JPS6334571A - Copying method - Google Patents

Abstract

PURPOSE:To permit faithful reproduction of a high-quality image on an original by transferring the toner image obtd. by development with a conductive toner non-electrostatically to an intermediate transfer medium, then pressing the same via a recording sheet interposed thereto by a heating roll, thereby transferring and fixing the image to the recording sheet. CONSTITUTION:The toner image of <=20mu thickness obtd. by subjecting a photosensitive belt 1 to uniform electric charging, then to image exposure to form an electrostatic latent image and developing said image with the conductive toner is once non-electrostatically and primarily transferred to the intermediate transfer medium 2 by a press roll 13. The primarily transferred image is then secondarily transferred and fixed onto the recording sheet 3 by using the heating roll 15 to form the permanent image. The surface roughness of the recording medium is specified to <=1 cycle/mm frequency of ruggedness having >=0.5mu depth and <=1mu depth and the surface roughness of the intermediate transfer medium is specified to <=2 cycles/mm frequency of ruggedness having >=0.5mu depth and <=3mu depth. The high-quality final image is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming a backward image such as electrophotography or electrostatic recording. More specifically, the present invention relates to a copying method that uses an intermediate transfer member to perform two transfer steps to obtain high-quality images.

[Prior Art] In an electrophotographic method, a photoconductive layer formed on a conductive substrate is uniformly charged, and then the charge is removed imagewise by an exposure operation to form an electrostatic latent image.

This latent image is made visible with a colored resin called toner. This visualized developed image is transferred to a transfer paper such as paper by electrostatic attraction, and then melted and fixed onto the transfer paper via a fixing roll to obtain a permanent image.

In the transfer process, a corotron or a roll to which a bias is applied is generally used.

In such reproduction methods, it is known that the quality of the final fixed image is often degraded due to image disturbance during the transfer process.

In view of this point, 12 copying methods that omit the electrostatic transfer step have been proposed.

For example, Japanese Patent Publication No. 37-11646 discloses a method in which a toner image formed on a photoreceptor is directly superimposed on a transfer paper and then transferred and fixed using a heating roll or the like.

Furthermore, in Japanese Patent Publication No. 46-41679, an intermediate transfer medium made of silicone rubber or the like is used to non-electrostatically transfer a toner image formed on a photoreceptor to the intermediate transfer medium.
A copying method is disclosed in which a toner image on the intermediate transfer medium is simultaneously transferred and fixed to the transfer paper by bringing an intermediate transfer medium into contact with a heating roll via a transfer paper.

Furthermore, Japanese Patent Publication No. 48-22763 discloses a thermal transfer fixing method that combines a conductive magnetic toner and a silicone rubber intermediate transfer medium.

Further, JP-A-56-138742 discloses a thermal transfer fixing method using a charge retention layer made of a heat-resistant resin and an intermediate transfer medium such as silicone rubber.

These copying methods started with the aim of simplifying the process, but gradually improved the quality of copied images and
In other words, in conventional copying methods that utilize electrostatic force using corotrons, etc., disturbances occur in the toner image on the transfer paper.
This method has been attracting attention as a means for avoiding defects that cause disturbances around line images, reduction in resolution, and reduction in graininess of solid images in the final fixed image.

[Problems to be Solved by the Invention] In the prior art, an attempt has been made to improve the quality of copied images by simply using non-electrostatic means for the transfer process. Through a series of processes including latent image formation, development, transfer, and fixing, high-quality images, especially halftone images of 100 to 200 lines/inch, can be reproduced faithfully to the original without losing gradation. The objective is to provide a copying method that is possible.

[Means for Solving the Problems] The present invention involves a step of forming an electrostatic latent image faithful to an original on a recording medium with a smooth surface, and forming the electrostatic latent image into a uniform thin layer using conductive toner. A step of developing, a step of non-electrostatically transferring the obtained toner image to an intermediate transfer medium with a smooth surface, and a step of pressing the toner image on the intermediate transfer medium with a heating roll with a recording sheet interposed therebetween to form a recording sheet. The present invention provides a copying method comprising a step of transferring and fixing.

As shown in FIG. 1, in the copying method of the present invention, for example, a photoreceptor belt 1 is first uniformly charged with a corotron, and a first
(a)), then imagewise exposure is performed to form an electrostatic latent image (FIG. 1(b)), and this electrostatic latent image is developed with a high resistance toner (FIG. 1(C)), and the resulting toner is The image is first transferred to the intermediate transfer medium 2 non-electrostatically using the pressure roll 13 (FIG. 1(d)), and then the primary transfer image is secondarily transferred and fixed onto the recording sheet 3 using the heating roll 15. A permanent image is formed (FIG. 1(e)).

The present invention will now be described in detail with reference to an example of a copying system implementing the method of the present invention shown in FIG.

(1) Step of forming a latent image After the photoreceptor is uniformly charged, it is imagewise exposed to form an electrostatic latent image. In the system shown in FIG. 2, a latent image is formed by exposure 5 after the belt-shaped photoreceptor 1 moving in the direction a is charged by a charger 4.

The photoreceptor does not necessarily have to be belt-shaped; a drum-shaped one can also be used.

As the material for the photoreceptor, Se is used as an inorganic amorphous material.
, Se/As, As2 Se3 , Se/Te, Si,
S, CdS, CdSe, 7nO, Ti as crystalline materials
A material comprising a charge generating material such as O2, an organic bisazo pigment, a phthalocyanine pigment, or a squareium pigment, and a charge transporting material such as an aromatic amine or hydrazone can be used.

The characteristics required for a photoconductor to obtain high-quality copied images are photoreceptor, surface shape, PIDC
uced Decay Curve >Characteristics, surface resistance.

Regarding the surface shape, for example, in a dispersion-type photoreceptor such as ZnO, the surface roughness is rough with a frequency of 5 cycles/mm and a depth of 7μ with unevenness of 0.5μ or more, and a toner image is formed on the photoreceptor. In this case, toner particles enter the recesses, and during the primary transfer to the intermediate transfer medium, the toner particles embedded in the recesses of the photoreceptor not only cause blurring of the image transferred to the intermediate transfer medium, but also cause the image to be transferred to the intermediate transfer medium. Cleaning also creates a load.

Vapor-deposited photoreceptors such as 3e type photoreceptors have very good primary transfer characteristics, but even dispersion type photoreceptors such as ZnO can have good primary transfer characteristics by smoothing the surface. I can do that.

Experimentally, the frequency of irregularities with a surface roughness of 0.5μ or more in depth is 1 cycle/m or less, and when the depth is 1μ or less, the frequency is approximately 1.
It was confirmed that 0.00% primary transfer could be achieved.

Regarding the PIDC characteristic, a steep one, that is, a binary characteristic is preferable, especially for halftone dot reproduction.

PIDC characteristics (sensimetry) is the amount of exposure to the photoreceptor,
Adjustment is possible by controlling the charging potential, etc.

Regarding the surface resistance, it is preferable to form a dielectric film or an insulating film by spray coating on the photoconductive layer, particularly in order to suppress leakage of latent image charges due to entanglement with the developer. It is also possible to mix conductive metal fine powder into the film to control its resistance.

In addition, from the viewpoint of heat resistance, a-3i is preferable, and similarly inorganic photoconductive materials such as CdS, Cd53e,
Cd3e, Zn5e, ZnCd5, TiO2, Zn0X
CdS-CdCO3 dispersed in a heat-resistant resin can be used. Heat-resistant resins include fluorine resins, polyimide resins, polyamide resins, polyimide amide resins, polyarylsulfone resins, polyphenylene sulfide resins, thermosetting acrylic resins, thermosetting alkyd resins, epoxy resins, and mixtures thereof. A material widely used as a heat-resistant resin in the field is used.

Specific examples of these heat-resistant resins include polytetrafluoroethylene, tetrafluoroethylene-6-
Propylene fluoride copolymer, poly(ethylene chloride trifluoride), polyvinylidene fluoride, ethylene chloride trifluoride-vinylidene fluoride copolymer, poly-perfluoroalkylene (PP8), polyhinylheptafluorobutylene Rateamidine (nylon 6), Seidel (nylon 66), Kapton (polyimide resin), Rydon pps
Examples include v-i type [polyphenylene sulfide resin, manufactured by Idogatani Kagaku U] and Astrelu 560 [boaryaryl sulfone resin, manufactured by 3M Company]. Among the heat-resistant resins mentioned above, fluororesins, polyimide resins, polyamide resins, polyimide amide resins, polyphenylene sulfide resins, or mixtures thereof are preferred.

In the process of forming a latent image, contact transmission exposure using a transparent original is preferable, but it is restricted by the complexity of creating the original, the need for suction equipment to increase contact accuracy, and the complexity and size of the equipment. . In practical terms, tracking error,
In order to suppress velocity errors and the like, it is preferable to use a belt-shaped photoreceptor and perform static exposure using a flat surface or exposure in a state where the relative position with respect to the original can be considered unchanged.

When considering high speed, flash exposure using a belt-shaped photoreceptor is particularly suitable.

(2) Developing process After forming a faithful latent image on the original, toner development is performed by the developer Ia6.

In this development process, the image spreads in the primary process of transfer,
It is essential to take uniform development into a thin layer in consideration of crushing.

In particular, the height of the toner image (pile hide) is more important than the toner particle size, and experimentally the range of 10 to 20μ is the spread of line images, and in the case of halftone images, the spread of dots from highlights to shadows. We found that it is possible to suppress the collapse.

As a specific method for developing the uniform thin layer, conductive component toners yield good results.

The electrical resistance value of toner is experimentally 103v/
It was confirmed that 10 3 to 10 11 Ω” cm is preferable in an electric field of cm.

Although either magnetic or non-magnetic toner can be used, magnetic toner is preferred from the viewpoint of ease of transport and supply, and non-magnetic toner is preferred from the viewpoint of coloring.

In the case of magnetic toner, use a magnetic brush development method or magnetic tape to apply a thin layer of magnetic toner onto the tape.
A developing method that performs step-down or jumping can be applied.

In the case of non-magnetic toner, a method in which a thin metal plate is pressed against a donor roll having a culm of 10 to 1014 Ω·cm to form a thin layer of toner, or an impression method can be applied.

It has been experimentally confirmed that the toner has a particle size (average particle size) of 10 microns or less, preferably 1 to 5 microns.

Considering the particle size of printing ink and liquid developer, it is important to improve image quality (particularly graininess of low-density solid images, improvement of resolution, dot shape of halftone images, and improvement of DmilX). Although very good results have been achieved, there are limits due to manufacturing constraints and handling.

It is better to have a narrower particle size in consideration of the selection image, or the transfer during the next transfer or secondary transfer (that is, it is desirable that the pressing force acts uniformly on each toner particle), and the experimental The distribution index dqo/d.

It was found that 2 to 4 gave good results.

The toner material is used to prevent offset to the photoconductor during secondary transfer, and to prevent offset to intermediate transfer medium during secondary transfer.
From this point of view, a release agent may be added to the toner.

This mold release agent may be one that imparts mold release properties to the toner binding resin, or may be added as a mold release agent.

Examples of resins for toners that have releasable properties include polymers of styrene-based intermediates, vinyl mono-omega polymers, or styrene-based intermediates and other vinyl monomers. Examples include copolymers with

Examples of styrenic intermediates include styrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, p-0-hexylstyrene, and p-methylstyrene. ] to styrene and its derivatives such as xystyrene, p-phenylstyrene, and 3,4-dichlorostyrene, and styrene monomers are most preferred. As Haku's vinyl monomers,
For example, ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride and vinylidene chloride; vinyl esters such as vinyl acetate, vinyl benzoate, and vinyl acetate; methyl acrylate, and acrylic Ethyl acid, isobutyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethyl methacrylate α-methylene aliphatic monocarboxylic acid esters such as ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylamine ethyl methacrylate, and diebruaminoethyl methacrylate; acrylic acid or methacrylic acid such as acrylonitrile and acrylamide Examples include rti derivatives; vinyl ethers such as vinyl ethyl ether; vinyl ketones such as vinyl methylbutone; N-vinyl compounds such as N-vinylpyrrole and N-vinylcarbazole; and vinylnaphthalenes.

Specific examples of copolymers include styrene-vinyl acetate copolymer, styrene-methyl methacrylate copolymer, styrene-methyl acrylate copolymer, styrene-2-ethylhexyl methacrylate copolymer, and styrene-acrylic acid 2 copolymer.
-chloroethyl copolymer or styrene-phenyl methacrylate copolymer. These polymers have a weight average molecular weight of 3,000 or more, preferably 3.
It is preferable to have a molecular weight of 000 to 500,000.

It is generally preferred that these polymers have a weight average molecular weight ffi/vl average molecular weight average molecular salt.

Examples of the mold release agent as an additive include low molecular weight olefin polymers, metal salts of fatty acids, higher fatty acids, fatty acid amides, higher alcohols, hydrocarbon lubricants, and fatty acid esters.

The low molecular weight olefin polymer used in the developer of the present invention is an olefin monopolymer containing only an olefin as a monomer component or an olefin copolymer containing a monomer other than olefin as a monomer component. It is a low-molecular substance.

Olefins as monomer components include, for example, ethylene, propylene, butene-1, octene-1 or their hX forms with different positions of unsaturated bonds, or, for example, 3-methyl-1-butene, 3- All kinds of olefins such as propyl-5-methyl-2-hexene and the like having an alkyl group introduced as a branched chain are included.

In addition, examples of monomers other than olefins that form copolymers with olefins include vinyl ethers such as vinyl methyl ether and vinyl phenyl ether, vinyl esters such as vinyl acetate, tetrachloroethylene, chloride, etc. Haloolefins such as vinyl, vinylidene chloride, and tetrachloroethylene, such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, rho-1-tyl methacrylate, stearyl methacrylate, and methacrylic! Acrylic acid esters or methacrylic acid esters such as N,N-dimethylaminoethyl and methacrylic lt-butylaminoethyl; for example, acryl[]nitrile; acrylic type derivatives such as N,N-dimethylacrylamide; for example, acrylic acid; Various organic acids such as methacrylic acid, diethyl fumare-1., and β-pinene can be mentioned.

Low molecular weight olefin polymers are olefin polymers consisting only of olefins containing at least two of the above-mentioned olefins as monomer components, such as ethylene-propylene copolymers, ethylene-butene copolymers,
Ethylene-pentene copolymer, propylene-butene copolymer, propylene-pentene copolymer, ethylene-3-
Methyl-1-butene copolymer, ethylene-propylene
An olefin copolymer, such as ethylene-vinyl acetate, containing as a monomer component at least one of the above-mentioned olefins and at least one monomer other than the above-mentioned olefins. polymer, ethylene-hinyl methyl ether copolymer, ethylene-vinyl chloride copolymer, T-tyrene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer,
Ethylene-acrylic acid copolymer, propylene-M! Vinyl copolymer, propylene-vinylethyl ether copolymer, propylene-ethyl acrylate copolymer, propylene-methacrylate copolymer, butene-methyl methacrylate copolymer, pentene-vinyl acetate copolymer, Hexene-vinyl acetate copolymer, ethylene-propylene-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl methyl ether copolymer, etc.

Among low-molecular-weight olefin polymers that contain monomers other than olefins as monomer components, it is desirable that the copolymer contain as many olefin components as possible. This is because, in general, the smaller the content of the olefin component, the lower the releasability, and the lower the fluidity of the toner.
This is because characteristics such as image quality tend to deteriorate.

For this reason, it is desirable that the content of the olefin component in the copolymer be as large as possible, and in particular, a copolymer containing about 50 mol% or more of the olefin component is effectively used.

The molecular weight of the low molecular weight olefin polymer may be anything that is included in the concept of low molecular weight in ordinary polymer compounds, but it is generally a quick average molecular weight of 1.000 to 45,00.
0. Preferably it is 2,000 to 6,000.

Low molecular weight olefin polymers have a softening point of 100-180'
C, especially those having a temperature of 130 to 160°C are preferred.

The amount of the low molecular weight olefin polymer used is 1 to 20 parts by weight, preferably 3 to 15 parts by weight, per 100 parts by weight of the resin component of the toner, and if it is less than 1 part by weight, it may not have a sufficient effect of imparting release properties. If the amount is more than 20 parts by weight, it may tend to deteriorate other properties of the toner, which is not preferable.

Other examples of release agents used in the developer of the present invention include:
Metal salts of fatty acids include lead, zinc, magnesium, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid, oleic acid, caprylic acid, cyproproic acid, linoleic acid, ricinoleic acid or ricylic acid, Examples include metal salts of cobalt, copper, calcium, cadmium, iron, nickel, aluminum or barium; higher fatty acids include decanoic acid, which usually has 8 or more carbon atoms;
Examples include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid or ricinoleic acid; fatty acid amides such as lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, arachidic acid amide, behenic acid Amide, oleic acid amide, linoleic acid amide, linoleic acid amide, gadolenic acid amide, erucic acid amide, ceracoleic acid amide: As bis fatty acid amide, bislauric acid amide, hismyristic acid amide, hispalmitic acid amide, bisstearic acid amide , N,N'-cytodecanoyl-ethylenediamine; higher alcohols include lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, and oleyl alcohol; fatty acid esters include esters of fatty acids and monohydric alcohols; Examples include full or partial esters of fatty acids and polyhydric alcohols, and hydrocarbon lubricants include natural paraffins, synthetic paraffins, microwaxes, and chlorinated paraffins.

The amount of these release agents added to the developer is 0.1 to 65% by weight, preferably 0.2 to 20% by weight based on the developer.
Weight%.

General developer additives and manufacturing methods will be described below.

In addition to containing the above-mentioned release agent, the toner also contains a binder resin for toner. These resins may have the above-mentioned mold releasability, or may not have mold releasability, such as epoxy resins, polyester resins, and polyamide resins.

Any coloring agent such as a pigment or dye can be added to the toner according to the present invention, if necessary. These coloring agents are known ones, such as carbon black, nigrosine dye, aniline blue, carfoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green ogyza. black, lamp black, oil black, azo oil black, rose pencal and mixtures thereof. Also, where conventional xerographic reproduction of printed documents is desired, the toner may be made from a black dye, such as a black dye such as carbon black or an amaplast black dye.

The amount of the colorant used in the toner of the present invention can be widely adopted, but it is usually 1 to 20 parts by weight based on 100 parts by weight of the toner binder resin.

When the toner is used as a one-component imaging agent, an arbitrary magnetic material may be added thereto.

The magnetic material that can be used is a material that is strongly magnetized in the direction of a magnetic field, preferably black in color, well dispersed in one unit/one fat, chemically stable, and with a particle size of 1μ or less. It is desirable that the material be easily obtained in the form of fine particles, and magnetite (triiron tetroxide) is the most preferred.

Typical magnetic or magnetizable materials include cobalt,
Metals like iron, nickel, aluminum, cobalt,
Alloys and mixtures of metals such as copper, iron, lead, magnesium, nickel, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, mankan, selenium, titanium, tungsten, vanadium; aluminum oxide, iron oxide, oxide copper, nickel oxide, annealed oxide),
Metal compounds including metal oxides such as butane oxide and magnesium oxide; refractory nitrides such as vanadium nitride, chromium nitride; carbides such as tungsten carbide and silica carbide; ferrites and mixtures thereof are used. . These ferromagnetic materials preferably have an average particle size of about 0.1 to 1 μm, and the amount of ferromagnetic material contained in the toner is preferably about 50 to 500 parts by weight per 100 parts by weight of the adhesive resin component for toner. , particularly preferably resin component 100
It is 80 to 200 times lower than the heavy early part.

Other charge control agents, fluidizing agents, etc. may be added to the toner as appropriate.

The toner is manufactured by any manufacturing method such as the so-called kneading method and polymerization method.

The kneading method is a method of manufacturing by mixing, for example, a binder resin for toner, a mold release agent, a coloring agent, a charge control agent, a magnetic material, etc., melting the mixture, cooling it, and pulverizing it.

On the other hand, the polymerization method is a method in which a release agent, a colorant, a charge control agent, a magnetic material, etc. are mixed with a 11-mer binder resin for toner, and a toner is produced all at once by, for example, suspension polymerization.

(3)-Next transfer process The toner image on the photoreceptor belt is then transferred to the intermediate transfer medium 2 moving in the b direction by a non-electrostatic method, i.e. by the support roll 12.
The primary transfer is performed by passing the photoreceptor belt and the intermediate transfer belt overlappingly between the press roll 13 and the press roll 13 .

The intermediate transfer medium used in this -next transfer has the following characteristics: -next transfer, transfer rate in the secondary transfer, omission of image areas (toner particles enter the recesses of the intermediate transfer medium in the primary transfer, The contact area will be insufficient and will appear white on the final image.

In the case of a halftone image, this phenomenon lowers the DIIlax of the dots and causes a loss of gradation. ), and considering the ease of cleaning the intermediate transfer medium, the smoothness of its surface is important.

Experiments have shown that the surface roughness of the intermediate transfer medium or the depth of 0.5
Frequency of unevenness of μ or more: 2 cycles/m or less, depth: 3μ
It was found that the following gave good results.

As an intermediate transfer medium having such a rough surface, a heat-resistant resin film with layers of various elastomers or rubber materials is used. Specific examples of the surface layer include TSE387RTV and TSE3 manufactured by Toshiba Silicone 1.
88W, TSE389C (trade name), manufactured by Shin-Etsu Chemical Co., Ltd., KI? 271. KR272, KE 130. E136-V, KE12RrV.

E17RTV, E/12RTV, KE113RTV
, KF1800ABCRTV, etc. (all above product names), manufactured by Toshi Silicone Co., Ltd., Sl+-780, 5E9140.3
8850, 5H748V, 5RX475V, 5H16
03V etc. (hereinafter referred to as product name), manufactured by Bayer (7) EVW
-1018, EV-1840, etc. (trade names on LX), Coronate C-4046, Niraporan 4038, etc. (trade names listed above) manufactured by Nippon Polyurethane Co., Ltd., and the like.

Furthermore, carbon black or metal powder may be dispersed for the purpose of preventing static electricity.

In the primary transfer step, the transfer is performed non-electrostatically, and the intermediate transfer medium is neutralized by a static eliminator 1 before the transfer.

(4) Secondary transfer fixing step Next, the primary transfer toner image is heated and fixed with the transfer paper 3 moving in the C direction interposed. [1-Rule 15 is pressed against the support roll 14 to transfer and fix the image.

In this transfer fixing process, the toner image on the intermediate transfer medium is heated by a preheater 9, and the transfer paper is also heated by a preheater 16.

The intermediate transfer medium after the secondary transfer and fixing is cleaned by a cleaning device 10.
is cleaned and prepared for the next cycle.

Further, the photoreceptor belt after the next transfer is also cleaned by the cleaning device 8 after being neutralized by the static eliminator 7, and then transferred to the next close-up recycle.

[Example] The present invention will be described below with reference to Examples and Comparative Examples.

The example photoreceptor was a Se-based photoreceptor (surface roughness or depth of 0.5 μm).
Above unevenness frequency 1 cycle/m, depth 0.5μ: 5
TAK [measured by LOAN Kano], Fuji Photo Film Co., Ltd.'s electrostatic printing master "ELP280" as the exposure system,
-component magnetic toner (d50=
4.8μ, d9o/d, o=3.5. Resistivity: 10
A magnetic brush development method was adopted using a toner disk (2X103Ωcm) created with an electric field of 3V/cm and 1.4Nff/-, and silicone RTV (manufactured by Shin-Etsu Chemical Co., Ltd., thickness 100μ, Concave and convex frequency 1CVC1e/cocoon with surface roughness of depth 0.5μ or more,
When a copying test was carried out using a 2.5μ depth) and a surface temperature of the h0 heat fixing roll of 180' (1:1), a high quality copy image with excellent gradation reproducibility of halftone originals was obtained. Ta.

A ZnO-based photoreceptor (surface roughness: 0.5 in depth) was used as a comparative example photoreceptor.
Concave and convex frequency of μ or more 6 Cycl e/m, depth 8μ
:〉, lens mirror scan method (roK
o)IAsTERFAX) When a copying test was conducted using the same developing conditions, primary transfer, and secondary transfer fixing conditions as in the example, it was observed that some shadows of the halftone original were soaked, and The maximum image density (DmaX) was low, and the image had a soft overall feel.

FIG. 3 shows the gradation (relationship between original density of 175 lines/inch and copy image temperature) in halftone images of Examples and Comparative Examples.

[Effects of the Invention] The present invention relates to a copying method in which a toner image is first transferred non-electrostatically using an intermediate transfer medium, and then transferred and fixed onto a recording paper. developing,
- A novel copying method is provided which is capable of producing a high quality final image by combining a series of processes of secondary transfer and secondary transfer and fixing.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the image forming process in the copying method of the present invention, FIG. 2 is a schematic diagram of an example of a system implementing the copying method of the present invention, and FIG. 3 is a diagram showing line point reproduction in the example and comparative example. It is a graph showing gradation. Symbols in the figure: 1... Photoreceptor belt; 2... Intermediate transfer belt: 3
...Transfer paper: 4...Charger; 5...Exposure: 6
...Developer near, 11...Static eliminator: 8.10...
Cleaning device; 9... Tofu preheater: 12° 14... Support roll: 13... Press roll; 15
...IJ11 heat roll; 16...transfer paper preheater;
a, b, c...Movement direction. Figure 1 ((1) Figure 1 (b) Figure 1 (C) Figure 1 (d) Figure 1 (e) Figure 2

Claims (1)

[Claims] 1) A step of forming an electrostatic latent image faithful to the original on a recording medium with a smooth surface, a step of developing the electrostatic latent image in a uniform thin layer with conductive toner, The toner image is transferred non-electrostatically to an intermediate transfer medium with a smooth surface, and the toner image on the intermediate transfer medium is transferred and fixed onto the recording sheet by being pressed with a heating roll with a recording sheet interposed. A copying method characterized by: 2) The copying method according to claim 1, wherein the surface roughness of the recording medium is such that the frequency of irregularities of 0.5 μm or more in depth is 1 cycle/m or less and the depth is 1 μm or less. 3) The copying method according to claim 1, wherein the thickness of the toner layer formed on the recording medium in the developing step is 20 μm or less. 4) The copying method according to claim 1, wherein the surface roughness of the intermediate transfer medium is such that the frequency of irregularities of 0.5 μm or more in depth is 2 cycles/mm or less and the depth is 3 μm or less.