JP2002120953A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer having a paper feeding roller having the simple constitution, having durability and excellent in nonstickiness. SOLUTION: In the paper feeding roller of this printer, and in the printer having a silicone rubber paper feeding roller for carrying a recording medium by rotating by abutting to the recording medium, the printer is characterized by setting surface roughness to 1 to 600 micron meter in Ry by covering a roller outer peripheral part with RTV silicone rubber mixed with polyamide resin composition power having an amino group at the end and a vulcanizing agent having an ion group or an acid anhydride group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer for printing on label paper, linerless paper, or the like, and more particularly, to a paper feed roller formed in a cylindrical shape and transporting a recording medium in contact with the recording medium.

[0002]

2. Description of the Related Art In recent years, sticky thermosensitive paper containing a bar code, which has become widespread in supermarkets and convenience stores, can be weighed on the spot in a simple package and the price, weight, item, etc. can be displayed. Has become.

[0003] As this kind of paper feed roller,
For example, silicone rubber, urethane rubber, EPDM rubber, sponge NBR rubber, chloroprene rubber, fluororesin, and those using the rubber roller coated with a film of the aforementioned material are known.

However, the conventional paper feed roller generates a high temperature of 150 ° C. at the time of color development, and is required to have heat resistance. On the other hand, paper feeding ability at a low temperature of -10 ° C is also required, and there are problems in hardness change and abrasion strength.

On the other hand, Japanese Patent Application Laid-Open No. Hei 9-230689 discloses a roller and a rubber composition used for the roller. The roller is composed of a liquid silicone rubber, an NBR rubber, a silicone oil-containing silicone rubber, and a fluororubber on the outermost surface. Coated. In other words, there is only a low frequency of abrasion resistance on the premise of replacement, and the configuration places emphasis on the releasability, and the number of durability is limited. Further, when the soft fluorine rubber on the outer peripheral portion of the roller drops or peels off, the releasability from the adhesive becomes doubtful.

In Japanese Patent Application Laid-Open No. 8-255435, a hard material such as alumina or silica is firmly fixed on the surface with a synthetic resin. Smooth paper feed can be realized by firmly penetrating the paper. On the other hand, when the paper is fed without paper, the directly facing print heads are slid under pressure, so that the print heads wear out and cause printing defects. Further, paper dust is generated due to repeated friction between the hard body and the paper, which causes stains on the periphery and causes a printer failure.

Japanese Patent Application Laid-Open No. H10-78721 discloses a method of chemically bonding a fluorine component by a condensation reaction in order to impart non-adhesiveness to a roller of a copying machine.

However, bonding non-tacky fluorine at low temperatures appears to weaken or limit the non-tacky function. Further, a soft fluorine component is durable and wears, and it is easily considered that the life of the roller is shortened.

Therefore, silicone rubber, which has been widely used in thermal printers, is excellent in cold resistance.
In particular, there is a characteristic that the rubber hardness does not increase even at a low temperature of −20 ° C. or less. As a result, the paper feeding ability at low temperature is excellent, and it shows stable physical properties even at the heat-resistant temperature of 200 ° C. of the electric resistance heating element, and is widely used.

However, even with the paper feed roller made of silicone,
Adhesive paper provided with adhesiveness on the back side of the thermal paper has a problem in that the paper is wound around a paper feed roller and paper cannot be fed unless a special release paper is sandwiched between the papers.

This is a problem to be solved in terms of environmental impacts such as disposal of release paper for single use and loss of petroleum resources. In addition, the thickness of the release paper is increased to make the paper roll thick, so that the release paper is inferior in portability in terms of securing a storage space for the release paper and increasing the weight, and the field of use is restricted. It is also necessary to have high reliability. That is,
Achieves non-adhesiveness to linerless paper without release paper, does not damage the print head when feeding paper without linerless paper, and has a stable paper feed pitch with abrasion resistance even when subjected to a durability test on plain paper There has been a demand for a paper feed roller that can secure the paper feed.

The present invention has been made to solve such a conventional technical problem, and provides a printer having a paper feed roller having durability, good dimensional accuracy, and excellent non-adhesiveness. The purpose is to do.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a printer having a silicone rubber paper feed roller for conveying a recording medium by rotating while contacting the recording medium. An RTV silicone rubber obtained by mixing a polyamide resin composition powder having the same and a vulcanizing agent having an ionic group or an acid anhydride group was coated on the outer periphery of the roller, and the surface roughness was adjusted to 1 to 600 μm in Ry. It is characterized by.

According to the above configuration, even if the recording medium has adhesiveness, the recording medium does not wind around the paper feed roller, and the paper can be fed smoothly and with high durability. In addition, the polyamide resin composition powder does not fall off while ensuring the surface unevenness of the roller, and the abutting member is not damaged.

Further, the composition for coating the outer peripheral portion of the roller includes:
It is also preferable to add a silicone powder, a silica particle, a carbon powder, a mica, a metal powder, a conductive composition, or a water-repellent composition alone or in combination. This makes it easy to stably form the surface shape, and can add additional effects such as reinforcement and conductivity.

The composition for coating the outer peripheral portion of the roller is as follows:
(1) The polyamide resin composition powder has an average particle diameter of 50 to 300 μm and 5 to 50% by weight, (2)
It is also desirable that the RTV silicone rubber has a tensile strength of 40 MPa or more and 30 to 80% by weight, and (3) the silicone powder has an average particle size of 50 to 300 μm and 5 to 50% by weight, and the total is preferably 100% by weight. .

According to the above configuration, it is possible to appropriately maintain the elasticity of the paper feed roller and to obtain appropriate non-adhesiveness. The eccentricity accuracy of the roller can be secured within a certain range.

Further, it is also effective that the composition for coating the outer peripheral portion of the roller which has been vulcanized and formed in advance is formed as a paper feed roller so as to be located at the outer peripheral portion of the roller. According to the above configuration, a strong bond is obtained between the silicone rubber and the polyamide resin composition powder. Therefore, although the silicone rubber poses a problem of adhesion, changing the processing method does not cause a problem.

A composition for coating the outer peripheral portion of the roller,
It is also effective that the outer peripheral portion of the preformed elastomeric roller is covered or integrally formed.

Thus, the present invention can be applied not only to vulcanized rubber but also to elastomer resin. Further, since the roughness of the outer peripheral portion can be easily realized, the valuation in manufacturing can be expanded, and an optimum manufacturing method can be obtained.

The polyamide resin composition powder is a blend of an epoxy group-modified polyolefin and a polyamide or a polyester, and the RTV silicone rubber is an elastic rubber composition having a carboxyl group or an acid anhydride group containing a vulcanizing agent. Is also effective. With the above configuration, the applicable range of the polyamide resin composition powder is expanded.

Here, RTV of RTV silicone rubber is defined as Room Temperature Vulcan.
It is an abbreviation used in the market in the sense of room temperature curing by izing.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a printer according to the present invention will be described below in detail with reference to the drawings. (Embodiment 1) FIG. 13 is a perspective view of a printer according to the present invention for feeding linerless paper 14. The print head 17 prints by generating heat while pressing the linerless paper 17. The applied pressure is transmitted to the roller outer peripheral portion 10 and partially deforms the roller. The driving force of the motor 20 is transmitted to the gear 21 to rotate the roller 1. Linerless paper 1 with the rotation force of roller 1
4 is fed. Therefore, the roller outer peripheral portion 10 performs a paper feeding function while being in close contact with the linerless paper paste.

FIG. 14 is a schematic diagram showing the non-adhesive contact of the present invention where the polyamide resin composition powder 7 and the paste 18 of the linerless paper 14 come into contact. The method of ensuring non-adhesiveness to the adhesive glue 18 forms the space 19 with a stable distribution and a uniform size. The roller of the present invention is shown in FIG.
As shown in FIG. 4, a space is formed between the polyamide resin composition powder 7 and the paste 18. In addition, the polyamide resin composition powder 7 and the roller outer peripheral portion 10 employ a chemically bonded reaction mode. That is, it is due to the bonding between the polyamide resin composition powder 7 having an amino group and the RTV silicone rubber mixed with a vulcanizing agent having an ionic group or an acid anhydride group. Further, the roller 1 and the roller outer peripheral portion 10 are joined by the same silicone.

The function of improving the durability is such that the contact with the thermal paper 14 or the linerless paper paste 18 is not covered with the polyamide resin composition powder 7 and the outer peripheral portion 10 of the RTV silicone with low strength is not contacted. . Also, during printing without paper, the polyamide resin composition powder 7 does not wear on the print head 17 made of ceramic, so that good printing continues. The polyamide resin composition powder 7 itself also deformed under pressure, and showed little wear and a degree of wear equivalent to the life of the printer.

The non-adhesive mechanism of the present invention has been described. Next, the roller 1 of the printer will be described.

FIG. 1 is a perspective view showing the whole of the first embodiment of the present invention, and FIG.
It is A 'sectional drawing. FIG. 11 shows the types and amounts of the materials.

As shown in FIG. 1, the paper feed roller 1 according to the present embodiment includes a roller portion and an outer peripheral portion 10. The roller section is composed of the roller 1 and the primer 2 for improving the close contact with the shaft 2. Outer part 10 is an RTV
It is composed of silicone 4, silicone powder 5, and adhesive resin 7. Here, each process from the raw material to the finish of the roller portion will be described in order.

First, the preparation of the silicone rubber material will be described. 0.8% by weight of a C-4 vulcanizing agent is added to a commercially available silicone rubber for rollers, and the mixture is kneaded with a mixing roller machine (not shown) for 20 minutes.

Next, the vulcanizing step of the roller section will be described. Shaft 2 made of SUM that comes into contact with silicone rubber as shown in FIG.
The primer 3 is applied all over the part and dried at 60 ° C. for 30 minutes. The primer-treated shaft 2 is placed on the rubber mold heated to 175 ° C. while adjusting the jig at the center of the mold, and the upper mold is covered. An appropriate amount of the kneaded silicone rubber unvulcanized product is weighed and injected into a compression molding machine provided with the mold and vulcanized. The primary vulcanization condition was 170 ° C. for 12 minutes, and the silicone rubber was completely cured. Take it out of the mold as shown in Fig. 4, put it in a high-temperature bath,
Roller 1 is treated under secondary vulcanization conditions at 200 ° C. for 4 hours. This means that the by-products from the unreacted vulcanization are scattered, volatile components in the compound are removed, and the compression set properties are stabilized.

Next, the step of polishing the roller 1 will be described. The outer circumference of the roller 1 is polished with a disc-shaped grindstone at a peripheral speed of 18
The outer diameter was processed at 00 rpm. In this step, a predetermined eccentricity accuracy was secured. The surface roughness of the outer peripheral portion after polishing was measured to be 6 μm in Ry, and formed a substantially uniform surface.

Next, the preparation of the RTV silicone material 4 will be described. 30% by weight of commercially available RTV silicone having a tensile strength of 71 MPa and 16% of a powder of a polyamide resin composition having an average particle diameter of 200 μm are added to 70% by weight, a predetermined curing agent is also added, and the mixture is kneaded with a mixing roller machine for 10 minutes.
In order to exhibit non-adhesion, it is important that the polyamide resin composition powder 16 is uniformly dispersed with the viscous RTV silicone rubber 4. Thereby, the non-adhesiveness which makes the above-mentioned glue point-contact can be realized. Further, other fillers described below may be added.

Next, the step of coating the RTV silicone 4 will be described. As shown in FIG. 5, the prepared RTV silicone rubber 9 is formed on a glass plate 8 by screen printing to a thickness of 100 μm. A special jig for keeping the distance between the roller 1 and the glass plate constant is provided to make the film thickness uniform, and the roller 1 after the polishing is rolled on the film. At this time, by adjusting the distance between the shaft 2 of the roller 1 and the glass, a coating film of 50 to 200 μm was formed.

Thereafter, the mixture was placed in a high-temperature bath and cured at 150 ° C. for 1 hour. Further, it is also effective that the composition is formed such that the surface of the roller is coated with the silicone powder while the roller surface is not yet cured.

In the above configuration, since the roughness of the outer peripheral portion can be realized by the composition ratio, the viscosity adjustment, the processing speed, and the like, the valuation in manufacturing can be expanded, and an optimum manufacturing method can be obtained.

Next, a method for evaluating the quality of RTV silicone rubber will be described. When the roughness of the coating layer on the outer peripheral surface was measured with a contact-type surface roughness meter, it was processed to 23 μm in Ry. This range is an essential condition for exhibiting the function of the non-adhesive roller.

Here, when the outermost surface is processed to have a roughness of 1 μm or less in Ry, the outer peripheral portion 10 which comes into contact with the tacky paper coated with an adhesive on the surface of the paper at a high pressure and feeds the paper, The tack paper wraps and loses releasability.
The adhesive strength of the back side of the tack paper varies depending on the paper maker and paper processing maker, but the function of accurate paper feeding and separation of the adhesive cannot be guaranteed in this range.

Further, when the roughness of the outermost surface of the RTV silicone rubber is processed to 600 μm or more in Ry,
An accurate paper feeding function cannot be guaranteed in this range. That is, the occurrence of one-sided contact with the paper and the coefficient of friction (μ) with the paper become low, and a slip phenomenon is observed, so that the paper feeding accuracy cannot be guaranteed. In addition, meandering of the paper and idling of the paper during printing durability occur.

In consideration of not only the use of tack paper but also the use of ordinary thermal paper, the outermost surface roughness is 20 to 1 in Ry.
50 microns is good. The environmental factors affecting non-adhesion include temperature and humidity during use, and the higher the temperature and humidity environment, the higher the adhesiveness, and the lower the temperature and humidity environment, the higher the non-adhesive ratio, with good results. The result is 1 for thermal paper.
Paper feeding was normal even after printing of 10 million, and there was no problem in printing. Even after the printing durability test on the linerless paper, no sticking to the roller outer peripheral portion 10 was observed, and clear printing did not change until the end. There was no particular problem with the combined use of thermal paper and linerless paper. The result proved the high durability and non-adhesiveness of the present invention. The details are as shown in FIG. In the present invention, when the RTV silicone rubber 4 is mixed with a predetermined amount of the polyamide resin composition powder 16 or the silicone powder 5 described later, the RTV silicone rubber 4 has the non-adhesion and abrasion resistance specified above. What can express the property may be used. Such an RTV silicone rubber 4 can be easily selected by an actual test. Specific examples thereof include, for example, a silicone adhesive, a silicone potting material, a silicone gel product, a silicone resin, a silicone surface protective coating agent, and a fluoropolymer. For example, silicone rubber. The addition reaction type may be a condensation reaction type. The RTV silicone rubber 4 can be used alone or in combination of two or more. In other words, for flame retardancy, non-fluidity, thixotropy, heat dissipation, heat resistance, conductivity, solvent resistance, cold resistance, adhesiveness, high strength, electrical contact failure countermeasures, etc. Additives may be added. The form may be one-part or two-part.

The RTV silicone rubber 4 has a tensile strength of 40 MPa or more, a potting time of 12 hours or more, and a rubber hardness of 40 in JIS-A in order to maintain the paper feeding function by mixing an additive of 30% by weight or more. The above RTV silicone rubber 4 is desirable. When the tensile strength is less than 40 MPa, pressure contact with the paper is repeated during the paper feeding test, and the non-adhesiveness is reduced due to the reduction in the paper feeding ability due to the reduction in the outer shape of the roller 1 and the smoothing of the surface due to abrasion. Potting time is 1
If the time is less than 2 hours, the viscosity of the RTV silicone rubber 4 changes sequentially during the operation, and the film thickness becomes uneven. In order to uniformly produce the plurality of rollers 1 with a stable viscosity, the potting time is desirably 24 hours or more.

The blending amount of the RTV silicone rubber 4 is not particularly limited and can be appropriately selected from a wide range. However, it is generally sufficient to set the amount to about 30 to 80% by weight of the total amount of the present composition. 30% by weight
If the ratio is significantly lower than the above range, the resulting composition may have poor durability and rubber elasticity. On the other hand, when the content exceeds 80% by weight, the above-mentioned non-adhesiveness cannot be obtained, and there is a possibility that adhesion or an adhesion phenomenon may occur during printing of tack paper as the paper feed roller 1.

As a rubber which can be combined with a polyamide resin having an amino group at a terminal and a composition thereof,
Ethylene-propylene copolymer obtained by copolymerizing an acid component,
Examples of the composition include one or more compositions selected from nitrile rubbers obtained by copolymerizing an acid component.

These rubbers easily form a strong bond by contacting a powder made of a polyamide resin having an amino group at a terminal and a composition thereof in an unvulcanized state, and then vulcanizing the powder. . The mechanism of this adhesion is the formation of chemical bonds at the interface. A peroxide is preferred as the vulcanizing agent.

Further, instead of the RTV silicone rubber used, any rubber containing a carboxyl group or an acid anhydride group can be equally used. That is, natural rubber (N
R), butadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene- (diene) -rubber (EPM or EPDM), chloroprene rubber (CR),
Isobutene-isoprene rubber (IIR), isoprene rubber (IR), acrylic rubber (ACM), ethylene-acryl rubber and the like can be considered. Further, an appropriate mixture of these various rubbers may be used, or a mixture of a rubber containing a carboxyl group and a rubber not containing the carboxyl group may be used.

Further, in addition to the filler, additives such as conductive material additives, pigments, deterioration inhibitors, stabilizers, and function-imparting agents may be blended. In the present composition, within a range that does not reduce the mechanical strength and processability specified above,
Plasticizers, cross-linking agents, vulcanization accelerators, vulcanization accelerators, mastication accelerators, activators, antioxidants, ozone deterioration inhibitors, ultraviolet absorbers, light stabilizers, tackifiers, rubber softeners, Rubber reinforcing agent, filler, reinforcing agent, foaming agent, foaming aid, internal release agent,
Known lubricants, release agents, slip agents, antifogging agents, flame retardants, antistatic agents, denaturing agents, antioxidants, heat stabilizer coloring agents, scorch preventing agents, coupling agents, preservatives, antifungal agents Rubber additives may be added.

The conductive additives include carbon black, graphite, particulate Ag, particulate Au, particulate Ni, particulate stainless, particulate titanium oxide, tin oxide, particulate conductive zinc oxide, AU-AG, and the like. Ni-Ag composites, silver-coated glass beads and particulate carbon balloons can be mentioned.

Further, various fillers typified by thermoplastic resin, thermosetting resin, glass fiber, carbon fiber, carbon black and the like may be added to these rubbers.

In the present invention, silica powder may be added as a filler, if necessary, as long as the basic physical properties are not changed. The added varieties may be used alone or in combination. When combined and added, a combined effect can be expected. Silicone rubber of this composition to which silica powder is added is used to adjust the surface irregularities and improve the coefficient of friction of the surface to improve paper feedability, and further improve abrasion and durability against inorganic substances contained inside the paper. Used for In order to promote abrasion with paper during non-durable printing and exhibit non-adhesion, the content is desirably 5% by weight or less. However, when the addition amount is much larger than 5% by weight, the non-scratching property of the mating material is reduced, and there is a possibility that the print head of the thermal printer pressurized with a load of about 1 kgf may be damaged. Although the particle size is not particularly limited, the average particle size is usually 10 in consideration of the surface smoothness of the roller 1 and the like.
The thickness may be about micron meter or less, preferably about 2 micrometer or less.

The blending amount of the polyamide resin composition powder 16 is not particularly limited and can be appropriately selected from a wide range. However, it is generally sufficient to set the amount to about 5 to 70% by weight of the total amount of the present composition. If the content is significantly lower than 5% by weight, the resulting composition may have poor durability and abrasion resistance. On the other hand, if it exceeds 70% by weight, the above-mentioned non-adhesiveness and flexibility cannot be obtained, and there is a possibility that the paper feed roller 1 may cause adhesion or adhesion when printing on tack paper.

The polyamide resin having an amino group at the terminal is
Any material having an amino group may be used, and those which do not deform upon contact with the molten rubber are preferable. For example, aromatic nylon, polyamide 46 (hereinafter, PA46), PA66,
PA612 and the like, and particularly, heat resistance,
PA612 is preferably used in terms of water absorption and adhesiveness. In the case of PA612, the elastic modulus is more preferably 400 t / cm ² or more or 500 t / cm ² or more. Further, various stabilizers such as heat stabilizers, antioxidants and light stabilizers, coloring agents for coloring, plasticizers, flame retardants and the like may be added and blended.

Further, the polyamide resin composition powder 16 is
There is no particular limitation as long as an epoxy group is present in the resin composition. It is considered that the epoxy group reacts with the carboxyl group in the rubber to form an ester bond, thereby dramatically improving the interfacial adhesion between the two layers. The resin composition having an epoxy group is composed of bisphenol /
This is a blend of a polymer containing an epoxy group such as an epicrawler hydrin condensate. The synthetic resin mentioned here is
Polyamide resin, PBT resin, PET resin, polyarylate resin, polyacetal resin, polycarbonate resin,
Polysulfone resin, modified PPO resin, modified PPE resin,
It refers to a material to which a PPS resin and a filler are further added. Further, general-purpose resins such as PS resin, PE resin and PP resin may be used instead of the synthetic resin.

In the present invention, there is a silicone powder as a substance which can be further added. Silicone powder 5
Is used to obtain the non-adhesiveness and abrasion resistance of the surface specified above, the non-scratching property of the print head of the mating material, and to keep the eccentricity of the roller 1 in the coating process low. As the silicone powder 5, known ones such as spherical, crushed, scaly, and amorphous can be used. An average particle size of 50 to 300 microns applies.
If the average particle size is less than 50 μm, unevenness on the surface that greatly contributes to the non-adhesive effect cannot be realized because of the high-viscosity RTV silicone rubber. On the other hand, if the average particle diameter is 300 μm or more, the particles fall off and the surface becomes uneven. Preferably, 50 to 150 microns is optimal. These may be used alone or in combination of two or more. The density and shape of the silicone powder material are not particularly limited, but depend on the uneven distribution of the silicone powder due to the appropriate viscosity of the RTV silicone rubber 4, that is, the action of naturally forming unevenness on the surface.

The blending amount of the silicone powder 5 is not particularly limited and can be appropriately selected from a wide range. However, it is generally sufficient to set the amount to about 5 to 50% by weight of the total amount of the present composition. If the content is significantly lower than 5% by weight, the specified performance may not be exhibited. On the other hand, when the content exceeds 50% by weight, the roller 1 of the present composition
, And a high-viscosity RTV silicone rubber mixture is not obtained, so that a stable and uniform film cannot be formed.

In addition to the SUM, SUS, aluminum alloy steel wire, etc., high rigid plastics such as polyphenylene sulfide (PPS), polyetheretherketone (PEEK), liquid crystal polymer (PLA), and polysulfone (PSU) are used on the shaft. It is possible to use, reduce weight, and achieve automation and cost reduction by continuous production.

In addition, a strong bond can be directly formed in the vulcanization step of a composite material comprising a thermoplastic resin and an elastomer without using an adhesive. A strong chemical reaction can be made that is incomparable to conventional bonding using the anchor effect. The chemical reaction is caused by molecular diffusion or chemical bonding. The width of the disorder of the phase structure due to molecular diffusion is 0.1 to 0.5 μm. Although the rubber diffuses to the resin side, extremely strong adhesion is obtained because there is no clear adhesive interface. The chemical bond is obtained by an adhesive force due to a strong radical reaction generated at a contact interface between the resin and the rubber. There is no need to use an organic solvent such as an adhesive or a thinner, and a desired bond can be obtained in terms of environmental protection and working environment.

There are the following three types of tacky paper adhesives to which the present invention is applied. Rubber-based pressure-sensitive adhesives include three types of bases: rubber based mainly on natural rubber, synthetic rubber, and reclaimed rubber, and acrylic ester, and acrylic based based on copolymer and silicone rubber based. , An antioxidant, a softener, a crosslinking agent, a filler and the like. In addition, in addition to the above-mentioned solvent type, there are an emulsion type, a liquid curing type, and a hot melt type in the form of the acrylic pressure-sensitive adhesive.

Further, as a method for coating the roller 1 with the RTV silicone rubber after mixing the silicone powder, a roll coater process, a spraying process, a screen printing process, a pressing method of the above-described embodiment, and the like can be considered. In the above embodiment, attention is paid to the improvement of durability and wear, which is a drawback of silicone rubber, and the surface hardness of the roller 1 is increased by the addition of the polyamide resin composition powder, and an air layer is created on the surface to be pressed. The effect of suppressing the increase in the non-adhesiveness and the increase in the initial starting torque due to the deformation of the rubber on the contact surface, which is observed in the low hardness rubber, was confirmed by providing the uneven pattern.

The printer of the present invention can be applied to impact type printers, ink jet type printers, electrophotographic type printers, and the like, and has the effects of extending the life and improving the durability.

In particular, it is considered to be a proposal for a silicone rubber roller having a rubber hardness of 40 degrees or less according to JIS-A to compensate for the defect of abrasion resistance and abrasion resistance. In other words, the polyamide resin composition powder is repeatedly pressed against the cellulose without the cellulose of the printing paper coming into direct contact with the silicone rubber having a low tear strength, and thus has an effect of stabilizing the change in the friction coefficient during the durable life.

(Embodiment 2) Next, an embodiment 2 of the present invention will be described.FIG. 6 is a perspective view showing an entire embodiment 2 of the present invention, and FIG. 7 shows a main part of the embodiment. It is AA 'sectional drawing. Fig. 11 is a diagram showing the types and amounts of the materials, etc. The material coated on the surface of the paper feed roller is a polyamide resin composition powder 16 having an average particle diameter of 70 μm, and a 24% by weight tensile strength. 56MPa RTV silicone rubber 4
It is formed from 0% by weight silicone powder, 5% by weight silica powder and 1% by weight. As a result, the paper feed was normal even after 10 million printing on the thermal paper, and there was no problem in printing. Even after the printing durability test on the linerless paper, no sticking to the roller outer peripheral portion 10 was observed, and clear printing did not change until the end. There was no particular problem with the combined use of thermal paper and linerless paper. The result proved the high durability and non-adhesiveness of the present invention. The details are as shown in FIG.

(Comparative Example) FIG. 8 is a perspective view showing the entire roller of Comparative Example 3, and FIG. 9 is a sectional view taken along the line AA 'showing the main part of the embodiment of Comparative Example 3.

As shown in the figure, the roller of the present embodiment is composed of a rough shaft 2, a roller 1 and a binder layer 11. FIG. 11 shows the types and amounts of the materials.

The primer 3 is applied to the shaft 2 made of SUM and dried, and then placed in a rubber molding die, and the roller 1 is vulcanized. After the outer periphery is polished to secure a predetermined outer diameter and center run, an epoxy resin binder 11 in which alumina powder 6 and silica powder 7 are mixed is applied to the outer peripheral surface of the roller 1 and dried.

The material coated on the surface of the roller 1 is composed of 55% by weight of alumina particle powder having an average particle diameter of 40 μm, 35% by weight of silica powder having an average particle diameter of 1 to 3 μm, and 10% by weight of an epoxy resin binder. .

As a result, the heat generating portion of the print head was removed before printing 10,000 lines in the durability test.
Details are shown in FIG. Scratching property was observed with respect to the mating material that comes into contact with the roller, which was a factor in causing a failure to damage the print head of a thermal printer which was pressurized with a load of about 1 kgf.

Next, the evaluation method will be described in detail. [Non-adhesion test] About Examples 1-2 and Comparative Example 3,
The coefficient of friction (μ) was evaluated using a friction coefficient evaluator.
As an effect of the present invention, as shown in FIG. 12, a measured value of a friction coefficient (μ) value of a commercially available thermal paper and a friction coefficient (μ) value of a tack paper were measured.

As shown in FIG. 10, the configuration of the measuring jig includes a tension gauge 15, a weight 12 (50 grams), the roller 1 of the present invention, and a thermal paper 14. The roller 1 was rotated in the rotation direction 13 at 50 revolutions / minute, the value of the tension gauge 15 was measured, and the value was calculated by the following formula for calculating the coefficient of friction (μ). Friction coefficient (μ) value = 0.6366197 x ln (measured value of tension gauge (gf) / roller rotation speed (rpm))
: Outer diameter of roller: 105 mm [Abrasion resistance test] The paper feed rollers of Examples and Comparative Examples were incorporated in a printer, and a printing durability test of a length of 50 km was performed. The test conditions were as follows. Roller outer diameter and friction coefficient before and after printing durability were measured using KT50 thermal paper which is widely circulated in Europe and contains many inorganic substances, and TF50 available in Japan.

Here, the dimensional change rate of ± 0.001% or less is indicated by ◎, and the dimensional change rate of less than ± 0.005% is indicated by ○.
Those with 0.005% or more were evaluated as x.

As is clear from FIG. 14, the paper feed rollers of Examples 1 and 2 have a friction coefficient (μ) of about 0.8 for tack paper and about 0.5 for plain paper. Also,
The paper feed rollers of Examples 1 and 2 were excellent in durability characteristics (printing), and also had a good outer diameter change rate without deformation or shrinkage even with thermal paper.

[0070]

As described above, according to the present invention, it is possible to obtain a good paper feed roller which is durable and can feed paper smoothly even on adhesive paper. In other words, the size of the silicone powder secures an appropriate distance from the adhesive paper, realizing a non-adhesive effect. The print head is in direct contact with the silicone powder and has no killing property. The polyamide resin composition powder and the RTV silicone rubber are firmly bonded by molecular diffusion and chemical bonding, and the surface of the paper feed roller responds flexibly to repeated deformation and thermal shock changes during printing durability. The function is maintained. By using RTV silicone having a tensile strength of 40 MPa or more as the base resin, a structure is provided in which the contact paper is worn away during durability. Mixing silicone powder and RTV silicone rubber,
The eccentricity and the outer diameter accuracy, which are the lifelines of the roller, are maintained at the same level as the current state by the existing simple and uniform coating method. By coating a polyamide resin composition powder on the outer periphery of an elastomer or a low hardness rubber whose outer diameter decreases as the number of paper feeds increases, the abrasion resistance is improved and the paper feed life is prolonged. The safety between the polyamide resin composition powder and the RTV silicone rubber is improved without using an organic solvent or other substances that affect the environment.

In such a printer of the present invention, by coating the roller with the silicone composition of the present invention, a paper feed roller having a stable friction coefficient can be obtained accurately and inexpensively. As a result, the sticking of the linerless paper feed roller, which has been a major issue in realizing a linerless printer without a mount, has been resolved, and the system has advanced dramatically.

Further, it has helped to solve the environmental problem corresponding to the depletion of the earth resources, which has been a problem with the linerless method. Functionally, it is considered to be one of the key technologies, such as characterizing product strategies and expanding the range of design freedom along with the trend of miniaturization, weight reduction, and improvement of portability. We think that it is an important proposal for home appliances and consumer products.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the entirety of a paper feed roller 1 according to a first embodiment of the present invention.

FIG. 2 is an AA ′ cross-sectional view showing a main part of the embodiment of FIG.

FIG. 3 is a perspective view of a positional relationship between a shaft 2 and a mold after a primer 3 is applied in Example 1.

FIG. 4 is a perspective view of the roller 1 after vulcanization molding according to the first embodiment.

FIG. 5 is a schematic view of a step of coating the RTV silicone rubber 9 after compounding in Example 1.

FIG. 6 is a perspective view illustrating the entirety of a paper feed roller 1 according to a second embodiment of the present invention.

FIG. 7 is an AA ′ cross-sectional view showing a main part of the configuration of the second embodiment.

FIG. 8 is a perspective view showing the entirety of a paper feed roller 1 according to a comparative example 3;

FIG. 9 is an AA ′ cross-sectional view showing a main part of the embodiment of Comparative Example 3.

FIG. 10 is a principle diagram of a mechanism for measuring a coefficient of friction (μ).

FIG. 11 is a diagram summarizing conditions of an example and a comparative example.

FIG. 12 is a diagram summarizing the results of an example and a comparative example.

FIG. 13 is a perspective view showing a linerless paper and a printer.

FIG. 14 is a schematic diagram of contact between a polyamide resin composition powder and a paste.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roller 2 axis 3 Primer 4 RTV silicone rubber 5 Silicone powder 6 Alumina particle powder 7 Polyamide resin composition powder 8 Glass plate 9 RTV silicone rubber after mixing 10 Peripheral part covered with RTV silicone rubber 11 Epoxy resin binder layer 12 Weight 13 Roller rotation direction 14 Thermal paper 15 Tension gauge 16 Silica powder 17 Print head 18 Glue 19 Space 20 Motor 21 Gear

Claims (6)

[Claims] 1. A printer having a silicone rubber paper feed roller for conveying a recording medium by rotating while contacting the recording medium, comprising: a polyamide resin composition powder having an amino group at an end; an ionic group or an acid anhydride group; RTV silicone rubber mixed with a vulcanizing agent having the following formula: is coated on the outer periphery of the roller, and has a surface roughness of 1 to 600 μm in Ry. 2. The composition for coating the outer peripheral portion of the roller,
2. The printer according to claim 1, wherein a silicone powder, a silica particle, a carbon powder, a mica, a metal powder, a conductive composition or a water repellent composition is added alone or in combination. 3. The composition for coating the outer peripheral portion of the roller,
(1) The polyamide resin composition powder has an average particle diameter of 50 to 300 μm and 5 to 50% by weight, (2)
The RTV silicone rubber has a tensile strength of 40 MPa or more and 30 to 80% by weight, and (3) the silicone powder has an average particle size of 50 to 300 μm and 5 to 50% by weight, which is 100% by weight in total. 3. The printer according to claim 1, wherein: 4. The paper feed roller according to claim 1, wherein the composition for coating the outer peripheral portion of the roller, which has been vulcanized and formed in advance, is formed as a paper feed roller so as to be located on the outer peripheral portion of the roller. Printer. 5. The printer according to claim 1, wherein the outer peripheral portion of the preformed elastomeric roller is coated or integrally formed with the composition for covering the outer peripheral portion of the roller. 6. The polyamide resin composition powder is a blend of an epoxy group-modified polyolefin and a polyamide or polyester, and the RTV silicone rubber is an elastic rubber having a carboxyl group or an acid anhydride group containing a vulcanizing agent. The printer according to any one of claims 1 to 5, wherein the printer is a composition.