JP2013035613A - Paper feed roller and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new paper feed roller and an efficient manufacturing method of the paper feed roller, without requiring assembly of a roller body and a shaft, which causes deformation of the roller body and the like, and requires manhours and labor.SOLUTION: In this paper feed roller 1, the roller body 2 and the shaft 3 are integrally formed of a resin composition including urethane-based thermoplastic elastomer and resin beads. The manufacturing method includes a process of integrally forming the roller body 2 and the shaft 3 by injection-molding the resin composition.

Description

  The present invention relates to a paper feed roller incorporated in a laser printer or the like and used for paper feed, and a manufacturing method thereof.

For example, various paper feed rollers are incorporated in a paper feed mechanism in a laser printer, an electrostatic copying machine, a plain paper facsimile machine, a complex machine thereof, or an inkjet printer.
The paper feed roller rotates while in contact with paper (including plastic film, etc.), and conveys the paper by friction. For example, a paper feed roller, a transport roller, a pinch roller, a platen roller, and a paper discharge Examples include rollers.

As the paper feed roller, for example, a roller main body made of a cross-linked product of various rubbers such as urethane rubber and ethylene-propylene-diene rubber (EPDM), the outer peripheral surface of which is a contact surface with paper, and rotation of the roller main body A thing provided with the shaft inserted in the center etc. is used widely.
Recently, it has been studied to form the roller body with a thermoplastic elastomer instead of a conventional rubber cross-linked product, for example, in order to facilitate recycling (for example, Patent Document 1).

Examples of the thermoplastic elastomer include urethane-based thermoplastic elastomers.
As the shaft, for example, a shaft made of a hard resin such as metal or engineering plastic is used.

JP 2008-254845 A

The roller body made of the thermoplastic elastomer is generally formed by, for example, injection molding or by extruding into a cylindrical shape and then cutting to a predetermined length.
Further, the paper feed roller provided with the roller body is generally assembled by press-fitting a shaft having an outer diameter slightly larger than the inner diameter of the through hole into the through hole at the center of the previously formed roller body. It is.

In order to prevent deformation of the roller body due to the press-fitting, measures such as setting a clearance dimension necessary for assembly may be applied to the roller body and the shaft.
However, since the roller body formed by cutting after extrusion molding has low dimensional accuracy, the roller body is likely to be deformed due to insufficient clearance, etc., and in the deformed state, the paper to be conveyed is damaged or slanted. There is a problem that it is easy to go.

Moreover, the thermoplastic elastomer does not have as much rubber elasticity as a rubber cross-linked product and is generally hard, so that once it is deformed, it is not easy to correct it.
In addition, the size of the roller body itself, such as a pinch roller, is particularly small, and assembling one paper feed roller that needs to be incorporated into a single device one by one is troublesome and labor-intensive.

In addition, the smaller the size of the roller body, the more difficult it is to correct the deformation.
SUMMARY OF THE INVENTION An object of the present invention is to provide a novel paper feed roller that does not require assembly of the roller body and the shaft, which causes deformation and the like of the roller body, and efficient manufacture of the paper feed roller. It is to provide a method.

The present invention relates to a paper feed roller comprising a roller main body constituting a contact surface with paper and a shaft disposed at a rotation center of the roller main body, wherein the roller main body and the shaft are made of a urethane-based thermoplastic elastomer. (TPU) and a resin composition containing resin beads are integrally formed.
According to the present invention, the roller main body constituting the paper feed roller and the shaft, that is, substantially the entire paper feed roller are integrally formed of the TPU and the resin composition containing resin beads. It is possible to save the man-hours and labor for assembling the roller body, and it is also possible to prevent the deformation of the roller body accompanying the assembly.

Moreover, according to the present invention, as a TPU, in a state where resin beads are blended, a hardness that can be sufficiently used as a shaft of a paper feed roller, and a relatively hard material that can obtain dimensional accuracy, Further, by blending resin beads with the TPU, a friction coefficient suitable for paper feeding can be imparted to the outer peripheral surface of the roller body.
In other words, the roller body made of TPU that does not contain resin beads particularly causes a phenomenon of sticking to glossy paper, which is likely to cause poor paper feed, but by adding resin beads, the friction coefficient is reduced, It is possible to prevent the sticking and the paper feeding defect accompanying it.

The present invention relates to a roller main body constituting a contact surface with paper, and a paper feed roller manufacturing method including a shaft disposed at a rotation center of the roller main body, and includes a urethane-based thermoplastic elastomer and resin beads And a step of integrally forming the roller main body and the shaft.
According to the present invention, the paper feed roller of the present invention can be accurately and efficiently manufactured by injection molding the resin composition.

  According to the present invention, a novel paper feed roller that does not require assembly of the roller main body and the shaft, which causes deformation of the roller main body and the like, and takes time and labor, and efficient manufacture of the paper feed roller A method can be provided.

It is a perspective view which shows an example of embodiment of the paper feed roller of this invention.

FIG. 1 is a perspective view showing an example of an embodiment of a paper feed roller of the present invention.
With reference to FIG. 1, the paper feed roller 1 of this example includes a roller body 2 and a pair of shafts 3.
Among these, the roller body 2 is formed in a substantially columnar shape having a cylindrical outer peripheral surface 4 as a contact surface with paper. The shaft 3 is formed in a substantially cylindrical shape having an outer diameter smaller than that of the roller body 2.

The roller body 2 and the shaft 3 are integrally formed of the resin composition including the TPU and the resin beads as described above in a state in which the respective central axes L are aligned.
The pair of shafts 3 are integrally coupled to both axial ends of the roller body 2.
The TPU includes, for example, a hard segment having a polyurethane structure and a soft segment having a polyester or polyether structure in the molecule, has thermoplasticity capable of injection molding and the like, and can function as a roller body. Any of various urethane-based thermoplastic elastomers having properties can be used.

Such a TPU is synthesized, for example, by subjecting a diisocyanate, a macropolyol, and a chain extender to a non-polymerization reaction.
Among these, as the diisocyanate, for example, tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), tolidine diisocyanate, 1,6-hexamethylene diisocyanate (HDI), One or two types such as isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), hydrogenated XDI, tetramethylxylene diisocyanate (TMXDI), 1,8-diisocyanate methyloctane, dicyclohexylmethane diisocyanate (hydrogenated MDI: HMDI) The above is mentioned. Of these, 4,4′-diphenylmethane diisocyanate (MDI) is preferred.

Examples of the macropolyol include polyester polyol and polyether polyol. The number average molecular weight Mn of the macropolyol is preferably 500 or more and 5000 or less, particularly 1000 or more and 3000 or less.
By using polyester polyol as the macropolyol, an ester-type TPU whose soft segment has a polyester structure is synthesized. Further, by using polyether polyol as the macropolyol, an ether type TPU whose soft segment has a polyether structure is synthesized.

Examples of the polyester polyol include dehydration condensation of one or two or more ester-forming derivatives such as divalent organic acids, acid esters thereof, or acid anhydrides, and one or more aliphatic diols. Examples include polyester polyols obtained by the reaction.
Examples of the divalent organic acid include aliphatic dicarboxylic acids having 4 to 12 carbon atoms (succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, etc.) and aromatic dicarboxylic acids (phthalic acid, terephthalic acid, isophthalic acid). , Naphthalenedicarboxylic acid, etc.), and alicyclic dicarboxylic acids (hexahydrophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, etc.).

  Examples of the aliphatic diol include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- 1 type, or 2 or more types of C2-C10 aliphatic diols, such as hexanediol, 3-methyl- 1,5-pentanediol, neopentyl glycol, 1,3-octanediol, or 1,9-nonanediol, Can be mentioned.

Examples of the polyester polyol include polylactone diol obtained by ring-opening polymerization of a lactone monomer such as ε-caprolactone.
The polyester polyol is preferably poly (tetramethylene adipate-co-hexamethylene adipate) glycol.
On the other hand, as the polyether polyol, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol obtained by polymerizing cyclic ethers such as ethylene oxide, propylene oxide, and tetrahydrofuran, or two or more of the cyclic ethers are copolymerized. 1 type (s) or 2 or more types, such as a copolyether obtained by making it contain. Of these, polytetramethylene glycol is preferred.

Examples of the chain extender include one or more of aliphatic polyols, alicyclic polyols, aromatic polyols, and the like.
Among these, as the aliphatic polyol, for example, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 -1 type, or 2 or more types, such as -hexanediol, 3-methyl- 1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, and diethylene glycol.

Examples of the alicyclic polyol include 1,4-cyclohexanedimethanol.
Further, examples of the aromatic polyol include one or more of 1,4-dimethylolbenzene, bisphenol A, an ethylene oxide adduct of bisphenol A, or a propylene oxide adduct of bisphenol A.

Moreover, amines can also be used as the chain extender. Examples of the amines include dicyclohexylmethylmethanediamine (hydrogenated MDA) and isophoronediamine (IPDA).
The method for synthesizing the TPU using each of the components may be the same as in the prior art. For example, in the one-shot method, a chain extender is mixed with a macropolyol that has been dehydrated by heating under reduced pressure in advance, and diisocyanate that has been separately heated while stirring under heating is added, and further constant under heating. By continuing stirring for a long time, the above components undergo an addition polymerization reaction to synthesize TPU. The synthesized TPU can be used, for example, by heating to a predetermined temperature, annealing, pulverizing, and pelletizing.

In addition, the addition polymerization reaction is carried out batchwise or continuously, and the mixture obtained by mixing the components is extruded continuously using, for example, an extruder, or continuously conveyed on a conveyor belt for a certain period of time. It can also be used after pelletizing after maintaining at a predetermined temperature.
As described above, the TPU can impart hardness and dimensional accuracy that can be sufficiently used as the shaft 3 to the shaft 3 of the paper feed roller 1 in a state where resin beads are blended. It is preferable to set the hardness.

The specific range of the hardness of TPU can be arbitrarily set according to the blending ratio of resin beads, the hardness required for the shaft 3, etc., but the JIS A hardness at 23 ± 2 ° C. (type A durometer hardness) In particular, it is preferably 60 or more, more preferably 65 or more, and particularly preferably 80 or more, and is preferably 95 or less, and particularly preferably 90 or less.
If the hardness is less than the above range, even if resin beads are blended, the required hardness and dimensional accuracy may not be imparted to the shaft 3. On the other hand, if the hardness exceeds the above range, even if resin beads are blended, there is a possibility that a good friction coefficient suitable for paper feeding cannot be imparted to the outer peripheral surface 4 of the roller body 2.

In order to set the hardness of the TPU to an arbitrary hardness within the above range, for example, when synthesizing the TPU, the types and blending ratios of the diisocyanate, macropolyol, and chain extender that are the raw materials are appropriately changed. That's fine.
The resin beads can be well dispersed in the TPU, and are completely melted by heat when the paper feed roller 1 is manufactured by injection molding or the like, or by the heat and stress during kneading. Any of various resin beads that are not completely compatible with TPU and can maintain a certain degree of granularity in the paper feed roller 1 after molding can be used.

Examples of such resin beads include one or more beads made of acrylic resin such as (meth) acrylic acid ester; styrene resin; polyamide resin such as nylon 12.
The average particle diameter of the resin beads is not particularly limited, but is preferably 1 μm or more, particularly preferably 2 μm or more, particularly preferably 4 μm or more, and is preferably 120 μm or less, particularly 110 μm or less, particularly preferably 100 μm or less.

  If the average particle size is less than the above range, the effect of imparting a good friction coefficient suitable for paper feeding to the outer peripheral surface 4 of the roller body 2 of the paper feeding roller 1 by blending resin beads cannot be sufficiently obtained. There is a fear. On the other hand, when the average particle size exceeds the above range, the fluidity of the resin composition when the paper feed roller 1 is molded by, for example, injection molding or the like is lowered, and the accuracy of the paper feed roller 1 to be manufactured is May decrease.

The blending ratio of the resin beads is 5 parts by mass or more per 100 parts by mass of TPU, preferably 10 parts by mass or more, particularly preferably 20 parts by mass or more, and 60 parts by mass or less, especially 40 parts by mass or less, particularly 30 parts by mass or less. Preferably there is.
If the blending ratio is less than the above range, the effect of imparting a good friction coefficient suitable for paper feeding to the outer peripheral surface 4 of the roller body 2 of the paper feeding roller 1 by blending resin beads may not be sufficiently obtained. There is. On the other hand, when the blending ratio exceeds the above range, for example, the fluidity of the resin composition when the paper feed roller 1 is molded by injection molding or the like is lowered, and the accuracy of the manufactured paper feed roller 1 is improved. May decrease.

In addition to the TPU and resin beads, various additives may be blended in the resin composition at any ratio in order to further adjust the characteristics of the resin composition and the paper feed roller 1. Examples of the additives include inorganic or organic fillers, processing aids such as plasticizers, conductivity imparting agents, various stabilizers, and the like.
The paper feed roller 1 can be manufactured by the manufacturing method of the present invention including the step of integrally forming the roller body 2 and the shaft 3 by injection molding the resin composition.

That is, the injection molding which has the mold cavity corresponding to the whole shape of the paper feed roller 1 in which the roller main body 2 and the shaft 3 are integrally formed with the resin composition which has been melted or softened by heating and / or pressing. The paper feed roller 1 is manufactured by injecting into the mold cavity of the mold for cooling and solidifying by cooling and then taking out from the mold cavity.
According to this manufacturing method, the paper feed roller 1 can be manufactured with high accuracy and efficiency.

The configuration of the present invention is not limited to the example of the figure described above. For example, a recess such as a groove may be formed on the outer peripheral surface 4 of the roller body 2. When the concave portion is provided, paper dust generated from the paper is taken into the concave portion, thereby suppressing a decrease in the coefficient of friction due to the adhesion of the paper dust to the outer peripheral surface 4, and good paper over a longer period of time. Feed can be maintained.
The shaft 3 may be formed in a shape other than a columnar shape such as a prismatic shape for connection to a drive mechanism (not shown).

  In addition, design changes can be made as appropriate without departing from the scope of the present invention.

<Example 1>
TPU [Elastolan (registered trademark) ET880 manufactured by BASF Japan Ltd., ether type, JISA hardness (23 ± 2 ° C.): 80] 100 parts by mass, and resin beads [Gantz Pearl manufactured by Ganz Kasei Co., Ltd. ( (Registered trademark) GBX-10S, made of acrylic resin, average particle size: 4 to 100 μm] 20 parts by mass were blended and melt-kneaded to prepare a resin composition.

Using the resin composition as a molding material, the shape shown in FIG. 1 is obtained by injection molding. The roller body 2 and the pair of shafts 3 are integrally formed, and the outer diameter of the roller body 2 is A paper feed roller 1 having a length of 7 mm, an axial length of 13 mm, an outer diameter of the shaft 3 of 3 mm, and an axial length of 16 mm was manufactured.
<Examples 2 to 4>
Resin in the same manner as in Example 1 except that the proportion of resin beads per 100 parts by mass of TPU was 30 parts by mass (Example 2), 40 parts by mass (Example 3), and 60 parts by mass (Example 4). A composition was prepared, and a paper feed roller 1 having the same shape and the same dimensions as in Example 1 was produced using the resin composition as a molding material.

<Comparative example 1>
Using the same TPU as used in Example 1 alone as a molding material, a paper feed roller 1 having the same shape and the same dimensions as in Example 1 was produced.
<JIS A hardness measurement>
Using the molding materials prepared in each of the above Examples and Comparative Examples, a sample for hardness measurement specified in Japanese Industrial Standard JIS _K7215-1986 “Plastic Durometer Hardness Test Method” was prepared, and the JIS K7215 _{− According to} the test method described in _1986, the JIS A hardness (type A durometer hardness) of each sample at 23 ± 2 ° C. was measured.

<Friction coefficient measurement>
300 gf of the paper feed roller manufactured in each of the above Examples and Comparative Examples was placed on a paper 60 mm wide × 120 mm long (Xerox Business 4200 manufactured by Xerox Co., Ltd.) placed on a Teflon (registered trademark) plate. When rotating at a peripheral speed of 150 mm / sec in a pressed state while applying a vertical load, the conveyance force F applied to the paper is measured using a load cell, and the formula (1):
Friction coefficient = F / 300 (1)
Thus, the friction coefficient was obtained.

  When the friction coefficient exceeded 0.8, it was easy to cause sticking to the glossy paper described above, so that it was defective (x), and when it was 0.8 or less, it was evaluated as good (◯) because the defect was not generated. The results are shown in Table 1.

  From the results shown in Table 1, the entire roller body 2 and shaft 3 constituting the paper feed roller 1 are integrally formed of a resin composition containing TPU and resin beads, so that the assembly of the two is not required. In addition, it has been found that a friction coefficient suitable for paper feeding can be imparted to the outer peripheral surface 4 of the roller body 2 while ensuring sufficient hardness and dimensional accuracy of the shaft 3.

1 Paper feed roller 2 Roller body 3 Shaft 4 Outer peripheral surface

Claims (2)

  A paper feed roller having a roller main body constituting a contact surface with paper and a shaft disposed at a rotation center of the roller main body, wherein the roller main body and the shaft are made of a urethane-based thermoplastic elastomer, and resin beads. A paper feed roller which is integrally formed of a resin composition containing   A method for producing a roller main body constituting a contact surface with paper, and a paper feed roller provided with a shaft disposed at the rotation center of the roller main body, the resin composition comprising a urethane-based thermoplastic elastomer and resin beads A method of manufacturing a paper feed roller, comprising a step of integrally forming a roller body and a shaft by injection molding an article.

Images