JP2000075743A - Cleaning blade for electrophotographic equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To a residual toner and / or a fused toner,
Provided is a cleaning blade for an electrophotographic apparatus having excellent cleaning performance. A cleaning blade for an electrophotographic apparatus comprising a blade member and a support member to which the blade member is bonded via an adhesive, wherein the blade member has a JIS A hardness at 23 ° C of 62 to 60. 80. A cleaning blade for an electrophotographic apparatus, comprising an elastomer having a rebound resilience at 23 ° C. of 5 to 15%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cleaning blade for an electrophotographic apparatus.

[0002]

2. Description of the Related Art According to an electrostatic electrophotographic copying machine using plain paper as recording paper, an electrostatic charge is generally applied to the surface of a photoreceptor by discharging, and an image is exposed thereon to form an electrostatic latent image. Forming, then applying toner of opposite polarity to the electrostatic latent image and developing, transferring the toner image to recording paper, and finally,
Copying is performed by heating and pressing the recording paper on which the toner image has been transferred and fixing the toner on the recording paper.

Therefore, in order to sequentially perform copying on a plurality of recording papers, it is necessary to remove the toner remaining on the surface of the photoreceptor after transferring the toner image from the photoreceptor to the recording paper in the above process. , The removal of such toner is usually
The cleaning is performed by a cleaning blade for an electrophotographic apparatus. The cleaning blade for an electrophotographic apparatus is generally formed of a support member made of a metal plate, a blade member made of an elastomer, and an adhesive layer for joining the support member and the blade member.

In a conventional blade member, for example, a polyurethane blade member has a JISA hardness of 65-8.
0, and a rebound resilience of 20 to 60% is used. In use, when the edge portion of the blade member abutting on the photoreceptor surface rubs against the rotating photoreceptor surface, In general, the surface of the photoconductor is cleaned by vibrating at a minute amplitude and repelling toner particles remaining on the surface of the photoconductor.

In recent years, in the electrophotographic apparatus, as the process speed has been increased, and the functions such as lowering the melting point of the toner and decreasing the particle size have been improved, the cleaning mechanism has been required to fuse the toner to the photosensitive member surface. Is easy to occur. Further, the conventional cleaning by the repelling action is effective for fine particles such as residual toner, but as in the case of the fused toner, the toner is fused to the surface of the photoreceptor in a film form, and the toner becomes huge. In this case, there is a problem in that the cleaning property is low and the fusion of the toner cannot be completely removed, so that the fusion matter is deposited and image defects are likely to occur.

[0006]

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a cleaning blade for an electrophotographic apparatus having excellent cleaning performance on residual toner and / or fused toner. It is.

[0007]

According to the present invention, there is provided a cleaning blade for an electrophotographic apparatus comprising a blade member and a support member to which the blade member is adhered via an adhesive. JIS at ℃
A cleaning blade for an electrophotographic apparatus, comprising an elastomer having an A hardness of 62 to 80 and a rebound resilience at 23 ° C of 5 to 15%. Hereinafter, the present invention will be described in detail.

[0008] The blade member constituting the cleaning blade for an electrophotographic apparatus of the present invention is made of JIS at 23 ° C.
It consists of an elastomer having an A hardness of 62 to 80.
If the JIS A hardness is less than 62, the contact force on the photoreceptor is reduced, and toner slippage may occur.
If it exceeds 80, the surface of the photoreceptor may be damaged due to the hardness of the elastomer itself, so that it is limited to the above range. The JIS A hardness is defined as JIS K73.
This is a value measured by a spring type A hardness tester according to No. 12.

The blade member is made of an elastomer having a rebound resilience at 23 ° C. of 5 to 15%. If the rebound resilience is more than 15%, it may vibrate due to rubbing against the surface of the photoreceptor during use, and may not be able to exhibit a damping action. On the other hand, the rubbing resistance increases, a large torque is required to drive the photoconductor, and problems such as uneven rotation may occur. The rebound resilience is a value measured according to a rebound resilience test of JIS K 7312.

As the above elastomer, the above JIS
It is not particularly limited as long as it has A hardness and the above-mentioned rebound resilience, and examples thereof include polyurethane and silicone rubber. Among these, polyurethane is preferable because an elastomer having low rebound resilience can be easily obtained.

[0011] The polyurethane is produced using a polyol, an isocyanate and a curing agent as raw materials. The polyol is not particularly limited as long as it is generally used for forming a polyurethane, and examples thereof include polyethylene adipate, polybutylene adipate, and polyethylene butylene adipate. The above polyols may be used alone or in combination of two or more.

The above-mentioned isocyanate is not particularly limited as long as it is generally used for the formation of polyurethane. For example, tolylene diisocyanate, 4,4-diphenylmethane diisocyanate (MDI), tolylene diisocyanate, hexamethylene diisocyanate, isophorone Examples thereof include diisocyanate, 1,4-cyclohexane diisocyanate, and isomers thereof. Preferably, 4,4-diphenylmethane diisocyanate (MDI) and isomers thereof are used because a polyurethane having excellent abrasion resistance can be obtained. The above isocyanates may be used alone or in combination of two or more.

As the curing agent, three kinds of mixtures of a high molecular weight polyol, a low molecular weight diol and a low molecular weight triol are preferably used. The high molecular weight polyol is not particularly limited as long as it is generally used for forming polyurethane, and examples thereof include polyethylene adipate (average molecular weight: 2000). The low molecular weight diol is not particularly limited as long as it is generally used for forming a polyurethane.
Examples thereof include 1,4-butanediol, ethylene glycol, diethylene glycol, 1,6-hexanediol, and neopentyl glycol. The low molecular weight triol is not particularly limited as long as it is generally used for forming a polyurethane, and examples thereof include trimethylolpropane and triisopropanolamine.

In producing the blade member made of polyurethane, a polyurethane molding method usually used can be used, and examples thereof include the following methods. First, the dehydrated polyol and the isocyanate are mixed, and the mixture is heated to a temperature of 70 to 14;
The above-mentioned curing agent and the like are added to the prepolymer obtained by reacting at 0 ° C. for 10 to 120 minutes, and the mixture is injected into a mold of a centrifugal molding machine preheated to 150 ° C. and cured for 25 to 50 minutes.
After the curing reaction, by taking out from the mold, a columnar sheet having a thickness of 1 to 3 mm was obtained, and this was taken to have a width of 8 to 40.
The blade member is obtained by cutting into a strip having a length of 220 to 500 mm.

The support member used in the present invention is not particularly limited. For example, a rigid metal, an elastic metal,
Those manufactured from plastics, ceramics and the like can be mentioned. Among these support members, a rigid metal is preferably used. The method of bonding the blade member and the support member is not particularly limited, for example,
Polyamide-based and polyurethane-based hot melt adhesives,
Examples of the method include an epoxy-based and phenol-based adhesive, and among these, an adhesive method using a hot-melt adhesive is preferable.

The cleaning blade for an electrophotographic apparatus having the above characteristics can be obtained by forming a blade member from a polyurethane elastomer having a glass transition point of 15 to 35 ° C., which is the operating temperature range of the cleaning blade. The polyurethane elastomer has characteristics of a large loss tangent (tan δ) and low rebound resilience. The polyurethane elastomer having such properties is obtained, for example, by adjusting the mixing ratio of three kinds of polyols as a curing agent added to the prepolymer.

Since the cleaning blade for an electrophotographic apparatus has the above-described structure, the damping action is not caused by the flipping action due to the sliding and chattering of the blade member, but by the blade member being always in close contact with the photosensitive member surface. Thus, cleaning performance is exhibited. Therefore, according to the present invention, it is possible to provide a cleaning blade for an electrophotographic apparatus, which is capable of cleaning even when toner fused to the surface of the photoreceptor is present and has excellent cleaning properties.

[0018]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 100 parts by weight of polyethylene adipate (average molecular weight: 2000) as a polyol and 121 parts by weight of pure MDI as an isocyanate were mixed and reacted at 70 ° C. for 120 minutes under a nitrogen atmosphere to obtain a polyurethane prepolymer. As a curing agent to the obtained polyurethane prepolymer, a mixture of a high molecular weight polyol, a low molecular weight diol, and a low molecular weight triol having a compounding ratio shown in Table 1 was added,
Inject into the mold of the centrifugal molding machine preheated to 150 ° C.
Take out after curing for 5 minutes, JIS A hardness 64, rebound resilience 5
% (Both in an atmosphere of 23 ° C.) to obtain a polyurethane sheet having a thickness of 2 mm. The obtained polyurethane sheet was 3
The sheet was cut into a size of 20 mm × 15 mm and bonded to a support member made of a plated steel sheet to produce a cleaning blade for an electrophotographic apparatus.

The obtained cleaning blade for an electrophotographic apparatus is mounted on a commercially available plain paper copier (using an organic photoreceptor, at a speed of 10).
Sheet / min), and after copying a total of 4,000 sheets in eight cycles with "A4 length of 500 sheets continuously passed and left for 1 day or more" as one cycle in halftone image copying, The copied image was evaluated by the method shown. Table 1 shows the results
It was shown to.

[0021]Evaluation method of copied image  The copied image was evaluated visually, and further evaluated according to the following criteria.
Judge as a cleaning blade for electrophotographic equipment
Was. ：: A clear copy image was obtained after 4000 sheets were passed.
Was. ×: Disturbed copy image in the middle of 4000 sheets
This has happened. XX: Disturbance occurred in the copied image immediately after the start of paper feeding.

Example 2 A cleaning blade for an electrophotographic apparatus comprising a polyurethane sheet having a JIS A hardness of 63 and a rebound resilience of 14% was obtained in the same manner as in Example 1 except that the curing agent shown in Table 1 was used. . The obtained cleaning blade for an electrophotographic apparatus was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 A cleaning blade made of a polyurethane sheet having a JIS A hardness of 80 and a rebound resilience of 6% was obtained in the same manner as in Example 1 except that the curing agent shown in Table 1 was used. . The obtained cleaning blade for an electrophotographic apparatus was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4 A cleaning blade made of a polyurethane sheet having a JIS A hardness of 80 and a rebound resilience of 15% was obtained in the same manner as in Example 1 except that the curing agent shown in Table 1 was used. . The obtained cleaning blade for an electrophotographic apparatus was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 A cleaning blade for an electrophotographic apparatus comprising a polyurethane sheet having a JIS A hardness of 65 and a rebound resilience of 20% was obtained in the same manner as in Example 1 except that the curing agent shown in Table 1 was used. . The obtained cleaning blade for an electrophotographic apparatus was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 A cleaning blade for an electrophotographic apparatus comprising a polyurethane sheet having a JIS A hardness of 80 and a rebound resilience of 23% was obtained in the same manner as in Example 1 except that the curing agent shown in Table 1 was used. . The obtained cleaning blade for an electrophotographic apparatus was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3 A cleaning blade made of a polyurethane sheet having a JIS A hardness of 60 and a rebound resilience of 14% was obtained in the same manner as in Example 1 except that the curing agent shown in Table 1 was used. . The obtained cleaning blade for an electrophotographic apparatus was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4 An electrophotographic cleaning blade made of a polyurethane sheet having a JIS A hardness of 84 and a rebound resilience of 7% was obtained in the same manner as in Example 1 except that the curing agent shown in Table 1 was used. . The obtained cleaning blade for an electrophotographic apparatus was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0029]

[Table 1]

As described above, when the cleaning blade for an electrophotographic apparatus manufactured in Examples 1 to 4 is actually mounted on a copying machine to perform copying, the performance required as a cleaning blade for an electrophotographic apparatus is sufficiently achieved. It was equipped.

[0031]

Since the cleaning blade for an electrophotographic apparatus of the present invention has the above-described structure, it has excellent cleaning performance even for a fused toner.

Claims (1)

[Claims] 1. A cleaning blade for an electrophotographic apparatus comprising a blade member and a support member to which the blade member is bonded via an adhesive, wherein the blade member has a JIS A hardness at 23 ° C. of 62. A cleaning blade for an electrophotographic apparatus, comprising an elastomer having a rebound resilience at 23 ° C. of 5 to 15%.