JP2000137382A - Toner seal member, developing device image forming device, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an end part fogging and to stably obtain a high-quality image while miniaturizing the device and surely preventing toner from being leaked by constituting an end-part leakage preventing member of a foaming polyurethane whose density and number of cells are specified. SOLUTION: End-part seal members 17 are made to abut on both end parts of a developing roller 10 so that the toner is not leaked from a gap between both end parts of the roller 10 and a developing blade 11 in the longitudinal direction. Thus, since the seal members 17 and the roller 10 are stuck to each other without leaving the gap, the toner is prevented from being leaked. The seal members 17 are made to adhere to the inside wall of a developing frame so as to abut on both ends the roller 10 by surrounding them. Besides the end- part leakage prevention members 15 are arranged in order to prevent the toner from being leaked from the gap between the blade 11 and the inside wall of the developing frame. The leakage prevention member 15 is formed by using the foaming polyurethane, whose density is 20 to 40 (kg/m3) and whose number of cells is 40 to 60 (pieces/25 mm), and stuck to the blade 11, the surface of the roller 10 and the inside wall of the developing frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner seal member for preventing toner leakage, a developing device using the same, an image forming apparatus, and a process cartridge.

[0002]

2. Description of the Related Art At present, most of image forming apparatuses such as copying machines and printers use an electrophotographic system, but this is achieved by selectively exposing an image carrier having a photosensitive layer formed thereon to a latent image. An image is formed, and the latent image is developed with toner by a developing device. This developing device, as shown in FIG.
The developing roller 50 as a toner carrier is rotated to form a toner layer having a small particle size on the surface of the roller, and the toner is supplied to the developing area of the image carrier 51 for development. A developing blade 52 as a toner layer regulating member is in contact with the developing roller 50 to regulate the toner layer thickness and to apply triboelectric charge to the toner.

In the above-mentioned developing device, if toner leaks from the developing device, the leaked toner adheres to unnecessary portions, which is not preferable. Therefore, it is necessary to prevent the toner from leaking out of the image forming apparatus. Here, the toner used is generally 10 μm in average particle size.
Since it is a very small powder of less than m, even small gaps need to be sealed.

For example, a developing device is sealed as shown in FIGS. FIG. 11 shows the developing roller 50.
FIG. 12 (a) is a sectional view taken along line AA of FIG. 11, and FIG.
FIG. 13B is a cross-sectional view taken along the line BB of FIG. 11, and FIG.
It is explanatory drawing seen from arrow F direction.

That is, as shown in FIG.
At both ends of the developing roller 50, an end seal member 54 made of an elastic material such as foamed polyurethane (malt plain) or felt is provided so as not to cause toner leakage from a gap between both ends in the longitudinal direction of the developing blade 52 and the developing blade 52. Abut. As a result, as shown in FIG. 12A, the end seal member 54 and the developing roller 50 can be in close contact with each other without a gap, so that the toner coated on the developing roller 50 can be prevented from leaking out of the developing device.

[0006] Further, as shown in FIG.
There is not a small gap between the inner wall 53 and the inner wall 53 of the developing frame. This is because if the end of the developing blade 52 interferes with the inner wall 53 of the developing frame, the toner coat at the end of the developing roller becomes unstable, the coat at the end becomes unstable, and an image defect occurs corresponding to the portion. It is because. Therefore, in order to avoid this and stably produce, the gap between the developing blade 52 and the inner wall 53 of the developing frame must be allowed to be not small. Therefore, in order to prevent the leakage of the toner from the gap, a new toner seal member (hereinafter, referred to as a toner seal member) is used.
This is referred to as an “end leak prevention member” 55).

The end leakage preventing member 55 is made of an elastic material such as polyurethane foam (malt plain).
As shown in FIG. 13 (b) and FIG. 13, the developing blade 52, the developing roller 50, and the inner wall 53 of the developing frame are arranged in close contact. This makes it possible to reliably prevent toner from leaking from the developing device.

[0008]

In recent years, as OA equipment has spread not only in offices but also in homes, it has been desired to reduce the size of not only the personal computer itself but also peripheral equipment such as printers.

However, if the longitudinal dimension of the developing device is reduced as much as possible in order to reduce the size of the developing device such as a printer in the electrophotographic system, both ends outside the developing area which have not been used conventionally, that is, recording of the transfer material, Since the portions outside the region (that is, both ends of the transfer material) are also used, there has been a problem that fog occurs at both ends of the transfer material.

The mechanism of the problem that fogging occurs at both ends of the transfer material will be described with reference to FIG.

FIG. 14 shows the distribution of the contact pressure of the developing blade in the longitudinal direction of the developing roller. The longitudinal position of the developing roller is
The left end of the developing blade 52 in FIG. 11 is set as a reference (0 mm).

The method of measuring the contact pressure is as shown in FIG.
An SUS thin plate 56 (50 μm thick) is sandwiched in the contact area between the developing blade 52 and the developing roller 50, and the force of pulling out one sandwiched sheet is measured with a spring scale, and the read value is measured. Expressed as contact pressure.

In order to prevent the leakage of the toner, the end leakage preventing member 55 needs to hold down the developing blade 52. Therefore, as shown in FIG. 14, the toner held at both ends of the developing roller is regulated by the developing blade 52 at a higher pressure than the other parts. Therefore, the end leakage prevention member
Since sufficient toner is not coated on the surface layer of the developing roller 50 at the position corresponding to 55, this portion cannot be allowed to enter the recording area. Therefore, making this portion adjacent to the recording area is the limit of miniaturization.

At this time, the end leakage prevention member 55 corresponds to the non-recording area of the transfer material, but the toner on the developing roller 50 corresponding to the position of the end leakage prevention member 55 is smaller than the other parts. It is regulated by a high contact pressure, so it has a higher tribo (charge per unit mass).

Therefore, since the toner at both ends has higher developability than the toner on the developing roller corresponding to the recording area of the transfer material, the toner fog becomes regular fog especially in a low humidity environment (RH 30% or less), and both ends of the transfer material This will make the part dirty (hereinafter referred to as "edge fog").

If the contact pressure of the end leakage preventing member 55 is simply reduced as a countermeasure against the end fogging, the toner leaks from the gap between the developing blade 52 and the inner wall 53 of the developing frame. You will not be able to fulfill your purpose.

Further, if the end leakage preventing member 55 is provided farther to the outside where the transfer material does not overlap, naturally the end fog does not occur, but this is contrary to the miniaturization of the apparatus. I will.

Further, in order to realize high image quality, the particle size of the toner has been reduced. However, when the size of the toner is reduced, the above-described fog is more likely to occur, and the toner is also more likely to leak.

Therefore, when a toner having a small particle size is used, it becomes more difficult to achieve both end fog and toner leakage prevention.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to reduce the fog at the end while stably preventing toner leakage while realizing the miniaturization of the apparatus. It is intended to provide a toner seal configuration for providing a high quality image.

[0021]

In order to achieve the above object, a typical configuration according to the present invention is to provide a toner carrying device for supplying toner to a developing area where a latent image is developed. A toner layer thickness regulating member that regulates the toner layer thickness on the body surface abuts on a surface opposite to the toner carrier abutting side, and the toner from between the inner wall of the developing frame and the toner layer thickness regulating member. the toner seal member for sealing the leak, density 20~40 (kg / m ^3), the number of cells 40 to 60 (number / 25 m
m) It is characterized by comprising foamed polyurethane.

In the above configuration, the density of the foamed polyurethane used as the toner seal member is 20 to 40 (kg / m ³ ).
Soft and the number of cells is 40-60 (pcs / 25mm
) And a material having a high toner sealing property, it is possible to perform sufficient toner sealing without strongly pressing the toner layer thickness regulating member.

For this reason, even in a low-temperature and low-humidity environment, edge fogging can be prevented, and the toner on the toner carrier, which tends to pass through the gap in the inner wall of the developing frame, can be scraped to prevent the leakage of the toner. . Accordingly, by configuring the developing device in which the toner seal member is used to seal the toner, the width of the developing device in the longitudinal direction can be suppressed as short as possible. Miniaturization can be achieved.

[0024]

Next, an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall schematic explanatory view of an electrophotographic image forming apparatus provided with a developing device sealed by a toner seal member, and FIGS. 2 to 4 are explanatory diagrams of a seal configuration of the developing device. FIGS. 5 to 8 show the results of a comparative experiment when sealing is performed using the end leakage prevention member as the toner seal member according to the present embodiment and a conventional end leakage prevention member.

{Overall Configuration of Image Forming Apparatus} First, the overall configuration of an electrophotographic image forming apparatus will be described with reference to FIG. The image forming apparatus A is roughly classified into an electrophotographic process, and includes a charging device, an image carrier, an exposure device, a developing device, a transfer device, a cleaning device, and a fixing device.

Of these, the process cartridge is one in which the charging device, the image carrier, the developing device, and the cleaning device are integrally compactly integrated.

The charging roller 1 serving as a charging device has a sponge layer provided on a metal shaft, and further covered with a resin layer. By pressing both ends of the metal shaft, the charging roller 1 is brought into contact with a photosensitive drum 2 as an image carrier, and is driven to rotate with respect to the photosensitive drum 2 in the direction of arrow a. A charging bias power supply (not shown) for applying a DC voltage and an AC voltage is connected to the charging roller 1. Thereby, the surface of the photosensitive drum 2 can be charged to a predetermined potential.

The photosensitive drum 2 rotates in the direction of arrow b in the figure, and its surface is charged by the charging roller 1. Then, the exposure device 7 irradiates the photosensitive drum 2 with laser light based on image information. A latent image is formed. The resolution of the image is determined by the exposure device 7.

The developing device 3 includes a toner 8 for visualizing an electrostatic latent image on the photosensitive drum 2, a developing container 9 containing the toner 8, and a developing roller 10 as a toner carrier for carrying the toner 8. The developing blade 11 is a toner layer thickness regulating member for regulating the thickness of the toner layer on the developing roller 10 and applying a predetermined charge.

The developing roller 10 is provided with a predetermined gap from the photosensitive drum 2, rotates in the direction of arrow c in the figure, and applies a bias obtained by superimposing an AC voltage on a DC voltage from a developing bias power supply (not shown). The electrostatic latent image formed on the drum 2 is visualized.

The transfer roller 5 has a sponge layer provided on a metal shaft. The transfer roller 5 is connected to a transfer bias power supply (not shown), and is provided so as to be in contact with the photosensitive drum 2 and to be driven to rotate in the direction of arrow d. This allows
The visible image on the photosensitive drum 2 formed as described above is transferred to the transfer material P.

After the transfer step, the toner 8 that has not been completely transferred remains on the photosensitive drum 2. The remaining toner 8 is scraped off from the photosensitive drum 2 by a cleaning blade 12 provided in the cleaning device 4 and collected in a cleaning container 13.

The fixing device 6 can pressurize and heat the unfixed image formed on the transfer material P to melt the toner 8 on the transfer material P, so that it can be semi-permanently stored on the transfer material P. It forms an output image.

{Developing Apparatus} As described above, the developing apparatus 3 develops the electrostatic latent image formed on the photosensitive drum 2 with toner and visualizes the electrostatic latent image. A developing roller is rotatably attached to an opening of a developing container 9 and a developing blade 11 is attached to the developing roller 10 to form a toner layer on the surface thereof and to supply a toner to a developing area where the latent image is developed. Are mounted so as to be pressed against each other.

In the present embodiment, the toner 8 used for the development
Is a negatively chargeable one-component dry toner in which 100 parts by weight of magnetite is kneaded with styrene-acrylic resin, and the average particle diameter is reduced to about 7 μm by grinding.

The developing roller 10 is obtained by roughening a 16 mm-diameter aluminum tube by sandblasting, and coating the surface of the surface with a coating of phenolic resin mixed with conductive fine particles of carbon and graphite.

In order to control the toner to a desired charge amount and obtain a stable image quality, a compounding ratio of carbon + graphite: phenol = 1: 1 to 1: 3 is preferable. The blast area and the coat area substantially coincide with each other, and include at least the entire area where the developing blade 11 contacts. Therefore, both ends of the developing roller 10 are in a state where the aluminum background is exposed.

In the present embodiment, the length of the blast and coat areas in the longitudinal direction is 212 mm. In the developing roller 10, Ra of the surface portion of the developing roller corresponding to the print guarantee area was set to about 1.2 μm. The surface roughness is Ra
(Center line average roughness: based on JISB601-1982), but other definitions (ten point average roughness Rz (such as based on JISB601-1982)) may be used.

As the toner layer thickness regulating member, a developing blade 11 made of urethane rubber having a thickness of 1.0 mm and a length of 210 mm is used. The developing blade 11 is adhered to one surface of the supporting metal plate 16 and is in contact with the developing roller 10 so as to cover the above-described blast and coat area of the developing roller 10 over the entire area in the longitudinal direction. The length of the developing blade 11 needs to be equal to or larger than the maximum width that the image forming apparatus guarantees printing.

In this embodiment, since the maximum sheet passing width is an image forming apparatus of A4 size, the length of the developing blade 11 is set to 210 mm corresponding to this, as described above. The contact pressure of the developing blade 11 against the developing roller 10 is about 20 gf / cm at the center in the longitudinal direction.

The developing roller 10 and the developing blade
Seal members are attached to both ends in the longitudinal direction of 11 to seal so that toner does not leak from the ends.

{Seal Configuration} To prevent toner from leaking from the gap between the longitudinal ends of the developing roller 10 and the developing blade 11, end sealing members 17 are provided at both ends of the developing roller 10.
Abut. As a result, the end seal member 17 and the developing roller 10 are brought into close contact with each other without any gap, thereby preventing toner leakage. In the present embodiment, the end seal member 17 is adhered to the inner wall 14 of the developing frame so as to surround and contact both ends of the developing roller 10 (50), as in FIG. The end seal member 17 is made of Teflon felt having a thickness of 2 mm.

As described with reference to FIG. 13, the gap between the developing blade and the inner wall of the developing frame is inevitably allowed, so that the leakage of the toner from the gap is prevented. In the end leakage prevention member 15 (55)
Is provided.

The feature of the present embodiment is that the amount of pressure applied to the end leakage preventing member 15, which presses the developing blade 11 at both ends of the developing roller 10, is reduced. In particular,
By changing the material of the end leakage preventing member 15 to a soft material, the developing blade contact pressure at both ends of the developing roller is reduced while the sealing property of the toner at both ends of the developing blade is secured.

In this embodiment, foamed polyurethane (5 mm in width and 5 mm in thickness) having a density of 30 kg / m ³ and a number of cells of 50/25 mm is used as the end leakage preventing member 15.
As shown in (b), the developing blade 11 (52) and the developing roller 1
0 (50) surface and the inner wall 14 of the developing frame (not shown). As a result, leakage of toner from the gap between the developing blade 11 and the inner wall 14 of the developing frame can be prevented.

FIG. 3 shows the state when the developing blade 11 is removed in FIG. 1 when viewed from the direction F in FIG. In FIG. 3, before the developing roller 10 is assembled, the end leakage preventing member 15 is installed at a position I which protrudes by H (0.1 mm in this embodiment) from a contact position G with the developing roller 10. However, when the developing roller 10 is assembled there, only H is crushed.

Then, as shown in FIG. 4A, when the developing blade 11 and the developing roller 10 are actually assembled, the portion of the end leakage preventing member 15 which does not contact the developing blade 11 is
Although it is crushed by the same amount as the end leakage prevention member 15 of FIG. 3, the portion of the end leakage prevention member 15 that contacts the developing blade 11 is further crushed by the thickness of the developing blade (1.0 mm in this embodiment).

The portion where the end leakage preventing member 15 is sandwiched between the developing roller 10, the developing blade 11, and the inner wall 14 of the developing frame is brought into contact with the developing roller 10 (H> 0), so that This has the effect of stripping off the toner and eliminating the toner that passes through the gap between the end seal member 17 and the developing blade 11 and leaks out of the developing device, thereby preventing end leakage.

<Experimental Results> Next, the results of verifying the effect of the present invention by applying the above-described developing device including the end leakage preventing member 15 having the above structure to an image forming apparatus will be described. The experimental results will be described with reference to FIGS.

FIG. 6 shows the relationship between the longitudinal position of the developing roller 10 and the fog after sampling a white image on the entire surface in a low temperature and low humidity environment of 10 ° C. and 10% RH.
The measurement of fog was performed with a densitometer TC-6DS manufactured by Tokyo Denshoku Co., Ltd. The fog R (%) is expressed as follows: R1 (%) is the measured value of the entire white image passed through the image forming apparatus, and R2 (%) is the measured value of the paper not passed through the image forming apparatus. R1
-R2 is defined. The larger the R, the worse the fog.

FIG. 7 shows the relationship between the longitudinal position of the developing roller 10 and the tribo held by the toner coated on the developing roller 10 in this embodiment. The position in the longitudinal direction of the developing roller 10 is represented with the left end of the developing blade in FIG. 2 as a reference (0 mm). The tribo is obtained by sucking the toner on the developing roller 10, measuring the amount of charge with an electrometer manufactured by Kesley, and dividing the amount of charge by the weight.

As a comparative example, in addition to the foamed polyurethane of the end leakage prevention member 15 employed in the present embodiment, the following polyurethane foams of the end leakage prevention member including the conventional example (1 to 6)

1. Density 60kg / m ³ , Number of cells 60 / 25mm (conventional example)

2. Density 40 kg / m ^3, the cell number 60 strokes / 25mm

3. Density 30kg / m ³ , Number of cells 50 / 25mm (this embodiment)

4. Density 30kg / m ³ , Number of cells 30 / 25mm

5. Density 20kg / m ³ , Number of cells 40 / 25mm

6. Density 20kg / m ³ , Number of cells 30 / 25mm

The case where the six types are used is also added. Other configurations are the same as those of the above-described embodiment.

The bias condition of the image forming apparatus is such that a DC component of -450 V superimposed with a rectangular wave of 1.6 KVpp / 1.5 kHz is used as a developing bias, and the dark part potential VD is -700 V and the light part potential is -200 V.

The process speed was set to 60 mm / sec.
It is assumed that eight sheets of four size paper can be output in one minute in the vertical direction.

As shown in FIG. 6, the result of the experiment is that the fog at both ends of the image is as high as about 3% in the conventional example using one member, whereas the members 2 to 6 including the present embodiment are fogged. When the is used as the end leak prevention member 15, both the end and the center are less than 2.5% (if the fog is less than 2.5%, it cannot be perceived as an end fog).
A good image with little fog could be obtained.

Further, as shown in FIG. 7, the triboelectric member corresponding to the position of the end leakage preventing member has a contact pressure of -12 μC / g or less, although it is higher than the center of the image area, and one member has It could be smaller than the tribo corresponding to the position of the end leakage preventing member of the conventional example used, and was uniform over substantially the entire area of the developing roller 10 in the longitudinal direction.

Further, the distribution of the contact pressure between the developing roller 10 and the developing blade 11 in the longitudinal direction is as shown in FIG. 5 when the left end of the developing blade 11 in FIG.

As described above, in order to prevent the toner from leaking, the end leakage preventing member 15 needs to hold down the developing blade 11, so that as shown in FIG. The toner held in the portion is regulated by the developing blade 11 at a higher pressure than in other portions.

However, 2, 3, including this embodiment,
When the end-preventing members of the foamed polyurethane of Nos. 4, 5 and 6 are used, the contact pressure at both ends of the developing blade 11 is larger at the central portion in the longitudinal direction of the developing blade 11 as compared with one member (conventional example). There is no difference, and it is almost uniform. And
At both ends, the height is still higher than the central portion in the longitudinal direction of the developing blade 11, but is clearly lower than that of one member (conventional example).

This is because the pressing force for pressurizing the both ends of the developing blade 11 is lower than that of the conventional example using the member 1 because the end leak preventing members 2 to 6 are lower at both ends of the developing blade 11. It is considered that the contact pressure decreased, and the tribo at both ends decreased compared to the conventional example using one member.

Next, the leakage of the toner at the end when the members 1 to 6 are used as the end overflow preventing member 15 will be described. FIG.
Is the result. From this, it was found that when the members 4 and 6 were used as the end leakage prevention member 16, end toner leakage occurred.

Members 2 to 6 as end leakage prevention member 15
Is softer than the member 1 of the conventional example, and the density (kg / m ³ ) and the number of cells (cells / 25 mm)
Is considered to be softer in order from member 1 toward 6.

However, both members 3 and 4 have a density of 30 (kg).
/ m ³ ), and is considered to affect end toner leakage when the members 3 and 4 are used.
Although the abutment pressures at both ends of both are almost 23 to 24 (gf / cm 2), the results of edge fog are actually good, but the results of toner leakage at the ends are different. When the member 3 is used, the result of the end toner leakage is good. However, when the member 4 is used, the end toner leak occurs, and the toner leaks outside the developing device and stains the inside of the image forming apparatus and the transfer material. Oops. The same applies to members 5 and 6. The difference between the two types of the members 3 and 4 and between the members 5 and 6 was the number of cells per unit length of the polyurethane foam as the end leakage preventing member.

FIG. 4A shows the positional relationship between the end leakage preventing member 15, the developing blade 11, and the developing roller 10. FIGS. 4 (b) and 4 (c) are enlarged views of the end leakage preventing member 15 abutting on the developing roller 10 of FIG. 4 (a). FIG. 4 (b) is the member 3 and FIG. This corresponds to the member 4.

The members 3 and 4 have the same density, but have different numbers of cells. The number of the member 3 is 50 (pieces / 25 mm), and the number of the member 4 is 30 (pieces / 25 mm).

That is, since the members 3 and 4 have the same density, as shown in FIGS. 4 (b) and 4 (c), each member 3 is small in the foamed polyurethane foam, The wall that separates the foam is thick, and the wall that separates the foam is thick.

The end toner leakage occurs when the toner enters the gap at the end of the developing roller 10 that does not contact the developing blade 11 and leaks out of the developing device.
Therefore, the foamed polyurethane is brought into contact with the end of the developing roller 10 which does not come into contact with the developing blade 11, so that the toner on the surface of the developing roller 10 which is going to enter the gap is scraped off by the end leak preventing member 15, so that the end is prevented. It is considered that no toner leakage occurs.

At this time, the end leakage preventing member 15 pushes the developing roller 10 with a certain pressing pressure that does not cause end fog as described above, but faces the gap between the developing blade 11 and the inner wall 14 of the developing frame. The toner on the surface of the developing roller 10 cannot be scraped off only by being pressed at the above-mentioned predetermined pressure applied from the end leak prevention member 15.

This is because, even when pressed with a pressure equal to or higher than a certain value, as shown in FIG. 4 (b), as compared with the member 3 having a large number of cells, as shown in FIG. In the case of the member 4 having a small number, it is considered that the toner is less likely to come into contact with the toner on the surface of the developing roller, and since each of the foamed diameters is large, the toner easily passes therethrough, thereby causing end toner leakage. Even if the density of the foamed polyurethane is not less than a certain value, if the number of cells per unit length of the foamed polyurethane is not not less than a certain value, it means that end toner leakage occurs.

Thus, the end toner leakage can be prevented by the end leakage prevention member.
In order to prevent the problem with 15, it is necessary not only to press the developing roller 10 and the developing blade 11 with a certain pressure or more, but also to capture and scrape off the toner with a foam material having a certain number of cells or more. It turns out.

That is, if the members have approximately the same density,
Foam (cell) Even if each wall is thin, its number (cell number)
Is more effective.Also, even with the end leak preventing member 15 that can apply sufficient pressure to prevent end fog, if the foam diameter is large, the remaining toner leak preventing effect may be reduced. I understand.

Since the members 5 and 6 have the same relationship, it is considered that what has been described above is correct.

For this reason, the end leak preventing member 15 has a density of 20 to 40 (kg / m ³ ) and a cell number of 40 to 60 (cells / 25 m
m) by using the foamed polyurethane, while maintaining the effect of scraping off the toner on the developing roller 10 that is going to pass through the gap between the developing roller 10 and the inner wall 14 of the developing frame and preventing the end toner from leaking, Further, it is possible to reduce end fog in a low-temperature and low-humidity environment, which has been generated corresponding to the end leak prevention member, and also to realize a downsized developing device at the same time.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the end leakage prevention member 15 described in the first embodiment is incorporated in the process cartridge B to constitute a process cartridge that can be attached to and detached from the image forming apparatus main body. It is in. In the process cartridge B shown in FIG. 9, the charging device 1, the photosensitive drum 2, the developing device 3, and the cleaning device 4 described in the first embodiment are integrated to constitute a process cartridge B.

The process cartridge B is detachably mountable to the mounting section 18 of the image forming apparatus. By mounting the process cartridge B on the mounting section 18, a drive transmitting section for driving the photosensitive drum 2 and the like, a power supply, and the like are provided. The toner image can be formed on the photosensitive drum 2 by being connected to an image forming apparatus main body having a high voltage circuit for supplying a bias for forming an image.

The toner image formed on the photosensitive drum 2 is transferred to a transfer roller 5 provided in the main body of the image forming apparatus.
Is transferred onto the transfer material P, and is fixed by the fixing device 6.

The photosensitive drum 2 is not transferred to the transfer material P.
The transfer residual toner remaining on the toner is removed by the cleaning blade 12 in the cleaning device 4 in the process cartridge B.

At this time, the developing blade 11
Of the toner rubbed with, the toner at the longitudinal end of the developing roller 11 has a slightly higher triboelectricity than the toner at the center in the longitudinal direction due to the end leakage prevention member 15, but the toner on the transfer material Since the tribo is not high enough to be developed in a white background area on the photosensitive drum 2 outside the printing area,
As a result, no edge fogging occurs.

Further, the developing roller 10 which tries to leak to the outside of the developing device through the gap between the developing roller 10 and the inner wall 14 of the developing frame.
The toner present at the upper end is reliably scraped off from the developing roller 10 by the end leak preventing member 15, and as a result, the end toner does not leak.

Therefore, by forming the process cartridge B in which the developing device 3 whose end is sealed by the above-mentioned end leakage preventing member 15 is incorporated, the developing device which passes through the gap between the developing roller 10 and the inner wall 14 of the developing frame is developed. While maintaining the effect of scraping off the toner on the roller 10 to prevent the leakage of the toner, it is necessary to reduce the edge fog in a low-temperature and low-humidity environment that has conventionally occurred corresponding to the edge leakage prevention member. The size of the developing device and the process cartridge can be reduced at the same time.

[Other Embodiments] The process cartridge in the present invention may be any as long as it has a photosensitive drum as an electrophotographic photosensitive member and at least a developing device as process means acting on the photosensitive drum. Therefore, as an aspect of the process cartridge, other than the one in which the photosensitive drum, the developing device, the charging device, and the cleaning device are integrally formed into a cartridge as in the above-described embodiment, and the cartridge is detachable from the apparatus main body, for example, A photoreceptor drum, a developing device, and a charging device are integrally formed into a cartridge so that the photoreceptor drum can be attached to and detached from an apparatus main body. A photoreceptor drum, a developing device, and a cleaning device are integrally formed into a cartridge so that the photoreceptor drum can be attached to and detached from the apparatus main body. There is a type in which the photosensitive drum and the developing device are integrally formed into a cartridge, which is detachable from the apparatus main body. The process cartridge can be attached to and detached from the apparatus main body by the user, and as a result, the maintenance of the apparatus main body can be performed by the user himself.

The image forming apparatus according to the present invention may take the form of a copying machine, a facsimile machine, or the like in addition to the printer described above.

[0092]

According to the present invention, since the present invention is configured as described above,
Since the density of the foamed polyurethane used as an end leakage prevention member as a toner seal member is 20 to 40 (kg / m ³ ), it is soft and the number of cells is 40 to 60 (cells / 25 mm), and the toner sealability is high. Because of the material, sufficient toner sealing can be performed without strongly pressing the toner layer thickness regulating member.

Therefore, the end fog can be prevented even in a low-temperature and low-humidity environment, and the toner on the toner carrier, which tends to pass through the gap in the inner wall of the developing frame, can be scraped to prevent the leakage of the toner. . Accordingly, by configuring the developing device in which the toner seal member is used to seal the toner, the width of the developing device in the longitudinal direction can be suppressed as short as possible. Miniaturization can be achieved.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of an electrophotographic image forming apparatus including a developing device sealed by a toner seal member.

FIG. 2 is a schematic explanatory view of a seal configuration in a developing roller longitudinal direction.

FIG. 3 is an explanatory diagram of a seal configuration of a longitudinal end portion leakage prevention member and the like of a developing roller.

4 (a) is an explanatory view of a state sealed by an end leak preventing member, (b) is an explanatory view of an end leak preventing member having a large number of cells, and (c) is an end leak preventing member having a small number of cells. FIG.

FIG. 5 is an explanatory diagram of a contact pressure distribution in a longitudinal direction of a developing blade.

FIG. 6 is an explanatory diagram of distribution of fog on a transfer material in a longitudinal direction of a developing blade.

FIG. 7 is an explanatory diagram of a distribution of tribo on a developing roller in a longitudinal direction of a developing blade.

FIG. 8 is an explanatory diagram showing a result of an operation of each material of the end leak prevention member.

FIG. 9 is an explanatory diagram of a process cartridge having a developing device sealed by an end leakage prevention member.

FIG. 10 is an explanatory diagram of a developing configuration.

11 is an explanatory diagram of one end side of the developing roller and the developing blade as viewed from the direction of arrow E in FIG. 10;

FIG. 12A is a schematic cross-sectional explanatory view of an end seal member,
(b) is a schematic sectional explanatory view of the end leakage prevention member.

13 is an explanatory diagram of a portion where the developing roller, the developing blade, and the inner wall of the developing frame are in contact, as viewed from the direction of arrow F in FIG. 10;

FIG. 14 is an explanatory diagram of a contact pressure distribution in a longitudinal direction of a developing blade according to a conventional example.

FIG. 15 is an explanatory diagram of a drawing pressure measuring method.

[Explanation of symbols]

 A: Image forming apparatus B: Process cartridge P: Transfer material 1: Charging roller 2: Photoconductor drum 3: Developing device 4: Cleaning device 5: Transfer roller 6: Fixing device 7: Exposure device 8: Toner 9: Developing container 10 … Developing roller 11… Developing blade 12… Cleaning blade 13… Cleaning container 14… Development frame inner wall 15… End leakage prevention member 16… Support metal plate 17… End seal member 18… Mounting part

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Akira Domon 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Shinya Noda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Nishijo Toko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Satoru Motohashi 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H071 BA03 BA13 BA27 BA35 DA08 2H077 AD06 AD13 AD17 AD36 BA08 BA09 CA12 FA01 FA03 FA22

Claims (4)

[Claims] 1. A toner layer supporting member for contacting a toner carrier for supplying toner to a developing area for developing a latent image to regulate a toner layer thickness on a surface of the toner carrier. A toner sealing member that abuts on the surface opposite to the abutting side and seals toner leakage from between the inner wall of the developing frame and the toner layer thickness regulating member, has a density of 20 to 40 (kg / m ³ ); Number of cells is 40-60 (pcs / 25mm)
A toner seal member comprising a foamed polyurethane. 2. A developing device for developing a latent image with toner, a toner carrier for supplying toner to a developing area for developing the latent image, and a toner on the surface of the toner carrier in contact with the toner carrier. A toner layer thickness regulating member that regulates the layer thickness, and abuts on a surface of the toner layer thickness regulating member opposite to the toner carrier abutting side, and the inner wall of the developing frame and the toner layer thickness regulating member. As a toner sealing member for sealing toner leakage from between, the density is 20 to 40 (kg / m ³ ) and the number of cells is 40 to 60 (cells / 2).
(5 mm) A developing device using a toner seal member made of polyurethane foam. 3. An image forming apparatus for forming an image by developing a latent image formed on an image carrier with a toner, comprising: an image carrier; and a developing device for developing the latent image formed on the image carrier with toner. An image forming apparatus comprising: the developing device according to claim 2 as the developing device. 4. A developing device according to claim 2, further comprising: an image carrier, and at least a developing device as a process unit acting on the image carrier. A process cartridge comprising: