JPH05241490A - Conductive cleaning blade - Google Patents

Abstract

PURPOSE:To provide the cleaning blade which can freely control the electric resistance value between a base and a polyurethane sheet and has the electric resistance value meeting respective applications. CONSTITUTION:The conductive polyurethane sheet 2 is adhered via a double- coated adhesive tape 3 or adhesive to a metallic base 1. This base 1 and the conductive polyurethane sheet 2 are conducted by a conductive compsn. 4. The conductive compsn. is preferably a conductive coating material, conductive adhesive or conductive sealant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive cleaning blade, and more specifically,
The present invention relates to a cleaning blade capable of freely controlling the electric resistance value of the cleaning blade itself and imparting the electric resistance value according to the application.

[0002]

2. Description of the Related Art In a dry developing method such as an electrophotographic method or an electrostatic recording method, toner developed on a photoconductor is electrostatically transferred to paper by a transfer process, but adheres to the photoconductor. Not all toner can be transferred,
When this residual toner is carried over to the next cycle,
In the process of exposing the photoconductor, the toner image interferes with the photodischarge of the photoconductor, and the copy obtained thereby becomes an image defect, and a suitable image cannot be developed. Therefore, in order to remove the toner adhering to and remaining on the photoconductor,
Various cleaning methods have been proposed.

A method using a cleaning blade is also one of them, in which an elastic body such as rubber is brought into direct contact with a photosensitive member to scrape off the residual toner. In this method, the cleaning blade is arranged so that the lower end of the blade abuts on a horizontal line extending from the center of the photosensitive drum on the side that rotates upward, or a portion located slightly above the horizontal line, and the photosensitive drum rotates. As a result, the residual toner is scraped off.

By the way, the cleaning blade is usually attached to a metal support by a double-sided adhesive tape or a hot melt adhesive, but the electric resistance value of the entire cleaning blade is governed by the electric resistance value originally possessed by the polymer composition. In this case, the electric resistance value of the cleaning blade shows a high resistance value of 10 ¹¹ Ω or more, and it is not possible to remove the triboelectrification of the photoconductor and it is continuously used for a long time. ,
The image may be adversely affected (white streaks, unevenness), or the toner may be scattered on the back surface of the cleaning blade.
The problem of so-called toner scattering occurs, and it is hard to say that it can be suitably used as a cleaning blade.

Therefore, in order to lower the electric resistance value of the cleaning blade, for example, as described in JP-A-57-48766, conductive carbon black is added to the composition to give a volume-specific property. A technique is known in which the resistance value is adjusted to 10 ⁴ Ω · cm or less and the blade is used as a static electricity removing blade. However, since the volume resistivity value is configured to be 10 ⁴ Ω · cm or less, electric charges existing other than the portion to be removed are also removed, and it is difficult to obtain a clear image. On the other hand, in order to adjust the electrical resistance value by blending conductive carbon black into the polymer in order to adjust the volume resistivity value of the cleaning blade to 10 ⁴ Ω · cm or more, the dispersed state of the conductive carbon black and a slight amount The electric resistance value is likely to fluctuate drastically due to the difference in the addition amount, and when shifting to a mass production system, it becomes extremely difficult to supply a sheet having a stable electric resistance value. Moreover, in mass production, since 300 to 500 kg of raw material is used at one time, there is a considerable risk in terms of cost.

As a method other than the above, for example, JP-A-60
-243688 discloses a technique of forming a conductive coating layer containing a fluorine-based polymer on the surface of a cleaning blade, and Japanese Patent Laid-Open No. 1-118112 discloses a technique of forming an antistatic layer. However, the former has a drawback that the cost becomes high and the frictional antistatic effect tends to disappear as the edge portion of the cleaning blade wears,
In addition, the latter has problems in workability and cost because it has a multi-layer structure, and there is still a problem that the adhesive strength with the support is drastically lowered depending on the antistatic material used.

Further, in Japanese Patent Application Laid-Open No. 63-65474, first, by combining a cleaning mechanism for removing static electricity and wiping the toner and a cleaning mechanism for mechanically scraping off the remaining toner, the triboelectric charging is performed. There is a technique to prevent this, but this technique requires two types of mechanism, a static elimination mechanism and a mechanism for mechanically scraping off, and there is a problem in terms of downsizing and cost of the device, and this method is not always sufficient. is not.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a simple structure,
An object of the present invention is to provide a cleaning blade that can freely control the electric resistance value between the support and the polyurethane sheet and has the electric resistance value according to each application.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to achieve the above-mentioned object, in which conduction between a support and a polyurethane sheet is achieved by a conductive composition applied between the two. It is a feature. That is, according to the present invention, in the cleaning blade arranged in the photoconductor cleaning section of the dry developing device, the conductive blade is adhered to the metal support by the double-sided adhesive tape or the adhesive. The cleaning blade is characterized in that the support and the conductive polyurethane sheet are electrically connected by a conductive composition.

[0010]

1 is a front view, FIG. 2 is a sectional view, and FIG. 3 is a bottom view showing a preferred structure of a cleaning blade of the present invention. Sheet, 3 is a double-sided adhesive tape, and 4 is a conductive composition. The support is for fixing and supporting the conductive polyurethane sheet, and is made of a metal material such as a steel plate or aluminum.
One type of galvanized steel sheet known as 20/20 (JIS G3313) is preferably used. In addition, SE
SECC of CCP20 / 20 indicates one type of galvanized steel sheet, P indicates that it has been treated with a phosphate, and 20/20 indicates that
Standard adhesion amount on top of stacked plates / Standard adhesion amount on bottom surface (g
/ M ² ) respectively.

The conductive polyurethane sheet is obtained by blending a thermoplastic resin polyurethane with a conductive material such as carbon black or an ion conductive material such as lithium perchlorate, for example, extrusion molding, injection molding or calender molding. Those molded by a molding method known per se are used. Further, in the case of a thermosetting resin, a mixture obtained by mainly mixing an ion conductive substance and then molded by a known molding method is used. As the physical properties of the sheet, those having a hardness (JIS A) of 70 to 100 ° and an electric resistance value (25 ° C.) at a pressing voltage of 50 V of 10 ³ Ω to 10 ¹⁰ Ω, preferably 10 ³ Ω to 10 ⁷ Ω The thickness of the sheet is not particularly limited, but a sheet having a thickness of about 1 to 3 mm is preferably used.

Any conductive composition can be used in the present invention as long as it can electrically connect the support and the conductive polyurethane and can be adhered to the two and is not peeled off. But it's okay. In particular,
Examples include conductive paints, conductive adhesives, and conductive sealants.

As the conductive coating material, a vehicle mainly composed of acrylic resin, urethane resin or epoxy resin and a solvent or compounding agent dispersed therein is used, and a conductive material such as carbon black, graphite or metal oxide is used. A dispersion of a filler, and a quaternary ammonium salt,
A mixture of an oligomer containing a salt such as a carboxylic acid salt or a sulfonic acid salt with the above paint is used, and its electric resistance value is 10 ⁴ to 10 ⁹ Ω, preferably 10 ⁴
Ω to 10 ⁷ Ω are used. The blending ratio of the conductive compounding agent varies depending on the type of compounding agent and the desired electric resistance value and cannot be specified unconditionally, but is usually 10 to 50% by weight with respect to the vehicle forming the conductive paint. A blending ratio of about this is preferable.

As the conductive adhesive, an acrylic resin,
A urethane resin, an epoxy resin, or a rubber polymer as a main component and the above-mentioned conductive compound mixed therein are preferably used. The amount of the conductive compound to be blended is preferably about 10 to 50% by weight, as in the case of the conductive paint.

As the conductive sealant, a material mainly containing an acrylic polymer, a urethane polymer, a silicone polymer or an epoxy resin and a mixture of the conductive compound is preferably used.

An important technical feature of the present invention is that the support and the conductive polyurethane sheet are electrically connected by a conductive composition. According to this method, the kind of conductive material in the conductive composition and By appropriately changing the blending ratio, the electric resistance value of the conductive composition can be changed,
This makes it possible to set the electric resistance value of the cleaning blade itself to an arbitrary value. Further, when a conductive adhesive is selected as the conductive composition, the support and the conductive polyurethane can be electrically connected to each other, and the both can be strongly adhered, which is very effective.

That is, according to the present invention, by preparing a conductive composition having a different electric resistance value, the electric resistance value of the cleaning blade can be changed to an arbitrary value without changing the conductive polyurethane sheet. Therefore, it is possible to prevent the change in the physical properties of the conductive polyurethane sheet due to the change in the electric resistance value, which has been a problem in the past. Explaining this point in more detail, the conductive polyurethane sheet has the following properties depending on the type of conductive material to be blended, as shown in Table 1 below.
Since the physical properties change greatly, there is a problem that the setting conditions for installing the cleaning blade change, and the present invention can eliminate such an instability requirement.

[0018]

As the double-sided adhesive tape for bonding the support and the conductive polyurethane sheet, commercially available double-sided adhesive tape is generally used.
A double-sided adhesive tape sold by Dainippon Ink and Chemicals, Inc. under the trade name of "# 8103D" is preferably used.
As the adhesive, a known adhesive can be used, but it is preferable to use a hot melt adhesive from the viewpoint of workability and the like.

The electric resistance value of the cleaning blade of the present invention is, as shown in FIG. 4, a current I at a potential difference V between the support and the two terminals 6a and 6b of the conductive polyurethane sheet.
The electric resistance value (R = V / I) when the current flows is expressed as a value measured by the electric resistance measuring device 5. As shown in FIG. 1, the support and the conductive polyurethane sheet are usually attached to each other in an overlapped state to form a cleaning blade as a whole. In this state, the support and the conductive polyurethane sheet are interrupted by a double-sided adhesive tape interposed between the two,
In the present invention, the conductive composition is applied to the bonding portion between the support and the conductive polyurethane sheet to achieve electrical continuity between them.

The conductive composition may be applied anywhere between the support and the conductive polyurethane sheet, and may be at the bonding end surface of the support and the conductive polyurethane sheet or at any other place, but the conduction is ensured. For this reason, the conductive polyurethane sheet may be formed so as to slightly overlap the upper surface thereof. With this configuration, the upper end of the conductive polyurethane sheet of the cleaning blade is configured as a free end, and the upper end surface is arranged in contact with the photoconductor drum so that the cleaning blade located above it removes it. Will be done.

As described above, by combining the conductive composition with a conductive polyurethane sheet having an electric resistance value of 10 ⁴ Ω or less, the electric resistance value of the cleaning blade itself can be made 10 ⁵ Ω or more. Therefore, the static electricity of the residual toner can be suitably removed, and a cleaning blade having an electric resistance value suitable for the application can be easily obtained.

[0023]

According to the present invention, an electric resistance value of 10 even if the electric charges other than the portion desired to be removed is removed as it is.
The electrical resistance value of the cleaning blade can be made 10 ⁴ Ω or more by electrically conducting a conductive polyurethane sheet of ⁴ Ω or less to the support with a conductive composition, whereby an arbitrary electrical resistance value can be obtained. It is possible to easily obtain the cleaning blade having the same without changing the conductive polyurethane sheet. Furthermore, since the conductive polyurethane sheet is not changed according to the target electric resistance value, it is possible to avoid the situation where the physical properties of the conductive polyurethane sheet change with the change of the electric resistance value.

[0024]

EXAMPLES The present invention will be described below with reference to examples. <Example 1> Thermoplastic resin polyurethane (Product name: P433
RNAT, manufactured by Nippon Miractolan Co., Ltd.) was mixed with 100 parts by weight of 20 parts by weight of conductive carbon black (trade name: Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 0.2 parts by weight of lithium perchlorate to give a thickness of 2. 0 mm, hardness (JIS A) 8
A sheet having an electric resistance value of 5.0 × 10 ³ Ω at 25 ° C. at 0 ° and a pressure voltage of 50 V was used as a conductive polyurethane sheet. On the other hand, an electrogalvanized steel plate (trade name: Bonde steel plate, manufactured by Nippon Steel Corporation) was used as the support. The conductive polyurethane sheet was attached to this support using a double-sided adhesive tape (# 8103D manufactured by Dainippon Ink and Chemicals, Inc.) as shown in FIGS. 1 to 3. In this state, the electric resistance value measured by the method shown in FIG. 4 was 3.0 × 10 ¹² Ω at 25 ° C. Next, a conductive paint was applied and dried between the support and the conductive polyurethane sheet as shown in FIG. 1 to electrically connect the support and the conductive polyurethane. When the electric resistance value of this blade was measured by the method of FIG. 4, it was 6.1 × 10 ⁵ at 25 ° C.
A cleaning blade of Ω was obtained. The electric resistance was measured by completely drying the conductive paint alone and found to be 5.3 × 10 ⁵ Ω at 25 ° C. The cleaning blade thus obtained is used as an organic photoconductor (OPC).
It was mounted on a copying machine equipped with a drum (φ = 80 mm), and a copy was obtained under the condition of a copying speed of 50 / min. When you get 100 copies, turn off the copier and
After a few minutes, the power was turned on again and 100 copies were made. Repeat this operation, and when the number of copies reaches 1000,
The state of the obtained image was observed by checking the toner contact with the photoconductor and the cleaning blade, the backing of the toner. As a result, no particular problem was observed even when the number of copies reached 10,000.

<Comparative Example 1> As the conductive polyurethane sheet, the same polyurethane sheet as in Example 1 was used and adhered to a support to obtain a cleaning blade. Using this blade, built in a copying machine in the same manner as in Example 1,
A copy operation was performed. As a result, the number of copies is 2000
Although no particular problem was observed up to the first sheet, when the number of copies reached the 5,000th sheet, toner scatter was observed in the obtained copy image, and the number of copies reached the 10,000th sheet. When this was done, the toner scatter on the copied image became even worse.

Example 2 As a conductive polyurethane sheet, 100 parts by weight of a polyurethane rubber (trade name: Adiprene C) crosslinkable with peroxide, 25 parts by weight of conductive carbon black, 0.1 part by weight of lithium perchlorate. Parts and a sheet obtained by blending 1.5 parts by weight of dicumyl peroxide were used in the same manner as in Example 1 to obtain a cleaning blade. This sheet had an electric resistance value of 3.0 × 10 ³ Ω at 25 ° C., a hardness of 72 ° and a sheet thickness of 1.8 mm. The electric resistance value of the cleaning blade before applying the conductive paint is 7.2 × 1 at 25 ° C.
It was 0 ¹¹ Ω. After applying and drying the conductive paint, the electric resistance value of the obtained cleaning blade is 5.7 at 25 ° C.
It was × 10 ⁵ Ω, and when this was attached to a copying machine,
Similar to Example 1, no particular problem was observed.

<Example 3> The same operation as in Example 2 was performed except that a conductive adhesive was used instead of the conductive paint. The electric resistance value of the obtained cleaning blade is 2
It was 2.1 × 10 ⁶ Ω at 5 ° C. When this was mounted on a copying machine, no particular problem was observed as in Examples 1 and 2. The conductive adhesive alone was completely dried and the electric resistance value was measured and found to be 2.6 × 10 ⁶ Ω at 25 ° C.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a cleaning blade of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a bottom view of the same.

FIG. 4 is a schematic diagram of an apparatus for measuring electrical resistance.

[Explanation of symbols]

 1 Support 2 Conductive Polyurethane Sheet 3 Double-Sided Adhesive Tape 4 Conductive Composition 5 Electrical Resistance Value Measuring Device 6a, 6b Terminal

Claims (2)

[Claims] 1. A cleaning blade disposed in a photosensitive member cleaning section of a dry developing device, wherein the conductive blade is adhered to a metal support through a double-sided adhesive tape or an adhesive. A cleaning blade, wherein the support and the conductive polyurethane sheet are electrically connected by a conductive composition. 2. The cleaning blade according to claim 1, wherein the conductive composition is a conductive paint, a conductive adhesive or a conductive sealant.