JPH0281A - Developing method - Google Patents

Abstract

PURPOSE:To develop an electrostatic latent image in alternating magnetic fields and to obtain the image having high sharpness by allowing a developer having colored particles which contain a magnetic material and colored particles which have the charge polarity different from the charge polarity thereof and do not contain the magnetic material to exist on a developer transporting material contg. a magnet body. CONSTITUTION:Polyethylene terephthalate having Al on the rear surface is used and the electrostatic latent image 4 of prescribed positive and negative voltages is developed with the composite developer the positive polarity of which is red and the negative polarity is black by a developing device. The development is executed by impressing, for example, 1kV, 500Hz AC to the developer layer of a prescribed value while feeding said layer to the developing region in the spacing of a photosensitive body sleeve 5-a maintained at the prescribed value. The composite developer is charged by a corona charger 6 and is unified to the negative polarity. The charged developer is transferred by a corona charger 8 for transfer to recording paper 8 and is heated and fixed by a heater 9 for fixing, by which the image is recorded. The recorded image which is free from fogging and color clouding and has the high sharpness is obtd. on plain paper at a high speed by unifying the polarities of the developer to one polarity by the corona charge and transferring the developed image to the recording paper in such a manner.

Description

[Detailed description of the invention] The present invention relates to a method for developing an electrostatic latent image.

A typical example of representing an electrostatic latent image as a multicolor image is a color image using an electrophotographic method. In this conventional method, the original document is passed through an optical filter to separate the colors, and the separated light is used to carry out the charging, exposure, development, and transfer processes using yellow, magenta, cyan, and black colored particles. This is done by repeating it four times. There is also a so-called two-color development method in which electrostatic latent images of different polarities are formed on the same photoreceptor and developed with black and red colored particles. Although these methods of forming multicolor images are desirable because they can add color information compared to the information obtained from monochrome images, they have the following problems.

(1) Since it is necessary to use a developing device for each color, the machine becomes large and the cost increases.

(2) It is necessary to guarantee color shift accuracy through repeated operations.

(3) - Copying time becomes longer.

For these reasons, attempts have been made to miniaturize the developing device by mixing two different colored developers in the same developing device (for example, Japanese Patent Publication No. 55-3062).
However, simply mixing two different colored developers causes the following drawbacks.

(1) Development occurs even in areas where there is no electrostatic latent image, and so-called fogging is likely to occur.

(2) Because other developers are mixed into the developed image, the color is poor (color turbidity is likely to occur).

(3) Sharp images cannot be obtained.

An object of the present invention is to provide an electrostatic image developing method in which fog does not occur when developers having different charging polarities are used.

Another object of the present invention is to provide an electrostatic image developing method that does not cause color clouding when developers having different charging polarities are used.

Still another object of the present invention is to provide an electrostatic image developing method that allows sharp images to be obtained when developers having different charging polarities are used.

The above aspects of the present invention include colored particles containing a magnetic substance;
A developer having colored particles having a charge polarity different from that of the colored particles and not containing a magnetic substance is placed on a developer transporting member containing a built-in magnet, and an image is formed in a developing area to which an alternating electric field is applied. This is achieved by a developing method adapted to develop an electrostatic latent image on a support.

In the developing method of the present invention, when an alternating electric field is applied during development, development of colored particles of other charged polarities can be prevented,
Particularly sharp images can be obtained.

Figure 1 shows the relationship between the potential of an electrostatic latent image and the amount of developer contributing to development, with the horizontal axis representing the potential and the vertical axis representing the amount of developer.
In the figure, the vertical axis output shows the amount of negatively charged developer, the lower part shows the amount of positively charged developer, the right side of the horizontal axis shows the positive potential, and the left side shows the negative potential. In FIG. 1, A is a curve shown by a negatively charged developer that does not contain a magnetic material, B is a curve shown by a positively charged developer that does not contain a magnetic material, and the shaded areas C and D are the range of fog that has occurred. It shows. In FIG. 1, in order to remove the generated fog, a method is known in which an electric bias is applied to the image support. However, in this method, developer charged with opposite polarity is deposited by applying an electrical bias.

That is, the generated fog cannot be removed by applying an electrical bias. However, this problem can be solved by applying a magnetic bias to the developer containing the magnetic material by using a developer conveying member containing a magnet.

For example, when developing an electrostatic latent image using a positively charged developer containing a magnetic material under a magnetic bias, the relationship shown in FIG. 1 becomes as shown in FIG. 2.

In FIG. 2, the vertical axis, the horizontal axis, and the curve A are the same curves as in FIG. 1, which are for a negatively charged developer that does not contain a magnetic material, and the curve E is a curve that shows a negatively charged developer that does not contain a magnetic material, which is applied to the present invention. A curve shown by a positively charged developer; in this case, curve E is the first curve.
No fog occurs in the shaded area of curve B shown in the figure, and fog in the shaded area C of curve A can be eliminated by applying an electric bias [VO3.

Furthermore, when a magnetic bias is applied to the developer of the present invention,
That is, when a negatively charged developer shown by curve A in FIG. 2 containing a magnetic material is used, the result is as shown in FIG. 3.

In FIG. 3, the vertical axis, horizontal axis, and curves are the same as in FIG. The fog shown in FIG. 1 does not occur, and the electrical bias used in FIG. 2 can also be dispensed with.

As shown in Figure 3 of A, the colored particles having different polarities and containing magnetic substances (hereinafter referred to as composite developer) contain developer base magnetic substances for positive and negative charging. Therefore, the developer can be reliably tribo-electrified and transported, and from this point of view as well, it is effective in improving image quality. A positive or negative electrostatic latent image may be developed with a composite developer of the same color, but it can also be developed with developers of different colors depending on the polarity of the electrostatic latent image, which allows more information to be developed. The latter developing method is preferable in the present invention because it can contain the above-mentioned components.

In addition, in the development step, development with a unipolar developer may be repeated sequentially, but when developing a bipolar electrostatic latent image, -
It is more efficient to develop with a bipolar developer at the same time.

In the developing method of the present invention, it is preferable to use a normal magnetic brush developing method, but even if fog does not occur, some developer of the opposite polarity may be mixed into the developer attached to the electrostatic latent image. , developer of opposite polarity tends to adhere around the electrostatic latent image.

The difficulty of adhesion of development positions of opposite polarity can be solved by developing with an alternating electric field applied during development.

This developing method is a method in which an electrostatic latent image on an image support and a developer held on a developer conveying member are faced to each other with a gap therebetween, and development is performed under an alternating electric field (for example, in Japanese Patent Laid-Open No. 55-1865,
No. 6, Publication No. 55-18659, U.S. Patent No. 3,8
No. 90,929) or a method of developing under a low frequency alternating electric field in a contact state. These techniques make it possible to reliably attach only the polar developer to be attached to the electrostatic latent image by causing the developer to fly or vibrate.

Developing under an alternating electric field is also effective in sharpening images.

It is preferable that the above-mentioned composite developers are the same except for charging polarity, so that both polarity developers can develop electrostatic latent images of different polarities and to the same extent. These conditions are 5-2
Particle size of 0 μ, charge amount of 0.2 to 20 μc/H,
Examples include having the same magnetization strength and the same dielectric constant.

Next, the developer of the present invention will be explained.

The magnetic material-containing developer used in the present invention is broadly classified into microcapsule developer and powder developer.

The former type of microcapsule developer generally has a core material and an outer synthetic resin film, and at least one of them contains a magnetic material. Particularly preferably, a first wall film mainly composed of a film-forming polymer or substance is provided on the outside of the core material, and further a second wall film containing a magnetic material and mainly composed of a synthetic resin is provided on the outside of the first wall film. This developer is provided with a wall film of No. 2.

Encapsulation methods for microcapsule developers include complex coacervation methods; simple coacervation methods, salt coacervation methods; water-soluble or aqueous dispersion methods such as pH change, solvent change, and insolubilization of polymers by solvent removal. phase separation method; interfacial polymerization method; In5it
U polymerization methods are alkaline, and here we will discuss the complex coacervation method as an example.

A non-aqueous solution or non-aqueous dispersion of a colorant is added to an aqueous solution of a film-forming polymeric substance (for example, gum arabic) adjusted to a predetermined pH (alkaline side), concentration, and temperature, and then dispersed and emulsified. and an aqueous solution of a film-forming polymeric material (eg gelatin) which is a gelatinable isoelectric colloid and is temperature adjusted. Next, the pH of this mixed solution is made acidic to cause phase separation. By doing this, both of the polymeric substances are precipitated around the droplets of the non-aqueous solution or dispersion of the colorant.Then, the liquid is cooled and a hardening agent (formalin) is added to make it alkaline and the temperature of the liquid is increased. is raised to harden the precipitate. Further, at least a magnetic material and a synthetic resin emulsion are added to the obtained capsule liquid, uniformly dispersed, and then spray-dried to obtain the desired developer.

Colorants used in the core material include inorganic pigments, organic pigments, direct dyes, acid dyes, basic dyes, mordants, acid mordant dyes, disperse dyes, and oil-soluble dyes. Specific examples of these include black pigments such as carbon black, acetylene black, lamp black, graphite, mineral black, aniline black, and cyanine black, and yellow pigments such as yellow lead, zinc yellow, barium chromate, cadmium yellow, and lead cyanamide. , calcium leadate, naphthol yellow 8
1 Hansa Yellow 10G.

Hansa Yellow 5G, Hansa Yellow 3G, Hansa Yellow G
1 Hansa Yellow GR, Hansa Yellow G1 Hansa Yellow R
N, Hansa Yellow R1 Pigment Yellow L1 Benzine Niro Benzine Niro 01 Benzine Yellow GR, Permanent Niro-NN0G.

Palkan Fast Yellow 501 Palkan Fast Yellow R1 Tartrazine Lake, Quinoline Yellow Lake, Ansuflow Yellow 6GL, Permanent Niro FGL, Permanent Niro HLOG, Permanent Niro HR
, Anthrapyridine Niroichi, etc. Red pigments include Red Garla, Red Lead, Silver Vermilion, Cadmium Red, Permanent Red 4R, Rose Red, Fire Red, Western Vermilion, Parachlororthonitroaniline Red, Linur 7 Asto Scarlet G, Brilliant Fast Scarlet, brilliant carmine BS1 permanent red F2R, permanent red F4R, permanent red FRL, permanent red, FRL
L.

Permanent Ref FF4RH, Fast Scarlet V
D, Palcan Fastorpine B1 Eosin Lake, Rhodamine Lake, Rhodamine Lake Y1 Alizan Lake,
Thioindigo Red B1 Thioindigo Machine, Permanent Red FGR, PV Carmine HR, etc. Blue pigments include ultramarine, navy blue, cobalt blue alkali blue lake, peacock blue lake, Victoria blue lake, metal-free phthalocyanine blue phthalocyanine blue fast sky blue indance Remble-R51 indane Tremble-BS, indigo, etc., and as a yellow dye, C, 1, (color index) Direct Yellow 98. C, 1, Direct Yellow 89
．． C, 1, Direct Yellow 88 (more than direct dye),
C, 1, acid yellow 1. c.1. Acid Yet
ff-3, C,1, Acid Yellow 7 (hereinafter referred to as acid dye), C,1, Basic Yellow 1. C.

■, Basic Yellow 2, C, 1, Basic Yellow 11 (or more basic dyes) C, 1, Modern Toy Yellow-2
6 (mordant, acidic mordant dye), C, 1, Disperse Yellow 1. C,1, Disperse Yellow 3, C,1, Disperse Yellow 4 (disperse dye), C0! , Solvent Yellow 2, C, 1, Solvent Yellow 6, C
, 1, Solvent Yellow 14 (all oil-soluble dyes), etc. As a red dye, C, 1, Direct Red ISC.

■, Direct Red 2, C, 1, Direct Red 4
(Direct dye), C,1, Acid Red 8, [1,
Acid Red 13, C,1, Acid Red 14 (all acidic dyes), C,1, Basic Red 2, C,1,
Basic Red 14, C, 1, Basic Red 27
(all basic dyes), C, 1, Modern Tread 21 (mordant, acidic mordant dye), C, 1, Disperse L/, Do 1
．． C, 1, Disper 7, "tdo 4, C, I.

Disperse Red 5 (disperse dye), C, I.

Solvent Red L, C, 1, Solvent Red 3, C
-1, Solvent Red 8 (all oil-soluble dyes) and other blue dyes, C, 1, Direct Blue i, c.

■, Direct Blue a, c, i, Direct Blue 2
2 (or more direct dyes), C, 1, Acid Blue 11 (,
1, Acid Blue, C, l Acid Blue 22 (more acidic dyes), C,1, Basic Proof, C,1,
Basic Blue 9, C, 1, Basic Blue 19 (
basic dye), C,1, Modern Blue 48 (mordant, acidic mordant dye), C,1, Disperse Blue 1c,
1. Disperse Blue 3, C0■, Disperse Blue 5 (more than disperse dye), C0■, Solvent Blue 2,
C, 1, Solvent Blue 11. C.1, Solvent Blue 12 (oil-soluble dyes), etc.

A low melting point substance such as paraffin wax, water glass, etc. may be added to the colorant solution or dispersion in order to prevent the release of inclusions or to provide some binding force to the photoreceptor. The content of the colorant in the colorant solution or dispersion is 0.005~
The IO weight % is preferably 0.01 to 5 weight %.

In addition to the above-mentioned gum arabic and gelatin, the film-forming polymeric substances constituting the first wall membrane (inner wall membrane) include collagen, casein, fibrinogen, hemoglobin, polyamino acids, agar, sodium alginate, and carrageenan. , konjac mannan, dextran sulfate,
Ethyl cellulose, nitrocellulose, carboxymethyl cellulose, acetyl cellulose, nylon, tetron, polyurethane, polycarbonate, formalin naphthalene sulfonic acid condensate, amino resin, marquid resin, silicone resin, maleic anhydride copolymer (ethylene, vinyl methyl ether, etc.) , acrylic acid, methacrylic acid-based copolymers, polyvinyl chloride, polyvinylidene chloride, polyethylene, polystyrene, polyvinyl acecool, polyacrylamide, polyvinylbenzenesulfonic acid, polyvinyl alcohol, synthetic rubber, and the like.

Furthermore, the synthetic resins forming the second wall membrane (outer wall membrane) include polycarbonate, polyester, polyamide, polyether, polyolefin, polystyrene, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-ethylene/based Unsaturated monoolefin copolymer, styrene-vinyl ester copolymer, styrene vinyl ester copolymer, styrene-acrylonitrile copolymer, styrene-methacrylonitrile copolymer, styrene-acrylamide copolymer, styrene-vinylidene halide Copolymer, polyvinyl acetate, or two of these
Examples include primary or ternary or higher copolymers and mixtures of these polymers, which are used in the form of aqueous dispersions.

Magnetic substances mixed into this synthetic resin include metals such as cobalt, iron, and nickel, aluminum, cobalt, copper, iron, lead, magnesium, nickel-tin, zinc, gold, silver,
Alloys or mixtures of metals such as antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and zirconium, aluminum oxide, iron oxide, copper oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide and metal compounds, including metal oxides, such as magnesium oxide,
Mention may be made of refractory nitrides such as chromium nitride, carbides such as tungsten carbide and silica carbide, ferromagnetic ferrites, and mixtures thereof.

Further, it is preferable to use a colored magnetic material as the magnetic material in order to improve the sharpness of color.

Suitable colored magnetic materials include iron oxide (Begala) for red color, Ni surface coated with oxidized steel, and N.
Adsorbed cadmium red, cobalt and its compounds for yellow color, iron oxide, N for yellow color.
There are some that have cadmium yellow adsorbed on 1.

In both cases, fine particles are generated by a precipitation method to produce a glossy surface, or a chemical surface treatment is applied after crushing. The content of this magnetic material is suitably 20 to 70% by weight, preferably 40 to 60% by weight, based on the total amount of the developer.

Next, the latter powder developer is one in which a colorant and a magnetic material, or a colored magnetic material is dispersed in a transparent resin.

The method for producing the powder developer will be described below.

As the magnetic material contained in the developer, a material that effectively selectively reflects the color of the colored developer when the developer is stacked is used, and as the resin of the developer, the color of the magnetic material is compensated and enhanced. By using a material with a striking color or a mixture of such dyed or colored objects, direct overlapping and trochanteric overlapping can be performed.

The magnetic material preferably has a particle size of 0.5 to 10μ, a smooth, woven or spherical surface, and a glossy surface. A colorless or colored magnetic material is placed in a colored transparent resin or a transparent resin mixed with a coloring agent, or the surface of the magnetic material is coated with a transparent or translucent colorant, and the color of the colorless transparent resin or magnetic material is insufficient. In some cases, it is made by placing it in a colored transparent resin or a transparent resin mixed with a coloring agent. The ratio of magnetic material and resin is 1 to 1 resin to 1 magnetic material, compared to the capacity when used as a superposition developer.
50, and the particle size as a developer is suitably 5 to 20 microns.

The magnetic material and coloring agent used in the above developer are the same as those in the microcapsule developer, and the colored magnetic material is also the same.

Further, resins used in the powder developer include phenol, polyester, polystyrene, alkyd, acrylic, polyethylene, etc. Furthermore, the synthetic resins used in the microcapsule developer can also be used.

An example of a copying process including a method of developing together developers charged with mutually different polarities will be described below.

Two methods are known for forming electrostatic latent images. One method is to perform primary charging to a predetermined polarity on a photoreceptor, which is made by laminating two photoconductive layers with different spectral sensitivity characteristics on a conductive substrate, and then A secondary charge with a polarity opposite to that of the electrification is applied to form an electric double layer on each photoconductive layer of the photoreceptor so that the dipole moments thereof are in opposite directions, and then an optical image of the original is irradiated, There is a method in which the surface potential of the photoreceptor at a portion corresponding to the background portion of the original is set to approximately O, and the electrostatic latent image portions corresponding to each color image are formed by distribution of potentials on the surface of the photoreceptor with opposite polarities.

Another method is to use an electrostatic recording needle on the photoreceptor and form an electrostatic latent image using recording signals of ■ and ○.

The electrostatic latent image created by one of the above methods is developed by the developing method of the present invention, and the obtained toner image is corona charged with a corona charger to align the polarity, and then recorded. Transfer and fix onto paper. The photoreceptor is cleaned by a cleaning device, and any remaining electrostatic latent image is removed by a corona charger for charge removal, and the photoreceptor is used repeatedly.

The present invention will be explained below.

(Example 1) As a sexually charged black developer, the following was mixed, heated, dissolved and cooled, then crushed and classified to have an average particle size of 15μ, and as a fluidizing agent,
A material containing 0.2% silica was used.

On the other hand, as a negatively charged red developer, it is mixed, heated, dissolved, and cooled, then pulverized and classified to have an average particle size of 15μ, and used as a fluidizing agent.
A material containing 0.2% silica was used.

These developers were mixed in an equal ratio to form a composite developer.

It is desirable that the mixing ratio be close to equivalence, but it is particularly desirable that either of them should not exceed 2:8 even if it is large.

The following description will be made using the apparatus shown in FIG.

FIG. 4 is a schematic diagram showing the configuration of the first embodiment, in which l is an electrostatic recording needle, and an electrostatic latent image 4 is created on the photoreceptor 3 by recording signals 2 of ■ and ○. 5 is a magnetic brush developer for developing the electrostatic latent image 4; 6 is a corona charger for aligning the charge polarity of the developer; 7 is recording paper made of plain paper; 8 is for transferring onto the recording paper 7. Corona charger for transfer, 9
is a heater for fixing, lO is a fur brush for cleaning, and ll is a corona charger for static elimination.

In the experiment, polyethylene terephthalate (PET) with a thickness of 25μ and aluminum vapor-deposited on the back side was used as the photoreceptor, and
Electrostatic latent image 4 of 0V and -400V is developed with a developer so that ■ is red and ■ is red.
was developed with the above composite developer in black.

The magnetic brush developing device 5 includes a sleeve 5-a, which is a rotating developer conveying member, and a fixed magnet 5-b, which faces the internal electrostatic latent image 4. In the development, the gap between the photoreceptor sleeves 5-a is maintained at 0.3 mm, and a 0.2 mm thick developer layer is fed into the development area in this state.
, by applying an alternating current of 500 Hz. In the absence of this alternating current application, a mixture of black developer and red developer was observed in the image area, and the sharpness of the image was also low.

Next, the composite developer is charged with a corona charger 6 to align the polarity of ○, and then transferred to a recording paper 7 with a transfer corona charger 8, and is heated and fixed with a fixing heater 9 to record. I did it. In addition, for static elimination, corona charger I for static elimination is used.
This was done by setting L to zero potential and adding ■ and ○ coronas.

When adhesive transfer is used as the transfer means, the corona chargers 6 and 8 are unnecessary. That is, in Example 1,
Positive and negative electrostatic latent images are formed on the surface of the photoreceptor, developed using an alternating electric field with a composite developer under magnetic bias, the polarity of the developer is aligned to one polarity by corona charging, and then transferred to recording paper. By doing so, the plain paper was colored without two-color fog at high speed. There is an advantage that a high-quality recorded image with high sharpness can be obtained without any turbidity due to polyvinylcarbazole and trinitroflu.

(Example 2) An embodiment will be described using the apparatus shown in FIG.

FIG. 5 is a schematic diagram of the configuration without showing the second embodiment, and 13 is an optical system combining a red light 13-a and a corona charger 13-b;
14 is a corona charger, and 15 is an exposure system.

With these, an electrostatic latent image 4 is formed on the photoreceptor 3.

5 is a magnetic brush developing device for developing the electrostatic latent image 4; 6 is a corona charger for aligning the charge polarity of the toner; 7 is a recording paper made of plain paper; 8 is for transferring onto the recording paper 7. 9 is a heater for fixing; IO is a fur brush for cleaning; 16 is a corona charger for static elimination; 16 is a corona charger for transfer;
-b and white light 16-a are combined.

In the experiment, an aluminum plate was used as a conductive substrate, and selenium with a purity of 99.99% was deposited on the aluminum plate to a thickness of 12 μm. On this selenium layer, polyvinylcarbazole-trianitrofluorenone was coated to a thickness of 18 μm.The mixing ratio of olenon to the unit monomer of polyvinylcarbazole was 0.1 mole of trinitrofluorenone. Both the selenium layer and the polyvinyl rubbersolutolinitropholenon layer (hereinafter abbreviated as OF2 layer) are bipolarly chargeable, and the OPC layer is translucent.

While uniformly exposing this photoreceptor 3 to red light 13-a obtained by a red filter VR64 made by Susho,
KV (7) cous charger 13-b4: +700Vi
:: The sample was firstly charged, and then charged to -400V in the dark using a -5.2KV corona charger 14.

Next, exposure was performed using the exposure system 15 with a light image of the document having a red image and a black image on a white background, and the surface potential of the photoreceptor at the part corresponding to the white background of the document was -50v1.The electrostatic charge corresponding to the red image and the black image was An electrostatic latent image was formed in the latent image portion by the photoreceptor surface potential distribution of +300V and -400V, respectively.

This was developed using the composite developer used in Example 1 in a magnetic brush developer 5. The magnetic brush developing device 5 is composed of a rotating sleeve 5-a and a fixed magnet 5-b inside which faces the electrostatic latent image 4. During development, the gap between the photoreceptor sleeves is maintained at 0-3ma+i, and a developer layer of 0.4m+a is fed into the development area in this state at 0.4K.
This was done by applying an alternating current of V, 1500 Hz.

When this alternating current was not applied, a mixture of black developer and red developer was observed in the image area, and the sharpness of the image was also low.

Next, the composite developer is charged with a corona charger 6 to align the polarity of ○, and then transferred to a recording paper 7 with a transfer corona charger 8, and is heated and fixed with a fixing heater 9 to record. I did it. In addition, for static elimination, corona charger 1 for static elimination
This was carried out by setting 1 to zero potential and adding an alternating current corona and white light.

Further, when adhesive transfer is used as the transfer means, the corona charger 6.8 becomes unnecessary. That is, in Example 2, positive and negative electrostatic latent images were created on the surface of a photoreceptor, developed using an alternating electric field with a composite developer under magnetic bias, and the polarity of the developer was changed to one polarity by corona charging. The method of aligning the images, transferring them to transfer paper, and fixing them has the advantage of being able to perform two-color, high-quality recording on plain paper at high speed.

Furthermore, if one of the colored particles of the developer to be mixed is a developer that does not contain a magnetic material, for example, a pale yellow or blue developer, the color reproducibility will be poor because it does not contain a magnetic material. It can record well and in clear colors.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the potential of the electrostatic latent image and the amount of developer contributing to development; Figure 2 shows the relationship when the positive charging developer in Figure 1 contains a magnetic substance. Figure; Figure 3 is a diagram showing the relationship when magnetic material is contained in a composite developer; Figure 4 is a diagram showing Example 1 of the present invention; and Figure 5 is a diagram showing Example 2 of the present invention. It is a diagram. 1 is a recording electrode, 2 is a recording signal, 3 is a dielectric drum, 4 is an electrostatic latent image, 5 is a developing device, 6 is a corona charger, 7 is a recording paper, 8 is a transfer corona charger, 9 is a fixing device 10 is a fur brush for cleaning, 11 is a corona charger for static elimination, 12
is an AC power supply, 13-a is a red light, 13-b is a corona charger, 14 is a corona charger, 15 is an exposure system, 16-a
16-b is a white light, and 16-b is a corona charger for static elimination.

Claims (1)

[Claims] A developer having colored particles containing a magnetic substance and colored particles having a charge polarity different from the colored particles and not containing a magnetic substance is placed on a developer conveying member containing a built-in magnet body, and an alternating electric field is applied to the developer. A developing method in which an electrostatic latent image on an image support is developed in a developing area to which is applied.