JPH0451273A - Developing device - Google Patents

Abstract

PURPOSE:To reduce fogging and the scattering of toner and to stably form an image by using a drum-like thin film member as a developing roller, providing a driving roller, coming in contact with the inner peripheral side surface of the member, at least on a part, and a magnetic field generating means inside the member, and pressing the member to a latent image carrier. CONSTITUTION:The developing roller 9 carrying the toner 8 is rotated/driven, and composed of the driving roller 10 having a rubbing member on an outer periphery, the thin film member 11, and the magnetic field generating means 12 included in it. The magnetic field generating means 12 holds the supplied toner 8 on the thin film member 11 by magnetic force, and reduces base fogging caused by the adhesive strength of unelectrified toner, the scattering of the toner, and the base fogging caused by the sticking of the toner having a great charge quantity per unitary mass to a nonimage part by image-force, etc. Further, a developing electric field can be emphasized by pressing the thin film member to the latent image carrier, and a gap between the latent image carrier and the thin film member is regulated by the thickness of a toner layer, so that the developing electric field is stabilized. The toner is held by the magnetic force, so that a high-density and high-resolution image can be stably formed without having the base fogging, even as a contact phenomenon.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device using -component magnetic toner.

[Prior Art] As disclosed in Japanese Unexamined Patent Publication No. 63-226676, a conventional developing device elastically attaches a surplus portion of a cylindrical thin film member sleeve having an excess circumferential length to a drive roller onto a photoreceptor. By bringing them into close contact, it was possible to transport and develop non-magnetic toner.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the only force that holds the toner on the developing roller is the electrostatic adsorption force due to the toner's own charge, so the toner holding force is small, and the toner is not transferred to the photoreceptor, etc. When developing on a latent image carrier, uncharged toner or toner with a non-regular polarity is developed in the non-image area, and there is a significant amount of ground blur (a state in which toner adheres to the non-image area) on the latent image carrier. When used in an image forming device such as electrophotography, only toner of the correct polarity is transferred to the recording paper, so a large amount of toner is not transferred and is discarded unnecessarily, resulting in an uneconomical situation. In addition, an excessive amount of space is required for the waste toner container, which increases the size of the image forming apparatus.

In addition, because the toner retention force is weak, even if charged to the correct polarity, toner with a large amount of charge per unit mass of light will adhere to non-image areas due to image force etc. when it comes into contact with the latent image carrier in the development area. This was the cause of soil burrs remaining on the recording paper.

Therefore, the present invention is intended to solve these problems, and its purpose is to reduce soil strength blurring and density unevenness, and to
The purpose of the present invention is to provide a developing device with a stable toner conveyance amount. Still another object is to provide a developing device that can reduce unnecessary waste toner. Still another object is to provide a developing device that has a simple structure and is applicable to small, low-cost image forming apparatuses. Still another object is to provide a developing device with high resolution and high image quality.

[Means for Solving the Problems] The developing device of the present invention is a developing device that develops a one-component magnetic toner onto a latent image carrier using a developing roller, in which the developing roller has a cylindrical thin film member and a cylindrical thin film member. It is characterized by having a drive roller that contacts at least a portion of the inner circumferential side surface, and having at least a magnetic field generating means inside the thin film member.

Further, the developing device of the present invention is characterized in that the thin film member is pressed against the latent image carrier.

Furthermore, the developing device of the present invention is characterized in that the thin film member has at least a magnetic field generating layer.

Furthermore, the developing device of the present invention is characterized in that the drive roller has at least a magnetic field generating means.

[Function] According to the above configuration of the present invention, by arranging the magnetic field generating means inside the thin film member, the holding force of the - component magnetic toner on the thin film member is increased, so that the magnetic field on the latent image carrier is increased. It is possible to reduce ground force blur and toner scattering due to adhesive force in non-image areas, and to stably form high-resolution images.

Further, according to the above structure of the present invention, the developing electric field can be emphasized by pressing the thin film member, which is the developing electrode, against the latent image carrier, and the gap between the latent image carrier and the thin film member is defined by the toner layer thickness. As a result, the developing electric field is stabilized, and since the developer is held by magnetic force, it is possible to stably form high-temperature, high-resolution images with little ground force blur even in contact development.

Further, according to the above configuration of the present invention, the thin magnetic field generating layer is magnetized at a minute pitch to form a uniform and thin toner layer (or a thin magnetic brush layer at a minute pitch) on the developing roller. It reduces density unevenness caused by variations in toner layer thickness, holds the toner on the developing roller using magnetic force, reduces ground blur, and enables development with high resolution and high print quality. can. Furthermore, by reducing soil blurring and reducing unnecessary waste toner, it is possible to make the image forming apparatus smaller and lower in cost and maintenance, and it is also possible to reduce toner consumption and running costs.

Further, according to the above configuration of the present invention, since the drive roller has the magnetic field generating means, the magnetic toner is held and conveyed by leakage magnetic flux from the magnetic field generating means, and density unevenness due to variations in the toner layer thickness is reduced. , the toner is triboelectrified by oscillating the toner using leakage magnetic flux, and the toner is held on the developing roller by magnetic force to reduce ground force blur, enabling high-temperature, high-resolution, and high-print quality development. can.

Hereinafter, the details of the present invention will be shown by examples.

[Example 1] FIG. 1 is a cross-sectional schematic diagram of an image forming apparatus using a developing device of the present invention, in which a latent image carrier 1 has a conductive support section 2.
A photosensitive layer 3 having organic or inorganic photoconductivity is coated on top of the photosensitive layer 3, and after the photosensitive layer 3 is charged using a charger 4 such as a corona charger or a charging roller, it is charged with a laser, LED, etc. The light emitted from the light source 5 is selectively irradiated onto the photosensitive layer 3 according to the image through the imaging optical system 6 to obtain a potential contrast and form an electrostatic latent image. On the other hand, the developing device 7 conveys and develops the magnetic toner 8.
The developing roller 9 is rotationally driven and has a friction member on its outer periphery, a cylindrical thin film member 11 that is sheathed with an extra length left on the outer periphery of the drive roller 10, and a magnetic field generated within the thin film member 11. The means 12 holds the magnetic toner 8 on the thin film member 11 by the leakage magnetic flux of the magnetic field generating means 12 or the electrostatic force caused by the charging of the toner itself. A thin layer of toner 8 is conveyed by rotating the developing roller 9 while regulating the amount to an appropriate amount with an elastic blade 13, and the toner 8 is conveyed to the developing section where the thin film member 11 is pressed against the latent image carrier 1. Then, a developing electric field is formed by the potential contrast of the latent image carrier 1 and the developing bias applying means 14, and the toner 8 charged according to the developing electric field is
is attached to the latent image carrier 1, the electrostatic latent image is visualized, and then the toner image is transferred onto the recording paper 16 using a transfer device 15 such as a corona transfer device or a transfer roller, and then the toner image is transferred to the recording paper 16 using heat or pressure. The toner is fixed on the recording paper using the toner to obtain a desired image on the recording paper. In the developing device shown in FIG. 1, the magnetic field generating means 12 included in the thin film member 11 holds the supplied toner 8 on the thin film member 11 by magnetic force, and prevents soil blur due to the adhesive force of uncharged toner. This is intended to reduce toner scattering and toner blurring in which toner with a large amount of charge per unit mass adheres to non-image areas due to mirror image force or the like. Furthermore, the developing electric field can be emphasized by pressing the thin film member, which is the developing electrode, against the latent image carrier, and since the gap between the latent image carrier and the thin film member is defined by the toner layer thickness, the developing electric field is stabilized, and the toner Because it is held by magnetic force, it is possible to stably form high-density, high-resolution images with no background blur even during contact development.

Using a developing device as shown in FIG.
PI] line image, character image, and solid image 1
When continuously formed over 0,000 sheets, 600 [D
PI] line image is stably formed without line thickening, there is no trailing or blurring at the edge of the image, and the OD value is 1.
It is possible to stably form a solid image with a high density of 4 or higher, and there is no ground force blur in the image transferred onto the recording paper, and there is also no ground force blur on the latent image carrier, significantly reducing the amount of waste toner. We were able to reduce this.

FIG. 2 is a cross-sectional schematic diagram of an image forming apparatus using a developing device according to another embodiment of the present invention, in which members having substantially the same functions, functions, and names as those in FIG. 1 are given the same numbers and explained. omitted. The developing device 21 conveys and develops the magnetic toner 8, and the developing roller 22 that conveys the toner 8 is driven to rotate and has a friction member on the outer periphery of the driving roller 10 and an extra length on the outer periphery of the driving roller 10. It is composed of a cylindrical thin film member 23 that is externally covered with a cylindrical thin film member 23 and a magnetic field generating means 12 contained in the thin film member 23. A magnetic field generating layer 24 is disposed on the thin film member 23. The toner 8 is applied to the magnetic field generation layer 2
4, leakage magnetic flux from the magnetic field generating means 12, or electrostatic force due to the charging of the toner itself.
The developing roller 22 is rotated in a state in which the amount of toner 8 is regulated to be suitable for development by a thin spring-like elastic blade 13 made of non-magnetic or magnetic metal or resin. It is meant to be transported. The magnetic field generating means 12 holds the supplied toner 8 on the thin film member 23 by magnetic force, and causes ground force blur and toner scattering due to the adhesive force of uncharged toner, and toner with a large electric charge per unit mass, such as mirror image force. The purpose is to reduce soil blur that adheres to non-image areas. In addition, the magnetic field generation layer 24 disposed on the thin film member 23 holds the toner on the thin film member by its leakage magnetic flux, so that the toner holding force is insufficient due to the electrostatic adhesion force generated by the toner's own charging. This makes it possible to stabilize the amount of toner conveyed regardless of the consumption pattern of the toner on the thin film member that was consumed in the previous development, and in the development area, the adhesive force of uncharged toner and the mirror image force of toner with a large amount of charge are used. This prevents adhesion to the latent image carrier and reduces ground force blur. The developing electric field can be strengthened by pressing the thin film member, which is the developing electrode, against the latent image carrier, and since the distance between the latent image carrier and the thin film member is determined by the toner layer thickness, the developing electric field is stabilized, and the toner generates a magnetic field. Layer 24 and magnetic field generating means 1
Since it is held by the magnetic force of 2, it is possible to stably form a high-density, high-resolution image with no ground force blur even during contact development.

Using a developing device as shown in FIG.
When line images, character images, and solid images of [DPI] were continuously formed on 10,000 sheets, the result was 600 [DPI].
DPI] line images are stably formed without line thickening, the line pair image has the highest resolution, there is no trailing or blurring at the image edges, and it is a high-density solid image with an OD value of 1.4 or higher. was able to be stably formed, and there was no background blur in the image transferred onto the recording paper, and there was also no background blur on the latent image carrier, making it possible to significantly reduce the amount of waste toner.

FIG. 3 is a cross-sectional schematic diagram of an image forming apparatus using a developing device according to another embodiment of the present invention, in which members having substantially the same functions, functions, and names as those in FIG. 2 are given the same numbers and explained. omitted. The developing device 31 conveys and develops the magnetic toner 8, and the developing roller 32 that conveys the toner 8 is rotationally driven. A cylindrical thin film member 23 and a thin film member 23 that are packaged with extra length left in the
A magnetic field generating layer 24 is provided on the thin film member 23. The toner 8 is held on the thin film member 23 by leakage magnetic flux from the outer periphery of the magnetic field generation layer 24, leakage magnetic flux from the drive roller 30 having a magnetic field generation means, or electrostatic force caused by charging the toner itself. The thin layer of toner 8 is conveyed by rotating the developing roller 32 in a state where the elastic blade 13 in the shape of a thin plate spring is regulated to a degree suitable for development. The magnetic field generating means 12 holds the supplied toner 8 on the thin film member 23 by magnetic force, and causes ground force blur and toner scattering due to the adhesive force of uncharged toner, and toner with a large electric charge per unit mass, such as mirror image force. The purpose is to reduce soil blur that adheres to non-image areas.

The magnetic field generating layer 24 disposed on the thin film member 23 retains the toner on the thin film member by its leakage magnetic flux.
The toner retention force, which is not sufficient due to the electrostatic adhesion force generated by the toner's own charge, is strengthened, and the amount of toner conveyed can be stabilized regardless of the toner consumption pattern on the thin film member that was consumed in the previous development. The purpose of this invention is to prevent the adhesion of uncharged toner to the latent image carrier due to the adhesive force of uncharged toner and the mirror image force of toner with a large amount of charge, thereby reducing the blurring caused by ground force.

The driving roller 3o having a magnetic field generating means holds the toner on the thin film member 23 by leakage magnetic flux to stabilize the amount of toner conveyed, and uses the elastic blade 13 to hold the toner on the thin film member 23.
The toner 8, which is pressed against the toner 8, is swung by magnetic force to impart frictional electrification. In addition, the developing electric field can be emphasized by pressing the thin film member that is the developing electrode against the latent image carrier, and since the distance between the latent image carrier and the thin film member is determined by the toner layer thickness, the developing electric field is stabilized and the toner is Magnetic field generation layer 2
4 and a drive roller 3 having a magnetic field generating means, the image is held by the magnetic force of 3 degrees, so that it is possible to stably form a high-density, high-resolution image without any ground force blur even in contact development.

Using a developing device as shown in FIG.
PI] line image, character image, and solid image 1
When continuously formed over 0,000 sheets, 600 [D
PI] line images are stably formed without line thickening, the line pair image has the highest resolution, there is no trailing or ground blur at the image edges, and it is a high-density solid image with an OD value of 1.4 or more. was able to be stably formed, and there was no background blur in the image transferred onto the recording paper, and there was also no background blur on the latent image carrier, making it possible to significantly reduce the amount of waste toner.

In FIGS. 1 to 3, a drive roller 10 or a drive roller 30 having a magnetic field generating means has a friction portion made of natural rubber, silicone rubber, urethane rubber, butadiene rubber, chloroprene rubber, neoprene rubber, NBR, etc. on the outer periphery. The rotary drive force is transmitted by pressing the thin film member against the drive roller. Further, the magnetization direction of the magnetic field generating means 12.30 may be any direction such as not only the normal direction of the photoreceptor or the drive roller but also the tangential direction or the axial direction, and the magnetization pattern may also be in the form of a line, a grid, a spiral, etc. The magnetic field generating means is not limited to permanent magnets, but may be any device that generates a magnetic field such as an electromagnet. Further, the thin film member can be a metal thin film such as phosphor bronze, stainless steel, or nickel, or a resin thin film material such as nylon, polyimide, or polyethylene terephthalate.The thickness of the thin film member varies depending on the material, but the latent image carrier In order to obtain sufficient pressure contact with
] is preferable. Furthermore, the magnetic field generation layer 24 can be made of a known magnetic recording material or magnet material, and more specifically, Fe, Ni, Co, etc.
, Mn, for example, γ-Fe2O3, Ba-Fe,
Ni-Co, Co-Cr, Mn-Al, etc. can be used.
The film thickness is reduced to 100 [μm] or less, preferably around 10 [μm], and the minimum magnetization reversal pitch is made to be 100 [μm] or less to make the toner a uniformly thin layer. At the same time, the toner is transported on the developing roller by magnetic brush formation. It is possible to suppress variations in the amount to a minute pitch and reduce density unevenness. Further, as the toner used in the present invention, all toners known as -component magnetic toners can be used, and the composition of the toner may be resin-based toner or wax-based toner. It is made by adding magnetic powder, coloring agents, external additives, and other additives to the powder, and is created by pulverization or polymerization methods.

In addition, in FIGS. 1 to 3, the present invention is not limited to the configurations shown in the figures, and although the arrows indicate the rotation directions of the respective members, the present invention is not limited to the configurations shown in the figures. The developing method can be used regardless of whether it is regular development or reversal development.

FIG. 4(a) is a diagram showing the layer structure of the thin film member of the developing roller in the embodiment of the present invention, in which a magnetic field generating layer 42 is provided on the thin film member 41, and the magnetic field generating layer 42 is arranged at a magnetization reversal pitch. By magnetizing in the horizontal direction so that
3, a fine toner chain is formed and a thin and stable toner layer is obtained. In addition, by forming the thin film member 41 with a resin thin film in which a conductive material such as a conductive SE metal thin film or carbon black is dispersed in an elastic resin, a developing bias voltage can be applied to the thin film member 41 to produce a developing electrode effect. can be improved to obtain high-resolution images. Furthermore, the fourth
As shown in Figure (b), by magnetizing the magnetic field generation layer 44 in the perpendicular direction, the magnetization reversal pitch is adjusted to
It is possible to increase the density to around 0 [μm], and it is also possible to uniformly form a single thin layer of toner, and because a strong magnetic field can be obtained on the surface of the magnetic field generation layer, magnetic toner 4
By reducing the magnetic powder content in No. 3, it is possible to facilitate toner production and improve fixing properties. Furthermore, the magnetic field generation layer 44 can be used in various magnetized states such as line magnetization, grid magnetization, and spiral magnetization. Alternatively, a magnetic field generating layer in the form of a film, which has been magnetized in advance, may be appropriately disposed on the developing roller by means such as adhesion.The arrow in the figure indicates the direction of magnetization.

Although the embodiments have been described above, the present invention can be applied not only to the above embodiments but also to a wide range of developing devices such as electrophotography.
It is especially effective when applied to printers, copiers, facsimiles, and displays.

[Effects of the Invention] As described above, according to the present invention, by arranging the magnetic field generating means inside the cylindrical thin film member, the holding force of the - component magnetic toner on the thin film member is increased. It is possible to reduce ground blurring and toner scattering due to adhesive force to non-image areas on the latent image carrier, and it is possible to stably form high-resolution images.

In addition, by pressing the thin film member that is the developing electrode against the latent image carrier, the developing electric field is emphasized, and since the developing gap is defined by the toner layer thickness, the electric field is stabilized, making it possible to stably produce high-temperature, high-resolution images. Can be formed. Furthermore, by strengthening the toner retention force using leakage magnetic flux from the magnetic field generating means, it is possible to prevent uncharged toner or highly charged toner from adhering to the latent image carrier due to mirror image force even during contact development. It is possible to form images with less turbulence.

Furthermore, by arranging a magnetic field generation layer on the thin film member,
Because the toner is transported directly on the surface of the magnetic field generation layer, the amount of transport is stable, and by making the minimum magnetization reversal interval extremely narrow, a minute toner chain is formed, resulting in a thin and stable toner layer, which reduces the toner layer thickness. Reduces density unevenness caused by fluctuations,
By holding the toner on the developing roller by magnetic force, it is possible to reduce ground force blur and perform development with high resolution and high print quality. Furthermore, by reducing soil blurring and reducing unnecessary waste toner, it is possible to make the image forming apparatus smaller and lower in cost and maintenance, and it is also possible to reduce toner consumption and running costs.

Furthermore, by having a magnetic field generating means in the drive roller, the magnetic toner is held and conveyed by leakage magnetic flux from the magnetic field generating means, reducing density unevenness due to variations in toner layer thickness.
The toner is oscillated by leaked magnetic flux to impart a sufficient amount of triboelectrification, and the toner is held on the developing roller by magnetic force to reduce ground blurring and develop with high density, high resolution, and high printing quality. I can do it.

Therefore, the developing device of the present invention has an excellent effect in that it can provide a developing device that can obtain high-density and high-resolution images with few image defects such as ground blur and trailing in the -component magnetic development method. It is something.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional schematic view of an embodiment of the developing device of the present invention, FIG. 2 is a cross-sectional schematic diagram of another embodiment of the developing device of the present invention, and FIG. 3 is a cross-sectional schematic diagram of another embodiment of the developing device of the present invention. FIG. 4 is a schematic cross-sectional view of another embodiment of the present invention, and FIG. 4 is a diagram showing the layer structure of the thin film member of the developing roller in the embodiment of the present invention. Latent image carrier 8, 43... Toner 9, 22.
32 Developing roller 11, 23. 41 24, 42. 44 Drive Roller Thin Film Member Magnetic Field Generating Means Elastic Blade Magnetic Field Generating Layer Drive Roller Having Magnetic Field Generating Means Applicant Seiko Epson Co., Ltd. Agent Patent Attorney Kizobe Suzuki (1st name) Figure 1

Claims (4)

[Claims] (1) In a developing device that develops a one-component magnetic toner onto a latent image carrier using a developing roller, the developing roller is driven to contact at least a portion of a cylindrical thin film member and an inner peripheral side surface of the cylindrical thin film member. A developing device comprising a roller and at least magnetic field generating means included in the thin film member. (2) The developing device according to claim 1, wherein the thin film member is pressed against the latent image carrier. (3) The developing device according to claim 1 or 2, wherein the thin film member has at least a magnetic field generating layer. (4) The developing device according to claim 1, wherein the drive roller has at least magnetic field generating means.