JPS62247382A - Development device using two component developer - Google Patents

Abstract

PURPOSE:To form a stable uniform developer layer and to obtain an image having high quality by forming the carrier of the developer of a non-magnetic substrate and a magnetic particle layer which are placed in a monolayeron a substrate. CONSTITUTION:The state of forming magnetic ears composed of the thin film of the magnetic particles M stuck on the sleeve 3 of the developing device and the carrier C mounted on the thin film is the state is which the height of the magnetic ears of the carrier C is reduced as shown by the figure, thereby sufficiently giving magnetic force to the carrier, and the density of the ears is maintained to dense. Thus, in the non-contact developing system, a gap of between the image forming body 1 and the sleeve 3 is shortened. The magnetic particle M mounted on the sleeve 3 is composed of a sperical ferrite having magnetization of 80 e,m,v/g and 100mum particle size. The sticking of the magnetic particles M on the sleeve 3 is effected in such the way that an epoxy adhesives is spreaded thinly on the sleeve 3, and the magnetic particles are scattered on the sleeve, so as to form almost one layer of the thin dense film.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a developing device for developing an electrostatic latent image formed on an image forming body used in an electrophotographic copying machine or the like, and more particularly to an improvement in a developing device using a non-contact developing method using a two-component developer.

[Behind the invention! ]

In the electrophotographic method in which the electrostatic latent image on the image forming body is visualized by development to form the final image, there are currently two types of development methods: one using a component-based developer, and the other using a two-component developer consisting of a magnetic carrier and a non-magnetic toner. There are two main types of development methods: However, even in the development method using a -component type developer, in the development method using a -component non-magnetic developer, the force for supporting the developer on the developer carrier is due to the electric charge of the developer. It is difficult to form a stable and uniform developer layer using only Coulomb force and 7T der Waalska. Furthermore, in a developing method using a -component magnetic developer, since the toner generally contains a magnetic substance such as black magnetite powder, it is difficult to obtain toner with vivid colors other than black. On the other hand, a developing method using a two-component developer has advantages over other developing methods in that it forms a stable developer layer and can use brightly colored toners. Generally, when developing a latent image on an image forming member (photoreceptor) with a developer held and conveyed on a developer carrier, in order to increase the contrast of the resulting image, it is necessary to Image quality can be improved by reducing the body distance. If the gap between the image forming member and the developer carrier is made small, the developer layer can be transferred between the image forming member and the developer carrier in the contact type development method in which development is performed by bringing the image forming member and the developer layer into contact with each other. is compressed or under pressure:
In order to avoid destroying the latent image or the developed image, it is necessary to reduce the amount of developer held and conveyed on the developer carrier so as to keep it within an appropriate range. Note that the "amount of developer" herein refers to the weight of developer per unit area held on the surface of the developer carrier. Furthermore, even in a non-contact development method in which development is performed while maintaining the image forming body and the developer layer in a non-contact state, when the gap between the image forming body and the developer carrier is made small, the image forming body and the developer layer It is necessary to reduce the amount of developer on the developer carrier to keep it within an appropriate range so that the developer does not come into contact with the developer. In the conventional developing method using a two-component developer, for example, development is carried out using a developing device having the following configuration. FIG. 8 is a partially exploded view of a conventional developing device. In the figure, the developing roll has a north pole and a south pole at equal magnetic angles with equal magnetic force.
It consisted of a magnetic roll 104 whose poles were alternately magnetized, and a non-magnetic cylindrical developer carrying sleeve 103. And magnetic roll 104 and developer carrier 103
It is rotatable relative to the . A two-component developer containing carrier, toner, etc. is supplied onto this developing roll, and is conveyed by relative rotation of the magnetic roll 104 and sleeve 103 to a developing area facing the image forming body 101, for example, a photoreceptor drum. . Conventionally, in order to adjust the developer layer held on the developer carrier surface to the desired developer amount and developer layer thickness, a layer thickness regulating plate made of metal or resin as shown in Figure 8 was used. 105 is arranged close to the surface of the developer carrier 103, and the developer d is held on the surface of the developer carrier 103 and moves, slipping through the gap between the layer thickness regulating plate 105 and the surface of the developer carrier 103. It was constructed such that it was transported to the developing area. Among the developer on the developer carrying surface, the magnetic carrier receives a force from the magnetic field of the magnet of the magnetic roll 104 placed on the opposite side of the developer carrying surface, and depending on the magnetic force of the magnet and the magnetic property of the carrier, the magnetic carrier is 4 and stands up, and the carrier is held on the developer carrying surface. When the non-magnetic toner is stirred in the developer container 102, it is triboelectrically charged with the magnetic carrier, and the non-magnetic toner and the magnetic carrier have charges of opposite polarity and are bound to each other by Coulomb force. . Since the magnetic carrier is held on the developer carrying surface by the magnetic field of the magnet, the non-magnetic toner is also held on the developer carrying surface together with the magnetic carrier. A developer layer made of non-magnetic toner is formed. This developer layer is held and conveyed on the developer carrying surface, and develops the latent image on the image forming body 101. As described above, this developer layer is not compacted in the gap between the image forming body 101 and the developer carrier 102, and the pre-development layer does not come into contact with the image forming body 101, which should be kept in non-contact. The minimum conditions must be met,
In addition, ■ Toner adheres to the surface of the image forming body other than the image area.
9. The phenomenon of "fogging" does not occur. 9. The phenomenon of "carrier adhesion" in which carrier adheres to the surface of the image forming body does not occur. ■ Enough toner adheres to the latent image area to provide sufficient image density. ■ The toner image has enough gradation to reproduce the gradation of the latent image. The developer layer must satisfy the following conditions. In order to meet these conditions, the physical properties of the developer itself, the stirring method, the physical properties of the latent image carrier, the relative speed between the image forming body and the developer layer, the means for forming a latent image on the latent image carrier, and the an electrical bias applied between the forming body and the developer carrier;
1llDI that is suitable for the magnetic force of the magnet and the shape of the magnetic field.
Must be I. Among such conditions are
The appropriate range is even narrower than the above-mentioned minimum conditions because of the amount of developer on the surface of the developer carrier and the thickness of the developer layer. In order to make the layer thickness of the developer d around 1 mm or less by using such a method using the layer thickness regulating plate 105, the gap between the layer thickness regulating plate 105 and the surface of the developer carrier 103 must be set to 0. It must be around 5 mm or less. This is because when the developer d passes through the gap between the layer thickness regulating plate 105 and the developer carrier 103, it is pushed in and passes through as a high-density developer layer. After passing through the gap between the layer thickness regulating plate 105 and the developer carrier 103,
The developer d on the surface of the developer carrier 103 is transferred to the magnetic roll 10
4 rises up to form a low-density developer layer, and the developer l- is applied to the layer thickness regulating plate 105 and developer carrier 103.
The height is 1.5 to 3 times higher than when passing through the gap. In ordinary copying machines and printers that develop and visualize electrostatic latent images, the gap between the above-mentioned layer thickness regulating plate 105 and the surface of the developer carrier, which has an image width of several hundred units, is set at around 0°5 or In order to set the thickness uniformly and stably over the entire image width, it is difficult to carry out because highly accurate machining and highly accurate adjustment of the layer thickness regulating plate 105 are required.

[Problems to be solved by the invention]

The conventional method of adjusting the quality by adjusting the carrier magnetization, particle size, etc. has little freedom in selection, and if you take developability into consideration, it is difficult to stably produce and produce appropriate products. It was difficult to supply. On the other hand, if you try to control the height of the magnetic roll using a magnetic roll, you will need to lower the magnetic flux density, which weakens the force that holds the douyaria, making it more likely to cause carrier adhesion. When the amount of developer on the sleeve is reduced, the absolute amount of toner that contributes to development decreases, resulting in a lower image density.Furthermore, the height of the carrier and the roughness of the developer on the developing sleeve are , is determined by the magnetization and particle size of the carrier, and the magnetic flux density of the magnet roll.This is because, as shown in Figure 9, when the magnetic force of the carrier is strong, the force between the carriers, that is, the adhesion force F between the carriers is strong. In addition, since the virtues formed in parallel repel each other due to the guiballs formed within the carrier, the density of the virtues becomes coarser due to the repulsive force F2 between the carriers.

[Means for Solving the Problems] (Objective of 51!) The present invention provides a two-component developer containing a magnetic carrier and a non-magnetic toner that can use vivid color toners and form a stable developer layer. In the non-contact development method using
At the same time, it is possible to obtain high-quality images by stably and uniformly forming a thin developer layer that applies sufficient magnetic force to the carrier and maintains a high developer density on the developing sleeve. The purpose is to provide equipment. (Structure of the Invention) The above object is to form a layer of a two-component developer consisting of a carrier and a toner on a developer carrier, and to provide a developing device that develops an electrostatic latent image on an image forming member. This is achieved by a developing device using a two-component developer characterized by having a non-magnetic substrate and a layer of magnetic particles arranged in a single layer on the non-magnetic substrate. In the developing device of the present invention, the developer is composed of a toner having a particle size of 50 μm or less, preferably 15 μm or less, and a carrier having a small particle size that is not much different from the particle size of the toner, as described later. In this method, non-contact development is performed using an unprecedentedly thin developer layer for a two-component developer having a thickness of 300 μm or less, preferably 200 μm or less. Even if the particle size of the developer carrier and toner used here are small as in the previous stage, and the binding force between the two is weak, the developer layer is extremely thin, so the developer carrier ( (hereinafter referred to as the sleeve) and is not accompanied by scattering. In addition, in the case of non-contact development, unlike in the case of contact development, an unnecessarily large amount of developer layer is not required, and only the amount of toner necessary for image formation is present. By combining the development method with the non-contact development method, the advantages of both methods are doubled and the effect is increased. Moreover, by making the developer layer thinner in the non-contact development method, the gap between the image forming body (photoreceptor) and the sleeve can be reduced, and the developing bias voltage required to form the oscillating electric field required to fly the toner can be reduced. It can be lowered. Therefore, there is an advantage that not only the toner scattering is reduced from this point of view, but also leakage discharge due to the developing bias from the sleeve surface is suppressed. When the gap between the image forming body and the sleeve is made small, the latent image causes the toner in the developing area, that is, on the sleeve, to e? The intensity of the electric field formed in the area where it can be transferred to the image forming body by receiving the force of 1 becomes large, and as a result, even subtle changes in gradation and fine patterns can be developed well. As a means for forming the thin developer layer, for example,
Any of the conventionally known layer thickness regulating members, such as the sleeve, an N thickness regulating plate disposed with a certain gap between them, and a magnet roll disposed close to the sleeve that regulates the developer layer thickness by a rotating magnetic field. is used. In order to eliminate impurities such as dust, fibers, paper powder, or aggregates of toner or carrier contained in the developer, a thin layer forming member consisting of a pressure plate that is lightly elastically pressed against the sleeve. is preferably used. FIG. 4 shows a sectional view of a developing device suitable for carrying out the developing method of the present invention.
4 is a magnetic roll having N and S8 poles; 5 is a layer forming member;
6 is a fixing member of the member, 7 is a first stirring member, and 8 is a second stirring member. 9 and 10 are the stirring members, 7 and 8 are rotating shafts, 11 is a developer reservoir, 12 is a replenishment toner container, 1
3 is a toner supply roller, 14 is a developing bias power supply, 15
represents the development area, T represents the toner, and d represents the developer. As shown in FIG. 1, the structure of the developing roll of the developing device according to the present invention is characterized in that magnetic particles M having a particle size of 30 to 150 μm are arranged in a thin layer and fixed on a sleeve 3. be. This attachment method includes applying a thin layer of epoxy adhesive onto the sleeve 3 and attaching the magnetic particles M thereon, or attaching double-sided adhesive tape on the sleeve 3 in advance, and then attaching it to the adhesive. There are methods of attaching magnetic particles M, etc. The above-mentioned attachment can be easily formed by attaching a certain amount of magnetic particles M onto the sleeve 3 and then rotating the magnetic roll 4. The effect of the sleeve of the present invention formed in this way is that since the magnetic field is concentrated on each magnetic particle M, carriers adhere to each magnetic particle M and form ears, thereby forming a highly dense carrier chain. It is possible to form. FIG. 2(A) is a diagram schematically showing a magnetic tip of a carrier C formed on a sleeve 103 of a conventional developing device.
As shown in FIG. 9 above, long ears are formed, and each ear is formed with a coarse density. On the other hand, FIG. 2(B) shows a thin layer of magnetic particles M stuck on the sleeve 3 of the developing device according to the present invention, and this ri
FIG. 3 is a diagram schematically showing a magnetic ear formation state of carrier C formed on a layer. According to this, the height of the carrier Cm can be reduced, sufficient magnetic force can be applied to the carrier, and the density of the ears can be kept high. This has made it possible to shorten the gap between the image forming body 1 and the sleeve 3 in the non-contact developing system. Also, Figure 3 (A) is a diagram showing the magnetic flux distribution of the conventional developing roll. 3(B) is a diagram showing the magnetic flux distribution according to the present invention. In FIG. 3(B), the magnetic flux density increases because it is focused by the magnetic particles M. The magnetic particles M have a magnetization of 80e
yll+uy/g, a spherical 7-elite with a particle size of 100μI. Furthermore, in order to attach the magnetic particles M onto the sleeve 3, spread the epoxy adhesive thinly on the sleeve 3, and then sprinkle the magnetic particles M onto the sleeve 3, so that it becomes a thin, dense layer. It was formed. In such a developing device, the developer d in the developer reservoir 13
The first stirring member 7 rotates in the direction of the arrow, and the second FR stirrer 8 rotates in the opposite direction so as to overlap with each other.
The mixture is sufficiently agitated and mixed, and is adhered to and conveyed to the surface of the sleeve 3 by the feeding force of the sleeve 3 rotating in the direction of the arrow and the magnetic roll 4 rotating in the opposite direction. A fixing member 6 extending from the housing 2 is provided on the surface of the sleeve 3.
The layer forming member 5 held by is pressed against the surface near the end to regulate the layer thickness of the developer d being conveyed,
10μ pupil to 300μ bell, preferably 50μff1-20
A thin developer layer with a gloss level of 0μ is formed. Here, if it is less than 10 μm, the development density will decrease and 250 μm.
When the value exceeds the μ mark, carrier and toner scattering occurs. This developer layer develops the latent image on the image forming body 1 rotating in the direction of the arrow in the developing area 15 at a distance and without contact, thereby forming a toner image. During this non-contact development, a developing bias containing an alternating current component is applied to the sleeve 3 from the IL source 14, and as a result, only the toner in the developer on the sleeve 3 selectively moves to and adheres to the surface of the latent image. be done. Note that the layer thickness of the developer is measured as follows. That is, using a two-con profile projector manufactured by Nippon Kogaku Co., Ltd., the layer thickness is determined by comparing the positions of the projected image of the screen on the sleeve and the projected image of the thin layer formed on the sleeve. The layer forming member 5 is an extremely uniformly formed thin plate made of, for example, magnetic or non-magnetic metal, metal compound, plastic, rubber, etc., to which the discharge 1 is fixed by a fixing member 6 and imparted with elasticity. , its thickness is 50 to 500 μm. As described above, the sleeve 3 is elastically slightly pressed at a portion near the other end of the layer forming member having one end fixed, and this pressing causes the carrier and toner particles to be released at the contact position between the sleeve 3 and the thin plate. Only the layer is allowed to pass through, and impurities in the developer d, aggregates of carrier and/or toner, etc. are not allowed to pass through. Therefore, the developer reaching the development area 15 is always uniform and stable. The thickness of the developer reaching the developing area 15 is controlled by changing the pressing force and contact angle of the layer forming member 5 against the sleeve 3. As mentioned above, it is said that it is advantageous for the carrier and toner constituting the developer to have a small particle size from the viewpoint of image quality resolution and hierarchical reproducibility. For example, even when the carrier in the developer layer has a small particle size of 30 μI or less, By using a means such as the layer forming member 5 described above, impurities, particles, etc. in the developer can be automatically removed to form a uniform layer. Furthermore, even when the carrier has a particle size as small as that of the toner, contamination of impurities is similarly eliminated and uniform layer formation is possible. The two stirring members 7 and 8 incorporated in the developing device are constructed so that the stirring blades overlap each other without colliding with each other, so that sufficient stirring in the left and right direction (FIG. 4) is achieved. , Due to the inclination of the stirring plate, sufficient stirring is also carried out in the front-rear direction (!#14 diagram). Further, the toner T supplied from the hopper 11 via the supply row 212 is also uniformly mixed into the developer d in a short time. The developer d, which has been sufficiently agitated and imparted with a desired frictional charge as described above, is regulated by the layer forming member 5 in the process of being deposited and conveyed onto the sleeve 3 to form an extremely thin and uniform developer layer. Ru. This developer layer is conveyed in one direction by the rotation of the sleeve 3, and a magnetic bias having a vibration component is generated by the rotation of the magnetic roll 4 in the opposite direction, causing a complicated movement such as rolling on the sleeve 3. Therefore, when the toner reaches the development area 15 and develops the latent image on the image forming member 1 without contact, the toner is effectively supplied toward the latent image surface. The developer layer has a thickness of 10 μm to 250 μm as described above.
Since it is approximately 200 μm, the gap between the image forming body 1 and the sleeve 3, that is, the development gap, can be narrowed to around 200 μm to enable non-contact development. When the development gap is narrowed in this manner, the electric field in the development region 15 becomes larger, so that sufficient development can be achieved even if the development bias applied to the sleeve 3 is small, and there is an advantage that leakage discharge of the development bias and the like is reduced. iL et al. generally improve the resolution and other image quality of images obtained by development. The developing method using an extremely thin developer layer as described above exhibits remarkable effects, for example, in a developing device with a small diameter sleeve. That is, conventionally, when non-contact development is performed using a small-diameter sleeve of, for example, about 30 m5 or less, a development gap of about 11 mm is required because it is difficult to regulate the thickness of the developer layer. For this reason, a high-voltage alternating current bias is required, which reduces the resolution, gradation reproducibility, and overall image quality of the image obtained through development, and has the disadvantage that details such as letters in particular are crushed and cannot be reproduced satisfactorily. . On the other hand, according to the developing device of the present invention, it is possible to form a uniform, stable and thin developer layer for development, so the development gap can be made small, and the electric field is sufficiently large so that the developed image can be formed. The resolution, gradation reproducibility, and other image quality have been significantly improved. Furthermore, if a small-diameter sleeve is possible, the expensive developing device becomes smaller and costs are reduced, and in color electrophotography, etc., where many developing devices are required, it becomes easier to arrange the imaging equipment, making the entire device more compact. It has the advantage of Another advantage of the developing device of the present invention is that scattering of the carrier and toner is suppressed to a small extent despite the small particle size. That is, when developing using a conventional developer consisting of carrier and toner with small particle diameters, the carrier and/or toner may scatter and contaminate the inside of the device, or toner of a different color may get mixed into the developing device that accommodates color toner. The color balance of the image may be disturbed.
Although there have been problems such as fogging, all of the above problems can be solved by the developing method of the present invention. Another effect of the present invention is that the developing method is non-contact resolution development, and only the toner is developed by selectively flying toward the latent image surface, so that carrier adhesion to the latent image surface is prevented. Ru. In addition, since the latent image surface is not rubbed, there is no damage to the image forming body surface or the formation of scratches, and the developing power and gradation reproducibility are good, and a sufficient amount of toner can be applied to the latent image. Can be attached to surfaces. Furthermore, since the toner image can be superimposed on the image forming body and developed, it is suitable for the multicolor development of the present invention. In addition, as stable development conditions in the developing method of the present invention, the developer layer has a diameter of 10 to 250 μm, preferably 20 to 250 μm.
The sleeve 3 has a 200 μm definition and a developing gap of 200 μm to 600 μm, preferably 300 to 500 μm.
The rotational speed of is 1 in linear velocity compared to the rotational speed of the image forming body 1.
- It is preferably 5 times or more, preferably 2 times or more. There is no particular limitation on the above, but there is a problem of carrier and toner scattering, so it is necessary to keep it below a suitable value. The magnetic particles M used in the present invention have a magnetization of 30 to 150
e+awuy/g and a particle size in the range of 20 to 250 μm is used. And as for the material, 7elite,
Many magnetic materials such as iron and nickel can be used. Moreover, it is better if the shape is spherical and the particle diameter is uniform. Further, the average particle size of the magnetic particles M is preferably in the range of 1/2 to 3 times the average particle size of the carrier C. Good results are also obtained with resin-coated materials. Next, the composition of the toner of the developer applied to the developing device of the present invention is as follows. ■ Thermoplastic resin (binder) 80-90wt% Examples: polystyrene, styrene acrylic polymer, polyester, polyvinyl butyral, epoxy resin, polyamide resin,
Polyethylene, ethylene-vinyl acetate copolymer, etc., or a mixture of the above Pigment (coloring agent) θ ~ 15 wt% Example: Black: Carbon Plaque Yellow: Bennonone derivative Magenta: Rhodamine B lake, Carmine 6B, etc. Cyan: Copper 7 Taroshi 72 ■ Electron control agent 0-5wt% Positive donor: Nigrosine-based electron-donating dye, flukoxylated amine, alkylamide, chelate, pigment, 4
Negative toners such as ammonium salts, 1 fl complexes with two-electron acceptability, chlorinated paraffins, chlorinated polyesters, polyesters with excess acid groups, chlorinated copper phthalocyanines, etc. Examples of fluidizing agents: Frogl silica, hydrophobic silica, silicon Varnishes, metal soaps, nonionic surfactants, etc. ■ Cleaning agents (prevents toner filming on the photoreceptor) Examples: fatty acid metal salts, silicon oxides with organic groups on the surface,
Fluorine surfactants, etc. ■ Fillers (Improves image surface gloss, reduces raw material costs) Examples: Calcium carbonate, clay, talc, pigments, etc. In addition to these materials, to prevent fogging on the image surface and toner scattering. , a small amount of magnetic powder may be included. As such magnetic powder, triiron tetroxide, γ-ferric oxide, chromium dioxide, nickel 7-erite, iron alloy powder, etc. with branch threads of 0.1 to 1 mm are used, and 0.1 to 5 t% Contains. In order to maintain even clearer colors, it is desirable that the content be 1wL% or less. Suitable resins for pressure fixing toners that are plastically deformed and fixed to paper with a force of about 20 kg/c- include wax, polyolefin, ethylene vinyl acetate copolymer, polyurethane, and adhesive resins such as rubber. used. A toner can be made using the above-mentioned materials by a conventionally known manufacturing method. In this apparatus, in order to obtain a more preferable image, the toner particle size (weight average) is 50 to 1 μm, particularly 15 to 1 μm.
It is preferable to use a spade; if the field exceeds 15μ, the image quality will deteriorate somewhat, especially if the field exceeds 50μ, fine print becomes difficult to read, and if the field exceeds 1μ, fogging will occur and the sharpness of the image will be lost. The particle size or average particle size of the toner and Kya I77 in the present invention means a weight average particle size, and the weight average particle size is a value measured with a Coulter Counter (manufactured by Coulter Inc.). The specific resistance of the particles is determined by placing the particles in a container with a cross-sectional area of 0.50 cm, tapping them, applying a load of 1 kg/am2 to the packed particles, making the thickness about 1-1, 102~10'V/C- between
It is determined from the current value that flows when an electric field is generated. The structure of the carrier is as follows, and basically the materials listed as the constituent materials of the toner are used. The carrier particles are mainly composed of magnetic particles and resin, and are preferably spherical in order to improve resolution and gradation reproducibility, and have a weight average particle size of 50 μl or less, particularly 5 μm or more and 30 μm or less. Preferably. If the carrier particle diameter exceeds 30 μm, particularly 50 μm, formation of the i1 layer in the developer layer is inhibited, developability deteriorates, and image quality deteriorates. If it is less than 5 μm, the developability, friction, and fluidity of the developer will be poor, and carrier scattering will occur. In addition, in order to prevent charges from being injected by the bias voltage and causing the carriers to adhere to the photoreceptor surface and to prevent the charges forming the latent image from disappearing, the resistivity of the carrier is set to 10-Ωa.
It is preferable to use an insulating material having an insulating value of 10'4 ΩC or more, preferably 10'3 ΩC- or more, and more preferably 10'4 ΩC1 or more. These various carriers are made by coating the surface of a magnetic material with I'j (oil) or by dispersing fine magnetic particles in a resin, and selecting the resulting particles using a known particle size selection means. Furthermore, if you want to make Yaria spherical now, do it as follows: ■ Resin-coated carrier: Select spherical magnetic particles. ■ After forming magnetic powder dispersed carrier bidisperse m fat, do it with 1% wind!
Apply water spheroidization treatment or spray l'ly method 1
:, 1:')iE[*forms spherical dispersed coral. It is preferable to mix the toner and carrier described above in such a ratio that the total surface area of each toner is equal. For example, when the average particle size of the toner is 10 μm and the average particle size of the carrier is 20 μm, the toner concentration (weight ratio of toner to developer) is 5 to 40 wt%, preferably 10 to 40 wt%.
It is appropriate to set it to 25 wt%. That is, in the developer of the present invention, unlike a conventional developer in which a large number of small-particle toner particles are attached to the outer periphery of a large-particle carrier, the carrier particle size is small and close to the toner particle size. Therefore, it is preferable that the mixing ratio be such that the sum of the surface areas of the two is approximately equal. [Examples] The present invention will be specifically explained below with reference to Examples. FIG. 5 shows the structure of the image forming apparatus to be used.
The dimensional color CCD image pickup device 24 is integrated into two nits, and the image input section IN is moved in the direction of arrow X by a drive device (not shown), and the CCDI image device 24 reads the original. The image input section IN may be fixed and the document 25 may be moved by moving the document table. The image information read by the image input unit IN''C is converted into data suitable for recording in the image processing unit TR. A latent image is formed on the image forming body 20, and this latent image is developed to form a toner image on the image forming body 20.The surface of the image forming body 20 is uniformly charged by a scorotron charging electrode 27.Subsequently, a laser optical Image exposure according to recorded data from the system 26 is applied to the image forming body 20 via a lens.
irradiated on top. In this way, an electrostatic latent image is formed. This electrostatic latent image is developed by the developing device A which contains yellow toner. Receives image exposure according to recorded data. The formed electrostatic latent image is developed by a developing device B containing magenta toner. As a result, a two-color toner image of yellow toner and 7-zenta toner is formed on the image forming body 20. Thereafter, the cyan toner and the black toner are developed in a similar manner, and a four-color toner image is formed on the image forming body 20. Note that the developing device A accommodates the toners of each color. B, C, and D all have the same structure as the developing device shown in Figure #44. The multicolor toner image obtained in this way is transferred to the exposure lamp 2.
8, the transfer pole 29 is easily transferred.
The image is copied onto the recording paper P. The paper P is separated from the image forming body 20 by a separation pole 30 and fixed by a fixing device 31. On the other hand, the image forming body 20 is cleaned by the removing electrode 32 and the cleaning device W133. The cleaning device fi33 has a cleaning blade 34 and a seven-hoo brush 35. These are kept out of contact with the image forming body 20 during image formation, and when a multicolor image is formed on the image forming body 20, they come into contact with the image forming body 2o to scrape off residual toner after transfer. Thereafter, the cleaning blade 34 separates from the image forming body 20, and a little later, the seven-ear brush 35 separates from the image forming body 20. 7. The arbrush 35 functions to remove toner remaining on the image forming body 20 when the cleaning plate 34 is separated from the image forming body 20. 36 is F with blade 34! This is a roller that collects the toner that has been scraped off. In FIG. 8 showing the laser optical system 2B, 37 is a semiconductor laser oscillator, 381. is a circular polygon mirror, 39 is rθ
It's a lens. In addition, in such an image forming apparatus, in order to align each image, it is effective to place an optical mark on the photoreceptor and read it with an optical sensor to determine the timing for starting image exposure. . In the image forming process in the copying apparatus shown in FIG. 5, reversal development is performed using a developer having the following formulation, and image formation is performed under the image forming conditions shown in Tables #11 to 4 and the operation timing shown in FIG. (In Figure 7, the high level indicates the operating state.) (Developer formulation) Toner composition: Polystyrene 45 parts by weight Polymethyl methacrylate 44 parts by weight Parifast 0.2〃 (Charge control agent) Arrival Colorant 10,5//Magnetite powder 0.3 However, the colorant is Auramine for the yellow toner, Rhodamine B for the magenta toner, Copper 7 Taloshi 7 nin for the cyan toner, and Carbon black for the black toner. The above composition is mixed, ground and classified to obtain a desired toner. Carrier composition Styrene-methyl methacrylate (1:1) copolymer resin 30 parts by weight 1 part magnetite powder
7 Qtt The above composition is mixed, kneaded, classified and then treated with hot air to obtain a spherical carrier.0 Next, 80 ffl parts of the above carrier and 20 toner! I! Thoroughly stir and mix the amounts in Table 1, Table 4, Table 2, Table 3, and Table 1. The photosensitive layer has a carrier generation layer containing a tris7zo pigment as a lower layer and a carrier transport layer containing an aromatic amino compound as an upper layer.8! The photosensitive layer is composed of a photosensitive layer of a functionally separable type, and the development method is a non-contact development method and a reversal development method. In addition, in the timing chart of Fig. 7, the horizontal axis represents the image creation process, the vertical pongee represents each image creation department, and A, B, C, D
represents a yellow toner developer, a magenta toner developer, a cyan toner developer, and a black toner developer. When a multicolor image was formed under the above conditions, an image with good resolution and good reproducibility of dot-like halftones was obtained. Furthermore, the scattering of toner and carrier could also be suppressed to a minimum. (Example 2) Next, the weight of Bali 7 First of the toner composition was 0.4,
Example 1 except that the image forming conditions were as shown in Tables 5 to #48.
A multicolor image was formed in the same manner as above. When a multicolor image was formed under the above conditions as shown in the following margins, Table 5, Table 8, Table 6, Table 7, it was found that, as in Example 1, it had high resolution and good color tone and gradation without scattering of toner and carrier. A copy image with good tonal reproducibility was obtained.

【Effect of the invention】

As is clear from the above description, by using the developing sleeve equipped in the developing device of the present invention, it is possible to form a developer layer with low density and high density on the sleeve. By narrowing the gap in the developing area between the forming body and the sleeve, high image quality with high image density and resolution without carrier adhesion, scattering of carrier or toner, or fog can be obtained. It is possible to obtain clear multicolor images with excellent color tone and gradation reproducibility. Further, by using a small sleeve for non-contact development, the color copying apparatus can be made more compact.

[Brief explanation of drawings]

Figure 1 is a partial sectional view of the developing roll of the developing device according to the present invention, Figure 2 is a diagram showing the state of formation of the developer layer on the developer carrier, and Figure #13 is a diagram showing the state of formation of the magnetic flux density on the carrier. FIG. FIG. 4 is a sectional view of a developing device using the present invention;
FIG. 5 is a cross-sectional view of the configuration of an embodiment of a copying apparatus equipped with the copy station IIc, FIG. 6 is a configuration diagram of the laser optical system of the copy 'am, and FIG. 7 shows the image forming timing in the embodiment. FIG. FIG. 8 is a partial sectional view of a conventional developing device, and FIG. 9 is an enlarged view showing the state of carrier formation on a developer carrier in a comb-like manner. 1, 20.101---Image forming member (photoreceptor) 3,
103----1 developer carrier (developing sleeve) 4,
104----1 magnetic roll (magnet) 5, 1
05---- One layer thickness regulation plate (1! Cutting plate) 7.8---
-1 Stirring member 14---1 Development bias power source 15---1 Development areas A, B, C, D---1 Developing device c---Carrier d---1 Developer M--- −
--Magnetic particles T----)ner Applicant: Konishiroku Photo Industry Co., Ltd., 2a Sajite M Figure 5 Figure 6

Claims (5)

[Claims] (1) In a developing device that forms a two-component developer layer consisting of carrier and toner on a developer carrier and develops an electrostatic latent image on an image forming member, the nuclear developer carrier is a non-magnetic substrate. A developing device using a two-component developer characterized by having a layer of magnetic particles arranged in a single layer thereon. (2) A developing device using a two-component developer according to claim 1, wherein the average particle size of the magnetic particles is 1/2 to 3 times the average particle size of the carrier. (3) The thickness of the first developer layer is 30 μm or more, 300 μm or more
A developing device using the two-component developer according to claim 1 or 2, characterized in that the developer has a particle size of .mu.m or less. (4) Any one of claims 1 to 3, wherein the developer layer is held on the developer carrier so as not to come into contact with the image forming body. A developing device using the two-component developer described in . (5) The method according to any one of claims 1 to 4, characterized in that an electrical and/or magnetic bias having a vibrational component is applied to the developer layer. A developing device that uses two-component developer.