JPS6252565A - Developing method - Google Patents

Abstract

PURPOSE:To form a color image having excellent resolving power and gradation reproducibility as well as color balance, etc. by forming thin layers of two-component developers consisting of a carrier and toner on plural developer conveying bodies and repeating plural times the stage for developing the latent image on an image forming body with at least one of the thin layers. CONSTITUTION:The thin layers of the two-component developers consisting of the carrier and toner are formed on the plural developer conveying bodies and the stage for developing the latent image on the image forming body with at least one of the thin layers is executed plural times, by which the multi-color toner image is formed on the above-mentioned image forming body. More specifically, the developer is constituted of the toner having <=50mum, more preferably <=15mum grain size and the carrier of the small grain size which does not differ so much from the grain size of the toner. The latent image is developed without contact by the developer layer as thin as preferably <=200mum which is not possible heretofore in the developing region. Since the developer layer is made extremely thin, the developer layer is thoroughly fixed to the developer conveying bodies and is prevented from splashing. The developing gap is thus made smaller. Since an electric field is thereby made substantially large, the resolving power and gradation reproducibility and other image quality of the developed image are considerably improved.

Description

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

The present invention relates to an image forming body, and particularly to a method for developing a latent image on an image forming body used in color electrophotography or the like.

[Conventional technology]

Conventionally, various methods as shown below have been proposed as multicolor image forming methods using electrophotography. One of these is to repeat the charging, exposure, development, and transfer steps for each color component to superimpose each color toner image on the recording paper. An O'7r1 latent image is formed according to each color component data, developed with yellow, magenta, cyan, or black toner, and transferred onto a transfer material such as recording paper or overhead projection film.The above process is performed in one color. A multicolor image is formed on the transfer material by applying each component one by one. However, in this method, each color must be transferred to the transfer material each time development is completed, which increases the size of the device and increases the image forming speed. It takes a long time. ■ There are disadvantages such as the possibility of positional deviation due to repeated operations. 佽-悉 "外" (Improvement of Conventional Example 1) Multiple toner images on the same image forming body such as a photoreceptor A multicolor image forming method has been proposed in which the above-mentioned drawbacks are solved by superimposing and developing the images and completing the transfer process only once.A preferred embodiment of this technique is to use an alternating current component in the developing device during the second and subsequent development. A method has been proposed in which a multicolor image is formed by applying a bias with a weight of Since the layer does not rub against the toner image formed up to the previous stage, image disturbance does not occur.The principle of this multicolor image forming apparatus will be explained below with reference to chart 70 in FIG. 5.MS5 The figure shows changes in the surface potential of the image forming body, which is a photoreceptor, and takes as an example the case where the charging polarity is positive.pH is the exposed area of the image forming body, and DA is the unexposed area of the image forming body. , DUP is exposure 55 +) H1,
m shows the increase in potential caused by the adhesion of positively charged toner T1 during development of fj&-. In the figure, the image forming body is uniformly charged by a charger and has a constant positive surface potential E. (2) The first image exposure using a laser, cathode ray tube, or LED as an exposure source is completed, and the potential of the pH of the exposed area decreases according to the amount of light. (2) The electrostatic latent image thus formed is developed by a developing device to which a positive bias approximately equal to the surface potential E of the unexposed area is applied. As a result, the positively charged toner T adheres to the exposed portion 1)H, which has a relatively low potential, and a first toner image is formed. The potential of the head on which this toner image is formed increases by DUP due to the adhesion of the positively charged toner T, but normally it does not reach the same potential as the unexposed area D^. ■ Next, the surface of the image forming body on which the first toner image has been formed is charged a second time by a charger, and as a result, the toner T
Regardless of the presence or absence of , a uniform surface potential E is obtained. (2) A second image exposure is performed on the surface of this image forming body to form an electrostatic latent image. (2) Similarly to (2) above, positively charged toner T2 having a different color from toner T1 is developed to obtain a second toner image. By performing the above process multiple times, a multicolor toner image is obtained on the image forming body. A multicolor recorded image can be obtained by copying this onto a transfer material and fixing it by heating or applying pressure. In this case, the toner and one charge remaining on the surface of the image forming member are removed and used for the next multicolor image formation. In the method illustrated in FIG. tpJ5, at least the developing step (2) is performed in such a way that the developer layer does not come into contact with the surface of the image forming member. In the multicolor image forming method, a step of eliminating electricity from the surface of the image forming body may be provided before the second and subsequent charging. Furthermore, the exposure sources used for each image exposure may be the same or different. In electrophotography, image exposure means include gas or semiconductor laser light, LED, CRT, liquid crystal, etc.
is used. In addition to the above-mentioned electrophotographic method, methods for forming a latent image for forming a multicolor image include a method in which electric charges are directly injected onto the image forming body using a multi-needle electrode, etc., and a method in which an e-electronic latent image is formed by directly injecting charges onto the image forming body using a porcelain head. For example, a method of forming a magnetic latent image can be used. In such a color image forming method, toner abrasion WI
A two-component developer consisting of a non-magnetic or slightly magnetic toner and a magnetic carrier is preferably used because charging can be easily controlled and developing properties are excellent. In darkening developers, attempts have been made to reduce the particle diameters of carriers and toners in order to improve the resolution and gradation reproducibility of the resulting images, as well as the general image quality. For example, the patent application No. 58-238 proposed earlier by the present applicant
296, Japanese Patent Application No. 59-22018, etc., the conventional large particle diameter carrier of 50 to 500 μm was replaced with a carrier of 30 μm or less, and the particle size of the toner to be mixed was set to 15 μm or less. A technique for developing in a non-contact reversal development method using a developer is described.

[Problem that the inventor attempts to solve]

However, when the carrier in the developer has a small particle size,
The bonding force between the developer transport body and toner becomes weak, and the carrier and toner scatter during developer handling and the process of color image formation, contaminating the inside of the device, or adhering to the image surface, causing fog. , there are problems such as not being able to obtain a clear S image. Furthermore, toner of a different color was mixed into the developing device.
Problems such as the color balance of the image are disturbed also occur. As a result of intensive studies, the inventors of the present invention discovered that the above-mentioned problems are closely related to the thickness of the developer layer reaching the development area in relation to the non-contact development method, and were able to complete the present invention. That's what happened.

[Means to solve the problem]

(Objective of the Invention) The object of the present invention is to prevent scattering of the carrier and toner even though the carrier has a small particle size, thereby preventing contamination of the inside of the device, occurrence of image blurring, and mixing of different color toner. It is an object of the present invention to provide a developing method that achieves extremely uniform development without causing any problems, thereby making it possible to form color images with excellent resolution, gradation reproducibility, color balance, etc. (Structure of the Invention) The above object is a step of forming a thin layer of a two-component developer consisting of a carrier and a toner on a plurality of developer conveying bodies, and developing a latent image on an image forming body with at least one thin layer. This is achieved by a developing method in which a multicolor toner image is formed on the image forming body by performing the steps a plurality of times. In the developing method of the present invention, the developer is composed of a toner with a particle size of 50 μm or less, preferably 15 μm or less, and a carrier with a small particle size that is not much different from the particle size of the toner, as described later, and in the developing area. , 300 .mu.m or less, preferably 200 .mu.m or less, which is an unprecedentedly thin developer layer for non-contact development. Even if the bonding force between the developer carrier and toner used here is small due to the small particle size as described above, the developer layer is extremely thin and the developer carrier is (hereinafter referred to as the sleeve) and is sufficiently fixed to the sleeve without 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 all that is required is the presence of the toner necessary for image formation. By combining it with a non-contact developing method f), the advantages of both methods are doubled. Moreover, by making the developer layer thinner in the non-contact development method, the gap between the image forming body and the sleeve can be reduced, and the voltage of the developing bias required to form the oscillating electric field required to cause the toner to spread can be reduced. can. 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 smaller, the electric field strength formed by the latent image in the developing area increases, and as a result, subtle changes in gradation and fine patterns can be developed better. . For example, a regulation plate placed with a certain gap from the sleeve, a rotating magnetic field placed close to the sleeve, Any conventionally known WJ thickness regulating member such as a magnetic roll regulating the developer NJ thickness can be used. Among these, 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 contact plate that is lightly elastically pressed against the sleeve is used. Preferably used. FIG. 1 shows a sectional view of a developing device suitable for carrying out the developing method of the present invention. In the figure, 1 is an image forming body, 2 is a housing, 3 is a sleeve, 4 is a magnetic roll having N and S8 poles, 5 is a WiIVJ forming member, 6 is a fixing member for this member, 7
Is it 1st? 5th! The stirring member 8 is a second stirring member. 9 and 10 are rotating shafts of the stirring members 7 and 8, 11 is an M-feed toner container, 12 is a toner supply roller, 13 is a developer reservoir,
14 is a developing bias power supply, 15 is a developing area, T is a toner, and D is a developing device. In this developing device, the developer pool in the developer reservoir 13 is sufficiently agitated and mixed by the first stirring member 7 rotating in the direction of the arrow and the second stirring member 8 rotating in the opposite direction so as to overlap with each other. , sleeve 3 rotating in the direction of the arrow
The material is adhered to the surface of the sleeve 3 and is transported by the transporting force of the magnetic roll 4 rotating in the opposite direction. A thin layer forming member 5 held by a fixing member 6 extending from the sleeve 3 is pressed against the surface near the end of the sleeve 3 to regulate the layer thickness of the developer to be conveyed.
0μI11-300μm, preferably 50μm-200
A thin developer layer is formed in the area of the mu eyelid. Here, if it is less than 10 μm, the development density will decrease, and if it is 300 μm
If the amount exceeds 100%, carrier and toner scattering will occur. This developer layer develops the latent image on the image forming body 1 rotating in the direction of the arrow in the development area 15 without contacting the gap, 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 power source 14, and as a result, only the toner in the developer on the sleeve 3 is selectively transferred and attached to the surface of the latent image. . Note that the layer thickness of the developer is measured as follows. That is, using a Nikon profile projector manufactured by Nippon Kogaku Co., Ltd., the layer 17 is determined by comparing the positions of the projected image of the screen of the sleeve and the projected image of the thin layer formed on the sleeve. The thin layer forming member 5 is made of, for example, a magnetic or non-magnetic metal, with one end fixed by a fixing member 6 and imparted with elasticity.
It is an extremely uniformly formed thin plate made of a metal compound, plastic, rubber, etc., and its thickness is 50 to 50 h. Due to this pressure, only a thin layer of carrier and toner particles can pass through at the contact point between the sleeve 3 and the thin plate, and the developer is removed. Impurities, carrier and/or toner aggregates, etc. are not allowed to pass through.Therefore, the developer layer reaching the development area 15 is always made of Wi debris, and a uniform and stable product is obtained. The thickness of the developer to be achieved is controlled by changing the contact force and contact angle of the thin layer forming member 5 with respect to the sleeve 3. As mentioned above, the carrier and toner constituting the developer have smaller particle diameters. is said to be advantageous in terms of resolution and gradation reproducibility of image quality. For example, even when the carrier in the developer layer has a small particle size of 30 μm or less, development can be performed by using means such as the Tg fVJ forming member 5 described above. A uniform thin layer can be formed by automatically eliminating impurities and agglomerates in the carrier.Furthermore, even when the carrier has a particle size as small as that of the toner, contamination with impurities is similarly eliminated. It is possible to form a uniform thin layer.A perspective view and a front view showing the specific structure of the stirring member 7 and V8 incorporated in the developing device are shown in FIGS. 2(A) and 2(B). Inside 7a, 7b. 7c is the stirring blade of the first stirring member, 8a, 8f), 8c is the stirring blade of the second stirring member, and there are various types such as square plate blade, disc blade, elliptical plate blade, etc. Kaiken Tsumugi 9 and 10
are fixed at mutually different angles and/or positions. The two stirring members 7 and V8 are capable of sufficiently stirring the stirring blades so that they overlap each other without colliding with each other, and because of the inclination of the stirring plate (Fig. 152),
The stirring shown in FIG. 1) is also carried out sufficiently. Further, the toner T supplied from the hopper 11 via the supply row 212 is also uniformly mixed into the developer tank in a short time. The developer layer that has been sufficiently stirred and given a desired frictional charge as described above is regulated by the thin layer forming member 5 during the process of being deposited on the sleeve 3 and being conveyed, forming an extremely thin and uniform developer layer. be done. This developer layer is conveyed in one direction by the rotation of the sleeve 3.
At the same time, rotation of the magnetic roll 4 in the opposite direction generates a magnetic bias having an oscillating component, and the sleeve 3
Since it makes complicated movements such as rolling, when it reaches the development area 15 and develops the latent image on the image forming body 1 without contact, the toner is effectively supplied toward the latent image surface. . As mentioned above, the developer layer has extremely m layers (10
Since the size is μb, non-contact development is possible by narrowing the distance between the image forming body 1 and the sleeve 3. When the development gap is narrowed in this way, the electric field in the development area 15 increases, so
There is an advantage that sufficient development can be achieved even if the development/< ias applied to the sleeve 3 is small, and leakage discharge etc. of the development/< ias are also reduced. Furthermore, the resolution and other image quality of images obtained by development are generally improved. 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 m + s or less, a development gap of about 1 m 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 method of the present invention, since an extremely thin developer layer is formed and developed, the development gap can be made small, and the electric field is sufficiently large, so that the resolution of the developed image is improved. , gradation reproducibility and other image quality are significantly improved. In addition, if a small-diameter sleeve is possible, the expensive developing device becomes smaller and costs are reduced, and it becomes easier to arrange image-forming equipment for color electrophotography, etc., which require many developing devices, making the entire device more compact. There is an advantage that Another advantage of the developing method of the present invention is that scattering of the carrier and toner can be 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 some problems such as fogging, the developing method of the present invention solves all of the above problems. Another effect of the present invention is that the developing method is non-contact development, and only the toner is selectively developed 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 surface of the image forming body or the formation of brush marks, and the resolution and gradation reproducibility are good. can be attached to. 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 development method of the present invention, the developer layer has a thickness of 10 to 300 μm, preferably 20-300 μm.
20011 In, development gap is 200μm-700
It is preferable that the rotation speed of the sleeve 3 is at least 1.5 times, preferably at least twice the linear speed of the rotation speed of the image forming member 1. Next, the toner depletion of the developer applied to the developing method of the present invention is as follows. ■ Thermoplastic resin (binder) 80-90 LIIL% example:
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) 0 to 15 wt% Example: Carbon black yellow: Benzinone derivative magenta: Rhodamine B lake, carmine 6B, etc. cyanide phthalocyanine, sulfonamide derivative dye, etc.Charge control agent 0-5wt% Positive donor: Nigrosine-based electron donating dye, alfoxylated amine, alkyl amide, chelate, pigment , 4
Negative toners such as ammonium salts: Electron-accepting organic complexes, chlorinated paraffins, chlorinated polyesters, polyesters with excess acid groups,
Chlorinated so-called 7-thalocyanine, etc. ■ Examples of fluidizers: Colloidal silica, hydrophobic silica, silicone varnish, metal soap, nonionic surfactants, etc. ■ Cleaning agents (prevents toner filming on the photoreceptor) Examples: Fatty acid metals salt, silicic acid with organic groups on the surface,
7-strand surfactants, etc. ■ Fillers (Improves image surface gloss, reduces raw material costs) Examples: Calcium carbonate, clay, talc, pigments, etc. In addition to these materials, they also prevent heat from forming on the image surface and toner scattering. In order to prevent this, a small amount of magnetic powder may be included. As such magnetic powders, triiron tetroxide, γ-ferric oxide, chromium dioxide, nickel 7-erite, iron alloy powder, etc. with a grain size of 0.1 to 1 mm are used, and the powder is 0.1 to 5 wt%. Contains. In order to maintain even clearer colors, it is desirable that the content be 1 wt% or less. In addition, resins suitable for pressure fixing toner that is plastically deformed and fixed to paper with a force of about 20 kg/am include wax, polyolefins, ethylene-vinyl acetate co-i1 combination,
Adhesive resins such as polyurethane and rubber are 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 approximately 50 μm or less, especially 15 μm.
It is desirable that it be ~1μ+a. If it exceeds 15 μm, the image quality will be poor, especially if it exceeds 50 μm, it will be difficult to read fine print, and if it is less than 1 μm, fog will occur and the sharpness of the image will be lost. Note that the particle size or average particle size of toner and carrier in the present invention means a weight average particle size, and the weight average particle size is a value measured with a Coulter counter (Coulter Co., Ltd.!!). The specific resistance of particles is 0.
After being placed in a container with a cross-sectional area of 50 cm' and tapped, a load of 1 kg/cu' was applied on the packed particles to a thickness of about 1+am, and a distance of 102 to 10' was placed between the load and the bottom electrode. It is determined from the current value that flows when an electric field of V/ctfi 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 diameter of 50 μm or less, particularly 5 μm or more and 30 μm or less. Preferably. Here, if the carrier particle diameter exceeds 30 μm, especially 50 μm, thinning of the developer layer is inhibited, developability deteriorates, and image quality deteriorates. Also, if the ring is less than 5μ, the developability of the developer, triboelectric chargeability,
Fluidity is poor and carrier scattering occurs. 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 108Ωe.
An insulating material having an insulation resistance of 111 or more, preferably 10+3 ΩC- or more, more preferably 1014 Ωell1 or more is preferable. Such a carrier is made by coating the surface of a magnetic material with a resin, or by dispersing and containing fine magnetic particles in a resin, and selecting the resulting particles using a known particle size selection means. Further, to make the carrier spherical, proceed as follows. ■Resin-coated carrier: Select spherical magnetic particles. ■ Magnetic Powder Dispersion Carrier After forming the bi-dispersed resin, spherical treatment is performed using hot air or hot water, or a spherical dispersed resin is directly formed by spray drying. It is preferable that the above-mentioned toner and carrier be mixed 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 10μIn and the average particle size of the carrier is 20μIn, the toner concentration (weight ratio of toner to developer) is 5 to 40u+t%, preferably 1
It is appropriate to set it to 0 to 25 wt%. That is, in the developer of the present invention, unlike a conventional developer in which toner is attached to a large number of small particles on the outer periphery of a large particle carrier, the particle size of the carrier is small and is close to the particle size of the toner. Therefore, it is preferable that the mixing ratio be such that the total surface area of both materials is approximately equal.

[Example 1] The present invention will be explained in detail with reference to Examples below. Figure t53 (c) shows the structure of the image forming apparatus used. The image input unit IN includes an illumination light source 1, a mirror 22, and a lens Z.
3. The -dimensional color CCD image sensor 24 is integrated into a unit, and the image input section IN moves in the direction of arrow X by a drive device (not shown), and the CCD image sensor 24
reads the manuscript. 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 section IN is sent to the image processing section T.
R is used to convert the data into data suitable for recording. The laser optical system 26 forms a latent image on the image forming body 20 in the following manner based on the above image data, 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, image exposure according to the recorded data from the laser optical system 26 is applied to the image forming body 2 through the lens.
0 is irradiated. In this way, an electrostatic latent image is formed. This e-electronic latent image is developed by a developing device A containing yellow toner. The image forming body 20 on which the toner image has been formed is uniformly charged again by the scorotron charging electrode 27 and subjected to image exposure according to recorded data of another color component. 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 magenta 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. All of B, C, and D have the same structure as the developing device shown in FIG. The multicolor toner image obtained in this way is transferred to the exposure lamp 2.
8, the transfer pole 29
The image is transferred onto the recording paper P. The recording 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 neutralized! It is cleaned by the lR32 and the cleaning device 33. The cleaning device 33 includes cleaning blades 34 and 7.
It has a hoop 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 20 and scrape off residual toner after transfer. After that, the cleaning blade 34 separates from the image forming body 20, and a little later, the 7-hoo brush 35 separates from the image forming body 20. , the fur brush 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 a roller that collects the toner /φ' - scraped off by the blade 34. The laser optical system 26 is shown in FIG. 3(d). In the figure, 37
is a semiconductor laser oscillator, 38 is a rotating polygon mirror, 39 is r
It is a θ lens. In addition, in such an image forming apparatus, in order to align each image, it is effective to place an optical T mark on the photoreceptor and read it with an optical sensor to determine the timing for starting image exposure. be. The image forming process in the copying apparatus shown in FIG. 3(C) involves development using a reversal development method as shown in FIG. Image formation is performed according to the operation timing shown in FIG. (High level indicates the operating state6 in Figure 4) (Developer formulation) Toner composition: Polystyrene 45 parts polymethyl methacrylate 44 Vari 7 Earth 0.2 (Charge control agent) Coloring agent 10.5 #Magnetite powder 0,3 However, the coloring agents used are auramine for the yellow toner, rhodamine for the magenta toner, B1 for the magenta toner, so-called 7-talocyanine 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 methacrylic) (1:1) copolymerized tHN 30 parts by weight magnetite powder 70 Mix the above compositions,
After grinding and classification, a spherical carrier is obtained by hot air treatment. Next, 80 parts by weight of the carrier and 20 parts by weight of toner are sufficiently stirred and mixed to obtain a developer. Table fjS1 Table 4 Table 12 Table 3 The organic photosensitive layer in Table fjS1 has a carrier generation layer containing a trisazo pigment as the lower layer and a carrier transport layer containing an aromatic amino compound as the 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 the timing chart of FIG. 4, the horizontal axis represents one image forming process, and the vertical axis represents each image forming section. Also ^, 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 pseudo halftones due to dots was obtained. Furthermore, scattering of toner and carrier could also be minimized. (Example 2) Next, the toner composition Paris 7 Fust was made 0.4 weight,
Multicolor images were formed in the same manner as in Example 1, except that the image forming conditions were as shown in Tables 5 to 8. [Below] When a multicolor image was formed under the conditions described above in Table 5, Table 8, Table 6, Table 7, it was found that, as in Example 1, a high resolution and good image was obtained without scattering of toner and carrier. A reproduced image with good color tone and gradation reproducibility was obtained. Effects of the Invention As is clear from the above description, according to the developing method of the present invention, resolution, color tone, and gradation can be improved without causing scattering of carrier or toner, mixing of different color toner, leakage discharge from the sleeve, etc. It has excellent reproducibility, can provide clear multi-color images without fogging, and uses a small sleeve for non-contact development, making it possible to use Riki-Kuji Vcr! Effects such as achieving compactness of 1.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a developing device suitable for the developing method of the present invention;
Figure 2 (a) is an optical illusion diagram of the stirring member, Figure 2 (b) 1! ,
A front view of the stirring member, FIG. 13(C) is a cross-sectional view of the main parts of the copying device of the embodiment, FIG. 3(D) is a cross-sectional view of the laser optical system,
FIG. 4 is a diagram showing the operation timing of image formation in the embodiment. FIG. 5 also represents image formation 70-chat. 1.20... Image forming body (photoreceptor) 3... Developer transport carrier sleeve) 4... Magnetic roll 5... Thin layer forming member, 7, 8... Stirring member 7
a, 71], 7c, 8a, 8b, 8c... stirring blade 1
DESCRIPTION OF SYMBOLS 1... Toner supply container, 14... Developing bias 15... Developing area, rt... Image manual department 2
4...Image sensor, 26...Laser optical system^, B, C, D...Developing device, 28...Exposure lamp 29...Transfer pole, 30...Separation pole 31... Fixing device, TR...Image processing unit 33...Cleaning device Applicant: Roku Konishi Photo Industry Co., Ltd. Figure 1 Figure 2 (A) Figure 2 (0) Figure 3 (...) Figure 3 ( =)

Claims (5)

[Claims] (1) By forming a thin layer of a two-component developer consisting of a carrier and a toner on a plurality of developer conveying bodies and developing a latent image on an image forming body with at least one thin layer, the process is performed multiple times. A developing method comprising forming a multicolor toner image on the image forming body. (2) The developing method according to claim 1, wherein the carrier has an average particle size of 30 μm or less. (3) The developing method according to claim 1 or 2, wherein the thin layer of the developer has a thickness of 300 μm or less. (4) Claim 1, wherein the thin layer of the developer is held on the developer transporting member so as not to contact the image forming body.
Developing method according to items 3 to 3. (5) The developing method according to any one of claims 1 to 4, wherein an electrical and/or magnetic bias having a vibrational component is applied to the thin layer of developer.