JP2001175095A - Transfer blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer blade which has a coating layer, is free of an image defect and the wear of a blade edge and makes the coating layer hardly peelable. SOLUTION: The coating layer is formed in at least the contact part of a blade body of the transfer blade with a mating member by using a composition of a fluororesin or silicone base resin, more preferably a compound of a fluorinated olefin resin, fluorine denatured acrylate resin and acrylate which is crosslinked by an isocyanate crosslinking agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer blade used as a transfer means for a toner image in an electrophotographic process utilizing a photoconductive phenomenon. The present invention relates to a device in which a coating layer is formed in the vicinity.

[0002]

2. Description of the Related Art As is well known, a continuous electrophotographic process is performed as shown in FIG. 1 in a type using a transfer belt, for example.

[0003] First, the surface of the rotating drum-shaped photosensitive member 2 is uniformly charged by the charger 1, and then the photosensitive member 2 is charged by the exposing device 3.
An electrostatic latent image corresponding to an image is formed by irradiating light to a portion other than the image portion on the surface to remove the electric charge. In the developing unit 4, a charged toner having a characteristic opposite to that of the electrostatic latent image adheres according to the pattern of the electrostatic latent image, and forms a visible image (toner image).

On the other hand, an endless transfer belt 5 circulates slightly below the photoreceptor 2, and a recording material (not shown) conveyed on the belt 5 at an appropriate timing is on the back side of the belt 5. Then, a charge having a characteristic opposite to the charge polarity of the toner is given through the transfer means 6 contacted from the toner. Therefore, when the toner image formed on the surface of the photoconductor 2 reaches the lower rotation position, the toner image is transferred onto the surface of a recording material such as recording paper that has been conveyed. Thereafter, the toner image is fixed by the fixing device 7,
Further, the surface of the photoreceptor 2 after the transfer is returned to the initial state by the action of the static eliminator 8 and the cleaner 9, and one cycle of the electrophotographic process is completed.

As a typical example of the transfer means 6 in such an electrophotographic process, as shown in FIG. 2, a transfer blade 10 having a blade body 10a supported by a support 10b is arranged as shown in FIG. It is used in a contact state. Conventionally, the blade body 10
a is made of a rubber material such as hydrin rubber, urethane rubber, nitrile rubber or the like, or a coating layer using a resin material is formed on the rubber blade body 10a.

[0006]

However, the resin material coated on the conventional blade needs to have flexibility and adhesion to prevent the rubber material from peeling off from the rubber blade body. Was difficult to use. For this reason, there has been a problem that a large force is required for driving the belt, and a problem that the amount of wear of an edge portion of the transfer blade in contact with the belt increases. Further, generally, the volume resistivity is as low as about 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω · cm, and discharge occurs from a coat layer other than the end cut surface (rubber exposed portion) of a necessary discharge portion, and the image Worsened.

Therefore, the present invention is to solve these problems in the conventional transfer blade.

The inventor of the present application uses various materials for the coating layer to improve the volume resistivity, reduce the friction coefficient,
In the process of trial and error in the adhesion to the rubber blade main body, it was experimentally determined that it is extremely effective to form a coating layer using a fluorine-based resin, a silicon-based resin, or a composition containing these. .

[0009]

Means for Solving the Problems (Structure of the First Invention) The structure of the first invention of the present application (the invention of claim 1) for solving the above-mentioned problems is the same as the structure of the toner image on the photosensitive member in the electrophotographic process. Is a transfer blade used to transfer an image onto a recording material, wherein a coating layer made of a fluorine-based resin, a silicon-based resin, or a composition containing these is formed on at least a contact portion of the transfer blade with a counterpart member. Is a transfer blade.

(Structure of the Second Invention) The structure of the second invention (the invention described in claim 2) for solving the above-mentioned problem is as follows.
The transfer blade according to the first aspect, wherein the coating layer uses a fluorinated olefin resin or a composition containing the same.

(Structure of Third Invention) The structure of the third invention of the present application (the invention according to claim 3) for solving the above problems is as follows.
A transfer blade, wherein the coating layer according to the second invention uses a compound of a fluorinated olefin resin, a fluorine-modified acrylate resin and an acrylate resin, or a composition containing the same.

(Structure of the Fourth Invention) The structure of the fourth invention of the present application (the invention according to claim 4) for solving the above problems is as follows.
The coating layer according to the third invention uses a fluorinated olefin resin, a mixture of a fluorine-modified acrylate resin and an acrylate resin, or a composition containing the same,
In addition, the transfer blade is one that is cross-linked by an isocyanate-based cross-linking agent.

(Structure of the Fifth Invention) The structure of the fifth invention (the invention described in claim 5) for solving the above problems is as follows.
The transfer blade according to any one of the first to fourth inventions, wherein the coating layer has a volume resistivity of 1 × 10 ¹⁰ Ω · cm or more.

[0014]

Operation and effect of the present invention (operation and effect of the first invention) A material made of a fluorine-based resin, a silicon-based resin or a composition containing these resins is used as the rubber material constituting the conventional transfer blade main body or the coating layer formation. Has a significantly higher volume resistivity and a lower coefficient of friction than the nylon-based resin material used in the above.

In the first aspect of the present invention, the coating layer made of a fluorine-based resin, a silicon-based resin, or a composition containing these is formed at least at the contact portion of the transfer blade with the counterpart member. Since the coefficient of friction is small, a large force is not required to drive the transfer belt or the transfer drum, which is the mating member, and there is no problem that the amount of wear at the edge of the transfer blade is increased.

(Function / Effect of the Second Invention) When the coating layer of the transfer blade is made of a fluorinated olefin resin or a composition containing the same as in the second invention, the effect of the first invention is obtained. Is particularly well exhibited.

(Function / Effect of the Third Invention) By forming the coating layer of the transfer blade with the material of the first invention or the second invention, it is possible to secure the above-mentioned effect due to the reduction of frictional resistance. It has been newly found that the adhesion between the coating layer and the blade body, which is usually made of rubber, is slightly reduced, and as a result, the transfer blade tends to be peeled off at the time of cutting. As exaggeratedly shown in FIG. 3, there is a concern that such peeling of the coating layer 10c from the blade main body 10a may hinder good contact of the transfer blade 10 with the belt 5 (or transfer drum).

However, as in the third invention, when a composition obtained by adding a fluorine-modified acrylate resin and an acrylate resin to a fluorinated olefin resin or a composition containing the same is used as a constituent material of the coating layer. It has been found that can improve the adhesion of the coating layer to the blade body while maintaining the effects of the first invention and the second invention, and can effectively prevent peeling of the both during cutting of the transfer blade.

(Function / Effect of the Fourth Invention) In the fourth invention, the coating layer uses a blend of a fluorinated olefin resin, a fluorine-modified acrylate resin and an acrylate resin or a composition containing the same, and ,
Since it is cross-linked by the isocyanate-based cross-linking agent, the adhesion of the coating layer to the blade body is further improved, and the peeling of the coating layer hardly occurs.

(Function and Effect of Fifth Invention) As in the fifth invention, the volume resistivity of the coating layer is 1 × 10 ¹⁰ Ω · cm.
As described above, it is possible to particularly favorably prevent an image defect due to the shortage of volume resistivity in the conventional technology. The constituent material of the coating layer according to the first to fourth inventions is generally 1 × 10 ¹⁰ Ω ·
Although the volume resistivity is not less than cm, the volume resistivity can be further improved by changing the fluorinated olefin polymer type or the mixing ratio of various fluorinated olefin polymers for these materials.

[0021]

Next, embodiments of the first to fifth inventions will be described. In the following, simply "the present invention"
When it says, it refers to 1st invention-5th invention collectively.

[Transfer Blade] The transfer blade according to the present invention is limited as long as it is a transfer conductive blade, that is, a blade used to transfer a toner image formed on a photosensitive member to a recording material in an electrophotographic process. There is no.

Although there is no particular limitation on the shape, configuration and usage of the transfer blade, a typical configuration example is shown in FIG. 4 as a side sectional view. That is, the transfer blade 11 includes a blade main body 11a and a support 11b, and a coating layer 11c made of a predetermined material is formed on a predetermined portion of the blade main body 11a.

[Blade Body] The constituent material of the blade body is not limited as long as it exhibits a necessary function and elasticity or flexibility as a transfer blade, but is typically made of rubber, and particularly, hydrin rubber, urethane rubber, and nitrile. A rubber material such as rubber is preferably used. In FIG. 4, the blade main body is shown as a side cross-section, but in a normal case, the blade main body has a cross-sectional shape shown in the drawing and is formed as a plate-like body that is elongated in the depth direction. The dimensions, such as the thickness of the blade body and the lengths in the vertical and depth directions in the figure, are not limited at all, and may be arbitrarily set as necessary. An edge on one side of the upper end in FIG. 4 is a contact portion with a partner member (transfer belt or transfer drum).

At the tip of the transfer blade, a tapered surface is formed in which one side of the blade (the surface including the edge in contact with the mating member) is cut obliquely, including a blade body and a coating layer described later. May be.

[Coating Layer] The coating layer is formed on at least the contact portion of the transfer blade (or the blade main body) with the counterpart member, preferably on the contact portion and the vicinity thereof. In the normal case, the transfer blade is inclined to the transfer belt or the transfer drum so as to cross the width direction (the depth direction in each drawing) and to one side as shown in FIGS. Contact.

The coating layer may be formed at least at the contact portion with the counterpart member or at the contact portion and the vicinity thereof. Therefore, only the surface to which the one edge portion of the blade body belongs is provided. In addition, it is sufficient if it is formed only on the tip side portion near the edge portion. However, even if a coating layer is formed on other portions of the blade main body, there is no particular problem. For example,
When a coating layer is formed by dipping the blade body into a coating solution, the coating layer is necessarily formed on both side surfaces of the blade body. The thickness of the coating layer can be arbitrarily set as necessary, and can be set, for example, to about 5 to 30 μm.

[Fluorine Resin, Silicon Resin] The constituent material of the coating layer in the present invention is a fluorine resin,
It is a silicone resin or a composition containing these. Here, the “composition” refers to a composition containing a fluorine-based resin or a silicon-based resin as a main component and other arbitrary components as long as the action and effect of the present invention are not impaired. As the “other optional component” mentioned here, for example, an epoxy resin, an acrylic resin, a polyester resin and the like can be preferably exemplified.

Particularly preferred as the fluorinated resin or a composition containing the same is a fluorinated olefin resin or a composition containing the same, and a fluorine-modified acrylate resin and an acrylate resin mixed with the fluorinated olefin resin. Or a composition containing them, a mixture of a fluorinated olefin resin and a fluorine-modified acrylate-based resin and an acrylate-based resin, or a composition containing these and further cross-linked by mixing an isocyanate-based crosslinking agent, And so on.

Of these, the technical meaning of using a fluorinated olefin resin is as described above, but by blending a fluorine-modified acrylate resin and an acrylate resin with this fluorinated olefin resin, And the adhesion to the film can be further improved. Further, by adding an isocyanate-based crosslinking agent, the adhesion of the coating layer to the blade body can be further improved, and in particular, the OH group of the acrylate resin can be effectively crosslinked as a crosslinking site. Is preferred.

The type of the silicon-based resin is not particularly limited. For example, a silicon-modified polyester resin, a silicon-modified acrylic resin, or the like can be preferably used.

[Fluorinated olefin resin] The fluorinated olefin resin is obtained by polymerizing or copolymerizing a fluorinated olefin monomer such as tetrafluoroethylene, vinylidene fluoride, hexafluoropropylene, and vinyl fluoride ether. For example, polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene A copolymer or the like can be preferably used.

[Fluorine-modified acrylate resin] The fluorine-modified acrylate resin is, for example, an acrylic resin, in which a perfluoroalkyl ester of acrylic acid or methacrylic acid or a partially fluorinated alkyl group is linked by an organic linking group. A polymer obtained by polymerizing a fluorinated acrylate or fluorinated methacrylate composed of an ester or the like having a modified structure with an acrylate or methacrylate not modified with fluorine can be preferably used.

[Acrylate Resin] Examples of the acrylate resin include alkyl esters of acrylic acid or methacrylic acid such as methyl, ethyl, butyl, octyl and dodecyl, and hydroxyalkyl esters such as hydroxyethyl and hydroxybutyl. And glycidyl esters and the like, and are usually homopolymers or copolymers of acrylate monomers, and particularly preferably homopolymers or copolymers of methyl methacrylate.

It is preferable that the acrylate resin has a plurality of OH groups in its molecule in relation to the addition of a crosslinking agent. For this purpose, for example, a hydroxyalkyl ester of acrylic acid or methacrylic acid is used as a monomer, a compound having an OH group is reacted with a reactive group in a polymer chain, or an OH group can be generated (or an OH group can be formed). OH groups can be generated (or unblocked) after the (blocked) monomer is polymerized.

[Crosslinking Agent] As the crosslinking agent, an isocyanate-based crosslinking agent, particularly a polyisocyanate compound having two or more functional groups is particularly preferably used. For example, 2,4- and 2,6-
Tolylene diisocyanate, ortho toluidine diisocyanate, naphthylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate and its modified carbon diimide, trimethylolpropane adduct of hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, polymeric polyisocyanate Etc. can be preferably used alone or in combination.

[0037]

EXAMPLE ( Preparation of Transfer Blade ) A transfer blade (transfer blade without a coating layer) having the conventional structure shown in FIG. 2 above, wherein the blade body is made of hydrin rubber and has a cross-sectional thickness of 2 μm. This was produced according to a conventional method, and this was designated as Comparative Example 1.

Next, the same blade body as in Comparative Example 1 was dipped using a coating solution of N-methoxymethylated nylon, which is a nylon resin material, and required cutting was performed after the coating solution was solidified. In addition, a transfer blade in which a coating layer having a thickness of about 15 μm was formed in the state shown in FIG.

On the other hand, as Example 1, a transfer blade having a coating layer of vinylidene fluoride-tetrafluoroethylene, which is a fluorinated olefin resin, was produced in the same manner as in Comparative Example 2.

In Example 2, a fluorinated olefin resin (specifically, vinylidene fluoride-tetrafluoroethylene) and a fluorine-modified acrylate resin (specifically, acrylic acid) were prepared in the same manner as in Comparative Example 2. Of a partially fluorinated alkyl ester and methyl methacrylate as a main component) and an acrylate resin (specifically, a methyl methacrylate resin obtained by copolymerizing hydroxyethyl methacrylate) in a weight ratio of 80:10. A transfer blade having a coating layer composed of the composition of No. 10 was prepared.

Further, in Example 3, a polyisocyanate crosslinking agent (specifically, a trimethylolpropane adduct of hexamethylene diisocyanate) was added to the same compound as in Example 2 in the same manner as in Comparative Example 2. 5 phr
A transfer blade having a coating layer formed of a blended and crosslinked material was produced.

( Physical Properties and Evaluation of Transfer Blade ) Comparative Example 2
For the transfer blades of Examples 1 to 3, the volume resistivity (Ω · cm) of the coating layer was measured. The results are shown in Table 1 at the end, and it can be seen that the volume resistivity of each example is higher than that of the comparative example.

Next, regarding the transfer blade of each of the above examples,
Their thickness is about 2mm.
A 2 × 2 mm sample piece 12 is cut out and a PET (polyethylene terephthalate) sheet 14
Was placed in a free state on a stack of. Then, the substrate 13 was gradually inclined, and the angle (θ) at which the sample piece 12 started to slide down from above the sheet 14 was measured. The results are shown in Table 1 at the end. In Comparative Example 1, the angle θ is very large, and in Comparative Example 2, the angle θ is slightly small, but is considerably larger than Examples 1-3. The magnitude of the angle θ is considered to correspond to the magnitude of the friction coefficient of the sample piece 12 (that is, the blade body).

Further, with respect to the transfer blades of Examples 1 to 3, the presence or absence of peeling between the blade body and the coating layer during the cutting process by the cutting blade after the formation of the coating layer (the coating layer Was observed visually. In addition, as the cutting process, there are a processing method (method A) with a cutting speed of 0.5 mm / sec., In which peeling is unlikely to occur, and a processing method with a cutting speed of 2 mm / sec. An example was performed. Comparative Example 1,
2 was not evaluated as not applicable.

The results of the above evaluations were evaluated as follows: the case where peeling occurred in both methods A and B was evaluated as x, the case where peeling occurred only in the case of method B was Δ, and the peeling occurred in both methods A and B An example in which no occurrence was observed is shown in Table 1 as ○, and it was found that the adhesion of the coating layer was increased in the order of Example 1 → Example 2 → Example 3.

[0046]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a diagram conceptually illustrating an example of an electrophotographic process.

FIG. 2 is a diagram showing a conventional transfer blade and its use state.

FIG. 3 is a view showing a peeled state of a coating layer.

FIG. 4 is a diagram illustrating a configuration of a transfer blade having a coating layer.

FIG. 5 is a diagram showing a method for testing the frictional resistance of a transfer blade.

[Explanation of symbols]

 5 transfer belt 10, 11 transfer blade 11a blade body 11c coating layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirofumi Okuda 3-1, Higashi 3-chome, Komaki City, Aichi Prefecture (72) Inventor Kenichi Tsuchiya 3-1-1, Higashi 3-chome, Komaki City, Aichi Prefecture Tokai Rubber Industry Co., Ltd. F term (reference) 2H032 AA05 4F006 AA31 AB13 AB19 AB24 AB39 AB65 BA07 BA09 CA08

Claims (5)

[Claims] 1. A transfer blade used for transferring a toner image on a photosensitive member onto a recording material in an electrophotographic process, wherein at least a contact portion of the transfer blade with a counterpart member is made of a fluororesin or silicon. A transfer blade comprising a coating layer formed using a base resin or a composition containing the same. 2. The transfer blade according to claim 1, wherein the coating layer is made of a fluorinated olefin resin or a composition containing the same. 3. The coating layer according to claim 2, wherein the coating layer is a mixture of a fluorinated olefin resin, a fluorine-modified acrylate resin and an acrylate resin, or a composition containing the same. Transfer blade. 4. The coating layer is made of a mixture of a fluorinated olefin resin, a fluorine-modified acrylate resin and an acrylate resin or a composition containing the same.
4. The transfer blade according to claim 3, wherein the transfer blade is cross-linked by an isocyanate-based cross-linking agent. 5. The coating layer having a volume resistivity of 1
2. The method according to claim 1, wherein the resistance is not less than × 10 ¹⁰ Ω · cm.
The transfer blade according to claim 4.