JP2002236415A - Toner supply roller and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner supply roller having both excellent toner feeding property and unnecessary toner scraping property though it has a soft and smooth surface as a whole and capable of repeatedly forming a uniform toner layer on a developing roller, and to provide an image forming device using the toner supply roller. SOLUTION: This toner supply roller 1 abuts on the developing roller for forming a visible image by feeding toner carried on its surface to an image forming body and supplies the toner to the developing roller. The roller 1 includes a metallic shaft 2 and a urethane foam layer 3 provided on the outer periphery of the shaft 2 by integral molding. The roller 1 has a porous layer 4 which consists of a coating film and whose aperture diameter is 50 to 400 μm on the surface of the layer 3, and the height of the layer 4 to a ridge line in perpendicular projection in the longitudinal direction of the roller is <=100 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller made of urethane foam, and more particularly, to an image forming apparatus such as a copying machine or a printer, which transports toner to an image forming body such as a photoreceptor or paper and makes the toner visible on the surface. A toner supply roller (hereinafter, referred to as a toner supply roller) for supplying toner to a developing roller for forming an image.
(Hereinafter simply referred to as “supply roller”) and an image forming apparatus using the same.

[0002]

2. Description of the Related Art In general, a developing section in an electrophotographic image forming apparatus such as a copying machine or a printer has an image forming body for holding an electrostatic latent image and a developing unit which is in contact with the image forming body and is carried on the surface. A developing roller for visualizing the electrostatic latent image by attaching the toner, and a toner supplying roller for supplying toner to the developing roller. Image formation is performed by a series of processes of transporting the image to the image forming body via the developing roller.

In order to form a good image with this developing mechanism, it is necessary that a thin layer of toner is uniformly formed and carried on the surface of the developing roller without any unevenness. In addition to the above, the performance of the toner supply roller, particularly, the surface performance is important. That is, the toner supply roller comes into contact with the developing roller, and frictionally charges,
It is required to form a uniform toner layer on the surface of the developing roller by supplying and scraping the toner.

Various studies have hitherto been made in order to obtain a toner supply roller having a satisfactory surface performance that satisfies the above requirements. As such a toner supply roller, generally, a urethane roller using urethane foam as a roller material is used.For example, urethane foam is formed integrally with a metal shaft by foam molding in a cylindrical mold.
A method of manufacturing a toner supply roller having a mesh urethane foam layer around a metal shaft is known. In this method, the surface of the urethane foam laminated on the metal shaft is cut into a cylindrical shape by grinding or peeling, so that the mesh of the foam is obtained as a roller surface. In addition, there is a problem that the cost of the polishing or peeling is increased and the equipment investment for the increase is large, which eventually leads to an increase in the product cost.

On the other hand, a metal shaft and urethane foam are integrally formed in a mold in which a molded product has a final shape, and a skin opening ratio on the surface of the molded product is controlled by using a special mold surface. Surface aperture ratio of 20
% Of a urethane supply roller has been proposed (JP-A-9-274373). However, in this method, the surface becomes too smooth, which is inconvenient when the roller has a function of scraping unnecessary toner. As a countermeasure, the roller is parallel to the axis of the surface of the molded product. A structure in which a plurality of grooves are provided has been proposed (JP-A-4-55873, JP-A-11-38749).
No.).

[0006]

However, in this method, it is necessary to increase the concave and convex portions of the groove portion in order to improve the scraping property. When the size of the concave and convex portions exceeds a certain level, the toner becomes uneven. , Irregularities reflected in the image,
There is a problem that image quality is impaired. As another means, there is a method of hardening the resin structure of the foam, but when this method is used, the hardness of the entire roller becomes high, and when it is desired to reduce the pressing pressure to reduce toner damage. It was causing inconvenience.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a flexible and smooth surface as a whole.
Further, it is an object of the present invention to provide a toner supply roller capable of forming a uniform toner layer on a developing roller repeatedly and having an excellent toner conveying property and an unnecessary toner scraping property, and an image forming apparatus using the same. is there.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, in a toner supply roller in which a metal shaft and a urethane foam layer are integrally formed,
By providing a porous layer of a specific structure consisting of a coating film on the surface of the urethane foam layer, it is possible to supply toner with good toner transportability and unnecessary toner scraping property while maintaining the flexibility and smooth surface properties of the entire roller. They found that a roller could be obtained, and completed the present invention. That is, the present invention is as follows.

(1) A toner supply roller that contacts a developing roller that forms a visible image by conveying toner carried on the surface to an image forming body and supplies toner to the developing roller. A toner supply roller including a urethane foam layer provided on the outer periphery of the metal shaft by integral molding, wherein the urethane foam layer has a porous layer having a pore diameter of 50 to 400 μm made of a coating film on the surface thereof. A height of the conductive layer to a ridgeline in a right angle projection in a longitudinal direction of the roller is 100 μm or less.

(2) The toner supply roller according to (1), wherein the urethane foam layer has a cell opening through which the surface of the urethane foam layer communicates from inside.

(3) In the toner supply roller according to the above (1) or (2), the roller hardness as a value obtained by dividing a stress at a pushing amount of 1 mm by an axial pressure contact length is 0.2.
The toner supply roller is within a range of 0.7 N / cm to 0.7 N / cm.

(4) The toner supply roller according to any one of (1) to (3) above, wherein the porous layer is provided by a paint application device having a surface having irregularities.

(5) The toner supply roller according to any one of (1) to (3), wherein the porous layer is provided by spray coating.

(6) In the toner supply roller according to any one of (1) to (5), the coating film has a particle size of 10 μm.
This is a toner supply roller containing the above fillers dispersed therein.

(7) The toner is carried on the surface of the toner supply roller to form a thin film of toner, and the toner supply roller is brought into contact with or close to the image forming body to supply the toner to the surface of the image forming body. An image forming apparatus for forming a visible image, wherein any one of the toner supply rollers (1) to (6) is used as the toner supply roller.

Heretofore, as a technique for improving the surface properties of a toner supply roller by performing coating, a different resin component has been added to a part of a foam to improve the charge amount of a developer and obtain a good image. The roller used is known (Japanese Patent Application Laid-Open No. H10-115977, etc.), and it is also possible to perform coating in a state where it is removed from a cylindrical shape. Compatibility has not been achieved. In addition, the present applicant has proposed a toner supply roller in which the frictional force against paper is specified within a specific range by forming a coating film or the like (Japanese Patent Application No. 2000-254).
563), this technique was intended only to obtain good images. In the present invention, while achieving the balance between the hardness of the supply roller and the toner scraping property, a uniform formation of the toner layer on the developing roller is realized repeatedly, and the toner is adapted to the toner by modifying the surface of the supply roller. An object of the present invention is to provide a supply roller capable of obtaining a good image even after repeated use by enabling control of frictional force.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail. As shown in FIG. 1, the toner supply roller 1 of the present invention includes a metal shaft 2 and a urethane foam layer 3 provided on the outer periphery thereof by integral molding, and further has a porous layer 4 on the surface of the urethane foam layer 3. Are formed. This supply roller 1 is, for example, as shown in FIG.
Can be applied to a non-magnetic one-component developing device schematically shown in FIG.
4 is once carried on the surface of the developing roller 12, and is conveyed to the image forming body 13 via this to be used in a developing process for visualizing an electrostatic latent image.

FIG. 2 is an enlarged partial sectional view of the vicinity of the surface of the supply roller 1 of the present invention. As shown in the drawing, on the urethane foam layer 3 of the supply roller 1, there is a porous layer 4 made of a coating film having an uneven structure. This makes it possible to improve the scraping property of the toner without affecting the hardness and surface properties of the entire supply roller, and to obtain a good toner supply roller capable of maintaining good image quality even when repeatedly used.

The pore size of the porous layer 4 is 50 to 400 μm.
m, preferably 200 to 300 μm. 5 hole diameter
If it is less than 0 μm, it is not preferable because the supply amount of the toner is insufficient. On the other hand, if it is more than 400 μm, the uniformity of the toner supplied on the developing roller is unfavorably deteriorated. The height of the porous layer 4 up to the ridgeline in the right angle projection in the longitudinal direction of the roller is 100 μm or less, preferably 3 μm or less.
0 to 70 μm. If the height exceeds 100 μm, it is not preferable because the uniformity of the toner supplied on the developing roller deteriorates.

The material of the coating film forming the porous layer 4 is not particularly limited. For example, a coating material obtained by dissolving rubber latex such as NBR, urethane, silicone, acryl, nylon resin or the like in a solvent. And a reactive paint which comprises two liquids of a polyol and an isocyanate component and reacts and cures after coating. Further, it is preferable that a filler having a particle size of 10 μm or more is dispersed in the coating film. In this case, the presence of the filler can form the uneven structure of the porous layer 4. As the filler used, for example, polypropylene, polyethylene, nylon, urethane, synthetic resin powder such as silicone, calcium carbonate, inorganic powder such as barium sulfate and the like can be mentioned, as the addition amount, preferably It is in the range of 5 to 50% by weight based on the coating material.

The method for forming the porous layer 4 is not particularly limited as long as a coating film as the porous layer 4 satisfying the above conditions can be formed on the surface of the urethane foam layer 3. It is preferable to use a method of applying a coating applicator having a mesh-like unevenness on the surface thereof by rotating the applied roller against the surface of the urethane foam layer of the formed roller, or a method of applying a spray coating to the formed roller. it can.

Further, in the supply roller 1 of the present invention,
The roller hardness obtained as a value obtained by dividing the stress at the time of the indentation amount of 1 mm by the press-contact length in the axial direction is 0.2 to 0.7 N / c.
It is preferably within the range of m. Roller hardness is 0.7
If it is larger than N / cm, it is not preferable because the toner is not sufficiently transported. On the other hand, if it is less than 0.2 N / cm, it is not preferable because the toner is not sufficiently triboelectrically charged. The roller hardness can be obtained by, for example, a compression test apparatus shown in FIG. 5, and as shown in FIG. It is obtained by dividing by L.

The material of the urethane foam layer 3 is not particularly limited as long as it contains a urethane bond in the resin. Examples of the polyol component include polyether polyol, polytetramethylene ether glycol, T
HF-alkylene oxide copolymer polyols, polyester polyols, acrylic polyols, polyolefin polyols, partially saponified ethylene-vinyl acetate copolymers, phosphate-based polyols, halogen-containing polyols, and the like can be suitably used.

The isocyanate component is not particularly limited, and is generally used for TDI, MDI, crude MDI.
(Polymeric MDI) and modified MDI as well as special isocyanates may be used. Specific isocyanates include, for example, 1,5-naphthalene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, transcyclohexane 1,4 diisocyanate, xylylene diisocyanate (XDI), hydrogenated-XDI, Hydrogenated-MDI,
Lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanate phenyl) thiophosphate, tetramethyl xylene diisocyanate, lysine ester triisocyanate, 1,6,11
-Undecane triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,3
Examples include 6-hexamethylene triisocyanate, bicycloheptane triisocyanate, and trimethylhexamethylene diisocyanate, and these can also be suitably used.

To the urethane foam layer 3, in addition to these polyurethane raw materials, a crosslinking agent, a foaming agent (water, a low-boiling substance, a gaseous substance, etc.), a surfactant, a catalyst and the like can be added.
Thereby, a layer structure as desired can be obtained. In addition, it is also possible to appropriately use a conductive agent such as a flame retardant or a filler, an ionic conductive agent or an electronic conductive agent, a known filler or a cross-linking agent. Examples of the ionic conductive agent include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (eg, stearyltrimethylammonium), benzyltrimethylammonium, and a modified fatty acid dimethylethyl. Ammonium salts such as ammonium perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, ethyl sulfate, carboxylate, sulfonate, lithium, Perchlorates of alkali metals and alkaline earth metals such as sodium, potassium, calcium, magnesium,
Chlorate, hydrochloride, bromate, iodate, borofluoride, trifluoromethyl sulfate, sulfonate and the like can be mentioned.

Examples of the electron conductive agent include conductive carbon such as Ketjen black and acetylene black;
SAF, ISAF, HAF, FEF, GPF, SRF,
Rubber carbon such as FT, MT, etc .; carbon for oxidation-treated ink, pyrolytic carbon, natural graphite, artificial graphite; conductive metal oxides such as tin oxide, titanium oxide, zinc oxide; nickel, copper, silver, Examples thereof include metals such as germanium.

The urethane foam layer 3 has an inner surface.
It is preferable to have a cell opening communicating with the
As a result, the toner is satisfactorily supplied from inside the foam,
The problem of instability of the toner transport amount will be resolved.
You. Preferably, the diameter of the cell opening is 50 to 400 μm.
Yes, and the surface of the urethane foam layer 3 at the opening 1 cm
^TwoIt is preferable that the number per unit is 100 to 1000.
New Urea for obtaining a structure having such a cell opening.
The formation of the tanfoam layer 3 is performed by mixing a polyurethane compound and a release agent.
Can be performed based on the conventional technology.

The integral molding of the urethane foam layer 3 and the metal shaft 2 can be performed, for example, by a cylindrical mold 7 for obtaining a roller shape as a final shape as shown in FIG. That is, after the metal shaft 2 is set as shown in FIG. 3A in a cylindrical mold 7 having a silicone-based releasing agent applied to the inner wall as required, an additive is appropriately added to the above-mentioned polyurethane raw material. By injecting the mixture with
A roller having the shape shown in (b) can be obtained.

The image forming apparatus of the present invention includes the non-magnetic one-component developing device shown in FIG. 4, and may be any apparatus using the toner supply roller of the present invention. There are no particular restrictions on the conditions of the members and the like.

[0030]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. Comparative Example 1 A silicone-based mold release agent was applied to a cylindrical mold 7 having an inner diameter of 16 mm shown in FIG. 3, and a 6 mm-diameter metal shaft 2 was set as shown in the figure. The foam foamable mixture was injected and foamed in a mold to obtain a supply roller made of soft urethane foam. The urethane foam layer of the obtained roller was a communication cell foam having a density of 0.08 g / cm ³ , and the entire surface of the roller also had a uniform communication port.

[0031]

[Table 1]

Example 1 A sheet obtained by slicing urethane foam (ether type, cell diameter 500 μm) to a thickness of 10 mm was subjected to NBR type latex (Nipol LX531 manufactured by Zeon Corporation).
(B: 66% solids), and the supply roller of Comparative Example 1 was rotated in contact with the sheet to form a coating film of NBR latex on the roller surface. This was dried at 100 ° C. for 2 hours to obtain a supply roller of Example 1. The obtained supply roller has a height of 50 μm on the surface.
It had countless convex parts.

Example 2 NBR latex (Nipol, manufactured by Zeon Corporation)
LX551: solid content 45%) Particle size 50 per 100 g
A coating liquid prepared by blending 30 g of a polypropylene powder of 30 μm was applied on the roller of Comparative Example 1 using an iron roll coater, and dried at 100 ° C. for 2 hours.
Was obtained. The resulting roller has a height of 5
It was confirmed that it had countless convex portions of about 0 μm.

Example 3 An NBR latex (Nipol LX531B, solid content 66, manufactured by Zeon Corporation) was applied to the supply roller of Comparative Example 1.
%) To obtain a supply roller of Example 3. On the surface of this roller, countless protrusions having a height of about 30 μm were formed.

The hardness of each supply roller obtained in the above Examples and Comparative Examples was measured according to the following procedure. <Measurement of Roller Hardness> The compression tester AUTO manufactured by Shimadzu Corporation is used to measure the stress when the feed roller is pushed in by 1 mm.
The value was measured by GRAPH AGS-500A, and the value obtained by dividing the measured value by the length of the roller in the axial direction was obtained as the roller hardness.

Each of the supply rollers was mounted on a commercially available laser beam printer, and an image was formed. The initial image and the 100,000th image were evaluated. The evaluation criteria of the image quality are as follows. ：: The image quality is uniform and good in a dark gray solid image. X: Large density reduction and large density unevenness. The results are shown in Table 2 below.

[0037]

[Table 2]

[0038]

As described above, according to the toner supply roller of the present invention, the hardness of the entire roller is changed by applying a coating to the surface of the urethane foam layer to provide a porous layer having a specific structure. This makes it possible to achieve both the toner transportability and the scraping property without causing the problem, and achieves good image durability and image reproducibility. Therefore, according to the image forming apparatus of the present invention using the toner supply roller of the present invention, a good image can be reliably obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a toner supply roller of the present invention.

FIG. 2 is an enlarged partial cross-sectional view near the surface of a toner supply roller of the present invention.

FIG. 3 is a perspective view showing a cylindrical mold for integral molding according to the toner supply roller of the present invention.

FIG. 4 is a schematic view of a non-magnetic one-component developing device according to the present invention.

FIG. 5 is a partial schematic diagram showing a compression test apparatus used for roller hardness measurement according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toner supply roller 2 Gold shaft 3 Urethane foam layer 4 Porous layer 7 Cylindrical mold 12 Developing roller 13 Image forming body 14 Toner

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akira Kusano 1 Kashio-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 2H077 AC04 AD06 FA13 FA22 3J103 AA02 AA12 AA72 EA20 FA30 GA57 GA58 HA18 HA48

Claims (7)

[Claims] 1. A toner supply roller that contacts a developing roller that forms a visible image by conveying toner carried on a surface to an image forming body and supplies toner to the developing roller. A toner supply roller including a urethane foam layer provided on the outer periphery of the metal shaft by integral molding;
It has a porous layer of 0 to 400 μm, and the height of the porous layer to the ridgeline in the orthogonal projection in the longitudinal direction of the roller is 100.
a toner supply roller having a diameter of not more than μm. 2. The toner supply roller according to claim 1, wherein the surface of the urethane foam layer has a cell opening communicating from the inside. 3. A roller hardness as a value obtained by dividing a stress at a pressing amount of 1 mm by a pressing length in an axial direction is 0.2 to 0.2.
The toner supply roller according to claim 1, wherein the toner supply roller has a range of 0.7 N / cm. 4. The toner supply roller according to claim 1, wherein the porous layer is provided by a paint application device having an uneven surface. 5. The toner supply roller according to claim 1, wherein the porous layer is provided by spray coating. 6. The toner supply roller according to claim 1, wherein said coating film contains a filler having a particle size of 10 μm or more dispersedly. 7. A toner is formed on a surface of a toner supply roller by forming a thin film of toner by carrying toner on the surface of the toner supply roller. An image forming apparatus for forming an image, wherein the toner supply roller is used as the toner supply roller.
7. An image forming apparatus using the toner supply roller according to any one of 6.