JPH0451274A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of the flow of an image caused by a developing history occurring on a latent image carrier, to stabilize the carrying quantity of toner, and to reduce density irregularities and base fogging by providing a drum-like thin film member as a developing roller, a driving roller, and a developer supplying/peeling off member peeling off a one component developer which is not used in the last development. CONSTITUTION:The developer supplying/peeling off member 12 has a fur brush for electrifying the toner to a desired polarity according to a triboelectrifying system, and the fur brush is formed by planting fiber on a conductive supporting body freely rotated. A potential difference is given with respect to the developing roller 9 by a voltage applying means 17. The toner 8 electrified by triboelectrification, contact electrification, the injection of a charge, etc., to carry out sufficient development, sticks to the developing roller of the toner having a desired polarity according to an electric field formed by the voltage applying means 17 between the developer supplying/peeling off member and the developing roller, so that base fogging caused by the sticking of the toner having the reverse polarity and unelectrified toner on the latent image carrier can be reduced. On the other hand, the developer supplying/ peeling off member 12 tentatively peels off all of the toner which is not used for the development, so that the solidifying of the toner on the developing roller and the occurrence of the flaw of the image of the density irregularities, etc., caused by the developing history are suppressed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a developing device that uses a one-component developer.

[Prior Art] As disclosed in Japanese Patent Application Laid-Open No. 63-226676, a conventional developing device has an elastic blade pressed against a cylindrical thin film member sleeve having an excess circumferential length with respect to a drive roller. The toner that has reached the pressure contact area is frictionally charged by the blade, and the electrostatic force causes the toner to adhere to the thin layer member, making it possible to transport and develop the nonmagnetic toner.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, density unevenness occurs due to the toner not being supplied in time to the part of the toner consumption pattern used in the previous development on the developing roller.
A problem has arisen in which image defects occur due to the development history, such as flow rate unevenness, which is caused by a significant difference in the amount of charge between the toner newly attached to the area where the toner has been consumed and the toner that has remained attached since the previous time. Ta.

In addition, if the only forces that hold the toner on the developing roller are electrostatic mirror image force and adhesive force, the holding force is small, so when toner is developed on a latent image carrier such as a photoreceptor, uncharged toner and regular When used in an image forming device such as electrophotography, a toner with a polarity other than that of Since only toner of the correct polarity is transferred to the recording paper, a large amount of toner is not transferred and is discarded unnecessarily, which is not only uneconomical but also requires an excessive amount of space in the waste toner container. was made larger. 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.

The present invention is intended to solve these problems, and its purpose is to prevent the occurrence of image defects caused by the development history that occurs on the latent image carrier, and to stabilize the amount of toner conveyed. The object of the present invention is to provide a developing device with less unevenness in density and less blurring. 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 developer 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 has a cantering roller that contacts at least a portion of the inner circumferential side surface, and supplies a one-component developer to the developing roller and also supplies a developer for peeling off the one-component developer that was not used in the previous development. It is characterized by having a peeling 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 developing roller has a magnetic field generating means included in the thin film member.

[Function] According to the above configuration of the present invention, a developer supplying and peeling member is provided for supplying the monocomponent toner to the developing roller and peeling off the monocomponent toner that was not used in the previous development. As a result, toner on the thin film member that was not used in the previous development can be peeled off and toner with sufficient charge and desired polarity can be stably supplied onto the thin film member to perform new development. It is possible to reduce the occurrence of image defects such as ground blur due to toner of opposite polarity adhering to the body and density unevenness due to development history, and it is possible to stably form high-resolution images regardless of development history.

Further, according to the above structure of the present invention, the developing electric field can be strengthened by pressing the thin film member serving as 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 high-temperature, high-resolution images can be stably formed.

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 temperature unevenness caused by variations in toner layer thickness, holds the toner on the developing roller by magnetic force, reduces ground blur, and enables 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, according to the above configuration of the present invention, by arranging the magnetic field generating means inside the thin film member, the retention force of the - component magnetic toner on the thin layer member is increased, so that the magnetic field generated on the latent image carrier is It is possible to reduce ground force blur and toner scattering due to adhesive force in non-image areas, and to stably form high-quality images.

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

[Example] 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 toner 8, and the developing roller 9 that conveys the toner 8 is driven to rotate, leaving a drive roller 10 having a friction member on the outer periphery and a surplus member on the outer periphery of the driving roller 10. The toner 8 is composed of a cylindrical thin film member 11 that is externally covered with a cylindrical thin film member 11, and the toner 8 that has been charge-injected or tribo-electrified by the developer supply and peeling member 12 is applied to the developing roller according to the electric field formed by the voltage applying means 17. The toner moves upward and adheres, is held on the thin film member 11 by the electrostatic force caused by the toner's own charge, and is regulated in an appropriate amount by an elastic blade 13 in the shape of a thin plate spring made of non-magnetic or magnetic metal or resin. The developing roller 9 is rotated to convey a thin layer of toner 8. When the toner 8 is conveyed to the developing section where the thin film member 11 is pressed against the latent image carrier 1, the potential contrast and the potential contrast of the latent image carrier 1 are changed. A developing electric field is formed by the developing bias applying means 14, the toner 8 charged according to the developing electric field adheres to the latent image carrier 1, and the electrostatic latent image is visualized. A toner image is transferred onto a recording paper 16 using a transfer device 15, and the toner is fixed onto the recording paper using heat or pressure to obtain a desired image on the recording paper. The developer 8 that has not been developed on the latent image carrier in the development gap is collected into a hopper as the developing roller rotates, and when the developer 8 is conveyed to a position where the developing roller 9 faces the developer supplying and separating member 12, the developer is removed. The toner 8 is peeled off from the thin film member 12 by the mechanical, magnetic, or electrical force of the supply and peeling member 12, and the toner 8 that has been charged or triboelectrically charged is newly supplied.

In the developing device shown in FIG. 1, a developer supplying and peeling member 12 disposed opposite the developing roller 9 is a rotatable conductive fur brush that charges the toner to a desired polarity according to a triboelectric charging series. The toner 8 is flocked on a support and a potential difference is created between it and the developing roller 9 by the voltage applying means 17, and the toner 8 that has been sufficiently charged for development by frictional charging, contact charging, charge injection, etc. Since only toner having a desired polarity adheres to the developing roller according to the developer supply formed by the applying means 17 and the electric field between the peeling member and the developing roller, toner of opposite polarity or uncharged toner is not deposited on the latent image carrier. It can reduce soil strain due to adhesion. Further, the developer supply and peeling member 12 rubs the toner 8 collected in the hopper without being developed on the latent image carrier in the development gap with a fur brush at a position facing the development roller, and applies mechanical force. , the toner is peeled off from the thin film member 11 by electric or magnetic force, etc., and in order to remove all the toner that has not been used for development from the developing roller, it prevents toner from sticking to the developing roller. The occurrence of image defects such as density unevenness due to development history can be suppressed.

Using a developing device as shown in FIG.
PI] line image, character image, and solid image 1
When 0,000 sheets were continuously formed, 600 [DP
Line images are stably formed without line thickening, and there are no image defects such as uneven density due to development history, trailing at the edges of the image, or blurring, and the line image has a high OD value of 1.4 or more. It is possible to stably form solid images at high temperatures.
Not only was there no background blur in the image transferred onto the recording paper, but there was also no background blur on the latent image carrier, making it possible to significantly reduce waste toner.

FIG. 2 is a cross-sectional schematic diagram of the developer supplying and peeling member in the embodiment of the present invention. When the developing roller does not have a member that generates a magnetic field, a fur brush roller is used as the developer supplying and peeling member 12. In addition, a magnetic brush is formed by attaching magnetic particles 24 by magnetic force to a mag roller 23 which is composed of a conductive non-magnetic rotatable sleeve 21 and a rotatable magnetic field generating member 22 contained therein.
A structure may be adopted in which the toner 8 is charged and supplied to a developing roller (not shown) and the toner remaining after development is peeled off by utilizing the frictional action of a magnetic brush.Also, even in a case where the developing roller has a magnetic field generating means, If a magnetic fiber brush (not shown) consisting of a conductive non-magnetic rotatable sleeve in which soft magnetic fibers are flocked and a magnetic field generating means included therein is used as a developer supply and stripping member, the magnetic brush can be used. Using the abrasion effect, toner can be charged, supplied to a developing roller, and the toner remaining after development can be peeled off.

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. 1 are given the same numbers and explained. omitted. The developing device 36 conveys and develops magnetic toner 37, and the developing roller 33 that conveys the toner 37 is driven by a drive roller 30 that is rotationally driven and has a friction member on the outer periphery.
A cylindrical thin film member 31 is provided on the outer periphery of the drive roller 30 with an extra length left, and a magnetic field generating layer 32 is disposed on the thin film member 31.
4 is placed in a pressed state against the thin film member 31. The developer supplying and peeling member 34 is a rotatable roller made of foamed, elastic and conductive material such as polyurethane, and has a potential difference with the developing roller by the voltage applying means 17. Frictional charging on 34,
The one-component magnetic toner 37 that has been charged by contact charging, charge injection, etc. is transferred to the developing roller 33 in accordance with the electric field between the developing roller 33 formed by the voltage applying means 17 and the developer supplying and peeling member 34, so that only toner of a desired polarity is transferred to the developing roller 33. This is applied to the latent image carrier to reduce toner blur due to adhesion of toner of opposite polarity or uncharged toner onto the latent image carrier, and also toner that has been collected while being held on the thin film member without being developed. By peeling off the toner from the developing roller using mechanical, magnetic, electrical force, etc., it suppresses the occurrence of image defects such as uneven hot water temperature caused by the development history, and prevents the toner from sticking on the development roller. This makes it possible to form images stably. The magnetic field generation layer 32 disposed on the thin film member 31 holds the supplied one-component magnetic toner 37 on the thin film member 31 by magnetic force, and the toner itself is electrostatically attracted onto the thin film member due to its own charging. This stabilizes the amount of conveyance which would otherwise be unstable with force alone, and in the development area, reduces the ground force blurring on the latent image carrier due to the adhesive force of the toner, making it possible to form a stable image.

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, there are no image defects such as temperature unevenness caused by the development history, there is no trailing or blurring at the edges of the image, and the OD value is 1.
It is possible to stably form a solid image at a high temperature 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.

FIG. 4 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 46 conveys and develops the one-component magnetic toner 45, and includes the developing roller 4 that conveys the toner 45.
3 is constituted by a drive roller 40 that is rotationally driven and has a friction member on the outer periphery, a cylindrical thin film member 41 that is sheathed with an extra length left on the outer periphery of the drive roller 40, and a magnetic field generating means 42 that is included in the thin film member 41. , a developer supplying and peeling member 44 is disposed opposite the developing roller 43 . The developer supply and peeling member 44 is a rotatable magnetic roller whose surface is magnetized with multiple poles, and the voltage application means 17
The one-component magnetic toner 45 which has a potential difference with the developing roller 43 and has been charged by frictional charging, contact charging, charge injection, etc. by the developer supply and peeling member 44 is transferred to the developing roller formed by the voltage applying means 17. 43 and developer supply and! 1Ijl [This system allows only the toner of a desired polarity to adhere to the developing roller 43 according to the electric field between the members 44, which can reduce ground blur due to adhesion of toner of opposite polarity or uncharged toner onto the latent image carrier, and further, Mechanically, the toner collected without being developed and retained on the thin film member is rubbed on the developer supply and peeling member with a magnetic brush made of one-component magnetic toner 45.
It can be peeled off from the developing roller by magnetic or electrical force, and it suppresses the occurrence of image defects such as temperature unevenness caused by the development history and the sticking of toner on the development roller, making it stable regardless of the development history. This makes it possible to form images using The magnetic field generating means 42 included in the thin film member 41 holds the supplied one-component magnetic toner 45 on the thin film member 41 by magnetic force, and only generates electrostatic attraction force onto the thin film member due to the charging of the toner itself. By using magnetic force to enhance the toner holding power that is not sufficient with the above methods, it is possible to stably form high-resolution, high-density images by reducing ground force blur and toner scattering on the latent image carrier due to the adhesive force of the toner. is possible.

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, there are no image defects such as temperature unevenness caused by the development history, there is no trailing or blurring at the edges 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 to 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.

The magnetization direction of the magnetic field generating means 42 may be not only the normal direction of the photoreceptor or the drive roller but also any direction such as the tangential direction or the axial direction, and the magnetization pattern may also be linear, lattice, spiral, etc.
The magnetic field generating means is not limited to a permanent magnet, but may be any device that generates a magnetic field such as an electromagnet.

In FIGS. 1 to 4, a fur brush roller, a foamed conductive elastic roller, a magnetic roller, etc. are used as the developer supply and female members, but the toner is charged to a desired polarity and supplied to the development roller, and the toner is not developed. It may be in any form, such as a blade shape, as long as it removes all the toner remaining on the developing roller without removing the toner.
The drive roller has a friction part on its outer periphery made of natural rubber, silicone rubber, urethane rubber, butadiene rubber, chloroprene rubber, neoprene rubber, NBR, etc., and transmits rotational driving force by pressing a thin film member against the drive roller. It is something to do. Furthermore, thin film members include metal thin films such as phosphor bronze, stainless steel, nickel, etc., nylon, polyimide, etc.
A resin thin film material such as polyethylene terephthalate can be used, and the thickness of the thin film member varies depending on the material, but in order to obtain sufficient pressure contact with the latent image carrier, it is approximately 10 to 5°0 [μm]. Further, the magnetic field generation layer 32 can be made of a material known as a magnetic recording material or a magnet material, and more specifically, Fe, Ni,
A magnetic material containing at least one element among Co and Mn, such as γ-Fe2O3, Ba-F
e, Ni-Co, Co-Cr, Mn-Al, etc. can be used, and the film thickness is preferably 100 [μm] or less, and preferably 10 [μm].
The film is made thin around m1, and the minimum magnetization reversal pitch is set to 100 [μ
m] or less, the toner can be uniformly made into a thin layer, and at the same time, fluctuations in the amount of toner conveyed on the developing roller due to magnetic brush formation can be suppressed to a minute pitch, thereby reducing temperature unevenness. Further, as the toner used in the present invention, all toners known as -component toners can be used.
The composition of the toner is either resin-based toner or wax-based toner.As is well known, the composition of the toner is a mixture of resin, magnetic powder, colorants, external additives, and other additives, and is processed by pulverization, polymerization, etc. Created.

In addition, in FIGS. 1 to 4, the present invention is not limited only to the configurations shown in the figures, and although the arrows indicate the rotation direction of each member, the present invention is not limited to the following. The developing method can be used regardless of whether it is regular development or reversal development.

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 developer supplying and peeling member facing the developing roller and having a potential difference between it and the developing roller by a voltage applying means, Frictional charging, contact charging, charge injection, etc. can impart a sufficient amount of charge to the toner for development, and only toner with the desired charge polarity can be supplied to the developing roller according to the electric field, so that the latent image carrier is It is possible to prevent blurring caused by polar toner adhesion, and furthermore, it uses mechanical, magnetic, electrical force, etc. to peel off the toner that is collected while remaining on the developing roller without being developed.
It is possible to prevent image defects such as temperature unevenness caused by the development history and toner from sticking to the developing roller, and it is possible to form a stable image regardless of the development history.

In addition, 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 stable and the temperature is high. Moreover, high-resolution images can be stably formed.

Furthermore, by magnetizing the thin magnetic field generation layer at a minute pitch, it is possible to form a uniform and thin toner layer (or a thin layer of magnetic brush at a minute pitch) on the developing roller, and the thickness of the toner layer can be reduced. Temperature unevenness caused by fluctuations can be reduced, toner is held on the developing roller by magnetic force, and ground blur can be reduced, and development can be performed 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 arranging the magnetic field generating means inside the thin film member, the retention force of the - component magnetic toner on the thin film member is increased, so that uncharged toner adheres to the latent image carrier due to its adhesive force, etc. This enables stable image formation by reducing ground blur and toner scattering in non-image areas.

Therefore, in the -component development method, the developing device of the present invention has the following features:
This has the excellent effect of providing a developing device that can produce high-temperature, high-resolution images with few temperature irregularities caused by development history and image defects such as trailing.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional schematic diagram of an embodiment of the developing device of the present invention, FIG. 2 is a cross-sectional schematic diagram of the developer supply and stripping member in the embodiment of the present invention, and FIG. 3 is a schematic cross-sectional diagram of the developing device of the present invention. FIG. 4 is a schematic cross-sectional view of another embodiment of the developing device, and FIG. 4 is a schematic cross-sectional diagram of another embodiment of the developing device of the present invention. 8, 37. 45 9, 33. 43 10, 30. 40 11, 31. 41 12, 34. 44 Toner development roller drive roller Thin film member Developer supply and peeling member Elastic blade Developing bias application means Voltage application means Magnetic particle magnetic field generation layer Magnetic field generation means Above Applicant Seiko Epson Corporation Agent Patent attorney Kizobe Suzuki (Case 1) Figure 3: Magnetic particle toner

Claims (4)

[Claims] (1) In a developing device that develops a one-component developer onto a latent image carrier using a developing roller, a drive in which the developing roller contacts at least a portion of a cylindrical thin film member and an inner peripheral side surface of the cylindrical thin film member. The method is characterized by having a roller, and a developer supplying and peeling member for supplying the one-component developer to the developing roller and peeling off the one-component developer that was not used in the previous development. Developing device. (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 developing roller has a magnetic field generating means included in a thin film member.