JP2012048126A - Transfer roller for liquid development electrophotographic device and manufacturing method of transfer roller for liquid development electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid development electrophotographic device excellent in printing accuracy even when a resin film is a matter to be printed.SOLUTION: A transfer roller for a liquid development electrophotographic device where an outer surface contacting with a photoreceptor is formed of a polyurethane elastic body is characterized in that a matter to be printed to which an image of the photoreceptor is transferred is a resin film, and that the outer surface is formed of a polyurethane elastic body obtained by reaction of polyester polyol with bifunctional isocyanate and is subjected to hardening treatment with isocyanate.

Description

  The present invention relates to a transfer roller for a liquid development electrophotographic apparatus, and more particularly to a transfer roller for a liquid development electrophotographic apparatus in which an outer peripheral surface in contact with a photoreceptor is formed of a polyurethane elastic body.

2. Description of the Related Art Conventionally, an electrophotographic apparatus has been widely used in which an electrostatic latent image drawn on a photoreceptor with a laser or the like is visualized with toner and transferred to a surface of paper or the like for printing.
In recent years, the toner particles have been refined to improve printing accuracy, and have been refined to a liquid called a carrier such as liquid paraffin, silicone oil, mineral oil, or vegetable oil, for example, to about 1 μm. A liquid developer (also referred to as a liquid toner) in which toner particles are dispersed has been used.
In recent years, various studies on a liquid developing electrophotographic apparatus using the liquid toner have been conducted. In Patent Document 1 below, an elastic body layer made of a polyurethane elastic body is provided on the outer periphery of a shaft body such as a core metal. It is described that various rollers for a liquid developing electrophotographic apparatus are formed.

By the way, the liquid developing electrophotographic apparatus is provided with a transfer roller for transferring an image from a photosensitive member to a printing material such as printing paper, and the transfer roller is exposed to light with an appropriate nip width through the printing paper. The liquid developing electrophotographic apparatus is arranged so as to be rotated according to the movement of the printing paper while being in contact with the body.
If this transfer roller slips between its outer peripheral surface and the back side of the printing paper during printing, the image on the photoreceptor may not be faithfully transferred to the printing paper, and high print quality may not be ensured. Have
On the other hand, if the tackiness is excessively imparted to the transfer roller, the printing paper that has passed between the transfer roller and the photoconductor may be wound around the transfer roller without being peeled off from the transfer roller.
Therefore, conventionally, a transfer roller for a liquid developing electrophotographic apparatus has been required to adjust not only the properties relating to its elasticity but also the surface tackiness and slipperiness to a certain extent.

JP 2008-8982 A

In recent years, due to diversification of needs, it has become necessary to print not only printing paper but also resin films and the like, for example, a shrink film that can be covered to give a decorative property to a beverage PET bottle. On the other hand, there is a demand for printing with high accuracy using a liquid developing electrophotographic apparatus.
However, until now, there has been almost no investigation regarding the use of a printed material as a resin film. For example, in terms of tackiness and slipperiness between polyurethane elastic bodies, resin films and paper have different characteristics. From the above, it is difficult to divert the transfer roller of the liquid developing electrophotographic apparatus that used paper as a printing material to the liquid developing electrophotographic apparatus that uses a resin film as the printing material.
That is, there is a problem that it is difficult to provide a liquid developing electrophotographic apparatus having excellent printing accuracy while using a resin film as a substrate.

As a result of intensive studies to solve the above problems, the present inventors have found that a unique phenomenon is usually generated with respect to the tack force between the resin film and the polyurethane elastic body.
That is, when a transfer roller that has not been subjected to any treatment on the outer peripheral surface is used as it is in printing of a resin film, the resin film that has passed between the transfer roller for a liquid developing electrophotographic apparatus and the photoreceptor adheres to the transfer roller. It has been found that the phenomenon of peeling from the surface of the transfer roller after a certain amount of time in the state of being pulled in the rotational direction occurs repeatedly, causing pulsation in the tension applied to the resin film and lowering the print quality.

  In addition, as a means for adjusting the tack property of the transfer roller for the liquid developing electrophotographic apparatus to a state suitable for the resin film, the present inventors apply a resin having a low tack property to the surface of the transfer roller for the liquid developing electrophotographic apparatus. As a result of studying a method of coating to suppress the adhesion of the resin film to the transfer roller for the coating liquid developing electrophotographic apparatus, such a method improves the surface slipperiness, resulting in slippage between the resin film and the resin film. I found out that

  A transfer roller for a liquid developing electrophotographic apparatus having a balance between tackiness and slipperiness is obtained by forming an outer peripheral surface in contact with the photoreceptor with a predetermined polyurethane elastic body and curing the outer peripheral surface with isocyanate. And the present invention has been completed.

  That is, the present invention relating to a transfer roller for a liquid developing electrophotographic apparatus is a transfer roller for a liquid developing electrophotographic apparatus in which an outer peripheral surface in contact with the photoreceptor is formed of a polyurethane elastic body, and transfers an image on the photoreceptor. The printed material to be printed is a resin film, and the outer peripheral surface is formed of a polyurethane elastic body obtained by reacting a polyester polyol and a bifunctional isocyanate, and is cured by isocyanate.

  According to the present invention, since a transfer roller for a liquid developing electrophotographic apparatus having a good balance between tackiness and slipperiness with a resin film can be obtained, a liquid excellent in printing accuracy while using a resin film as a substrate. A developing electrophotographic apparatus can be provided.

1 is a schematic diagram schematically showing one usage pattern of a liquid developing electrophotographic apparatus. The perspective view which shows the transfer roller for liquid development electrophotographic apparatuses of 1 aspect. Schematic which showed a mode that printing was performed on the resin film using the transfer roller for conventional liquid development electrophotographic apparatuses.

Hereinafter, preferred embodiments of the present invention will be described (based on the accompanying drawings).
First, a usage mode of the transfer roller for a liquid developing electrophotographic apparatus in the present embodiment will be described with reference to FIGS.

FIG. 1 schematically shows a printing line in which a liquid developing electrophotographic apparatus provided with a transfer roller for liquid developing electrophotographic apparatus according to the present embodiment (hereinafter also simply referred to as “transfer roller”) is used. Yes, reference numeral 1 represents a liquid developing electrophotographic apparatus.
Reference numeral 2 represents a transfer roller, and FIG. 2 is a perspective view of the transfer roller 2.
Further, reference numeral 3 in FIG. 1 represents a photoconductor, and reference numeral A represents a resin film that is a printing object.
Normally, in liquid development electrophotographic apparatuses, members such as a developing roller, a roller for picking up toner, a squeeze roller, and a polishing roller, and a member such as a cleaning blade are arranged around the photoconductor. Omitted and not shown.

  In the printing line shown in FIG. 1, a resin film A is continuously supplied to a liquid developing electrophotographic apparatus 1 from a film roll formed by winding a long belt-shaped resin film A. The liquid developing electrophotographic apparatus 1 In order to carry out continuous printing by the above-described method, a feeding machine 4 for feeding out the resin film A from the outside of the film roll and supplying it to the liquid developing electrophotographic apparatus, and a winding for winding up the resin film A after printing. A take-up machine 5 is provided.

  Accordingly, the resin film A is transported by a so-called roll-to-roll from a film roll mounted on the delivery device 4 to the winding roll of the winder 5 through the liquid developing electrophotographic apparatus 1, during which liquid developing electrophotography is performed. Printing is performed by the apparatus 1.

The resin film A passes between the photosensitive member 3 and the transfer roller 2 in the liquid developing electrophotographic apparatus 1, and further passes in a state of being pressed against the outer peripheral surface of the photosensitive member 3 by the pressure from the transfer roller 2. To do.
At this time, the toner adhering to the outer peripheral surface of the photoreceptor 3 is transferred to the surface of the resin film A, and the image is transferred.

As shown in FIG. 2, the transfer roller 2 has an elastic body layer 22 provided in an elongated cylindrical shape on the outer periphery of the core metal 21, and the elastic body layer 22 provided on the outer periphery of the roller is made of polyurethane elastic body. Is formed.
The transfer roller 2 is configured so that the outer peripheral surface of the elastic body layer 22 is in contact with the outer peripheral surface of the photoconductor 3 with an appropriate nip width, and the rotational axis of the photoconductor 3 and the core metal 21 are parallel to each other. 3 is provided in the liquid developing electrophotographic apparatus 1 so as to rotate according to the movement of the resin film A when printing on the resin film A.
If the elastic layer is formed of a polyurethane elastic body in the transfer roller for a liquid development electrophotographic apparatus, the thickness is generally 2 mm to 10 mm, and the nip width is 1 mm to 5 mm. The

  In order to prevent these, since there exists a possibility of producing a slip between the outer peripheral surface 22a of this elastic body layer 22 and the back surface of the resin film A, or generating an excessive tack, there exists a possibility that print quality may fall. It is important that the elastic body layer 22 is formed of a polyurethane elastic body obtained by reacting a polyester polyol and a bifunctional isocyanate, and the outer peripheral surface 22a of the elastic body layer 22 is cured with isocyanate. It is important that

  Among the components constituting the polyurethane elastic body, the polyester polyol is not particularly limited, but it is possible to prevent the elastic body layer 22 from changing characteristics due to the carrier constituting the liquid toner. In the method, it is preferable to use a polyester polyol obtained by reacting adipic acid, a bifunctional glycol and trimethylolpropane.

This will be described in more detail. In the liquid developing electrophotographic apparatus, the elastic bodies of various rollers may be slightly swollen by the carrier.
When such a swelling of the elastic layer occurs in the transfer roller, there is a possibility that the contact state with the photoreceptor is changed by changing the hardness or modulus or changing the outer diameter, thereby reducing the printing accuracy.
In the transfer roller 2 of the present embodiment, by using adipic acid as a raw material component of the polyester polyol, the volume change of the elastic body layer 22 due to the carrier is compared with the case where other dicarboxylic acids such as sebacic acid are used. Can be reduced, and a decrease in printing accuracy of the liquid developing electrophotographic apparatus 1 can be suppressed.

For the same reason, the bifunctional glycol preferably has 2 to 6 carbon atoms. Diethylene glycol, 1,4-butanediol, or 3-methylpentanediol (3-methyl-1,5- Pentanediol) is preferred.
When the bifunctional glycol has 2 to 6 carbon atoms, particularly diethylene glycol, 1,4-butanediol, or 3-methylpentanediol, the volume change of the elastic body layer 22 by the carrier is changed. It can be made small, and the fall of the printing precision of the liquid development electrophotographic apparatus 1 can be further suppressed.

Further, when the bifunctional glycol has a hydrophobic group such as 3-methylpentanediol, the elastic body layer 22 can be made to be hardly affected by temperature and humidity.
That is, the dimensional change between the low temperature and low humidity state and the high temperature and high humidity state is suppressed, and the change in printing accuracy due to the installation environment of the liquid developing electrophotographic apparatus 1 can be suppressed, and uniform printing can be performed. obtain.

The polyester polyol containing such raw material components is not particularly limited, but the number average molecular weight is preferably 500 to 3000, and more preferably 1000 to 3000.
The number average molecular weight of the polyester polyol is preferably in the above range because the polyester polyol having a number average molecular weight of more than 3000 has a viscosity that is too high and the workability in casting and other processes may be reduced. On the other hand, if it is less than 500, it may be difficult to obtain a cured product having low hardness.
The number average molecular weight can be measured using a gel permeation chromatograph (GPC). For example, using GPC manufactured by Tosoh Corporation: model name “HLC-8020”, columns “G-4000”, “ G-3000 "and" G-2000 "(both manufactured by Tosoh Corporation) can be linked together and measured using chloroform as the mobile phase.

In addition, the polyester polyol including such raw material components preferably has an average functional group number of 3.0 or more.
By using a polyester polyol having an average functional group number of 3.0 or more, an elastic body layer having a small compression set can be formed. For example, the compression set is less than 1% at 70 ° C. × 22 hours. An elastic layer may be formed.
Moreover, by increasing the average number of functional groups, chemical crosslinking can be increased and apparent physical crosslinking can be decreased, so that water absorption can be improved (reduction of water absorption).

The polyester polyol containing such raw material components preferably has an acid value of 0.2 to 1.0.
By reducing the acid value, water absorption can be improved (reduction of water absorption), and the dimensional change of the elastic body layer 22 due to temperature and humidity can be suppressed.

The bifunctional isocyanate constituting the polyurethane elastic body with such a polyester polyol is not particularly limited, and any of tolylene diisocyanate (TDI), xylene diisocyanate (XDI) or diphenylmethane diisocyanate (MDI) is used. In particular, either tolylene diisocyanate or xylene diisocyanate is preferable.
By using tolylene diisocyanate or xylene diisocyanate as the bifunctional isocyanate, it is possible to reduce the volume change of the elastic body layer 22 by the carrier, and to further suppress the decrease in the printing accuracy of the liquid developing electrophotographic apparatus 1.
Moreover, by using tolylene diisocyanate or xylene diisocyanate, the curing reaction with the polyester polyol can be carried out at a higher reaction rate than when diphenylmethane diisocyanate is used.
Therefore, the transfer roller 2 can be efficiently manufactured by using tolylene diisocyanate or xylene diisocyanate.

The compounding quantity of these polyester polyols and bifunctional glycol can be adjusted suitably, and can be mix | blended in the quantity which can be made into the hardening state which can be substantially used as a transfer roller.
In terms of being able to form an appropriate nip width by pressure contact with the photoreceptor 3, it is preferable to blend polyester polyol and bifunctional glycol so that the JIS-A hardness is 30 to 60 degrees, for example.
That is, a polyester polyol obtained by reacting adipic acid, a bifunctional glycol, and trimethylolpropane and tolylene diisocyanate or xylene diisocyanate are blended so that the hardness after curing is 30 to 60 degrees (JIS-A hardness). By forming the elastic body layer 22, it is possible to form an elastic body layer that is hardly affected by the carrier.

Further, it is preferable to adjust the polyurethane elastic body so that the volume resistivity of the elastic body layer 22 is 1 × 10 ² Ω · cm to 1 × 10 ⁶ Ω · cm by adding carbon black.
The carbon black to be used is not particularly limited. In addition to “Ketjen Black” commercially available from Ketjen Black International, “VULCAN” from CABOT, etc., highly conductive carbon black generally called acetylene black is used. First, carbon black generally referred to as furnace black, channel black, thermal black or the like can be used.
The volume resistivity of the elastic layer 22 is adjusted to 1 × 10 ² Ω · cm to 1 × 10 ⁶ Ω · cm by blending graphite with polyurethane elastic instead of part or all of this carbon black. May be.

As described above, isocyanate is used in the curing treatment for the outer peripheral surface 22a of the elastic layer 22 formed of such a polyurethane elastic body.
The isocyanate may be monofunctional or polyfunctional. For example, the bifunctional isocyanate exemplified as the component for forming the polyurethane elastic body can be used, and among them, diphenylmethane diisocyanate (MDI) can be used. preferable.
As this curing treatment, for example, a method in which an elastic body layer 22 formed of the polyurethane elastic body around the core metal 21 is immersed in a solution containing an isocyanate and an organic solvent can be employed.

This curing treatment is preferably performed to such an extent that the hardness of the elastic body layer 22 does not change greatly before and after the treatment, and the hardness of the elastic body layer 22 after the curing treatment is 30 to 60 degrees (JIS-A hardness). And it is preferable to implement so that the tack force with respect to the said resin film A of the outer peripheral surface 22a of the elastic body layer 22 may be 100 gf or more and 150 gf or less.
Moreover, as a surface property of the elastic body layer 22 after a hardening process, it is preferable that 10 point average roughness (JISB0601: Rzjis) is 7 micrometers or less.

  The core metal 21 for constituting the transfer roller 2 is not particularly limited. For example, the core metal 21 is made of a metal such as copper, iron, aluminum, nickel, or an alloy thereof. In addition, those plated by means such as hot dipping, electrolytic plating, and electroless plating can be used.

Next, a method for manufacturing such a transfer roller 2 will be described.
The transfer roller 2 according to the present embodiment can be manufactured by forming it into a predetermined shape by a so-called casting method and then adjusting the outer shape to perform the curing treatment.
More specifically, for example, a polyester polyol for setting a cored bar in a mold having a cylindrical cavity slightly larger in diameter than a transfer roller to be manufactured, and forming the elastic layer on the mold; A mixture of bifunctional isocyanate is injected, polyester polyol and bifunctional isocyanate are reacted and cured, then demolded, and the outer peripheral surface of the polyurethane elastic body that is cured in a cylindrical shape around the core metal is polished. A method of adjusting the dimensions required for the elastic layer to form the transfer roller can be employed.

And as a method of performing the curing treatment with isocyanate on the elastic body layer formed around the core metal, a method of bringing a liquid containing isocyanate into contact with the outer peripheral surface of the elastic body layer can be usually adopted. .
More specifically, a methyl ethyl ketone solution containing 1 to 10% by mass of diphenylmethane diisocyanate is prepared, and the transfer roller is immersed in this solution for several hours to several tens of hours to react the diphenylmethane diisocyanate with the polyurethane elastic body. -A curing method can be employed.
In addition, the said diphenylmethane diisocyanate is excellent in the point which can implement such hardening processing at normal temperature.

This will be explained more specifically. When heat is applied in the curing process, the elastic layer is distorted, and there is a possibility of causing a slight change in the outer diameter or the like.
In other words, the dimension adjusted by polishing is maintained as it is by performing the curing process at room temperature.
The term “normal temperature” as used herein means a temperature of 18 ° C. to 28 ° C., and the curing treatment is performed at 21 ° C. to 25 ° C. It is preferable to carry out at this temperature.

In place of such a method of immersing the transfer roller, for example, a fibrous sheet such as a fabric is impregnated with a solution containing an isocyanate and an organic solvent, and the sheet is wound around the outer periphery of the transfer roller to contain the isocyanate. It is also possible to bring the solution into contact with the outer peripheral surface of the elastic layer.
Furthermore, it is also possible to perform a curing process in which a solution containing an isocyanate is made into a mist shape or a shower shape and sprayed onto the outer peripheral surface of the transfer roller so as to come into contact with the outer peripheral surface of the elastic layer.

Thus, the transfer roller 2 can be brought into a state suitable for printing of the resin film A by curing the outer peripheral surface.
This will be described more specifically with reference to FIG.
FIG. 3 is a schematic view showing a state in which printing is performed on a resin film using a conventional transfer roller, where 2x represents a transfer roller and 3x represents a photoreceptor.
Ax represents a resin film.

As shown in this figure, when an excessive tack force is generated between the transfer roller 2x and the back surface of the resin film Ax, the resin film Ax passes between the transfer roller 2x and the photoreceptor 3x and is released from the nip. After that, it adheres to the outer peripheral surface of the transfer roller 2x and is bent downward.
Then, as indicated by the broken line in the figure, after the resin film Ax adheres with a certain width (D in the figure) in the circumferential direction of the transfer roller 2x, when the transfer roller 2x further tries to rotate, the resin film The peeling force T1 exceeding the tack force between the resin film Ax and the transfer roller 2x acts on the interface between Ax and the transfer roller 2x, and the resin film Ax is peeled off from the outer peripheral surface of the transfer roller 2x at a stretch.
In the conventional transfer roller 2x, such a phenomenon occurs repeatedly in a short period of time, and there is a possibility that fine vibrations may occur in the resin film Ax that has passed between the transfer roller 2x and the photoreceptor 3x.
This vibration also propagates to the resin film Ax in the nip, resulting in a decrease in print quality.
In order to prevent this, if a resin coating or the like is applied to the surface of the transfer roller, slippage is likely to occur between the transfer film and the resin film Ax, although it is possible to suppress a decrease in print quality due to vibration.

In this regard, the transfer roller 2 according to the present embodiment can reduce the tackiness of the outer peripheral surface without excessively affecting the frictional force with the resin film A.
That is, the transfer roller 2 according to this embodiment can adjust the surface state in a region from a state in which the polyurethane elastic body is not subjected to any surface treatment to a region that can be adjusted by resin coating. In addition, it is suitable for printing of a resin film in which strict requirements for tackiness and slipperiness are made.
Therefore, the transfer roller 2 of the present embodiment is not applicable only when the substrate to be printed is the resin film A, and paper, fabric, etc., which require less tackiness and slipperiness than the resin film. The present invention can also be applied to a liquid developing electrophotographic apparatus which is a target for printing the above-mentioned printed material, and this type of liquid developing electrophotographic apparatus can also exhibit the above-described effects.

  In the present embodiment, the type of the resin film A to be used is not particularly limited, and a polyethylene resin film, a polypropylene resin film, a polystyrene resin film, a polyethylene terephthalate resin film, a polyethylene naphthalate resin film, a polyamide resin film, A general resin film such as a polyimide resin film, a polyvinyl chloride resin film, or a fluororesin film can be used.

The resin film A may be a stretched product or an unstretched product, and in the case of a stretched product, it may be a uniaxially stretched product or a biaxially stretched product.
Furthermore, a laminate film in which a plurality of the resin films or the resin film and another film are laminated may be used.
For example, an aluminum vapor-deposited resin film can be used.
As such a resin film, the thing of about 10 micrometers-about 100 micrometers is employable normally.

In addition, in the transfer roller which has not been specially treated, it is difficult to adjust the slip and the tack property, and the resin film A is used in that the transfer roller 2 of the present invention can exert its effect more remarkably. A polyimide resin film is desirable.
Polyimide resin films are excellent in heat resistance and electrical insulation, and are often used in high-grade products such as base materials for flexible printed circuit boards. High-precision printing using liquid development electrophotographic devices Therefore, it can be said that it is a member suitable as a substrate to be printed using the transfer roller of the present invention.

For example, in recent years, a flexible printed wiring board (FPC) has a pitch between circuits approaching to several tens of μm, and a narrow pitch wiring is made to a region difficult to form by a general etching technique. Yes.
On the other hand, since the liquid developing electrophotographic apparatus is extremely excellent in printing accuracy, for example, an etching resist is printed with a liquid developing electrophotographic apparatus on an FPC raw material in which a copper foil is laminated on a polyimide resin film. As a result, it is possible to obtain an excellent product without short circuit or open circuit.
In addition, for example, by forming a circuit by printing on a polyimide resin film using toner containing conductive powder, it is possible to form a narrow pitch wiring that is difficult to form by an etching technique.
It should be noted that in the latter build-up type circuit formation, it is a clean and environmentally friendly method without performing waste liquid treatment or the like compared to the case where the circuit is formed by etching as in the former case. .

  In addition to the case of using the liquid developing electrophotographic apparatus in this way, according to the present invention, a liquid developing electrophotographic apparatus having excellent printing accuracy while using a resin film as a printing material in various methods of use. Can be provided.

EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.
Example 1
A polyurethane elastic body having the composition shown in “No. 1” in Table 1 was produced.
At this time, first, polyester polyol (trade name “Kuraray polyol F3010” manufactured by Kuraray Co., Ltd., reaction product of adipic acid, 3-methylpentanediol and trimethylolpropane, hydroxyl value = 85.5 mgKOH) and carbon black (Mitsubishi Chemical) A trade name “Diamond Black # 5”) and artificial graphite (manufactured by Nippon Graphite Co., Ltd., trade name “Fine Powder SGL-3”) were dispersed with three rolls to prepare an admixture.
Next, an isocyanate (mixed product of Sumika Bayer Urethane Co., Ltd., 2,4-toluene diisocyanate (A), 2,6-toluene diisocyanate (B) (mixing ratio A: B = 80: 20) was added to the obtained mixture. ) Were mixed and stirred to prepare a liquid as a raw material for the polyurethane elastic body.
This liquid is poured into a mold set with a pre-bonded SUS shaft (surface subjected to electroless nickel plating), reacted and cured at a temperature of 170 ° C. × 90 minutes, and around the core metal An elastic body layer was formed of a polyurethane elastic body.
Thereafter, the mold was removed from the mold, post-crosslinking was performed at 170 ° C. for 120 minutes, and the surface was polished to prepare a transfer roller having an outer diameter of 50 mm and a thickness of 3 mm.
This transfer roller was immersed in a methyl ethyl ketone solution containing 5% by mass of diphenylmethane diisocyanate, left in an environment of 23 ° C. and 50% relative humidity for 24 hours, and subjected to a curing treatment on the outer peripheral surface to produce a transfer roller of Example 1.
The hardness of the elastic layer did not change before and after this curing treatment, and both were 50 degrees.
Further, when the surface roughness of the elastic body layer after the curing treatment was measured, the 10-point average roughness (JIS B 0601: Rzjis) was 4.7 μm.

Separately, a test piece with a thickness of 3 mm having the same composition as the elastic layer was produced.
The test piece was prepared by performing surface polishing in the same manner as the transfer roller, and the 10-point average roughness (JIS B 0601: Rzjis) was 5.9 μm.

The transfer roller of Example 1 and an aluminum drum simulating a photoreceptor are set so that the nip width between the transfer roller and the aluminum drum is 3 mm, and a 25 μm-thick polyimide resin film ( Toray DuPont, trade name “Kapton H”).
In that case, the tendency for this polyimide resin film to wind around a transfer roller was not seen, but it was a good passing situation.

In addition, the tack force with respect to a polyimide resin film using the said test piece was measured as follows using the tack tester (brand name "PICMA tack tester II") by Imoto Seisakusho.
A polyimide resin film (Kapton H) is wound around the outer periphery of a cylindrical jig having a diameter of 50 mm and a width of 14 mm, and lowered at a speed of 300 mm / min toward the surface of the test piece fixed in the horizontal direction below the jig. The stress measured when the load of 500 g was applied for 10 seconds and then increased at a speed of 300 mm / min was measured as the tack force.
The tack force of this test piece was 110 gf.
In addition, when the same measurement was implemented using the test piece which has not been hardened, it was found that the tack force was 160 gf.

(Comparative Example 1)
A transfer roller was produced in the same manner as in Example 1 except that the curing treatment was not performed.
That is, the transfer roller was manufactured in a state where the surface tack force was 160 gf.
When the passage test of the polyimide resin film was conducted on the obtained transfer roller in the same manner as in Example 1, the polyimide resin film tends to wind around the transfer roller after passing between the aluminum drum and the transfer roller. It was seen.

  From this result, it was found that a tack force of 100 gf to 150 gf is suitable for the polyimide resin film.

(Example 2)
Evaluation was performed in the same manner as in Example 1 except that the blend of the polyurethane elastic body was changed to the blend of “No. 2” shown in Table 1.
As a result, it was found that a good transfer roller without winding was obtained even in a pass test of the polyimide resin film.
In Example 2 as well, when the tack force on the outer peripheral surface of the transfer roller before and after the curing process was measured using a test piece, it was found that after the curing process was 130 gf and before the curing process was 205 gf.

(Comparative Example 2)
A transfer roller was produced in the same manner as in Example 2 except that the curing treatment was not performed.
When the passing test of the polyimide resin film was carried out on the obtained transfer roller in the same manner as in Example 2, the polyimide resin film tends to wind around the transfer roller after passing between the aluminum drum and the transfer roller. It was seen.

Table 2 shows the characteristics of the transfer rollers of these examples and comparative examples.
Table 3 shows the results of further characteristic evaluation on the test pieces.

  The roller resistance values in Table 2 are as follows: a load of 500 g is suspended at both ends of the roller and left on the SUS plate, and the core metal and the SUS plate at the roller end are made of a high resistivity meter (product of ADC Corporation). Name “R8340A”), forming a circuit through the elastic layer using the cored bar and SUS plate as an electrode, applying a constant voltage of 100 V, and reading the resistance value (Ω) after 60 seconds It is.

  The volume resistivity was measured by using a resistivity meter manufactured by Mitsubishi Chemical Analytech Co., Ltd., trade name “HIRESTA UP”, and a URS probe attached to the apparatus.

  1: liquid development electrophotographic apparatus, 2: transfer roller, 3: photoconductor, 22: elastic body layer (polyurethane elastic body), 22a: outer peripheral surface (of elastic body layer)

Claims (12)

A transfer roller for a liquid developing electrophotographic apparatus in which an outer peripheral surface in contact with a photoreceptor is formed of a polyurethane elastic body,
The printed material to which the image of the photoreceptor is transferred is a resin film, and the outer peripheral surface is formed of a polyurethane elastic body obtained by reacting a polyester polyol and a bifunctional isocyanate, and is cured by isocyanate. A transfer roller for a liquid developing electrophotographic apparatus.   The transfer roller for a liquid developing electrophotographic apparatus according to claim 1, wherein the printing material is a polyimide resin film.   The transfer roller for a liquid developing electrophotographic apparatus according to claim 2, wherein the polyurethane elastic body has a JIS-A hardness of 30 to 60 degrees and a tack force of the outer peripheral surface with respect to the polyimide resin film is 100 to 150 gf. .   The transfer roller for a liquid developing electrophotographic apparatus according to any one of claims 1 to 3, wherein the isocyanate used in the curing treatment is diphenylmethane diisocyanate.   The transfer roller for a liquid developing electrophotographic apparatus according to claim 1, wherein the bifunctional isocyanate is either tolylene diisocyanate or xylene diisocyanate.   The transfer roller for a liquid developing electrophotographic apparatus according to claim 1, wherein the polyester polyol is obtained by reacting adipic acid, a bifunctional glycol, and trimethylolpropane.   The transfer roller for a liquid developing electrophotographic apparatus according to claim 6, wherein the bifunctional glycol is any one of diethylene glycol, 1,4-butanediol, and 3-methylpentanediol.   The transfer roller for a liquid developing electrophotographic apparatus according to claim 7, wherein the bifunctional glycol is 3-methylpentanediol. The liquid development electrophotography according to any one of claims 1 to 8, wherein the polyurethane elastic body contains carbon black, and the volume resistivity of the polyurethane elastic body is 10 ² to 10 ⁶ Ω · cm. Transfer roller for equipment.   10. The transfer roller for a liquid developing electrophotographic apparatus according to claim 1, wherein the ten-point average roughness (JIS B 0601) of the cured outer peripheral surface is 7 μm or less. A method for producing a transfer roller for a liquid development electrophotographic apparatus for producing a transfer roller for a liquid development electrophotographic apparatus in which an outer peripheral surface in contact with a photoreceptor is formed of a polyurethane elastic body,
A transfer roller for a liquid developing electrophotographic apparatus to be manufactured is for transferring an image of the photoreceptor to a resin film as a printing material, and is a polyurethane elastic body obtained by reacting a polyester polyol and a bifunctional isocyanate. A method for producing a transfer roller for a liquid developing electrophotographic apparatus, comprising forming a surface and then curing the outer peripheral surface with an isocyanate.   12. The method for producing a transfer roller for a liquid developing electrophotographic apparatus according to claim 11, wherein a solution containing an isocyanate and an organic solvent is brought into contact with the outer peripheral surface and the curing treatment is performed at room temperature.

Images