JP2853531B2 - Cleaning blade - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning blade for removing toner remaining on an outer peripheral surface of a photosensitive drum of an electrophotographic copying machine or the like.

[0002]

2. Description of the Related Art In an electrophotographic copying machine or the like, copying on transfer paper is performed as follows. That is, the outer peripheral surface of the photosensitive drum having the photoconductor surface layer is uniformly charged, and the outer peripheral surface is exposed through the image to be copied of the copy object to form an electrostatic latent image on the outer peripheral surface. Then, toner is attached to the electrostatic latent image to form a toner image, and this is transferred to copy paper or the like to perform copying. After the copying, as shown in FIG. 2, since the toner 2 remains on the outer peripheral surface of the photosensitive drum 1, it is necessary to remove the residual charged toner.
Has gone by. This cleaning blade 3
As shown in FIG. 1, a plate-like blade member 6 made of an elastic body is attached to one end of a metal plate-like holding member 4 with an adhesive 7. The removal of the residual toner is performed by a physical method in which the plate-shaped blade member 6 comes into contact with the outer peripheral surface of the rotating photosensitive drum 1 to scrape off the toner. The elastic body used to form the blade member 6 includes urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber,
Butadiene rubber and the like are known. Among them, urethane rubber is awarded because it has excellent mechanical properties such as abrasion resistance as compared with other rubbers.

[0003]

In order to completely remove the residual toner, it is necessary that the contact of the blade member on the outer peripheral surface of the photosensitive drum is always kept constant.
However, the urethane rubber blade member has a problem in that the temperature stability is low and good cleaning properties and durability cannot be obtained due to a change in temperature. However, due to the heat generated by the fixing heater, the original exposure lamp, and the drive motor of the electrophotographic copying machine, the heat generated by the friction of the blade member, and the change in the environmental temperature throughout the season and throughout the day, the temperature of the blade member is reduced. About 0 ° C to 50 ° C
Varies over a wide range. Therefore, the urethane rubber blade member has a problem that it is difficult to perform good cleaning under a low temperature condition such as immediately after use in winter or a high temperature condition such as continuous use in summer.

A method for improving the temperature dependency of a urethane rubber blade member is disclosed in, for example, JP-A-63-163.
No. 8685 discloses a polybutylene adipate (PB
A), a polyurethane elastomer obtained from polyhexylene adipate (PHA) or the like is disclosed. This polyurethane elastomer has been awarded as a cleaning blade because of its excellent abrasion resistance. However, knowledge about the durability life of the cleaning property is still insufficient, and it is strongly desired to solve this problem.

The present invention has been made in view of the above circumstances, and has a cleaning member having a blade member formed of urethane rubber having excellent temperature stability and having excellent cleaning properties and durability in a wide temperature range. Its purpose is to provide a blade.

[0006]

To achieve the above object, the present invention provides a cleaning blade provided with a plate-like blade member at one end of a plate-like holding member, wherein the plate-like blade member has the following ( A urethane rubber formed by a curing reaction between a prepolymer comprising A) and (B) and a curing agent, wherein the urethane rubber has a hardness of 60 to 75 (JI
In the range of SA), the tensile strength is set to 300 kg / cm ² or more, and the rebound resilience is set to a range of 20 to 50%. (A) Polyisocyanate. (B) Polybutylene adipate having an average molecular weight of 1500 to 3000 or polyhexylene adipate having an average molecular weight of 1500 to 3000.

[0007]

In order to solve the above problems, the present inventors have conducted a series of studies focusing on polyols, one of the raw materials for urethane rubber. As a result, as the polyol, a prepolymer is prepared using polybutylene adipate or polyhexylene adipate having an average molecular weight in a specific range, and the prepolymer is subjected to a curing reaction using a curing agent, so as to have a hardness in a specific range. A urethane rubber having tensile strength and resilience was formed. The inventors have found that when a blade member is formed using this urethane rubber, a cleaning blade provided with the blade member has excellent cleaning properties and durability in a wide temperature range, and has reached the present invention.

Next, the present invention will be described in detail.

In the present invention, urethane rubber, which is a material for forming a blade member of a cleaning blade, is obtained by curing a prepolymer comprising a polyisocyanate (A) component and a polyol component (B) component having a specific average molecular weight with a curing agent. Let me get it.

The polyisocyanate as the component (A) is not particularly limited, and those generally used for forming a urethane rubber can be used.
Such polyisocyanates include, for example, 4,
4'-diphenylmethane diisocyanate (MDI),
Isophorone diisocyanate (IPDI), 4,4'-
Dicyclohexylmethane diisocyanate (MD with water)
I), trimethylhexamethylene diisocyanate (T
MHDI), tolylene diisocyanate (TDI), carbodiimide-modified MDI, polymethylenephenyl polyisocyanate (PAPI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate (NDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), Examples include paraphenylene diisocyanate (PDI), lysine isocyanate methyl ester (LDI), and dimeryl diisocyanate (DDI). Among them, MDI,
It is preferable to use TODI or the like.

The above component (B), which is a polyol component, comprises:
Polybutylene adipate (PBA) or polyhexylene adipate (PH) having an average molecular weight of 1500 to 3000
A). Thus, by limiting the polyol component, it becomes possible to obtain a urethane rubber having excellent temperature stability. The reason why the average molecular weight is limited to the above range is that when the average molecular weight is less than 1500, the physical properties of the obtained urethane rubber tend to decrease, and when the average molecular weight exceeds 3000, the processing characteristics during the production of urethane rubber are reduced. This is because there is a tendency to decrease.

[0012] A curing agent is used when the components (A) and (B) undergo a curing reaction. As such a curing agent, a polyol is usually used, and preferably a polyol having a molecular weight of 300 or less. Examples of the polyol include glycols. Specifically, ethylene glycol (EG), diethylene glycol (DE
G), propylene glycol (PG), dipropylene glycol (DPG), 1,4-butanediol (14B
D), hexanediol (HD), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol,
Xylene glycol (terephthalyl alcohol), triethylene glycol and the like. Further, in addition to the above glycol, other polyhydric alcohols are used, such as trimethylolpropane, glycerin,
Pentaerythritol, sorbitol and the like.
The mixing ratio of the above (A) component and (B)
The amount is set in the range of 4 to 10 parts, preferably 5 to 8 parts, based on 100 parts by weight of the total amount of the components (hereinafter abbreviated as "part").

As the curing agent, an amine catalyst, preferably triethylenediamine, can be used, if necessary, in addition to the polyol. By using this, the curing time can be shortened.

The urethane rubber, which is a blade member of the cleaning blade, contains the above-mentioned component (A) and component (B).
It is usually prepared by a prepolymer method using components and a curing agent.

The prepolymer method is a method in which a prepolymer is prepared by previously reacting a polyisocyanate and a polyol, and then a curing agent is added thereto to cause a curing reaction to produce a urethane rubber. In particular,
This is performed as described below. That is, the above (A)
The component and the component (B) are mixed to prepare a mixture. The mixing ratio at this time is usually set in the range of 25 to 45 parts of the component (B) with respect to 100 parts of the component (A), and preferably 30 to 4 parts.
The range is 0 parts. The mixture is then brought to a temperature of 80-1.
The reaction is performed at 20 ° C. for a reaction time of 30 to 90 minutes to prepare a prepolymer. The reaction conditions are not limited, and are appropriately determined by the mixing ratio of the components (A) and (B). Then, a curing agent is blended with the prepolymer, and a curing reaction is performed at a temperature of 100 to 150 ° C. for a reaction time of 15 to 60 minutes to obtain a urethane rubber.

The urethane rubber has a hardness of 60 to 7
5 (JIS A), preferably 65 to 70 (JIS
It is necessary to set in the range of A). That is, if it exceeds 75, it becomes too hard and damages the surface of the photosensitive drum, which causes a problem that the life of the photosensitive drum is shortened. Conversely, if it is less than 60, the toner on the drum cannot be completely scraped off, and residual toner may be generated.

The urethane rubber has a tensile strength.
To 300 kg / cm^TwoAbove, preferably 350 kg / c
m^TwoIt is necessary to set above. That is, 300 kg /
cm ^TwoIf it is less than the above, the wear of the cleaning edge increases.
Because.

The urethane rubber must have a rebound resilience in the range of 20 to 50%, preferably 30 to 40%. That is, if it exceeds 50%, the adhesion to the photosensitive drum is deteriorated, and the cleaning property tends to decrease. Conversely, if it is less than 20%, the cleaning property does not follow because it does not follow irregularities on the surface of the photosensitive drum. Because it can be seen.

Next, an example of a method of manufacturing a cleaning blade having a urethane rubber blade member will be described.

That is, first, the metal plate-like holding material 4
Is previously treated with an adhesive. Then, as shown in FIG. 3, one end of the metal plate-shaped holding member 4 is placed in a molding die 9 having a molding space 8 for forming a blade portion on the inner surface of the mold, as shown in FIG. 8. On the other hand, using the components (A) and (B),
A prepolymer is prepared according to the above reaction conditions. The prepolymer and the curing agent are injected into the molding space 8. Then, after a curing reaction under the above-described conditions, this is put into a molding die 9.
1, a cleaning blade having a blade member formed of urethane rubber as shown in FIG. 1 can be obtained.

[0021]

As described above, in the cleaning blade of the present invention, the blade member has an average molecular weight of 1500.
Polybutylene adipate or polyhexylene adipate of ~ 3000 is used as a polyol, and this is reacted with polyisocyanate to prepare a prepolymer, and the prepolymer is formed from a urethane rubber obtained by a curing reaction using a curing agent. The hardness, tensile strength and rebound resilience of the urethane rubber are set in specific ranges. Therefore, since this blade member has excellent temperature stability, it can be cleaned well under high temperature conditions such as during continuous use in summer or under low temperature conditions immediately after the start of use in winter. It has properties and durability. As a result, the electrophotographic copying machine using the cleaning blade of the present invention can obtain a high-quality copy image without contamination for a long period of time.

Next, examples will be described together with comparative examples.

[0023]

Examples 1 to 11 and Comparative Examples 1 to 9 In accordance with the following methods and the proportions shown in Tables 1 to 4, cleaning blades having a blade member made of urethane rubber were produced. That is, first, one end side of the plate-like holding material was treated with an adhesive. As shown in FIG. 3, this is put into a molding die 9 having a molding space 8 for forming a blade portion on the inner surface of the die.
The holding member 4 was arranged so that one end thereof was located in the molding space 8. On the other hand, using the component (A) as a polyisocyanate and the component (B) as a polyol,
A prepolymer was prepared at 60 ° C. for a reaction time of 60 minutes. The prepolymer and the curing agent were injected into the molding space 8 and a curing reaction was performed at a temperature of 120 ° C. and a curing time of 60 minutes. And
This was taken out of the mold 9 to obtain a cleaning blade having a blade member formed of urethane rubber as shown in FIG. In all Examples and Comparative Examples, 1,4'-diphenylmethane diisocyanate (MDI) was used as a polyisocyanate, and 1,4-butanediol and trimethylolpropane were used as curing agents. Comparative Example 5 used polyethylene adipate (PEA) as the polyol, and Comparative Example 6 used polycaprolactone polyol (PCL) as the polyol.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

Examples 1 to 1 obtained as described above
1. The hardness, tensile strength and rebound resilience of the urethane rubber blade members of the cleaning blades of Comparative Examples 1 to 9 were examined. The results are shown in Tables 5 to 8 below. In addition,
The hardness, tensile strength, and rebound resilience are as specified in JIS K6301.
It measured according to. The cleaning blades of Examples 1 to 11 and Comparative Examples 1 to 9 were mounted on an electrophotographic copying machine (NP6030, manufactured by Canon Inc.), and the paper passing durability test was performed at various temperatures (0 ° C., 25 ° C., 50 ° C.). C). The results are also shown in Tables 5 to 8 below. In the above-mentioned paper passing durability test, a sample having 30,000 copies and showing no abnormality such as toner contamination was represented by a circle. In addition, when an abnormality has occurred, the number is shown.

[0029]

[Table 5]

[0030]

[Table 6]

[0031]

[Table 7]

[0032]

[Table 8]

As shown in Tables 5 and 6, the urethane rubber blade members of all the examples were 300 ° C. at both low temperature (0 ° C.), high temperature (50 ° C.) and normal temperature (25 ° C.)
It can be seen that there was no abnormality such as toner contamination even after copying 00 sheets. And, even after copying 30,000 sheets, it had good cleaning properties. On the other hand, from Tables 7 and 8 above, it can be seen that the cleaning blade of the comparative example product had poor cleaning at various temperatures.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a cleaning blade.

FIG. 2 is an explanatory diagram showing a state in which residual charged toner on a photosensitive drum is removed by a cleaning blade.

FIG. 3 is a cross-sectional view showing a blade part forming die of the cleaning blade.

Continuing on the front page (72) Inventor Kazuhide Tsuda, Komaki City, Aichi Prefecture, Kitagaiyama, Gezu 3600 Tokai Rubber Industries Co., Ltd. (56) References JP-A-62-288880 (JP, A) JP-A-5-127575 (JP, A) JP-A-53-93036 (JP, A) JP-A-5-19671 ( JP, A) JP-A-1-105983 (JP, A) JP-A-54-104840 (JP, A) JP-A-63-8865 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , (DB name) G03G 21/10-21/12

Claims (2)

(57) [Claims] 1. A cleaning blade having a plate-like blade member on one end side of a plate-like holding material, wherein the plate-like blade member comprises a prepolymer comprising the following (A) and (B): Is formed by urethane rubber obtained by a curing reaction, and the hardness of the urethane rubber is 60 to 75.
(JIS A), the tensile strength is 300kg / cm
Cleaning blade into ^two or more, impact resilience, characterized in that it is set to the range of 20-50%. (A) Polyisocyanate. (B) Polybutylene adipate having an average molecular weight of 1500 to 3000 or polyhexylene adipate having an average molecular weight of 1500 to 3000. 2. The cleaning blade according to claim 1, wherein the curing agent comprises the following (a) and (b). (A) a polyol having a molecular weight of 300 or less. (B) triethylenediamine.