JPH0784467A - Image forming device - Google Patents

Abstract

PURPOSE:To provide a cleanerless image-forming device which outputs a satisfactory image at all times and reduces the generation of ozone. CONSTITUTION:The image forming device is provided with a toner image transfer means 17 for transferring a developed toner image to a recording medium, and clears up untransferred toner 22, remaining on the surface of a latent image holder after the transfer, by the use of a developing means 15. In the image forming device, the toner image transfer means 17 is composed of a conductive member to which a voltage in the range of -500V to -2000V is applied, a transfer belt 26 arranged in contact with the conductive member, and an attracting member for attracting the recording medium to the transfer belt 26. In the image forming device which is provided with a paper powder removal means for removing paper powder from the recording medium and clears up the untransferred toner 22 by the use of the developing means, the paper powder removal means is composed of a conductive member whose volume resistivity is 10<10>OMEGA.cm or below, to which a voltage in which an AC voltage of 300-1500Vpp is superimposed on a DC voltage of 100-2000V is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, and more particularly to an image forming apparatus for performing image recording without using a cleaning device for cleaning transfer residual toner.

[0002]

2. Description of the Related Art In an image forming apparatus based on an electrophotographic system, an image forming system in which a developing device collects toner in a developing device simultaneously with development without using a cleaning device for cleaning transfer residual toner (hereinafter referred to as a cleanerless image forming device). Method is adopted (for example, Japanese Patent Laid-Open No. 59-1).
33573, JP-A-59-157661). These publications disclose the basic idea of the cleanerless image forming method, and the outline thereof is summarized as follows. That is,
As shown in the cross-sectional view of the main configuration of FIG. 4, a well-known reversal development method is often used in an electrophotographic printer represented by a laser printer.

In the reversal development method, the toner 2 charged to the same polarity as that of the photoconductor 1 is used, and the toner 2 is attached to a portion of the surface of the photoconductor 1 where no electric charge exists (or a portion having a small amount of electric charge). The toner 2 is not attached to the portion where the electric charge exists. In order to realize such selective adhesion of the toner 2, the potential V ₀ of the charged portion and the potential V ₀ of the non-charged portion on the surface of the photoconductor 1 are set on the toner carrier (developing roller) 4 in the developing device 3. voltage between _l V _b (| V
_l | <| V _b | <| V ₀ |) is applied to suppress the adhesion of the toner 2 to the surface of the photoconductor 1 by the electric field between the charged portion and the electric field between the non-charged portion. The toner 2 is attached to the surface of the body 1.

Then, the toner 2 attached to the surface of the photoreceptor 1
Is transferred onto the surface of a recording medium (image support) 6 conveyed by, for example, a conveyor belt (not shown) by a well-known corona transfer device 5. In this transfer process,
Generally, all the toner 2 is not transferred, and the untransferred toner 2'is image-wise distributed on the surface of the photoconductor 1 after the transfer. In an ordinary electrophotographic apparatus (image forming apparatus), after the transfer residual toner 2'is collected by the cleaner 7 shown by the broken line, the photoconductor 1 is removed by the charge eliminating lamp 8.
The charges on the surface are removed, and the latent image forming process (uniform charging process by the charger 9 and exposure process by the light beam 10) is performed again.
In FIG. 4, 11 is a toner supply member (toner supply roller), 12 is a toner stirring bar that stirs the toner 2, and 13 is a toner layer thickness regulating member that regulates the toner layer on the surface of the toner carrier 4.

On the other hand, in the cleanerless recording apparatus (image forming apparatus), the transfer residual toner 2'is brought to the developing step without using the cleaner 7, and the transfer residual toner 2 is stored in the developing apparatus 3 simultaneously with the development. ′ Is collected. Strictly speaking, of the latent image formed by the exposure of the light beam 10,
The transfer residual toner 2'existing on the charged portion (that is, the unexposed portion or the non-image portion) is surely charged to the same polarity as the latent image by the charger 9, so that the toner is transferred from the toner carrier 4 to the photoreceptor 1. By the electric field that suppresses the transition of 2, that is, the electric field due to the potential difference between V ₀ and V _b ,
Transfers to the toner carrier 4 side. At the same time, the untransferred toner 2 ′ existing in the non-charged portion, that is, the exposed portion or the image portion, remains on the surface of the photoconductor 1 under the force from the toner carrier 4 toward the photoconductor 1. New toner particles 2 are transferred from the toner carrier 4 to this non-charged portion, and cleaning is performed simultaneously with development.

As described above, in the cleanerless image forming apparatus, since the cleaner 7 and the waste toner box for storing the cleaned toner, that is, the waste toner, are not required, it is easy to downsize and simplify the apparatus. Further, since the transfer residual toner 2'is collected by the developing device 3 and reused, waste toner is not generated and it is economical, and the photosensitive member 1 is not rubbed by a cleaning blade. Many merits are obtained such that the life of the photoconductor 1 can be extended.

[0007]

However, in this cleanerless image forming apparatus, fog may appear in an image due to the following reasons. That is, a well-known negatively chargeable organic photoconductor is used as a latent image carrier, and required charging, exposure, and reversal development are performed on the latent image carrier to form a visible image (toner image), and then this toner image is recorded on a recording medium. In the case of configuring the cleanerless image forming process based on the image forming process of transferring to, the negative charge type toner needs to be used as the toner. In this cleanerless image forming process, so-called fog toner adheres to the background portion of the image after long-term use, and the image quality is likely to deteriorate.

The inventors of the present invention have made extensive studies on the deterioration of image quality due to the fog toner, and as a result, have confirmed that it is based on the following reason. Generally, when the toner image is transferred onto the recording medium 6, the recording medium 6 is brought into close contact with the surface of the latent image carrier 1, so that the paper dust separated from the recording medium 6 tends to adhere to the surface of the latent image carrier 1. There is. Here, in the case of the configuration in which the surface of the latent image holding member 1 is cleaned by the cleaner 7 or the like, since the paper dust is removed by the cleaner 7, there are few problems. Then, it is collected in the developing device 3. By the way, usually, in the paper powder, fibers forming the paper and a binder for fixing the fibers are contained, and particularly when talc is used as the binder, the talc strongly rubs negatively. Since they are easily charged, when they are collected in the developing device 3 or on the surface of the developing roller 4, they are negatively charged by frictional charging with the toner, while they are positively charged. Then, the positively charged toner adheres to the background portion of the image, and the mixing of the paper dust causes fog.

When using a negative charging type photoreceptor,
Since the photoreceptor is charged by the negative corona discharge,
There is a problem that a large amount of ozone is likely to be generated, which adversely affects the human body. As a countermeasure against this ozone generation, it is possible to reduce the ozone generation by bringing a conductive brush or a conductive roller, to which a voltage is applied, into contact with the surface of the photoconductor to perform required charging. There is such a problem.
First, it is difficult to ensure that the transfer polarity of the transfer residual toner has a negative polarity. Therefore, it is unsuitable for the cleanerless process. Secondly, uneven charging occurs as compared with corona charging. There are problems such as difficulty in uniform charging of the body, and it is desired to solve or eliminate these problems. The difficulty of uniform charging is due to the fact that in the case of a conductive brush, the air discharge by the fibers constituting the brush is used, so that minute streak-shaped charging unevenness occurs, and when the roller is a conductive roller, The charging unevenness corresponding to the spatial variation of the electric resistance value of the material is generated.

The present invention has been made to solve the problems of the prior art as described above, and can always output a good image,
Moreover, it is an object of the present invention to provide a cleanerless image forming apparatus capable of reducing the generation of ozone.

[0011]

A first image forming apparatus according to the present invention comprises a latent image carrier, latent image forming means for forming a positive electrostatic latent image on the surface of the latent image carrier, and The electrostatic latent image is provided with a developing means for developing the toner with positively charged toner, and a toner image transferring means for transferring the developed toner image to a recording medium. In the image forming apparatus that cleans the transfer residual toner by the developing unit, the toner image transferring unit is
The present invention is characterized by comprising a conductive member to which a voltage of 500 to -2000 V is applied, a transfer belt arranged in contact with the conductive member, and a suction means for sucking a recording medium on the transfer belt. In a second image forming apparatus according to the invention, a latent image carrier, a latent image forming means for forming a positive electrostatic latent image on the surface of the latent image carrier, and the electrostatic latent image are positively charged. The latent image after the transfer is provided with a developing means for developing with toner, a toner image transferring means for transferring the developed toner image onto a recording medium, and a paper dust removing means for removing paper dust from the recording medium. an image forming apparatus for cleaning a transfer residual toner remaining on the carrier surface by the developing unit, the voltage the paper dust removal means is superimposed an AC voltage of 300 to 1,500 V _pp to a DC voltage of 100~2000V is applied volume resistance is 10 ¹⁰ · Wherein the cm and consists of the following conductive members.

[0012]

According to the present invention, in long-term image formation,
Even if the paper dust accumulates in the developing device, the binder such as the talc component in the paper dust is promoted to be negatively charged by itself and the toner is positively charged by friction, and the toner charged to the opposite polarity is originally Since the mixture in the positively charged toner is completely eliminated or avoided, a good image without fog can always be output. Further, by charging the latent image holding member by positive corona discharge or the like, it is possible not only to significantly reduce the generation of harmful ozone and also to perform uniform charging, but also in the cleanerless process. Since the transfer residual toner can be positively aligned to the positive polarity,
It is possible to always output high quality images without ghosts.

[0013]

Embodiments of the present invention will be described in detail below with reference to FIGS.

Embodiment 1 FIG. 1 is a sectional view showing a main part of a first configuration example of an image forming apparatus according to the present invention. In FIG. 1, 14 is an electrostatic latent image holding member, 15 is a developing device using a contact type one-component non-magnetic toner provided with an elastic developing roller 16, etc., 17 is a transfer device (transfer means), and 18 is transfer residual toner. Is a uniforming member for uniformly dispersing the electrostatic latent image, 19 is a charger for performing the required positive charging on the electrostatic latent image holding member 14, and 20 is a laser beam (exposure means) for forming an electrostatic latent image by exposure.

The structure of the image forming apparatus will be described in detail. First, the electrostatic latent image carrier 14 has a thickness of about 25 μm, which is formed by dispersing photoconductive powder in a binder having an electron transporting function, for example. It is a positive charging type organic photoconductor drum having a single-layer photoconductor. Here, instead of the positive charging type organic photoconductor drum 14, for example, an amorphous selenium photoconductor, an amorphous silicon photoconductor, or the like can be used.

A developing device using a two-component toner generally known as the developing device 15 or a developing device using a one-component magnetic toner is used. In this embodiment, a developing device using a contact type one-component non-magnetic toner provided with an elastic developing roller 16 is used. The developing roller (toner carrier) 16 is made of, for example, urethane rubber, silicone rubber, ethylene propylene rubber, NBR.
One with a conductive elastomer layer formed of a fluorine-based elastomer or urethane elastomer on the surface of an elastic layer such as rubber, one composed of only conductive rubber, one covered with a flexible conductive tube, and those Examples thereof include those having a positively chargeable hydrophobic silica powder adhered to the surface thereof. Further, it can be lost to mix a negative charge control agent or a metal into these, and the use of a negative charge control agent is particularly preferable. . Incidentally, the adhesion of the hydrophobic silica powder,
By arranging the auxiliary rollers facing each other, rubbing and rotating the outer peripheral surfaces of both rollers by interposing hydrophobic silica powder, and by additionally heating the roller surfaces at this time easily Can be attached.

Further, the developing device 15 includes a toner supply member (toner supply roller) 21 and a toner agitator 2 for agitating the toner 22.
3. A toner layer thickness regulating member 24 for regulating the toner layer on the surface of the toner carrier 16 is provided. Here, the toner supply body 21 is made of a negatively chargeable material, for example, fluorine rubber or urethane rubber, or a mixture of these with a negative charge control agent or metal, and a toner layer thickness regulating member. The reference numeral 24 also has a blade shape made of a negatively chargeable material, for example, fluorine rubber or urethane rubber, a mixture of these with a metal, or a metal plate. The toner layer thickness regulating member 24 is supplied with a DC bias, an AC bias, or an AC / DC superimposed bias by the power supply 25.
While pressing the surface of the toner carrier 16 which is rotated by applying 20 to 400 V, a toner layer having a substantially uniform thickness is formed.
It is formed on 16 surfaces, and the toner layer is brought into contact or non-contact with the latent image of the electrostatic latent image holding member 14 to perform reversal development. In this developing process, the toner 22 particles on the surface of the developing roller 16 must be positively charged in advance by contact with the toner supply roller 21, the developing roller 16 and the toner layer thickness regulating member 24. Therefore, the toner 22 is based on a binder resin such as styrene-based, acrylic-based, styrene-acrylic-based, polyester-based, which is easily frictionally charged positively, and has a positive charge control agent such as nigrosine or a complex salt (DuPont KK, CCA, An average particle size of 5 to 15 μm is selected by adding (such as PC-100).

Further, the transfer device 17 is, for example, a negative polarity type conductive roller or a conductive brush, and has a range of -500 to -500.
When a voltage of −2000 V is applied and the image developed on the surface of the developing roller 16 is transferred to the surface of a recording medium (transfer support / recording paper) conveyed by the transfer belt 26, for example,
Contributes to its transcriptional action. At the time of transfer by the transfer device 17, the recording medium is transferred to a transfer belt by a suction means such as a conductive brush or a conductive roller (not shown).
It is adsorbed and supported by 26. Here, the conductive transfer roller or transfer brush used as the transfer device 17 has an ozone generation amount of 1/100, as compared with the case where a negative corona charger is used.
The advantages are that it can be reduced to 10 or less, variation in transfer characteristics due to humidity change is small, and the absolute value of the transfer voltage can be set low.

Further, the residual toner uniformizing member 18 for uniformly dispersing the transfer residual toner 22 'is, for example, a static conductive brush or a rotary conductive brush, and is a DC voltage or a voltage obtained by superimposing an AC voltage on a DC voltage. The transfer residual toner 22 'is uniformly dispersed by the application of the
Thus, the electrostatic latent image carrier 14 and the electrostatic latent image carrier 14 are positively charged. Here, the voltage applied to the residual toner equalizing member 18 is a DC voltage of -100 to -800 V and a frequency of 300 to 10 kHz.
A negative AC voltage of 500 to 2000 V _pp or a voltage formed by superposing these is preferable, and a plurality of such residual toner uniformizing members 18 may be installed. If the absolute value of the voltage applied to the residual toner equalizing member 18 is less than the above range, the Coulomb force acting on the transfer residual toner is weakened and the uniformity is insufficient. The electric field strength may become excessively large, and the electrostatic latent image holder 14 (photoconductor) may be destroyed due to dielectric breakdown. On the other hand, in charging by the charger 19, for example, when a positive voltage of about 5 kV is applied to the corona wire of the charger 19, corona discharge is generated, and the surface 14 of the electrostatic latent image carrier is charged between 400 and 800 V. To be done.

In the next exposure step, the untransferred toner 22 'that has passed through without being exposed to light adheres to the area corresponding to the background portion of the latent image. Transferred to the surface side of 16 and collected in the developing device 15, at the same time, the toner 22 on the surface of the developing roller 16 is exposed on the exposed portion.
Is transferred to the latent image surface of the electrostatic latent image carrier 14 and required development is performed.

In the latent image forming / developing / transfer process, the electrostatic latent image holding member is separated from the recording medium in the transfer process.
The paper powder attached to the 14th surface is collected in the developing device 15, and the talc (calcium carbonate) component in the paper powder promotes positive charging of the toner. In other words, the talc component in the paper powder collected in the developing device 15 is likely to be negatively triboelectrically charged, so that in the negatively charged toner, the toner is positively charged and fog is likely to occur in the background portion. On the other hand, since the toner used is of the positive charging type, the mixing of the talc component warps the toner to become positively charged, and maintains a high-quality image output without fog for a long period of time. To do. For example, A4 size acidic paper containing a larger amount of talc than plain paper was used as the recording medium and 10,000 sheets were printed, but no increase in fog was observed. In addition, the amount of ozone generated by the positively charged corona in this image forming process was 1/20 that in the case of the conventional negative corona.

In this embodiment, it will be further described how to efficiently remove the paper dust and the like and whether a high quality image is output. In the conventional image forming apparatus, when the image is output for a long period of time, the paper powder adheres to the residual toner equalizing member 18, and the residual toner equalizing function tends to be impaired. On the other hand, as the residual toner uniformizing member 18, for example, when a roller-shaped conductive brush having a volume resistance of 10 ¹⁰ Ω · cm or less is rotated at a constant speed or intermittently, the residual toner 22 ′ is uniformized and negatively charged. The talc component, which is easily charged to the inside, is easily adsorbed and removed. In this case, the moving directions of the roller-shaped conductive brush and the electrostatic latent image carrier 14 at the contact positions are opposite to each other, and the speed ratio between them (peripheral speed of roller-shaped conductive brush / static speed). Peripheral speed of the latent image holding member 14), 0 (when intermittent rotation) ~ 3, preferably 0.5
Set to ~ 1.5. Here, if the speed ratio of both exceeds 3, the toner may be scattered from the conductive brush.
This is not preferable because it easily causes contamination in the device.

Further, in the present invention, it is desirable that the paper dust adhering to the recording medium is removed before the toner image is transferred onto the recording medium. That is, as shown in the cross-sectional view of the schematic configuration example in FIG. 2, the paper dust removing means 27 is arranged in the middle of the conveyance path conveyed to the transfer device 17 for transfer, and passes through the paper dust removing means 27. A configuration may be adopted in which paper dust adhering to the recording medium is removed at the stage. Note that the image forming apparatus illustrated in FIG. 2 has the same basic configuration as that illustrated in FIG. 1, and thus description of the other main configuration will be omitted.

Here, the paper dust removing means 27 functions as a paper dust removing roller 27a in which conductive fibers having a specific resistance value of 10 ¹⁰ Ω · cm or less are planted on the peripheral surface of the conductive shaft, and a counter electrode. Opposing rollers that also contribute to the conveyance of the recording medium
It is formed with 27b. In addition, the paper dust removing roller 2
The specific resistance value of the conductive fiber 7a is preferably selected from 10 ⁸ to 10 ¹² Ω · cm when the resistance value of the surface of the facing roller 27b is 10 ⁸ Ω · cm or more. The reason is that paper dust removing roller 2
This is to prevent the occurrence of overcurrent and sparks when the recording medium is not present between the 7a and the facing roller 27b, that is, when the two are in direct contact with each other. Practically, when the surface resistance value of the facing roller 27b is 10 ⁸ to 10 ¹³ Ω · cm, the resistance value of the conductive fiber of the paper dust removing roller 27a is preferably 10 ¹⁰ Ω · cm or less. In this image forming apparatus, the opposing roller 27b is grounded and a positive voltage is applied to the paper dust removing roller 27a. However, the paper dust removing roller 27a is set to a positive potential, and the potential difference between the two is 100 to 2000V. , Preferably from 500
Set to 1200V. More specifically, a zener diode having a desired voltage value is connected to the case of the charger 19, and a positive voltage of 100 to 2000 V is generated at one end of the zener diode by the current flowing from the corona wire into the case, and this is generated. Taking the configuration of connecting to the paper dust removing roller 27a,
It is also desirable in terms of simplification of the configuration. In order to obtain the desired effect, a positive DC voltage of 100 to 2000 V (preferably 100 to 800 V) is applied to the paper dust removing roller 27a.
Alternatively, the positive DC voltage of 100 to 2000 V and the frequency of 300 to
A voltage superposed with an AC voltage of 300 to 1500 V _pp of 50 kHz is applied. Here, when a voltage obtained by superimposing an AC voltage on a DC voltage is applied, the paper dust easily separates due to the vibration due to the AC electric field. When transferring with a transfer brush or transfer roller in the subsequent transfer process, the transfer device 17 and the electrostatic latent image carrier are
14 potential difference ΔV _T , paper dust removing roller 27a and opposing roller
When the relationship of the potential difference ΔV _R with 27b is set to satisfy ΔV _R ≧ 0.3 × ΔV _T, preferably ΔV _R ≧ ΔV _T , the amount of paper dust adhered to the electrostatic latent image carrier 14 is , It was possible to further reduce.

Further, in the structure shown in FIG. 2, the rotation speed and the rotation direction of the paper dust removing roller 27a can be set arbitrarily, but it is preferable that the rotation is such that the recording medium is rubbed,
Further, this rotation may be intermittent or stationary, so that a fixed brush may be used instead of the paper dust removing roller 27a. Further, it is desirable that the paper dust removing roller 27a and the like are detachable and are replaced as appropriate.

Embodiment 2 FIG. 3 is a cross-sectional view showing the main structure of an image forming apparatus according to another embodiment of the present invention, which is a case of a so-called color image forming apparatus. That is, the electrostatic latent image holder 14 shown in FIG. 1 or FIG. 2, the developing device 15 using the contact type one-component non-magnetic toner provided with the elastic developing roller 16 and the like, the transfer device (transfer means) 17, the rest. The toner uniformizing member 18 and the charger 1 for charging the electrostatic latent image holding member 14 with the required positive polarity.
9. Image units A, B, C, D comprising a laser beam (exposure means) 20 for forming an electrostatic latent image by exposure
Transfer belt 26 that also serves as a transport path for transporting the recording medium.
The color image forming apparatus has a basic configuration in which the color image forming apparatus is arranged in a line along the line. In the figure, 28 is a belt charger, 29
Is a belt cleaner and 30 is a paper feed roller. And
In this image forming apparatus, the color image developed by the image unit A is transferred to the surface of the recording medium by the transfer device of the image unit A, the recording medium is conveyed to the image unit B side, and the image unit B is transferred. In the image units C and D, the process of superposing and transferring the developed color image on the surface of the recording medium by the transfer device of the image unit B is sequentially performed in the same manner to output the desired color image.

In the above structure, each electrostatic latent image carrier 14
On the other hand, by charging with the positive corona, the amount of ozone generated was about 1/20 of that in the case where the negative charging type electrostatic latent image carrier was charged with the negative corona. Further, since the image units A, B, C, and D are subjected to reversal development using toner having a positive polarity, each transfer unit (apparatus) 17 has a conductive property capable of imparting a negative charge to the transfer belt 27. A conductive roller or a conductive brush is used. And the transfer belt
A voltage of -500 to -2000 V is applied to the conductive roller and the conductive brush in order to impart a negative charge to 26. Further, it is preferable that the belt charger 28 for negatively charging the outer surface of the transfer belt 26 is formed of a conductive roller or a conductive brush and a voltage of -500 to 200 V is applied. In this case, in order to give a sufficient negative charge to the inside of the transfer belt 26, the DC voltage applied to the conductive roller or the conductive brush has a frequency of 1 kHz or more, preferably 3 kHz.
It is preferable to superimpose an AC voltage of ˜10 kHz. Here, if the frequency is less than 1 kHz, the toner may vibrate during transfer to disturb the image, and if it exceeds 10 kHz, the effect of superimposing an AC voltage is insufficient. The AC voltage preferably has a peak value difference of 1 kV to 5 kV. That is, if the peak value difference of the AC voltage is less than 1 kV, the effect of superimposing the AC voltage is small, and if it exceeds 5 kV, the transferred image tends to be disturbed by the air discharge.

In forming the image, the recording medium is rewound from, for example, the paper feed roller 30, and transferred to the transfer belt 26.
A conductive brush or a conductive roller is arranged at a position to be fed toward the recording medium, and a negative charge is applied to the surface of the recording medium to electrostatically attract the recording medium to the surface of the transfer belt 27. Misalignment can be prevented.

In the embodiment, the case of using the non-magnetic one-component toner is illustrated, but the present invention can be applied to the developing method using the magnetic toner. Further, in the embodiment, the case where the development and the cleaning are performed at the same time has been described.
It is needless to say that the present invention can be applied to an image forming apparatus in which a process of performing only development and a process of performing cleaning by a developing device are appropriately switched. In this case, the untransferred toner is once collected by the uniformizing member (developing process), and then discharged and cleaned.

[0030]

As described above, according to the present invention, even in the cleanerless process, it is possible to minimize the influence of mixing of paper powder, and always output a good image without fog and a good image without ghost. You can On the other hand, on the other hand, there is an advantage that the generation of ozone, which may adversely affect the human body, can be suppressed to a small extent, which can be said to greatly contribute to the practical use and spread of this type of image formation.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a main part of an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing another example of the main configuration of the image forming apparatus according to the present invention.

FIG. 3 is a cross-sectional view showing still another example of the main configuration of the image forming apparatus according to the present invention.

FIG. 4 is a cross-sectional view showing a main part configuration of a conventional image forming apparatus. 1, 14 ... Electrostatic latent image carrier (photosensitive drum) 2, 22 ...
Toner 2 ', 22' ... Transfer residual toner (residual toner)
3, 15 ... Developing device 4, 16 ... Toner carrier (developing roller) 5, 17 ... Transfer device (transfer means) 6 ... Recording medium 7 ... Cleaner 8 ... Discharge lamp 9, 19 ... Charger
10, 20 ... Light beam (exposure means) 11, 21 ... Toner supply body (toner supply roller) 12, 23 ... Toner stirrer
13, 24 ... Toner layer thickness regulating member 18 ... Residual toner leveling member 25 ... Power supply 26 ... Transfer belt 27 ... Paper dust removing means 27a ... Paper dust removing roller 27b ... Opposing roller
28 ... Belt charger 29 ... Belt cleaner 30
... Paper feed roller

Claims (2)

[Claims] 1. A latent image carrier, latent image forming means for forming a positive electrostatic latent image on the surface of the latent image carrier, and developing means for developing the electrostatic latent image with positively charged toner. And an image forming apparatus for cleaning the residual toner remaining on the surface of the latent image holding member after transfer by the developing means, the toner image transferring means transferring the developed toner image onto a recording medium. The toner image transfer means is composed of a conductive member to which a voltage of -500 to -2000V is applied, a transfer belt arranged in contact with the conductive member, and a suction means for sucking a recording medium on the transfer belt. An image forming apparatus characterized by the above. 2. A latent image holding member, a latent image forming unit that forms a positive electrostatic latent image on the surface of the latent image holding member, and a developing unit that develops the electrostatic latent image with positively charged toner. A toner image transfer means for transferring the developed toner image onto a recording medium, and a paper dust removing means for removing paper dust from the recording medium, which remains on the surface of the latent image carrier after transfer. In the image forming apparatus for cleaning the untransferred toner by the developing means, the paper dust removing means applies a DC voltage of 100-2000V to 300-15%.
An image forming apparatus comprising a conductive member having a volume resistance of 10 ¹⁰ Ω · cm or less to which a voltage obtained by superimposing an AC voltage of 00 V _pp is applied.