JP2000162865A - Developing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a good image over a long period of time by restricting the quantity of toner on the surface of a toner carrier by bringing a restricting member into a pressurized contact with the surface of the toner carrier, and at the same time if this toner is charged by friction, by keeping the toner appropriately electrified over a long period of time, even when image formation is carried out at high speed and preventing fixing of the toner to the surface of the restricting member. SOLUTION: In this developing equipment, it is constituted so that the quantity of the toner on the surface of the toner carrier is restricted, by having the restricting member 12 brought into a pressurized contact with the surface of the toner carrier which carries the toner to the image carrier and this toner is charged by friction. In this case, a plated layer 122 is provided on the surface of the restricting member 12 and it is set so that the Vickers hardness Hv is within the range of 600 to 900 on the surface of the restricting member 12 provided with the plated layer 122.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine or a printer, and more particularly to a one-component developing system using only toner as a developer. And a developing device in which a regulating member is pressed against the surface of the toner carrier that conveys the toner to the image carrier, and the regulating member regulates the amount of toner on the surface of the toner carrier and frictionally charges the toner. It is.

[0002]

2. Description of the Related Art Conventionally, as a developing device used for an image forming apparatus such as a copying machine or a printer, a two-component developing system using a toner and a carrier as a developer has been known. A one-component developing system using only toner is known.

Here, in the case of a developing device of a two-component developing system, generally, a carrier and a toner are mixed and stirred in the main body of the device to charge the toner, and the developer charged with the toner is magnetized inside. The developer is supplied to a developer conveying member provided with a roller, and the developer is conveyed by the developer conveying member to a development area facing the image carrier, so that the electrostatic latent image formed on the image carrier is developed. Had become.

However, in the case of the above-described developing device of the two-component developing system, a mechanism for mixing and stirring the toner and the carrier is required, and there has been a problem that the size of the device is increased and the cost is increased.

In the case of the above-described two-component developing type developing device, the toner is mixed and stirred with the carrier to be charged. Part adheres to the carrier,
As a result, the carrier is spent, and the charging performance of the carrier with respect to the toner is deteriorated, and there is a problem that the charge amount of the toner changes. In particular, in this developing device,
Since the carrier is used repeatedly for frictional charging of the toner, the carrier gradually becomes spent and deteriorates, thereby gradually lowering the charge amount of the toner, and as a result, fogging occurs in the formed image or the toner is developed. There is a problem that the image forming apparatus is scattered from the apparatus and becomes dirty.

For this reason, in recent years, attention has been paid to a one-component developing type developing device that uses only toner without using a carrier.

Here, as such a developing device of the one-component developing system, a developing device disclosed in Japanese Patent Application Laid-Open No. Sho 52-143831 is generally used. As shown in FIG. A regulating member 12 formed of a plate of stainless steel or the like on the surface of a toner carrier 11 to be conveyed to the body 1
Is pressed, and the toner carrier 11 is
The amount of toner on the surface of the toner carrier 11 is regulated, and the toner on the surface of the toner carrier 11 is frictionally charged.

However, when a plate-shaped regulating member 12 is brought into contact with the surface of the toner carrier 11 as shown in FIG. It has been very difficult to bring the member 12 into stable contact with the surface of the toner carrier 11 in the axial direction at an appropriate pressure.

As a result, the toner supplied to the surface of the toner carrier 11 cannot be appropriately frictionally charged, and the amount of charge of the toner carried to the image carrier 1 is reduced. Fogging occurs. On the other hand, the amount of charge of the toner becomes too high, so that toner is not supplied to the image carrier 1 satisfactorily, and the density of an image to be formed is reduced. In this case, the amount of toner on the surface cannot be appropriately controlled, and the amount of toner conveyed to the image carrier 1 changes, resulting in a problem that density unevenness occurs in an image formed.

When the regulating member 12 is pressed against the surface of the toner carrier 11 to regulate the amount of toner and to frictionally charge the toner, the regulating member 12 is used.
Toner may adhere to and grow on the surface of the toner carrier 11, causing unevenness in the thickness of the toner on the surface of the toner carrier 11, resulting in streak-like noise or uneven density in a formed image. And so on.

Therefore, in recent years, FIGS.
As shown in (A) and (B), at the end on the side where the plate-shaped regulating member 12 comes into contact with the toner carrier 11, the regulating member 12 is moved along the axial direction of the toner carrier 11. The strength of the restricting member 12 is increased by bending the restricting member 12 so that the restricting member 12 is stably brought into contact with the surface of the toner carrier 11 at an appropriate pressure in the axial direction.

However, when the plate-like restricting member 12 made of stainless steel or the like is bent as described above, a crack is generated in the restricting member 12 at the bent portion. When the toner is frictionally charged while controlling the amount of toner by pressing against the toner, a large amount of toner adheres to the crack portion and grows. When the amount is regulated, as in the case described above, the thickness of the toner on the surface of the toner carrier 11 becomes uneven, which causes problems such as streak-like noise and uneven density in the formed image. there were.

For this reason, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 9-222.
As shown in Japanese Patent Publication No. 793, the surface of the regulating member is subjected to electroless nickel plating to smooth the bent portion where the crack has occurred, so that a uniform toner layer can be stably formed on the surface of the toner carrier. Suggested what was done.

However, in recent years, an image is formed at a high speed in the above-described image forming apparatus, and a regulating member having an electroless nickel plated surface as described above is used. When the amount of toner on the surface of the toner carrier is regulated, the nickel plating layer formed on the surface of the regulating member gradually wears, the charge amount of the toner decreases, and fogging or the like occurs on the formed image. Density unevenness occurs, and toner adheres to the nickel-plated layer formed on the surface of the regulating member, and streak-like noise occurs in the formed image, so that a good image cannot be obtained. The problem arose.

[0015]

SUMMARY OF THE INVENTION According to the present invention, a regulating member is pressed against the surface of a toner carrier for conveying toner to an image carrier, and the regulating member regulates the amount of toner on the surface of the toner carrier. An object of the present invention is to solve the above-described various problems in a developing device that frictionally charges the toner.

That is, according to the present invention, in the developing device as described above, the toner supplied to the surface of the toner carrier is regulated by the regulating member having the plating layer on the surface, and the toner is frictionally charged. Even when an image is formed at a high speed, the toner is appropriately charged for a long period of time to prevent fog and density unevenness from occurring in the formed image, and the toner is formed on the surface of the regulating member. It is an object of the present invention to suppress generation of streak-like noise or the like in an image fixedly formed on a plated layer, and to obtain a good image stably.

[0017]

In the developing device according to the present invention, in order to solve the above-mentioned problems, a regulating member is brought into pressure contact with the surface of a toner carrier for conveying toner to an image carrier, and the regulating member is pressed. By regulating the amount of toner on the surface of the toner carrying member, and in a developing device that frictionally charges the toner on the surface of the toner carrying member, a plating layer is provided on the surface of the regulating member,
The Vickers hardness Hv on the surface of the regulating member provided with the plating layer was set to be in the range of 600 to 900.

Here, if the Vickers hardness Hv on the surface of the regulating member provided with the plating layer is less than 600, the abrasion of the plating layer on the regulating member increases,
The amount of toner charged by friction by the regulating member changes, or the pressure regulating the toner changes, causing unevenness in the amount of toner to be conveyed. Noise occurs. On the other hand, Vickers hardness Hv on the surface of the regulating member provided with the plating layer
Exceeds 900, the plating layer of the regulating member does not wear, so that the toner adheres to the plating layer, and the thickness of the toner conveyed by the toner carrier becomes nonuniform. Noise and density unevenness occur.

When the Vickers hardness Hv on the surface of the regulating member provided with the plating layer is set in the range of 600 to 900 as in the developing device of the present invention, the plating layer on the surface of the regulating member has an appropriate range. The amount of toner that is frictionally charged by this regulating member changes or the amount of toner that is conveyed due to a change in the pressure that regulates the toner, even when image formation is performed at a high speed due to wear. And the toner is prevented from sticking to the plating layer of the regulating member. For this reason, in the developing device according to the present invention, the toner is appropriately charged and regulated appropriately for a long time by the regulating member, and fog, density unevenness, and streak-like noise are generated in the formed image. Is prevented.

Here, in adjusting the hardness on the surface of the regulating member provided with the plating layer, the adjustment is performed by providing the plating layer on the surface of the regulating member and then heating the regulating member to an appropriate temperature. When adjusting the Vickers hardness Hv on the surface of the regulating member provided with the plating layer as described above to be in the range of 600 to 900, generally, the regulating member provided with the plating layer is heated at 250 to 400 ° C. Is heated at a temperature in the range of

Further, when a plating layer is provided on the surface of the regulating member pressed against the surface of the toner carrier as in the developing device of the present invention, the surface of the regulating member becomes smooth by the plating layer. When the end portion of the regulating member pressed against the surface of the body is bent along the axial direction of the toner carrier, even if a crack occurs in the bent portion of the regulating member, the surface of the bent portion is smoothed by the plating layer. That is, the toner does not adhere to the surface of the regulating member and grow.

In addition, a negatively charged toner is used as the toner, and the work function on the surface of the regulating member provided with the plating layer is 4.6 e.
V or less, the friction charging series between the surface of the regulating member and the negatively chargeable toner is separated, and the negatively chargeable toner is appropriately charged even in a high-temperature and high-humidity environment to form an image. And fog and density unevenness are prevented from occurring.

Here, in order to set the Vickers hardness on the surface of the regulating member provided with the plating layer in the range of 600 to 900, when the regulating member is heated as described above, an extremely thin oxide film is formed on the surface of the regulating member. Formed and the work function on the surface of the regulating member changes significantly compared to before heating, but this oxide film is immediately scraped off when regulating the toner and does not affect the charge amount of the toner. And the work function on the surface of the regulating member is 4.6 eV
What is necessary is just to make it below.

In the developing device according to the present invention, the plating layer provided on the surface of the regulating member may be any plating layer having a Vickers hardness Hv in the range of 600 to 900 as described above. For example, a nickel-phosphorus composite plating layer, a nickel-copper-phosphorus composite plating layer, a nickel-boron composite plating layer, or the like can be provided.

When the plating layer is provided on the surface of the regulating member as described above, the thickness of the regulating member is 0.5 to 30 μm, preferably 0.5 to 30 μm, in order to keep the surface of the regulating member smooth and sufficiently charge the toner. In addition to the range of 1 to 15 μm, the plating layer has a surface roughness of 0.2 to 3 μm, preferably 0.4 to 1.5 μm.

Also, as a plating layer on the surface of the regulating member,
It is also possible to provide a plurality of plating layers. For example, a wear-resistant surface plating layer having a Vickers hardness Hv of 600 to 900 is provided on the outermost surface, and the work function is 4.6 eV below the surface plating layer. It is also possible to provide the following internal plating layer to ensure abrasion resistance and chargeability for negatively chargeable toner. In this case, the surface plating layer ensures sufficient abrasion resistance, and the work function in the inner plating layer sufficiently appears on the surface, so that the negatively charged toner is appropriately charged. The thickness of the surface plating layer is 0.1 to 3 μm, preferably 0.5 to 3 μm.
The range is 1.5 μm.

The plating layer as described above does not necessarily need to be provided on the entire surface of the regulating member, and may be provided at least on a portion of the surface of the toner carrier which is in contact with the toner.

On the other hand, a metal such as stainless steel can be generally used as a material of the regulating member on which the plating layer is provided, and when a plating layer is provided on the regulating member by electroless plating, a metal such as stainless steel is used. It is not necessary that the adhesiveness with the plating layer is sufficient, and various resin materials and rubber materials having elasticity capable of obtaining an appropriate regulated pressing force can be used.For example, polycarbonate, polyethylene terephthalate, polyamide, Acrylonitrile / butadiene copolymer rubber, styrene / butadiene copolymer rubber, urethane rubber, silicone rubber, epichlorohydrin rubber and the like can be used.

As the toner used in the developing device of the present invention, a known toner that has been generally used can be used. Such a toner contains at least a binder resin and a colorant. I have.

Here, as the binder resin used in the toner, a known resin generally used conventionally can be used, and from the viewpoint of improving the storage stability and fixing property of the toner, the glass transition is not preferred. Point Tg is 55-7
A resin having a temperature of 5 ° C, preferably 58 to 68 ° C, and a softening point of 80 to 170 ° C, preferably 90 to 150 ° C is used. Further, from the viewpoint of improving the dispersibility of the colorant and the anti-offset agent added in the toner and improving the environmental stability as the toner,
It is preferable to use a resin having an acid value in the range of 10 to 40 KOHmg / g. Further, from the viewpoint of toner productivity and the like, the melt index MI value is 3 to 20 (150 ° C./g).
min), for example, it is preferable to use a polyester resin or a urethane modified polyester resin, but it is not particularly limited to these resins.

Further, the colorant used in the above toner is also
Known colorants generally used conventionally can be used. For example, in the case of a black toner, carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, etc. may be used alone or in combination of two or more. In the case of a full-color toner, various known yellow pigments, red pigments, and blue pigments can be used according to the color of the toner. The amount of these colorants added to the toner is such that the colorant is in the range of 1 to 20 parts by weight, preferably 3 to 15 parts by weight, based on 100 parts by weight of the binder resin in the toner. I do.

In the above-mentioned toner, in addition to the above-mentioned binder resin and colorant, if necessary, a charge control agent, an anti-offset agent, a fluidizing agent and the like generally used for the toner may be appropriately used. In an appropriate amount.

In general, it is preferable to use the toner having a volume average particle diameter of 5 to 9 μm. This means that when the volume average particle size is larger than 9 μm,
This is because, while the reproducibility of a high-definition image is deteriorated, when the volume average particle diameter is smaller than 5 μm, the productivity of the toner is deteriorated.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A developing device according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings, and the use of the developing device according to the present embodiment will regulate even a case where an image is formed at a high speed. A comparative example will clarify that the toner is prevented from sticking to the surface of the member and that a good image with less unevenness in density can be stably obtained.

(Embodiment 1) In the developing device according to this embodiment, as shown in FIG. 4, a negatively charged toner 2 is stored as a toner 2 in a toner storage portion 13 of a device main body 10. .

In this embodiment, in order to obtain the above-mentioned negatively charged toner 2, the binder resin has a glass transition point Tg of 65 ° C., a softening point Tm of 140 ° C.
A polyester resin having an acid value of 25 KOHmg / g and a melt index MI value of 3.6 (150 ° C./10 min) was used. And this polyester resin 1
4 parts by weight of carbon black (Raven 1255 manufactured by Colombian Carbon Co.), 3 parts by weight of a charge control agent (S-34 manufactured by Orient Chemical Co.)
Oxidized low molecular weight polypropylene (manufactured by Sanyo Chemical Co., Ltd .: Viscol TS-200) was added at a ratio of 2.5 parts by weight, and these were sufficiently mixed with a Henschel mixer. The kneaded material was allowed to cool by standing, then coarsely pulverized using a feather mill, further finely pulverized using a jet mill, and subjected to air classification to have a volume average particle size of 8.0.
μm of toner particles were obtained. Then, hydrophobic silica (H-200: H-200) is applied to the toner particles.
0) was added thereto, and the mixture was stirred with a Henschel mixer, and negatively charged toner 2 whose surface was treated with hydrophobic silica was used.

Then, by rotating the toner feeding member 14 provided in the toner storage section 13, the negatively charged toner 2 stored in the toner storage section 13 is transferred to the toner carrier 11 side. The toner 2 sent to the toner supply unit 15 and thus sent to the toner supply unit 15 is supplied to the surface of the toner carrier 11 by the toner supply member 16, and the toner carrier thus supplied to the surface is By rotating the body 11, the toner 2 is
The developing unit is guided to a developing unit opposite to the developing unit.

In the course of guiding the toner 2 supplied to the surface of the toner carrier 11 to the developing section facing the image carrier 1 as described above, a plate-shaped end contacting the toner carrier 11 is formed. Is pressed against the surface of the toner carrying member 11 by pressing the regulating member 12 bent away from the toner carrying member 11.
In addition to regulating the amount of the negatively chargeable toner 2 on the surface of No. 1, the negatively chargeable toner 2 is frictionally charged.

Here, in the developing device of the first embodiment, as the regulating member 12, as shown in FIGS. 5A and 5B, a stainless steel plate made of a SUS301 steel plate having a thickness of about 0.1 mm is used. The plate material 121 is used.
After the end contacting the toner carrier 11 in Example 1 was bent as described above, this plate material 121 was electroless nickel-phosphorus plating solution (Topno Colon PA, manufactured by Okuno Pharmaceutical Co., Ltd.).
L) is immersed at 90 ° C. for 18 minutes to form a plating layer 122, which is heated at 250 ° C. for 1 hour to form a 5 μm-thick composite of nickel and phosphorus on the surface of the plate material 121. What used the plating layer 122 formed was used.

Here, the work function and Vickers hardness of the surface of the regulating member 12 on which the plating layer 122 was formed as described above were measured, and the results are shown in Table 1 below. For the work function, the regulating member 12 on which the plating layer 122 was formed was cut into a size of 2 cm × 2 cm, and the contact with the gold electrode was measured using a surface voltmeter (SSVII-10, manufactured by Kawaguchi Electric Works, Ltd.). The potential difference ΔV (eV) was measured, and the work function of gold was set to 4.9 eV, and the work function Wf was calculated from the following equation.
Was measured. Wf (eV) = 4.9−ΔV

The amount of the negatively charged toner 2 supplied to the surface of the toner carrier 11 is regulated by the regulating member 12, and the negatively charged toner 2 is frictionally charged. 2 was led to a developing section facing the image carrier 1, and the toner 2 was supplied to the electrostatic latent image formed on the image carrier 1 to perform development.

(Examples 2 to 4 and Comparative Examples 1 and 2) In each of the developing devices of Examples 2 to 4 and Comparative Examples 1 and 2, the regulating member 12 used in the developing device of the above-described Example 1 is used. Just let me change.

Here, in Examples 2 to 4 and Comparative Examples 1 and 2, when the plating layer 122 is provided on the surface of the regulating member 12, as shown in FIGS.
SUS having a thickness of about 0.1 mm as in the case of the first embodiment.
A stainless steel plate material 121 made of 301 steel plate is used by bending the end of the plate material. This plate material 121 is used as an electroless nickel phosphorous plating solution (Topno Colon PAL manufactured by Okuno Pharmaceutical Co., Ltd.) as in Example 1 above. 18) at 90 ° C during
Then, the plating layer 122 was provided.

Then, when heating the plate material 121 provided with the plating layer 122 as described above, as shown in Table 1 below, at 300 ° C. in the second embodiment, and 3 ° C. in the third embodiment.
50 ° C., 400 ° C. in Example 4, and 20 ° C. in Comparative Example 1.
Heating was performed at 0 ° C. and at 450 ° C. in Comparative Example 2 for 1 hour, respectively, and a plating layer 122 made of a composite of nickel and phosphorus having a thickness of 5 μm was provided on the surface of the plate material 121.

Then, the plating layer 122 is formed as described above.
The Vickers hardness and work function on the surface of each of the regulating members 12 on which was formed were measured in the same manner as in Example 1 above, and the results are shown in Table 1 below.

(Embodiment 5) In the developing device of Embodiment 5, only the regulating member 12 used in the developing device of Embodiment 1 is changed.

Here, in the fifth embodiment, as shown in FIG. 6, as in the case of the first embodiment, the regulating member 12 is made of stainless steel made of a SUS301 steel plate having a thickness of about 0.1 mm. A plate material 121 having a bent end is used, and the plate material 121 is placed in an electroless nickel-phosphorus plating solution (Okuno Pharmaceutical Co., Ltd .: Top Nicolon PAL).
After being immersed at 0 ° C. for 18 minutes to form an internal plating layer 122a having a thickness of 5 μm in which nickel and phosphorus are combined on the surface of the plate material 121, the plate material 121 is further plated with an electroless nickel boron plating solution (Okuno Pharmaceutical Co., Ltd.). An industrial coating: Top Chemialloy 66) is immersed at 90 ° C. for 5 minutes so that a nickel surface plating layer 122b having a thickness of 1 μm is provided on the internal plating layer 122a. did.

Then, as described above, the inner plating layer 1 is formed.
Regarding the regulating member 12 on which the plating layer 22a and the surface plating layer 122b are formed, similarly to the case of the first embodiment,
The Vickers hardness and work function on the surface were measured, and the results are shown in Table 1 below.

Comparative Example 3 In the developing device of Comparative Example 3, only the regulating member 12 used in the developing device of Example 1 was changed.

In this comparative example 3, as shown in FIGS. 5A and 5B, the regulating member 12 has a thickness of about 0.1 mm as in the case of the first embodiment. SU
A stainless steel plate 121 made of S301 steel plate with its end bent is used. This plate 121 is placed in an electroless nickel copper phosphorus plating solution (Okuno Pharmaceutical Co., Ltd .: Top Nicolon CU-55) at 90 ° C. for 30 minutes. The plate material 121 provided with the plating layer 122 is immersed, and the plate material 121 provided with the plating layer 122 is used as it is, provided with a plating layer 122 having a thickness of 5 μm in which nickel, copper and phosphorus are combined on the surface of the plate material 121.
Was not heated.

Then, as described above, the plating layer 122 is formed.
Also in the regulating member 12 in which is formed,
The Vickers hardness and the work function on the surface were measured in the same manner as in the above case, and the results are shown in Table 1 below.

Comparative Example 4 In the developing device of Comparative Example 4, only the regulating member 12 used in the developing device of Example 1 was changed.

In this comparative example 4, as shown in FIGS. 5A and 5B, the regulating member 12 has a thickness of about 0.1 mm as in the case of the first embodiment. SU
A plate made of stainless steel 121 made of S301 steel plate with its end bent is used. This plate 121 is placed in an electroless nickel-iron phosphorous plating solution (Topno Colon FY-1 manufactured by Okuno Pharmaceutical Co., Ltd.) at 90 ° C. for 60 minutes. The plate 121 is provided with a plating layer 122 having a thickness of 5 μm in which nickel, iron, and phosphorus are combined on the surface of the plate 121, and the plate 121 on which the plating layer 122 is provided is not heated. did.

Then, as described above, the plating layer 122 is formed.
Also in the regulating member 12 in which is formed,
The Vickers hardness and the work function on the surface were measured in the same manner as in the above case, and the results are shown in Table 1 below.

Next, the above Examples 1 to 5 and Comparative Examples 1 to 5
No. 4 was developed using a commercially available printer (Epson: L
P9200), and in an environment of high temperature and high humidity of 30 ° C. and 85% humidity, 20 images per minute at a high speed and a black to white ratio (B / W ratio) of 4% were obtained. After 4000 sheets were printed, the toner adhesion to each of the regulating members 12 used in each developing device was evaluated, and the density unevenness in the formed image was evaluated. The results are shown in Table 1 below.

Here, with respect to the evaluation of toner fixation to each regulating member, the state of fixation of toner on each regulating member was checked after printing 4000 sheets. The case where it was fixed was indicated by x.

Regarding the evaluation of the density unevenness in the formed image, the density unevenness in the formed image was visually checked. If no density unevenness was confirmed even after printing 4000 sheets, ○ 4000 sheets The case where density unevenness was confirmed in the middle of printing was indicated by Δ, and the case where density unevenness occurred from the beginning was indicated by x.

[0058]

[Table 1]

As is clear from the results, the plating layer 1
Each of the developing devices of Comparative Examples 1, 3 and 4 using the regulating member 12 having a Vickers hardness Hv of less than 600 on the surface provided with 22 and the regulating member 1 having a Vickers hardness Hv higher than 900
In the developing device of Comparative Example 2 using No. 2, density unevenness occurred in an image formed during printing of 4000 sheets, and in particular, a comparison using a regulating member 12 having a surface work function higher than 4.6 eV. In the developing device of Example 4, the negatively charged toner 2 was not appropriately charged, and density unevenness occurred in an image formed from the beginning. Further, in the developing device of Comparative Example 2 using the regulating member 12 whose surface Vickers hardness Hv was higher than 900, the toner 2 was fixed to the regulating member 12.

On the other hand, the plating layers 122, 122
In each of the developing devices of Examples 1 to 5 in which the Vickers hardness Hv of the surface provided with the a and 122b is in the range of 600 to 900 and the work function of the surface is 4.6 eV or less, the regulating member 12 is used. Even after printing 4,000 sheets, the formed image does not have density unevenness, the toner 2 does not adhere to the regulating member 12, and a good image with less density unevenness is stably obtained. It became so.

[0061]

As described in detail above, in the developing device according to the present invention, a plating layer is provided on the surface of the regulating member which presses the surface of the toner carrier for transporting the toner to the image carrier, and the plating layer is provided. Because the Vickers hardness Hv of the surface of the regulated member was set in the range of 600 to 900,
The regulating member regulates the amount of toner on the surface of the toner carrier and frictionally charges the toner, so that the plating layer on the surface of the regulating member is worn in an appropriate range. A change in the charge amount of the charged toner and an unevenness in the amount of the conveyed toner are suppressed, and the toner does not adhere to the plating layer of the regulating member.

As a result, even when an image is formed at a high speed using the developing device of the present invention, the toner is appropriately frictionally charged by the regulating member and the amount of the toner to be conveyed is regulated uniformly. And fog, density unevenness, and streak-like noise are prevented from being generated in the image, and a good image can be obtained over a long period of time.

Further, as in the developing device according to the second aspect of the present invention, a negatively charged toner is used as the toner, and the work function of the surface of the regulating member provided with the plating layer is 4.6.
If it is less than eV, the difference in the triboelectric series between the surface of the regulating member and the negatively charged toner increases, and the regulating member appropriately charges the negatively charged toner even in a high-temperature and high-humidity environment. As a result, fogging and density unevenness are prevented from occurring in the formed image, and a good image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a state in which a regulating member formed in a plate shape is pressed against the surface of a toner carrier in a conventional developing device.

FIG. 2 is a cross-sectional view of a conventional developing device in which an end of a plate-shaped regulating member that contacts a toner carrier is bent along the axial direction of the toner carrier, and the regulating member is moved to the surface of the toner carrier. FIG. 3 is a schematic explanatory view showing a state in which the pressure contact is made.

FIGS. 3A and 3B are a perspective view and a partially enlarged cross-sectional view of a conventional regulating member in which an end portion on a side in contact with a toner carrier is slightly bent along an axial direction of the toner carrier.

FIG. 4 is a schematic explanatory diagram of a developing device according to the embodiment of the present invention.

FIG. 5 is a perspective view and a partially enlarged cross-sectional view of a regulating member used in each of the developing devices of Examples 1 to 4 and Comparative Examples 1 to 4 of the present invention.

FIG. 6 is a partially enlarged sectional view of a regulating member used in a developing device according to a fifth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 image carrier 2 toner 11 toner carrier 12 regulating member 122 plating layer 122a internal plating layer 122b surface plating layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Machida 2-3-113 Azuchicho, Chuo-ku, Osaka City Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Ichiro Izumi 2-3-3 Azuchicho, Chuo-ku, Osaka City No.13 Osaka International Building Minolta Co., Ltd. F-term (reference) 2H077 AD06 AD13 AE03 EA14 FA14 GA13

Claims (2)

[Claims] A regulating member for pressing the toner on the surface of the toner carrier, the regulating member regulating the amount of toner on the surface of the toner carrier, and a toner on the surface of the toner carrier. In the developing device, the plating layer is provided on the surface of the regulating member, and the Vickers hardness Hv on the surface of the regulating member provided with the plating layer is in the range of 600 to 900. Characteristic developing device. 2. The developing device according to claim 1, wherein
While using a negatively charged toner as the above toner,
A developing device, wherein the work function on the surface of the regulating member provided with the plating layer is 4.6 eV or less.