JPH0736278A - Developing device - Google Patents

Abstract

PURPOSE:To provide a developing device by which the thin layer of an excellently and positively electrified toner is formed on a developing sleeve while an elastic blade made of silicone rubber is allowed to satisfy all of electrification characteristic to the positively electrified toner releasing property from the toner and abrasion resistance by specifying the kind and the quantity of silica to be added to the silicone rubber as a reinforcing agent. CONSTITUTION:The elastic blade 14 is constituted by integrating a silicone rubber elastic layer 14a abutting on the developing sleeve 3 and a backing supporting layer 14b made of an SUS sheet; and dry silica is added in the ratio of 8-30 pts.wt. per 100 pts.wt. polysiloxane polymer being rubber material in the silicone rubber. Since the dry silica stronger in negative electrification property is added to the polysiloxane polymer strong in negative electrification property, the electrification polarity of the blade 14 is raised, and the positively electrified toner 6 on the sleeve 3 is excellently electrified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a latent image carrier formed on an electrophotographic photoreceptor or an electrostatic recording dielectric in an image forming apparatus such as a copying machine, an image recording apparatus, a printer or a facsimile. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for developing and visualizing an image, and more particularly to a developing device in contact with a developer carrier to regulate the amount of one-component developer and the amount of charge on the developer carrier.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, an image recording apparatus, a printer, a facsimile, etc., a latent image formed on a latent image carrier made of an electrophotographic photoreceptor or an electrostatic recording dielectric is It is developed by a developing device and visualized as a toner image.

As one of such developing devices, various dry one-component developing devices have been proposed and put into practical use. However, in any of the developing devices, it is extremely difficult to form a thin layer of toner, which is a one-component developer, on the developer carrying member.

However, at the present time when improvements in image sharpness, resolution, etc. are required, development of a toner thin layer forming method and its apparatus is indispensable, and in response to this, some measures have been proposed. ing.

For example, as shown in Japanese Patent Laid-Open No. 54-43038, an elastic blade made of rubber or metal is brought into contact with a developing sleeve which is a developer carrying member, and the elastic blade and the developing sleeve are brought into contact with each other. There is a method in which a thin layer of toner is formed on a developing sleeve by allowing toner to pass through between portions to be regulated, and sufficient triboelectric charge is imparted to the toner by friction at the contact portion.

In this case, when the non-magnetic toner is regulated by the elastic blade, a toner supply member for supplying the toner on the developing sleeve is required separately. this is,
In the case of magnetic toner, the magnetic force of the magnet in the developing sleeve can supply the toner onto the developing sleeve.
This is because the non-magnetic toner cannot supply the toner by magnetic force.

Therefore, conventionally, a developing device as shown in FIG. 6 has been proposed. In this conventional developing device, the developing container 2 containing the non-magnetic toner 6 as a one-component developer is
An elastic roller 5 using a polyurethane home, a foam made of sponge, or a fur brush that abuts on the developing sleeve 3 at a position upstream of the elastic blade 4 in the rotational direction of the developing sleeve 3 is provided. The toner is supplied onto the developing sleeve 3 by rotating in the direction. After that, the toner 6 is sent to the contact portion between the elastic blade 4 and the developing sleeve 3 as the developing sleeve 3 rotates, and is thinned to be used for developing the electrostatic latent image on the photosensitive drum 1. Then, the toner 6 remaining on the developing sleeve 3 without being consumed for development is peeled off by the elastic roller 5, and new toner is supplied by the elastic roller 5,
The above operation is repeated.

By adopting such a constitution, a thin layer of the non-magnetic toner 6 can be satisfactorily formed on the developing sleeve 3, and the electrostatic latent image on the photosensitive drum 1 can be developed. , It became possible to faithfully reproduce a solid black image in a wide area and always obtain a stable image.

By the way, for the purpose of further improving the image quality and quick start of the copying operation, the toner has a small particle size,
When the melting point was lowered and the copying operation for several thousand sheets was repeated, the following problems occurred. (1) When an elastic blade made of metal such as stainless steel is used, the releasability of the toner is poor, and the toner sticks to the contact surface of the elastic blade with the developing sleeve, especially in a high humidity environment. The toner on the sleeve has coating unevenness and streaks, which appear on the image. (2) In order to solve the above problems and improve the chargeability of the positive polarity toner (positive polarity charging toner), when a fluororesin, fluororubber or the like is used for the elastic blade, the positive polarity charging toner is used because of its negative property. Can be satisfactorily charged, and the releasability is improved as compared with a metal blade, so that toner adhesion is also reduced. However, since the wear resistance of the elastic blade decreases,
As the copying operation progresses, the contact state of the elastic blade with the developing sleeve changes, and it becomes difficult to stabilize the regulation of the toner amount.

As described above, the elastic blade is required to have releasability for toner, abrasion resistance, and controllability of toner chargeability. However, some of these requirements are not satisfied, and therefore the above-mentioned problems occur. Has occurred.

[0011]

In order to solve the above-mentioned problems, it has been proposed to use an elastic blade made of silicone rubber for positive toner, in particular.

Silicone rubber not only exhibits releasability to toner as much as fluororesin and fluororubber, but also
Abrasion resistance can also be improved by adjusting the polymer crosslink density of the siloxane polymer as the raw material. Silicone rubber, like fluororubber, has a strong negative chargeability, and therefore can positively charge the positive polarity toner, and is suitable as an elastic blade for the positive polarity toner.

The above-mentioned silicone rubber is usually produced by adding a reinforcing agent such as silica and an expanding filler such as diatomaceous earth to a siloxane polymer as a raw material. This silicone rubber is used as an elastic blade for positive polarity toner. In order to be able to use it optimally, it is necessary to pay sufficient attention to the materials and amounts of these additives.

According to the experiments conducted by the present inventors, among the above additives, the factor that most affects the charging characteristics of the silicone rubber and the mechanical characteristics relating to the charging polarity of the toner used is that of silica used as a reinforcing agent. It is the material and amount, and these factors need to be specified within an appropriate range and type.

However, conventionally, since the relationship between the charging polarity of the toner used and the above factors has not been taken into consideration, the following inconvenience has occurred. That is, when wet silica having a high water content is added, the charge imparting ability of the obtained elastic blade in a high humidity environment is reduced, and the environmental stability is impaired. When dry silica with low water content or hydrophobically treated silica is used, if the addition amount is large, the charging ability of the elastic blade is improved, but on the other hand, since the hardness increases, the elastic blade comes into contact with the developing sleeve. I can't get enough width,
The uniformity of toner application on the developing sleeve is reduced, and the developed image becomes uneven. On the other hand, when the addition amount of silica having a low water content is small, not only the charging ability of the silicone rubber is lowered, but also the mechanical strength is lowered and problems such as chipping and abrasion of the rubber occur.

An object of the present invention is to specify the type and amount of silica to be added to silicone rubber as a reinforcing agent, so that an elastic blade made of silicone rubber can be charged with a positively chargeable toner, and the releasability from the toner can be improved. It is an object of the present invention to provide a developing device capable of forming a thin layer of a positively charged toner that is well charged on a developing sleeve while satisfying all of the abrasion resistance and using it for development.

[0017]

The above object can be achieved by the developing device according to the present invention. In summary, the present invention provides a non-magnetic one-component developer having a positive chargeability, which is carried on a developer carrying member and conveyed to a developing area facing the image carrying member, by an elastic force applied to the developer carrying member. In a developing device regulated by a regulation member to regulate the amount of the developer on the developer carrier and to triboelectrically charge the developer to a positive polarity, at least a portion of the elastic regulation member that is in contact with the developer carrier. Is a silicone rubber, and 8 to 30 parts by weight of dry silica per 100 parts by weight of the rubber raw material is added to the silicone rubber. It is also possible to add 5 to 30 parts by weight of hydrophobically treated silica instead of dry silica. Further, a magnetic one-component developer can be used in place of the non-magnetic one-component developer, and the dry silica is added in an amount of 5 to 40 parts by weight.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic structural view showing an embodiment of the developing device of the present invention. The developing device in FIG. 1 shows a state during a developing operation.

In FIG. 1, reference numeral 2 is a developing container containing a positively charging non-magnetic toner 6 as a one-component developer, and the developing container 2 is located at a position facing the photosensitive drum 1 in the longitudinal direction (paper surface) of the developing device. A developing sleeve 3 that rotates in the direction of arrow b is provided in the opening. The developing sleeve 3 has a right half peripheral surface protruding into the container 2 and a left half peripheral surface exposed from the outside of the container 2 as viewed in the drawing. The surface of the developing sleeve 3 exposed to the outside of the container 2 is arranged so as to correspond to the photosensitive drum, which is an image carrier rotating in the direction of arrow a, with a slight gap.

An elastic blade 14 is provided as an elastic regulating member at a position above the developing container 2 of the developing sleeve 3.
The elastic blade 14 is inclined in a direction in which it is lowered toward the upstream side in the rotation direction of the developing sleeve 3, and is in contact with the upper outer peripheral surface of the elastic blade 14 while being inclined in the rotation direction. The elastic blade 14 is formed in a two-layer structure composed of a silicone rubber on the side that abuts the developing sleeve 3 and a thin stainless steel plate as a backing support layer. As a result, the toner 6 carried on the developing sleeve 3 is rubbed against the abutting portion between the elastic blade 14 and the developing sleeve 3 to impart triboelectric charge to the toner, and at the same time, the toner that has entered between the abutting portions. 6
Is thinly applied on the developing sleeve 3 to form a thin layer of the toner 6.

The present invention is characterized by the structure of the elastic blade 14. The material and action of the elastic blade will be described later.

An elastic roller 5 as a developer supplying / separating means is provided at a position upstream of the elastic blade 14 in the rotation direction of the developing sleeve 3. The elastic roller 5
Is abutted on a portion of the developing sleeve 3 on the side opposite to the photosensitive drum 1, and is rotatably supported in the direction of arrow c (that is, the opposite direction at the abutting portion). By the rotation of the elastic roller 5, the toner 6 is carried and supplied to the vicinity of the developing sleeve, and the toner 6 is rubbed against the developing sleeve 3 at the contact portion between the developing sleeve 3 and the elastic roller 5, so that the developing sleeve 3 develops. The toner 6 is attached onto the surface 3.

Below the developing sleeve 3, a lower seal member 7 abuts against the developing sleeve 3 with a slight pressure, and is brought into contact with the developing sleeve 3. The undeveloped toner on the developing sleeve 3 is transferred to the container 2. The toner is allowed to pass through and the toner is prevented from being exposed from the inside of the container 2.
A toner sealing member 8 made of foam is provided between the lower seal member 7 and the bottom surface of the developing container 2, and the lower seal member 7 is provided.
The toner is prevented from entering between the bottom of the container 2 and the bottom of the container 2.

The photosensitive drum 1 is, for example, a so-called xerographic photoreceptor for forming an electrostatic latent image by the Carlson process, a photosensitive for forming an electrostatic latent image by a process described in Japanese Patent Publication No. 42-23910, which has an insulating layer on its surface. A body, an insulator that forms a latent image by an electrostatic recording method, and other members that form an electrostatic latent image (potential latent image) by an appropriate method are used.

The developing sleeve 3 is made of a material such as aluminum or stainless steel, but a conductive rubber roller may be used. The form is not limited to the cylindrical body (sleeve), and may be an endless belt. The developing sleeve 3 in this embodiment is formed with an appropriately roughened and roughened surface, which increases the chances of friction between the surface of the developing sleeve 3 and the toner, and improves the transportability of the toner 6. There is.

The roughened surface has a surface roughness Rz of 1 to 10.
It is obtained by subjecting the surface of the developing sleeve 3 to sandblasting with irregular-shaped alundum abrasive grains or sandblasting with regular-shaped glass beads so that the thickness becomes μm. Alternatively, a convex rough surface may be formed on the surface of the developing sleeve 3 by using conductive particles such as particles of metal oxide, graphite, and carbon, which can independently form the convex, and May be bound with a binder resin such as a phenol resin or a fluororesin, and a concave portion may be formed on the surface of the binder resin, whereby a roughened surface is obtained on the surface of the developing sleeve 3. In this embodiment, the developing sleeve 3
Is based on an aluminum sleeve with a diameter of 16 mm,
The surface of this was blasted with regular glass beads (# 600) to have a surface roughness Rz of about 3 μm.

The elastic roller 5 is made of polyurethane foam,
It consists of foam such as silicone, or a brush with nylon, rayon, etc. implanted. Further, the developing sleeve 3 of the elastic roller 5
It is desirable that the contact width between the elastic roller 5 and the developing sleeve 3 is 60 to 200 mm / sec. In this embodiment, as the elastic roller 5, a brush having an outer diameter of 14 mm is used, which is obtained by coating a core metal having a diameter of 6 mm with polyurethane foam (trade name: malt filter) in a roller shape. The contact width with the developing sleeve 3 is 4 mm,
The relative speed with respect to was set to 100 mm / sec.

Non-magnetic toner 6 which is a non-magnetic one-component developer
Is a pigment such as carbon dispersed in a thermoplastic resin such as styrene resin, acrylic resin, or polyethylene resin. In this embodiment, 1.0% of colloidal silica is added to toner powder having an average particle size of 10 μm, which is composed of a copolymer of styrene / acrylic resin and styrene / butadiene resin and a pigment.
Was used as a positive polarity toner.

The lower seal member 7 is preferably a flexible thin seal such as urethane or PET. In this example, PET (product name Mylar) having a thickness of 30 μm was used as the lower seal member 7.

In the developing device having the above-described structure, as described above, when the elastic roller 5 rotates in the direction of the arrow c, the toner 6 in the developing container 2 is carried on the developing sleeve 3, and the elastic blade 14 and the developing blade 3 develop. It is frictionally charged at the contact portion with the sleeve 3. The charged toner 6 escapes from the contact portion between the elastic blade 14 and the developing sleeve 3, and is formed as a thin layer of the toner 6 on the developing sleeve 3, and the photosensitive drum 1
Then, the sheet is conveyed to the developing section which is opposed to the developing section with a minute gap. Then, in the developing section, by applying an alternating voltage, in which a direct current and an alternating current are superposed, as a developing bias between the developing sleeve 3 and the photosensitive drum 1, the toner 6 on the developing sleeve 3 becomes an electrostatic latent image on the photosensitive drum 1. Corresponding to the transfer, adhesion,
The electrostatic latent image is developed and visualized as a toner image.

On the other hand, the toner remaining on the developing sleeve 3 without being consumed for development in the developing section is the developing sleeve 3
With the rotation of, the toner is collected in the developing container 2 from the lower part of the developing sleeve 3. As described above, the toner collecting portion of the root developing container 2 is provided with the seal member 7, which allows the toner 6 remaining on the developing sleeve 3 to pass into the container 2 and the inside of the container 2. Of the toner 6 is prevented from flowing out from the lower portion.

Toner 6 collected in the developing container 2
Is peeled off from the developing sleeve 3 at the contact portion with the developing sleeve 3 by the elastic roller 5. Elastic roller 5 at the same time
The new toner 6 is supplied onto the developing sleeve 3 by the rotation of, and the new toner 6 is conveyed to the contact portion between the developing sleeve 3 and the elastic blade 14 as the developing sleeve 3 rotates again. Further, most of the peeled toner 6 is conveyed into the toner 6 in the developing container 2 by the rotation of the elastic roller 5 and mixed with each other, and the charged electric charge of the peeled toner 6 is dispersed.

The elastic blade 14 which is a feature of the present invention will be described in detail. The elastic blade 14 is formed by integrally heat-bonding a silicone rubber elastic layer 14a that comes into contact with the developing sleeve 3 and a SUS thin plate support layer 14b that is the backing thereof, and dry silica is used as a reinforcing agent in the silicone rubber. Has been added. The amount of dry silica added is 8 to 30 parts by weight per 100 parts by weight of the polysiloxane polymer, which is the raw material for the silicone rubber.

The inventors of the present invention formed an elastic blade by changing the material and the amount of silica added to the silicone rubber, and the average triboelectric charge amount of the toner on the developing sleeve and the image when the elastic blade was used. The density, fog reflectance, and other image quality were evaluated. The fog reflectance is defined as 100% toner reflectance when the entire surface is covered with toner. As a result, when the dry silica is used and the addition amount is within the range of 8 to 30 parts by weight with respect to 100 parts by weight of the siloxane polymer, even if the elastic blade is used for a long period of time, the positive toner on the developing sleeve 3 can be prevented. It was found that the average triboelectrification amount can be maintained at an appropriate value, and the abrasion resistance can be improved and scratches on the rubber surface can be effectively prevented.

FIG. 2 is a graph showing the relationship between the amount of dry silica and wet silica added to the silicone rubber of the elastic blade and the average triboelectric charge amount of the toner on the developing sleeve regulated by the elastic blade. . FIG. 3 is a graph showing image density and fog reflectance when a large number of images are formed using an elastic blade containing dry silica. The amount of dry silica added is 5, 20 and 40 parts by weight. Further, Table 1 shows the results of chipping, abrasion and surface scratches of the elastic blade after the image formation of 3000 sheets when the same amount of dry silica as in FIG. 3 was added.

[0036]

[Table 1]

As is apparent from FIGS. 2 and 3 and Table 1,
When the amount of dry silica added to the silicone rubber of the elastic blade is 8 to 30 parts by weight, the triboelectric charge amount of the positively chargeable toner regulated by the elastic blade and the like are stable at sufficient values, and Reduction of chipping and wear of the elastic blade has also been realized.

The charging polarity of the silicone rubber increases as the amount of the dry silica having a stronger negative charging property than that of the polysiloxane polymer having a strong negative charging property, which is a raw material of the silicone rubber, is increased. This phenomenon is more prominent than the case of using wet silica in which OH ⁻ groups are densely present on the silica surface, which is a sufficient value for the toner charge amount of 15 μm.
C / g is easily obtained.

However, when the amount of silica added is less than 8 parts by weight, as shown in FIG. 2, the average triboelectrification amount is low and fog is liable to occur, and the rubber strength is also lowered, so that chipping and abrasion are caused. It is easy to occur. On the other hand, when the amount of silica added exceeds 30 parts by weight, the average triboelectric charge amount becomes excessive, and as shown in FIG. 3, when a large number of images are formed, a low image density due to charge-up and reversal fog are likely to occur. Moreover, since the rubber hardness of the elastic blade increases, uneven contact with the developing sleeve easily occurs. Therefore, the addition amount of dry silica is 8 to 3
Considering the change in the density of 0 parts by weight, which is the most noticeable change due to the image formation of a large number of sheets, it is preferably 10 to 20 parts by weight.

As described above, the elastic blade 14 according to the present embodiment has a structure in which the silicone rubber elastic layer 14a abutting on the developing sleeve 3 and the SUS thin plate supporting layer 14b lining the same are integrally heat-bonded. In this example, the thickness of the silicone rubber elastic layer is 0.4 mm, SUS
The thickness of the stainless steel thin plate was 0.06 mm. The amount of dry silica added to the silicone rubber was 20 parts by weight with respect to 100 parts by weight of the raw polysiloxane polymer. The rubber hardness was 60. A part of the silicone rubber elastic layer was brought into surface contact with the developing sleeve at a linear pressure of 5 to 200 g / cm.

This linear pressure is measured when three thin plates made of stainless steel or the like having a known coefficient of friction are stacked, inserted between the contact portions of the elastic blade and the developing sleeve, and the central one is pulled out by a spring measurer. It was calculated from the applied load and the coefficient of friction of the thin plate.

By incorporating the developing device having the above-mentioned configuration into an FC-1 copying machine manufactured by Canon, an AC voltage of 1800 Hz and a peak-to-peak voltage of 1200 V is applied to an AC voltage of -399 V.
A developing bias superposed with the DC voltage was applied to the developing sleeve to develop the latent image on the photosensitive drum by the non-contact developing method. The potential of the latent image is -600V for dark areas and -150 for bright areas
Set to 0V and set the distance between the developing sleeve and photosensitive drum to 20V.
It was set to 0 μm.

As a result, about 30 μm is left on the developing sleeve.
A uniform toner coating layer was obtained, and the charge amount of the toner was measured by the blow-off method. The charge amount was +18 μC.
/ G. This charge amount is a value sufficient to obtain a good image. The image obtained was of good quality with a reflection density of 1.3.

When 3,000 sheets of continuous images were formed, the toner charge amount was 15 μC / g to 20 μC / g.
Was maintained, and a good image without sleeve ghost, density reduction, and fog could be obtained until the final image formation. Further, the elastic blade was not chipped or worn.

Further, when development was carried out in a low humidity environment using a toner of the same kind as the above-mentioned toner and a small diameter having an average particle diameter of 8 μm, an abnormal increase in the triboelectric charge amount of the toner was reached until the image formation of 2000 sheets. No charge, +18 μC / g to +2
The image was maintained at 2 μC / g, had no low density, and had no fog.

Another embodiment of the developing device of the present invention will be described. The present embodiment is characterized in that silica whose surface is chemically methylated and hydrophobically treated is added to the silicone rubber of the elastic blade.

The hydrophobically treated silica can improve the triboelectric charge imparting ability of the elastic blade with respect to the toner even if the amount thereof added to the silicone rubber is smaller than that of the dry type silica. Therefore, the addition amount is reduced to reduce the hardness of the elastic blade. Therefore, the uniformity of the contact of the elastic blade with the developing sleeve can be improved. Furthermore, since it is a hydrophobically treated silica, the triboelectric charge imparting ability of the elastic blade can be improved to the same level as in normal humidity even in a high humidity environment, and the environmental stability of the elastic blade can be secured.

FIG. 4 shows the relationship between the amount of the hydrophobically treated silica added to the silicone rubber of the elastic blade and the average triboelectric charge amount of the toner on the developing sleeve regulated by the elastic blade. Also, the amount of hydrophobically treated silica added is 10 and 30.
300 parts by weight, when the amount of dry silica added is 10 parts by weight
Table 2 shows the image density and fog reflectance when forming 0 images.

[0049]

[Table 2]

As shown in FIG. 4 and Table 2, in the case of the hydrophobically treated silica, the range of the proper addition amount is 5 to 3 with respect to 100 parts by weight of the polysiloxane polymer as the raw material of the silicone rubber.
It is 0 part by weight, preferably 5 to 15 parts by weight. In this example, the amount of hydrophobically treated silica added was 10 parts by weight.

Still another embodiment of the developing device of the present invention will be described. This embodiment is characterized in that the dry-silica-added elastic blade described in the first embodiment is used in a developing device using a one-component magnetic developer.

As shown in FIG. 5, the developing device of the present embodiment has a plurality of magnetic poles inside the developing sleeve 3 installed in the developing container 2 containing the magnetic toner 6 which is a one-component magnetic developer. A magnetic roller 9 is provided, and the magnetic toner 9 is magnetically attracted to the developing sleeve 3 by the magnet roller 9, and the magnetic force is also used in the developing portion to prevent toner from adhering to the non-developing portion of the photosensitive drum 1. while doing,
Development can be performed.

In FIG. 5, reference numeral 10 is a stirring member for stirring and supplying the toner 6 in the developing container 2 to the developing sleeve 3.

Also in this embodiment, the elastic blade 14 is used.
Is a silicone rubber elastic layer 1 that contacts the developing sleeve 3.
4a and its backing SUS thin plate support layer 14b are integrally heat-bonded. The elastic blade 14 is brought into contact with the developing sleeve 3 at a position slightly displaced from the magnetic pole N1 of the magnet roller 9, and the magnetic field of the magnetic pole N1 is used to regulate the layer thickness of the toner 6 on the developing sleeve 3. Has become.

As described above, in the developing device of this embodiment, unlike the developing device using the non-magnetic toner, the magnetic field is utilized to satisfactorily control the toner layer thickness and the toner does not adhere to the non-developing portion. Since good development can be performed, the range of the amount of silica added to the silicone rubber is expanded.

That is, even if the amount of silica added to the silicone rubber is small and the charge imparting performance of the elastic blade is deteriorated, the toner having a small triboelectric charge amount is transferred onto the developing sleeve by utilizing the magnetic force in the developing section. Even if the amount of silica added is large and the rubber hardness rises, and the contact nip with the developing sleeve is reduced or uneven contact is likely to occur, the magnetic field is used to roll the toner on the developing sleeve. As a result, the application of toner onto the developing sleeve can be optimized.

From the above, when the magnetic toner is used, the amount of dry silica added to the silicone rubber is 5 to 5.
It is optimized within the range of 40 parts by weight.

In this embodiment, when the image was formed on 3000 sheets by using the developing apparatus shown in FIG. 5 for development, the density was 1.4 and the fog reflectance was 1.0 until the final image formation.
% Maintained. At that time, the triboelectric charge amount of the toner on the developing sleeve was 15 μC / g, which was a sufficient value.

[0059]

As described above, in the developing device of the present invention, the elastic regulating member made of silicone rubber is used as the regulating member for the positive electrode charging one-component developer, and the dry silica is contained in the rubber. Was added in an amount of 8 to 30 parts by weight per 100 parts by weight of the polysiloxane polymer as a rubber raw material, so that the regulating member can impart sufficient triboelectric charge to the one-component developer on the developer carrying member, and It is possible to simultaneously satisfy the characteristics such as releasability to a developer, abrasion resistance, and mechanical strength. As a result, it is possible to form a thin layer of the developer which is well charged for a long period of time and to use it for the development, and it is possible to stably maintain a high quality image by the development.

Further, instead of dry silica, when hydrophobically treated silica whose surface is hydrophobized by methylation or the like is added, it is possible to improve the environmental stability of the triboelectric charge imparting ability of the elastic regulating member to the toner.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of an embodiment of a developing device of the present invention.

FIG. 2 is a graph showing the relationship between the amount of dry silica and wet silica added to the silicone rubber of the elastic blade and the average triboelectric charge amount of the toner on the developing sleeve regulated by the elastic blade.

FIG. 3 is a graph showing image density and fog reflectance when an elastic blade containing dry silica is used.

FIG. 4 is a graph showing the relationship between the amount of hydrophobically treated silica added to the silicone rubber of the elastic blade and the average triboelectric charge amount of the toner on the developing sleeve regulated by the elastic blade.

FIG. 5 is a sectional view showing a schematic configuration of another embodiment of the developing device of the invention.

FIG. 6 is a sectional view showing a schematic configuration of a conventional developing device.

[Explanation of symbols]

 1 Photosensitive Drum 2 Developing Container 3 Developing Sleeve 4 Elastic Blade 5 Elastic Roller 6 Toner 7 Sealing Member 9 Magnet Roller 14 Elastic Blade 14a Silicone Rubber Elastic Layer 14b SUS Thin Plate Support Layer

Claims (3)

[Claims] 1. An elastic regulating member in which a positive-electrode-charged non-magnetic one-component developer carried on a developer carrier and conveyed to a developing area facing the image carrier is brought into contact with the developer carrier. In the developing device that regulates the amount of the developer on the developer carrying member and frictionally charges the developer to the positive polarity, at least a portion of the elastic restricting member that is in contact with the developer carrying member is silicone. 8 to 30 per 100 parts by weight of the rubber raw material formed in the silicone rubber
A developing device, characterized in that dry silica is added in an amount of part by weight. 2. An elastic regulating member in which a positive-electrode-charged non-magnetic one-component developer carried on a developer carrier and conveyed to a developing area facing the image carrier is brought into contact with the developer carrier. In the developing device that regulates the amount of the developer on the developer carrying member and frictionally charges the developer to the positive polarity, at least a portion of the elastic restricting member that is in contact with the developer carrying member is silicone. 5 to 30 per 100 parts by weight of the rubber raw material formed in the silicone rubber
A developing device, characterized in that a part by weight of hydrophobically treated silica is added. 3. A magnetic one-component developer having a positive charging property, which is carried on a developer carrying member and is conveyed to a developing area facing the image carrying member, by an elastic regulating member abutting on the developer carrying member. In a developing device that regulates the amount of the developer on the developer carrier and frictionally charges the developer to the positive polarity, at least a portion of the elastic regulation member that is in contact with the developer carrier is silicone rubber. And a dry silica of 5 to 40 parts by weight per 100 parts by weight of the rubber raw material is added to the silicone rubber.