JPH10212039A - Paper feed roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a friction coefficient from changing with the lapse of time by setting the hardness of a paper feed roll made of thermoplastic elastomer in a specific numerical value range in Shore hardness A scale, and forming a carbon layer in which carbon is plasma-polymerized on the surface. SOLUTION: Respective pellet-like materials of polyester series elastomer, polyvinylchloride series elastomer, and polystyrene series thermoplastic elastomer are kneaded by a bench biaxial extruder/kneader, so as to make polymer alloy type material. Meanwhile, polyethylene polymer and plasticizer are mixed, and the mixture is added to the polymer alloy type material. Next a paper feed roll is manufactured by an injection molding machine, and hardness (Shore hardness A scale) 10 deg.-35 deg. is obtained. Next, the roll is set in a plasma processing device, and DLC films of carbon films of about 1μm, about 3μm, and about 5μm are respectiverly formed on the surface, and the paper feed roll is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various printers such as an ink jet printer (hereinafter, referred to as IJP),
Various OA equipment such as copiers and facsimile machines (FAX),
Various paper feed rolls, such as pickups, feeds, and reverses, used in paper feeders such as automatic teller machines (ATMs), are particularly affected by parts that affect image quality and the like, and are affected by ink, pencil, oil stains, and the like. It is suitable for the easy part.

[0002]

2. Description of the Related Art Conventionally, EPDM (ethylene propylene diene rubber), chlorinated polyethylene rubber, silicone rubber, urethane rubber and the like have been used for paper feed rolls for IJP, FAX, ATM and the like.

[0003]

However, these rubber materials have a problem of a decrease in friction coefficient (μ) and a decrease in weather resistance due to blooming, and have a problem in that the friction coefficient is affected by paper dust and the like due to long-term use. There is also the problem that the rate of change is large.

For example, in IJP, special paper such as a glossy film and a coat film is prepared in order to obtain a clear image such as a photo print. When touched, a phenomenon occurs in which the color of the image printed on that portion is lightened. Although such print contamination varies depending on the material of the paper feed roll,
It has not been solved with conventional paper feed rolls.

[0005] As described above, there are many parts which have not been solved for printing contamination. Conventionally, a paper feeding mechanism in which the paper feeding roll is in contact with the back side of the printing surface is employed, or the surface of the paper feeding roll is polished. Measures such as lowering the physical contact pressure have been taken, but have not been fully resolved.

In view of such circumstances, the present invention does not change the coefficient of friction with time, and can be used stably for various types of paper feed of IJP. It is an object to provide a paper feed roll that does not contaminate a dedicated OHP film or the like.

[0007]

According to a first aspect of the present invention, there is provided a sheet feed roll made of a thermoplastic elastomer having a hardness of 10 ° on a Shore A scale.
給 紙 35 ° and a carbon layer formed by plasma polymerization of carbon on the surface thereof.

According to a second aspect of the present invention, in the first aspect, the thermoplastic elastomer is a polymer alloy type material comprising at least two types of thermoplastic elastomers, and the at least two types of thermoplastic elastomers At least one of the rolls is characterized in that the roll contains 20% to 40% by weight of a plasticizer.

According to a third aspect of the present invention, in the first or second aspect, the surface of the paper feed roll is a knurled surface or a grained surface and has a surface that does not have a surface along the radial direction. And a paper feed roll characterized in that the carbon layer is formed on this surface.

[0010] A fourth aspect of the present invention is the paper feed roll according to any one of the first to third aspects, wherein the carbon layer is a DLC film.

A fifth aspect of the present invention is the paper feed roll according to any one of the first to fourth aspects, wherein the thickness of the carbon layer is 0.5 to 3 μm.

In a sixth aspect of the present invention, in any one of the first to fifth aspects, the thermoplastic elastomer is a polyester-based, polyvinyl chloride-based, polystyrene-based, polyolefin-based, or polyamide-based thermoplastic elastomer. The paper feed roll is selected from the group consisting of:

A seventh aspect of the present invention is the paper feed roll according to the sixth aspect, wherein the thermoplastic elastomer comprises a polyester-based polymer, a polyvinyl chloride-based polymer, and a polystyrene-based polymer. .

The paper feed roll of the present invention has a carbon layer, especially a D layer, on the surface of a roll made of a thermoplastic elastomer having a long and low hardness.
It has a LC (diamond-like carbon) film. The bleed on the roll surface is improved, and the surface tackiness is suppressed. In addition, the film is prevented from being wound around the roll.

In the paper feed roll of the present invention, the adhesion and tackiness are suppressed by the carbon layer, but the initial friction coefficient is only 0.1 to 0.2 lower than that without the carbon layer. There is no problem with paper feeding performance. Moreover, there is no adhesion of paper powder,
Since the abrasion resistance is good, the decrease in the friction coefficient μ due to paper passing is extremely small, and the change over time in the friction coefficient is extremely small.

The carbon layer, particularly the DLC film, is formed in a scaly shape by being formed on a thermoplastic elastomer, particularly a specific thermoplastic elastomer described later, and is considered to exhibit the effects of the present invention as described above. It should be noted that even if a DLC film is formed on ordinary synthetic rubber, it does not become a scale-like film due to the influence of an antioxidant and oil in the rubber.

The thermoplastic elastomer constituting the paper feed roll of the present invention is particularly preferably a polymer alloy type material comprising at least two kinds of thermoplastic polymers. Here, the polymer as a component of the polymer alloy type material is an ester type, a vinyl chloride type, a styrene type,
It is selected from the group of olefin-based and amide-based thermoplastic elastomers, and particularly preferably contains a polyester-based polymer, a vinyl chloride-based polymer, and a polystyrene-based polymer. The mixing ratio of these polymers is particularly preferably selected from the ranges of 30 to 60% by weight, 30 to 50% by weight, and 0 to 30% by weight, respectively.

Further, the thermoplastic elastomer of the present invention comprises:
20 to 40% by weight of a plasticizer as an auxiliary component, preferably
It contains 25 to 35% by weight. As a result, the amount of the polymer alloy material is made to have a property very close to that of the vulcanized rubber, and the problem of a decrease in the friction coefficient due to blooming peculiar to the sulfur vulcanized rubber is solved.

Here, as the plasticizer, the two types of polymer alloys are dioctyl phthalate, dibutyl phthalate, di (heptyl, undecyl) phthalate, diisooctyl phthalate, diheptyl phthalate, butyl benzyl phthalate and higher alcohols. Phthalates such as phthalate; mineral oil-based softeners such as paraffin-based process oils, naphthene-based process oils, and aromatic-based process oils; or epoxy-based plasticizers; and one or more of these. Can be selected.

Further, the thermoplastic elastomer of the present invention comprises:
In addition to the polyalloy-type material, a softening agent polymer such as low molecular weight polystyrene, alkyd resin, and polyethylene may be included in order to give the elastomer a softening property.
These softener polymers are polymer alloy type materials 100
It is desirable to add 5 to 20 parts by weight with respect to parts by weight.

Further, the thermoplastic elastomer forming the paper feed roll of the present invention may contain, in addition to the polymer alloy and the plasticizer, other additives as long as the object of the present invention is not impaired.
For example, it goes without saying that an antioxidant, an ultraviolet absorber, a coloring agent, and the like may be contained as necessary.

The hardness of the paper feed roll of the present invention is in the range of 10 ° to 35 ° on the Shore A scale. this is,
This is because the amount of deformation (nip amount) under a constant pressing load is increased to improve the paper feeding characteristics.

Further, the paper feed roll of the present invention preferably has a knurled or grained surface. However, if the surface is perpendicular to the surface, that is, if there is a surface along the radial direction, the DLC film will not be formed and this will cause contamination.
It is preferable that the concave surface of the processing surface is formed in a slope or a curved surface in which the width is reduced in the depth direction.

The paper feed roll of the present invention is provided with a carbon layer, particularly a DLC film, formed by plasma polymerizing carbon on such a roll made of a thermoplastic elastomer.

Here, the carbon layer is preferably applied to a thickness of 0.5 to 3 μm, preferably 1 to 2.5 μm. This is to maintain a good friction coefficient μ. That is, there is a substantially half-proportional relationship between the thickness of the carbon layer and the coefficient of friction μ. For example, when the initial μ is 2.7 when the thickness of the carbon layer is 0.5 μm, the carbon layer is 1, 2, 3, 4 μm
Then, the friction coefficient μ is 2.5, 1.8,
This is because it changes to 1.5 and 0.9.

As a method for forming such a carbon layer, a plasma CVD method or the like can be mentioned. Further, for example, as a plasma raw material gas in the case of forming by a plasma CVD method, a hydrocarbon compound gas generally used for forming a carbon layer, such as methane and ethane, is used, and the temperature is 20 to 25 ° C., the degree of vacuum is 0.1 Torr, (RF)
In a state of 100 to 300 W of power, for example, 30
The film can be formed with a flow of 100 CCM and a film formation time of 20１００100 minutes.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the following examples, which do not limit the scope of the present invention in any way.

Rolls made of thermoplastic elastomers having formulations 1 to 4 shown in the following table were produced. In particular,
Pellets of polyester thermoplastic elastomer, polyvinyl chloride thermoplastic elastomer, and polystyrene thermoplastic elastomer are kneaded with a desktop twin-screw extruder / kneader (MP2015 type; manufactured by Tubaco Yokohama Sales Co., Ltd.). As a result, a polymer alloy type material was obtained. On the other hand, a 160 ° C. electric heating roll (manufactured by Yokoyama Kikai Seisakusho)
, A polyethylene polymer and a plasticizer (butylbenzyl phthalate) were mixed, and this mixture was added to the above polymer alloy type material. Next, an injection molding machine (IS50EP-
1.5A, Toshiba Machine Co., Ltd. injection pressure 2000kg /
cm2, the molding temperature was 150 ° C at the lower part of the hopper, the cylinder hopper side was 155 ° C, the center was 160 ° C, the nozzle side was 165 ° C, and the mold temperature was 50 ° C to prepare a paper feed roll. Roll dimensions: feed roll: inner diameter 16 mm x outer diameter 24 mm x length 23.5 mm; reverse roll: inner diameter 17 mm x outer diameter 27 mm x length 23.5 m
m.

The hardness (Shore A scale) of each roll was measured.

From the results shown in Table 1, it can be seen that the composition 3 containing a small amount of plasticizer of 10 parts by weight has a hardness of 48 and is too hard for a paper feed roll, while the composition 4 containing a large amount of a plasticizer of 50 parts by weight has a large settling amount. And could not be used as a paper feed roll.

[0031]

[Table 1]

Next, the roll of Formulation 2 was set in a plasma processing apparatus, and methane was used as a raw material gas at a temperature of 0 to 0.
30 to 100 CCM of methane at 25 ° C., vacuum of 0.1 Torr, high frequency (RF) power of 100 to 300 W
DLC films of 1 μm, 3 μm, and 5 μm were respectively formed with a flow time of 20 to 100 minutes to form feed rolls of Examples 1 to 3.

For comparison, a film without a DLC film (Comparative Example 1) and a film with a 6 μm DLC film (Comparative Example 2) were prepared.

Using each of these paper feed rolls, printing was performed on the glossy film exclusively for IJ, and print contamination was visually checked. No contamination was found with the paper feed rolls of Examples 1 to 3. With the paper feed roll of Comparative Example 1, printing contamination was observed. In addition, the sheet feeding roll of Comparative Example 2 was unusable as a sheet feeding roll due to an abnormal increase in surface hardness.

Further, when the ink dots for printing using the paper feed roll of Example 2 were compared with the ink dots for printing using the paper supply roll of Comparative Example 1, the results were as follows. The ink had sufficiently penetrated the film to form dots having an average diameter of about 113 μm. On the other hand, in the case of Comparative Example 1, the film did not sufficiently penetrate into the film, and had dots with an average diameter of about 93 μm. This indicates that the portion where no ink was present increased, leading to print contamination. Was.

Next, the change in the friction coefficient μ was measured using each paper feed roll. The result is shown in FIG. As a result, although the feed roller of Comparative Example 1 had a high initial friction coefficient,
When passing about 10K (10,000 sheets), the coefficient of friction was greatly reduced, but the feed rollers of Examples 1 to 3 did not show a large change in the coefficient of friction even after passing 50K or more.

Further, when the amount of reduction in the height of the knurl after passing through 50K was measured for each paper feed roll,
The result of FIG. 2 was obtained. According to this, the feed rolls of Examples 1 to 3 had good abrasion resistance and a small amount of wear, but the feed roll of Comparative Example 1 showed a decrease in the knurl height of 5% in the case of the example. It was more than twice as large.

[0038]

As described above, since the paper feed roll of the present invention uses a specific thermoplastic elastomer material and has a carbon layer on its surface, it has a sufficient frictional force for conveying the paper. The change of the surface state due to friction is minimized, the stable transport force can be maintained for a long time, and there is no contamination to the special gloss film, the special OHP film, etc., and the low temperature characteristics It has excellent weather resistance and ozone resistance.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change in a friction coefficient of a paper feed roll in a paper passing test.

FIG. 2 is a diagram illustrating a reduction amount of a hill height of a knurl of a paper feed roll in a paper passing test.

Claims (7)

[Claims] 1. A paper feed roll made of a thermoplastic elastomer, having a hardness of 10 ° to 3 ° on a Shore A scale.
A paper feed roll having a range of 5 ° and a carbon layer formed by plasma polymerization of carbon on the surface thereof. 2. The thermoplastic elastomer according to claim 1, wherein the thermoplastic elastomer is a polymer alloy type material composed of at least two kinds of thermoplastic elastomers, and at least one of the at least two kinds of thermoplastic elastomers is a plasticizer. 20% to 40% by weight. 3. The carbon paper layer according to claim 1, wherein the surface of the paper feed roll is a knurled surface or a grained surface and has no surface along the radial direction. A paper feed roll characterized in that a paper roll is formed. 4. The paper feed roll according to claim 1, wherein the carbon layer is a DLC film. 5. The paper feed roll according to claim 1, wherein the carbon layer has a thickness of 0.5 to 3 μm. 6. The method according to claim 1, wherein the thermoplastic elastomer is selected from the group consisting of polyester, polyvinyl chloride, polystyrene, polyolefin, and polyamide thermoplastic elastomers. Characteristic paper feed roll. 7. The paper feed roll according to claim 6, wherein the thermoplastic elastomer comprises a polyester-based polymer, a polyvinyl chloride-based polymer, and a polystyrene-based polymer.