JP3296901B2 - Conductive roll for electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive roll for an electrophotographic device used in an electrophotographic process in an energized state, and in particular, to an electrophotographic device excellent in conductivity without soiling a photosensitive member. The present invention relates to a conductive roll for use.

[0002]

2. Description of the Related Art Electrophotographic processes include charging, latent image formation, development, transfer, fixing, charge elimination, and cleaning. Of these processes, each of charging, development, transfer, and cleaning is performed. In the process,
A conductive rubber roll is used, and a voltage is applied to the roll to perform functions such as charging, developing, transferring, and cleaning. For example, in the charging process, a charging roll to which a voltage is applied is pressed against the surface of the photoconductor to charge the surface of the organic photoconductor (OPC).

Conventionally, as a conductive rubber roll used in an electrophotographic process, a conductive rubber roll having a conductive polyurethane layer formed on its surface is known. This polyurethane layer is provided to prevent its burning. Contains a flame retardant. Flame retardants include an addition type and a reaction type, and as the addition type, organic phosphates, halogen-containing phosphates, and the like are known. These flame retardants can impart self-extinguishing properties to the polyurethane layer of the conductive roll,
Since it is a liquid, it oozes on the surface of the rubber roll and contaminates the organic photoreceptor.

[0004] As reactive flame retardants, phosphorus-containing polyols, halogen-containing polyols and the like are known. Since this reactive type flame retardant is taken into the structure of the polyurethane material, it does not ooze onto the surface of the molded product, so that it does not contaminate the organic photoreceptor. Need to be blended in a large amount. In addition, since the above-mentioned phosphorus-containing polyol and halogen-containing polyol have a small molecular weight, ions are difficult to move, and it is difficult to sufficiently secure the conductivity of the roll. Therefore, there is a problem that each function such as charging in each process of the electrophotographic process cannot be sufficiently exhibited.

[0005]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a conductive roll for an electrophotographic apparatus which does not stain a contact object such as a photoreceptor and has excellent conductivity and flame retardancy.

[0006]

Means for Solving the Problems The present invention has been proposed to achieve the above object, and has the following structure. That is, according to the present invention, in a conductive roll for an electrophotographic apparatus having a conductive polyurethane layer formed on the surface thereof, a metal hydroxide is added to the polyurethane layer. Roles are provided.

Further, according to the present invention, there is provided a conductive roll for an electrophotographic apparatus, wherein the metal hydroxide compounded in the polyurethane is magnesium hydroxide.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The technical feature of the present invention is that a metal hydroxide is added to a polyurethane layer in a conductive roll for an electrophotographic apparatus having a conductive polyurethane layer formed on a surface thereof. This metal hydroxide functions as a flame retardant for polyurethane. Even when blended with polyurethane, it does not ooze onto the surface of the molded product, so that it does not contaminate objects to be contacted, such as photoconductors, and has a conductive property. The present invention can provide a conductive roll for an electrophotographic apparatus having excellent properties.

Hereinafter, the present invention will be described with reference to the drawings.
FIG. 2 shows an example in which the conductive roll for an electrophotographic apparatus according to the present invention is used for a charging roll. A charging roll 14 to which a power supply 12 is connected is pressed against the surface 10A of the photoconductor 10, and the charging roll 14 shown in FIG.
A voltage is applied to the shaft 16 shown in FIG. 3 to adjust the surface 10A of the photoconductor 10 to a desired potential.

The charging roll 14 is formed by forming a conductive polyurethane layer 18 on the surface of a shaft 16 as shown in a sectional view in FIG. A metal hydroxide is added to the polyurethane layer 18 as a flame retardant.

In the present invention, examples of the metal hydroxide used as a flame retardant include magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like. Among these, magnesium hydroxide or aluminum hydroxide is used. Preferably, magnesium hydroxide is used most preferably. It is preferable that magnesium hydroxide is blended in an amount of 5 to 50 phr, particularly 10 to 30 phr in view of physical properties and flame retardancy. If the amount of the metal hydroxide is less than the above range, sufficient flame retardancy cannot be obtained, and if it is more than that, there is no further improvement in flame retardancy, and conversely, Abrasion, permanent set, etc. deteriorate. Since the reaction when decomposed by heating is an endothermic reaction, the metal hydroxide acts to remove heat from the ignited polyurethane layer 18 and extinguish the fire.

In the case of aluminum hydroxide, the amount is preferably 20 to 60 phr, particularly 30 to 50 phr.
, The same physical properties as those of the above magnesium hydroxide can be obtained.

The metal hydroxide of the present invention may be either a hydrate or an anhydride since it can exhibit a function as a flame retardant by the above-mentioned endothermic reaction. This is because the hydrate releases water molecules when heated, and the water molecules inhibit or suppress combustion and improve the function as a flame retardant.

The metal hydroxide used as a flame retardant in the present invention is not a liquid but a crystalline solid.
It does not seep onto the surface of the polyurethane layer 18 and does not contaminate the photoreceptor 10. Further, as described above, since the flame retardancy can be exhibited with a relatively small amount of addition, the conductivity of the polyurethane layer 18 is not deteriorated, and the abrasion resistance and the permanent deformation are not deteriorated.

Further, in the present invention, magnesium hydroxide is most preferred among the metal hydroxides because the decomposition point of magnesium hydroxide is 340 ° C., which is higher than the flash temperature (300 to 320 ° C.) of polyurethane. On the point. That is, if the decomposition point of magnesium hydroxide is higher than the flash point of polyurethane, even if the polyurethane is heated until the flash point is reached, almost no water molecules remain in magnesium hydroxide, and even if the polyurethane layer 18 is ignited, Since a sufficient amount of water is released, a sufficient self-extinguishing property can be imparted to the polyurethane by a synergistic effect of the fire extinguishing effect of the water and the effect of removing heat by an endothermic reaction. In addition,
The above description is about the case where the conductive roll for an electrophotographic apparatus according to the present invention is applied to a charging roll. Is of course generally applicable.

[0016]

According to the present invention, it is possible to provide a conductive roll for an electrophotographic apparatus which does not contaminate an object such as a photoreceptor and has excellent conductivity and flame retardancy.

[0017]

The present invention will be described below by way of examples. Example 1 A polyester-based polyol (OD-X-106, manufactured by Dainippon Ink and Chemicals) was added to lithium perchlorate (LiClO).
₄ ) 0.1 phr was added and the temperature was adjusted to 80 ° C. Next, 5 phr of magnesium hydroxide ("Kisuma 5A" manufactured by Kyowa Chemical Industry Co., Ltd.) was dispersed as a flame retardant, and MDI (diphenylmethane diisocyanate) was added as a curing agent in 10 phr.
phr was added and stirred to obtain a mixture.

This mixture is poured into a mold (having a preheating temperature of the mold of 100 ° C.) in which a shaft is previously arranged, and
It heated at 30 degreeC for 30 minutes, and obtained the roll in which the conductive polyurethane layer was formed in the shaft surface except the both ends. Table 1 shows the physical properties of the roll.

Example 2 A roll was produced in the same manner as in Example 1 except that the amount of magnesium hydroxide ("Kisuma 5A", manufactured by Kyowa Chemical Industry Co., Ltd.) in Example 1 was changed to 10 phr. Table 1 shows the physical properties of the roll.

Example 3 A roll was produced in the same manner as in Example 1, except that the amount of magnesium hydroxide (Kisuma 5A, manufactured by Kyowa Chemical Industry Co., Ltd.) was changed to 30 phr. Table 1 shows the physical properties of the roll.

Example 4 A roll was produced in the same manner as in Example 1 except that the amount of magnesium hydroxide (Kisuma 5A, manufactured by Kyowa Chemical Industry Co., Ltd.) was changed to 50 phr. Table 1 shows the physical properties of the roll.

Example 5 Aluminum hydroxide (manufactured by Showa Denko, "Heidilite H-42") was used in place of magnesium hydroxide in Example 1.
M ") (the addition amount was 30 phr), and a roll was produced in the same manner as in Example 1. Table 1 shows the physical properties of the roll.

Example 6 Aluminum hydroxide (manufactured by Showa Denko, "Heidilite H-42") was used in place of magnesium hydroxide in Example 1.
M ") (the addition amount was 50 phr), and a roll was produced in the same manner as in Example 1. Table 1 shows the physical properties of the roll.

Comparative Example 1 A roll was produced in the same manner as in Example 1 except that magnesium hydroxide was not added. Table 1 shows the physical properties of this roll.
It was shown to.

Comparative Example 2 As a flame retardant, a phosphorus-containing polyol (manufactured by Sanyo Chemical Industries, "Y
A roll was manufactured in the same manner as in Example 1 except that -24 ") was added (addition amount: 10 phr). Table 1 shows the physical properties of the roll.

Comparative Example 3 A phosphorus-containing polyol (Y-24, manufactured by Sanyo Chemical Industries, Ltd.) was mixed with 30
A roll was produced in the same manner as in Example 1 except that phr was added. Table 1 shows the physical properties of the roll.

[0027]

In Table 1, "○" in the column of "self-extinguishing properties" indicates that the self-extinguishing property (extinguishing in 10 seconds or less) is good, and "△" indicates self-extinguishing property (extinction in 30 seconds or less). "X" indicates that there is no self-extinguishing property. In Table 1, “○” in the column of “Bleeding into Photoconductor” indicates that there was no bleeding into the photoconductor. Furthermore, in Table 1, “O” in the columns of “wear resistance” and “compression set” indicates that it is better to compare with the current one.
“X” indicates that the result is worse than the current one.

Comparing the example with the comparative example, especially in the example to which magnesium hydroxide was added, the self-extinguishing property was exhibited with a small addition amount (5 phr), and the addition amount was further reduced within the range up to 50 phr. It is clear that when increased, autolysis is significantly improved. Further, the rolls of Examples 1 to 6 have significantly lower electric resistance and are clearly superior in conductivity as compared with Comparative Examples 1 to 3.

Further, the rolls of Examples 1 to 3 and 5 have excellent abrasion resistance and also have excellent physical properties with respect to compression set. The roll does not exude to the photoconductor,
Summarizing these results, it will be understood that the rolls of Examples 1 to 6 can sufficiently perform functions such as charging and development in the electrophotographic process.

[Brief description of the drawings]

FIG. 1 is a sectional view of a charging roll according to an embodiment of the present invention.

FIG. 2 is a diagram showing a case where the charging roll of FIG. 1 is used in an electrophotographic apparatus, as viewed from an axial direction side of the charging roll.

[Explanation of symbols]

 10 Photoconductor 14 Charging roll (conductive roll for electrophotographic device)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI G03G 15/20 102 G03G 15/20 102 21/06 H01B 5/16 21/10 G03G 21/00 312 H01B 5/16 340 (58 ) Surveyed field (Int.Cl. ⁷ , DB name) C08L 75/04-75/12 F16C 13/00 G03G 15 / 02,15 / 08,15 / 16 G03G 15 / 20,21 / 06,21 / 10 H01B 5/16

Claims (2)

(57) [Claims] 1. A conductive roll for an electrophotographic device having a conductive polyurethane layer formed on a surface thereof, wherein a metal hydroxide is added to the polyurethane layer. 2. The electrophotographic conductive roll according to claim 1, wherein the metal hydroxide is magnesium hydroxide.