JPH0210387A - Image forming device - Google Patents

Abstract

PURPOSE:To form a high quality image without the phenomena of impressions of paper, contact winding or central blanking by developing an electrostatic charge image on a holding body with a specific one component developer, and then electrostaticly transferring this toner image under a specific electric field condition. CONSTITUTION:The holding body surface 1 is charged to the negative polarity by a primary electrifying device 2, a latent image is formed by an exposure 5, and then it is reversal developed with the one component developer 13, which contains 0.01-1.0pts. wt., of a coating material forming a smooth surface with the contact angle of water at 80% or more, using a developing device 9. At a transferring part, a transferring paper P is charged to the positive polarity from the backside by a transferring electrifying device 3, and the current loaded toner image on the surface 1 is transferred. At this time, the ratio of transfer electrifying electric field Vtr/primary electrifying electric field Vpr is negative, and the absolute value is specified to 0.5-1.6. The charge is eliminated by a destaticizing brush 10, the paper P is curvature-separated and heat- fixed by a roller 7. After the residual developer of a drum 1 is eliminated by a cleaning device 8, destaticizing is carried out by an erasing exposure 6, and then the process is repeated.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an image forming method using a monocomponent developer containing a negatively charged toner and a film-forming component. The present invention relates to an image forming method including a step of successfully transferring the above toner image to a transfer material.

[Prior Art] Conventionally, in electrophotographic apparatuses, a normal development method in which a non-exposed area is developed is generally used. This is because the reflected light from the original is optically processed and then projected onto the photoreceptor.
Development is performed on non-exposed areas (character areas of the original) where there is no reflected light.

Recently, electrophotographic systems have come to be used not only for obtaining copied images but also for printers used for computer output. For printer use, one light emitter (
semiconductor laser, etc.) is turned on and off according to one image value number (
ON-OFF), and the light is projected onto the photoreceptor.

At this time, the printing rate (ratio of printing area per page) is usually less than 30%, and the method of exposing the character part (
Reversal development) is advantageous in terms of luminescent life.

In addition, reversal development is used in devices that output positive images and negative images from the same document (for example, microfilm output devices), and in addition, in order to develop two or more colors in the same device, normal development is also used. It has come to be used in devices that combine reversal development and reversal development.

[Problems to be Solved by the Invention] However, reversal development has the following problems. In normal development (hereinafter referred to as normal development), the transfer electric field has the same polarity as the negative charge, and the image carrier ( Even if a transfer electric field is applied to the photoreceptor after passing through the photoreceptor (hereinafter referred to as paper, etc.), its influence is erased by erase exposure (6 in FIG. 1).

On the other hand, the transfer electric field in reversal development has the opposite polarity to the -order charge, and even after passing through the paper, when the transfer electric field is applied, a charge of the opposite polarity occurs on the photoreceptor, which cannot be erased with erase exposure and only one image has shading. It will come to you. This is a "paper trail"
This is a phenomenon called.

As for the paper trail, there is an f-stage that lowers the transfer current after the paper has passed, as seen in Japanese Patent Application Laid-Open No. 60-258173. ) is safe, and the more complicated the equipment, the higher the equipment cost. Another possible method is to lower the transfer electric field so that the photoreceptor is not charged with the opposite polarity. However, this method lowers the transfer efficiency, resulting in a reduction in image quality due to poor transfer.

Another problem with the reversal development method is that the photoreceptor and paper are charged with opposite polarities, so when charged with a strong electric field, the photoreceptor and paper will electrostatically attract each other, causing transfer problems. Even after the process is finished, the paper does not separate and gets into the next process (cleaning process, etc.), causing paper jams, etc. This is a phenomenon called "wrapping." Japanese Patent Publication No. 56-6
As seen in Japanese Patent No. 0470, there is a means to prevent the photoreceptor from coming into close contact with paper or the like. However, this method is not necessarily effective in reversal development. That is, this is considered to be because the close contact during separation in the transfer process of reversal development is stronger than that of normal development. Another method, as seen in U.S. Pat. No. 3,357,400, is an apparatus that includes separate charging or belt separation as an auxiliary means for separation. Although this is effective against the wrapping phenomenon, it is not effective against the paper trail phenomenon. This is because the separation charge is smaller than the transfer charge, and it even affects the potential of the photoreceptor. Depends on what you don't do.

Another method is to reduce the electrostatic attraction force by lowering the transfer electric field, but as mentioned above, this method is likely to cause a reduction in image quality due to poor transfer. Postcards that are disadvantageous for transcription due to a decrease in 01
(Unable to meet the diverse needs of P films, etc.) Also, if the transfer electric field is lowered, some transfer defects may occur in areas where developer tends to concentrate (edge development areas), such as image outlines and line drawing areas. ``transcription omission'' occurs.This is,
This is thought to be due to the fact that more developer is deposited in the edge development area than in the normal area, and developer aggregation is more likely to occur, resulting in a lower response to the transfer electric field.As a result, it is difficult to obtain a high-quality image that is faithful to the Wl image. It has the problem of becoming.

An object of the present invention is to provide an image forming method that solves the above-mentioned problems.

An object of the present invention is to provide a transfer process that can obtain high-quality images that are faithful to the latent image, regardless of the conditions of the transfer carrier, in image forming methods such as reversal development methods, where transfer using a low transfer electric field is a drawback. An object of the present invention is to provide an image forming method having the following features.

An object of the present invention is to provide an image forming method in which phenomena such as "paper marks,""wrapping," and "transfer missing" are free or suppressed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method that does not cause hollowing even in a low transfer electric field such as in a reversal developing device and has good durability.

[Means for Solving the Problems] The present invention has been made to achieve the second object, and is to develop an electrostatic image on an electrostatic image carrier with a one-component developer, In an image forming method in which a developer image formed on a holder is electrostatically transferred to a transfer material, a coating substance that forms a slippery surface with a contact angle with water of 80% or more on the surface of the holder is used. ．． U~! , 0 parts by weight (100 parts by weight of toner) is used, and the primary charging electric field Vp
The ratio of r to the transfer charging electric field Vtr (V tr/V pr
) is negative and (V tr/V p r)
The method is characterized in that a toner image is electrostatically transferred under conditions where the absolute value of is 0.5 to 1.6.

The film-forming substance used in the image forming method of the present invention is silicone oil represented by the following formula: R: Alkyl group having 1 to 3 carbon atoms R': Alkyl, halogen-modified alkyl.

Silicone oil modified group R" such as phenyl and modified phenyl: Alkyl group or alkoxy group having 1 to 3 carbon atoms m: An integer from 5 to 100 n An integer from 20 to 50, such as dimethyl silicone oil, alkyl modified Examples include silicone oil, α-methylstyrene-modified silicone oil, chlorphenyl silicone oil, fluorine-modified silicone oil, and the like.

In addition, fatty acid metal soap (R-G-
0) nM R: aliphatic or unsaturated aliphatic having 10 to 20 carbon atoms n: an integer of 1 to 3 M: a metal with a valence of 1 to 3, such as zinc stearate, zinc laurate,
Examples include zinc myristate, calcium stearate, and aluminum stearate.

Although examples of film-forming substances have been given above, the present invention is not limited to these.

The contact angle of the surface of the electrostatic image carrier with water is measured as follows. Using a Kyowa contact angle meter GA-O9, 104 g of ion-exchanged pure water was dropped onto the surface of the sample, which was attached so that the sample surface was horizontal when viewed from a direct mirror. 1/2 θ is measured from the straight mirror, and the contact angle θ is determined from this. It is thought that film formation is mainly carried out by the cleaning process.

In other words, the coating material that moves with the developer and remains untransferred onto the electrostatic charge image carrier is cracked or stretched by the mechanical action during the cleaning process, resulting in a water-repellent coating on the carrier. Form a film.

The amount of film substance added is 0 to 100 parts by weight of toner.
It is preferable that the amount of O is 1 to 1.0 parts by weight. If it is less than 0.01 parts by weight, no effect will be observed and problems related to transfer will occur. Moreover, if it exceeds 1.0 parts by weight, a film will be formed on parts such as the developer carrier, causing problems regarding development. Particularly preferably 0.03 to 0.5 parts by weight.

The film material used in the present invention is characterized by behaving together with the developer. This is JP-A-56-1
This method is completely different from the method disclosed in Japanese Patent No. 30470, in which particles are actively placed on non-image areas to reduce the adsorption force between the transfer material and the photoreceptor.

According to the method disclosed in Japanese Patent Application Laid-Open No. 5fl-Et0470, the wrapping phenomenon can be improved without lowering the transfer electric field, but it is not effective against the single paper mark phenomenon, and the transfer rate can be improved under a low transfer electric field. It has no effect.

The transfer process used in the present invention includes an electrostatic transfer method using an electric field generated by a corona discharge charger, a contact roller charger, or the like. Transfer conditions are measured as follows. Referring to FIG. 1 of the accompanying drawings, the cleaning device M8. Developing device9. The transfer charger 3 and the like are removed, and the photoreceptor (photosensitive drum) 1, which is an electrostatic image holder, is charged with the negative charger 2. leaked light,
After substantially completely blocking light and charging the photoreceptor 1 for one revolution, the surface potential of the photoreceptor 1 is measured with a surface electrometer. The value of the surface potential at this time is vpr[vl.0 Next, after removing the charge from the photoreceptor surface by wiping the surface of the photoreceptor with a cloth impregnated with alcohol, remove the -order charger 2, and remove the transfer charger. 3
After charging the photoreceptor l for one revolution, the surface potential of the photoreceptor is measured. The value of the surface potential at this time is V
tr[V] In the present invention, V tr/V p
The value of r is 0.5 to 1.6. If the absolute value is less than 0.5, the transfer electric field is too low and image deterioration is likely to occur during transfer; if the absolute value exceeds 1.6, the transfer electric field is too strong and the photoreceptor is It is easy to be charged with electricity, and paper trail phenomenon and wrapping phenomenon tend to occur.

It is 1.4.

The present invention is effective for an image forming method (apparatus) using an organic photoreceptor (hereinafter referred to as an OPC photoreceptor), and the OPC photoreceptor is a multilayer OPC formed of a multilayer structure having at least a charge generation layer and a charge transport layer. This is particularly effective for image forming methods using reversal development methods. In the APE photoreceptor, when the photosensitive layer is charged to the opposite polarity, the charge movement is slow, and this tendency is particularly noticeable in laminated OPCs.
The present invention is particularly effective since paper marks are likely to occur17.

The values of V and r used in the present invention are -300 to -i,
ooorv ] is better, 4S knee 5oo ~ -90
0 [V] is preferable. If it is less than -300 [V], it is difficult to secure a potential difference during development and the image tends to become unclear. On the other hand, if it exceeds -1,000 [V], the photosensitive layer due to the electric field -500 to -900 [V
] is particularly preferred.

The image forming method of the present invention is an image forming method in which a transfer material is separated from a photoreceptor using the elastic force of the transfer material (paper, etc.), the curvature of the photoreceptor, a static elimination brush, etc., without using mechanical separation means. It is particularly effective against (devices). The separation state in devices that do not have a mechanical separation mechanism depends on the transfer conditions.
The present invention is particularly effective because the windings are prone to cracking.

The present invention is particularly effective in an image forming method (apparatus) using a photoreceptor having a diameter ("φ" in FIG. 1) of 50 mm or less. Devices that use photosensitive drums with a diameter of 50 mm or less are intended to be miniaturized, and the number of parts must be reduced. Usually, the separation process consists of separation using only the elastic force of paper and a static elimination brush 7, etc. (See Figure 2).

At this time, the static electricity removal process only removes static electricity from paper, etc.
Usually, it does not affect the surface potential of the photoreceptor.

The image forming process will be explained with reference to FIG. - Charge the surface of the photoreceptor to negative polarity with the charger 2, and perform H! by image scanning with exposure 5 using a light source or laser light. An i-image is formed, and the latent image is reversely developed using a one-component magnetic developer 13 in a developing device 9 equipped with a magnetic blade 11 and a developing sleeve 4 containing a magnet. In the developing section, a bias is applied between the photosensitive drum 1 and the developing sleeve 4 by a bias applying means. When the transfer paper P is conveyed and reaches the transfer section, the transfer charger 3 charges the transfer paper P with positive polarity from the back side (the opposite side to the photosensitive drum side), thereby forming a negatively charged toner image on the surface of the photosensitive drum. is electrostatically transferred onto the transfer paper P. Immediately after the transfer band 11 passes through the device 3, the transfer paper P is separated from the photosensitive drum 1 by curvature separation while eliminating the charge on the back side of the transfer paper by the static eliminating brush 0. Transfer separated from the photosensitive drum L by 0 curvature separation. The toner image on the transfer paper P is fixed by the heating and pressure roller fixing device 7 .

Further, the one-component developer remaining on the photosensitive drum after the transfer process is removed by a cleaning device having a cleaning blade.
will be removed. After cleaning, the photosensitive drum 1 is neutralized by erase exposure 6, and the steps starting from the charging step by the negative charger 2 are repeated again.Next, the negatively charged toner used in the present invention will be described.

In the present invention, examples of the binder resin for the toner include polystyrene and poly-p-chlorostyrene.

Monopolymers of styrene and its substituted products such as polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid methyl copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer Polymer, styrene-butyl methacrylate copolymer, styrene-α-methyl chloromethacrylate copolymer, styrene-acrylonitrile copolymer,
Styrene-vinyl methyl ether copolymer, styrene-
Styrenic copolymers such as vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride, Polyvinyl acetate, polyethylene, polypropylene, silicone resin, polyester, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenolic resin, xylene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorine Chemical paraffin, paraffin wax, etc. may be used alone or in combination.

In the present invention, among these resins, styrene-
Acrylic copolymers are preferably used, particularly styrene-n-butyl acrylate (St-nBA) copolymer and styrene-n-butyl methacrylate (St-nBMA).
Copolymer, styrene-n-butyl acrylate-2-ethylhexyl methacrylate (St-nBA-2EHMA
) copolymers etc. are preferably used.

Further, as coloring materials that can be added to the toner according to the present invention, conventionally known carbon black, copper phthalocyanine,
Iron black etc. can be used.

As the magnetic fine particles contained in the magnetic toner of the present invention, a substance that is magnetized by being placed in a magnetic field is used, such as powder of a ferromagnetic metal such as iron, cobalt, or nickel, or magnetite, γ-Fe2O3° ferrite. Alloys and compounds such as can be used.

These magnetic fine particles preferably have a BET specific surface area of 2 to 20 m27g, particularly 2.5 to 12g, determined by the nitrogen adsorption method.
7g, preferably magnetic powder with a Mohs hardness of 5 to 7.
The content of this magnetic powder is preferably 10 to 70% by weight based on the amount of toner.

Further, the toner of the present invention may contain a charge control agent if necessary, such as a metal complex salt of a monoazo dye; salicylic acid;
A negative charge control agent such as a metal complex salt of alkyl salicylic acid, dialkyl salicylic acid or naphthoic acid is used.

Furthermore, the magnetic toner according to the present invention has a volume resistivity of 10
It is preferable that it is 10Ω・cm or more, especially 1012Ω・C■ or more in terms of tripod charge and electrostatic transferability. c7) Defined as a value calculated from the current value after 1 minute has passed after applying an electric field.

The negatively charged magnetic toner used in the present invention must have a tripocharge amount of -8 gc/g to -20 pc/g. If it is less than -8gc/g, the image density tends to be low, and the effect is particularly noticeable under high humidity, and -20p
If it exceeds c/g, the toner charge will be too high, resulting in thin line images and poor images especially under low humidity.

The negatively charged toner particles of the present invention are 25°C, 50 to 60°C.
% RH overnight - 10 g of toner particles and a non-resin-coated carrier iron powder (for example, Nippon Tetsuko Co., Ltd. E
FV200/300) 90 g under the above environment in an aluminum pot with a volume of approximately 200 c, c, (hold by hand and shake up and down approximately 50 times)
The toner particles are mixed and the tripocharge amount of the toner particles is measured by a conventional blow-off method using an aluminum cell with a 400 mesh screen.

By this method, toner particles whose measured tripocharge is negative are defined as negatively chargeable toner particles.

In addition, the volume average particle diameter of the toner particles is 5 to 30μ■, preferably 7 to 15μ.The content of 4 endomeres or less in the zero number distribution is 2% to 20%, preferably 2 to 18%.
is good.

A Coulter Counter T^-■ model (manufactured by Coulter Co., Ltd.) was used as the toner particle size measuring device, and an interface (manufactured by Nikkaki Machinery Co., Ltd.) that outputs the number average distribution and volume average distribution, and 0X-1 personal combination, - (manufactured by Canon), and the electrolyte is 1st class sodium chloride.
%NaC! ! Prepare an aqueous solution. Measurement method and 1. Then, 0.1"5 mi! of a surfactant, preferably an alkylbenzenesulfonate salt, is added as a dispersant to 100 to 150 sffi of the electrolytic aqueous solution, and 0.5 to 5 sffi of the measurement sample is added.
Add 0mg. The electrolyte in which the sample was suspended was dispersed for about 1 to 3 minutes using an ultrasonic dispersion machine, and then dispersed using the Coulter Counter TA-11 model to obtain a particle size of 2 to 40 using a 100p aperture. The distribution is measured to determine the volume average distribution and the number average distribution.

The toner according to the present invention is generally manufactured as follows.

(2) Uniformly disperse the binder resin and optionally the magnetic material 9 as a coloring agent such as teno dye pigment using a mixer such as a Henschel mixer.

(2) Melt and knead the dispersion obtained above using a Nigu, extruder, roll mill, or the like.

■After coarsely pulverizing the kneaded material with a cutter mill, hammer mill, etc., finely pulverizing it with a jet mill, etc.

-@) Using a zigzag classifier or the like, the finely pulverized product is classified to have a uniform particle size distribution, and then the toner is produced.Other toner manufacturing methods include polymerization methods, capsule methods, and the like. An outline of these manufacturing methods will be described below.

(Polymerized toner) (1) A polymerizable monomer and, if necessary, a polymerization initiator 9, a colorant, etc. are granulated in an aqueous dispersion medium.

(2) Classifying the granulated monomer composition particles into appropriate particle sizes.

(2) Polymerizing the monomer composition particles having a specified particle size obtained by the above classification.

(2) After removing the dispersant through appropriate treatment, the polymerization product obtained above is washed with water and dried to obtain a toner.

(Capsule toner) ■Knead resin and, if necessary, magnetic powder etc. using a kneader or the like to obtain a toner core material in a molten state.

■Pour toner core material into water and stir vigorously to create fine particle core material.

(2) Put -L core material fine particles into a shell material solution, drop a poor solvent while stirring, and encapsulate the core material surface by covering it with the shell material.

■ Take the capsules obtained above and dry them to obtain toner.

The developer used in the image forming method of the present invention preferably further contains hydrophobic silica fine powder.

In the case of a negatively chargeable magnetic component developer, it contains negatively chargeable hydrophobic silica fine powder and positively chargeable resin fine particles treated with a silane coupling agent and/or silicone oil, and contains 100 weight of negatively chargeable magnetic toner. The content is preferably 0.01 to 3 parts by weight per part of the silica.

The fine silica powder used in the present invention is so-called dry silica or fumed silica, which is produced by vapor phase oxidation of a silicon halide compound, and whose surface has been treated with a silane coupling agent and/or silicone oil. It is a fine silica powder.

A preferred silane coupling agent includes hexamethyldisilazane (HMDS). Further, as a preferable silicone oil, one having a viscosity of approximately 50 to 1,000 centistokes at 25°C is used,
For example, dimeryl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, chlorphenyl silicone oil, fluorine-modified silicone oil, etc. are preferred. For the purpose of the present invention, -OH group, -
COOH group.

Silicone oil containing a large amount of -Nl2 groups, etc. is not preferred.

Known techniques are used for the silicone oil treatment; for example, fine silica powder and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or silicone oil may be injected onto the base silica. It's also good. Alternatively, it may be prepared by dissolving or dispersing silicone oil in a suitable solvent, mixing it with the base silica fine powder, and removing the solvent.

The degree of hydrophobicity of fine silica powder in the present invention uses a value measured by the following method. Of course, other measurement methods can also be applied while referring to the measurement method of the present invention.

Put 100mf of pure water and 1g of sample into a sealed container,
Mix on a shaker for 10 minutes. After shaking, for example, let stand for several minutes to separate the silica powder layer and the water layer, collect the water layer, and measure the transmittance at a wavelength of 500 nm using blank pure water that does not contain fine silica powder as a reference. The transmittance value is determined as the degree of hydrophobicity of the treated silica.

The degree of hydrophobicity of the silica fine powder in the present invention is 80% or more (more preferably 83% or more).

If the degree of hydrophobicity is less than this, a high-quality image cannot be obtained due to moisture adsorption of the silica fine powder under high humidity.

Further, the silica fine powder is negatively chargeable.

The tripo value of negatively charged silica fine particles is measured by the following method. That is, 2 g of fine silica powder left overnight in an environment of 25° C. and 50 to 60% RH and a non-resin-coated carrier iron powder having a main particle size of 200 to 300 mesh (for example, Nippon Iron Powder Co., Ltd.) Manufactured by EFV2GG/30G
) were thoroughly mixed in an aluminum pot with a capacity of 200 c, c, under the above-mentioned environment (by holding it in the hand and shaking it up and down approximately 50 times), and placed in an aluminum cell having a 400 mesh screen. The trypo charge amount of the silica fine particles is measured by the usual blow-off method. By this method, silica particles whose measured trypo charge is negative are defined as negatively charged silica particles.In the present invention, the trypo charge amount is 1100 c/
Silica microparticles having a particle size of ~-300 μc/g are used.

The above silica fine particles are 0% per 100 parts by weight of toner particles.
．． The effect is exhibited when the amount is 0.01 to 3 parts by weight, and particularly preferably, a developer having excellent stability is provided when added in an amount of 0.05 to 2 parts by weight.

If it is less than 0.01 parts by weight, it causes a decrease in image density, and if it exceeds 3 parts by weight, fogging cannot be suppressed, which is not preferable.

Regarding the preferred form of addition, it is preferable that 0.01 to 1.5 parts by weight of the treated silica fine powder be attached to the surface of the toner particles based on the weight of the developer.

[Example] Hereinafter, parts mean parts by weight.

Example 1 The above mixture was melt-kneaded in a two-screw Rougoo heated to 180°C, cooled, and the cooled mixture was milled in a hammer mill (IJH
A mesh with an opening diameter of two layers was coarsely ground to a pass level using an IjE type powder (JiN&), and then finely ground to about 10 JL using a jet mill (wind-powered grinder). The finely pulverized product was classified using an OS classifier (wind-type classifier) so that the volume average particle diameter measured with a Coulter counter was 11.5μ■, and a negatively charged insulating magnetic toner was prepared. .

This insulating magnetic toner had a tripocharge amount of 113 c/g with respect to the iron powder carrier as measured by the blow-off method.

Next, to 100 parts of this negatively charged magnetic toner, 0.1 part of zinc stearate (manufactured by Sakai Chemical Co., Ltd. 5Z-2000) and fine hydrophobic silica powder (BET specific surface area 130II2) were added.
/g of dry silica treated with hexamethyldisilazane and then treated with dimethyl silicone; degree of hydrophobicity 9
5%, tripo charge amount -1901 Lc/g) was added and mixed in a Henschel mixer to prepare a -component developer.

The obtained developer was subjected to reversal development using a commercially available copying machine FC-5 (manufactured by Canon Co., Ltd., APC laminated type negatively charged photoreceptor, curvature separation type using a drum diameter of φ30, static elimination needle applied with a bias of -1,000 kV). Under the transfer conditions shown in Figure 1 (Vtr = +700 V), a gap was set so that the developer layers on the photosensitive drum and the developing drum (with magnet included) were not in contact with each other, and an alternating current bias (f = 1.800 Hz) was modified for use. .

Vpp" 1, EiOOV) and DC bias (Voe=-500V) were applied to the developing drum to produce an image. The toner fixed image after 0-image printing and fixed by heating and pressure roller is shown below. Table 1 shows the results that we would like to evaluate.

(1) Photoconductor surface condition: Normal copying machine plain paper (75g
/厘2) After passing 1000 sheets, measure the contact angle with water on the surface of the photoreceptor.

The numerical value is the contact angle (θ) value (2) Image density 2 Ordinary copying machine plain paper (75 g/m2
) Evaluation was made by maintaining image density when 1000 sheets were passed.

O (good): 1.35 or more, Δ (fair): 1.0 to 1.34
゜× (not possible): Less than 1.0 (3) Transfer condition: Strict transfer conditions, 120 g/m
A thick paper No. 2 was passed through the paper, and transfer removal was evaluated based on the condition.

0: Good, Δ: Practical 2× = Not Practical (1,000 sheets of 8 sheets of 850 g/intestine 2 with 0@ were passed through, and the occurrence of paper jams was evaluated.

0: I Ii1 or less/x, ooo pieces.

Δ: 2 to 4 times/1,000 sheets.

×: 5 rotations -), /1,009 sheets (5) Paper trace: An evening image was output on all pages and evaluated based on its uniformity.

O: Density difference within 0.05, Δ: 0.08 to 0.15° ×: 0.16 or more (6) Image quality: Toner scattering, roughness, etc. were visually evaluated.

O: Good, Δ: Practical, ×: Not Practical Example 2 Images were printed in the same manner as in Example 1, except that the transfer conditions were changed so that the ratio of V tr / V pr was -0.7. I did it. The results are shown in Table 1.

Example 3 Image printing was carried out in the same manner as in Example 1, except that the transfer conditions were changed so that the ratio of V tr / V pr was −1.5. The results are shown in Table 1.

Example 4 Image formation was carried out in the same manner as in Example 1, except that aluminum stearate was used as the coating material. The results are shown in Table 1.

Example 5 A developer was prepared in the same manner as in Example 1, except that magnesium laurate was used as the film material,
Images were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6 A developer was prepared in the same manner as in Example 1, except that calcium myristate was used as the film material,
Images were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7 A developer was prepared in the same manner as in Example 1 except that dimethyl silicone oil was used as the film material,
Images were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 8 A developer was prepared in the same manner as in Example 1, except that methylphenyl silicone oil was used as the film material, and images were formed and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 9 A developer was prepared in the same manner as in Example 1, except that 0.02 part of zinc stearate was used,
Images were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 10 A developer was prepared in the same manner as in Example 1, except that the amount of zinc stearate added was 0.8 parts, and images were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 A developer was prepared in the same manner as in Example 1, except that no film material was used, and images were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 A developer was prepared in the same manner as in Example 1, except that the transfer conditions were changed so that the ratio of V tr / V pr was -2.0, and an image was produced in the same manner as in Example 1. The test was carried out and evaluated. The results are shown in Table 1.

Comparative Example 3 A developer was prepared in the same manner as in Example 1, except that the transfer conditions were changed so that the ratio of Vtr/Vpr was -0.3, and image formation was performed in the same manner as in Example 1. was conducted and evaluated. The results are shown in Table 1.

Comparative Example 4 A developer was prepared in the same manner as in Example 1, except that 1.5 parts of zinc stearate was added, and images were produced and evaluated in the same manner as in Example 1. Results first
Shown in the table.

(Margin below)

[Brief explanation of the drawing]

In the accompanying drawings, FIG. 1 is a diagram schematically showing an image forming apparatus used in an embodiment of the present invention, and FIG. 2 is a diagram schematically showing an image forming apparatus used in an embodiment of the present invention, and FIG. The diagram shows an enlarged view of the part. l...Photosensitive drum 2...-Charger 3...
Transfer charger 4...Developing sleeve 5...Exposure
6...Erase exposure 7...Heating pressure roller fixing device 8...Blade cleaning device

Claims (1)

[Claims] In an image forming method in which an electrostatic image on an electrostatic image carrier is developed with a one-component developer and the developer image formed on the electrostatic image carrier is electrostatically transferred to a transfer material, contact with water 8 corners
A one-component developer containing 0.01 to 1.0 parts by weight (100 parts by weight of toner) of a coating material that forms a smooth surface of 0% or more on the surface of the holder is used, and the primary charging electric field V_
The ratio between p_r and transfer charging electric field V_t_r (V_t_r/
Under conditions where V_p_r) is negative and (V_t_r/V_
Under the condition that the absolute value of p_r) is 0.5 to 1.6,
An image forming method characterized by electrostatically transferring a toner image.