JP2635600B2 - Cylinder for electrostatic latent image forming drum - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cylinder for an electrostatic latent image forming drum such as an electrophotographic copying machine and a laser printer.

[Conventional technology and its problems]

An electrostatic latent image forming drum used in a conventional electrophotographic copying machine includes a metal drum formed by machining and a photoreceptor layer formed on the surface of the drum. However, this metal drum is expensive, and with the spread of electrophotographic copying machines, there has been a long-awaited demand for easy-to-handle and inexpensive drums for disposable purposes. -124152, JP-A-58-30761, etc., many proposals have been made on resin drums. However, none of these proposals has been put to practical use. this is,
This is because the material or the method of forming a drum according to the conventional proposal cannot obtain sufficient forming accuracy, particularly, smoothness of the drum surface. Among the conventional proposals, JP-A-58-31344 is the only one that touches the surface smoothness (specularity). However, the specularity of the resin cylinder tested is 0.2 μRa.
It is only stated that it is a degree. However, this level of smoothness is practically insufficient.

[Means for Solving the Problems] An object of the present invention is to provide a phenolic resin cylinder having excellent surface smoothness.

The surface smoothness required for the cylinder according to the present invention is 0.1
μRa or less, especially for precise copying
0.08 μRa or less is required.

Using a screw that has a smooth portion at the tip and a cylinder that fits this screw, heat the material to 100-200 ° C in the smooth portion and extrude, mainly using a material that mixes 50-300 parts by weight of filler with 100 parts by weight of phenol resin. By extruding the cylinder by an extrusion method of shaping and hardening to such an extent that the self-shape can be maintained, the present inventors have found that surface smoothness that could not be achieved with a conventional resin cylinder can be obtained, and completed the present invention. .

As the phenolic resin used in the present invention, phenols such as phenol, cresol, xylenol, resorcinol, butylphenol are reacted with formaldehyde aqueous solution, paraformaldehyde, formaldehyde such as trioxane or other aliphatic aldehyde or aromatic aldehyde. Phenol resins, so-called phenol aralkyl resins obtained by reacting phenols with dimethoxyparaxylene, etc., alkenyl phenols such as isopropenyl phenol and acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene, α -Copolymers with copolymerizable monomers such as methylstyrene and acrylonitrile, and the like, and these may be used alone or in combination. In addition, since a drum using an organic photoconductor as a photoreceptor does not detect the presence of ammonia, a phenol resin that is not a hexamine-curable type is preferable for this application,
In particular, it is preferable to use a resol type phenol resin in a proportion of 70% by weight or more.

The filler used in the present invention has a particle size of preferably 100 μm or less, more preferably 60 μm or less, such as wood powder such as cedar cedar, cell pine, cherry bark, coconut shell powder, peach powder, corn core powder, paper- There are organic powders such as pulverized phenolic laminates and finely cured phenolic resin, and inorganic powders such as talc, clay, silica carbon black, graphite, metal powders, etc., and 50 to 300 parts by weight based on 100 parts by weight of resin. ,Preferably
50 to 250 parts by weight are blended. If the amount is less than 50 parts by weight or more than 300 parts by weight, the moldability deteriorates, and it becomes difficult to obtain a cylinder having good shape accuracy.

A curing agent such as hexamethylenetetramine, paraformaldehyde, or epoxy resin is added to the phenol resin as needed. The use ratio of the curing agent is not limited at all, but when using hexamethylenetetramine, paraformaldehyde or the like, it is preferably 5 to 20 parts by weight based on 100 parts by weight of the phenol resin. When using an epoxy resin, the ratio of the hydroxyl group equivalent of the phenol resin to the epoxy group equivalent of the epoxy resin is preferably selected in the range of 0.5 to 2, and when these curing agents are used in combination, a suitable ratio can be appropriately selected. .

In addition, if necessary, commonly used organic fibers such as glass fiber, nylon, and vinylon, mineral fibers such as carbon fiber, wollastonite, and headman fiber, reinforcing materials such as pulp, lubricants, plasticizers, and coloring agents Additives such as a hardening accelerator may be added in a range that does not impair the smoothness of the surface of the obtained cylinder except for extremely coarse particles.

The phenolic resin composition thus obtained can be mixed and sized by a known technique such as a hot roll or a kneader to obtain a molding material.

This molding material is heated to 100 to 200 ° C., preferably 120 to 200 ° C. in the smooth portion using a screw having a smooth portion at the tip and a cylinder adapted to the screw, and the self-shape is maintained after extrusion. Extrusion molding method to form and harden to a surface smoothness of 0.1μRa
The following phenolic resin cylinder can be used. The extrusion molding method according to the present invention is described in, for example, JP-A-59-178235.
No., JP-A-61-16828, JP-A-61-44622, JP-A-61-61628
This is an application of the method disclosed in, for example, -44623.

The phenolic resin cylinder obtained by the present invention not only has excellent surface smoothness but also has excellent shape accuracy such as straightness and cylindricity, and can be practically used as a cylinder for an electrostatic latent image forming drum. . Also, by changing the mixing ratio of carbon black, graphite, metal powder, and the like used as the filler, the conductivity of the obtained cylinder can be controlled.

For example, when carbon black is used, the amount varies depending on the type.
With the above composition, a cylinder having a resistance value of 10 ⁶ Ωcm or less can be obtained. If it is added in an amount of 30% by weight or more, the moldability deteriorates, which is not preferable.

〔Example〕

Examples 1 to 5 About 100 materials blended according to the ratios shown in Table 1 were used.
Kneading about 15 times with a roll heated to ℃ (the other of the pair of rolls is set to about 50 ℃ or about 150 ℃, depending on the material composition), then pulverized and sized by the usual method Thus, a molding material was obtained.

These molding materials were equipped with a water cooling jacket 2D below the hopper, followed by 3D ~ 10D, 11D ~ 16D, 17D ~ 20
D and each part of 21D ~ 24D Was extruded using an extruder having a cylinder having a diameter of 40 mm and an L / D = 24 equipped with a heater for heating, using a screw having a supply unit 5D, a compression unit 11D, a measuring unit 4D, and a smoothing unit 4D.

The temperature of the cylinder each part, C ₁ (0~2D): water-cooled, C
_{2 (3D~10D): 70 ℃,} C 3 (11D~16D): 90 ℃, C 4 (17~20
D): 110 ° C., C ₅ (21 to 24D): 150 ° C., and extrusion molding was performed at a screw rotation speed of 20 rpm. The surface smoothness of the obtained cylinder was measured using Surfcom 554A manufactured by Tokyo Seimitsu.
The measurement was performed under the conditions of a measurement length of 2.50 mm, a stylus diameter of 5 μ, and a cutoff value of 0.8. The results are shown in Table 1.

Comparative Example 1 Extrusion was performed under the same conditions as in Example 1 except that the coconut shell powder was changed to 9 parts in the formulation of Example 1 shown in Table 1. The surface smoothness of the obtained cylinder was measured using a Surfcom 554A manufactured by Tokyo Seimitsu Co., Ltd. with a measurement length of 2.50 mm and a stylus diameter of 5 mm.
When measured under the conditions of μ and a cutoff value of 0.8, a cylinder having a surface smoothness of 0.3 μRa was obtained.

〔effect〕

The cylinder for an electrostatic latent image forming drum according to the present invention has excellent surface smoothness and is therefore valuable in the field of electrophotographic copying machines that require precise copying.

Claims (1)

(57) [Claims] (1) 100 to 25 parts by weight of a phenol resin and 100 to 25 fillers.
Using a material having 0 parts by weight as the main component, a screw having a smooth part at the tip and a cylinder adapted to this screw using an extrusion molding method of shaping and hardening to such an extent that the self-shape can be maintained after extrusion in the smooth part. A cylinder for an electrostatic latent image forming drum, which is formed and has a surface smoothness of 0.1 μRa or less.