JPH1074026A - Cleaning device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device being reducible in size and preventing the occurrence of the wearing of a cleaning member, a deterioration in an image under a high humidity, etc., without using a magnet roller and an image forming device using the cleaning device. SOLUTION: In a cleaning device for removing a developing agent remaining on an image carrier using an amorphous silicon photoreceptor having a surface whose contact angle with pure water is >=50 deg., after an image with a developing agent is transferred, is composed to provide a cleaning member 8c for scraping a developing agent from the surface of an image carrier 1 and a housing part 8d for storing a scraped developing agent and rubbing the developing agent scraped by the cleaning member 8c on the image carrier 1 by a dead weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for removing a developer remaining on an image carrier when an image is formed by an electrophotographic recording method, and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic recording system has been adopted in a copying machine, a printer and the like. In the electrophotographic recording method, a sheet-shaped recording medium such as paper is brought into contact with an image carrier having an electrostatically formed image formed by a developer (hereinafter, referred to as “toner”) on the surface thereof to form the toner image. The step of transferring is repeated, but not all of the toner on the image carrier is transferred to the recording medium during the transfer of the toner image. Therefore, it is necessary to remove the toner remaining on the surface of the image carrier every time the toner is transferred.

As a cleaning device for removing the residual toner, a cleaning blade made of an elastic member such as rubber is conventionally pressed against the surface of the image carrier after the transfer of the toner image to scrape off the residual toner. As a suitable means when toner is used, a means sharing a magnet roller is used.

For example, as shown in FIG. 7, a cleaning device 51 is provided in the vicinity of an image carrier 50 that extends in a direction perpendicular to the plane of the drawing and rotates in the direction of arrow a. A cleaning blade 52 is attached to the cleaning device 51. The edge of one edge of the blade 52 is pressed against the surface of the image carrier 50, and the toner remaining without being completely transferred from the image carrier 50 to the recording medium. Is removed by scraping.

Further, a cleaning blade 52 shown in FIG.
Roller on the upstream side in the rotation direction of the image carrier 50
A roller 53 is provided, and the roller 53 rotates at a low speed.

In the cleaning device 51, when the toner remaining on the image carrier 50 is scraped off by the cleaning blade 52, the toner adheres to the surface of the magnet roller 53 to form a magnetic brush. The thickness becomes a predetermined thickness by 54 and reaches the portion close to the image carrier 50 again, and its surface is rubbed with a magnetic brush.

In the above-described cleaning device for forming a magnetic brush, the effect of removing deposits, corona products, and the like from the recording medium adhering to the surface of the image carrier is recognized. Part of the toner adhered by the magnetic brush is captured at the position of the magnetic brush, weakens the adhesive force of the passing toner to the image carrier 50, and supplies toner stably to the blade edge. Therefore, there is an effect that the load on the cleaning blade 52 can be reduced.

In particular, as in an image forming apparatus using an amorphous silicon photoreceptor as the image carrier 50, it has a surface which is highly hydrophilic and has a low surface energy substance, and can be used to print a large number of sheets under a high humidity environment. In the case where the image quality is easily deteriorated such as image deletion due to paper, it is preferable to prevent the image quality from being deteriorated by disposing the magnet roller.

[0009]

However, in the above-described cleaning device, a magnet roller is provided.
Since it is necessary to dispose the 53 near the image carrier 51, the entire apparatus including the cleaning blade 52 becomes large, and as a result, the image carrier 50 needs to have a large diameter. For this reason, the cost of an image carrier using amorphous silicon has been particularly high. In addition, it becomes difficult to separate the curvature of the recording medium during transfer separation, a forced separation means such as a corona charger is required, and it is also difficult to make the image carrier a process cartridge.

On the other hand, when the size of the magnet roller 53 is reduced in order to reduce the size of the apparatus, there is a problem that it is difficult to obtain a magnetic force sufficient to restrain the magnetic toner.

The present invention has been made to solve the above problems, and
It is an object of the present invention to provide a cleaning device that can be reduced in size without using a magnet roller and without causing abrasion of a cleaning member or image deterioration under high humidity, and an image forming apparatus using the cleaning device.

[0012]

A typical configuration according to the present invention for achieving the above object has a surface having a contact angle with pure water of 50 ° or more after transferring an image with a developer. In a cleaning device that removes the developer remaining on the image carrier using the amorphous silicon photoconductor, a cleaning member that scrapes the developer from the image carrier, and a storage unit that stores the scraped developer, Wherein the developer scraped off by the cleaning member slides on the image carrier by its own weight.

In the above construction, since the toner scraped off by the cleaning member becomes a toner pool on the image carrier and rubs on the image carrier, the cleaning member is turned up and the surface of the image carrier is scraped. Can be prevented, and the occurrence of image deterioration can be prevented. Further, since there is no need to use a magnet roller or the like, the size of the apparatus can be easily reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an image forming apparatus using a cleaning device according to an embodiment of the present invention will be described with reference to the drawings.

First Embodiment First, an image forming apparatus and a cleaning apparatus according to a first embodiment will be described with reference to FIGS. 1 is an overall schematic diagram of the image forming apparatus, FIG. 2 is an explanatory diagram of a toner removing state of a cleaning device, and FIG. 3 is an explanatory diagram of a toner removing state when a cleaning blade is arranged in a vertical direction. .

Here, the overall configuration of the image forming apparatus will be described first, and then the configuration of the cleaning device will be described.

<< Overall Description of Image Forming Apparatus >> As shown in FIG. 1, this electrophotographic image forming apparatus (laser beam printer) transmits information light based on image information from an optical system (not shown) to an electronic device as an image carrier. The latent image is formed on the photoconductor by irradiating the photoconductor drum 1, and the latent image is developed to form a toner image. Then, in synchronization with the formation of the toner image, the recording medium P is transferred from a cassette (not shown) to a transport roller 2.
The recording medium P is conveyed by a conveying unit including a recording medium P and a discharge roller 3, and a voltage is applied to the transfer roller 4 as a transfer unit for the toner image formed on the electrophotographic photosensitive member.
Transfer to Then, the recording medium P after the image transfer is conveyed from the pair of discharge rollers 3 to a fixing unit (not shown), and the fixing unit applies heat and pressure to fix the toner image on the recording medium P and discharges it to the discharge unit. Things.

In the image forming process, the photosensitive drum 1 is rotated, and its surface is uniformly charged by the primary charger 5.
The information beam 6 from the optical system is exposed to the photosensitive drum 1 to form a latent image, and the latent image is developed by the developing unit 7.

The photosensitive drum 1 is an amorphous silicon photosensitive drum. The photosensitive drum 1 is a rotating cylindrical photosensitive drum which rotates in the direction of arrow a in FIG. 1 at a process speed of 200 mm / sec and is perpendicular to the plane of FIG. It is configured. This amorphous silicon photoreceptor is placed on an aluminum cylinder
Plasma CVD of 30μm amorphous silicon photosensitive layer
Deposited by the method, the diameter is about 30mm.

The amorphous silicon photoreceptor has a surface having a contact angle with pure water of 50 ° or more and comprises at least a conductive substrate, a charge injection blocking layer, a photoconductive layer, and a surface layer. And / or a layer mainly composed of amorphous silicon containing halogen.

The amorphous silicon photoreceptor contains hydrogen and / or halogen and is selected from the group consisting of carbon, nitrogen, oxygen, a group III element and a group V element.
A surface layer made of amorphous silicon containing at least one species or amorphous carbon containing at least one selected from nitrogen, oxygen, a group III element and a group V element is formed. No means for heating the photoconductor is provided.

The developing means 7 sends out the toner T in the toner container, rotates the developing roller 7a, and forms a toner layer on the surface of the developing roller 7a to which a triboelectric charge is applied by the developing blade 7b. The toner image is formed by transferring the toner to the photosensitive drum 1 in accordance with the latent image, and the latent image is visualized.

The toner image is transferred to a recording medium P conveyed in synchronization with the rotation of the photosensitive drum 1 by applying a voltage having a polarity opposite to that of the toner image to a transfer roller 4, and the recording medium P is transferred. Is conveyed to the fixing means, and the transferred toner image is fixed and then discharged. In addition, as the transfer means, in addition to the roller-shaped transfer means as described above, a belt-shaped transfer means may be used. It is preferable because the transfer performance can be obtained.

On the other hand, on the photosensitive drum 1 after the transfer of the toner image, foreign matters such as toner and paper dust remaining on the drum 1 are removed by the cleaning means 8 and the pre-exposure means 9
Is performed again.

{Description of Cleaning Device} Next, the structure of the cleaning means 8 as a cleaning device will be described.

The cleaning means 8 is disposed vertically above the photosensitive drum 1. A cleaning blade 8b as a cleaning member and a toner squeeze sheet 8c are attached to a cleaning frame 8a, and the cleaning blade 8b scrapes the cleaning blade 8b. The collected toner T is sent to the collected toner storage section 8d in the toner frame 8a. At this time, the collected toner T slides on the photosensitive drum 1 by its own weight.

Here, the movement of the collected toner T collected by the cleaning means 8 will be described with reference to FIGS. First, as shown in FIG. 3, when the cleaning blade 8b is disposed beside (vertically) the photosensitive drum 1, the toner T scraped off by the cleaning blade 8b by its own weight as shown by an arrow J. , Falls intermittently downward, and is guided as it is to the collected toner storage unit. Therefore, the toner T collected on the blade 8b
Is not sufficiently supplied, the blade is turned up and the photosensitive drum 1
There is a risk of scraping of the steel. Therefore, in this case, it is necessary to provide a magnetic brush such as a magnet roller.

However, as shown in FIGS. 2A and 2B, when the cleaning blade 8b is disposed above the photosensitive drum 1 in the vertical direction, the toner T scraped off by the cleaning blade 8b cannot be used. It is accumulated between the cleaning blade 8b and the squeeze sheet 8c by its own weight. The accumulated toner T circulates in the direction of arrow R, and rubs the surface of the photosensitive drum 1 by this circulating motion.
Further, when the toner T is accumulated to some extent, it is sent over the blade 8b and is accumulated in the collected toner storage section 8d.

The ability of the toner T to rub the photosensitive drum 1 is determined by the cleaning blade 8b and the squeeze sheet 8c.
(Hereinafter referred to as “toner nip width”), and particularly when the toner nip width is 5 mm or more, a good effect is exhibited. In this embodiment, the diameter of the photosensitive drum 1 is 30 mm.
Because of the small diameter, the toner nip width is set to 5.5 mm.

The cleaning means 8 constructed as described above
When a durability test was performed on 250,000 sheets, no blade turning occurred without providing a magnetic roller or the like.
Also, the photoreceptor drum 1 was scraped by about 250 °, and there was no problem in image formation (as shown in FIG. 3, a cleaning unit 8 was arranged beside the photoreceptor drum 1 and a similar durability test was performed). The photoreceptor drum abrasion was 1000 mm.

Further, even when a durability test similar to that described above was performed under high humidity (32.5 ° C., 85%), no image deterioration was observed.

As described above, the cleaning device having the cleaning member for removing and collecting the toner and other foreign matters remaining on the amorphous silicon photoreceptor is disposed on the upper portion of the photoreceptor drum 1 so that the cleaning device is stably provided on the amorphous silicon photoreceptor. Thus, it is possible to supply a small-sized cleaning device capable of forming a formed toner layer, and it is possible to maintain a high cleaning property and obtain a great effect against image deterioration under high humidity.

Further, even with a non-magnetic toner which cannot be polished by a magnetic roller as a toner, the cleaning device having the above structure is effective for good cleaning properties and for preventing image deterioration under high humidity.

By adding a powder having a polishing effect, such as strontium titanate, silica, or alumina, to the toner, the effect on image deterioration under high humidity can be further improved.

[Other Embodiments] In the first embodiment described above, an example is shown in which the collected toner collected by the cleaning blade is sent to the collected toner storage section by rotation of the photosensitive drum 1, but FIGS. As shown in FIG. 6, a toner feeding member may be provided in the cleaning frame 8a. Hereinafter, the configuration of the cleaning device shown in FIGS. 4 to 6 will be sequentially described. In FIGS. 4 to 6, members having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 4, reference numeral 10a denotes a magnetic roller,
It has a function of collecting the magnetic toner sent on the cleaning blade 8b. A scraper 10b is provided in the vicinity of the magnetic roller 10a, whereby the thickness of the toner layer on the magnetic roller 10a is kept constant, and
Excess toner on 10a is dropped into the collected toner storage section 8d.

By providing the magnetic roller 10a and the scraper 10b in this manner, the cleaning blade 8b
Since the amount of the upper toner becomes constant and the photosensitive drum 1 can be rubbed stably even during long-term image formation, high cleaning performance can be maintained for a long time.

FIG. 5 shows an endless magnetic belt 11 rotatably provided in the cleaning frame 8a so that the magnetic toner T is conveyed by the magnetic belt 11 to the collected toner storage section 8d. is there.

In this way, a stable cleaning performance can be maintained, and a great degree of freedom can be provided in the transport direction of the collected toner T.

FIG. 6 shows the electromagnet 12 disposed within the toner nip width and at a position close to the photosensitive drum 1. In the embodiment of FIG. 6, the gap between the magnet 12 and the photosensitive drum 1 is set to 1 mm.

By bringing the magnet 12 close to the toner nip width as described above, the collected toner t can be held within the toner nip width even in the case of a low image density. The image density can be kept constant by turning on and off the electromagnet 12 according to the image density.

Incidentally, in the embodiment shown in FIG.
Is provided in the cleaning frame 8a.
When the cylinder is made of a material having a high magnetic permeability such as aluminum, the same effect can be obtained by disposing the magnet 12 on the inner surface side of the photosensitive drum 1.

[0043]

The present invention is constructed as described above.
The toner scraped off by the cleaning member becomes a toner pool on the image carrier and rubs on the image carrier, thereby preventing the turning of the cleaning member and the surface scraping of the image carrier,
Image degradation can be prevented from occurring. This allows
Even if an image carrier that easily causes image deletion or the like due to a large number of papers is used, it is possible to prevent the image quality from deteriorating. Further, since it is not necessary to use a magnet roller or the like, the size of the apparatus can be easily reduced, and the diameter of the image carrier can be easily reduced.

Therefore, in the image forming apparatus using the cleaning device, the cost of the image carrier can be easily reduced, the curvature of the recording medium can be separated, and the cartridge such as the image carrier can be formed. Can be easily realized.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of an image forming apparatus.

FIG. 2 is an explanatory diagram of a toner removal state of the cleaning device.

FIG. 3 is an explanatory diagram of a toner removal state when a cleaning blade is arranged in a vertical direction.

FIG. 4 is an explanatory diagram of an embodiment in which a magnetic roller is provided in a cleaning device.

FIG. 5 is an explanatory diagram of an embodiment in which a magnetic belt for conveying collected toner is provided in the cleaning device.

FIG. 6 is an explanatory diagram of an embodiment in which a magnet is provided in a cleaning device.

FIG. 7 is an explanatory diagram of a cleaning device according to a conventional example.

[Explanation of symbols]

 P ... recording medium T ... toner 1 ... photosensitive drum 2 ... transport roller 3 ... discharge roller 4 ... transfer roller 5 ... primary charger 6 ... information light 7 ... developing means 7a ... developing roller 7b ... developing blade 8 ... cleaning means 8a ... Cleaning frame 8b ... Cleaning blade 8c ... Squeeze sheet 8d ... Recovered toner container 9 ... Pre-exposure means 10a ... Magnetic roller 10b ... Scraper 11 ... Magnetic belt 12 ... Magnet

Claims (8)

[Claims] 1. A cleaning device for removing a developer remaining on an image carrier using an amorphous silicon photoreceptor having a surface having a contact angle with pure water of 50 ° or more after transferring an image with the developer. A cleaning member that scrapes developer from the image carrier; and a storage unit that stores the scraped developer, wherein the developer scraped by the cleaning member is on the image carrier by its own weight. A cleaning device configured to rub the surface. 2. The cleaning device according to claim 1, wherein the cleaning member is disposed vertically above the image carrier. 3. The cleaning device according to claim 1, further comprising a guide for guiding the developer scraped by the cleaning member to the storage section. 4. The image carrier according to claim 1, wherein the amorphous silicon photoreceptor comprises at least a conductive substrate, a charge injection blocking layer, a photoconductive layer and a surface layer, and these are made of amorphous silicon containing hydrogen and / or halogen. 2. The cleaning device according to claim 1, wherein the cleaning device comprises a main layer and does not include a means for heating the photoconductor. 5. The image carrier according to claim 1, wherein the amorphous silicon photoconductor contains hydrogen and / or halogen, and contains at least one selected from carbon, nitrogen, oxygen, a group III element and a group V element. Containing amorphous silicon or one selected from nitrogen, oxygen, a group III element and a group V element.
2. The cleaning apparatus according to claim 1, wherein a surface layer made of amorphous carbon containing at least one species is formed. 6. An image forming apparatus for transferring an image by a developer to form an image, comprising: an image carrier; a developing unit for developing a latent image formed on the image carrier with a developer; The cleaning device according to claim 1, further comprising: a transfer unit configured to transfer an image to a recording medium; and a cleaning unit remaining on the image carrier after the transfer. An image forming apparatus comprising: 7. The image carrier according to claim 1, wherein the amorphous silicon photoreceptor comprises at least a conductive substrate, a charge injection blocking layer, a photoconductive layer and a surface layer, and these are made of amorphous silicon containing hydrogen and / or halogen. 7. The image forming apparatus according to claim 6, wherein the image forming apparatus comprises a main layer and does not include a means for heating the photoconductor. 8. The image carrier according to claim 1, wherein the amorphous silicon photoconductor contains hydrogen and / or halogen, and contains at least one selected from carbon, nitrogen, oxygen, a group III element and a group V element. Containing amorphous silicon or one selected from nitrogen, oxygen, a group III element and a group V element.
7. The image forming apparatus according to claim 6, wherein a surface layer made of amorphous carbon containing at least one species is formed.