JP2000162864A - Developing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict 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, which transports the negatively electrified toner to an image carrier and at the same time, to stably obtain a good image with little generation of fogging or unevenness in density, even in an environment of high temperature and high humidity by carrying out appropriate electrification of the negatively electrified toner, when the toner is electrified by friction. SOLUTION: In this developing equipment, the quantity of toner on the surface of a toner carrier is restricted by a restricting member 12, having the restricting member 12 brought into a pressurized contact with the surface of the toner carrier carrying the negatively electrified toner to the image carrier. In this case, a plated layer 122 is provided on the surface of the restricting member 12, so that the toner on the toner carrier is charged through friction. In this case, the work function on the surface of the restricting member 12 provided with the plated layer 122 is set below 4.6 eV.

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. A regulating member is pressed against the surface of the toner carrier for conveying 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 on the surface of the toner carrier. The present invention relates to a developing device.

[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, the toner is charged by mixing and stirring the carrier and the toner in the main body of the device, 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 developing device of the two-component developing system as described above, 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 developing device of the two-component developing system, 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 the toner carrier 11 and grow, thereby causing unevenness in the thickness of the toner on the surface of the toner carrier 11, causing white streak-like noise or density unevenness in an image to be formed. There was a problem such as doing.

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 above case, the thickness of the toner on the surface of the toner carrier 11 becomes non-uniform, causing white streak-like noise and density unevenness in an image to be formed. was there.

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, the regulating member having the surface electrolessly plated with nickel is used to regulate the negatively charged toner supplied to the surface of the toner carrier and to frictionally charge the toner. In this case, the frictional charging series between the negatively charged toner and the nickel plating on the surface of the regulating member is too close to each other, so that the negatively charged toner is not properly charged, especially in a high-temperature and high-humidity environment. The amount of charge of the non-conductive toner is reduced, and fog and density unevenness occur in the formed image.

[0015]

According to the present invention, a regulating member is pressed against the surface of a toner carrier for transporting a negatively charged toner to an image carrier, and the regulating member frictionally rubs the toner on the surface of the toner carrier. It is an object of the present invention to solve the various problems as described above in a developing device that is charged and controls the amount of toner on the surface of a toner carrier.

That is, according to the present invention, in the above-described developing device, the negatively-charged toner supplied to the surface of the toner carrier is regulated by using a regulating member having a plating layer on the surface. In the case where the toner is frictionally charged, the negatively chargeable toner is appropriately charged, and the charge amount of the negatively chargeable toner is reduced even in a high-temperature and high-humidity environment. It is an object of the present invention to prevent fog and density unevenness from being generated in an image, and to stably obtain a good image with less fog and density unevenness.

[0017]

In the developing device according to the present invention, in order to solve the above-mentioned problems, a regulating member is pressed against a surface of a toner carrier for conveying negatively charged toner to the image carrier. In a developing device in which the amount of toner on the surface of the toner carrier is regulated by the regulating member and the toner on the surface of the toner carrier is frictionally charged, a plating layer is provided on the surface of the regulating member. The work function on the surface of the regulating member provided with the layer was set to 4.6 eV or less.

Here, when the work function on the surface of the regulating member provided with the plating layer is set to 4.6 eV or less as in the developing device of the present invention, the friction between the surface of the regulating member and the negatively chargeable toner is adjusted. Even in a high-temperature, high-humidity environment, the negatively charged toner is appropriately charged,
It is possible to prevent fog and density unevenness from occurring in the formed image.

Further, when a plating layer is provided on the surface of the regulating member which is brought into pressure contact with the surface of the toner carrier as in the developing device of the present invention, the surface of the regulating member is smoothened by the plating layer. When the end 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 formed by the plating layer. It becomes smooth, and the toner does not adhere to the surface of the regulating member and grow.

Further, when the Vickers hardness on the surface of the regulating member provided with the plating layer is set to 500 Hv or more, abrasion of the plating layer on the surface of the regulating member is suppressed. Even in a high-humidity environment, the negatively-charged toner is appropriately charged for a long period of time, and fog and density unevenness in an image to be formed are prevented for a long period of time.

Here, the above-mentioned plating layer provided on the surface of the regulating member may be of any type as long as it has a work function of 4.6 eV or less. A copper / phosphorus composite plating layer, a nickel / boron composite plating layer, and 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 preferably 0.5 to 0.5 in order to keep the surface of the regulating member smooth and sufficiently charge the negatively chargeable toner. 30 μm, preferably 1 to 15 μm, and the surface roughness of the plating layer is 0.2 to 3 μm.
m, preferably in the range of 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, by providing a wear-resistant surface plating layer on the outermost surface, and providing an internal plating layer having a work function of 4.6 eV or less under the surface plating layer, It is also possible to ensure abrasion resistance and chargeability for negatively chargeable toner. In this case, while sufficient abrasion resistance is secured by the surface plating layer,
The thickness of the surface plating layer is 0.1 to 3 μm, preferably 0.5 to 3 μm, so that the influence of the work function on the inner plating layer sufficiently appears on the surface and the negatively chargeable toner is appropriately charged. 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, but 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.

Further, as the negatively chargeable toner used in the developing device of the present invention, a known negatively chargeable toner generally used conventionally can be used, and such a toner includes at least a binder resin. And a colorant.

Here, as the binder resin used for the toner, a known resin generally used conventionally can be used, and from the viewpoint of improving the storage stability and fixability of the toner, the glass transition 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.

The colorant used in the toner is
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.

[0031]

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. It will be clarified that a good image with little density unevenness can be stably obtained while giving a comparative example.

(Embodiment 1) In the developing device of this embodiment, as shown in FIG. 4, negatively charged toner 2 is accommodated in a toner accommodating portion 13 in an apparatus main body 10.

In this embodiment, in order to obtain the negatively charged toner 2, the binder resin has a glass transition point Tg of 65.degree. C., a softening point Tm of 140.degree.
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.

At the stage where the toner 2 supplied to the surface of the toner carrier 11 as described above is guided to the developing section opposed to the image carrier 1, an end portion in contact with the toner carrier 11 in a plate shape is provided. Is pressed against the surface of the toner carrier 11 with a pressing force of 7 g / mm, and the above-described negative charging on the surface of the toner carrier 11 is performed by the regulating member 12. The amount of the toner 2 is regulated, and the negatively charged toner 2 is frictionally charged.

In the developing device according to the first embodiment, as the regulating member 12, as shown in FIGS. 5A and 5B, a stainless steel plate made of SUS301 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) for 18 minutes at 90 ° C., and the plate 121 was provided with a plating layer 122 having a thickness of 5 μm in which nickel and phosphorus were combined on the surface thereof.

Here, the work function and Vickers hardness of the surface of the regulating member 12 on which the plating layer 122 was formed 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.

(Embodiment 2) In this embodiment, only the regulating member 12 used in the developing device in Embodiment 1 is changed.

In the developing device of the second embodiment, as shown in FIGS. 5A and 5B, the regulating member 12 has a thickness of about 0, as in the case of the first embodiment. .1
1 mm stainless steel plate made of SUS301 steel plate
The plate 121 is immersed in an electroless nickel-phosphorous plating solution (Top Nicolon NAC, manufactured by Okuno Pharmaceutical Co., Ltd.) at 90 ° C. for 18 minutes, and the surface of the plate 121 is A composite layer of nickel and phosphorus and having a plating layer 122 with a thickness of 5 μm was used.

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

(Embodiment 3) Also in this embodiment, only the regulating member 12 used in the developing device in the above-mentioned Embodiment 1 is changed.

Here, in the developing device of the third embodiment, as shown in FIGS. 5A and 5B, the regulating member 12 has a thickness of about 0 as in the case of the first embodiment. .1
1 mm stainless steel plate made of SUS301 steel plate
The plate 121 is immersed in an electroless nickel copper phosphorous plating solution (manufactured by Okuno Pharmaceutical Co., Ltd .: Top Nicolon CU-55) at 90 ° C. for 30 minutes, and the surface of the plate 121 is bent. Then, a plating layer 122 having a thickness of 5 μm in which nickel, copper and phosphorus are combined was used.

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

(Embodiment 4) Also in this embodiment, only the regulating member 12 used in the developing device in the above-mentioned Embodiment 1 is changed.

Here, in the developing device of the fourth embodiment, as shown in FIG. 6, a SUS3 having a thickness of about 0.1 mm is used as the regulating member 12 as in the case of the first embodiment.
No. 01 stainless steel plate material 121 with bent ends is used, and this plate material 121 is electroless nickel-phosphorus plating solution (Okuno Pharmaceutical Co., Ltd .: Top Nicolon PA)
L) at 90 ° C. for 18 minutes.
Is provided with an internal plating layer 122a having a thickness of 5 μm, in which nickel and phosphorus are combined, on the surface of
1 was immersed in an electroless nickel plating solution (Topno Colon LPH manufactured by Okuno Pharmaceutical Co., Ltd.) at 90 ° C. for 5 minutes, and nickel plating having a thickness of 1 μm was formed on the inner plating layer 122a. A layer provided with the layer 122b was used.

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 work function and Vickers hardness on the surface were measured, and the results are shown in Table 1 below.

(Embodiment 5) Also in this embodiment, only the regulating member 12 used in the developing device in the above-described Embodiment 1 is changed.

Here, in the developing device of the fifth embodiment, as shown in FIG. 6, a SUS3 having a thickness of about 0.1 mm is used as the regulating member 12, as in the case of the first embodiment.
No. 01 stainless steel plate material 121 with bent ends is used, and this plate material 121 is electroless nickel-phosphorus plating solution (Okuno Pharmaceutical Co., Ltd .: Top Nicolon PA)
L) at 90 ° C. for 18 minutes.
Is provided with an internal plating layer 122a having a thickness of 5 μm, in which nickel and phosphorus are combined, on the surface of
To an electroless nickel boron plating solution (Okuno Pharmaceutical Company Limited:
Immersion in top chemical alloy 66) at 90 ° C. for 5 minutes to form a 1 μm-thick surface plating layer 122b composed of nickel and boron on the internal plating layer 122a.
Was used.

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 work function and Vickers hardness on the surface were measured, and the results are shown in Table 1 below.

(Embodiment 6) Also in this embodiment, only the regulating member 12 used in the developing device in the above-mentioned Embodiment 1 is changed.

Here, in the developing device of the sixth embodiment, as shown in FIG. 7, a SUS3 having a thickness of about 0.1 mm is used as the regulating member 12, as in the case of the first embodiment.
A part of the bent side of the plate 121 made of stainless steel made of stainless steel No. 01 is bent in an electroless nickel phosphorous plating solution (Top Nicolon PAL, manufactured by Okuno Pharmaceutical Co., Ltd.). At 18 ° C. for 18 minutes, and a plating layer 122 having a thickness of 5 μm, in which nickel and phosphorus are combined, is formed only on the surface of the plate material 121 at this portion.
Was used.

The work function and Vickers hardness of the regulating member 12 having the plating layer 122 formed on a part of the surface as described above are measured in the same manner as in the first embodiment. The results are shown in Table 1 below.

(Embodiment 7) Also in this embodiment, only the regulating member 12 used in the developing device in the first embodiment is changed.

Here, in the developing device of the seventh embodiment, as the regulating member 12, a resin plate 121 made of polyethylene terephthalate having a thickness of 0.4 mm and having an end bent is used. FIG. 5 (A),
As shown in (B), similar to the case of the first embodiment,
This plate material 121 is placed at 90 ° C. for 18 hours in an electroless nickel phosphorus plating solution (manufactured by Okuno Pharmaceutical Co., Ltd .: Top Nicolon PAL).
For 5 minutes to form a plating layer 1 having a thickness of 5 μm in which nickel and phosphorus are combined on the surface of the plate material 121 at this portion.
22 was used.

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

(Embodiment 8) Also in this embodiment, only the regulating member 12 used in the developing device in the above-mentioned Embodiment 1 is changed.

In the developing device of the eighth embodiment, as shown in FIGS. 5A and 5B, the regulating member 12 has a thickness of about 0, as in the case of the first embodiment. .1
1 mm stainless steel plate made of SUS301 steel plate
The plate 21 was formed by bending the end of the plate 21 and provided with a copper plating layer 122 having a thickness of 5 μm by electroplating on the surface of the plate 121.

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

(Embodiment 9) Also in this embodiment, only the regulating member 12 used in the developing device in the above-mentioned Embodiment 1 is changed.

Here, in the developing device of the ninth embodiment, as shown in FIGS. 5A and 5B, the regulating member 12 has a thickness of about 0 as in the case of the first embodiment. .1
1 mm stainless steel plate made of SUS301 steel plate
The plate 21 was formed by bending the end of the plate 21 and provided with a zinc plating layer 122 having a thickness of 5 μm on the surface of the plate 121 by electroplating.

Then, the plating layer 122 is formed as described above.
Also in the regulating member 12 in which is formed,
The work function and Vickers hardness 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 1) In this comparative example, only the regulating member 12 used in the developing device in the above-mentioned Example 1 was changed.

Here, in the developing device of Comparative Example 1, as the regulating member 12, as shown in FIGS. 3 (A) and 3 (B), a device having no plating layer on the surface is used. Then, the end of a stainless steel plate made of SUS301 steel plate having a thickness of about 0.1 mm was bent in the same manner as in Example 1 described above, and was used as it was.

The work function and Vickers hardness of the surface of the regulating member 12 were measured in the same manner as in Example 1 and the results are shown in Table 1 below.

(Comparative Example 2) In this comparative example, only the regulating member 12 used in the developing device in the above-mentioned Example 1 was changed.

Here, in the developing device of the comparative example 2, as shown in FIGS. 5A and 5B, the regulating member 12 has a thickness of about 0 as in the case of the first embodiment. .1
1 mm stainless steel plate made of SUS301 steel plate
The plate 121 is immersed in an electroless nickel-iron phosphorous plating solution (Top Nicolon FY-1 manufactured by Okuno Pharmaceutical Co., Ltd.) at 90 ° C. for 60 minutes, and the surface of the plate 121 is bent. Then, a composite layer of nickel, iron and phosphorus and a plating layer 122 having a thickness of 5 μm was used.

Then, as described above, the plating layer 122 is formed.
Also in the regulating member 12 in which is formed,
The work function and Vickers hardness 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 3) Also in this comparative example, only the regulating member 12 used in the developing device in the above-mentioned Example 1 was changed.

Here, in the developing device of Comparative Example 3, as shown in FIGS. 5 (A) and 5 (B), the regulating member 12 has a thickness of about 0 as in the case of Embodiment 1 described above. .1
1 mm stainless steel plate made of SUS301 steel plate
The plate 121 is immersed in an electroless nickel plating solution (manufactured by Okuno Pharmaceutical Co., Ltd .: Top Nicolon LPH) at 90 ° C. for 15 minutes, and the surface of the plate 121 is bent. A nickel plating layer 122 having a thickness of 5 μm was used.

Then, as described above, the plating layer 122 is formed.
Also in the regulating member 12 in which is formed,
The work function and Vickers hardness 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 9 and Comparative Examples 1 to
3 is a commercially available printer (Epson: L
P1600), the ratio of black to white (B / W ratio) became 4% at a speed of 6 sheets per minute in an environment of high temperature and high humidity at a temperature of 30 ° C. and a humidity of 85%. After the 3,000 sheets are printed, the toner 2 triboelectrically charged on the surface of the toner carrier 11 by the above-mentioned respective regulating members 12 at the initial stage and after the 3,000 sheets are printed.
And the density unevenness in the formed image was evaluated. The results are shown in Table 1 below.

Here, regarding the charge amount q of the toner 2,
The toner 2 triboelectrically charged on the surface of the toner carrier 11 is sucked by a suction nozzle provided with a filter. At this time, the amount of electric charge Q transferred from the toner carrier 11 is measured by an electrometer, and the toner 2 is sucked. The weight M of the sucked toner was obtained from the difference in the weight of the nozzles, and the charge amount q (= Q / M) of the toner 2 was calculated.

Regarding the evaluation of the density unevenness in the formed image, the density unevenness in the formed image was visually checked, and when no density unevenness was confirmed even after printing 3000 sheets, ○: 3000 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.

[0075]

[Table 1]

As is apparent from the result, the regulating member 1
2 regulates the amount of the negatively chargeable toner 2 on the surface of the toner carrier 11 and
To frictionally charge the plating layers 122, 122
a, the work function on the surface provided with 122b is 4.
Examples 1 to 9 using the regulating member 12 of 6 eV or less
In each of the developing devices, the regulating member 1 in which the plating layer is not provided and the work function on the surface thereof is larger than 4.6 eV.
2, and the plating layer 122 is provided, but compared with the developing devices of Comparative Examples 1 to 3 using the regulating member 12 in which the work function on the surface is larger than 4.6 eV, Was appropriately charged to prevent occurrence of density unevenness in an image to be formed.

In particular, the plating layers 122, 122a, 122
Vickers hardness on the surface provided with b is 500H
In each of the developing devices of Examples 1 to 7 using the regulating member 12 of v or more, the negatively-charged toner 2 is appropriately charged even after printing 3000 sheets, and density unevenness occurs in a formed image. Was prevented from doing so.

[0078]

As described above in detail, in the developing device according to the present invention, the regulating member is pressed against the surface of the toner carrier for transporting the negatively-charged toner to the image carrier, and the regulating member carries the toner. In regulating the amount of toner on the surface of the body and frictionally charging the toner on the surface of the toner carrier, a plating layer is provided on the surface of the regulating member, and the work function on the surface of the regulating member on which the plating layer is provided is determined. Since the difference in the frictional charging series between the surface of the regulating member and the negatively chargeable toner is increased to 4.6 eV or less, the negatively chargeable toner can be appropriately removed by the regulation member even in a high-temperature and high-humidity environment. Became charged.

As a result, in the developing device of the present invention, even in a high-temperature and high-humidity environment, fog and density unevenness are prevented from being formed in a formed image, and a good image can be obtained. Was.

When the Vickers hardness of the plating layer is set to 500 Hv or more, the abrasion of the plating layer is suppressed, and the negatively charged toner can be appropriately charged for a long period of time even in a high-temperature and high-humidity environment. Will be
Generation of fog and density unevenness in an image to be formed is prevented for a long time, and a good image can be obtained for a long time.

[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 shows Examples 1-3, 7-9 and Comparative Example 2 of the present invention.
4A and 4B are a perspective view and a partially enlarged cross-sectional view of a regulating member used in each of the developing devices of FIGS.

FIG. 6 is a partially enlarged cross-sectional view of a regulating member used in the developing devices of Embodiments 3 and 4 of the present invention.

FIG. 7 is a partially enlarged cross-sectional view of a regulating member used in a developing device according to a sixth 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 2-3-13 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 AD17 AE03 EA11 EA15 FA14

Claims (2)

[Claims] A regulating member is pressed against the surface of a toner carrier for transporting a negatively charged toner to an image carrier, the regulating member regulates the amount of toner on the surface of the toner carrier, and regulates the amount of toner on the surface of the toner carrier. Wherein a plating layer is provided on the surface of the regulating member, and the work function on the surface of the regulating member on which the plating layer is provided is 4.6 eV or less. Developing device. 2. The developing device according to claim 1, wherein
A Vickers hardness on the surface of the regulating member provided with the plating layer is 500 Hv or more.