JPH03196083A - Electrophotographic copying 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 [Field of Industrial Application] The present invention relates to an image forming apparatus using an electrophotographic process such as an electrophotographic copying machine and a printer, and particularly to a cleaning mechanism thereof.

[Prior Art] In a well-known image forming apparatus that repeats the process of transferring a toner image electrostatically formed on an image carrier onto a sheet-like transfer material mainly made of paper, the total amount of toner used to form the toner image is Since the toner is not necessarily transferred to the transfer material each time the toner is transferred, it is essential to sufficiently remove the residual toner remaining on the surface of the image carrier each time the toner is transferred.

Conventionally, as a cleaning means for this purpose, a cleaning blade made of an elastic material such as rubber is used, and one edge of the cleaning blade is brought into contact with the surface of the image carrier to scrape off the toner that reaches this area. What is configured is
It is well known that it has been widely put into practical use.
1. #)t,)-+-It is thought that this is due to its excellent inspection function.

This will be explained below according to the figures.

FIG. 2 (1) is a sectional view schematically showing the configuration of a typical leaning mechanism, in which the axis of the cylindrical image carrier 1 extends perpendicular to the plane of the paper and rotates in the direction indicated by the mark. A cleaning mechanism 2 is arranged close to each other parallel to the direction. One edge lla of the free edge of the cleaning blade 11 attached to the mechanism is in contact with the surface of the image carrier 1, and is not attached to the surface of the image carrier 1 at a transfer site (not shown) without contributing to the transfer. When the remaining toner reaches the contact edge lla of the cleaning blade 11 as it rotates, it is scraped off by this.

At this time, the free end edge of the cleaning blade 11 is often brought into contact with the image carrier 1 in the direction shown in the figure (in the counter direction with respect to the rotational direction of the image carrier 1). Although it is effective for removing

That is, the contact edge ll of the cleaning blade 11
In order for a to perform a stable cleaning function, it must come into contact with the surface of the image carrier 1 with uniform pressure over its entire length. It is unavoidable that corona products due to the presence of high-voltage members in the apparatus, paper powder, and deposits from the corona particles may adhere to the image carrier 1, resulting in unevenness.

Due to this cause, the friction between the cleaning blade 11 and the surface of the image carrier 1 becomes extremely large, and as shown in FIG. Contact with the image carrier 1 may cause the cleaning function to be lost.Especially in the case where the photosensitive layer on the surface of the image carrier 1 is formed of an organic semiconductor, the surface of the photosensitive layer and the cleaning blade 11 may be lost. Since the friction between the cleaning blade 11 and the cleaning blade 11 is greater than in the case of an inorganic photoreceptor, the cleaning blade 11 is likely to slip.

In addition, in the case of non-magnetic developers, which have been increasingly used as multi-color copying has become popular in recent years, there is a tendency for poor cleaning and cleaning blade curling to occur from both ends of the cleaning blade 11. It is clear that

Moreover, paper powder that has not been completely cleaned and adheres to the surface of the image carrier 1 is repeatedly used due to corona charging.
When moisture is absorbed, the electrical resistance decreases significantly, and as a result, image blurring and image deletion may occur.

In cleaning using the cleaning blade 11,
Toner may slip through due to damage or vibration of the cleaning blade 11, leading to poor cleaning. This tendency is particularly noticeable when a toner with a small average particle size is used.

In addition, when cleaning using a cleaning blade, the friction coefficient between the blade and the surface of the image carrier is relatively large, so it can be used for a long time! gJt Japan A - Polishing of the protruding surface It is difficult to obtain stable images.

In order to avoid such drawbacks, for example,
As seen in Japanese Patent No. 212881, it has been proposed to cut off both ends of the blade that contacts the image carrier. However, there were unavoidable defects that caused particles to scatter from the edges and contaminate the transfer material and various parts within the device.

[Problems to be Solved by the Invention] The present invention has been made to deal with the above-mentioned situation, and is designed to provide stable cleaning at all times without causing the cleaning blade to slip or toner to slip through in the cleaning mechanism. The object of the present invention is to provide an electrophotographic apparatus that can perform the following tasks.

Furthermore, the present invention has a cleaning mechanism that stably removes paper dust and the like to prevent image blurring and image blurring.
It is also intended to fill the 60-year-old Yukikan mutual blind police station with Tsuji Oru 7.

A further object of the present invention is to provide an electrophotographic apparatus in which friction and abrasion of the surface of an image carrier can be reduced in a cleaning mechanism.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a cleaning mechanism that performs cleaning by bringing a belt-like cleaning member into contact with an image bearing member, in which the belt-shaped cleaning member contacts the image bearing member. The fabric is characterized in that at least a part of the fabric is made of ultrafine fibers having a thickness of 15 μm or less.

By doing so, even toner having a small particle size can be efficiently cleaned from the surface of the image carrier, and the cleaning blade cannot be turned over.

The configuration of the present invention will be explained below based on the drawings.

Cleaning mechanism 2 that can be installed in the electrophotographic apparatus of the present invention
is characterized in that at least a part of the belt-like cleaning member 3 in the area where it comes into contact with the image carrier 1 is a woven fabric made of ultra-fine fibers.

FIG. 1 is a schematic cross-sectional view showing the configuration of an electrophotographic apparatus used in the present invention.

A cleaning mechanism 2 is arranged close to and parallel to the axial direction of a cylindrical image carrier 1 that extends perpendicular to the plane of the paper and rotates in the direction of the arrow. A portion of the cloth 3 is in contact with the surface of the image carrier 1. The loop of the belt-like cleaning member 3 is supported by a plurality of support rollers. When the toner remaining on the surface of the image carrier 1 without contributing to the transfer at the transfer site 10 reaches the cleaning mechanism 2 as the image carrier 1 rotates, it is cleaned by the woven fabric 3 made of ultra-fine fibers of the mechanism 2. It is cleaned by rubbing with.

At this time, a loop-shaped woven cloth 3 serving as a cleaning member moves in a direction opposite to the rotational direction of the image carrier 1 to clean the residual toner on the surface of the image carrier 1, and this toner is removed from the dust box 12. It is designed to fall inside.

With this configuration, residual toner on the surface of the image carrier 1 is always cleaned by the clean surface of the belt-shaped cleaning member 3 made of a woven fabric made of ultra-fine fibers.

According to the present invention, since cleaning is performed using a belt-like cleaning member, even if small particle size toner is used under strict cleaning conditions, toner slip-through and blade turning-up, as seen in blade cleaning, cannot occur. .

As the ultrafine fibers used in the present invention, fibers with a diameter of 15 μm or less, preferably 10 LLm or less are used. Examples of the fiber material include polyester, nylon, polyacrylonitrile, polyurethane, and mixtures thereof.

When attached to the belt-like cleaning mechanism 2 made of ultra-fine fibers and placed in contact with the image carrier 1, the cleaning member made of a woven fabric made of synthetic fibers of ordinary thickness (thickness of several tens of micrometers) Even dirt that may slip off the surface of the image carrier 1 can be cleaned extremely efficiently if the cleaning member is made of a woven fabric made of ultra-fine fibers.

Furthermore, by selecting the thickness of the ultra-fine fibers according to the particle size of the toner on the image carrier 1, it is possible to carry out appropriate leaning of the layer.

Examples of photoreceptors to which the cleaning mechanism of the present invention can be effectively applied include silicon photoreceptors and organic photoreceptors. Other examples include inorganic photoreceptors such as selenium, zinc oxide, cadmium sulfide, selenium-tellurium, and selenium-arsenic.

Examples of organic photoreceptors include organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene; and low-molecular organic photoconductors such as carbazole, anthracene, pyrarizones, oxadiazoles, hydrazones, and polyarylalkanes. and phthalocyanine pigments,
Organic pigments and dyes such as azo pigments, cyanine dyes, polycyclic quinone pigments, perylene pigments, indigo dyes, thioindigo dyes, squaric acid, and methine dyes are known. In particular, organic pigments and dyes with photoconductivity are easier to synthesize than inorganic materials, and the variety of compounds that exhibit photoconductivity in an appropriate wavelength range has been expanded. Conductive organic pigments and dyes have been proposed.

For example, US Pat. No. 4,123,270, US Pat. No. 42,476
No. 14, No. 4251613, No. 4251614, No. 4256821, No. 4260672, No. 4268596, No. 4278747, No. 429
As disclosed in the specification of No. 3628, etc., electrophotographic photoreceptors are known that use a disazo pigment exhibiting photoconductivity as a charge generation substance in a photosensitive layer that is functionally separated into a charge generation layer and a charge transport layer. There is.

In the electrophotographic apparatus of the present invention, since cleaning is performed by bringing a woven fabric made of fibers into contact with the image carrier l as the belt-like cleaning member 3, the blade does not turn over as would occur in blade cleaning. . Further, the use of a belt-shaped cleaning member made of ultra-fine fibers is useful, and it is possible to efficiently clean dirt such as toner and paper dust on the surface of the image carrier 1.

As a result, good image quality can be maintained even after repeated copying many times, with almost no background smudges, image blurring, or smearing caused by durability tests.

Furthermore, unlike cleaning mechanisms that require high contact pressure to the image carrier due to the use of cleaning blades, rollers, etc., a belt made of fibers is used for the contact part with the image carrier. Because of this, the low coefficient of friction between the image carrier and the image carrier is useful, and the surface of the image carrier is less likely to be scratched even after repeated durability tests. For this reason, the cleaning mechanism installed in the electrophotographic apparatus of the present invention can be said to be a leaning mechanism, which is particularly advantageous for organic photoreceptors, which are inferior to inorganic photoreceptors in terms of wear resistance.

Example 1 The belt-shaped cleaning member 3 attached to the cleaning mechanism 2 shown in FIG. 2 was created.

In the cleaning mechanism 2, the image carrier 1 to which the belt-shaped cleaning member 3 made of woven cloth made of ultra-fine fiber comes into contact is an aluminum cylinder with a diameter of 80 mm, on which a photosensitive layer having the following structure is formed. used.

Ammonia aqueous solution of casein (11.2 gr of casein, 1 gr of 28% ammonia water) was placed on the surface of the cylinder.

222 ml of water) was applied by a coating method and then dried to form a subbing layer with a coating amount of 1.0 gr/m2.

Next, 1.0 parts by weight of a charge generating substance represented by the formula below, 1 part by weight (manufactured by Gakusei) and 30 parts by weight of isopropyl alcohol were mixed and dispersed for 4 hours using a ball mill dispersion machine, and this dispersion was applied to the undercoat layer. A charge generation layer was formed by applying the coating to the surface of the substrate using a dip coating method and drying it. The thickness of the obtained film was 0.3μ
It was m.

Next, 1 part by weight of a charge transport substance represented by the following formula, 1 part by weight of a polycarbonate resin (trade name: Kneepilon, manufactured by Mitsubishi Gas Chemical)
Parts by weight and 6 parts by weight of dichloromethane were mixed and dissolved by stirring with a stirrer.

This liquid was applied onto the charge generation layer by dip coating and dried to form a charge transport layer. The thickness of the obtained film was 17 μm. This photoreceptor drum is referred to as photoreceptor 1.

The photoreceptor 1 constructed as described above and toner having an average particle size of 8 μm are cleaned using the cleaning mechanism 2 described above.
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When a durability test of 0,000 sheets was carried out, no cleaning failure occurred, and an image equivalent to the initial image could be obtained until the end. In addition, the film thickness of the charge transport layer after a durability test of 50,000 sheets was 16.5 μm (initially 1
7 μm), and the scraped thickness remained at 0.5 μm.

Example 2 The belt-like cleaning member 3 attached to the cleaning mechanism 2 of Example 1 was made of 50% polyester, 50% nylon, and a thickness of 1 μm each as a woven fabric made of ultrafine fibers.
A durable image production test was conducted in the same manner as in Example 1 using the same photoreceptor drum 1 and toner as in Example 1, except that a fabric woven with threads of m was used. The results are shown in Table 1.

Example 3 The belt-shaped cleaning member 3 attached to the cleaning mechanism 2 of Example 1 was made of 55% polyester and 45% polyacrylonitrile as a woven fabric made of ultra-fine fibers.
The cleaning mechanism 2 was fabricated using a fabric woven with threads obtained from threads having a thickness of 10 μm.

The image carrier 1, on which the woven fabric made of ultrafine fibers constituting the belt-like cleaning member 3 attached to the cleaning mechanism 2 comes into contact, is an aluminum cylinder with a diameter of 80 mm, on the surface of which a photosensitive layer having the following structure is formed. I used the one I made.

Ammonia aqueous solution of casein (11.2 gr of casein, 1 gr of 28% ammonia water) was placed on the surface of the cylinder.

After applying 222 ml of water (222 ml of water) using a coating method, the coating amount is 1. A subbing layer of Ogr/m'' was prepared.

Next, 1.0 parts by weight of a charge-generating substance represented by the formula below, 1 part by weight of butyral resin (trade name Kosuretsu 8M-2, manufactured by Sekisui Chemical), and 30 parts by weight of isopropyl alcohol were mixed and dispersed for 4 hours using a ball mill dispersion machine. This dispersion was applied onto the undercoat layer by a dip coating method, and then dried to prepare a charge generation layer. The resulting film thickness was 0.3 μm.

1 part by weight of a charge transport substance represented by the following formula, 1 part by weight of polycarbonate resin (trade name: Niepiron, manufactured by Mitsubishi Gas Chemical), and 6 parts by weight of dichloromethane were mixed and dissolved by stirring with a stirrer.

This liquid was applied onto the charge generation layer by dip coating and dried to form a charge transport layer.

The obtained film thickness was 18 μm. This photoreceptor drum is referred to as a photoreceptor 2.

This constructed photoreceptor 2, toner with a particle size of 10 μm @
20 minutes in the same manner as in Example 1 using the cleaning mechanism of Mitsubishi F.
When a durability test of 1,000 sheets was conducted, no cleaning defects occurred until the end, and images equivalent to the initial images could be obtained. In addition, the thickness of the charge transport layer after a durability test of 50,000 sheets was 17.7 μm, and the abrasion thickness was 0.3 μm.
I stayed there.

Example 4 As the woven fabric 3 made of ultra-fine fibers constituting the belt-like cleaning member 3 in the cleaning mechanism 2 of Example 1, a fabric woven using threads made of 100% polyester fibers and fibers with a thickness of 10 μm. A cleaning mechanism 2 similar to that of Example 1 was prepared using the following.

As the image carrier 1 against which the belt-like cleaning member 3 made of a woven fabric made of ultra-fine fibers of the cleaning mechanism 2 comes into contact, a negatively charged α-3L photoreceptor having a diameter of 80 mm was used.

A paper passing durability test was conducted in the same manner as in Example 1 using the cleaning mechanism 2, image carrier 1, and toner in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 In place of the cleaning mechanism 2 equipped with the belt-like cleaning member 3 used in Example 1, a copying machine [NP-352
A durable image output test was conducted in the same manner as in Example 1 using the blade cleaning mechanism 2 used in [No. 5 (manufactured by Canon Inc.)]. The results are shown in Table 1.

[Effects of the Invention] The present invention is an electrophotographic apparatus in which, in the cleaning mechanism, at least a part of the belt-like cleaning member in the area where the belt-like cleaning member contacts the image carrier is made of a fabric made of ultrafine fibers having a diameter of 15 μm or less. Unlike an electrophotographic apparatus using a cleaning blade, not only can stable cleaning be performed at all times, but also the cleaning blade does not break or toner slips through.

In addition, the present invention improves the cleaning mechanism installed in the electrophotographic device so that it can stably remove paper dust, etc., which not only prevents image deletion and blurring but also prevents scratches on the surface of the image carrier. succeeded in reducing it.

[Brief explanation of drawings]

[Types of drawings] Fig. 1 is a schematic cross-sectional view showing the structure of the electrophotographic apparatus of the present invention, and Fig. 2 is a contact state when the cleaning blade is turned over in a known blade cleaning mechanism of a known blade cleaning system. FIG. [Main symbols in the diagram] 1... Image carrier 2... Cleaning device 3... Belt-shaped cleaning member 4... Support member 5... Pre-exposure 6... - Wide charger 7 ... Image exposure 8 ... Developing device 9 ... Paper feed roller 10 ... Transfer charger 11 ... Cleaning blade 11a ... Normal contact edge of cleaning blade 11b ... Turned blade Contact edge 12...
dust box.

Claims (4)

[Claims] (1) In the belt-shaped cleaning member of the cleaning mechanism that transfers the toner image formed on the surface of the image carrier to a transfer material and wipes off the toner remaining on the surface of the image carrier, at least the part that comes into contact with the image carrier An electrophotographic device characterized in that a portion thereof is made of an ultrafine fiber knitted fabric having a diameter of 15 μm or less. (2) The electrophotographic apparatus according to claim 1, wherein the particle size of the toner used is 10 μm or less. (3) The electrophotographic apparatus according to claim 1, wherein the image carrier is made of a silicon photoreceptor. (4) The electrophotographic apparatus according to claim 1, wherein the image carrier is an organic photoreceptor.