JP3770292B2 - Driven roller for printing paper conveyance and printer provided with the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a driven roller for paper conveyance used in a printing apparatus or the like for printing characters or images, and a printer including the same, and more specifically, a specific fluorine-containing urethane elastomer material is provided on a paper surface contact portion of the roller. By using this, the contact surface portion has an appropriate hardness and low friction property, excellent in paper conveyance performance, and excellent in wear resistance and durability of the paper contact portion of the roller, and a driven roller for printing paper conveyance, and this The present invention relates to a printer provided.
[0002]
[Prior art]
In general, a printing apparatus such as a printer is provided with a paper conveyance mechanism including a driving roller 10 and a driven roller 11 as shown in FIG. 3, for example, and the printing paper 12 is sandwiched between the driving roller 10 and the driven roller 11. When the drive roller 10 is rotated after being introduced in the form, the printing paper 12 is supplied or the paper is conveyed.
[0003]
Here, a conventional paper conveyance driven roller will be described with reference to FIG. 2A is a longitudinal sectional view of a conventional paper conveying driven roller, and FIG. 2B is a side view thereof.
[0004]
As shown in FIG. 2, the conventional driven roller 11 is usually a roller base 11a made of a material such as metal or hard plastic, rubber provided on the peripheral surface of the base 11a, etc. The roller peripheral surface member 11b is made of an elastic material such as an elastomer.
[0005]
In the driven roller 11, a rubber member 11b made of natural rubber, synthetic rubber or the like is mounted on the peripheral surface of the roller base 11a, and a paper contact portion is formed where the rubber member 11b and the printing paper come into contact. On the surface of the rubber member 11b, a fluorine resin coating film layer 11c such as a polyfluoroethylene resin film, for example, having a thickness of about 20 μm is formed by applying a fluorine resin coating process.
[0006]
The driven roller 11 configured as described above presses the printing paper 12 sandwiched between the driving roller 10 and the like with a constant load, and rotates as the driving roller 10 rotates.
[0007]
Since the driven roller 11 needs to play a role of properly transporting the printing paper, the member of the driven roller 11 in contact with the printing paper is required to have an appropriate hardness and low roller surface friction as a function. .
[0008]
In order to satisfy such a function, as described above, the conventional driven roller has a rubber member in which a fluorine-based resin coating layer having a thickness of about 20 μm is usually applied to the surface of the member in contact with the printing paper by a coating process. That is, a surface coat rubber member has been used.
[0009]
[Problems to be solved by the invention]
As described above, the conventional driven roller made of a rubber member whose surface is processed with a fluororesin has various attributes such as appropriate hardness, low friction, and elasticity, and sufficiently exhibits its function in the initial use. It was something to do.
[0010]
However, in the conventional driven roller described above, the fluororesin coating layer formed on the surface of the rubber member gradually wears and wears over time, and eventually the coating layer is partially worn away during use. In some cases, the rubber surface disappeared or peeled off locally, and the rubber surface was exposed at the portion.
[0011]
Therefore, the friction coefficient of contact with the printing paper surface is greatly increased, and there is a problem that the proper conveyance function of the printing paper cannot be achieved, or the exposed rubber surface is in contact with the printing surface of the printing paper being conveyed, At that time, there has been a technical problem that the printing surface of the printing paper is contaminated by the exudation of a rubber-specific compound (for example, process oil) and the printing quality is deteriorated.
[0012]
In order to solve the above problem, it is conceivable to increase the thickness of the fluororesin coat layer, but there is a limit to the increase in the layer thickness by the surface coating method, and it is technically difficult to form a thick coat layer. In addition, it has been found that new problems such as inhibition of the homogeneity of the coat layer and inhibition of adhesion to rubber occur.
[0013]
Further, when the coating layer is, for example, polytetrafluoroethylene, the resin itself has a soft hardness, a little insufficient elastic recovery performance, and a slight viscoelastic fluidity. When it is thick, it has been found that the above-mentioned attributes of the resin itself are predominantly exhibited, and inconveniences such as the properties such as elasticity and hardness inherent to the rubber layer of the main body are not sufficiently exhibited as a whole member.
[0014]
For this reason, troubles during use as described above have been avoided for some time, and there has been a strong demand for the appearance of a driven roller having durability even for long-term repeated use.
[0015]
Therefore, the object of the present invention is to eliminate the disadvantages of the conventional driven roller described above, and to maintain various properties such as appropriate hardness, low friction and elasticity even after repeated use over a long period of time. It is an object of the present invention to provide a paper transporting driven roller that can exhibit its function and has excellent durability for use, and a printer including the driven roller.
[0016]
[Means for Solving the Problems]
According to the present invention, in the conveyance follower roller for printing paper used in a printing device or the like for printing characters or images, the fluorine-containing urethane provided with the conveyance paper contact portion of the roller on the roller base surface made of synthetic resin. It comprises an elastomer member, and the fluorine-containing urethane elastomer is an elastomer composition comprising a thermoplastic polyurethane elastomer and a fluororesin, and the fluorine-containing urethane elastomer composition comprises 85 to 90% by weight of a thermoplastic polyurethane elastomer component and a polytetrafluoroethylene component. There is provided a driven roller for transporting a printing paper, characterized in that it is an elastomer composition comprising 10 to 15% by weight, and the roller base has a hole for inserting the shaft of the driven roller.
[0017]
The present invention uses a fluorine-containing urethane elastomer at the contact portion of the driven roller with the printing paper in place of the conventional surface-fluorinated resin coating, and the surface coat layer as in the conventional driven roller. It is a feature that is not provided.
[0018]
Here, it is preferable that the conveyance paper contact portion of the roller is made of a fluorine-containing urethane elastomer member provided on a roller base surface made of synthetic resin, and the conveyance paper contact portion of the roller is a roller base made of synthetic resin. It is desirable to comprise a fluorine-containing urethane elastomer layer laminated on the body surface. Further, it is desirable that the fluorine-containing urethane elastomer member or the fluorine-containing urethane elastomer layer is provided in a thickness of 1/5 to 1/10 based on the driven roller diameter.
[0019]
The fluorine-containing urethane elastomer used for the driven roller member in the present invention is an elastomer composition comprising a thermoplastic polyurethane elastomer as a main component, a fluororesin component such as polytetrafluoroethylene and a small amount of pigment, etc. In addition to excellent mechanical properties such as recoverability, tensile strength, normal and low temperature impact strength, flexibility at low temperature, heat resistance, oil resistance, chemical resistance, ozone resistance, etc., particularly excellent resistance Has wear characteristics.
[0020]
The inventors have selected a material having an appropriate hardness range from this elastomer composition, and when this is used as a member of the conveyance paper contact portion of the driven roller, the friction state with the printing paper under load is good. The present invention has been found based on this finding based on this finding.
[0021]
The elastomer composition used for the driven roller member of the present invention is mainly composed of a thermoplastic polyurethane elastomer (hereinafter, this elastomer is abbreviated as TPU), and this TPU is composed of diisocyanate and polyols or polyesters as starting materials. The polymer chain consists of a rubber component chain part (soft segment) and a molecular constrained component chain part (hard segment) due to hydrogen bonds.
[0022]
The composition and size of each segment can be changed by changing the type, input ratio, polymerization conditions, etc., of the starting material diisocyanate, polyol, polyester, etc., and thereby an elastomer having various physical characteristics. And the like can be selectively prepared.
[0023]
In addition, the hard segment in the TPU molecular chain is heated to a high temperature of a certain temperature or more to dissociate hydrogen bonds, and fluidizes together with the soft segment. Furthermore, it can also be set as a composition by the method of blend-melting with another kind of plastics, for example, a fluororesin.
[0024]
Further, once fluidized TPU is cooled and solidified, it is again phase-separated into the two segment phases to recover rubber elasticity.
[0025]
From these various TPUs, an elastomer with an appropriate hardness (JIS, JIS according to K-7311, A hardness is in the range of about 60 to 90 °) is selected, and a small amount of fluororesin such as polyfluoroethylene resin is selected. The fluorine-containing urethane elastomer of the present invention comprising a composition obtained by blending (usually about 10 to 15%) has an appropriate hardness inherent in the selected TPU and excellent rubber elastic properties, mechanical properties, and other various properties. In addition to maintaining the properties, the intermolecular plasticizing action by the fluororesin such as polytetrafluoroethylene gives excellent surface smoothness and low dynamic friction, that is, good paper feed properties, and further wear resistance is remarkable. It will be improved.
[0026]
Accordingly, the transport driven roller used in the printing paper transport apparatus of the present invention configured as described above can achieve its function sufficiently without providing a surface coat layer unlike the conventional driven roller. All the inconveniences that occur in the roller are eliminated, and the driven roller for transporting the sheet has excellent durability enough for repeated use over a long period of time.
[0027]
According to another aspect of the present invention, there is provided a printing paper conveyance driven roller, comprising the printing paper conveyance driven roller and a driving roller, wherein the printing paper is supplied or discharged by rotating the driving roller. A provided printer is provided. As a result, all inconveniences caused by the conventional driven roller are eliminated, and the printer is sufficiently durable even for repeated use over a long period.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a view showing an embodiment of a driven roller for conveying a printing paper according to the present invention, in which (a) is a longitudinal sectional view thereof and (b) is a side view thereof.
[0029]
As described above, the conventional driven roller is a roller base made of a material such as metal or hard plastic, except for a special shape, as described above. Rubber provided on the peripheral surface of the base, other elastomers, etc. It consists of a rubber member (roller surface member) made of an elastic material. Then, a rubber member (roller surface member) made of natural rubber, synthetic rubber or the like is mounted on the peripheral surface of the roller base at the paper contact portion of the conventional driven roller for printing paper conveyance, and this rubber member (roller surface member) ) Is subjected to a fluorine resin coating process to form a fluorine resin coating film layer such as a polyfluoroethylene resin film, usually having a thickness of about 20 μm.
[0030]
On the other hand, in the paper contact portion of the printing paper transport driven roller 1 of the present invention, an elastomer member (roller surface member) 3 made of a fluorine-containing urethane elastomer is provided on the peripheral surface of the roller base 2 instead of rubber. Formed and ready for use without surface coating treatment.
[0031]
In the present invention, the roller surface member 3 formed on the roller base 2, that is, the fluorine-containing urethane elastomer material constituting the paper contact portion of the roller, has a hardness (JIS, K-7311 JIS, A hardness) of about 60. It is preferable to select and use an elastomer in the range of up to 90 °.
[0032]
In particular, among these, it is particularly preferable to use an elastomer composition mainly composed of a thermoplastic polyurethane elastomer generally abbreviated as TPU and blended with a fluorine resin such as polytetrafluoroethylene. This is preferable from the viewpoint that the paper conveyance characteristics of the driven roller, which are affected by various factors such as elasticity and low surface friction, are excellent and wear resistance is excellent.
[0033]
Further, as a suitable elastomer composition, an elastomer composition having a hardness of 60 to 90 °, a TPU of 85 to 90% by weight and a polytetrafluoroethylene of 10 to 15% by weight, particularly a composition having a fluorine content of about 10%. Can be mentioned. The composition may contain a small amount of pigment, heat stabilizer, flame retardant, weathering agent and the like.
[0034]
As the thermoplastic polyurethane elastomer (TPU), those having an appropriate hardness can be selected and used from commercially available elastomers known per se, such as diisocyanates such as tolylene diisocyanate and diethylene glycol, polyethylene glycol, polypropylene glycol and the like. It is more preferable to use a polyether-based TPU composed of a polycondensate with polyols in terms of hydrolysis resistance, bacterial deterioration resistance (deterioration resistance due to mold, etc.), etc. in addition to low surface friction.
[0035]
In particular, it is preferable to use a polyether-based TPU in which a macropolyol (HO — (— R ₁ —O) n—H) and a micropolyol (HO—R—OH) are used in combination with diisocyanate.
[0036]
In addition to the polytetrafluoroethylene resin (PTFE), the fluororesin blended as a minor component with respect to the TPU, which is the main component, in addition to the polytetrafluoroethylene resin (PCTFE) and the hexafluoroethylene propylene resin (PFEP). ), Vinyl fluoride resin (PVF), vinylidene fluoride resin (PVDF), and the like, among which polytetrafluoroethylene resin is particularly preferable.
[0037]
The preparation of the composition is not particularly limited, and the composition can be prepared by a method known per se, for example, a melt blending method.
[0038]
In the present invention, the sheet contact portion (roller surface member) 3 made of the above-mentioned fluorine-containing urethane elastomer is replaced with irons such as iron, steel, and stainless steel, copper alloys such as brass and gun metal, aluminum or aluminum alloy, and the like. 1 or a material such as a hard engineering plastic such as polyoxymethylene resin, polycarbonate resin, polyester resin, polyamide resin, etc., for example, provided on the peripheral surface of the roller base 2 having the shape shown in FIG.
[0039]
The method for forming the sheet contact portion (roller surface member) 3 made of the fluorine-containing urethane elastomer is to form the roller surface member 3 by injection molding or extrusion molding, and to form the molded product around the roller base 2. There is a method to attach to the surface. Further, the roller surface member 3 made of a fluorine-containing urethane elastomer can be formed integrally with the roller base 2 by using a known molding technique such as outsert. Furthermore, the roller surface member 3 made of a fluorine-containing urethane elastomer can be laminated and formed using means such as fusion.
[0040]
The thickness of the fluorine-containing urethane elastomer member or the fluorine-containing urethane elastomer layer is appropriately set according to the size and usage of the roller, but is usually about 1/5 to 1/10 of the driven roller diameter. Set to layer thickness.
[0041]
The roller surface made of the fluorine-containing urethane elastomer of the driven roller of the present invention formed in this way is subjected to a slight surface smoothing treatment as required, and does not require any special surface processing such as surface coating. The sheet conveying performance suitable as a roller is exhibited as it is.
[0042]
【Example】
“Examples and Comparative Examples”
An elastomer composition of polyether-based TPU: polytetrafluoroethylene resin = 9: 1 by weight ratio (hardness: JIS, A85 °, including a small amount of white inorganic pigment) was prepared. Was fused and laminated to a thickness of 1 mm on the peripheral surface of a polyoxymethylene resin roller base (outer diameter: 3 mm, length: 9 mm) having the shape shown as follows to obtain a driven roller (Example 1) of the present invention. .
[0043]
Separately, the same substrate as the polyoxymethylene resin roller substrate 2 used in Example 1 was used, and surface fluororesin coating processing was performed on this peripheral surface (tetrafluoroethylene resin coating thickness of about 20 μm). A conventional driven roller equipped with a synthetic rubber member was prepared (Comparative Example 1).
[0044]
When the rolling friction coefficient of each driven roller on the front surface of the A4 size copy paper was measured, the roller of Example 1 was 0.5 and the roller of Comparative Example 1 was 0.2.
[0045]
Next, each of these rollers was mounted as a driven roller for transporting printing paper of a printer (Epson MJ-830C, PM-700C type), and A4 copy paper was loaded and transported to each of these printers. In the case of using the driven roller of Comparative Example 1, the coated surface of the roller is partially peeled off due to wear and the rubber surface is exposed due to the conveyance of 10,000 sheets, and the conveyance cannot be performed smoothly and the copy paper surface is attached. Contaminated by kimono.
[0046]
On the other hand, in the case where the driven roller of Example 1 was mounted, there was no trouble in operation even when the 100,000 sheets were conveyed, and no contamination of the conveying paper surface was observed.
[0047]
【The invention's effect】
As described above, the driven roller for printing paper conveyance according to the present invention is a specific fluorine-containing urethane elastomer member in which the paper contact portion (roller surface member) of the roller has appropriate hardness, low friction and excellent wear resistance. As a conventional driven roller using a rubber member for the roller paper contact portion, secondary processing of the roller surface such as a surface fluororesin coating is not required, and even when used repeatedly for a long time, The paper transport troubles due to wear and tear of the coating film, peeling, etc., seen in the driven roller of this can be avoided.
[0048]
In addition, since the fluorine-containing urethane elastomer does not contain a compound such as process oil blended with rubber, these compounds do not exude and adhere to the surface of the transport paper, and the print surface quality of the paper deteriorates due to transport. There is an effect that there is nothing to do.
[0049]
In addition, according to the printer having the driven roller for conveying the printing paper of the present invention, all the disadvantages caused by the conventional driven roller are eliminated, and it is sufficiently durable for repeated use over a long period of time, and the printing quality is deteriorated. There is an effect that there is nothing to do.
[Brief description of the drawings]
1A and 1B are views showing an embodiment of a driven roller for conveying a printing paper according to the present invention, in which FIG. 1A is a longitudinal sectional view and FIG. 1B is a side view thereof.
2A and 2B are diagrams showing a conventional driven roller for conveying a printing paper, in which FIG. 2A is a longitudinal sectional view thereof, and FIG. 2B is a side view thereof.
FIG. 3 is a schematic diagram for explaining a paper transport mechanism of a printer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Followed roller 2 Roller base | substrate 3 Paper contact part (roller surface member)
DESCRIPTION OF SYMBOLS 10 Drive roller 11 Driven roller 11a Roller base | substrate 11b Rubber member 11c Fluorine-type resin coating film layer 12 Printing paper

Claims (6)

  In a transport follower roller for printing paper used in a printing device or the like for printing characters or images, the transport paper contact portion of the roller is composed of a fluorine-containing urethane elastomer member provided on a roller base surface made of synthetic resin, The fluorine-containing urethane elastomer is an elastomer composition comprising a thermoplastic polyurethane elastomer and a fluororesin, and the fluorine-containing urethane elastomer composition comprises from 85 to 90% by weight of the thermoplastic polyurethane elastomer component and from 10 to 15% by weight of the polytetrafluoroethylene component. A driven roller for printing paper conveyance, wherein the roller base has a hole for inserting the shaft of the driven roller.   The driven roller for printing paper conveyance according to claim 1, wherein the conveyance paper contact portion of the roller is made of a fluorine-containing urethane elastomer layer laminated on a roller base surface made of synthetic resin.   The said fluorine-containing urethane elastomer member or a fluorine-containing urethane elastomer layer is provided in thickness of 1/5 thru | or 1/10 on the basis of a driven roller diameter, The Claim 1 or Claim 2 characterized by the above-mentioned. Driven roller for transporting printed paper.   The printing paper conveyance according to any one of claims 1 to 3, wherein the fluorine-containing urethane elastomer has a hardness (JIS, JIS according to K-7311, JIS A hardness) in the range of 60 to 90. Follower roller.   5. The printing paper conveyance according to claim 1, wherein the thermoplastic polyurethane elastomer is a polyol-based multiblock polymer obtained by polycondensation of diisocyanate, high molecular weight polyol and low molecular weight polyol. Followed roller.   A printing paper transport comprising the driven roller for driving a printing paper according to claim 1 and a driving roller, and supplying or discharging the printing paper by rotating the driving roller. A printer with a driven roller.

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