JPH03166568A - Developing device - Google Patents

Abstract

PURPOSE:To form a distinct image by making a fiber which protrudes at right angle from the surface of a toner supply means fully capture toner with magnetic field generated by a magnetic generation means and stably supplying the toner to a developing roller through the fiber. CONSTITUTION:The magnetic field is formed in a developing device 10 by a magnetic field generation means 16D, and the toner replenished to the develop ing device 10 is captured by the fiber 15 made of magnetic material of a toner supply means 12 with the aid of gravity and the magnetic field in the device 10. Since the fiber 15 which fully captures and holds the toner comes in contact with the developing roller 11 by rotating the toner supply means 12, the toner is fully supplied to the developing roller 1. According to the magnetic field formed in the developing device 10, the fiber 15 comes in contact with the developing roller 11 while it freely moves by the magnetic field, so that the toner is extremely uniformized and supplied to the developing roller 11. Thus, the distinct toner image is always formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a developing device, and particularly to a developing device used in an image forming apparatus such as a copying machine.

[Prior Art] An image forming apparatus such as a copying machine has a method of supplying toner to form a visualized toner image on a latent image formed on a photoreceptor by exposure corresponding to an image on a document. A developing device is provided.

This type of developing device disclosed in Japanese Patent Application Laid-Open No. 61-105573 has a cylindrical sleeve and a developing roll arranged in the housing facing the opening of the housing, and a photoreceptor is arranged close to and facing the developing roll. A magnet is housed within the cylindrical sleeve.

As a developer, a magnetic carrier and two
A two-part developer consisting of 7 to 7 weight percent of negatively charged toner is used, and this developer is fed into a cylindrical sleeve.

DC power is applied between the developing roller and the cylindrical sleeve,
The negatively charged toner in the developer is electrostatically attracted to the developing roller, the developing roller is rotated at the same speed as the circumferential speed of the photoreceptor, and the cylindrical sleeve is rotated at two to three times the speed of the developing roller. It is rotated, and the toner is brought into sliding contact with the latent image on the photoconductor to perform development. In this developing device, since a two-part developer is used, a magnet must be provided for holding the carrier in the cylindrical sleeve, which limits the degree of freedom in terms of illumination. In addition, the carrier tends to scatter, and the carrier adheres to the developing roller, damaging the toner thickness forming means provided on the developing roller, and in some cases, the carrier adhering to the roller may be developed and cause background stains. .

To solve these problems, developing devices that use a single-component developer consisting only of toner have come into use. Furthermore, in a developing device using a certain amount of developer disclosed in Japanese Patent Application Laid-Open No. 62-95558, a toner supply roller to which toner is supplied from a toner hopper is made of a conductive elastic material such as polyurethane. ．． Different voltages are applied to the developing roller, which has a rubber magnetic layer around the core material, and the toner supply roller, depending on the charging polarity of the toner used. In this developing device, the toner supplied to the toner replenishment roller is charged by friction with the surface of the developing roller, is electrostatically attracted to the developing roller, and is transported to the developing area where development is performed. In a developing device using a one-component developer disclosed in Japanese Patent Publication No. 63-50706, toner is directly supplied from a hopper to a developing roller, and a cylindrical magnet that rotates independently is arranged inside the developing roller. ing. A magnetic fiber made of stainless steel, for example, is attached to the peripheral surface of the developing roller.

In the developing device according to this disclosure, the magnetic fiber that conveys the toner is moved by the rotation of the cylindrical magnet, and the toner that adheres to the latent image forms a uniform toner image.

[Problems to be Solved by the Invention] As mentioned above, carrier scattering in a developing device using a two-command developer, damage to the toner thickness forming means by the carrier, background stains due to carrier development, or problems due to device design. The problem of limited degrees of freedom is solved by using a one-shot developer.

However, among the developing devices that use a developer, the one disclosed in Japanese Patent Application Laid-Open No. 62-95558 found that the toner is not supplied from the toner replenishing roller to the developing roller as a result of actual measurements by the inventors. However, it has been confirmed that the toner supply is unstable because it often depends on the mechanical characteristics between the replenishing roller and the developing roller rather than the set applied voltage between them. Furthermore, in the developing device disclosed in Japanese Patent Publication No. 63-50706, the toner is directly supplied from the hopper to the developing roller, so the toner is not sufficiently charged and the toner is not sufficiently supplied to the latent image. The object of the present invention is to stably supply toner at each stage, stably supply the necessary amount of toner to the latent image on the photoreceptor, and To provide a developing device that can always form clear toner images.

[Means for Solving the Problems] The above objective is to provide a toner supply means which is disposed in contact with the developing roller and has a fiber of a magnetic material protruding from the surface in a right angle direction, and supplies the toner to the developing roller. This is achieved by providing a magnetic field generating means that applies a magnetic field to this toner supply means. [Operation] A magnetic field is generated within the developing device by the magnetic field generating means, and the toner supplied to the developing device is captured by the magnetic fibers of the toner supplying means by gravity and the magnetic field within the developing device.

Then, as the toner supply means rotates, the fibers that have sufficiently captured and held toner come into contact with the developing roller, so that a sufficient amount of toner is supplied to the developing roller. Further, depending on the magnetic field exerted within the developing device, the fibers are moved freely by the magnetic field and come into contact with the developing roller, so that the toner is supplied to the developing roller in an extremely uniform manner.

In this way, the necessary amount of toner is stably supplied from the developing roller to the latent image on the photoreceptor, and a clear toner image is always formed.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of the overall configuration of each embodiment of the present invention, FIG. 2 is an explanatory diagram of the configuration of main parts of the first to fourth embodiments, and FIG. 3 is an explanatory diagram of the fifth embodiment. FIG. 4 is an explanatory diagram of the structure of the main part of the example, and FIG. 4 is an explanatory diagram of the structure of the main part of the sixth embodiment.
The figure is an explanatory diagram of the fiber structure in each embodiment.

In these figures, 1 is a photoreceptor, 2 is a charger, 3 is a transfer device, 4 is a cleaner, 5 is a cleaning blade, 6 is a static eliminator, 7 is a case, 10 is a developing device, 11 is a developing roller, 12 is a Toner supply port number 13 is agitator, number 4
15 is a thin layer blade, 15 is a magnetic fiber, 15a is a sleeve, and 16A to 16D are magnets. As shown in FIG. 1, a developing roller 11, a toner replenishing roller 12 serving as toner supplying means, an agitator 13, and a thin layer blade 14 are contained in a case 7 having an opening 7a.
The developing device 10 is configured by housing the developing device 10 .

That is, a developing roller 11 is disposed with its end protruding from the opening 7a so as to be rotatable around the shaft, and the developing roller 11 is in contact with the developing roller 11 so as to be rotatable around the shaft. - A replenishment roller l2 is provided. Further, a thin layer blade 14 is disposed close to and opposite to the developing roller 1, and an agitator 3 is rotatably disposed on the l end side of the bottom of the case 7.

A photoreceptor 1 is disposed close to and opposite to the developing roller 11 of the developing device IO, and is rotatable about an axis.
is grounded. A charger 2 is disposed above the photoreceptor 1 in close opposition to it, and a transfer device 3 is disposed below it in close opposition to it.

In the rotational direction θ■ of the photoreceptor 1, a cleaner 4 is adjacent to the transfer device 3 and faces the photoreceptor 1 closely.
is equipped with a brush 4a and a cleaning blade 5. A static eliminator 6 is arranged between the cleaner 4 and the charger 2 so as to be close to and face the photoreceptor 1.

Further, the developing roller 11 has a structure in which an insulating layer is formed on the surface of a conductive member, and a bias power source E1 is connected to this conductive member. The toner supply roller 12 includes a sleeve 15a made of a conductive non-magnetic material (for example, aluminum), to which one end of a fiber 15 of magnetic material is fixed, and the other end of the fiber 15 has a radius. It extends protrudingly in the direction.

This fiber 15 is made by mixing ferrite or magnetite into a packing material such as nylon or Teflon, and forming each fiber with a diameter of 0.005 mm to 0.1 mm, and an electrical resistance of 10.
A linear fiber with an elastic modulus of 0.2 to 21 N/m2 is formed into a linear fiber of ~10'Ω・Cm, and the end of this linear fiber is attached to a sleeve 15a with adhesive 8 in the radial direction as shown in FIG. The structure is such that the two protrude parallel to each other and are fixed.

Furthermore, as shown in FIG. 6, the above-mentioned linear fibers can be woven into a woven fabric and the free end side can be finished into a loop shape. In this case, 300 to 20 linear fibers are used.
It is preferable to collect about 00 lines and arrange them at equal intervals.

Further, for example, the fiber 15 can be constructed by fixing one end of a stainless steel magnetic wire to the sleeve 15a with a conductive adhesive and having the other end protrude parallel to each other in the radial direction. In this case, the entire fiber 15 attached to the sleeve 15a becomes electrically conductive.

Further, the bias power source E2 is applied to the sleeve 15a of the toner replenishing roller 12, and although FIG. 1 shows the case where the bias voltages gE and E2 are DC power sources, these power sources are AC Alternatively, it may be a power source in which direct current is superimposed on alternating current.

In the second embodiment, as shown in FIG. 2, a magnet 16D, which is a magnetic field generating means, is disposed on the outside of the case 7 of the developing device 110, facing the toner supply roller 2.

Next, the operation of the first embodiment having such a configuration will be explained.

The photoreceptor l, which has been completely transferred to the transfer paper, is indicated by the arrow θ in FIG.
, reach the cleaner 4 position while rotating in the direction, and move the brush 4.
Residual toner on the photoreceptor 1 is removed by the contact rotation of a and the sliding action of the cleaning blade 5. Then,
After residual static charge is discharged from the photoreceptor 1 by the static eliminator 6, the photoreceptor 1 is uniformly charged by the charger 2.

In this way, for the uniformly charged photoreceptor 1,
At the exposure position T shown in FIG. 1, light L modulated by the image of the original is irradiated, and a latent image corresponding to the image of the original is formed on the photoreceptor 1.

On the other hand, in FIG. 2, the toner replenished to the developing device 110 is moved inside the case 7 by the arrow θ. The magnet 16D of the toner replenishing roller 12 is stirred by the agitator l3 rotated in
and is captured by the fiber 15.

The toner captured by the fiber 15 is transferred to the developing roller king l by the toner replenishing roller 12 rotating in the direction of arrow θ3.
The toner replenishing roller 12 is conveyed to a position opposite to the developing roller 11 and rotates in the same direction as the developing roller 11 at a circumferential speed 2 to 3 times faster.
and the developing roller l1 are rotated in opposition to each other. As a result of this rotation, the toner is charged by friction with the surface of the developing roller l1, and is electrostatically attracted to the developing roller 11 by an electric field formed between the toner replenishing roller 12 and the developing roller 11 by the bias power source EtEx. Ru. The toner adsorbed to the developing roller 11 in this way is transferred to the thin layer blade 1.
4, the toner is frictionally charged between the developing roller 11 and the thin layer blade l4, and is deposited on the latent image at the developing position D facing the photoreceptor 1, forming a toner image on the photoreceptor 1. ．． In the first embodiment, a sufficient amount of toner is captured by the fiber 15, and the captured toner is charged by friction with the surface of the developer roller 11, and further frictionally charged between the developer roller 11 and the thin layer blade 14. Since development is performed in a sufficiently charged state, the required amount of toner is always stably supplied and a clear toner image is produced.

Also, the bias power supply E. ,E. By adjusting the toner captured by the fiber 15, the developing roller 1 and the photoreceptor 1
It is possible to set the optimum development conditions by controlling the supply amount. Further, cleaning can also be performed by peeling off the toner on the developing roller 11 and supplying new toner to the developing roller 11. By selecting the protruding length of the fiber 15 that is disposed to protrude from the sleeve 15a of the toner replenishing roller 12 in a direction perpendicular to the surface, an optimum amount of toner can be captured and the developing roller 1
1 under the optimum conditions, it is possible to set the optimum toner supply conditions. Magnetic fiber 15, sleeve 15
By making a and adhesive 8 conductive, sleeve 1
By easily applying the bias power source E to the fiber 15a, the voltage set by the bias power source E2 can be effectively applied directly to the toner without charging the fiber 15 itself. Since the sleeve 15a is made of a non-magnetic material, the magnetic field generated by the magnet 16D will not short-circuit at the sleeve 15a portion, and the magnetic field can effectively act on the fiber 15. In the second embodiment, as shown in FIG. 2, a magnet 16C for forming a magnetic field is disposed within the toner replenishing roller 12, and the sleeve 15a is rotatable about the shaft. In this second embodiment, the magnet 16G is connected to the toner replenishing roller 1.
By arranging the magnet 16C in the developing device 10, there is no need to provide a separate space for the magnet 16C, and the developing device 10 is made smaller.

The structure and effects of other parts of the second embodiment are the same as those of the first embodiment already described.

In the third embodiment, as shown in FIG.
is provided, and the sleeve 15a is rotatable around the shaft.

In this third embodiment, a magnetic dipole is formed in the fiber 15 of the sleeve 15a passing through the magnet 16B position, and the free end of the fiber 15 is moved by the magnetic field of the magnet 16B, and the toner captured in the fiber 15 is removed. By raising the fiber 15 in the protruding direction, the developing roller 1
1 and the toner, and stable toner supply to the developing roller 11 can be achieved.

The configuration and effects of other parts of the third embodiment are the same as those of the first embodiment already described.

In the fourth embodiment, as shown in FIG. 2, a magnet 16A is disposed within the developing roller 11, and the developing roller l1 is formed into a cylindrical shape and is rotatable about an axis.

In this fourth embodiment as well, a magnetic dipole is formed in the fiber 15 passing through the magnet 16A position, and the free end of the fiber 15 is moved by the magnetic field of the magnet 16A, and the toner captured by the fiber 15 is transferred to the fiber 15. By raising the toner in the protruding direction, it is possible to improve the contact between the developing roller l1 and the toner and to stably supply toner to the developing roller 11. Furthermore, in the fourth embodiment, the magnet l
By integrating 6A with the developing roller 11, the apparatus can be made more compact. The structure and effects of other parts of the fourth embodiment are as described in the first embodiment.
This is the same as the example. In the fifth embodiment, as shown in FIG. 3, a cylindrical magnet 18 is provided in the sleeve 15a so as to be rotatable independently, and different magnetic poles are successively adjacent to each other in the axial direction of the magnet 18. It is formed. In the fifth embodiment, in the same direction as the developing roller l1,
The magnet 18 rotates within the sleeve 15a of the toner replenishing roller 12, which rotates at three times the circumferential speed, at a rotation speed greater than the rotation speed of the sleeve 15a.

When the magnet 18 rotates, the toner captured by the fiber 15 is conveyed along the circumference of the fiber 15, and the toner is transferred to the magnet 8.
A magnetic dipole is formed in the fiber 15 by the rotation of
The free end of fiber 15 moves. In this case, the movement of the fiber l5 at any point depends on the gradient of the magnetic field created by the magnet 18. For example, by making the magnetic properties of each fiber 15 different, each fiber 15 can be caused to move differently in the circumferential direction and in the lateral direction.

By this movement of the fiber 15, the toner captured by the fiber 15 is transferred to the sleeve 15 of the toner supply roller 12.
It is possible to stably supply the fiber 15 with good contact to the developing roller 1l in a state in which the movement of the fiber 15 caused not only by the rotation of the magnet 18 but also by the rotation of the magnet 18 is superimposed.

The configuration and effects of the other parts of the fifth embodiment are the same as those of the already described first embodiment.

In the sixth embodiment, as shown in FIG. 4, in contrast to the fifth embodiment, the magnet 18A has a spiral magnetic pole in the axial direction. This magnet 18A is created with a desired magnetic field pitch by finely magnetizing the magnet in a spiral shape, or by cutting a ferrite formed in advance from a rubber or plastic sheet after magnetization, and attaching it in a spiral shape. Created by As such a ferrite material, for example, EPDM rubber mixed with 85 parts by weight of barium ferrite is used.

In this sixth embodiment, a magnetic dipole is formed in the fiber 15 by the rotation of the magnet 18A, and the free end of the fiber 15 is moved in a direction parallel to the axial direction and in a circumferential direction by the magnetic field of the magnet 18. , the toner captured by the fibers 15 is uniformly supplied to the developing roller 11 in the circumferential and axial directions.

Further, since the toner remaining in the sleeve 15a of the toner supply roller 12 is moved in one direction of the shaft, it is convenient to collect it in a hopper and reuse it. The configuration and effects of other parts of the sixth embodiment are the same as those of the first embodiment already described.

[Effects of the Invention] As described in detail above, according to the present invention, the fibers protruding perpendicularly from the surface of the toner supply means sufficiently capture toner by the magnetic field generated by the magnetic field generation means,
This toner is stably supplied to the developing roller via a fiber, and the necessary amount of sufficiently charged toner is stably attached to the latent image formed on the photoconductor, forming a clear toner image. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the overall structure of each embodiment of the present invention, FIG. 2 is an explanatory diagram of the configuration of main parts of the first to fourth embodiments of the present invention, and FIG. FIG. 4 is an explanatory diagram of the structure of the main part of the fifth embodiment of the invention, FIG. 4 is an explanatory diagram of the structure of the main part of the sixth embodiment of the invention, and FIGS. FIG. 3 is an explanatory diagram of the arrangement of fibers in an example. 1...Photoreceptor, 2...Charger, 3...
...Transfer device, 4...Cleaner, 4a...
...Brush, 5...Cleaning blade,
6... Static eliminator, 7... Case, 8...
...adhesive, 10...developing device, ↓work...
Developing roller, 12... Toner supply roller, 13... Agitator, 14... Thin layer blade, 15... Fiber, 15a...・
... Sleeve, 16A-16D ... Magnet, E
1 to E, 7... Bias power supply, T... Exposure position, D... Development position. Figure l

Claims (1)

[Claims] A developing device that visualizes a latent image formed on a photoreceptor by toner, a developing roller that brings toner into sliding contact with the latent image to visualize the latent image, and a developing roller disposed in contact with the developing roller,
A developing device characterized by having a toner supplying means in which fibers of a magnetic material are disposed to protrude from the surface in a direction perpendicular to the surface and supplying toner to the developing roller, and a magnetic field generating means for applying a magnetic field to the toner supplying means. Device.