JP2001194896A - Regulation blade and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regulation blade by which toner can be sufficiently triboelectrified, fusion of the toner due to frictional heat is eliminated and deterioration of image quality due to density unevenness and stripe-shaped unevenness or the like is eliminated. SOLUTION: The regulation blade 1 composed of a planar metallic elastic member regulates layer thickness of a developer 5 by coming into contact with a developing roller 3 and the developer 5 is triboelectrified. Further the planar metallic elastic member 1 is constituted by forming nickel-phosphor composite plating layer 2 in which fluororesin is dispersed at least at a part which is in contact with the developing roller 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regulating blade and an image forming apparatus using the regulating blade.

[0002]

2. Description of the Related Art An image forming apparatus using an electrophotographic system has been used for a copying machine, a laser beam printer, a facsimile machine and the like. Conventionally, as this image forming apparatus,
An apparatus using a one-component developer in which only a developer component is a toner and an apparatus using a two-component developer in which a developer component uses a toner and a carrier are known. Particularly, an image forming apparatus using a one-component developer does not use a carrier, so there is no need to consider the deterioration of the carrier, the mixing ratio between the carrier and the toner, and the like. In recent years, it has become mainstream.

[0003] One-component developers include a magnetic one-component developer using a magnetic toner containing a magnetic substance such as magnetite therein, and a non-magnetic one-component developer using no magnetic toner. The non-magnetic one-component developer is held and supplied to the surface of the developing roller by electrostatic force, is thinned by a regulating blade, and is given a triboelectric charge. The non-magnetic one-component developer does not use a colored magnetic material, so it is easy to cope with colorization, and since no magnet is used for the developing roller, it is possible to reduce the weight and cost. Has begun to be put to practical use in small full-color printers and the like. As the non-magnetic one-component developer, a toner having a relatively high volume specific resistance is used because the toner is forcibly charged and a charge is applied to and adhered to the developing roller. For example, when using a toner of 10 ¹⁰ Ω-cm to 10 ¹³ Ω-cm or more, it is necessary to charge to a predetermined polarity,
A triboelectric charging member applies triboelectric charging.

As the friction charging member, a regulating blade for uniformly regulating the toner on the developing roller to a predetermined layer thickness, and a charging member used only for the frictional charging of the toner are used. Above all, it is easiest to use a regulating blade that regulates the layer thickness of the developer and at the same time charges the developer by frictional charging, and it is possible to reduce the cost. Since the regulating blade needs to be pressed against the developing roller with high accuracy, it is required to have a flatness and a smooth surface roughness. Further, it is required that a sufficient amount of triboelectric charge can be generated and that the developer is not fused by frictional heat. If these requirements are not satisfied, image quality such as density unevenness and streak unevenness deteriorates. Conventionally, a regulating blade has been used in which a thin metal plate such as stainless steel is punched out from the advantage that the pressure contact force with respect to the developing roller is not affected by a temperature change.

[0005]

However, the regulating blade made of a thin metal plate has a problem that the toner broken by the pressure contact stress of the regulating blade is fixed or the toner is fused by frictional heat. In particular, in recent years, the toner itself tends to be required to have excellent color developing properties.
What has been styrene-based has shifted to a polyester-based material having higher transparency. The toner having a polyester-based binder resin has a very high tackiness, and thus causes a problem that the toner easily adheres to the regulating blade.
In addition, the regulating blade made of a thin metal plate has a high frictional resistance, and may be worn by friction with the toner. Once the abrasion occurs, there is a problem that the abrasion is further promoted by abrasion.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and can provide a toner with a sufficient triboelectric charge, does not fuse the toner due to frictional heat, and has uneven density and stripes. It is an object of the present invention to provide a regulating blade which does not deteriorate the image quality due to irregularities in shape and an image forming apparatus using the regulating blade.

[0007]

SUMMARY OF THE INVENTION The present invention is a regulating blade comprising a flat metal elastic member which contacts a developing roller to regulate the layer thickness of the developer and imparts a triboelectric charge to the developer. The plate-like metal elastic member is characterized in that a nickel-phosphorus composite plating layer in which a fluororesin is dispersed is formed at least in a portion in contact with the developing roller. By forming the nickel-phosphorus composite plating layer in which the fluororesin is dispersed at least in a portion in contact with the developing roller, the toner is excellent in non-adhesion and has a low friction coefficient, so that it is not worn by the toner. Further, nickel (hereinafter abbreviated as Ni), which is a metal base material of the nickel-phosphorus composite plating layer, has excellent corrosion resistance and can be used for a long period of time without deterioration of the surface state due to rust or the like.

[0008] Further, nickel-
The thickness of the phosphorus composite plating layer is 0.5 to 25 μm.

The fluorine resin dispersed in the nickel-phosphorus composite plating layer is characterized in that it is a fine powder of 0.05 to 5 μm. The content of the fluororesin is 6 to 20% by weight based on the entire nickel-phosphorus composite plating layer in which the fluororesin is dispersed.

The flat metal elastic member is formed by stamping and forming a stainless steel plate for a spring.

An image forming apparatus according to the present invention comprises a developer accommodating case, a developing roller for carrying the developer accommodated in the developer accommodating case on a surface thereof, and a developer accommodating on the developing roller. A regulating blade for regulating the layer thickness and imparting a triboelectric charge to the developer, wherein the developer is a non-magnetic one-component developer, the developing roller surface is rubber, It is characterized in that the blade is formed of a flat metal elastic member having a nickel-phosphorus composite plating layer in which a fluororesin is dispersed at least in a portion in contact with the developing roller. In an image forming apparatus using a non-magnetic one-component developer, the surface of the developing roller is made of rubber, and by adopting the regulating blade, sufficient triboelectric charge can be imparted to the toner,
There is no fusion of the developer due to frictional heat, and the image quality does not deteriorate due to density unevenness or streak unevenness.

[0012]

FIG. 1 shows an image forming apparatus according to the present invention.
This will be described below. FIG. 1 is a sectional view showing a developing device portion of the image forming apparatus. The developing device has a developing roller 3 and a regulating roller 4 in a developer accommodating case 7, and contains a toner 5. A regulating blade 1 in which a nickel-phosphorus composite plating layer 2 in which a fluororesin is dispersed is formed at least in a portion in contact with the developing roller 3 is pressed against the outer periphery of the developing roller 3. The developer accommodating case 7 has a stirring member (not shown) for stirring the toner 5. The regulating roller 4 supplies the toner 5 as a developer to the developing roller 3, and the regulating blade 1 makes the thickness of the thin toner layer formed on the developing roller 3 constant and charges the toner to a negative polarity. . Then, the electrostatic latent image formed on the photosensitive drum 6 is developed with a thin layer-formed toner on the developing roller 3. The photosensitive drum 6 rotates clockwise, and the developing roller 3 rotates counterclockwise.

The developing roller 3 is made of silicone rubber, NBR, E, or the like containing a conductivity-imparting agent such as carbon black.
It is formed of a rubber material such as PDM, or a metal or ceramic material having a resin coating layer mixed with a conductivity imparting agent. In the combination of the regulating blade 1 and the non-magnetic one-component developer of the present invention, it is preferable that the surface of the developing roller 3 is rubber because the adjustment of the toner layer thickness is easy and the charging characteristics are improved.

The regulating blade 1 is made of a flat metal material as a base material. Examples of the metal material include a stainless steel plate for a spring, a pressed metal plate of a rust-proofed steel plate, stainless steel, a phosphor bronze plate, and an aluminum plate. Among these, stainless steel plates for springs with a tensile strength of 1000 MPa or more
This is preferable because the layer thickness of the developer becomes uniform.

The regulating blade 1 is made of nickel-containing resin in which a fluororesin is dispersed at least in a portion in contact with the developing roller 3.
The phosphorus composite plating layer 2 is formed. For example, in a regulating blade having one end fixed and the other end free,
The free end portion comes into contact with the developing roller, and the composite plating layer 2 is formed on at least the front end portion. The nickel-phosphorus composite plating layer 2 in which the fluororesin is dispersed is formed by performing a plating treatment in a plating solution in which the fluororesin fine powder is dispersed. The plating treatment includes an electroless plating method, an electroplating method, or a combination thereof. In particular, the electroless plating method is simple,
It is preferable because the thickness of the plating layer becomes uniform, the fluororesin can be dispersed, and the nickel-phosphorus composite plating layer can be easily formed.

In the electroless plating method, nickel hyposulfite, an acetic acid agent, a stabilizer, a pH buffer, an appearance adjuster, and a dispersing agent are added to a hypophosphite reduction bath, and a fine powder of fluororesin is further dispersed. Heat the resulting plating solution to about 80 ° C or higher,
In this method, a nickel-phosphorus composite plating layer is formed by immersing a metal material, for example, a stainless steel plate for a spring, in the plating solution. In addition, the electroless plating may be performed directly after degreased and pickled the plated portion of the metal material, but after further zinc displacement plating to further improve the adhesion, the electroless plating is performed. Is also good.

The formation of a nickel-phosphorus composite plating layer in which a fluororesin is dispersed by an electroless plating method is performed by immersion in a heated plating solution until a composite plating having a desired thickness is obtained. The thickness of the composite plating is 0.5
2525 μm. When the layer thickness is less than 0.5 μm, pinholes are generated in the composite plating layer, non-toner adhesion is reduced, and abrasion resistance is also reduced. If the layer thickness is more than 25 μm, the rigidity of the regulating blade becomes unnecessarily high, and there is a risk of toner cracking or the like.

The particle size of the fluororesin fine powder forming the fluororesin-dispersed nickel-phosphorus composite plating layer is 0.05 to 5 μm.
It is preferably from 0.1 to 2 μm, and more preferably from 0.2 to 0.8 μm. If the particle size is smaller than 0.05 μm, it is difficult to handle, and if the particle size is larger than 5 μm,
It becomes difficult to be retained in the nickel-phosphorus layer.

The amount of the fine powder of the fluorine resin contained in the nickel-phosphorus composite plating layer in which the fluorine resin is dispersed is 6 to 20% by weight. If the content is less than 6% by weight, the sliding characteristics are reduced and frictional heat is likely to be generated when pressed against the developing roller. Also,
If it exceeds 20% by weight, it becomes difficult to form a composite plating layer. The mixing ratio of the fine fluororesin powder contained in the composite plating layer can be easily adjusted by changing the amount of the fine fluororesin powder dispersed in the plating solution.

Examples of the fluorine resin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA),
Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTEF) tetrafluoroethylene-ethylene copolymer (ETFE), polyvinylidene fluoride (PV
DF), polyvinyl fluoride (PVF), chlorotrifluoroethylene-ethylene copolymer (ECTFE)
Etc., and one or more of these are appropriately selected. In particular, PTFE is preferable because it is excellent in sliding properties, non-adhesiveness to toner, and other functional aspects, as well as in price, availability, and ease of handling.

[0021]

EXAMPLES Examples 1 to 5 and Comparative Examples 1 to 2 A stainless steel plate (SUS304-CS) having a thickness of 0.1 mm for a spring.
Using P), a rectangular regulating blade having a length of 335 mm and a width of 25 mm was stamped and formed. On the other hand, an electroless nickel-phosphorus plating solution was prepared by adding nickel sulfate, an acetic acid agent, a stabilizer, a PH buffer, an appearance modifier, and a dispersing aid to a hypophosphite reduction bath, and further dispersing a fluororesin fine powder. I got The fluororesin-dispersed electroless nickel-phosphorous plating solution was heated to about 90 ° C. to immerse the regulating blade. By changing the particle size of the fluororesin fine powder to be dispersed, and the immersion time,
A regulating blade having the components of the composite plating layer and the thickness of the plating layer shown in Table 1 was obtained. In Comparative Example 1, the regulating blade was stamped and formed, but no composite plating treatment was applied. In Comparative Example 2, PTFE was formed on the surface after punching.
(Containing 35% by weight of polyamideimide).

The obtained regulating blade was evaluated by the following method. In the evaluation test, a regulating blade to be tested is installed in a developing device of a test copying machine having a developing roller having a rubber surface, and a line chart having an image ratio of 30% is used as an original.
Using plain paper, a copy test was performed on every 5,000 sheets by continuous paper passing up to 20,000 sheets. The developing device was taken out every 5,000 sheets, the state of the regulating blade was checked, and the occurrence of density unevenness and stripe unevenness of the copied paper was visually checked. When the toner was not fixed or fused on the regulating blade, a circle was used. When the toner was fixed or fused, but the density unevenness or streak-like unevenness was not found on the copied paper, the triangle was used. A large amount of toner sticking or fusing was observed, or the density of unevenness or streak-like unevenness of the copied paper was represented by x. The toner used was a non-magnetic one-component developer in which the binder resin was a polyester resin. Table 1 shows the results.

[0023]

[Table 1]

As a result of the evaluation test, the regulating blades of Examples 1 to 5 showed no density unevenness or streak unevenness on the copied paper even after the 20,000-sheet passing test, and showed functionality and durability. Was excellent. In Comparative Example 1 in which the composite plating layer was not formed on the surface, a large amount of toner was adhered or fused to the blade after the 15,000-sheet passing test, and the copied paper was soiled. The subsequent paper passing test was stopped. Comparative Example 2 in which a PTFE film was formed instead of the composite plating
After the 5,000-sheet passing test, no toner adhesion or fusion was observed on the blade, but almost no copied paper was printed. It is considered that the toner was positively charged. For this reason, the evaluation result was represented by x, and the subsequent paper passing test was stopped.

[0025]

The regulating blade according to the present invention is a flat metal elastic member having a nickel-phosphorus composite plating layer in which a fluororesin is dispersed at least in a portion in contact with the developing roller. Does not occur, and does not adhere to toner having a polyester-based binder, and high-quality and highly reliable printing can be obtained. In addition, since the plating process is performed by using the electroless plating method, the regulating blade is extremely easy to manufacture.

Since the nickel-phosphorus composite plating layer in which the fluororesin is dispersed is used as the composite plating layer according to claims 2 to 4, and the flat metal elastic member is a stainless steel plate for a spring, it is broken. The occurrence of the problem that the developer is fixed or fused by frictional heat is further suppressed, and printing with higher image quality and high reliability is obtained.

According to the image forming apparatus of the present invention, in a developing device in which the developer is a non-magnetic one-component type developer and the surface of the developing roller is rubber, the regulating blade is the regulating blade. Printing with high image quality and high reliability can be obtained without stripe unevenness or the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a developing device portion of an image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 regulating blade 2 composite plating layer 3 developing roller 4 regulating roller 5 toner 6 photosensitive drum 7 developer storage case

Claims (6)

[Claims] 1. A regulating blade comprising a flat metal elastic member that contacts a developing roller to control a layer thickness of the developer and imparts triboelectric charge to the developer, wherein the flat metal elastic member is provided. A nickel-phosphorus composite plating layer in which a fluororesin is dispersed is formed at least in a portion in contact with the developing roller. 2. The regulating blade according to claim 1, wherein the nickel-phosphorus composite plating layer has a thickness of 0.5 to 25 μm. 3. The regulating blade according to claim 1, wherein the fluororesin is a fine powder of 0.05 to 5 μm. 4. The method according to claim 1, wherein the content of the fluororesin is 6 to 20% by weight based on the entire nickel-phosphorus composite plating layer in which the fluororesin is dispersed. A regulating blade according to any one of the preceding claims. 5. The regulating blade according to claim 1, wherein the plate-like metal elastic member is formed by stamping a stainless steel plate for a spring. 6. A developer accommodating case, a developing roller for carrying a developer accommodated in the developer accommodating case on a surface thereof, and regulating a layer thickness of the developer carried on the developing roller. An image forming apparatus comprising: a regulating blade that applies a triboelectric charge to the developer; wherein the developer is a non-magnetic one-component developer, the developing roller surface is rubber, and the regulating blade is An image forming apparatus, comprising: the regulating blade according to claim 1.