perspective view of an image forming apparatus according to a second embodiment of the present invention.

The image forming apparatus 30 shown in FIG. 6 is provided with a controller 32 for controlling the rotation speed on the photosensitive drums 11Y, 11M, 11C, 11K based on the mark detection result by the registration mark detecting means 16. I have. Specifically, the controller 32 transmits the mark detection result by the registration mark detection unit 16 to the photosensitive drum 11.
Y, 11M, 11C, and 11K are fed back to a motor (not shown) to drive the photosensitive drum 1
The rotation speeds of 1Y, 11M, 11C, and 11K are controlled.
Since the change in the rotation speed of the photoconductor drums 11Y, 11M, 11C, and 11K causes a change in the magnification of the image, if the magnification of a certain color is different from the magnification of the other color based on the above detection result, the photoconductor drum is not changed. The magnification can be corrected by adjusting the rotation speed. The exposure units 15Y, 15M,
The same result can be obtained by adjusting the rotation speed of the polygon motor (not shown) provided for 15C and 15K.

FIG. 7 is a schematic perspective view of an image forming apparatus according to a third embodiment of the present invention.

The image forming apparatus 40 shown in FIG. 7 is provided with a controller 42 for controlling the moving speed of the transfer belt 13 based on the mark detection result by the registration mark detecting means 16. When the transfer unevenness occurs in the transfer belt 13, a fluctuation of the transfer belt 13 due to the uneven transfer is detected in the detection result of the registration mark 13 b of each color. In such a case, the controller 42 controls the rotation speed of the drive roll 17_1 that drives the transfer belt 13 via the drive motor 4 so that the transfer belt 1
3 can be suppressed. Since the registration mark 13b corresponding to each color has a different distance between the position to be transferred to the transfer medium and the position of the detection means for each color (each photoconductor drum), the fluctuation component of the transfer belt 13 is different for each registration mark 13b. Is detected with a shift corresponding to the time required to move between photosensitive drums. In other words, by delaying the distance between the photosensitive drums calculated in advance with respect to the detection result, when a large transport unevenness occurs on the transfer belt 13, the unevenness can be detected. By correcting the rotation speed of the drive roll 17_1 for driving the transfer belt 13, it is possible to correct the amount of color shift generated in the transfer system of the transfer belt 13. Particularly noticeable components are a component once per rotation of the transfer belt and a component once per rotation of the drive roll. The former is caused by uneven thickness of the transfer belt, and the latter is uneven conveyance component caused by roll eccentricity.

FIG. 8 is a schematic perspective view of an image forming apparatus according to a fourth embodiment of the present invention.

The image forming apparatus 50 shown in FIG. 8 has a controller 52 for controlling the meandering of the transfer belt 13 based on the mark detection result by the registration mark detecting means 16.
Is provided. When the meandering of the transfer belt 13 is controlled, the meandering of the transfer belt 13 can be corrected by detecting a mark latent image corresponding to the registration mark 13b formed on a specific photosensitive drum. it can. If it is desired to increase the meandering detection accuracy, the distance between the photosensitive drums calculated in advance may be corrected for the detection result, as described with reference to FIG. In order to control the meandering of the transfer belt 13, in the present embodiment, a steering roll 53 that stretches the transfer belt 13 is used.
The tilting amount of the transfer belt 13 is adjusted by changing the tilt angle α. The present invention is not limited to this, but may be any device that controls the meandering of the belt based on the mark detection result by the registration mark detection unit.

FIG. 9 is a schematic perspective view of an image forming apparatus according to a fifth embodiment of the present invention.

In the image forming apparatus 60 shown in FIG. 9, the photosensitive drums 11Y, 11M, 11C, 11K
A controller 62 is provided for controlling the inclination with respect to the transfer belt 13 or the inclination of the electrostatic latent images formed on the photosensitive drums 11Y, 11M, 11C, and 11K. Here, the photosensitive drums 11Y, 11M, 1
The case where the inclination of 1C and 11K with respect to the transfer belt 13 is controlled will be described.

At both ends of the transfer belt 13 shown in FIG. 9, image forming layers 13a are provided.
The inclination of the image can be calculated by detecting the registration mark 13b formed in the image by the registration mark detecting means 16. The image signals for forming the registration marks 13b are sent to the exposure units 15Y, 15M, 15C, 15
K, the photosensitive drums 11Y, 11M, 11C, 1
Forming an electrostatic latent image for the registration mark 13b on 1K,
At this time, the registration mark 13b is detected, and if there is a difference between the detection timings from both ends of the transfer belt 13 as a detection result, the image is formed obliquely, and correction is required. In the present embodiment, the inclination of the image is corrected by adjusting the position of the image forming unit or the position of the exposure unit.

In the present embodiment, an example in which the image forming layers are provided at both ends of the transfer belt has been described. However, the present invention is not limited to this. What is necessary is just to have.

[0064]

As described above, according to the present invention,
Since there is no need to use registration mark toner for correcting color misregistration, a cleaner for removing the toner is unnecessary, and even when performing color misregistration correction continuously, the registration mark toner can be used. No container for collection is required. Therefore, it is possible to reduce the size of the image forming apparatus without deteriorating image quality due to color misregistration. Further, when the image forming apparatus is likely to cause color misregistration, for example, when a plastic frame is used without using metal for the main body frame, or when the environment changes frequently due to a change in the installation location, etc. Also, it is possible to correct the color misregistration and to provide an image forming apparatus having good image quality.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view of the image forming apparatus shown in FIG. 1 including a belt control device.

FIG. 3 is a view showing a state in which an image forming layer is formed on the transfer belt shown in FIG.

FIG. 4 is a view showing a state in which an image forming layer different from the image forming layer shown in FIG. 3 is produced.

FIG. 5 is a diagram illustrating a state in which a resist mark formed on an image forming layer is detected.

FIG. 6 is a schematic perspective view of an image forming apparatus according to a second embodiment of the present invention.

FIG. 7 is a schematic perspective view of an image forming apparatus according to a third embodiment of the present invention.

FIG. 8 is a schematic perspective view of an image forming apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a schematic perspective view of an image forming apparatus according to a fifth embodiment of the present invention.

FIG. 10 is a schematic configuration diagram of a conventional image forming apparatus for sequentially transferring toner images of each color on recording paper to obtain a color image.

FIG. 11 is a schematic configuration diagram of a conventional image forming apparatus that sequentially transfers toner images of each color onto an intermediate transfer belt to obtain a color image.

FIG. 12 is a diagram showing a configuration of a motor control device in an image forming apparatus proposed in Japanese Patent Application Laid-Open No. 62-290374.

FIG. 13 is a schematic configuration diagram of an image forming apparatus that detects a registration mark and controls the speed of a transfer belt.

[Explanation of symbols]

 Reference Signs List 1 belt control device 2 image forming unit 3 image measuring unit 4 drive motor 10, 30, 40, 50, 60 image forming device 11Y, 11M, 11C, 11K photoconductor drum 12Y, 12M, 12C, 12K developing device 13, 23 transfer Belts 13a, 23a Image forming layer 13b Registration mark 13_1, 23_1 Fine particle dispersion liquid 13_1a Fine particles 13_2 Plastic film 13_3 Adhesive 14 Image recording media 15Y, 15M, 15C, 15K Exposure devices 15a, 15b, 15c, 15d Rotating polygon mirror 16 Registration mark Detecting means 16a Light source 16b Light receiving element 17_1 Driving roll 17_2, 17_3, 17_4 Follower roll 18 Paper tray 19 Registration roll 20Y, 20M, 20C, 20K Cleaner 21 Fixing device 22, 32, 42, 52, 62 Controller Over La 23_2 plastic sheet 53 steering roll

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DE02 DE07 DE09 EA02 EB04 EC03 EC06 EC07 EC09 ED02 ED06 ED16 EE03 EE04 EE05 EF01 2H030 AA01 AB02 AD04 AD05 AD17 BB02 BB23 BB44 BB56 2H032 AA05 BA01 BA01

Claims (9)

[Claims] 1. A belt control method for controlling the running of a belt running in a predetermined direction, wherein a belt to be controlled has at least a part of an image forming layer in which fine particles which move by electrophoresis to form an image are dispersed. Forming a fine particle image on the image forming layer by applying an electrostatic force corresponding to a predetermined image to the image forming layer of the running belt at a predetermined image forming unit; In the image measurement unit on the downstream side in the running direction of the belt than the part, the fine particle image formed on the image forming layer is measured, based on the measurement result of the fine particle image in the image forming unit,
A belt control method comprising controlling a running direction of the belt. 2. An endless belt having an image forming layer in which at least a part of particles which move by electrophoresis to form an image is dispersed in at least a part thereof and circulates in a predetermined direction. Electrostatic force applying means for forming a fine particle image on the image forming layer by applying an electrostatic force corresponding to a predetermined image to the image forming layer of the belt, a downstream side of the belt in the running direction of the belt from the image forming unit In the image measurement unit, an image measurement unit that measures the fine particle image formed on the image forming layer, based on the measurement result of the fine particle image in the image forming unit,
A belt control unit for controlling a running direction of the belt. 3. A plurality of photoconductors on which electrostatic latent images are formed on the surface while rotating, and a developing device for developing each electrostatic latent image formed on each of the plurality of photoconductors with a toner image of each color. And an endless belt circulating along the plurality of photoconductors, directly on the belt or on a predetermined image recording medium carried on the belt, in accordance with the movement of the belt. A belt for sequentially transferring a plurality of toner images formed on the plurality of photoconductors, and a color image formed by the toner images finally fixed on a predetermined image recording medium In the above, the belt has, at least in part, an image forming layer in which fine particles that move to form an image by electrophoresis are dispersed, and the image forming apparatus is configured to detect a position shift on the surface of the photoconductor. On the mark A mark latent image forming means for forming a corresponding mark latent image, wherein the photoreceptor applies an electrostatic force due to the mark latent image formed on the surface to the image forming layer of the belt to form fine particles on the image forming layer. Wherein the image forming apparatus further comprises a mark detecting means for detecting a mark formed on the image forming layer on the belt. 4. The image forming apparatus according to claim 3, wherein the belt has the image forming layer at both ends in a width direction crossing the running direction of the belt. 5. An image forming apparatus according to claim 3, further comprising control means for controlling timing of forming an electrostatic latent image on said photosensitive member based on a mark detection result by said mark detecting means. apparatus. 6. The image forming apparatus according to claim 3, further comprising control means for controlling a rotation speed of the photoconductor based on a mark detection result by the mark detection means. 7. An image forming apparatus according to claim 3, further comprising control means for controlling a moving speed of said belt based on a mark detection result by said mark detection means. 8. The image forming apparatus according to claim 3, further comprising control means for controlling meandering of the belt based on a mark detection result by the mark detection means. 9. A control unit for controlling a tilt of the photoconductor with respect to the belt or a tilt of formation of an electrostatic latent image formed on the photoconductor, based on a mark detection result by the mark detection unit. 4. The image forming apparatus according to claim 3, wherein: