JPH0619371A - Method and device for forming electrophotographic image - Google Patents

Abstract

PURPOSE:To provide a novel electrophotographic image forming method for effectively increasing cleaning efficiency in an electrostatic fur brush system and executing excellent electrophotographic image formation. CONSTITUTION:The electrophotographic image forming method is one for adopting an electrophotographic image forming system for forming an electrostatic latent image in such a manner that a photosensitive photosensitive body 14 is uniformly charged, and a part to be visualized is irradiated with light, making the electrostatic latent image visualized by the electrostatically charged toner, and electrostatically transferring the obtained visual image on a transfer paper 2. As toner, one having <=3 dielectric constant is used, and a potential gradient for transferring residual toner 20 from the photosensitive body 14 to a fur brush 16, is generated between the non-electrical insulating fur brush 16 removing the residual toner 20 from the surface of the photosensitive body 14 and its surface, via the fur brush 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic image forming method and apparatus. The present invention can be used in optical printers and digital copying machines.

[0002]

2. Description of the Related Art In an optical printer or a digital copying machine, a photoconductive photoconductor is uniformly charged and then exposed so that a portion to be visualized is exposed to light to form an electrostatic latent image. . This electrostatic latent image is developed with toner charged to the same polarity or opposite polarity to the photoconductor, and the obtained visible image is electrostatically transferred onto transfer paper.

The toner forming the visible image formed on the photoconductor is not 100% transferred onto the transfer paper, and a considerable amount of toner remains on the photoconductor after the visible image transfer. It is necessary to clean the residual toner so that the residual toner does not affect the subsequent image forming process.

An electrostatic brush cleaning method using a fur brush or a magnet brush is known as one of the cleaning methods. In this cleaning method, toner is trapped in the brush by the action of an electric field to perform cleaning.

The toner forming the visible image formed on the photosensitive member is exposed to corona discharge having a polarity opposite to the original charging polarity at the time of electrostatic transfer, that is, the charging polarity at the time of development. The amount of charge per unit mass: Q / M is not constant, and in general, there are many cases where a uniform "plateau type" distribution is obtained in a relatively wide range.

Conventionally, there has been a problem that it is difficult to increase the cleaning efficiency of the electrostatic brush cleaning system due to the above-mentioned charged state of the residual toner.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to effectively enhance the cleaning efficiency of the electrostatic brush system and to perform good electronic image formation. The purpose of the present invention is to provide a simple electronic image forming method and apparatus.

[0008]

According to a first aspect of the present invention, there is provided an electronic image forming method, wherein a photoconductive photoconductor is uniformly charged, an electrostatic line image is formed by light irradiation, and the electrostatic line image is charged. Visualization is performed by electrostatically transferring the resulting visible image onto a transfer paper, and after the visible image is transferred, the residual toner remaining on the photoconductor is recharged to a predetermined polarity by a precharger and then the photoconductor is removed by the toner removing member. "A method of performing an electronic image forming method of removing from the surface", in which "a toner having a relative dielectric constant of 3 or less is used, and the toner remains on the surface of the photoconductor after the transfer of the visible image and on the surface of the photoconductor. A potential gradient for transferring the recharged residual toner from the surface of the photoconductor to the toner removing member is formed between the residual toner and the toner removing member that removes the residual toner from the surface of the photoconductor ". The "toner removing member" is the above-mentioned magnet brush or fur brush.

The polarity of recharge by the precharger may be the same as or opposite to the polarity at the time of developing the toner.

According to a second aspect of the present invention, "a photoconductive photoconductor is uniformly charged, an electrostatic ray image is formed by irradiation with light, and the electrostatic ray image is visualized by a charged toner to obtain a visible image. Is electrostatically transferred onto a transfer paper, and after the visible image is transferred, the residual toner remaining on the photoconductor is removed from the photoconductor surface by a toner removing member.
"As the toner, a toner having a volume average particle diameter: D _V and a number average particle diameter: D _P in a ratio of D _V / D _{P of 1} to 1.13 and a charge control agent uniformly dispersed is used. A potential gradient for transferring the residual toner from the surface of the photosensitive member to the toner removing member is formed between the surface of the photosensitive member and the toner removing member after the transfer of the visible image. "

According to a third aspect of the present invention, in the electronic image forming method according to the first or second aspect, "a toner has a volume average particle diameter: D _V and a number average particle diameter: D _P : D _V. /
D _P is in the range of 1 to 1.13, the charge control agent is uniformly dispersed, and the relative dielectric constant is 3 or less. "

According to a fourth aspect of the present invention, in an electronic image forming apparatus, "a photoconductive photoconductor is uniformly charged, and a portion to be visualized is exposed to light to form an electrostatic latent image. The image is visualized by dry development using toner charged to the same polarity as the photoreceptor, and the resulting visible image is electrostatically transferred onto transfer paper. "
It is a device that performs an electronic imaging method. That is, the toner is charged to "the same polarity as the potential of the photoconductor for forming an electrostatic latent image" and provided for development.

An electronic image forming apparatus according to a fourth aspect of the present invention includes a precleaning charger, a fur brush, and a potential gradient generating means. The "pre-cleaning charger" is applied with a discharge voltage obtained by superimposing an AC voltage on the DC voltage having the predetermined polarity in order to recharge the toner remaining on the surface of the photoconductor after the transfer of the visible image to the predetermined polarity. "Fur brush" is non-electrically insulating (volume electrical resistance is 10 ¹⁰ Ω
The residual toner, which is made of a material having a size of about cm or less), is brought into sliding contact with the surface of the photoconductor and recharged by the precleaning charger is removed from the surface of the photoconductor. The “potential gradient generating means” generates a potential gradient for transferring the recharged toner from the photoconductor to the fur brush via the fur brush. As the toner, “having a relative dielectric constant of 3 or less” is used as in the first aspect of the invention.

An electronic image forming apparatus according to a fifth aspect of the invention has the fur brush and the potential gradient generating means, and the toner has a ratio of volume average particle diameter: D _V and number average particle diameter: D _P : D _V. /
D _P is in the range of 1 to 1.13, and the charge control agent is uniformly dispersed in the toner.

Also in the electronic image forming apparatus according to claim 5, "after the visible image is transferred, the residual toner is recharged to a predetermined polarity before the residual toner is removed by the fur brush.
A "pre-cleaning charger to which a discharge voltage obtained by superimposing an AC voltage on a DC voltage having a predetermined polarity is applied" can be used (claim 6), and the "potential difference between the potential gradient generating means and the surface of the photoconductor" is from 200V to. It can be 700 V (claim 5). In the electronic image forming apparatus according to any one of claims 5 to 7, the particle diameter of the toner can be "7 µm or less" (claim 8), and the relative dielectric constant of the toner can be "3 or less" (claim). 9).

[0016]

As described above, after the transfer of the visible image, the charged state of the toner remaining on the surface of the photosensitive member is a "plateau type" in which the charge amount per unit mass: Q / M is uniform over a relatively wide range. In a distributed state, the charge amount of the toner particles is widely distributed around the average value.

Further, in the inventions of claims 1 and 4, the toner remaining on the surface of the photoconductor after the transfer of the visible image is recharged to a predetermined polarity by the precleaning charger. The charge amount is not uniform and generally has a mountain-shaped charge distribution with a wide half-value width, and toner that is charged more than the average charge amount and toner that is less charged are mixed.

In order to transfer the residual toner to the toner removing member such as the fur brush, the potential gradient formed through the member removes the residual toner from the surface of the photoconductor (mainly electric image force). Need to overcome. The potential difference that gives the potential gradient necessary to transfer the residual toner against the above-mentioned force to the toner removing member is called "removal bias".

If the removal bias is made sufficiently large, the residual toner strongly adhered to the photoconductor can be transferred to the toner removal member. However, if the potential gradient due to the removal bias becomes too large, the toner removal from the tip of the toner removal member will occur. Charge is injected towards the toner, resulting in "reverse charging" of the residual toner. The residual toner thus reversely charged is not removed from the surface of the photoconductor because it is repelled by the toner removing member, or adheres to the photoconductor again even if it is removed once.

The potential difference that gives a potential gradient such that the residual toner is reversely charged by the toner removing member as described above is called "background stain bias".

The inventors' research has revealed that the removal bias increases with an increase in the relative dielectric constant of the toner, and the background smear bias decreases with an increase in the relative dielectric constant of the toner.

It was also found that the "distribution width of the charge distribution in the residual toner" depends on the particle size distribution of the toner and the dispersion state of the charge control agent in the toner.

The powdery toner used for dry development is conventionally manufactured by the "crushing method", and the toner particle size distribution has a distribution width of the order of 10 μm. On the other hand, the “polymerization method” has become known recently.
The toner produced by the method has a narrow particle size distribution and has a ratio of volume average particle diameter: D _V and number average particle diameter: D _P : D _V / D
_P is about 1 to 1.13 and has a substantially uniform particle size, and the charge control agent is also dispersed uniformly. Such toner generally has a "narrow charge distribution" in the charged state.
Is known to have.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1B shows an "optical printer" which is an example of an electronic image forming apparatus to which the present invention can be applied. A photoconductive photoconductor 14 is provided in the main body indicated by reference numeral 1. The photoconductor 14 is formed in a drum shape and is driven to rotate clockwise. Around the photoconductor 14, a corotron 11a which is a pre-cleaning charger, a cleaning device 11, an optical writing device 12, a charger 13, a developing device 15, a resist roller 5, a transfer charger 6, a separation charger 7, a fixing device 8, and a discharge. Rollers 9 and the like are provided as shown.

The "imaging step" is performed as follows.
The photoconductor 14 rotates clockwise at a constant speed, and its peripheral surface is uniformly charged by the charger 13. The charging polarity is determined by the physical properties of the photoconductor, but here it is assumed to be negative. Writing is performed on the negatively charged surface of the photoconductor by an optical writing device. This writing is performed so that "a portion visualized by development" is irradiated with light.

The electrostatic latent image formed by writing is dry-developed by the developing device 15. The toner used for development has the same polarity as the photoconductor charged by the charger 13,
That is, it is negatively charged and selectively adheres to a portion where the surface potential is attenuated by light irradiation during writing.

The transfer paper 2 on which the visible image formed on the surface of the photoconductor 14 is transferred from the cassette 3 into the paper feed roller 4
Is fed by the registration roller 5 to the transfer portion at a proper timing, and is superimposed on the visible image on the photoconductor 14. In this state, the transfer charger 6 transfers a visible image onto the transfer paper 2 from the back side of the transfer paper 6 by performing corona discharge having a polarity opposite to that of the toner, that is, a positive polarity. Then, the separation charger 7 performs corona discharge with a discharge voltage obtained by superimposing an alternating current on a direct current having a polarity opposite to the discharge polarity of the transfer charger 6 to remove excess electric charge on the transfer paper 2 and remove the transfer paper 2 from the photoconductor 14. Separate.

The transfer paper 2 is then sent to the fixing device 8 to fix the visible image, and then the discharge roller 9 is used to form the tray 10.
Discharged on top. After the visible image transfer, the pre-cleaning charger 11a recharges the residual toner to a predetermined polarity, and the cleaning device 11 removes the residual toner from the surface of the photoconductor 14.

FIG. 1A shows a portion which is a feature of the invention in practicing the invention in the apparatus shown in FIG. 1B. The cleaning device 11 has a fur brush 16, which is a toner removing member, a bias roller 17, and a blade 18, in a housing.

The fur brush 16 comprises a brush-like acrylic carbon fiber having an original volume resistivity of 10 ⁵ to 10 ¹⁰ Ωcm, which is planted on a stainless steel roller having an outer diameter of φ10. The outer diameter of the outer peripheral portion of the brush is φ20. Then, the peripheral surface of the photoconductor 14 bites into the brush portion of the fur brush 16 by 0.5 to 2 mm. The bias roller 17 is a stainless steel roller having an outer diameter of φ12, and is 0.5 to the brush portion of the fur brush 16.
I'm eating ~ 2mm. The blade surface may be coated with a conductive resin such as Teflon containing carbon in order to enhance the toner removability by the blade 18.

In this embodiment, the bias roller 17
Is a "potential gradient generating means", to which a DC voltage is applied from the DC power supply 17a. Since the fur brush 16 is non-electrically insulating, the bias roller 17 that contacts the fur brush 16
The voltage from the bias roller 17 causes the photoreceptor 1
4, a potential gradient is generated via the fur brush 16 and the residual toner 20 is captured by this potential gradient. In addition, at the stage of contacting the fur brush 16,
Since the surface of the photoconductor in the image area is charged to -500 to -600V, the bias roller 1 is connected to the DC power supply 17a.
When a voltage of about -300 to +200 V is applied to 7, the bias roller 17 (potential gradient generating means) and the surface of the photoreceptor are +200 to +700 via the fur brush 16.
A potential gradient having a potential difference of V is formed.

The residual toner transferred from the photoconductor 14 to the fur brush 16 further transfers to the peripheral surface of the bias roller 17 according to the potential gradient. Urethane blade 18
Is held by a holding body 19, and the edge portion is in contact with the bias roller 17 in the “counter direction”, and the toner is scraped from the peripheral surface of the bias roller 17 to the bottom portion of the housing of the cleaning device. This toner is transported by the carrier 200.
Is collected by the collecting section.

The photoconductor 14, the bias roller 17, and the fur brush 16 all rotate clockwise. Photoconductor 1
4 and the rotation speed of the fur brush 16 is 1: 1, and the rotation speed of the fur brush 16 and the bias roller is 1 :.
It is 0.7-1: 1.

Now, a toner formed by the "crushing method" is prepared. The particle size distribution of this toner is as shown in FIG. When such a toner is used, the charging state of the toner remaining on the surface of the photoconductor after the transfer of the visible image is as shown in FIG. 2B, the charging amount per unit mass: Q /
M has a uniform "plateau" distribution over a wide range,
Positively and negatively charged toner is mixed.

An experiment was conducted in which the "pulverized toner" as described above was used to recharge the residual toner to a negative polarity by a precleaning charger. As shown in FIG. 2 (C),
When recharging was performed so that the average charge amount of the toner was −10 μc / g, all the residual toner could be recharged to the negative polarity. The charge amount at the peak of the "charge distribution" shown in FIG. 2C is determined mainly by the DC voltage component applied to the pre-cleaning charger 11a, and the AC component superimposed on this DC voltage component is the charge removal of the photoconductor. And play a role of narrowing the width of the toner charge distribution.

Looking at the charge amount distribution of FIG. 2C, there is still a large “variation” in the charge amount of each residual toner. Therefore, the magnitudes of the removal bias and the background smearing bias differ depending on the charge amount of the toner, and it is difficult to clean all the residual toner. That is, in order to remove the residual toner having a large amount of charge and "strongly bound to the photoconductor 14," the above-described removal bias must be increased. If this is done, the bias roller 17 and the surface of the photoconductor 14 will be removed. Therefore, the potential difference between and exceeds the background stain bias, and cleaning failure occurs due to reverse charging of the residual toner.

Next, using various toners having the same particle size distribution as the pulverized toner and different relative dielectric constants, the charge distribution of the residual toner after the recharge by the pre-cleaning charger and the change of the removal / background stain bias are performed. Was investigated by experiment. As a result, the following things became clear.

That is, the "charge distribution" was not so different from that in FIG. 2B even if the relative permittivity was changed, but the "removal bias" was as shown by the graph line 2-1 in FIG. 2D. The relative permittivity of the toner tends to increase linearly, and the “background stain bias” tends to decrease as the relative permittivity increases, as shown by the graph line 2-2.

The residual toner is satisfactorily removed in the region where the potential difference (corresponding to the vertical axis in FIG. 2D) giving the potential gradient is larger than the removal bias and smaller than the background stain bias. The larger the difference is, the larger the tolerance for the distribution width of the charge distribution is.

As is clear from the experiment, "the region where the potential difference that gives the potential gradient is larger than the removal bias and smaller than the background stain bias" is the region on the left side of the intersection of the graph lines 2-1 and 2-2, that is, the relative dielectric constant. Is an area of 3.7 or less.

In practice, however, the potential difference that gives the potential gradient is easily influenced by the environment such as temperature and humidity and the variation of the bias power source, and the variation is about ± 100 V. Therefore, the graph lines 2-1 and 2-2 are used. If the fluctuation of ± 100 V is allowed with respect to −2, the toner that is satisfactorily cleaned is that the relative permittivity is 3 or less (hatched area).

When a toner having a relative permittivity of 3 or more is used, the range of bias conditions for cleaning is small, so that the toner is easily affected by noise, and cleaning failure occurs in actual use. In an actual experiment, an extremely good cleaning effect was obtained especially for “a toner having a relative dielectric constant of about 2.7”. Of course, at this time, the residual toner needs to be recharged to a predetermined polarity (negative polarity in the example being described) by the pre-cleaning charger when it is cleaned by the fur brush. The recharging current value is "Drum current value (aluminum drum of the same diameter as the photoconductor 1 is installed in the device, the pre-cleaning charger is discharged under the same conditions as when discharging the photoconductor without rotating the drum, and the drum is grounded. Current flowing through) ”, AC / DC = 100V / −
The surface potential of the photoreceptor was 80 V and -950 V after recharging.

The above-described inventions of claims 1 and 4 are effective also in the case of an apparatus for forming a color image,
If the relative permittivities of the yellow, magenta, cyan, and black color toners are set to 3 or less and close to each other, it is possible to remove the residual components of these toners by the same toner removing member.

The data of various toners used in the above experiment are shown collectively in the column of "Amorphous (crushed toner)" in the chart of FIG. In order to make the relative dielectric constant of the toner within the above range, it is effective to reduce the content of carbon as a colorant or to color it with a dye without containing carbon. Amorphous color toner is generally manufactured by kneading a resin and a colorant at a resin melting temperature or higher, cooling, and then crushing and classifying with a mechanical or air collision crusher.

Next, using the toner produced by the "polymerization method",
The cleaning effect in the apparatus shown in FIG. 1 was examined.

Specific examples of toner production and coloring by the "polymerization method" include those disclosed in JP-A-4-243267. The toner produced by this method has a sharp particle size distribution and a uniform dispersion of the charge control agent, and is therefore suitable for the cleaning method used in the present invention.

As shown in FIG. 3A, this toner has an average particle diameter of 5 μm and a “substantially uniform” particle diameter.
About 1 to 3% by weight of wax is applied to the surface of the particles, and 0.1 to 3% of silica is added to the toner powder to improve fluidity. Data relating to this toner are shown in the column of "spherical shape (polymerized toner)" in the diagram of FIG.

An image forming process was carried out using this toner, and the charge distribution after the visible image transfer (before recharging by the precleaning charger) was examined.
It was as shown in (B).

As is clear from this figure, in the case of the toner manufactured by the polymerization method, the distribution of charge of the residual toner has a narrow distribution width even immediately after the transfer, and almost all the residual toner is charged to the same polarity. ing. Therefore, when such a toner is used, good cleaning can be performed by a toner removing member such as a fur brush “without recharging by a precleaning charger”.

As a result of recharging the above-mentioned residual toner to a positive polarity with a precleaning charger, as shown in FIG. 3C, all the residual toner was in a state of being substantially uniformly charged. Therefore, it is extremely easy to clean such recharged residual toner with a fur brush. According to an experiment by the inventor, as shown in FIG. 3C, a potential difference (a bias roller 17 as a potential gradient generating means and a photoconductor after the recharging) that gives a potential gradient necessary for cleaning the recharged residual toner. 14 potential difference) has a very wide tolerance range.

That is, referring to FIG. 3D, the toner having a wide particle size distribution manufactured by the "crushing method" (see FIG. 4) is used.
In the case of the "black B" toner in the chart of Fig. 2, in order to obtain a good cleaning effect, the "potential difference between the bias roller 17 and the surface of the photoreceptor 14 after recharging" is 200 to 30.
Although it is limited to the range of 0 V, the potential difference is 2 in the toner (polymerized toner in the chart of FIG. 4) manufactured by the “polymerization method”.
It was possible to obtain a very good cleaning effect in the range of 00 to 700V, particularly 300 to 600V. Further, this result was observed regardless of the particle size of the toner having a substantially uniform particle size formed by the polymerization method.

The current value for recharging by the precleaning charger at this time is AC / DC = 100V / -70V in the above-mentioned "drum current value", and the surface potential of the photoconductor after recharging is -700V. there were.

In the embodiment described above, the fur brush 1
Although 6 is electrically floated, the core roller of the fur brush 16 is also used as a potential gradient generating means in addition to the bias roller, and a voltage is forcibly applied to this, so that residual toner is transferred from the photoconductor to the fur brush through the fur brush. A potential gradient may be generated so as to transfer to the bias roller. When a voltage is applied to the core roller of the fur brush, the bias roller may be omitted and the toner in the fur brush may be removed from the fur brush by using, for example, a “baffle plate”.

In each of the above embodiments, the toner particle size distribution measurement is a value measured by a coulter counter. Further, in order to obtain a toner having "a substantially uniform particle size and a uniform dispersion of a charge control agent" used in claims 2, 3, 5 and 9, in addition to the "polymerization method", there is a method disclosed in U.S. Pat. No. 4,885. No. 350, "Dispersion Polymerization Method" and JP-A-53-17735.
The “suspension polymerization method” disclosed in the publication can be used.

The potential gradient generating means may utilize "friction charging", for example, the fur brush may be charged to a predetermined polarity by friction charging of the fur brush and the flicker. In this case, if the fur brush is made of completely electrically insulating material, the frictional charging potential of the fur brush will be increased without limit, and charge injection into the toner will occur. To be able to maintain.

[0056]

As described above, according to the present invention, a novel electronic image forming method and apparatus can be provided. Since this method and apparatus are configured as described above, it is possible to effectively clean the toner remaining on the photoconductor in the electronic image forming process and always realize good electronic image formation.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an optical printer that is an example of an electronic image forming apparatus to which the present invention can be applied and a cleaning unit thereof.

FIG. 2 is a diagram for explaining an embodiment of the invention described in claims 1 and 4 and its effect.

FIG. 3 is a diagram for explaining an embodiment of the invention described in claims 2, 5 and 9 and its effect.

FIG. 4 is a chart showing data of various toners described in connection with examples.

[Explanation of symbols]

 14 Photoreceptor 11a Pre-cleaning Charger 16 Fur Brush 17 Bias Roller

Claims (9)

[Claims] 1. A photoconductive photoconductor is uniformly charged, an electrostatic line image is formed by irradiation with light, the electrostatic line image is visualized by charged toner, and the obtained visible image is electrostatically transferred onto a transfer paper. After the transfer, and after the visible image transfer, the residual toner remaining on the surface of the photoconductor is recharged to a predetermined polarity by a precharger,
An electronic image forming method of removing from a photoreceptor surface by a toner removing member, wherein a toner having a relative dielectric constant of 3 or less is used, and a toner is removed between the photoreceptor surface and the toner removing member after the visible image transfer. ,
An electronic image forming method comprising forming a potential gradient for transferring recharged residual toner from a surface of a photoconductor to a toner removing member. 2. A photoconductive photoconductor is uniformly charged, an electrostatic line image is formed by light irradiation, the electrostatic line image is visualized by charged toner, and the obtained visible image is electrostatically transferred onto a transfer paper. An electronic image forming method in which residual toner remaining on the surface of the photoconductor after transfer and transfer of a visible image is removed from the surface of the photoconductor by a toner removing member, wherein the toner has a volume average particle diameter: D _V and a number Ratio of average particle size: D _P : D _V / D _P is in the range of 1 to 1.13, and a toner in which a charge control agent is uniformly dispersed is used. Between the members,
An electronic image forming method comprising forming a potential gradient for transferring residual toner from a surface of a photoconductor to a toner removing member. 3. The electronic image forming method according to claim 1, wherein the toner has a volume average particle diameter: D _V and a number average particle diameter: D _P of a ratio of D _V / D _P of 1 to 1. An electronic image forming apparatus characterized in that the charge control agent is uniformly dispersed in the range of 13 and the relative dielectric constant is 3 or less. 4. A photoconductive photoconductor is uniformly charged, and a portion to be visualized is exposed to light so as to form an electrostatic latent image, and the electrostatic latent image is made to have the same polarity as that of the photoconductor. An apparatus for performing an electronic image formation method in which a visible image obtained by dry development using a charged toner is visualized and electrostatically transferred to a transfer paper, and the residual toner remains on the surface of the photoconductor after the transfer of the visible image. A pre-cleaning charger to which a discharge voltage obtained by superimposing an AC voltage on the DC voltage of the predetermined polarity is applied in order to recharge the toner to a predetermined polarity, and the residual toner recharged by the pre-cleaning charger is removed from the surface of the photoconductor. A non-electrically insulating fur brush and a potential gradient generation for generating a potential gradient for transferring the recharged residual toner from the photoconductor to the fur brush through the fur brush. And means, as the toner, an electronic imaging device, characterized in that relative dielectric constant used as the 3 below. 5. A photoconductive photoconductor is uniformly charged, and a portion to be visualized is exposed to light so as to form an electrostatic latent image, and the electrostatic latent image is made to have the same polarity as that of the photoconductor. An electronic image forming device that visualizes a visible image by dry development with charged toner and electrostatically transfers the resulting visible image onto transfer paper. A non-electrically insulating fur brush to remove from the body surface, and
The toner has a potential gradient generating means for generating a potential gradient for transferring the residual toner from the photoconductor to the fur brush through the fur brush, and the toner has a volume average particle diameter: D _V and a number average particle diameter: A ratio with D _P : D _V / D _P is in the range of 1 to 1.13, and an electronic image forming device using a toner in which a charge control agent is uniformly dispersed. 6. The electronic image forming apparatus according to claim 5, wherein after the transfer of the visible image, prior to the removal of the residual toner by the fur brush, the residual toner is recharged to a predetermined polarity with an alternating voltage of a predetermined polarity. An electronic image forming apparatus comprising a pre-cleaning charger to which a discharge voltage having a voltage superimposed thereon is applied. 7. The electronic image forming apparatus according to claim 5 or 6, wherein the potential difference between the potential gradient generating means and the surface of the photosensitive member is 200 V or more.
An electronic image forming device characterized by being 700V. 8. The electronic image forming apparatus according to claim 5, 6 or 7, wherein the toner has a particle diameter of 7 μm or less. 9. The electronic image forming apparatus according to claim 5, 6 or 7 or 8, wherein the relative dielectric constant of the toner is 3 or less.