JP3192276B2 - Cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a cleaning device used in an image forming apparatus utilizing an electrophotographic process.

[0002]

2. Description of the Related Art An image forming apparatus using an electrophotographic process, such as a copying machine, a facsimile, and a printer, forms an image by transferring and fixing a toner image formed on a photoreceptor onto recording paper. Since toner and the like remain on the surface of the photoreceptor after the transfer, a cleaning step for removing the toner and the like is required in order to use the next image. For this reason, a cleaning device is arranged downstream of the transfer position. This cleaning device generally has a configuration in which a blade or a brush is brought into contact with the surface of a photoreceptor to remove residual toner, and the removed toner is collected in a collection tank or the like. In the case where the toner image once transferred from the photoreceptor onto the intermediate transfer member is transferred onto recording paper, cleaning is performed by bringing a blade or the like into contact with the intermediate transfer member.

In a color copying machine in which a plurality of color toner images are superimposed on a photoreceptor or an intermediate transfer member and then transferred onto recording paper, toner images of all colors are formed on a photoreceptor or the like. It is necessary to continuously rotate the photoreceptor, etc., but if the cleaning is performed during the continuous rotation, the formed toner image is removed. It is kept in a state of being retracted from the surface. Then, only after one transfer is completed, the blade or the like of the cleaning device contacts the surface of the photoconductor or the like to remove the residual toner. As described above, in the color copying machine, since the blade separates from the photoreceptor or the like in each image forming process, the amount of toner scraped by the blade scatters in the machine. Also, in a black-and-white copying machine, as the number of blade releases increases, the amount of toner scattered increases in proportion thereto, thereby contaminating the inside of the machine and increasing the number of maintenance operations. Further, when the stain becomes worse, the transfer charger and the like are stained, which causes image deterioration.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and even when the number of times a cleaning blade contacts and separates from a photoreceptor or the like is large, contamination inside the apparatus due to scattering of toner is minimized to increase maintenance work. It is an object of the present invention to provide a cleaning device that prevents deterioration of image quality.

[0005]

To achieve the above object, the present invention provides a removing means for removing toner from an image carrier, a toner transport screw for transporting the removed toner, a housing for accommodating these components, A cleaning device provided with a mechanism for integrally contacting and separating each component including the housing from the surface of the image carrier, wherein the toner conveying screw is used when each component including the housing is separated from the image carrier; , A removing unit for removing the toner from the image carrier, a toner transport screw for transporting the removed toner, a housing for housing these components, In a cleaning apparatus provided with a mechanism for integrally bringing each component including a body into and out of contact with the surface of the image carrier, a fan for forming a negative pressure is provided in an opening formed in the housing, and The unit controls the fan to operate when each component including the housing is separated from the image carrier, and the opening is formed in a housing wall surface at a position immediately above the toner conveying screw. A filter is disposed inside the fan provided in the opening, and the toner adhered to the filter is dropped onto the toner conveying screw by vibration when the cleaning device advances and retreats from the image carrier. It is characterized by the following.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 is an explanatory view of a configuration of a color copying apparatus to which the cleaning device of the present invention is applied, and FIG. Color image reading device (hereinafter, referred to as color scanner) 1
Forms an image of the reflected light of the light emitted from the illumination lamp 4 onto the image surface of the document 3 on the contact glass CG via a mirror group 5 and a lens 6 on a color sensor 7 to convert the color image information of the document. For example, each color separation light of Blue, Green, Red is read and converted into an electric image signal. And B obtained by this color scanner 1
Based on the G and R color separation image signal intensity levels, an image processing unit (not shown) performs a color conversion process, and
(Hereinafter, referred to as Bk), Cyan (hereinafter, referred to as C),
Magenta (hereinafter, referred to as M) and Yellow (hereinafter, referred to as Y) color image data are obtained.

Next, Bk, C, M, and Y are visualized by a color image recording device (hereinafter, referred to as a color printer) 2 and are superimposed to form a four-color full-color image.

Next, an outline of the color printer 2 will be described. The writing optical unit 8 converts color image data from the color scanner 1 into an optical signal, performs optical writing corresponding to a document image, and forms an electrostatic latent image on a photosensitive drum (image carrier) 9. The photoreceptor drum 9 rotates counterclockwise as indicated by an arrow, and around the photoreceptor cleaning unit (including a pre-cleaning static eliminator) 10, a static elimination lamp 11, a charger 12, a potential sensor 13, a Bk developing device 14, a C developing unit 15, an M developing unit 16, a Y developing unit 17, a development density pattern detector 18, an intermediate transfer belt 19, and the like. Each developing device includes a developing sleeve (14-1, 15-1, 16-1, 17-1) that rotates so that the developer faces the photoconductor 9 in order to develop an electrostatic latent image; It is composed of a developing paddle that rotates for pumping up and stirring, a sensor for detecting the toner concentration of the developer, and the like. The order of the developing operation (color image forming order) is Bk, C,
Examples of M and Y will be described below. However, the image forming order is not limited to this.

When the copying operation is started, reading of Bk image data is started at a predetermined timing by the color scanner 1, and light writing by a laser beam and formation of a latent image are started based on the image data. (Hereinafter, the electrostatic latent image based on the Bk image data is referred to as a Bk latent image. The same applies to C, M, and Y.)
Before the leading end of the latent image reaches the developing position of the k developing unit 14, the rotation of the developing sleeve 14-1 is started to develop the Bk latent image with Bk toner. Thereafter, the developing operation of the Bk latent image area is continued, but when the rear end of the Bk latent image passes the Bk developing position, the developing operation is stopped. This is completed at least before the leading end of the C latent image based on the next C image data arrives.

The Bk toner image formed on the photosensitive member 9 is transferred to the surface of an intermediate transfer belt 19 which is driven at a constant speed with the photosensitive member (hereinafter, a toner image is transferred from the photosensitive member to the intermediate transfer belt). Is referred to as a belt transfer). The belt transfer is performed by applying a predetermined bias voltage to the transfer bias roller 20 in a state where the photoconductor 9 and the intermediate transfer belt 19 are in contact with each other. The Bk, C, M, and Y toner images sequentially formed on the photoreceptor 9 are sequentially aligned on the same surface of the intermediate transfer belt 19 to form a four-color superimposed belt transfer image. Perform transcription. The configuration and operation of the intermediate transfer belt unit will be described later.

On the photoreceptor 9 side, after the Bk process, C
In the process, reading of C image data by the color scanner 1 starts at a predetermined timing, and a C latent image is formed by writing a laser beam based on the image data. C developing device 1
Reference numeral 5 denotes the developing sleeve 1 after the trailing end of the preceding Bk latent image has passed the developing position and before the leading end of the C latent image has arrived.
5-1 is started to develop the C latent image with the C toner. Thereafter, the development of the C latent image area is continued, but when the rear end of the latent image has passed, the development is disabled as in the case of the Bk developing device. This is also completed before the leading end of the next M latent image arrives. In the processes of M and Y, the respective operations of reading image data, forming a latent image, and developing are performed in the above-described B mode.
Since this is the same as the step of k · C, the description is omitted.

Next, the intermediate transfer belt unit will be described. The intermediate transfer belt (image carrier) 19 is stretched around a drive roller 21, a belt transfer bias roller 20, and a group of driven rollers, and is driven and controlled by a drive motor (not shown) as described later. The belt cleaning unit 22 includes a brush roller (removal means) 22-1, a rubber blade (removal means) 22-2, a mechanism 22-3 for contacting and separating from the belt, and the like. After the transfer, the second, third, and fourth colors are separated from the belt surface by the contact / separation mechanism 22-3 during the belt transfer. The paper transfer unit 23 includes a paper transfer bias roller 23-1, a roller cleaning blade 23-2,
And a mechanism 23-3 for contacting and separating from the belt. The bias roller 23-1 is usually provided with a belt 19.
However, when the four-color superimposed images formed on the surface of the intermediate transfer belt 19 are collectively transferred to recording paper, the four-color superimposed images are pressed by the contact / separation mechanism 23-3 in a timely manner.
A predetermined bias voltage is applied to 3-1 to perform transfer to paper.

The recording paper 24 is fed by a paper feed roller 25 and a registration roller 26 at the timing when the leading end of the four-color superimposed image on the intermediate transfer belt surface reaches the paper transfer position. The recording paper 24 on which the four-color superimposed toner image is collectively transferred from the intermediate transfer belt surface is transferred to a paper transport unit 27.
Then, the toner image is fused and fixed by the fixing roller 28-1 and the pressure roller 28-2 controlled to a predetermined temperature, and is carried out to the copy tray 29 to obtain a full-color copy. The surface of the photoreceptor 9 after the belt transfer is cleaned by the photoreceptor cleaning unit 10 and is uniformly discharged by the discharge lamp 11. Also,
Intermediate transfer belt 1 after transfer of toner image to recording paper 24
Reference numeral 9 designates the cleaning unit 22 again as a contact / separation mechanism 22-3.
Press to clean the surface. Although the copy mode for obtaining four full colors has been described above, in the other multi-color modes, the same operation as described above is performed for the designated color and the number of times. In the case of a single-color copy, only the developing device of that color is set in the developing operation state until the predetermined number of copies is completed, and the intermediate transfer belt 19 is driven at a constant speed in the forward direction while being in contact with the surface of the photoconductor 9. The belt cleaner 22 also performs the copying operation while keeping the belt 19 in contact with the belt 19.

FIGS. 3 and 4 are explanatory views of a specific configuration of the cleaning device (cleaning unit) 22 of the present invention. FIG. 3 shows a state during cleaning (pressurized state) and FIG. 4 shows a state during evacuation. . Housing 10 of cleaning device 22
0, the brush roller 22-1 and the rubber blade 22
In addition, a toner conveying screw 102 is supported in a recess 101 located at the bottom of the housing 100 so as to be rotatable about its axis in a direction perpendicular to the paper surface. The screw 102 is rotated by driving a driving motor according to a control signal from the control unit, and conveys the toner scraped and dropped by the brush roller and the blade in a direction perpendicular to the paper surface and collects the toner in a collection unit (not shown). Things. An opening 103 is formed in a wall surface extending substantially perpendicularly from the recess 101 and the opening 1 is formed.
03, a fan 104 outside, and a filter 105 inside.
Are arranged respectively.

During the cleaning shown in FIG. 3, since the cleaning brush 22-1 is rotating, the toner scraped from the surface of the belt 19 scatters and flies in the housing 100.
The airflow is turbulent and the unit internal pressure is high. When the pressurization is released as shown in FIG. 4 in this state, the toner blows out from the gap between the belt 19 and the casing to the outside, thereby contaminating the inside of the apparatus. As a countermeasure, if the pressure is released after waiting for a while after the cleaning is completed, the toner scattering amount can be reduced to some extent, but a considerable amount is still ejected into the apparatus. Further, if the release of the pressure is delayed in this manner, the processing speed of the color copy is greatly reduced. Therefore, if priority is given to a request for quicker timing of the release of the pressure, it is necessary to tolerate toner scattering. As another measure, it is conceivable to form an air vent in the housing to reduce the internal pressure in the housing 100. However, since the air flow is turbulent in the housing, a considerable amount of toner is released when the pressurization is released. It still leaks out.

Therefore, in the first embodiment of the present invention, the inside of the housing 100 is always kept at a negative pressure (compared with the internal pressure outside the housing) by rotating the screw 102, which is a means for conveying the collected toner, at a high speed. The screw driving motor is controlled so that the screw is kept rotating and the negative pressure is maintained even when the pressure is released, so that the toner does not blow out of the housing when the pressure is released. With this configuration, it is possible to reduce the amount of toner scattered even when the frequency of pressure release is increased.

Next, in a second embodiment of the present invention, the fan 1
04 forcibly reduces the internal pressure of the housing 100 to a negative pressure to prevent the toner from spouting when the pressure is released. In other words, most of the toner collected by the brush and the blade is discharged to the outside of the housing by the transport screw 102, but only the toner floating in the housing is quickly sucked by the fan 104 toward the outside of the housing, and is discharged to the outside of the housing. Filter 1 before discharging
05. The purpose of the fan 104 is not to collect the toner, but to generate a negative pressure to adsorb and remove the floating toner.

If the toner adhering to the filter 105 is not removed and collected, the toner accumulates at a rapid pace and causes clogging, thereby blocking the opening 103. However, it is troublesome to replace the filter at regular intervals. Therefore, in the present invention, the toner deposited on the filter is easily dropped onto the screw 102 by disposing the filter 105 at a position immediately above the transport screw 102. In other words, the toner is dropped onto the screw by the vibration of the contacting / separating operation when the cleaning device is pressurized and released, and is conveyed to the outside of the housing as it is, so that the filter can be used continuously without causing clogging. You can continue. Further, by configuring the edge of the opening 103 including the filter to vibrate by the rotational force of the screw when the screw rotates, or by configuring the filter to vibrate by the rotational force of the fan, toner adhered to the filter can be removed. You may make it fall. Further, if the filter is configured to be detachable from the outside of the housing, it is easy for the user to replace and clean the filter, and the user vibrates a part of the filter protruding to the outside of the housing to drop the attached toner. You may do so.

Although the specific structure of the contact / separation mechanism 22-3 is not shown in FIGS. 3 and 4, the housing 100 is urged and released using a solenoid, a motor, a spring, or the like, as usual. What is necessary is just to comprise so that a force may be released. In the above embodiment, an example using a transfer belt has been described. However, the present invention can also be applied to a cleaning device used for a type in which transfer is directly performed from a photoconductor.

[0020]

As described above, the present invention relates to a cleaning device for removing residual toner and the like on the surface by making contact with a photoreceptor and a transfer belt so as to be able to move forward and backward. In order to prevent the toner from scattering in the machine when the number of times of release is large, the conveying screw in the cleaning device is rotated at high speed to make the inside of the housing a negative pressure, or the fan generates negative pressure, so it is excellent. An effect of preventing toner scattering can be exhibited.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of an image forming apparatus to which the present invention is applied.

FIG. 2 is an enlarged view of an image forming unit in FIG. 1;

FIG. 3 is an enlarged view showing the entire configuration of the cleaning device, showing a state at the time of pressurization.

FIG. 4 is an enlarged view showing a state when pressure is released.

[Explanation of symbols]

22 belt cleaning unit (cleaning device), 22-1 brush roller (removal means), 22-2
Rubber blade (removal means), 22-3 contact / separation mechanism, 1
00 housing, 101 recess, 102 toner conveying screw, 103 opening, 104 fan, 105 filter,

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 21/10-21/12 G03G 15/16-15/16 103

Claims (3)

(57) [Claims] 1. A removing means for removing toner from an image carrier, a toner transport screw for transporting the removed toner, a housing for accommodating these components, and each component including the housing are integrally formed. A cleaning unit provided with a mechanism for coming and going from the surface of the image carrier, comprising a control unit that controls the toner transport screw to operate when each component including the housing is separated from the image carrier. A cleaning device. 2. The cleaning device according to claim 1, wherein
A negative pressure generating fan is provided in the opening formed in the housing , and the control unit controls the fan to operate when each component including the housing is separated from the image carrier. A cleaning device, comprising: 3. The cleaning device according to claim 2, wherein
Te retreat, together with the upper Symbol openings are formed in the housing wall at the position directly above the toner conveying screw, a filter disposed on the inside of the fan provided to the opening, the cleaning device from the image carrier features and to torque cleaning apparatus by being configured such that the toner adhering to the filter falls onto the toner conveying screw by the vibration of when.