JP2003330341A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which prevents image disturbance caused by a void phenomenon or toner slip phenomenon, has a high-performance cleaning means, and ensures high image quality. <P>SOLUTION: The image forming device has: photosensitive bodies; an intermediate transfer body onto which a toner image on each photosensitive body is primarily transferred, primary transfer means arranged corresponding to the photosensitive bodies so that the toner images of distinct colors are sequentially transferred on the intermediate transfer body, thereby superimposing the primary transfer images one on another, a secondary transfer means which secondarily transfers the primary transfer images on the intermediate transfer body to a transfer material, and a cleaning means which clears away the transfer residual toner on the photosensitive bodies. In the image forming device, the cleaning means holds magnetic powder with a metal roller incorporating a magnet and is actuated by bringing the magnetic powder into contact with the photosensitive bodies and, further, a lubricant is disposed so as to come into contact with the magnetic powder. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having an improved cleaning means for cleaning residual toner on a photosensitive member.

[0002]

2. Description of the Related Art In an image forming apparatus using an intermediate transfer member,
There is a step of transferring from a photosensitive member to an intermediate transfer member and from the intermediate transfer member to a transfer material as a final medium such as paper. In order to reduce ozone generation in each transfer process, in recent years, a roller transfer system is often used instead of the corona discharge system.

However, in the roller transfer method, since the intermediate transfer member is pressed against the photosensitive member on which the toner is adhered by the roller, the intermediate loss phenomenon is likely to occur due to the aggregation of the toner. Therefore, in the conventional roller transfer method using the intermediate transfer body, the intermediate transfer body is made to be an elastic body to prevent toner aggregation, or the pressing force of the transfer roller is reduced to prevent toner aggregation, or a lubricant is applied to the surface of the photoconductor. Was applied to facilitate the transfer of agglomerated toner lumps to an intermediate transfer member to prevent the intermediate loss phenomenon. However, each measure has its own problems. For example, in the case of an elastic intermediate transfer member, there is no problem at the beginning,
When the number of prints increases, there is a problem that the accuracy of toner-to-toner superposition deteriorates due to the expansion of the elastic body.

Further, the durability of the elastic body itself is shorter than that of resinous material, and the material is damaged. When the pressing force of the transfer roller is reduced, the nip length of the contact portion between the intermediate transfer member and the photosensitive member is shortened, the nip formation becomes unstable, and problems such as character dust and insufficient transferability occur. Furthermore, when applying a lubricant to the surface of the photoreceptor,
Although a developing device, a charging device, a static eliminator, a cleaning device and the like are arranged around the photoconductor, there is a layout problem that the lubricant applying mechanism cannot be arranged while arranging those devices.

Further, in the case of the tandem structure, it is necessary to coat the photoconductors of the respective colors with four, which leads to an increase in cost. As described above, it is impossible to solve the phenomenon of the middle missing phenomenon, the character dust and the phenomenon of insufficient transfer without causing other problems.

Further, recently, in order to further improve the image quality, the particle size of the toner has been reduced. Further, a toner by a polymerization method has been developed in order to stabilize the shape of a toner having a small particle size. These can achieve improvement in image quality, and besides, the charge amount can be stably controlled, so that development and transferability are improved. Furthermore, there is an advantage that the toner consumption can be reduced.

[0007]

However, the toner having a smaller particle size and the toner produced by the polymerization method all deteriorate the cleaning property. In order to solve this, conventionally, a brush and an elastic roller for rubbing are arranged on the upstream side of the cleaning blade to assist the cleaning. However, there is a limit to these means, and if the charge amount of the toner rises more than expected or if the printing rate is larger than expected, the phenomenon of toner slipping from the blade occurs in all cases. In such a case, a toner slip-through line is printed on the image. As described above, the toner has a small particle size and the cleaning property of the toner by the polymerization method is not sufficient.

The present invention eliminates the drawbacks of the prior art and increases the charge amount of the toner, and even when the printing rate is larger than expected, a phenomenon such as a middle missing phenomenon and a toner slippage, and further It is an object of the present invention to provide an image forming apparatus which has improved cleaning means and which can obtain high image quality so as not to cause image irregularity due to the phenomenon of insufficient transfer of character dust.

[0009]

This object is achieved by any of the following technical means (1) to (14).

(1) Each photoconductor, an intermediate transfer member to which the toner image on each photoconductor is primarily transferred, and a toner image of each color are sequentially transferred on the intermediate transfer member to superimpose each primary transfer image. A plurality of primary transfer means arranged corresponding to the respective photoconductors so as to be aligned, a secondary transfer means for secondarily transferring the primary transfer image on the intermediate transfer body onto a transfer material, and In an image forming apparatus having a cleaning unit for cleaning the transfer residual toner on the photosensitive member, the cleaning unit holds a magnetic powder by a metal roller rotatably supported by a fixed shaft containing a magnet, and the magnetic powder The attached toner is cleaned by contacting the
An image forming apparatus further comprising a lubricant disposed so as to come into contact with the magnetic powder.

(2) The image forming apparatus according to item (1), wherein the toner of the toner image is used together with a carrier to form a two-component developer.

(3) The image forming apparatus according to item (1) or (2), wherein the cleaning means applies a bias to the metal roller to electrically attract the metal roller.

(4) The image forming apparatus according to any one of (1) to (3), wherein the lubricant is a solid lubricant.

(5) The image forming apparatus according to any one of items (1) to (3), wherein the lubricant is a powdery lubricant.

(6) The toner of the toner image has a number average particle size of 3 to 8 μm (1) to
The image forming apparatus according to any one of (5).

(7) The image forming apparatus according to any one of items (1) to (6), wherein the photoconductor has a drum shape.

(8) The secondary transfer means to the transfer material is
An intermediate transfer member as an image carrier, a backup roller sandwiching the intermediate transfer member, and a secondary transfer roller, and the backup roller has a resistance value of 1 × 10 ⁵ to 1 × 10 ⁷ Ω. Resistance value of 1 × 10 ⁵ to 1 × 1
The image forming apparatus according to any one of items (1) to (7), which has a constant current control of 0 ⁷ Ω.

(9) The toner has a variation coefficient of shape coefficient of 16% or less, and a variation coefficient of number in number particle size distribution of 27% or less (1) to (8).
The image forming apparatus according to any one of items.

(10) The relative position of the primary transfer means from the photosensitive member to the intermediate transfer member is within 10 mm in the rotational direction upstream and downstream from the center point of the contact area between the photosensitive member and the intermediate transfer member. The image forming apparatus according to any one of items (1) to (9).

(11) The position of the primary transfer roller as the primary transfer means is located downstream of the contact start point of the intermediate transfer body and the photoconductor in the traveling direction of the intermediate transfer body (1) to ( The image forming apparatus according to any one of items 10).

(12) The relative position of the secondary transfer roller as the secondary transfer means when the primary transfer image on the intermediate transfer body is secondarily transferred to the transfer material is the intermediate transfer body and the backup roller. The image forming apparatus according to any one of (1) to (11), wherein the distance is within 20 mm on the upstream side and the downstream side in the rotation direction with respect to the center point of the contact area with.

(13) The plurality of photoconductors have respective developing means corresponding thereto (1) to (1)
The image forming apparatus according to any one of 2).

(14) The intermediate transfer member is a semiconductive resin having a volume resistivity of 1 × 10 ⁴ to 1 × 10 ¹² Ω · cm, which is one of the items (1) to (13). The image forming apparatus according to item.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. Note that the description in this section does not limit the technical scope of the claims or the meaning of terms. Further, the following affirmative description in the embodiments of the present invention shows the best mode, and does not limit the meaning or technical scope of the terms of the present invention. For example, in the following embodiments, the intermediate transfer member is described as an endless belt-shaped intermediate transfer member 70,
Sometimes it is simply an intermediate transfer member. Incidentally, the intermediate transfer member may have a cylindrical shape, but in the present embodiment, an endless belt shape will be described.

FIG. 1 is a sectional view showing an embodiment of the image forming apparatus of the present invention. This color image forming apparatus is called a tandem type color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C and 10.
K, an endless belt-shaped intermediate transfer body unit 7, a sheet feeding and conveying means 21 and a fixing device as a fixing means 24. A document image reading device SC is arranged above the main body A of the image forming apparatus.

Image forming section 1 for forming a yellow image
0Y is a drum-shaped photoconductor 1 as a first image carrier.
Y, a charging unit 2Y arranged around the photoconductor 1Y, an exposing unit 3Y, a developing unit 4Y, a primary transfer roller 5Y as a primary transfer unit, and a cleaning unit 6Y. The image forming unit 10M that forms a magenta image includes a drum-shaped photoconductor 1M as a first image carrier, a charging unit 2M arranged around the photoconductor 1M, an exposing unit 3M, a developing unit 4M, It has a primary transfer roller 5M as a primary transfer means and a cleaning means 6M. The image forming unit 10C that forms a cyan image includes a drum-shaped photoconductor 1C as a first image carrier, a charging unit 2C arranged around the photoconductor 1C, an exposing unit 3C, and a developing unit 4C. It has a primary transfer roller 5C as a primary transfer means and a cleaning means 6C. The image forming unit 10K that forms a black image is the first
Drum-shaped photoconductor 1K as an image carrier of the above, and the photoconductor 1
Charging means 2K, exposure means 3K, developing means 4K, and primary transfer roller 5 as primary transfer means arranged around K.
K, cleaning means 6K.

The endless belt-shaped intermediate transfer body unit 7 is a semi-conductive endless belt-shaped second image carrier, which is wound around a plurality of rollers and is rotatably supported. Have.

Image forming units 10Y, 10M, 10C, 10
The image of each color formed by K is transferred to the primary transfer roller 5Y,
By 5M, 5C, and 5K, the color images are sequentially transferred onto the rotating endless belt-shaped intermediate transfer member 70 to form a combined color image. The transfer material P as a recording medium accommodated in the paper feed cassette 20 is fed by a paper feed means 21, passes through a plurality of intermediate rollers 22A, 22B, 22C, 22D, and a registration roller 23, and serves as a secondary transfer means. Then, the color image is collectively transferred onto the transfer material P by being conveyed to the position of the secondary transfer roller 5A. Transfer material P on which a color image has been transferred
Is subjected to a fixing process by the fixing means 24, and the paper discharge roller 25
The sheet is sandwiched between the sheets and placed on the sheet discharge tray 26 outside the machine.

The above describes the state in which an image is formed on one side of the transfer material P. In the case of double-sided copying, the paper discharge switching member 170 is switched, the paper guide portion 177 is opened, and the transfer material P is transferred. It is conveyed in the direction of the dashed arrow.

Further, the transfer material P is conveyed downward by the conveying mechanism 178 and is switched back by the paper reversing portion 179, and the rear end portion of the transfer material P becomes the leading end portion and is fed into the double-sided copying paper feeding unit 130. Be transported.

The transfer material P is a paper feed unit 130 for double-sided copying.
The conveyance guide 131 provided at the position is moved in the paper feed direction, the transfer material P is re-fed by the paper feed roller 132, and the transfer material P is guided to the conveyance path 22.

As described above, the transfer material P is again conveyed to the position of the secondary transfer as described above, the toner image is transferred to the back surface of the transfer material P, and the fixing means 24 fixes the toner image.
Paper is discharged to 6.

After the color image is transferred onto the transfer material P by the secondary transfer roller 5A as the secondary transfer means, the endless belt-shaped intermediate transfer body 70 in which the transfer material P is curvature-separated is removed by the cleaning means 6A. Are removed.

During the image forming process, the primary transfer roller 5K is constantly in pressure contact with the photoconductor 1K. Other primary transfer roller 5
Y, 5M and 5C are pressed against the corresponding photoconductors 1Y, 1M and 1C only when forming a color image.

Secondary transfer roller 5A as secondary transfer means
Is pressed against the endless belt-shaped intermediate transfer member 70 only when the transfer material P passes through here and secondary transfer is performed.

Further, the housing 8 can be pulled out from the main assembly A of the apparatus through the support rails 82L and 82R.

The casing 8 is composed of the image forming units 10Y, 10M, 1
0C, 10K and an endless belt-shaped intermediate transfer body unit 7.

Image forming units 10Y, 10M, 10C, 10
The Ks are arranged in a column in a substantially vertical direction. Photoconductor 1
An endless belt-shaped intermediate transfer body unit 7 is arranged on the left side of Y, 1M, 1C and 1K in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes a driving roller 72 and a driven roller 7.
1 and 73, an endless belt-shaped intermediate transfer body 70 as an intermediate transfer body that can be rotated by winding a backup roller 74, primary transfer rollers 5Y, 5M, 5C and 5K, and cleaning means 6A.

When the housing 8 is pulled out, the image forming portions 10Y, 10M, 10C and 10K and the endless belt-shaped intermediate transfer body unit 7 are pulled out from the main body A as a unit.

The support rail 82L on the left side of the casing 8 in the drawing is
It is arranged on the left side of the endless belt-shaped intermediate transfer body 70 in the space above the fixing means 24. The support rail 82R on the right side of the casing 8 in the figure is disposed near the lowermost developing unit 4K. The support rail 82R includes the developing means 4Y, 4
The M, 4C and 4K are arranged at positions where they do not interfere with the operation of attaching and detaching the M, 4C and 4K.

Further, on the upstream side of the transfer portion from the photoconductors 1Y, 1M, 1C, 1K to the endless belt-shaped intermediate transfer body 70, as shown in FIG.
As also shown, a nip forming roller 76 that presses from the inside of the endless belt-shaped intermediate transfer member 70 toward the photoconductors 1Y, 1M, 1C, and 1K is provided to adjust the nip formation amount between the intermediate transfer member and the photoconductor. I can do it.

That is, in the image forming apparatus of the present invention, the endless belt-shaped intermediate transfer member 70 to which the toner images on the photosensitive members 1Y, 1M, 1C and 1K are primarily transferred, and the toner image of each color on the intermediate transfer member are transferred. A plurality of primary transfer rollers 5Y, 5M, 5C and 5K arranged corresponding to the respective photoconductors so that the primary transfer images are superposed on each other, It has a secondary transfer roller 5A for secondarily transferring the transferred image onto the transfer material P and a cleaning means 6A for cleaning the transfer residual toner after the secondary transfer on the endless belt-shaped intermediate transfer member 70.

Next, the structure of the cleaning means 6Y, 6M, 6C, 6K for the photoconductors 1Y, 1M, 1C, 1K, which is a major feature of the image forming apparatus of the present invention, will be described.

FIG. 4 is a side sectional view of the cross sectional view of FIG.
As shown in, cleaning means 6Y, 6M, 6C, 6
K is an aluminum metal roller 62 having an outer diameter of 20 mm.
Is rotatably provided around a fixed shaft 61 in which a 4-pole magnet 61 is arranged, and the surface of the metal roller 62 is roughened by plasma spraying. Magnetic powder has a diameter of 50 μm
It is about 100g of ferrite powder,
A magnetic brush 67 having a shape as shown in FIG. 3 is formed by being held by the metal roller 62 made of aluminum. The amount D of bite into the magnetic powder is about 1 mm, and the solid lubricant 63 (Zn-St, 100%) is, for example, 5 × 5 × 35.
It is attached to a lubricant fixing slider 65 with a size of 0 mm, and is pushed by a spring 66 so that it can slide along the inner wall of a spring box 64. Such a lubricant fixing slider 6
As shown in FIG. 4, 5 is attached at two symmetrical positions. The pressing force of the solid lubricant 63 on the magnetic brush is 0.49 to 9.8N.

Instead of the solid lubricant 63, a powdery lubricant may be placed and placed in a case having the same size as the solid lubricant 63. However, the surface of the case that comes into contact with the magnetic brush is provided with mesh pores having a size approximately the same as the powder particle diameter.

Further, by biasing the metal roller 62, the suction force of the waste toner can be further increased electrically.

In this way, the residual toner on the photoconductor is efficiently collected in the cleaner box 60 by the magnetic brush 67. Then, the lubricant is applied to the surface of the photoconductor through the magnetic brush 67 to improve the releasability,
During the subsequent image formation, the aggregated toner is not transferred to the photoconductor and all is temporarily transferred to the endless belt-shaped intermediate transfer member, so that phenomena such as intermediate missing phenomenon, toner slipping through, character dust, and insufficient transferability do not occur at all. High quality images can be obtained.

Further, in such an image forming apparatus of the present invention, the toner used in the construction of the developing means employs a two-component developer together with the carrier, but the construction of the developing means and the developer are the same as those in the present embodiment. It is not limited.

The number average particle diameter of the toner of the toner image used in the image forming apparatus of the present invention is preferably 3 to 8 μm in view of image quality and toner consumption.

The photosensitive member of the image forming apparatus of the present invention is preferably drum-shaped because it has good processing accuracy and is easy to manufacture.

In the image forming apparatus of the present invention, the secondary transfer means to the transfer material comprises an intermediate transfer member as an image carrier, a backup roller sandwiching the intermediate transfer member, and a secondary transfer roller. The resistance value of the roller is 1 × 10 ⁵ to 1 × 10 ⁷ Ω, the resistance value of the secondary transfer roller is 1 × 10 ⁵ to 1 × 10 ⁷ Ω, and constant current control is performed. As a result, almost no ozone is generated, and repelling does not occur, which is preferable.

The toner of the toner image used in the image forming apparatus of the present invention has a variation coefficient of shape coefficient of 16% or less, and a variation coefficient of number in number particle size distribution of 27% or less. It is preferable in terms of quantity.

In the image forming apparatus of the present invention, the relative position of the primary transfer means from the photoconductor to the intermediate transfer body is as shown in the schematic diagram of FIG. It is preferable to be within 10 mm from the center point of the contact area with respect to the rotational direction upstream and downstream, because the contact condition between the photoconductor and the intermediate transfer member is uniform and good, and the transfer property is stable.

[0054]

[Table 1]

However, in the image forming apparatus of the present invention, from the viewpoint of occurrence of the character dust phenomenon, Table 1 is the same.
As shown in, the position of the primary transfer roller as the primary transfer means is preferably located downstream of the contact start point of the intermediate transfer member and the photosensitive member in the moving direction of the intermediate transfer member.

In the image forming apparatus of the present invention, the relative position of the secondary transfer roller as the secondary transfer means when the primary transfer image on the intermediate transfer member is secondarily transferred to the transfer material is It is preferably within 20 mm on the upstream side and the downstream side in the rotational direction with respect to the center point of the contact area between the intermediate transfer member and the backup roller. That is, the pressing force of the secondary transfer roller 5A against the intermediate transfer member is close to 10 times the pressing force of the primary transfer roller against the photosensitive member, and the nip amount is large. Also, the contact condition is uniform and the transferability is good for a distance of 20 mm downstream, which is preferable.
As shown in (4), the result is that the upstream side is not preferable and the downstream side is desirable.

[0057]

[Table 2]

In the image forming apparatus of the present invention, the plurality of photoconductors have respective developing means corresponding thereto.

In the image forming apparatus of the present invention, the intermediate transfer member has a volume resistivity of 1 × 10 ⁴ to 1 × 10 ¹² Ω · c.
As shown in Table 3, the semi-conductive resin of m is preferable from the viewpoint of preventing cissing due to charge leakage and ozone due to discharge.

[0060]

[Table 3]

Next, an example of an embodiment in which the image forming apparatus of the present invention is operated will be described. Embodiments The following are the required specifications of a tandem type intermediate transfer type full-color copying machine which is an image forming apparatus of the present invention.

L / S is 180 mm / s. Photoconductor 1
The drum diameters of Y, 1M, 1C, and 1K were 60 mm, and as the organic semiconductor layer, a phthalocyanine pigment dispersed in polycarbonate was applied. The thickness of the photosensitive layer including the charge transport layer was 25 μm.

The potentials of the non-image parts of the photoconductors 1Y, 1M, 1C and 1K are detected by a potential sensor and feedback-controlled (controllable range is -500V to -900V), and the total exposure potential is -50 to 0V. .

A semiconductor laser (LD) was used and the output was set to 300 μW so that the exposure was performed by a laser scanning method.

The development was a two-component development system. The intermediate transfer member was an endless belt-shaped intermediate transfer member 70, and a seamless semiconductive resin belt (volume resistivity: 1 × 10 ⁸ Ω · cm) was used.

Primary transfer roller 5 as primary transfer means
For Y, 5M, 5C, and 5K, a foaming roller (outer diameter 20 mm, resistance value 1 × 10 ⁶ Ω) was installed on the back surface of the endless belt-shaped intermediate transfer member 70 as the primary transfer, and constant current control of 20 μA was performed.

As the transfer roller 5A, a semiconductive roller was pressed against the endless belt-shaped intermediate transfer member 70 from the back surface of the transfer material P as a secondary transfer means, and a constant current control of 80 μA was performed.

For fixing, roller fixing in which a heater is arranged inside the fixing means 24 is used. Endless belt-shaped intermediate transfer member 70
The distance between the upper photoconductor and the next color photoconductor was set to 95 mm.

The endless belt-shaped intermediate transfer member 7 together with the tension roller 71, the driving roller 72 and the secondary transfer roller 5A.
The outer diameter of the backup roller 74 sandwiching 0 is 31.
6 mm (95 mm / 3).

Primary transfer roller 5Y, which is a primary transfer means,
The outer diameter of 5M, 5C and 5K was set to 20 mm.

The tension of the endless belt-shaped intermediate transfer member 70 was set to 49N. Primary transfer rollers 5Y, 5M, 5C, 5
The pressing force of K was set to 4.9N.

The toner concentration in the developing device as the developing means was 4% by mass. In the cleaning means 6Y, 6M, 6C, 6K shown in the cross-sectional configuration diagram of FIG. 3, an aluminum metal roller 62 having an outer diameter of 20 mm is rotatable around a fixed shaft 61 in which a 4-pole magnet 61 is arranged. The surface of the metal roller 62 is roughened by plasma spraying. The magnetic powder is ferrite powder having a diameter of about 50 μm, and about 100 g of the magnetic powder is held on the aluminum metal roller 62 to form a magnetic brush 67 as shown in FIG. The amount D of bite into the magnetic powder is about 1 mm, and the solid lubricant (Zn-St, 100%) 5 × 5
Place x 350 mm.

A test of 200,000 copies was conducted with the above configuration. As a result, over 200,000 copies, there was no problem in terms of image such as middle loss, slip-through, a phenomenon of insufficient transfer of character dust and poor cleaning.

[0074]

According to the present invention, the drawbacks of the prior art are eliminated, and even if the charge amount of the toner is increased or the printing rate is larger than expected, a phenomenon such as a middle missing phenomenon, a toner slip through, and a character It has become possible to provide an image forming apparatus capable of obtaining high image quality, which has a cleaning unit that does not cause image disturbance due to the phenomenon of dust and insufficient transferability and does not cause cleaning failure.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram illustrating a color image forming apparatus according to an example of an embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram showing an arrangement of nip forming rollers when a toner image is transferred from a photoconductor to an intermediate transfer body.

FIG. 3 is a cross-sectional configuration diagram showing a cleaning unit for a photoconductor using a magnetic brush.

FIG. 4 is a side sectional view of FIG.

FIG. 5 is a schematic diagram showing a positional relationship among a photoconductor, an intermediate transfer body, and a primary transfer roller.

[Explanation of symbols]

1Y, 1M, 1C, 1K photoconductor 5Y, 5M, 5C, 5K Primary transfer roller 5A Secondary transfer roller as secondary transfer means 6Y, 6M, 6C, 6K Cleaning means 24 Fixing means 60 cleaner box 61 magnet 62 metal roller 63 Solid lubricant 64 spring box 65 Lubricant fixed slider 66 spring 67 Magnetic Brush 70 Endless belt-shaped intermediate transfer member 74 Backup roller 76 Nip forming roller

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/16 G03G 21/00 316 103 9/08 361 (72) Inventor Hiroshi Morimoto Ishikawacho, Hachioji, Tokyo 2970 Konica stock company (72) Inventor Masashi Saito 2970 Ishikawa-cho, Hachioji-shi, Tokyo F-term inside Konica stock company (reference) 2H005 AA15 AA21 DA07 EA05 FA01 2H134 GA01 GB02 HC01 HC02 HC05 HC06 HC12 HC14 JB02 KB02 KB13 KD02 KD13 KF03 KG03 KH01 KJ02 LA01 2H200 FA08 FA17 FA18 FA19 GA12 GA14 GA16 GA23 GA34 GA45 GA47 GB14 GB25 HA03 HB12 HB22 HB46 HB48 JA02 JA03 JA26 JA28 JC04 JC16 LA15 LA40 LB13 MB04 MB06 NA02 PA30 2H300 EB03 EF16 EJ08H08EF01 EC02 EF08 EF01 EF04 EF12 EC02 EC02 EF08 EF01 EJ50 EJ51 EL02 FF05 GG01 GG02 GG29 GG46 GG48 HH12 HH16 MM11 MM25 PP02 PP15

Claims (14)

[Claims] 1. A photosensitive member, an intermediate transfer member on which a toner image on the photosensitive member is primarily transferred, and toner images of respective colors are sequentially transferred on the intermediate transfer member to superimpose the primary transfer images. A plurality of primary transfer means arranged corresponding to the respective photoconductors, a secondary transfer means for secondarily transferring the primary transfer image on the intermediate transfer body to a transfer material, and a transfer on the photoconductor In an image forming apparatus having a cleaning unit for cleaning the residual toner on the photoconductor, the cleaning unit holds the magnetic powder by a metal roller rotatably supported by a fixed shaft containing a magnet, and removes the magnetic powder. An image forming apparatus characterized in that a toner adhered thereto is cleaned by bringing it into contact with a photoconductor, and a lubricant is arranged so as to come into contact with the magnetic powder. 2. The image forming apparatus according to claim 1, wherein the toner of the toner image forms a two-component developer together with a carrier and is used. 3. The image forming apparatus according to claim 1, wherein the cleaning unit applies a bias to the metal roller to electrically attract the metal roller. 4. The image forming apparatus according to claim 1, wherein the lubricant is a solid lubricant. 5. The image forming apparatus according to claim 1, wherein the lubricant is a powder lubricant. 6. The image forming apparatus according to claim 1, wherein the toner of the toner image has a number average particle diameter of 3 to 8 μm. 7. The image forming apparatus according to claim 1, wherein the photoconductor has a drum shape. 8. The secondary transfer means to the transfer material comprises an intermediate transfer body as an image carrier, a backup roller and a secondary transfer roller sandwiching the intermediate transfer body, and the resistance value of the backup roller is 1 ×. 10 ⁵ to 1 × 10 ⁷ Ω,
The resistance value of the secondary transfer roller is 1 × 10 ⁵ to 1 × 10 ⁷ Ω, and constant current control is performed.
The image forming apparatus according to claim 1. 9. The toner has a shape coefficient variation coefficient of 16
% Or less, and the number variation coefficient in the number particle size distribution is 2
The image forming apparatus according to claim 1, wherein the image forming apparatus is 7% or less. 10. The relative position of the primary transfer means from the photoconductor to the intermediate transfer member is 10 m in the rotational direction upstream and downstream from the center point of the contact area between the photoconductor and the intermediate transfer member.
It is within m, 1 in any one of Claims 1-9 characterized by the above-mentioned.
The image forming apparatus according to item. 11. The position of the primary transfer roller as the primary transfer means is located downstream of the contact start point of the intermediate transfer body and the photoconductor in the traveling direction of the intermediate transfer body. The image forming apparatus according to any one of items. 12. The relative position of a secondary transfer roller as a secondary transfer means when the primary transfer image on the intermediate transfer body is secondarily transferred to the transfer material is the intermediate transfer body and the backup roller. The image forming apparatus according to any one of claims 1 to 11, wherein the contact area is within 20 mm on the upstream side and the downstream side in the rotation direction with respect to the center point of the contact area. 13. The image forming apparatus according to claim 1, wherein the plurality of photoconductors have respective developing means corresponding thereto. 14. The intermediate transfer member has a volume resistivity of 1 × 1.
The image forming apparatus according to claim 1, wherein the image forming apparatus is a semiconductive resin having a resistance of 0 ⁴ to 1 × 10 ¹² Ω · cm.