JPH04194878A - Cleaning device - Google Patents

Abstract

PURPOSE:To perform picture forming work with high cleaning performance further with an image carrier in high reliability over a long period by bringing a contact member into contact with the image carrier by pressing force at a predetermined pressure or less, at the time of no work, while by pressing force at the predetermined pressure at the time of work for removing a residual toner. CONSTITUTION:When a residual toner is removed by a cleaning device 12, a controller outputs a signal to a solenoid 23 just before a point end of a picture forming region reaches the cleaning device 12, so that the solenoid 23 brings a toner blade 19 into contact by pressing force of about 45gf/cm relating to a sensitized drum 7. Consequently, the residual toner is previously scraped off by a cleaning brush 20 and then by sufficient pressing force by the blade 19, and when removing work of the toner is finished, the signal output to the solenoid 23 is interrupted, so that the solenoid 23 is reset to the original condition. Consequently, the collected toner and the floated toner are prevented from scattering.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device, and more particularly, to a cleaning device having a contact member that contacts an image carrier with different pressing forces during residual toner removal work and when not working. Regarding.

[Conventional technology]

Generally, an image forming apparatus such as a copying machine is provided with a known image carrier such as a photosensitive drum, a charging device, a developing device, a transfer device, a static eliminator, and the like.

In addition to the above-mentioned devices, in order to repeatedly form images on transfer paper using a photosensitive drum, a copying machine is equipped with a cleaning device that repeatedly removes residual toner adhering to the drum surface. ,
For example, there is a brush cleaning method in which a rotatable brush is brought into contact with the photoreceptor drum to scrape off residual toner from the photoreceptor drum, and a magnetic brush of a magnetic carrier is formed on a magnetic roller and the toner is rubbed and collected by the magnetic brush. The magnetic brush cleaning method uses a fur brush L on a magnetic roller to rub residual toner (in this case, the toner is magnetic toner) and collects it using magnetic force, and the toner blade There is a blade cleaning method in which residual toner is scraped off by bringing the tip of the blade into contact with a photoreceptor drum.

Further, as a cleaning device that combines the above-mentioned methods, for example, there is a device that combines a brush cleaning and a toner blade, and this method is becoming the mainstream of cleaning devices these days. This cleaning device includes a toner blade whose tip comes into contact with the photoreceptor drum, and a cleaning brush that is disposed on the front side in the rotational direction of the photoreceptor drum with respect to the toner blade. Then, residual toner adhering to the photosensitive drum is scraped off in advance with a cleaning brush, and then the toner is completely scraped off with a toner blade and collected into the cleaning device. However, in this type of cleaning device, the residual toner is scraped off by a brush cleaning and a toner blade, which improves the cleaning performance, but the tip of the toner blade has a strong pressing force on the surface of the photoreceptor drum. Because of this, the drum surface wears out prematurely and the electrostatic properties deteriorate. In other words, there is a very close relationship between the pressure applied to the toner blade and the amount of wear on the surface of the photoreceptor drum. This increases capacitance and the like, making it easier for electrostatic potential to fluctuate. This causes a problem that image quality is degraded and the life of the photoreceptor drum is shortened as a result.

As a method for solving such problems, for example, the method described in Japanese Patent Publication No. 1-46872 is known. This device brings the toner blade into contact with the photoconductor drum with a predetermined pressure during cleaning operations, and separates the toner blade from the photoconductor drum during non-operation to prevent the blade from constantly contacting the photoconductor drum. By doing so, it is possible to prevent the photoreceptor drum from being worn out prematurely, and to significantly improve its lifespan.

[Problem to be solved by the invention]

However, in such conventional cleaning devices, the toner blade is separated from the photoreceptor drum when not working, so cleaning is performed when the toner blade is separated from the photoreceptor drum after toner removal work is completed. The toner collected in the device scatters toward the photoreceptor drum and adheres to the surface of the static eliminator that removes the charges accumulated on the photoreceptor drum surface, reducing the amount of static electricity removal light and damaging the photoreceptor drum surface. There have been problems such as adhesion to the charging device, which causes charging unevenness. In particular, if the toner brush is disposed on the front side of the photoreceptor drum in the rotational direction with respect to the toner blade, the toner scraped off by the toner brush may be inside the cleaning device and between the photoreceptor drum and the cleaning device. Since the toner is floating, when the toner blade is separated, the toner is further scattered toward the photoreceptor drum, which exacerbates the above problem.

[Purpose of the invention]

Therefore, the present invention provides a cleaning method that prevents wear of the image bearing member and prevents toner from scattering, thereby providing high cleaning performance and allowing the image bearing member to perform image forming operations with high reliability over a long period of time. The purpose is to provide equipment.

[Means to solve the problem]

In order to achieve the above object, a cleaning device according to the present invention includes a contact member that contacts an image carrier, and after a toner image formed on the image carrier is transferred to a transfer paper, the contact member In a cleaning device that removes toner remaining on an image bearing member, the contact member is brought into contact with the image bearing member with a predetermined pressing force during a residual toner removal operation, and the contact member is brought into contact with the image bearing member with a predetermined pressing force or less during non-operation. It is characterized by comprising a control means for bringing the image carrier into contact with pressure.

Hereinafter, the present invention will be explained based on examples.

1 to 7 are diagrams showing an embodiment of the cleaning device according to the present invention.

First, the configuration will be explained. FIG. 1 is a diagram showing an image forming apparatus. In the figure, reference numeral 1 denotes an image forming apparatus, and this apparatus 1 includes a known image reading section 6 comprising a fluorescent lamp 2, a lens 3, an image reading plate 4, a polygon motor 5, etc.
, a photoreceptor drum 7 as an image carrier, a charge removal device 8 having a charger and a charge removal lamp, and a developing device 9.
, a transfer charger 10 as a transfer device, a separation charger 11, a cleaning device 12, and a fixing device 13.
and a main motor M are provided. The photosensitive drum 7 has a negatively charged photosensitive layer, is formed in a cylindrical shape, and extends in the direction of the plane of the drawing. The charging potential of the charger is set to 1800 mm, and the surface of the photosensitive drum 7 is uniformly charged.

The image reading section 6 reads an image of a document (not shown) placed on the contact glass 14 with a laser beam, and scans and exposes the image with the laser beam in a direction perpendicular to the direction of rotation of the photosensitive drum 70 (indicated by an arrow). Yes, photosensitive drum 7
An electrostatic latent image corresponding to the original is formed on the surface, and the potential of this latent image is set to 1100V. The developing device 9 is provided with a two-component developer containing negatively charged toner therein, and has a developing roller 9a located close to the photosensitive drum 7. The developing roller 9a is set at a bias potential of 600 V, and supplies developer to the photosensitive drum 7 to visualize the electrostatic latent image. The electrostatic latent image on the surface of the photoreceptor drum 7 is visualized in this way because the latent image potential VL
is set to -100V, and the bias potential v6
is set to -600V, and the potential difference between these (VL
This is because Vl) becomes 500■.

The transfer charger 10 is configured to transfer the visible toner image formed on the surface of the photoreceptor drum 7 to transfer paper (not shown) fed from either one of the paper feed cassettes 15 and 16, and the separation charger 11 is configured to transfer the visible toner image formed on the surface of the photoreceptor drum 7 to transfer paper (not shown) fed from either one of the paper feed cassettes 15 and 16. The subsequent transfer paper is separated from the photosensitive drum 7. The fixing device 13 includes a pair of pressure rollers 13a and 13b.
When the transfer paper after the transfer is conveyed via the conveyor belt 17, the transfer paper is held and pressed to fix the transferred toner image. The cleaning device 12 removes the photoreceptor drum 7.
The toner remaining on the surface of the photoreceptor drum is removed, and the static elimination lamp is configured to eliminate the electric charge remaining on the surface of the photoreceptor drum using static elimination light. The main motor M also includes a photosensitive drum 7, a developing roller 9a, each member of a cleaning device to be described later, and pressure rollers 13a and 13b.
It is designed to transmit driving force to. Further, the image reading section 6, charge eliminator 8, developing device 9, transfer charger 101, cleaning device 12 and main motor M described above are controlled in an image forming sequence as shown in FIG.

As shown in FIG. 3, in the main body 18 of the cleaning device 12, a toner blade 19 as a contact member, a cleaning brush 20 and a toner recovery screw 21 are provided, and the toner blade 19 and the cleaning brush 20 are connected to the photoreceptor drum, respectively. The tip extends in the longitudinal direction (axial direction) of the photoreceptor drum 7 , and its tip portion contacts the photoreceptor drum 7 . The toner blade 19 is made of polyurethane rubber with a rubber hardness of approximately 77'' and has a thickness of 3 mm and a convergence of approximately 0n+m, and is approximately 74'' with respect to the tangent to the photoreceptor drum 7.
It is attached to a support member 18a that is rotatably provided with respect to the main body 18 so as to have an inclination angle of . The cleaning brush 20 is constructed of a conductive fur brush made of acrylic fibers subjected to conductivity treatment, and is attached to the main body 18 so that its tip part bites into the photoreceptor drum 7 by about 1.5 mm. The main body 18 is adapted to collect residual toner scraped off by a toner blade 19 and a cleaning brush 20, and the collected toner is transported to a toner collection tank (not shown) by a toner collection screw 21. ing. Further, as shown in FIG. 4, a control means 22 is provided at one end of the support member 18a.
a is adapted to rotate with respect to the main body 18 by means of a control means 22.

This control means 22 includes a solenoid 23, a pressure lever 24,
It is composed of a pressure arm 25 and an angle 26. The solenoid 23 is activated when removing the toner on the photoreceptor drum 7 based on an output signal from a controller (not shown), and moves the toner blade 19 onto the photoreceptor drum via the pressure lever 24, the pressure arm 25, and the angle 26. 7 with a pressure of about 45 gf/am, and when the solenoid 23 is not operating, that is, when toner removal work is not being performed, the pressure is about 5 gf/am.
The contact is made with a pressing force of aa. The reason why the toner blade 19 is set to contact the photoreceptor drum 7 with a pressing force of 45 gf/1 when removing residual toner is to ensure that the residual toner is removed as shown in FIG. This is because the pressure may be at least 20 gf/cm, preferably at least 30 gf/a++. Further, since the toner blade 19 is brought into contact with the photoreceptor under a pressure of about 5 gf/Cm when not in operation, the toner blade 19 is in uniform contact with the photoconductor in the longitudinal direction.

Next, the effect will be explained.

When an electrostatic latent image is formed by the image reading unit 6 on the photosensitive drum 7 whose surface is charged by the charging charger, this electrostatic latent image is made visible by the developing device 9 and then converted into a visible image by the transfer charger 10. Transferred to transfer paper. After this,
Since toner remains on the surface of the photosensitive drum 7 in the development area, that is, the image forming area, this toner is removed by the cleaning device 12. At this time, the controller outputs a signal to the solenoid 23 just before the tip of the image forming area reaches the cleaning device 12, so the solenoid 23 controls the toner blade 19 via the pressure lever 24, pressure arm 25, and angle 26. The photosensitive drum 7 is brought into contact with a pressure of about 45 gf/cm. Therefore, as shown in FIG. 6(a), the residual toner on the photoreceptor drum 7 is removed by the cleaning brush 20 in advance.
After being scraped off by the toner blade 19, the toner is scraped off with sufficient pressure, and the toner is collected into the main body 18. -Next, when the rear end of the image forming area passes through the cleaning device 12 and the toner removal work is completed, the signal output from the controller to the solenoid 23 is cut off, so the solenoid 23 returns to its original state. . Therefore, the toner blade 19 comes into contact with the photosensitive drum 7 with a pressing force of about 5 gf/application (see FIG. 6(b)).

Therefore, the toner collected in the main body 18 and the toner floating between the photoreceptor drum 7 and the cleaning device 120 are not scattered toward the photoreceptor drum 7.

As described above, in this embodiment, the control means 22 controls the toner blade 19 at a rate of about 45 gf/during the residual toner removal operation.
While contacting the photoreceptor drum 7 with a pressing force of cm,
Since the toner blade 19 is brought into contact with the photoreceptor drum 7 with a pressure of 5 gf/cm during non-operation, the toner blade 19 can be brought into contact with the photoreceptor drum 7 only during the toner removal operation, and the photoreceptor drum 7 is The photosensitive drum 7 can be used for a long period of time by preventing early wear. Therefore, it is possible to prevent the film thickness of the photoreceptor drum 7 from decreasing and deterioration of electrostatic properties, etc., and to form good images over a long period of time, thereby significantly extending the life of the photoreceptor drum 7. can be improved. Further, when the toner blade 19 separates from the photoreceptor drum 7, toner collected in the main body 18 and toner floating between the photoreceptor drum 7 and the cleaning device 12 are scattered toward the photoreceptor drum 7. It is possible to prevent the toner from adhering to the charge removal device 8, the photoreceptor drum 7, etc. For this reason, it is possible to form a good image without the charging device 8 becoming dirty and removing it, thereby preventing the amount of charging light from decreasing or the amount of exposure from decreasing. In addition to this, it is also possible to prevent the inside of the image forming apparatus 1 from becoming dirty.

Further, in this embodiment, since the toner blade 19 is brought into contact with the photoreceptor drum 7 with a pressing force of about 45 gf/cm during the work of removing residual toner, the photoreceptor drum 7 has a higher pressure than the conventional one, as shown in FIG. 7, and can process more than 100,000 copies. In addition to this, the photoreceptor drum 7 is applied with a pressure of 5gf/an when not in operation! Since this contact is made, problems such as dirt and removal of the charge removing device 8 due to toner scattering and a decrease in the amount of charging light did not occur. Note that in this embodiment, the toner blade 19 is moved approximately 4 times
It is brought into contact with the photoreceptor drum 7 with a pressure of 5 gfl■, and is brought into contact with the photoreceptor drum 7 with a pressure of 5 gf/cm during non-operation, and is not limited to this, but with a pressure of about 20 gf/cm during removal work. It is sufficient to contact the photoreceptor drum 7 with a pressing force of 10 gf/cm or less during non-operation.

〔effect〕

According to the present invention, the control means causes the contact member to contact the image carrier with a predetermined pressure during the residual toner removal operation, and to contact the image carrier with a pressure equal to or less than the predetermined pressure during non-operation. Therefore, the contact member can be brought into contact with the image carrier only during toner removal work, and the image carrier can be used for a long period of time by preventing early wear of the image carrier. can. Therefore, it is possible to prevent the film thickness of the image carrier from decreasing and deterioration of electrostatic properties, etc., and to form good images over a long period of time, greatly improving the life of the image carrier. I can do it. Furthermore, when the contact member separates from the image carrier, toner collected in the cleaning device or floating between the image carrier and the cleaning device may be scattered toward the image carrier. It is possible to prevent the toner from adhering to the charge eliminator, the image bearing member, and the like. Therefore, it is possible to form a good image without the charging device becoming dirty and removing the charging light, thereby preventing the amount of charging light from decreasing or the amount of exposure from decreasing. In addition to this, it is also possible to prevent the inside of the image forming apparatus from becoming dirty.

[Brief explanation of the drawing]

1 to 7 are diagrams showing an embodiment of the cleaning device according to the present invention, FIG. 1 is a configuration diagram of an image forming apparatus equipped with the cleaning device, and FIG. 2 is a sequence of the image forming operation. 3 is a block diagram of the cleaning device, FIG. 4 is a block diagram of its control means, FIG. 5 is a diagram showing the relationship between the drum residual toner rank and the pressing force of the toner blade, and FIG. 6 is a block diagram of the cleaning device. (a) is a diagram showing a state in which the toner blade is in contact with the photoreceptor drum with a predetermined pressure;
FIG. 6(b) is a diagram showing a state in which the toner blade contacts the photosensitive drum with a pressure less than a predetermined pressure;
The figure shows the relationship between the number of copies and the film thickness of the photoreceptor. 7... Photosensitive drum (image carrier), 12...
... Cleaning device, 19 ... Toner blade (contact member), 22.
...control means. Agent: Patent Attorney (Part 1) Figure 1B Figure 2 Static Elimination Lamp Figure 3 Figure 4, 19 Figure 5 Blade Pressure Rut 7cm) Figure 6 (a) Figure 6 (b) Figure 7 Copy Number of sheets

Claims (1)

[Claims] A cleaning device that has a contact member that contacts the image carrier and removes toner remaining on the image carrier with the contact member after the toner image formed on the image carrier is transferred to transfer paper, Bringing the contact member into contact with the image carrier with a predetermined pressure during the residual toner removal operation,
1. A cleaning device comprising a control means for bringing the image carrier into contact with a pressure equal to or less than a predetermined pressure during non-operation.