JP2798807B2 - Developer carrier, copying machine and facsimile using the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention is used in the field of technology for developing an electrostatic latent image with a developer, and is particularly used when developing with a magnetic force constraining the developer. Developer carrier.

[Prior Art] As electrophotography, US Pat. No. 2,297,691 is described,
As described in JP-B-42-23910 and JP-B-43-24748, a number of methods are known. They generally use a photoconductive substance to form an electric latent image on a photoreceptor by various means, and then develop the latent image using toner, and if necessary, to a transfer material such as paper. After the transfer of the toner image, the toner image is fixed by heating, pressure, solvent vapor or the like to obtain a copy.

Various methods for visualizing an electric latent image using toner are also known.

For example, the magnetic brush method described in U.S. Pat. Many developing methods such as a liquid developing method are known.

Among these developing methods, a dry developing method using a toner in a powder state is widely used from the viewpoint of easy handling of the developer.

As a developer carrier used in these methods, for example, as shown in JP-A-57-66455, a metal such as aluminum, nickel, corrosion-resistant steel (stainless steel), an alloy thereof or a compound thereof is formed in a cylindrical shape. In general, a material which is molded to a predetermined surface and treated so as to have a predetermined surface roughness by electrolysis, blasting, sanding or the like is widely used.

The developer carrier as described above is inexpensive and can form a high quality image relatively stably. On the other hand, in the case of using a single-component developer in which charging is performed by friction between the developing carrier and the toner, it is difficult to adjust the charging of the toner. The problem with the non-uniformity of these has not been completely solved.

Particularly, in the developing step, the developer existing near the surface of the developer carrier in the developer layer formed on the surface of the developer carrier by the regulating member has a very high charge (about 25 μC / absolute value).
g or more), there has been a situation in which the developer layer is bipolarized into a developer having a high charge and a developer having a low charge.

The developer having a high charge easily adheres to the surface of the developer carrying member, causing image density unevenness.

[Problems to be Solved by the Invention] An object of the present invention is to provide a developer carrier without the above-mentioned disadvantages, that is, the developer present on the developer carrier has a uniform charge and is used repeatedly. It is another object of the present invention to provide a developing carrier capable of obtaining a stable image.

[Means for Solving the Problems] That is, the present invention provides a coating layer containing a positively chargeable resin for a developer used for development, a carbon-based conductive material, and a negatively chargeable substance for the developer. A developer carrying member characterized by being provided on the surface.

Examples of the positively chargeable resin used in the present invention include various materials such as a phenol resin, an epoxy resin, and a polycarbonate resin. Generally, any material may be used as long as it is a substance that causes a triboelectric charge to the positive polarity with respect to the developer. .

Of these, thermosetting resins are preferred in terms of hardness and durability, and in terms of coating hardness and adhesion to a substrate,
Phenolic resins are most preferred. Such phenolic resins include a pure phenolic resin formed from phenol and formaldehyde, and a modified phenolic resin obtained by combining an ester gum and a pure phenolic resin, all of which can be used in the present invention.

In addition, since a phenolic resin forms a dense three-dimensional crosslinked structure by a thermosetting reaction, a very hard coating film can be formed as compared with other thermosetting resins (polyurethane, polyamide, etc.). And can be more preferably used.

Examples of the carbon-based conductive material used in the present invention include carbon black and graphite. Among them, a substance having low resistance is preferable from the viewpoint of film properties, and
Carbon black having a resistance value of 0.5 Ω · cm or less under a pressure of 0 kgf / cm ² is preferable.

The addition amount of such carbon black is preferably 5 to 50 parts by weight based on 100 parts by weight of the resin.

It is also possible to use several types of carbon black in combination.

Further, in the present invention, a negatively chargeable substance which is negatively charged by friction with a developer used for development can be added. By adding this negatively chargeable substance, it is possible to increase the number of developers having an electric charge (absolute value: 2.5 to 10 μC / g) suitable for development, and as a result, to achieve a stable high even in repeated use. A high-quality image can be obtained.

Material work function Wf (eV) and developer work function Wft
(EV) preferably satisfies the following relationship.

0 <(Wf−Wft) ≦ 5 (eV) Examples of the negatively chargeable additive having a work function value in the above range include the following: polytetrafluoroethylene resin, polyethylene resin, silicon Resin, polyvinyl butyral resin, polyacrylonitrile resin, polyvinyl chloride resin, and polychlorinated butadiene resin. Among them, preferred additives are polytetrafluoroethylene (polytetrafluoroethylene) resin,
Polyethylene resin and silicone resin.

The additive substance is usually used in the form of a powder, and the average particle size is usually selected to be 0.1 to 15 μm, preferably 0.1 to 5 μm.

The amount of addition is 1 to 20 parts by weight based on 100 parts by weight of the resin.
Parts by weight are preferred.

As the carrier substrate used in the present invention, a nonmetallic substance can be used in addition to the metal or alloy compound.

However, in the present invention, since the sleeve is used as an electrode in the configuration of the device, it is premised that the non-metallic material, for example, a plastic molded product or the like be configured to be energized when it is used as the carrier base. For example, a metal may be adsorbed on the surface by vapor deposition or the like, or may be made of a conductive resin.

In the present invention, a developer layer is further formed on the developer carrier at the time of the development step, and the thickness of the layer is preferably set to 10 to 100 μm, particularly preferably 20 to 50 μm, by the regulating member. I do.

The developer carrier of the present invention is widely used not only for electrophotographic copying machines but also for electrophotographic applications such as laser beam printers, CRT printers, LED printers, liquid crystal printers, printers for laser plate making and facsimile. Can be.

Among the developer carriers of the present invention, examples of the developer carrier having no photosensitive layer 2 include a substrate provided with a dielectric layer for holding an electrostatic latent image or a toner image on a support 4. so,
In addition, the dielectric layer and / or a protective layer containing a high-molecular-weight polyester resin and a cured resin of the present invention, particularly a photoion-curable resin, is formed on the surface of the dielectric layer.

Examples of the application of the developer carrier having no photosensitive layer 2 include:
Examples include a toner layer, an intermediate transfer member of an electrostatic latent image, and an electrostatic recording member.

FIG. 4 shows a schematic configuration of a general transfer type electrophotographic apparatus using a drum type photoreceptor on which the developer carrying member of the present invention is mounted.

In FIG. 4, reference numeral 41 denotes a drum-type photosensitive member as a developer carrying member, which is driven to rotate around an axis 41a in a direction of an arrow at a predetermined peripheral speed. During the rotation of the photoconductor 41, the peripheral surface thereof is uniformly charged with a predetermined positive or negative potential by a charging unit 42, and then, in an exposure unit 43, a light image exposure L ( Slit exposure, laser beam scanning exposure, etc.). As a result, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor.

The electrostatic latent image is then developed with toner by developing means 44,
The toner developed image is sequentially transferred by a transfer unit 45 from a paper supply unit (not shown) to the surface of the transfer material P fed between the photoconductor 41 and the transfer unit 45 in synchronization with the rotation of the photoconductor 41. Is done.

The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 48, subjected to the image fixation, and printed out as a copy outside the machine.

The surface of the photoreceptor 41 after the image transfer is cleaned and cleaned to remove the untransferred toner by the cleaning means 46, and is repeatedly used for image formation.

As the uniform charging means 42 for the photoconductor 41, a corona charging device is generally widely used. As the transfer device 45, corona transfer means is widely and generally used. As an electrophotographic apparatus, of the above-described components such as the photoreceptor 41, the developing unit 44, and the cleaning unit 46, a plurality of components are integrally connected as an apparatus unit, and this unit is detachably attached to the apparatus body. May be configured. For example,
The photoconductor 41 and the cleaning unit 46 may be integrated into a single device unit, and may be configured to be detachable using a guide unit such as a rail of the device body. At this time, the above-described device unit may be configured with the charging unit 42 and / or the developing unit 44.

In the case where the electrophotographic apparatus is used as a copier or a printer, the light image exposure L reads reflected light from the original, transmitted light or the original and converts the read signal into a signal. This signal is used to scan a laser beam and drive the light emitting diode array. Alternatively, it is performed by driving a liquid crystal shutter array or the like.

When used as a facsimile printer, the light image exposure L is an exposure for printing received data. FIG. 5 is a block diagram showing one example of this case.

In FIG. 5, a controller 51 includes an image reading unit 50.
And the printer 59 are controlled. The whole controller 51 is CP
It is controlled by U57. Data read from the image reading unit is transmitted to the partner station through the transmission circuit 53.

Data received from the partner station is sent to the printer 59 through the receiving circuit 52. The image memory 56 stores predetermined image data. Printer controller 58 is a printer
Controlling 59. 54 is a telephone.

The image received from the line 55 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 52, and then decoded by the CPU 57 to be sequentially stored in the image memory 56. You. When an image of at least one page is stored in the image memory 56, the image of the page is recorded. The CPU 57 reads out the image information for one page from the image memory 56 and sends out the decoded image information for one page to the printer controller 58. When receiving the image information of one page from the CPU 57, the printer controller 58 controls the printer 59 so as to record the image information of the page. Note that the CPU 57 is receiving the next page during recording by the printer 59.

As described above, image reception and recording can be performed by using the electrophotographic apparatus equipped with the developer carrier of the present invention as a printer.

Hereinafter, the present invention will be described in detail with reference to examples. Further, all “parts” described below are parts by weight. The work function value of the negatively chargeable single component developer used is 4.9 eV.

Example 1-Positively chargeable resin: 100 parts of phenolic resin-Carbon-based conductive material: 30 parts of carbon black-Negatively chargeable substance: 5 parts of polytetrafluoroethylene (average particle diameter: 0.6 μm) After being added to butanol so as to have a content of 30 wt% based on the minute content, the mixture was further mixed with glass beads and mixed and dispersed using a paint shaker for 2.5 hours. After mixing and dispersing, a nylon sieve (mesh 300 μm)
It was made into a paint by filtration using. After applying this on the developer carrier base by the air spray method,
The resultant was dried by heating at 150 ° C. for 30 minutes to form a phenol resin layer having a thickness of 15 μm.

Using this carrier and the negatively chargeable single-component developer, the charge distribution of the developer present on the carrier was measured. The result is shown in FIG.

Example 2 A negatively chargeable substance was polyethylene resin (average particle size: 3 μm)
The same measurement was carried out using a developer carrying member prepared in the same manner as in Example 1 except for changing to. The result is shown in FIG.

Example 3 The same measurement was carried out using a developer carrier produced in the same manner as in Example 1 except that the negatively chargeable substance was a silicone resin (trade name: Tospearl (manufactured by Toshiba Silicone Co., Ltd.)). The result is shown in FIG.

Comparative Example 1 The same measurement was performed using a developer carrier produced in the same manner as in Example 1 except that a blast treatment was performed on an aluminum substrate so as to have an equivalent surface instead of the coating layer of the present invention. Was performed. The result is shown in FIG.

Comparative Example 2 The same measurement was performed using the same developer carrying member as in Example 1 except that no negatively chargeable substance was contained. FIG. 3 shows the results.

FIGS. 1 to 3 show that: By providing a coating layer containing a positively chargeable resin, a carbon-based conductive material and a negatively chargeable substance on the surface of the developer carrying member, The charge distribution of the developer layer on the body can be made uniform and narrow, and the charge distribution of the developer layer can be adjusted to a range of charges (-
2.5 to 10 μC / g).

As a result, a stable image can be continuously formed even in an area with an extremely large number of durable sheets.

[Effects of the Invention] According to the present invention, by forming the above-mentioned coating layer on the base of the developer carrying member, the developer laminated on the coating layer can be charged stably and uniformly. As a result, high quality images can be obtained over a long period of time.

[Brief description of the drawings]

[Types of Drawings] FIG. 1 is a diagram showing the relationship between the charge density in the developer of the present invention and the frequency of toner on the carrier. FIG. 2 is a diagram showing the relationship between the charge density of the developer of Comparative Example 1 and the frequency of toner on the carrier. FIG. 3 is a diagram showing the relationship between the charge density in the developer of Comparative Example 2 and the frequency of toner on the carrier. FIG. 4 is a schematic configuration diagram of a transfer type electrophotographic apparatus equipped with a general drum type electrophotographic photosensitive member, and FIG. 5 is a block diagram of a facsimile system using the electrophotographic apparatus as a printer. [Main symbols in the drawings] 1 ... Example 1 2 ... Example 2 3 ... Example 3 41 ... Drum type photoreceptor, 42 ... Charging means, 43 ... Exposure unit, 44 ... Development Means 45 transfer means 50 image reading section 51 controller 52 receiving circuit 53
Transmission circuit, 54: Telephone, 55: Line, 56: Image memory, 57: CPU, 58: Printer controller, 59:
printer.

Claims (6)

(57) [Claims] 1. A development comprising a coating layer containing a resin positively charged with respect to a developer used for development, a carbon-based conductive material and a substance negatively charged with respect to said developer. Agent carrier. 2. The developer carrier according to claim 1, wherein the work function Wf (eV) of the negatively charged substance and the work function Wft (eV) of the developer satisfy the following relationship. 0 <(Wf−Wft) ≦ 5 (eV) 3. The developer carrier according to claim 1, wherein the weight ratio of the positively charged positive resin to the negatively charged substance is the former / the latter = 100/1 to 100/20. 4. A unit is formed by integrally supporting the developer carrier according to claim 1 and at least one of a charging unit, a developing unit, and a cleaning unit, and is a single unit detachable from the apparatus main body. An electrophotographic apparatus unit, characterized in that: 5. An electrophotographic apparatus comprising: the developer carrier according to claim 1; a latent image forming unit; a unit for developing the formed latent image; and a unit for transferring the developed image to a transfer material. . 6. An electrophotographic apparatus comprising the developer carrier according to claim 1, a latent image forming means, and a means for transferring a developed image to a transfer material, and a receiving means for receiving image information, comprising a remote terminal. A facsimile characterized by having.