JPH0486864A - Developing device for non-magnetic one component type developer - Google Patents

Abstract

PURPOSE:To easily adjust a bristle cutting gap, to make the density of a developer layer on a sleeve uniform and to obtain an excellent image by setting the surface tension of a carrying member within a specified range and forming an electret dielectric layer on a regulating member. CONSTITUTION:The electret layer 40 is provided on a blade 20. Then, the developer 18 is held on the surface of the blade 20 by the electric attraction force of a sleeve 16. When the developer passes between the blade 20 and the sleeve 16, not only the quantity of the developer is physically restricted by the blade 16 but also the developer receives electric repulsive force by the electret having the save polarity as the electrostatically charged polarity of the developer. Therefore, the developer layer is compressed and flocculated by the electric repulsive force of the blade 16. In virtue of the compression and flocculation, allowance is given to the accuracy of the bristle cutting gap, the density of the developer 18 is made uniform and electrostatic charging performance is uniformized. By setting the surface tension of the surface of the developing sleeve 16 at <=31dyne/cm, the developer which is not electrostatically charged yet or which is reversely electrostatically charged does not adhere, and only the developer layer which is completely electrostatically charged fully receives the action of the electret and uniformly receives an electric action, so that the density of the developer layer is made uniform and the excellent image is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrophotographic developing device, and more specifically, the present invention relates to an electrophotographic developing device, and more specifically, it forms a uniform thin layer of a non-magnetic one-component developer on a conveying member, and The present invention relates to a developing device for a non-magnetic one-component developer that forms excellent images with high density and little fog by supplying the developer to the developing area.

(Prior Art) In a developing device in a commercial electrophotographic copying machine,
-Component developers and two-component developers are widely used. - Component developers are broadly classified into non-magnetic developers and magnetic developers, and two-component developers are composed of toner and magnetic carrier. These developers are first triboelectrically charged by stirring or the like in a developing mechanism, and then supplied in a charged state to a developing sleeve, which is a developer conveying member. The developer on the sleeve is conveyed to the photoreceptor and rubbed against the electrostatic image surface on the photoreceptor.

At this time, the developer is attracted to the electrostatic portion by electric Coulomb force and forms an electrostatic image. Then, the developer of this electrostatic image is transferred to a transfer paper or the like and fixed.

In the case of non-magnetic two-component developer, the developer is charged and
Forming a developer layer on a developer conveying member (sleeve) to which a bias voltage is applied, moving it to the surface of a photoreceptor having an electrostatic image, and rubbing the surface with the developer layer under a bias electric field. It has been considered that image formation can be performed using the following methods.

In addition, a developer amount regulating member (doctor blade) is provided close to the sleeve surface, and the doctor blade scrapes the flowing developer layer to regulate the amount of developer supplied to the photoreceptor surface. . The purpose of the doctor blade is to form a thin and uniform layer of developer to prevent fogging or density unevenness caused by supplying too much developer.

(Problems to be Solved by the Invention) In a conventional one-component developing device, an aluminum blade is used as a doctor blade, and the cutting gap (distance between the sleeve and the blade in ml) is about 100 μm. However, conventional doctor blades have the following problems.

The first problem is that the developer is sent to the blade after being stirred, but the developer is sent to the blade with uneven density or concentration depending on the stirring condition, and the blade ends up merely physically processing it. A uniform developer layer may not be formed thereon. In such a case, the image quality becomes non-uniform during development.

The second issue is that conventional doctor blades only physically restrict the developer, and there is no margin for precision (tolerance) in the cutting gap. We have no choice but to be strict. For this reason,
If the blade is not properly adjusted, uneven image density, fogging, etc. are likely to occur.

Furthermore, in the case of a non-magnetic developer, if the surface tension of the developing sleeve is high, there is a risk that the developer will adhere to the sleeve surface while remaining uncharged. Such uncharged developer causes scattering and fogging when supplied to the surface of the photoreceptor, and also impairs development on the electrostatic image area.

In addition, in conventional developing devices, since the developer is not electrically processed by the blade, it is not possible to eliminate the large proportion of uncharged developer that is carried to the photoreceptor. The image becomes uneven.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device for a non-magnetic one-component developer that allows a margin in the cutting gap accuracy and allows easy adjustment of the cutting gap.

It is also an object of the present invention to provide a non-magnetic one-component system that can uniform the density of the developer layer on the sleeve, eliminate uncharged developer supplied to the photoreceptor, and form excellent images during development. An object of the present invention is to provide a developing device for a developer.

A further object of the present invention is to provide a developing device for a non-magnetic one-component developer in which toner scattering and fogging are prevented.

(Means for Solving the Problems) According to the present invention, a support for supporting an electrostatic image, a charging mechanism for charging a non-magnetic one-component developer, and a bias voltage applied to the charged a developer transporting member that holds and transports the developer on the surface by electrical attraction and applies the developer to the electrostatic image area of the support; A non-magnetic one-component system comprising: a developer amount regulating member; the surface tension of the conveying member is within a range of 31 dyn/cm or less; and an electret dielectric layer is formed on the regulating member. A developer development device is provided.

The present invention may be characterized in that the electret layer is made of a fluororesin.

(for production) In the present invention, a developer conveying member (hereinafter referred to as a sleeve) is used.

) by applying a bias potential etc.

A developer layer is electrically formed on the sleeve, and a developer amount regulating member (hereinafter referred to as a doctor blade) provided close to the sleeve thins the developer layer and makes the density uniform. , and after making the amount of charge uniform, it is sent to an electrostatic latent image support (hereinafter referred to as a photoreceptor).

The electret layer of the blade is provided above the sleeve so that the charged polarity of the developer particles is the same or opposite to that of the developer particles.
Preferably they are of the same polarity. In addition, when the polarity is the same as that of the developer particles, and when the polarity is opposite to the developer particles, the effect is substantially the same, although the action is different.

First, when the electret layer has the same polarity as the developer, the following effect is achieved.

The agitated developer is electrically charged and held on its surface by the electrical attraction of the sleeve, and passes through the gap between the blade and the sleeve, ie the tipping gap. In addition to being physically limited in amount by the blade as the developer passes through it,
It receives electrical repulsion from the electret, which has the same polarity as the charging electrode of the developer. Therefore, the developing layer is compressed and agglomerated by the electrical repulsive force of the blade. This compressed aggregation gives a margin to the precision of the cutting gap, makes the density of the developer uniform, and makes the charging property of the developer uniform.

At this time, in the present invention, the surface tension of the surface of the developing sleeve is 31 dyne/am or less, particularly 25 dyn/am.
It is important that it is below e/cm. When the developing sleeve is set in such a range, uncharged or oppositely charged developer due to van der Waals forces etc. does not adhere to it, so only the sufficiently charged developer layer can sufficiently and uniformly carry out the action of the electret. may be subject to negative effects. For this reason,
The above effects are further achieved.

In FIG. 1 for explaining this principle, the sleeve is 16, the photoreceptor is 22, the agitated developer is 18, the doctor blade is 20, and the electret layer is 40. The non-magnetic component developer particles 18 are, for example, negatively charged;
It is carried to the photoreceptor 22 while being attracted to the bias potential of the sleeve 16 . The outer surface of the electret/W40 is charged with the same polarity as the developer particles 18.

The surface tension of the developing sleeve 16 is 31 dyne/a.
m or less.

The developer 18 is regulated to some extent by the blade 20,
The developer layer passing through the sleeve 16 and the electret 40
It is compressed between This is due to the electrical repulsive force of the electret 40 and the electrical attractive force of the sleeve 16. Therefore, the developer can be compressed and formed into a dense layer and thinner than the width of the cutting gap. This means that the conventional regulation based on physical action is further electrically regulated, meaning that the ear cutting gap can be wider than before, and it is understood that the requirements for gap accuracy will be more relaxed. be done. Further, the developer layer located between the electret 40 and the sleeve 16 is dense and has no gaps, and its density or concentration is uniform, and the value of the density itself is not affected by the density unevenness or concentration of the developer during stirring. It is not affected by unevenness and remains almost constant. The fact that the density becomes uniform is the effect described above, but the fact that the density itself is not affected during stirring means that the accuracy error between the ear cutting gaps is reduced,
It is understood that there is a margin for tolerance.

Also, the surface tension of the developing sleeve is 31 dyne/am
Below, in particular, since it is 25 dyne/am or less, the fully charged developer is mainly adsorbed on the sleeve surface, and almost no uncharged developer is adsorbed, so the doctor blade is sure to receive the action of the electret layer. . For this reason, the developing layer sent to the photoreceptor is compressed and thin, and is evenly influenced by static electricity.

Next, when the developer and the electret layer have different polarities, the amount of developer is physically limited by the blade as it passes through, and the electret layer has an electrical attraction force that is opposite to the charged electrode of the developer. receive. Further, even when passing through the sleeve, the sleeve always receives an electrical attraction force. Therefore, the developer layer on the sleeve passes through in a fully extended state in the direction of the blade, which gives margin for the precision of the cutting gap, makes the density of the developer uniform, and makes the charging property of the developer uniform. . Further, as described above, it is important to set the surface tension of the developing sleeve within the above range.

In FIG. 2 for explaining this principle, the sleeve is 16, the photoreceptor is 22, the stirring developer is 18, the doctor blade is 2o, and the electret layer is 42. The non-magnetic one-component developer particles 18 are, for example, negatively charged, and are electrically attracted onto the sleeve 16 and transported to the photoreceptor 22 . The outer surface of the electret layer 42 has a charge opposite to that of the developer 18 . Further, the surface tension of the developing sleeve 16 is 31 dyne/am or less.

The developer 18 is regulated to some extent by the blade 20,
The spiked developer that is passing through is stretched between the sleeve 20 and the electret 42. This is due to the electrical attraction force of the electret 42 and the electrical attraction force of the sleeve 16. Therefore, the developer layer under tension tends to be acidized at the balance point of these suction forces, and while the part near the blade remains untransported, the part near the sleeve is transferred to the sleeve side. The remaining layer becomes a substantial developing layer.

Therefore, the thickness of the developer can be formed into a thin layer about half the thickness of the ear cutting gap. It is understood that this means that the accuracy requirements for the ear cutting gap are more relaxed than in the past, and gap clogging becomes less likely to occur. Further, the ears of the developer magnetic brush located between the electret 42 and the sleeve 16 are in a fully extended state, and the density or concentration thereof is uniform, and the value of the density itself is also due to the density unevenness of the developer during stirring. It is not affected by density unevenness and remains almost constant. The fact that the density is uniform and that the density value takes a constant value is due to the effect described above. Further, the effect of setting the surface tension of the developing sleeve within the above-mentioned range is substantially the same.

(Embodiments) Hereinafter, preferred embodiments of the developing device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an explanatory diagram of the principle of the developing device used in the present invention, and the developing device of the present invention is not limited to such a structure.

FIG. 1 is an explanatory diagram of main parts of a developing device according to the present invention. As shown in FIG. 1, an electret dielectric layer 40 is formed on the outer surface of the doctor blade 20, and when the non-magnetic one-component developer 18 is negatively charged, for example, the electret layer 40 is formed on the outer surface of the doctor blade 20. Its outer surface is negatively charged in this case so that it has the same polarity of charge as the developer particles.

Also, the surface tension of the developing sleeve is 31 dyne/cm.
, especially at 25 dyne/cm or less. A bias potential of 200V to 1000V is applied to such a developing sleeve.

As the material for the electret, any organic, inorganic, or organic material can be used as long as it is a film-forming material that can be permanently polarized. In this respect, various polymeric materials are suitable. Suitable examples thereof include, but are not limited to, olefin resins such as polyethylene, polypropylene, ethylene-butene copolymers, ionically crosslinked olefin copolymers, and ethylene-acrylic copolymers; polyvinyl fluoride;
Polyvinylidene fluoride, vinyl fluoride/vinylidene fluoride copolymer, tetrafluoroethylene resin (PTFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA resin), tetrafluoroethylene-hexafluoride propylene copolymer Fluororesins such as polymer resins (FEP resins); Chlorine resins such as polyvinyl chloride and chlorinated polyolefins; Thermoplastic polyesters such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; Nylon 6, Nylon 12, Nylon 6.6, Polyamides such as nylon 6.10; various acrylic resins, etc. may be used alone or in combination of two or more.

Among these, fluororesins such as PTFE resin, PFAI resin, and FEP resin are preferred because they have good critical surface tension, good charge retention, and good durability.

Electret production is performed by applying any method known per se, such as thermal electretization method, electroelectretization method, radiation electretization method, photoelectretization method, etc., depending on the type of polymer used. . Thermal electretization method and electroelectretization method are advantageously applied to the above-mentioned polymers, especially fluororesins.

Further, in order to provide an electret layer on the surface of the doctor blade, a layer of a non-electret polymer film may be provided on the blade surface, and then this polymer film layer may be converted to an electret layer by the above-mentioned method.
Alternatively, the electret film may be bonded to the blade surface via an adhesive layer. The former method is generally advantageous.

In addition, the thickness of the electret layer is 0.005 to 2+
am, particularly in the range of 0.01 to 0.1 mm. The surface roughness of electret I'#42 is formed in the range of 0.02 to 2 μm, particularly 0.025 to 1 μm. The charge density (absolute value) of the electret layer is 5
10-10 to 2 x 10-''C/am2(7) range, especially I x 10-' to 1.5X 10-7c/c
+n2 range.

The gap D between the developing sleeve and the doctor blade is 0.05 to 2.0 mm, particularly 0.1 to 1.
．． It is desirable to set it to satisfy the range of 5.

With such a set width, the developer layer D' formed on the sleeve is formed thinner than D, and the developer layer D' is formed thinner than D.
It is possible to adjust the uniform layer thickness of ' to a minimum of 0.05 mm. The thickness of the developer layer D' of the magnetic brush is preferably in the range of 0.05 to 0.5 mm, although it depends on the type of developer. Further, in the present invention, the circumferential speed of the developing sleeve is generally preferably within the range of 5 to 100 CIIl/5eC1, particularly 10 to 80 cm/see.

In the present invention, the photoreceptor includes photoreceptors conventionally used in electrophotography, such as selenium photoreceptors, amorphous silicon photoreceptors, zinc oxide photoreceptors, cadmium selenide photoreceptors, cadmium sulfide photoreceptors, and various other photoreceptors. All organic photoreceptors etc. are used.

The non-magnetic one-component developer used in the present invention is one in which a colorant and a charge control agent, or further compounds known per se, are blended into a fixing resin medium. The developer used in the present invention is
It preferably has a volume resistivity of lXl0' to 3XIQ9Ωcm, especially 2 x 108 to 8 x 108Ωcm, and has a dielectric constant of 2.5 to 4.5, especially 3
．． It is desirable that it be in the range of 0 to 4.0.

The fixing resin medium, colorant, charge control agent and other compounding agents for the developer are preferably selected and combined so as to obtain the above characteristics. First, as the fixing resin medium, styrene #1 resin, acrylic resin, or styrene-acrylic copolymer resin is generally used.

The styrenic monomer used in these resins has the following formula (wherein, R1 is a hydrogen atom, lower (having 4 or less carbon atoms)
It is an alkyl group or a halogen atom, R2 is a substituent such as a lower alkyl group or a halogen atom, and n is an integer of 2 or less including zero. Examples of monomers represented by the following formulas include styrene, vinyltoluene, α-methylstyrene, α-chlorostyrene, vinylxylene, and vinylnaphthalene.

Among these, styrene is preferred.

On the other hand, as an acrylic monomer, (wherein R3 is a hydrogen atom or a lower alkyl group,
R4 is a hydrogen atom or an alkyl group having up to 18 carbon atoms.

), such as ethyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, acrylic acid, methacrylic acid, etc. In addition to the above-mentioned acrylic monomers, other ethylenically unsaturated carboxylic acids or their anhydrides,
For example, maleic anhydride, fumaric acid, maleic acid, crotonic acid, itaconic acid, etc. can also be used.

Styrene-acrylic copolymer resin is one of the suitable resin media, and the styrene monomer (A) and acrylic monomer (B) have a ratio of A:B=50:50 to 90. : 10, special! , : 60 : 40 to 85
: It is preferable to set it in the range of 15. Further, the resin used generally preferably has an acid value of O to 25. Further, from the viewpoint of fixing properties, it is preferable to have a glass transition temperature (Tg) of 50 to -0-R465°C.

As the coloring agent contained in the resin, the following inorganic or organic pigments, dyes, etc. may be used alone or in combination of two or more. Carbon black such as furnace blank and channel black; iron black such as triiron tetroxide; titanium dioxide such as rutile type or anatase type; phthalocyanine blue; phthalocyanine green; cadmium yellow; molybdenum orange; pyrazolone red; fast violet B, etc.

As the charge control agent, any charge control agent known per se may be used, such as oil-soluble dyes such as Nigrosine Base (CI50415), Oil Blank (CI26150), Subiron Black, or 1:1 type or 2:1 type. metal complex dye,
Naphthenic acid metal salts, fatty acids, soaps, resin acid soaps, etc. are used.

The particle size of the developer particles is 8 to 14 μm on a volume basis, especially 10 μm as measured by a Coulter counter.
What is the particle size?
It may be an amorphous material produced by the 8-melt mixing wire/pulverization method, or a spherical material produced by a dispersion or suspension polymerization method.

According to the present invention configured as described above, the non-magnetic-component charged developer 18 is regulated to some extent by the blade 2o, and the developer 18 passing through is not electrically charged from the electret layer 4o. receive repulsive force. The electret layer 40 provides a surface potential ES. As shown in FIG.
0 and compressed as much as possible. This is due to the electrical repulsive force of the electret 40 and the electrical attractive force of the sleeve 16 described above. Therefore, the developer layer located between the electret 40 and the sleeve 16 is compressed and becomes dense with no gaps, and its density or concentration becomes uniform. Further, the developer is compressed and its volume becomes smaller, and becomes 1 JyI, which is about half of the gap. As mentioned above, this makes the requirement for gap accuracy less strict, and also prevents the developer from adhering to the blade surface, thereby preventing gap clogging.

Further, since the spikes of the developer are always compressed and aggregated, the concentration or density of the developer passing through the sleeve 20 and the electret 40 takes a predetermined value. Since the concentration or density does not vary as in the conventional case, the width of the ear cutting gap must be adjusted in a sensitive manner, and there is a margin for the tolerance.

In addition, in this case, the surface tension of the developing sleeve surface is 3 l
If it is less than 25 dyne/cm, especially less than 25 dyne/cm, uncharged or oppositely charged toner due to van der Waals force or the like will not adhere to the developing sleeve, so that only sufficiently charged developer will be sent to the blade.

Therefore, the effect of the electret is sufficiently and uniformly received.

Figures 1 and 2 are explanatory diagrams of essential parts of a developing device used in the present invention, in which the electret layer is at a different polarity from the developer. As shown in FIG. 2, a plurality of electret dielectric layers 42 are formed on the outer surface layer of the doctor blade 20, and when the non-magnetic one-component developer 18 is negatively charged, for example,
In this case, the outer surface of the electret NI42 is positively charged so as to have a charge of opposite polarity to that of the developer particles.

Also, the surface tension of the developing sleeve is 31 dyne/cm.
, especially at 25 dyne/cm or less. A bias potential of 200V to 1000V is applied to such a developing sleeve.

Electret #42, which is the outermost surface, has a thickness of 0.
．． The surface roughness of the electret layer 42 is preferably in the range of 0.02 to 2 pm, particularly 0.025 to 1 μm. The charge density of the electret layer is 5 X 10-10
In the range from 2 x 10-'C/am2, especially 1 x 10
It is formed in the range of -9 to 1.5X 1O-7C/c2.

The surface potential ES of electret N42 is 200 to 10
0 ov, particularly preferably in the range of 300 to 900 square meters. In the present invention, the material of the electret layer and the method of applying the same are the same as those used in the apparatus shown in FIG. 2, and the same developing sleeve and photoreceptor are also used.

The gap D2 between the developing sleeve and the doctor blade, ie, the cutting gap D2, is desirably set within a range of 0.05 to 2.0 m, particularly 0.1 to 1.5 m. In such a setting section, the developer layer D2' formed on the sleeve is formed thinner than D2, and the uniform layer thickness of the developer layer D2' can be adjusted to a minimum of 0.05. Become. Further, as the non-magnetic one-component developer, the same one as mentioned above is used.

According to the present invention configured as described above, the -component-based charged developer 18 is regulated to some extent by the blade 20, and the developer 18A passing through it has spikes as shown in FIG. The sleeve 20 and the electret 42 are stretched as much as possible.

This is due to the electrical attraction force of the electret 42 and the magnetic attraction force of the sleeve 16 described above.

Therefore, the developer magnetic brush located between the electret 42 and the sleeve 16 is fully extended, and its density or concentration becomes uniform. Further, the developer becomes silent at approximately the midpoint of the ear cutting gap, forming a thin layer that is about half the width of the gap.

As mentioned above, this makes the requirement for gap accuracy less strict and prevents gap clogging.

Also, because the spikes of developer are always in an extended state,
The concentration or density of the developer passing through the sleeve 20 and the electret 42 takes a predetermined value. This is because the concentration or density does not vary as in the conventional case, so the adjustment of the radius of the ear cutting cap can be sensitively adjusted, and there is a margin for the tolerance.

Furthermore, since the surface tension of the developer sleeve is within a certain range, a sufficiently charged developer is delivered to the blade.
Fully exhibits the aforementioned effects.

The invention will be further illustrated by the following experimental examples.

Experimental Example 1 The electret layer of the blade is made of FEP resin, has a thickness of 0.025 mm, a surface roughness of 0.35 μm, a charge density of -4.5X 10-8c/crrf, a surface potential of -600 V, and a surface tension. was 19 dyne/an, and the polarity was the same as that of the developer.

Such a blade was attached to an improved electrophotographic copying machine DC-112C manufactured by Sanda Kogyo Co., Ltd., which uses an amorphous selenium photoreceptor, and transfer and fixing were performed under the following conditions.

The conditions are: The circumferential speed of the photoreceptor is 13. 5 cm/see, developing sleeve peripheral speed is 27 am/sec, photosensitive fiI/sleeve rotation method is forward direction, photosensitive layer sleeve problem NDo-
s is 0. 2mm, complementary gap 0.3mm
- Bias voltage 800V Also, a one-component non-magnetic developer was used as the developer (A type).

(1) The image density of the obtained copy was 1.32, and the fog density was 0.002.

(2) The developer layer (length of the spike) was 0.2 mm.

(3) Image density unevenness was 0.09 or less.

Experimental Example 2 The electret layer of the blade is made of FEP resin, has a thickness of Q25mm, a surface roughness of 0.275μm, and a charge density of 3. 7.times.10-ec/crrf, surface potential of 500 V, surface tension of 17 dyne/cm, and polarity opposite to that of the developer.

Such a blade was attached to an improved electrophotographic copying machine DC-112C manufactured by Sanda Kogyo Co., Ltd., which uses an amorphous selenium photoreceptor, and transfer and fixing were performed under the following conditions.

The conditions are: The circumferential speed of the photoreceptor is 13. 5 cm/sec, peripheral speed of the developing sleeve is 270 m/sec, photosensitive layer/sleeve rotation method is forward direction, photosensitive layer sleeve problem wID o-s is 0.15 mm,
Compensation gap is 0. 25 mm, bias voltage: 5 oov, surface tension of developing sleeve: A one-component non-magnetic developer was used as the developer.

(1) The image density of the obtained copy was 1.34, and the fog density was 0.003.

(2) The developer layer (length of the spike) was 0.15.

(3) Image density unevenness was 0.1 or less.

(Effects of the Invention) As explained above, according to the present invention, since the electret layer is provided on the doctor blade, the charged developer layer is located between the blade and the sleeve, and is exposed to electric attraction and magnetic attraction. Due to the action of force, the density becomes uniform and takes on a predetermined value. Therefore, the developer supplied to the support forms a thin layer with uniform density, and an excellent image without image unevenness can be provided during development. In addition, in this case, there is more margin in the accuracy of the ear cutting gap, making it easier to train the blade.
There is no possibility of fogging caused by excessive supply of developer.

Moreover, in this case, since the surface tension of the developing sleeve is set to a specific value, the above-mentioned effect becomes even more reliable.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts explaining the principle of an electrophotographic developing device according to the present invention. FIG. 2 is a sectional view of essential parts showing another embodiment of the developing device according to the present invention. 16...Developing sleeve, 20...Doctor blade, 22...Photoreceptor, 40.42...Electret dielectric layer.

Claims (1)

[Claims] (1) A support that supports an electrostatic image, a charging mechanism that charges a non-magnetic one-component developer, and a bias voltage applied to hold the charged developer on the surface by electrical attraction. It consists of a developer transporting member that transports the developer and applies the developer to the electrostatic image area of the support, and a developer amount regulating member that is close to the transporting member and regulates the amount of developer supplied. A developing device for a non-magnetic one-component developer, characterized in that the surface tension of the conveying member is within a range of 31 dyne/cm or less, and an electret dielectric layer is formed on the regulating member.