JPH012082A - image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of the Invention The present invention generally relates to an image forming apparatus, and in particular, for example,
Image formation in which a visible image formed on an image carrier is transferred to a transfer material such as transfer paper or an intermediate transfer weight using an electrophotographic recording method such as an electrophotographic copying device. tF! Regarding 1.

As is well known, in LL stand-up image forming apparatuses, especially electrophotographic copying apparatuses using a Carlson electrophotographic process for forming one image, visible light is formed on a photoreceptor drum serving as an image carrier. When transferring an image, there is a device that directly transfers the image to a transfer material such as a transfer paper conveyed by an endless conveyor belt means, and a device that transfers the image directly to an intermediate transfer body such as a -1'l intermediate transfer drum. There is also a type that is later transferred to a transfer material such as transfer paper. In any of the above-mentioned types of electrophotographic copying apparatuses, the developer used to visualize the electrostatic latent image formed on the photoreceptor drum may cause transfer defects during the transfer, or The developer is scattered from a developing means such as a developing device storing the developer and adheres to the transfer material an surface of the conveyor belt means and the outer peripheral surface of the intermediate transfer drum, and due to this adhesion, the transfer material is placed on the conveyor belt. There is a problem that the surface and the outer peripheral surface of the intermediate transfer drum become dirty. In addition, when the above-mentioned transfer material is a transfer paper, in addition to the above-mentioned dirt, paper dust from the transfer paper adheres to the transfer material a22 surface of the conveyance belt means and the outer peripheral surface of the intermediate transfer drum, causing dirt. The problem is that it becomes even worse. Therefore, the transfer material 4 of the conveying belt means, such as the developer and paper dust of the transfer paper, is
! Various methods have been proposed for removing dirt on the transfer material mounting surface of the conveying belt means, the outer circumferential surface of the intermediate transfer drum, etc. by removing the dirt on the transfer material mounting surface of the conveying belt means, the outer circumferential surface of the intermediate transfer drum, etc. It was.

By the way, all of the methods proposed for the purpose of removing dirt adhering to the conveyor belt means, intermediate transfer drum, etc. mentioned above involve cleaning the fur brush or blade by A (sL) cleaning. The device is installed in a region of the electrophotographic copying device where dirt tends to occur, such as the transfer material at However, even with the cleaning device, the dirt adhering to the transfer material 4! placement surface of the conveying belt means and the outer peripheral surface of the intermediate transfer drum is immediately removed. Not all of the dirt is removed, and the degree of the dirt is not always constant and varies depending on how the electrophotographic copying device is used. In the case of the cleaning device that does not carry out this cleaning, it is not possible to keep the transfer material mounting surface of the above-mentioned conveyor belt means, the outer surface of the intermediate transfer drum, etc. always below a certain level of dirt (1°). When the electrophotographic copying apparatus is of a type that directly transfers a visible image formed on a photoreceptor drum to a transfer material conveyed by a conveyor belt, the side of the transfer material on which the visible image is not transferred is There is a problem in that dirt adhering to the surface (that is, the back surface) of the transfer material 41 of the f-stage of the conveyor belt is adhered to the transfer material 41, and on the other hand, the electrophotographic copying apparatus When the device is of a type in which the formed visible image is first transferred onto the outer peripheral surface of an intermediate transfer member such as an intermediate transfer drum, and then re-transferred to a transfer material, the image is transferred from the intermediate transfer drum during the re-transfer. Since dirt is also transferred to the transfer material along with the visible image, there is a problem that only one image of low quality can be formed.

Stop-1 Therefore, the present invention has been devised to improve the problems of the prior art as described above.

The purpose of this is to detect the state of dirt in parts of the device where paper dust from developer and transfer material tends to adhere, and to remove the dirt adhering to said parts according to the detected state of dirt. To provide an image forming apparatus capable of forming images with good, high-quality images without causing defects such as spot stains on the back or deterioration of image quality by variably setting the process. be.

8. For fortune-telling - The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention includes an image carrier and a moving member passing through a transfer area set for transferring a visible image of an electrostatic latent image formed on the image carrier from the image carrier. The image forming apparatus includes a dirt detection means for detecting dirt attached to the movable member, a cleaning means for cleaning the dirt attached to the movable member, and a detection signal output from the dirt detection means and a predetermined signal. The series of image forming operations is stopped in accordance with the comparison result with the set standard A1, and the movement 4! & Driving the member and the above 1+i
The image forming apparatus is characterized in that the drive of the sweeping means is controlled.

Support 1 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a color image forming apparatus according to an embodiment of the present invention.The outline of the color image forming apparatus according to an embodiment of the present invention is as follows. That is, in FIG. 1, a paper feed mechanism 13 is provided on one side of the image forming apparatus main body (hereinafter simply referred to as "r apparatus main body") 10, that is, on the right side in FIG. A transfer material outlet 14 is provided on the side opposite to the side where the paper feed mechanism 13 is provided, that is, the left side in FIG. 1, and a fixing device is provided facing the transfer material outlet 4. 7 are arranged. Below the section from the paper feed mechanism 13 to the fixing device 7 in the apparatus main body IO, there is a driven roller means, that is, an idler roller 12 close to the paper feed mechanism 13; Drive-side a-ra means, ie, drive a-ra 11, are provided in close proximity to each other on seven sides, and a moving member, ie, an endless transfer material conveying belt 8, is wound around these drive rollers 11 and idler rollers 12. There is. Below the drive roller 11,
An adjustment roller 76 is provided that comes into contact with the transfer material transport belt 8 from the inner peripheral side of the transfer material transport belt 8 and freely adjusts the tensile force of the transfer material transport belt 8 . Further, above the section from the idler roller 12 to the drive roller 11, there is an image forming section, that is, an image forming unit Pa adjacent to the transfer material conveying belt 8 and sequentially from the paper feeding mechanism 13 side.
, Pb, Pc, and Pd are arranged in parallel.

The above configuration will be described in more detail as follows. That is, the transfer material conveying belt 8 is driven by the drive roller 11 in the direction of the arrow in FIG. Each image forming unit Pa, Pb, P
c and Pd. The paper feeding mechanism 1
Reference numeral 3 denotes a paper feed force roller 51 which is detachable from the apparatus main body 10, and a rotatable paper feed roller 52 provided at a mounting portion of the apparatus main body 10 to which the paper feed cassette 51 is attached.
．． A paper feed guide 53 guides the transfer material 6 fed into the apparatus main body IO by the paper feed roller 52, and a feed roller receives the transfer material 6 guided by the paper feed guide 53 and bends it at a predetermined timing. 12 side, a sensor (not shown) that outputs a predetermined signal when detecting the leading end of the transfer material 6 moving within the paper feed guide 53, and the like. The paper feeding mechanism 13 is for placing the transfer material 6 onto the conveyor belt 8 from the idler roller 12 side. The fixing device 7 receives the transfer material 6 applied from the drive roller 11 side and connects the image forming units Pa, Pb, Pc,
The visible image transferred to the transfer material 6 is fixed by Pd. A paper discharge tray 117 is inserted into the transfer material discharge port 14 and is detachable from the apparatus main body 10 . Each of the image forming units Pa, Pb, P
The image forming units Pa, Pb, Pc, and Pd have substantially the same configuration.・Body drums la, lb, lc, ld, and each of these'
/(7) Loading devices 15a, 15b, 15c, and 15d sequentially provided around the drum in the drum rotation direction
, developing devices 3a, 3b, 3c, 3d, transfer discharge device 4a,
4b, 4c, 4d, cleaning means 5a.

5b, 5c, 5d, and the photosensitive drums 1a, 1b, l.
Imaging lenses 17a and 17a provided above c and ld, respectively.
7b, 17c, 17d and laser beam scanner 16a
, 18b, 16c, and lad. The developing device 3a is filled with magenta toner, the developing device 3b is filled with cyan toner, and development: Ii! Yellow toner is stored in the developing device 3C, and black toner is stored in the developing device 3d.

The laser beam scanners 16a, 16b, 16C11
6d is composed of a semiconductor laser, a polygon mirror, an fθ lens, etc., and upon receiving an input of an electric digital pixel signal, sends a laser beam modulated in accordance with the signal to the imaging lenses 17a, 17b, 17c, and 17d, respectively. via the charger 15a.

15b, 15c, 15d and developing units 3a, 3b, 3C13
d, the drum surface is exposed by scanning in the drum generatrix direction. The aforementioned laser beam scanner 1
The pixel signal corresponding to the magenta component image of the color image is sent to the laser beam scanner 16a, and the pixel signal corresponding to the cyan component image is sent to the laser beam scanner 16c.
A pixel signal corresponding to the yellow component image is input to the laser beam scanner 16d, and a pixel signal corresponding to the black component image is input to the laser beam scanner 16d. A suction charger (not shown) is provided between the image forming unit Pa and the paper feed mechanism 13, and the suction charger charges the transfer material 6 supplied from the paper feed mechanism 13. In order to ensure that the transfer material is attracted to the transfer material conveying belt 8, corona discharge is performed. on the other hand.

A static eliminator (not shown) is provided between the image forming unit (image forming unit) Pd and the fixing device 7, and approximately directly above the drive roller 11. An alternating current voltage is applied to separate the transfer material 6 that is attracted to the transfer material conveyance belt 8. On the upstream side in the conveyance direction of each of the above-mentioned image forming units (Pa, Pb, Pc, Pd,
Sensors 60a, 60b, 60c, and 60d are provided, and these sensors 60a, 60b, 60c, and 60d
is the transfer material 6 conveyed by the conveyor belt 8
Detects when the leading end of the image forming unit passes, and outputs a signal to an electronic circuit control means, ie, a control unit (not shown), to start the image forming process in each of the image forming units) Pa, Pb, Pc, and Pd. is configured to do so.

Now, when the transfer material 6 in the form of a cut sheet moves within the paper feed guide 53 of the paper feed mechanism 13, its leading edge is detected by the sensor.

Each image forming unit Pa, Pb-, P uses the signal outputted from the sensor by this detection as a start signal.
The photosensitive drums la, 1b, lc, and ld of c and Pd start rotating. The drive roller 11 is also driven at the same time,
The transfer material conveying belt B starts driving in the direction of the arrow in FIG. When the transfer material 6 is guided by the paper feed guide 53 and placed on the transfer material conveyance belt 8, it is reliably attracted to the transfer material conveyance belt 8 by corona discharge from the adsorption charger. be done. As the transfer material conveying belt 8 moves in the direction of the arrow in FIG. Image formation on drums la, lb, 1c, and ld is sequentially started.

That is, the first image forming unit Paf) photosensitive drum 1a
The magenta image is assigned to the second image forming unit (Pb), the yellow image is assigned to the third image forming unit (Pc), and the black image is assigned to the fourth image forming unit (Pd). It is formed by Each of the image forming units Pa
, Pb, Pc.

The principle of image formation in Pd is already well known as the Carlson process, so its explanation will be omitted. As the transfer material conveying belt 8 moves, the transfer material 6 is moved toward the fixing device 7 to the first to fourth image forming units Pa-Pd.
The transfer dischargers 4a, 4b, 4C14 of each unit are conveyed sequentially passing through the lower part of the photoreceptor drums la to ld.
d, each color is sequentially transferred onto the surface of the transfer material 6 in an overlapping manner to synthesize a color image. When the transfer material 6 passes through the fourth image forming unit Pd, the charge is removed from the transfer material 6 by the static eliminator to which an alternating current voltage is applied, and the transfer material 6 is separated from the transfer material conveyance belt 8 . The transfer material 6 separated from the transfer material conveyance belt 8 enters a fixing device 7, where the image is fixed, and then is discharged from the transfer material discharge port 14 to a paper discharge tray 117. , one print cycle is completed.

Further, according to an embodiment of the present invention, a dirt detection stage 106 for detecting dirt attached to the transfer material conveyance belt 8 marked # is provided, and a cleaning device for cleaning the dirt attached to the transfer material conveyance belt 8 is provided. Means 107 is provided, and performs a series of image forming operations, that is, the outer peripheral surface of each of the photoreceptor drums 1a to 1d, according to the comparison result between the detection signal output from the dirt detection means 106 and a preset reference value. Formation of an electrostatic latent image on each developing unit 3a to 3d of the electrostatic latent image
The transfer material 6 of each visible image is visualized by
The circulation movement of the transfer material conveying belt 8 and the driving of the cleaning means 107 are controlled by stopping each operation such as transfer to the transfer material.

To explain the above-mentioned configuration in detail, the dirt detection means 1
06 is the transfer material conveying belt 8 of the adjusting roller 76.
In this embodiment, the stain detection means 10 is disposed close to the transfer material conveying belt 8 on the downstream side in the moving direction of the transfer material conveying belt 8.
Reference numeral 6 denotes a light source 106a that irradiates light toward the transfer material transport belt 8 from the outer peripheral surface side of the transfer material transport belt 8, which is the transfer material mounting surface of the transfer material transport belt 8; The light receiving element 106b is disposed on the inner peripheral surface side and receives light incident from the light source 106a via the transfer material conveying belt 8.

The light receiving element 1osb is configured to output an electric signal corresponding to the amount of light received to the control unit (not shown) described above. The cleaning means 107 is disposed near the dirt detection means 106 on the downstream side of the transfer material conveyance belt 8 in the moving direction of the transfer material conveyance belt 8 and close to the outer peripheral surface of the transfer material conveyance belt 8 . The cleaning means 107 is
A frame body 107b installed close to the outer peripheral surface of the transfer material conveyance belt 8 has an axis set in a direction substantially perpendicular to the moving direction of the transfer material conveyance belt 8, and is connected to the frame body 107b. The fur brush 107a is configured to be rotatably brought into contact with the outer peripheral surface of the transfer material conveying belt 8 by a motor (not shown). The driving of the fur brush 107a is controlled by a drive command signal output from the control unit (not shown) described above to the motor (not shown).

Next, the control operation of the above-described configuration will be explained mainly with reference to the flowchart shown in FIG. 2.

When each image formation process progresses and it is recognized by some means that the step of transferring the visible image to the last preset transfer material 6 has been completed (Stella 7'201)
, the control unit reads the dirt detection signal output from the dirt detection means 106 and starts an operation of checking the dirt state of the outer peripheral surface, which is the transfer material storage surface of the transfer material conveying belt 8 (step 203); 2
After starting the operation shown in 03, the cleaning means 107
A main timer provided in the control unit is set to set the maximum cleaning time of the transfer material mounting surface of the transfer material conveyance belt 8 (step 205), and the transfer material conveyance belt 8 A timer provided in the control unit is set to set a time slightly longer than the time required for one revolution of the controller (step 207), a main timer is set in step 205, and the main timer is set in step 20.
When the timer is set in step 7, it is determined in step 203 whether or not the read dirt detection signal is lower than a reference value preset in the memory in the control unit. When it is recognized that the value is lower than the reference value, that is, when it is recognized that there is no need to drive the cleaning means 107 (step 20
9), proceed to step 217. When it is determined that the count of the tires exceeds the time set in step 207, the dirt detection operation of the transfer material conveying belt 8 is terminated, while the count of the timer is determined to exceed the time set in step 207. If it is determined that the set time has not been exceeded, the process moves to step 209 and continues the dirt detection operation. In step 209, when it is recognized that the value of the dirt detection signal is higher than the reference value, that is, when it is recognized that it is necessary to drive the cleaning means 107, a drive command signal is output to the aforementioned motor (not shown). By rotating the fur brush 107a for a certain period of time,
Clean the transfer material mounting surface of the transfer material conveying belt 8 (step 211), and if it is determined that the main type count does not exceed the time set in step 205 (step 213), proceed to step 207. Then, the timer is set again and the dirt detection operation is continued. On the other hand, if it is determined in step 213 that the count content of the main timer exceeds the time set in step 205, a drive command signal is sent to an alarm means (not shown) installed in the image forming apparatus. output to warn that the transfer material mounting surface of the transfer material conveying belt 8 is so dirty that it cannot be cleaned within the maximum cleaning time that can be set by the main timer (
Step 215), the predetermined control operation is ended. In addition,
Once the above-mentioned alarm means (not shown) issues an alarm, the cleaning means 107 is no longer able to remove the dirt adhering to the surface of the transfer material a2i of the transfer material conveying belt 8. Then, the operator must remove the dirt using a comb or replace the transfer material conveying belt 8 with a new one.

As explained above, according to the image forming apparatus according to the embodiment of the present invention, when the state of dirt attached to the transfer material mounting surface of the transfer material conveyance belt 8 is not so severe, the transfer material The belt 8 places the transfer material 6 on the first
The stains can be removed by simply setting a very short period of time during which the transfer material conveyance belt 8 is rotated idly, without being conveyed in the Pa-Pa direction (each image forming unit shown in the figure). If there is no dirt at all, it is sufficient to move the transfer material conveying belt 8 one round to detect dirt. Furthermore, if dirt is attached to the transfer material mounting surface of the transfer material transport belt 8, the number of times the transfer material transport belt 8 is rotated idly increases depending on the state of the dirt. Therefore, problems such as unnecessary intermediate rotation of the transfer material conveying belt 8 can be prevented. Furthermore, if dirt that cannot be cleaned by automatic cleaning by the cleaning means 107 adheres to the transfer material mounting surface of the transfer material conveying belt 8, the I-sweeping operation may be continued for a long time. The alarm means (
(not shown), so do not operate the device with the dirt left as it is and continue to operate the device (image forming unit).
It has become possible to eliminate problems such as those that adversely affect transfer in -Pd.

FIG. 3 is a flowchart showing the control operation when the home position is set for the transfer material conveying belt 8 of the image forming apparatus shown in FIG. 1, and FIG. One difference from the illustrated flowchart is that the flowchart is different from the transfer material conveying belt 8.
By setting the home position to
The main point is that the setting operation of the main timer and timer shown in the figure and the operation of checking the count contents of each of these timers are omitted. When the operations shown in steps 301 and 303 are completed, the control unit (not shown) uses a home position sensor (not shown) for detecting the home position of the transfer material conveying belt 8.
When it is recognized that the dirt detection signal tB outputted from the dirt detection means 106 is lower than the preset 2Si* value (step 307), the Check whether a new detection signal is output from the home position sensor (step 317), step 317
When a new detection signal is output from the home position sensor, it is recognized that the belt 8 has moved one revolution and the control operation is stopped, and when the new detection signal is not output, step -Moves to 307. In step 307, when it is recognized that the value of the dirt detection signal read in step 303 is higher than the reference value and cleaning by the cleaning means 107 is necessary, a drive command signal is sent to the aforementioned motor (not shown). is output to rotate the fur brush 107a for a certain period of time to clean the transfer material mounting surface of the transfer material conveying belt 8 (step 309). When the operation illustrated in step 309 is completed, the Checks how many times a new detection signal has been output from the position sensor, and when it is recognized that the number of detection signals output from the home position sensor has reached a preset number (N) (step 311). , step 31 to output a drive command signal to drive the alarm means.
9) Stop the control operation. In step 311,
When it is recognized that the number of detection signals output from the home position sensor has not reached the N times, a certain period of time has elapsed from the time when it was recognized that a new detection signal was output from the home position sensor. (Step 313), the driving of the fur brush 107a is stopped (Step 315), and the process moves to Step 307.

FIG. 4 shows a color image forming apparatus according to another embodiment of the present invention. A color image forming apparatus according to another embodiment of the present invention is shown in FIG. Instead of placing the transfer material 6 on a transfer material conveying belt 8 like the device shown in , and transferring the visible images formed on each of the photoreceptor drums la to ld to the transfer material 6. The visible images formed on each of the photosensitive drums 1a to 1d are once transferred to the intermediate transfer belt 108, which is a moving member, that is, an intermediate transfer member, and then the visible images transferred to the intermediate transfer belt 10B are transferred. intermediate transfer bell) 108
It is configured to re-transfer from the image to the transfer material 6. That is, in FIG. 3, when the intermediate transfer belt 108 is driven counterclockwise in FIG. The transferred visible image is transferred onto the intermediate transfer belt 108 in the order of magenta, yellow, and black.

A transfer roller 130 and a backup roller 1 apply appropriate pressure or heat to the intermediate transfer belt 10g and the transfer material 6.
31, the image is successfully transferred from the intermediate transfer belt 108 to the transfer material 6 and fixed. , cleaning means 107 and the first cleaning means 107.
The intermediate transfer belt 108 and the cleaning means 10 are arranged in the manner shown in the figure, and are processed by the process shown in FIG. 2 or the process shown in FIG. 3.
By controlling the driving of the intermediate transfer belt 108, it is possible to keep the outer circumferential surface of the intermediate transfer belt 108, which is the visible image bearing surface, free of dirt at all times. In the embodiment shown in FIG. 1 and this embodiment, for convenience of explanation, the dirt detection means 106 is composed of a light source 106a and a light receiving element 106b, and the cleaning means 107 is composed of a light source 106a and a light receiving element 106b. decided to use one equipped with a fur brush 107a, but the dirt detector ryt106 was
The sensor is not limited to a so-called transmission type consisting of a light source 106a and a light receiving element 106b; for example, a single reflection type optical sensor means or a CCD may be adopted.
On the other hand, regarding the cleaning means 107, the fur brush 1
Under the control of the control unit, a blade for scraping off the adhered dirt is used instead of the belts 8 and 1.
It is also possible to use a structure that allows it to be brought into contact with or separated from 08 or the like.

As explained above, according to the present invention, it is possible to detect the state of dirt in areas where developer or transfer material paper dust, etc. in the device is likely to adhere, and to detect the state of the detected dirt. By variably setting the process for removing dirt attached to the area depending on the island, it is possible to form images with good, high-quality images without causing problems such as so-called back dirt or deterioration of image quality. An image forming apparatus capable of performing the following steps can be provided.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the overall configuration of a color image forming apparatus according to an embodiment of the present invention. FIGS. 2 and 3 are flowcharts showing control operations in the color image forming apparatus according to the present invention, respectively. FIG. 4 is a longitudinal sectional view showing the overall configuration of a color image forming apparatus according to another embodiment of the present invention. 1a, lb, lc, ld: Photosensitive drum 8: Transfer material conveying belt 106: Dirt detection means 107: Cleaning means 108: Intermediate transfer belt

Claims (1)

[Scope of Claims] 1) An image carrier and a moving member that passes through a transfer area set for transferring a visible image of an electrostatic latent image formed on the image carrier from the image carrier. The image forming apparatus includes a dirt detection means for detecting dirt attached to the movable member, a cleaning means for cleaning the dirt attached to the movable member, and a detection signal output from the dirt detection means and a predetermined signal. An image forming apparatus characterized in that a series of image forming operations is stopped according to a comparison result with a set reference value, and driving of the moving member and driving of the cleaning means are controlled. 2) The drive control of the moving member and the drive control of the cleaning means are performed by stopping the series of image forming operations, such that the detection signal output from the dirt detection means reaches a preset value. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to perform the image forming process until the end of the image forming process. 3) The driving control of the moving member performed by stopping the series of image forming operations is performed until a preset time elapses. The image forming apparatus described above. 4) A predetermined alarm is issued when the detection signal output from the dirt detection means has not reached a preset value even after a preset time has elapsed. An image forming apparatus according to claim 1. 5) The movable member is a transfer material conveying means for conveying a transfer material to which a visible image formed on the image carrier is transferred. The image forming apparatus according to any one of the items. 6) The movable member is a transfer medium that receives the transfer of the visible image formed on the image carrier, according to any one of claims 1 to 4. Image forming device.