JP3339628B2 - Recording medium feed roller, driven roller, and recording apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the printing of characters or images on various recording media such as plain paper, coated paper having a printing layer on the surface, OHP (overhead projector) sheets, glossy paper, glossy film and the like. The present invention relates to a recording medium feeding roller for conveying a recording medium used in a recording apparatus for recording (printing) and a recording apparatus including the same.

[0002]

2. Description of the Related Art As an example of a conventional recording medium feeding roller for conveying a recording medium, there is a paper feeding roller of an ink jet printer described in JP-A-10-120234. The paper feed roller is disposed close to the upstream side of the recording head, and is formed of a set of a driving roller that contacts the back side of the recording paper as a recording medium and a driven roller that contacts the recording surface side of the recording paper. . The drive roller is driven to rotate while the amount of rotation is controlled using a drive motor as a power source.The driven roller rotates following the rotation of the drive roller, and the recording paper is sandwiched from the front and back by the nip portions of both rollers. The recording paper is sent to the recording head side while being pressed.

[0003] The drive roller has irregularities on its surface by integrally attaching ceramic powder to the surface of the high-rigidity roller. And the ceramic powder,
It is fixed to the surface of the high-rigidity roller by an adhesive mainly composed of an acrylic resin. Due to the surface unevenness structure of the ceramic powder, a sufficient friction coefficient can be secured even for a slippery recording paper such as a film, so that it can be conveyed with high accuracy and durability can be improved. .

In the driven roller, a coating layer made of a low friction material fluororesin (for example, polyfluoroethylene resin) is formed on the surface of an elastic roller made of rubber or the like. The thickness of this coat layer is 5 μm to 20 μm. The reason that the driven roller is configured in this way is that it needs to play a role of properly transporting the recording paper by the combination with the driving roller, and therefore, the nip, which is the portion of the driven roller that comes into contact with the recording paper, This is because the unit is required to have the following first to seventh functions as its functions.

First, the surface has a low coefficient of friction. An appropriate coefficient of friction is desirably 0.3 or less. However, at least 0.5 or less can be used, but more preferably 0.25 or less. If the friction coefficient is high, there is a risk that the leading edge of the sheet may be turned up when it bites into the nip portion, or the leading edge of the sheet may be broken when the driving roller is rotated in the reverse direction after the skew removal sequence.
Conventionally, a fluorine resin coating layer is provided on the surface of the rubber elastic roller to reduce the friction coefficient (0.25 or less) of the surface of the driven roller, but without being affected by the internal rubber elastic roller. The thickness of the coating layer is 5
It is determined to be at least μm.

Second, there is a continuity in the state of the low friction coefficient. This is inevitably required from the viewpoints of the durability and functional stability of the driven roller.

[0007] Third, it has appropriate elasticity. If this hardness is expressed as hardness as appropriate elasticity, the appropriate hardness is required to be in the range of about 60 ° to 95 ° in terms of JIS, A hardness according to JIS, K-7311. The drive roller whose surface has a high friction coefficient by adhering the ceramic powder integrally to the surface of the high-rigidity roller as described above, the surface of the driven roller when the hardness of the driven roller forming a pair is high. There is a risk of scraping or damage. Therefore, the driven roller is required to have the appropriate elasticity from the viewpoint of durability with respect to the drive roller. If the thickness of the fluororesin coating layer is too large, the surface hardness increases and it becomes impossible to maintain appropriate elasticity. Therefore, conventionally, the thickness of the fluororesin coating layer is determined to be 20 μm or less.

Fourth, a compound such as a plasticizer is not eluted from the inside of the rubber. Usually, a rubber-made roller contains a compound peculiar to rubber such as a plasticizer. When this compound elutes to the surface of the driven roller over time, the compound is transferred to the recording surface of the recording paper. For example, the dot diameter of the printed ink becomes small, the part where the compound adheres and the part where the compound does not adhere become a pattern, and the image quality is deteriorated due to roller trace marks. May have occurred. Further, when the eluted compound comes into contact with an adhesive (mainly for fixing the ceramic powder to the surface of the high-rigidity roller) containing the acrylic resin or the like as a main component on the surface of the opposing drive roller, In some cases, a problem occurs in which the acrylic resin is dissolved by a chemical reaction. Conventionally, a fluorine resin coating layer is provided on the surface of the rubber elastic roller to prevent the compound from being eluted. From the viewpoint of ensuring this elution prevention effect, the thickness of the coating layer is set to 5 μm or more. It is decided.

Fifth, the shape accuracy is high. The shape accuracy of the driven roller is required to have an accuracy in which the cylindricity with respect to the outer diameter is within 4%. If the shape accuracy is low, the rotation speed of the driven roller greatly fluctuates, and the behavior of the nip portion with the driving roller becomes unstable, which may cause a disturbance in the paper feeding accuracy.

Sixth, high creep resistance. Normal,
The driven roller is pressed against the surface of the driving roller, and depending on the material of the driven roller, creep deformation occurs when the driven roller is left unattended. If this deformation exceeds a certain amount (approximately 4% of the outer diameter of the driven roller), the paper feeding accuracy may be disturbed due to the instability of the pressing force due to the fluctuation of the peripheral speed of the driven roller. Because there is.

Seventh, good ink resistance. The driven roller is close to the scanning area of the recording head, and it is assumed that ink adheres to the driven roller for some reason.
Therefore, the driven roller needs to be made of a material that is not easily affected by ink.

[0012]

SUMMARY OF THE INVENTION Conventional driven rollers are:
Since a coating layer made of a low friction material fluororesin is formed on the surface of an elastic roller made of rubber (eg, chlorinated polyethylene) as described above, a low friction coefficient, moderate elasticity (rubber hardness), Regarding various functions such as elution prevention, the functions were sufficiently exhibited in the early stage of use.

However, in the conventional driven roller, the fluororesin coating layer gradually wears while being repeatedly used, and it is sometimes impossible to maintain the state of the initial low coefficient of friction. In particular, when the drive roller has a high friction coefficient on the surface of the high-rigidity roller by integrally attaching abrasion-resistant particles such as ceramic powder to the surface, specifically, about 10 sheets of A4 size paper At about 2,000 sheets, there was a tendency that the state of the initial low coefficient of friction could not be maintained. As a result, the coefficient of contact friction with the recording paper surface increases,
In some cases, a problem arises in that the proper transport function of the recording paper cannot be exhibited. Further, when the coating layer is worn and the exposed rubber surface comes into contact with the printing surface of the printing paper being conveyed, the recording (printing) surface of the recording paper is contaminated by the elution of the rubber-specific compound such as a plasticizer. As a result, there is a case where a problem that causes a decrease in recording quality occurs.

An object of the present invention is to provide a recording medium feeding roller comprising a set of a driving roller and a driven roller, wherein the driving roller has a high friction coefficient by dispersing wear-resistant particles on its surface. Even if there is a driven roller, the first to seventh functions such as low friction coefficient, low friction coefficient state persistence, appropriate elasticity, compound elution prevention, etc. can be sufficiently performed even in long-term repeated use. It is an object of the present invention to provide a recording medium feeding roller which is capable of exerting the same and has excellent use durability, and a recording apparatus having the same.

[0015]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a driving roller which is disposed close to an upstream side of a recording head and contacts a back side of the recording medium; A recording medium feed roller for feeding the recording medium to the recording head side while nipping the recording medium from the front and back at a nip portion of the both rollers, comprising a set of a driven roller contacting a recording surface side; The drive roller has a high-friction layer integrally formed on the surface of a high-rigidity roller base, and the high-friction layer uniformly disperses the abrasion-resistant particles and the abrasion-resistant particles and forms the abrasion-resistant particles. An adhesive layer that firmly holds a part of the high-rigidity roller in the distal end side in the radial direction exposed to the surface, wherein the driven roller has a surface in contact with a recording medium made of a low friction member, The low friction member
Is a thermoplastic elastomer and a fluorine-containing thermoplastic elastomer composed of a composition mainly composed of a fluororesin .
An elastic part having a coefficient of friction of 0.4 to 0.5, and by coating a surface of the elastic part with a fluororesin,
And a fluororesin coating layer having a friction coefficient of 0.3 or less .

According to the present invention, the high-friction layer of the drive roller has the abrasion-resistant particles dispersed almost uniformly in the adhered layer, and the dispersed particles have an acute contact with the recording medium. Since it is configured so as to be able to stably exhibit high frictional resistance not only on plain paper and the like but also on a smooth sheet such as a glossy film. Therefore, the transport accuracy is stable regardless of the paper quality. Further, since the paper powder hardly adheres to the particle portion and peels off immediately if it arrives, the frictional resistance does not decrease over the long term, and the conveyance accuracy can be maintained high.

The driven roller used in combination with the driving roller having the above structure has a low friction member having a surface in contact with the recording medium, and the low friction member is mainly composed of a thermoplastic elastomer and a fluororesin. An elastic part made of a fluorinated thermoplastic elastomer made of the following composition and a fluororesin coating layer coated on the surface of the elastic part. The fluorine-containing thermoplastic elastomer, which is an elastic portion forming the base of the low friction member, has a surface friction coefficient of 0.4 to 0.5. Since the surface of the elastic portion made of the fluorine-containing thermoplastic elastomer having a relatively low friction coefficient is further coated with a fluororesin coating layer having a low friction coefficient, the driven roller has a surface friction coefficient of 0.3. As described below, the requirement for exhibiting the function (first function) having the low friction coefficient can be sufficiently satisfied.

The low-friction member does not have a structure in which the surface of a rubber elastic roller made of a normal rubber such as chlorinated polyethylene is covered with a fluorine coat layer as in the prior art, but has an elasticity made of the fluorine-containing thermoplastic elastomer. The surface is coated with a fluororesin coating layer with the base as a base. The inventor confirmed that the low friction member composed of the fluorine-containing thermoplastic elastomer and the fluororesin coat layer has a longer period of time than the low friction member composed of the conventional rubber such as the conventional chlorinated polyethylene and the fluororesin coat layer. A low friction state of the surface could be maintained over a long period of time. The reason is presumed to be that the adhesion strength between the surface and the fluororesin coat layer is higher in the fluorine-containing elastomer than in the ordinary rubber. Therefore, unlike the conventional case, there is little risk that the fluororesin coating layer will be worn out due to repeated use for a long period of time, and the rubber elastic roller will gradually appear, making it impossible to maintain a state of a low friction coefficient. Moreover, the low friction member has a low friction coefficient because the inside is a fluorine-containing thermoplastic elastomer having a relatively low friction coefficient (0.4 to 0.5) even if the fluororesin coating layer on the surface is slightly worn. State is maintained within a range that does not cause any problem even if it slightly drops. Accordingly, the second function of maintaining the low friction coefficient state can be exhibited.

Furthermore, the elasticity of the fluorine-containing thermoplastic elastomer forming the base of the low friction member is 60 ° to 95 ° in hardness (JIS, A-hardness according to JIS, K-7311) in the same manner as ordinary rubber. Since the range can be easily set, a moderate elasticity (third function) required for the surface of the driven roller can be easily provided. Although the elasticity is strictly reduced by coating the surface of the fluorine-containing elastomer with a fluororesin coating layer, the coating layer is formed by setting the thickness of the coating layer to a range where the elasticity reduction does not substantially cause a problem. The problem of the decrease in elasticity due to this can be prevented.

Furthermore, since the fluorine-containing thermoplastic elastomer hardly contains a compound such as a plasticizer, the compound does not elute to the surface over time. Therefore, even if the fluororesin coat layer on the surface is worn, the compound comes into contact with the adhesive mainly composed of the acrylic resin or the like present on the surface of the opposing drive roller, thereby chemically reacting with the acrylic resin or the like. The problem of dissolving the acrylic resin by reaction does not occur.

The present inventor has confirmed by the following test method that the elution which causes a problem in recording (printing) quality is not actually observed. Several driven rollers made of the fluorine-containing thermoplastic elastomer are placed on a nickel-plated steel plate coated with an acrylic resin, and further pressed by a weight from above. The pressing force at this time is assumed to be the maximum pressing force in a state where the recording device is actually mounted, and is approximately 30%.
0 gf. In this state, 62
C. and left for 24 hours. As a result, on the contact surface between the driven roller and the acrylic resin, no traces or abnormalities such as softening due to elution of the compound such as the plasticizer were observed.

According to a second aspect of the present invention, in the recording medium feed roller according to the first aspect, the fluorinated thermoplastic elastomer is mainly composed of a thermoplastic polyurethane elastomer and a fluororesin. There is a feature. According to the present invention, since a urethane-based thermoplastic polyurethane elastomer is used, by providing a fluororesin coating layer on this surface, each of the above functions can be easily provided at a low cost with a simple production.

According to a third aspect of the present invention, there is provided a recording medium feeding roller according to the first or second aspect,
The thickness of the fluororesin coating layer is characterized by being 5 μm to 20 μm. When the thickness is 5 μm or more, the low friction function of the fluororesin coating layer can be surely exhibited, and the durability can be secured.
By doing so, the coating layer can be formed such that the decrease in elasticity of the fluorine-containing thermoplastic elastomer constituting the base hardly causes a problem.

According to a fourth aspect of the present invention, in the recording medium feeding roller according to any one of the first to third aspects, the wear-resistant particles are uniformly formed on the roller surface in a single layer state. The coating layer is dispersed and has a thickness smaller than the average particle size of the wear-resistant particles.

According to the present invention, the abrasion-resistant particles are uniformly dispersed in a single layer state on the roller surface to form surface irregularities. The outer diameter can be kept small within the range of variation in particle diameter. Accordingly, in the state of contact with the recording paper or the driven roller, the entire outer surface of the drive roller can be almost uniformly contacted, and the conveyance accuracy of the recording medium can be improved. The driven roller, which has a low friction member formed by coating the surface of a fluorine-containing thermoplastic elastomer with a fluororesin coating layer on the surface, and forms a pair with the drive roller, has a low friction coefficient and a low friction coefficient state. Various functions such as properties, moderate elasticity, and prevention of compound dissolution can be sufficiently exerted even after long-term repeated use. Therefore, the recording medium feed roller has excellent use durability.

According to a fifth aspect of the present invention, in the recording medium feed roller according to any one of the first to fourth aspects, the wear-resistant particles are made of a ceramic such as alumina or silicon carbide. It is characterized by becoming. Since the ceramic particles are used in this manner, the conveyance accuracy is not affected by the paper quality and the effect of being not affected by the paper dust can be obtained more reliably, and based on the property of being hard and less susceptible to plastic deformation. The durability is further improved. Moreover, it is inexpensive.

According to a sixth aspect of the present invention, in the recording medium feeding roller according to any one of the first to fifth aspects, the adhesion layer is made of an acrylic adhesive. And Thereby, the abrasion-resistant particles can be easily manufactured and firmly fixed to the surface of the high-rigidity roller.

According to a seventh aspect of the present invention, in the recording medium feed roller according to any one of the first to sixth aspects, the high friction layer uniformly removes the wear-resistant particles. The mixed liquid base material is sprayed on the surface of the high-rigidity roller, and the liquid base material is subjected to hardening treatment to form the adhered layer. Thereby, a simple manufacturing method can be used. The curing process is determined by the type of the liquid base material to be used, and includes a curing process of drying at room temperature (room temperature-curable acrylic adhesive) and a curing process of heating (thermosetting epoxy adhesive).

According to an eighth aspect of the present invention, in the recording medium feeding roller according to any one of the first to seventh aspects, the size of the wear-resistant particles is 20 μm in average particle size. ７０70 μm.

If the abrasion-resistant particles are too large (70 μm or more), the recording paper is easily damaged, and if too small (20 μm or less), clogging is apt to occur due to paper dust or the like, and the required friction coefficient is obtained. It is not possible.

According to a ninth aspect of the present invention, in the recording medium feeding roller according to the eighth aspect, the particle diameter of the wear-resistant particles dispersed in the high friction layer is an average particle diameter. Particle size A selected from the range of 20 μm to 70 μm
It is characterized in that it is aligned within a range of ± 20% around [μm].

According to the present invention, since the high-friction layer is formed by dispersing the wear-resistant particles having a substantially uniform particle size substantially uniformly, the longitudinal direction of the roller surface is not limited in both the circumferential direction and the roller diameter direction. And the paper feeding accuracy can be improved. That is, the particle size of the wear-resistant particles is determined by the selected particle size A [μ
m] (for example, 50 μm), the uniformity of the roller diameter can be easily and sufficiently secured, and the paper feeding accuracy can be improved.

According to a tenth aspect of the present invention, in the recording medium feeding roller according to any one of the first to ninth aspects, the wear-resistant particles are distributed with respect to the area of the surface of the high friction layer. The density is 20% to 80%. Thus, it is possible to reliably prevent the occurrence of a layered (dense) state of the particles based on the distribution density being too large and the shortage of the projections due to the particles based on the distribution density being too small and the reduction of the frictional resistance due to the shortage.

[0034] The invention according to claim 11 of the present application is the recording medium feed roller according to any one of claims 1 to 10, wherein the fluorinated thermoplastic elastomer of the driven roller is a main component thereof. The thermoplastic polyurethane elastomer component is 85 to 90% by weight, and the polytetrafluoroethylene component is 10 to 15% by weight.

According to the present invention, the ratio of the main components of the fluorine-containing thermoplastic elastomer constituting the base of the low friction member is such that the thermoplastic polyurethane elastomer component has a ratio of 85 to 9%.
By setting the content of the polytetrafluoroethylene component to 0% by weight and the content of the polytetrafluoroethylene component to 10% to 15% by weight, a driven roller having a low-friction member having the above functions can be easily manufactured. In addition, a small amount of pigment can be included in addition to the main component. Specifically, as a driven roller having a low friction member having a fluororesin coating layer formed on its surface, its mechanical properties such as its elasticity, elastic recovery, tensile strength, room temperature and low temperature impact strength, and flexibility at low temperature. Properties, heat resistance, oil resistance, chemical resistance,
Not only has excellent ozone resistance and the like, but also has particularly excellent wear resistance.

According to a twelfth aspect of the present invention, in the recording medium feeding roller according to the second or eleventh aspect , the thermoplastic polyurethane elastomer is obtained by polycondensing diisocyanate, high molecular weight polyol and low molecular weight polyol. It is characterized by being the obtained polyol-based multi-block polymer.

The thermoplastic polyurethane elastomer used for the driven roller member of the present invention (hereinafter, this elastomer is abbreviated as TPU) is obtained by a polycondensation reaction using diisocyanate and polyols or polyesters as starting materials as described above. The polymer chain is composed of a rubber component chain portion (soft segment) and a molecular constrained component chain portion (hard segment) due to hydrogen bonding.

The composition and size of each segment can be changed by changing the types, input ratios, polymerization conditions, etc. of the above-mentioned starting materials, such as diisocyanate, polyol, polyester, and the like, thereby obtaining various physical properties. A polymer consisting of an elastomer having the following can be selectively prepared.

The hard segments in the TPU molecular chain are dissociated from hydrogen bonds by being heated to a certain temperature or higher, and are fluidized together with the soft segments. Alternatively, the composition may be formed by a method of blending and melting with another kind of plastic, for example, a fluororesin. Further, the TPU once fluidized is cooled and solidified to be phase-separated into the two segment phases again, thereby recovering rubber elasticity.

According to a thirteenth aspect of the present invention, in the recording medium feed roller according to any one of the first to twelfth aspects, the low-friction member is formed by a half of a driven roller diameter. It is characterized by being provided with a thickness of 0.5 to 1/10. By determining the thickness of the low friction member based on such criteria, it is possible to easily achieve a good structural balance. For example, when the diameter of the driven roller is 5 mm, the thickness of the low friction member is 0.5 mm to 2 mm.

According to a fourteenth aspect of the present invention, in the recording medium feed roller according to any one of the first to thirteenth aspects, the hardness of the elastic portion made of the fluorine-containing thermoplastic elastomer (JIS, J according to K-7311
IS, A hardness) in the range of 60 ° to 95 °.

From the various TPUs, a suitable hardness (JI
S, K-7311, JIS, A hardness in the range of about 60 ° to 95 °), and blend a small amount (usually about 10 to 15%) of a fluororesin such as polyfluoroethylene resin. The fluorinated urethane elastomer used in the present invention comprising the composition obtained by the above method is only required to maintain the proper hardness and excellent rubber elasticity, mechanical durability and other various properties inherent in the selected TPU. In addition, excellent surface smoothness and low dynamic friction combined with the fluororesin coating layer coated on the surface by the intermolecular plasticizing action of the fluororesin such as the above polytetrafluoroethylene, that is, good paper transportability And the abrasion resistance is remarkably improved.

[0043] Further, the invention according to the claims 15, drive
The driven roller is driven to rotate and fed between the driven roller and the driven roller.
Driven roller configured to pinch the target recording medium
Roller and the surface that contacts the recording medium is a low-friction member.
The low friction member is made of a thermoplastic elastomer and a fluorine-containing material.
Fluoro-thermoplastic composed of a composition composed mainly of silicone resin
Friction coefficient of 0.4 to 0.5 achieved by elastomer
And a fluororesin coated on the surface of the elastic part
The coefficient of friction to 0.3 or less
And a fluorine-containing resin coating layer . With this driven roller, the operation and effect of the invention relating to the recording medium feed roller can be obtained.

The invention according to claim 16 of the present application is directed to a recording head, a recording medium feed roller disposed close to an upstream side of the recording head for feeding a recording medium to the recording head side, and the recording head. And a discharge roller for discharging the recording medium to the downstream side of the recording medium, and performs recording on the recording medium by repeating the main scanning of the recording head and the sub-scanning of the recording medium by the recording medium feed roller. The recording apparatus having the configuration, wherein the paper feed drive roller includes:
A recording medium feed roller according to any one of claims 1 to 14 is provided. ADVANTAGE OF THE INVENTION According to this invention, the inconvenience which arises in the conventional driven roller is solved, and it becomes a recording device which has sufficient durability also for long-term repeated use.

[0045]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a recording medium feed roller according to an embodiment of the present invention, taken along a plane perpendicular to the axis. FIG. 2 is an enlarged sectional view of a main part of the recording medium feed roller shown in FIG. FIG. 3 is a schematic side view showing an example of an ink jet printer having the recording medium feed roller. FIG. 4 is a sectional view of the driving roller of the recording medium feed roller cut along a plane parallel to the axis, and FIG. 5 is a sectional view of the driven roller of the recording medium feed roller cut along a plane parallel to the axis. And its side view (b).

First, as shown in FIG. 3, the ink jet printer according to the present invention includes a sheet supply unit 40 for feeding print papers S set in a paper supply receiving unit such as a paper supply tray one by one toward a print area. A recording medium feed roller 30 that is arranged in the vicinity of the upstream of the print area and sends the print paper S sent from the sheet supply unit 40 to the print area while controlling the feed amount in accordance with print data transmitted from an external computer or the like; A recording head 50 and a platen unit 54 that constitute the printing area;
And a discharge roller 60 for discharging the printing paper S printed with the ink discharged from the printer to the outside of the printer. Further, a main frame 70, a first sub-frame 71, and a second sub-frame 72 for mounting each of the components are provided, and a pair of side frames (not shown) and the like are provided.

The recording medium feed roller 30 is composed of a set of a driving roller 1 that contacts the back side of the printing paper S and a driven roller 10 that contacts the recording surface side of the printing paper S. The drive roller 1 has both ends supported by the side frame, and is driven to rotate by a drive motor (not shown) as a power source. The driven roller 10 is supported in a slightly pressed state with respect to the drive roller 1 by a support mechanism described later, and rotates following the rotation of the drive roller 1. The recording medium feed roller 30 includes the drive roller 1 and the driven roller 1.
The printing paper S is sent to the recording head 50 side while the printing paper S is pressed from the front and back sides at a nip portion N (FIG. 2) of zero. The present invention is characterized by the specific structure of the set of the driving roller 1 and the driven roller 10, and a detailed description thereof will be given later, and the overall structure of the printer will be described first.

The sheet supply unit 40 is a D-shaped sheet feeding unit that feeds the printing paper S one by one toward the recording head 50 by rotation, and urges the printing paper S toward the supply roller 41. And a separation pad 42 for pressing the printing paper S between the supply roller 41 and separating the printing paper S one by one. That is, a plurality of printing papers S are set in a stacked state on the hopper constituting the paper feed receiving unit, and the printing papers S
When the printing paper S is sent out, the printing paper S is pressed by the hopper toward the supply roller 41 that rotates once, and is separated one by one by the rotating supply roller 41 and the separation pad 42. Only the sheet S is supplied to the recording medium feed roller 30.
The supplied printing paper S is guided by a lower guide 80 attached to the first sub-frame 71 and an upper guide 90 attached to the main frame 70 so as to be sent toward the recording medium feed roller 30. Has become.

The recording head 50 is mounted on a carriage 51. The carriage 51 is configured to be movable in the main scanning direction, which is a direction orthogonal to the paper surface, by the upper end 70a of the main frame 70 and the carriage guide shaft 52. An ink tank 53 such as an ink cartridge is mounted on the carriage 51. The printing operation is performed by ejecting ink from the recording head 50 while the carriage 51 moves in the main scanning direction, thereby performing printing for one scan, and each time the printing for one scan is performed, the recording medium feeding roller At 30, the printing paper S is transported by a predetermined pitch in the sub-scanning direction, which is the paper transport direction, and printing is performed by repeating these main scanning and sub-scanning operations. Numeral 54 indicates printing paper S
Is a paper position defining unit that supports and guides the lower surface of the print paper S and defines a paper gap, which is an interval between the print paper S and the recording head 50.

The discharge roller 60 is disposed close to the downstream side of the recording head 50, and is composed of a set of a drive roller 61 and a driven roller (also referred to as a star wheel) 62 urged toward the drive roller 61. This is for discharging the printing paper S printed by the recording head 50 out of the printer. The driven roller 62 is attached to the second sub-frame 72.

Next, the support structure of the driven roller 10 of the recording medium feed roller 30 will be described with reference to FIGS. 3, 6, and 7. FIG. Here, FIG. 6 is an enlarged view of the recording medium feeding roller portion of FIG. 3, and FIG. 7 is a perspective view showing a supporting structure of the driven roller.

As shown in these figures, the driven roller 1
Numeral 0 is rotatably supported by the tip of the upper guide 90. The upper guide 90 has a substantially plate shape as a whole, and has a base 91 rotatably attached to the support shaft 20 as shown in an enlarged manner in FIG. The support shaft 20 is supported from above and below by hook portions 73 and 74 bent at the lower end of the main frame 70. The left side of the support shaft 20 in FIG. 6 is in contact with the back surface (the right side surface in FIG. 6) 65 of the main frame 70. Thereby, the support shaft 20
Are arranged in parallel with the axis of the drive roller 1 of the recording medium feed roller 30.

As shown in FIG. 7, the driven roller 10
A shaft 11 and a pair of driven rollers 10 ′, 10 ′ mounted on the shaft 11 symmetrically with respect to the axial central portion 11 a of the shaft 11 and avoiding the central portion 11 a. I have. On the other hand, elongated holes 92, 92 which support both ends 11b, 11b of the shaft 11 and extend in the vertical direction (direction toward the drive roller 1) are provided at the distal end of the upper guide 90.
A pressing portion 93 that is in contact with the central portion 11a is formed. The elongated holes 92, 92 are provided at the base 91,
Are provided at the same distance from each other.

A torsion spring 100 is mounted on the support shaft 20. One end 101 of the torsion spring 100 is, as shown in FIG.
6, the other end 102 abuts against the pressing portion 93 of the upper guide 90 and urges it toward the drive roller 1.

Accordingly, the driven roller 10 is supported such that both ends 11b, 11b of the shaft 11 can move only in the direction of the drive roller 1, and the central portion 11a of the shaft 11
Only the roller is urged toward the drive roller 1 direction,
The shaft 11 is independent of the support shaft 20 and has a central portion 11a.
It is swingable (in a front view) and is pressed against the drive roller 1 along the drive roller 1. Although not shown, in the printer, a plurality of driven rollers 10 having the above-described structure are provided for the driving roller 1 in the axial direction.

Further, since the elongated holes 92, 92 supporting both ends 11b, 11b of the shaft 11 are provided at the same distance from the support shaft 20, the shaft 11 and the support shaft 20 are parallel to each other, and Since the support shaft 20 is pressed against the back surface 65 of the main frame 70 by the torsion spring 100, the parallelism between the support shaft 20 and the drive roller 1 is maintained with high accuracy. As a result, the parallelism between the shaft 11 of the driven roller 10 and the axis of the driving roller 1 is maintained with high accuracy. In particular, the shaft 11 of the driven roller 10 is
By being able to swing around the central portion 11a (in a front view) independently of 0, the parallelism in a front view is maintained with extremely high precision.

The driven roller 10 has both ends 11b, 11b of the shaft 11 supported so as to be movable only in the direction of the driving roller 1 as described above.
Since only the central portion 11a is urged in the direction of the drive roller 1, the print paper S is conveyed straight, because it is uniformly pressed against the drive roller 1.

Next, the specific structure of the driving roller 1 and the driven roller 10 constituting the recording medium feeding roller according to the present invention will be described. First, the drive roller 1 shown in FIGS.
And as shown in FIG. 4, the surface 3 of the highly rigid roller base 2
And a high friction layer 4 is integrally applied thereto. The material of the high-rigidity roller base 2 is, for example, metal, rubber, or plastic (including elastomer). In this embodiment, the high-rigidity metal is used. The high friction layer 4 is a state in which the wear-resistant particles 5 and the wear-resistant particles 5 are uniformly dispersed, and a part of the particles 5 on the tip side in the radial direction of the high-rigidity roller 2 is exposed to the surface. And an adhesion layer 6 that is firmly held by the above. That is, as shown in an enlarged cross-sectional view in FIG. 2, the high friction layer 4 has a coating in which the wear-resistant particles 5 are substantially uniformly dispersed and has a thickness smaller than the average particle size of the wear-resistant particles 5. The high-rigidity roller base 2 is integrally adhered to the surface 3 of the high-rigidity roller base 2 by the attachment layer 6. By using abrasion-resistant particles 5 having a relatively sharp and pointed shape, an uneven surface with high friction is formed.

Further, in the present embodiment, the wear-resistant particles 5
The roller is formed such that the particle diameters thereof are substantially uniform, and the roller diameter is uniform both in the longitudinal direction of the roller surface and in the circumferential direction. That is, as shown in FIG. 1 and FIG. 2, the abrasion-resistant particles 5 do not overlap in the radial direction on the roller surface 3 and almost exist in a single state, and are slightly separated in the longitudinal direction. Distributed. As described above, the wear-resistant particles 5 are arranged one by one on the roller surface 3, and the wear-resistant particles 5 are uniformly dispersed in a single-layer state. Of course, this alignment does not mean that it is strictly, but that it is almost so.

Further, the roller diameter is the surface 3 of the high rigidity roller 2.
Is larger than the diameter of the abrasion-resistant particles 5, and if there is a large variation in the particle diameter, the roller diameter itself will vary. Are evenly aligned. The present inventors have determined that the particle size of the wear-resistant particles 5 is centered around the selected particle size A [μm].
It has been confirmed that there is almost no problem in making the roller diameter uniform in the circumferential direction and the longitudinal direction if the roller diameter is set within the range of 20%.

The material of the wear-resistant particles 5 is made of a ceramic such as alumina or silicon carbide in this example. The selected particle size A is selected from the range of 20 μm to 70 μm, and is 50 μm in the present embodiment. Selective particle size A from 20 μm to 7
The selection from the range of 0 μm is such that if the particle size in this range is selected, the selected particle size A is not too large, so that the printing paper can be reliably prevented from being damaged. This is because the required friction coefficient can be easily obtained. Furthermore, the distribution density of the wear-resistant particles 5 with respect to the surface area of the high friction layer 4 is 20% to 80%.
%.

The particles using ceramic particles such as alumina and silicon carbide as the wear-resistant particles 5 have more excellent durability based on the properties of the ceramics such that they are hard and are hardly plastically deformed. However, the effect that the paper quality is not affected by the paper quality and the effect of the paper dust is further assured.

In the case where the distribution density of the wear-resistant particles 5 on the surface of the high friction layer is 20% to 80%, the distribution density is not too large, so that it is possible to surely prevent the formation of the layered state of the particles. In addition, since it is not too small, the number of contact points between the particles and the sheet S can be sufficiently ensured, and the required frictional resistance can be reliably obtained.

The material of the adhered layer 6 is for dispersing the abrasion-resistant particles 5 and firmly fixing them to the surface 3 of the roller 2 to be integrated, and can be appropriately selected from this viewpoint. In this example, an adhesive having a meaning including a paint is used. Specifically, as the adhesion layer 6, a thermosetting epoxy adhesive, a room temperature curing acrylic adhesive, a UV curing polyurethane adhesive, a two-component reactive epoxy adhesive, or the like can be used. In this embodiment, a room-temperature-curable acrylic adhesive is used.

Here, an example of a method for manufacturing the drive roller 1 shown in FIG. 4 is as follows. A room temperature curing type acrylic adhesive mixed with abrasion resistant particles 5 is used as a liquid base material, and the liquid base material is used as a roller. The adhered layer 6 in which the wear-resistant particles 5 are uniformly dispersed is formed by directly spraying the surface 3 and drying and curing the liquid base material. When the adhesive used as the adhered layer 6 is a heat-curable adhesive, the adhered layer 6 is firmly attached to the surface 3 of the high-rigidity roller 2 by performing a heat treatment (for example, at 160 ° C. for 20 minutes). Fix and integrate. Also,
When a UV-curable adhesive or the like is used, a curing process suitable for the adhesive is employed.

Next, the driven roller 10 is shown in FIGS.
As shown in FIG. 5 and the surface in contact with the printing paper S, the low friction member 13 is made of a metal,
It is provided on the outer peripheral surface of a roller base 12 made of a material such as hard plastic. And this low friction member 13
Is based on an elastic portion made of a fluorine-containing thermoplastic elastomer 14 composed of a composition mainly composed of a thermoplastic elastomer and a fluororesin, and a fluororesin coating layer 15 is formed on the surface thereof. Specifically, the fluorine-containing thermoplastic elastomer 14 is formed of a composition mainly composed of a thermoplastic polyurethane elastomer (TPU) and a fluororesin. Further, the fluororesin coat layer 15 is formed of a fluororesin made of polytetrafluoroethylene.

That is, in the present embodiment, the material of the fluorine-containing thermoplastic elastomer 14 constituting the elastic portion which is the base of the low friction member 13 formed on the roller base 12 is hardness (JIS, K-7311). JI by
(S, A hardness) in the range of about 60 ° to 95 ° are selected and used.

In particular, among these, an elastomer composition comprising TPU as a main component and blended with a fluororesin such as polytetrafluoroethylene is generally used, and the fluororesin coating layer 15 is further formed on the surface thereof. 5μ
By coating with a thickness of m to 20 μm, a driven roller having various functions such as moderate elasticity (hardness), rebound resilience, and low friction on the surface can be obtained. The wear resistance is improved. The fluororesin coating layer is coated as a single layer (up to a thickness of about 10 μm) by one application or two layers (at a thickness of 10 μm or more) by two applications.

Further, as a preferable composition of the fluorine-containing thermoplastic elastomer 14 constituting the elastic part, the hardness is about 60%.
And 95 to 90% by weight of TPU and 10 to 15% by weight of polytetrafluoroethylene, in particular, a composition having a fluorine content of about 10%. The composition may contain small amounts of pigments, heat stabilizers, flame retardants, weathering agents, and the like.

As the TPU, a commercially available elastomer known per se and having an appropriate hardness can be selected and used. For example, a polyether-based TP comprising a polycondensate of a diisocyanate such as tolylene diisocyanate and a polyol such as diethylene glycol, polyethylene glycol and polypropylene glycol.
It is more preferable to use U in terms of hydrolysis resistance and germ resistance (deterioration resistance due to mold and the like) in addition to low friction properties.

In particular, 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 a diisocyanate
It is preferable to use

The fluorine-based resin blended as a small component with respect to the TPU includes, in addition to the polytetrafluoroethylene resin (PTFE), ethylene trifluoride chloride resin (PCTFE) and hexafluoroethylene propylene resin. (PFEP), vinyl fluoride resin (PVF), vinylidene fluoride resin (PVDF), etc., among which polytetrafluoroethylene resin is particularly preferred.

The method of preparing the composition is not particularly limited to a specific one, but may be a method known per se,
For example, a melt blending method or the like can be used.

The fluororesin coating layer 15 is formed of the polytetrafluoroethylene resin (PTFE).
In addition, ethylene trifluoride chloride resin (PCTFE), hexafluoroethylene propylene resin (PFEP), vinyl fluoride resin (PVF), vinylidene fluoride resin (PVD
F) and the like.

In the present invention, the low friction member 1 comprising the fluorine-containing thermoplastic elastomer 14 constituting the elastic portion and the fluororesin coating layer 15 coated on the surface thereof.
3 is steel such as iron, steel and stainless steel, copper alloy such as brass and gunmetal, light metal such as aluminum and aluminum alloy, or hard such as polyoxymethylene resin, polycarbonate resin, polyester resin and polyamide resin. For example, it is provided on the peripheral surface of the roller base 2 made of a material such as engineering plastic and having the shape shown in FIG.

As a method for forming the low-friction member 13 composed of the fluorine-containing thermoplastic elastomer 14 and the fluororesin coating layer 15, the low-friction member 13 is formed by injection molding or extrusion molding, and the surface thereof is further coated with a fluororesin. Coating the coating layer with a single layer (up to a thickness of about 10 μm) or two layers (at a thickness of 10 μm or more),
A method of attaching it to the outer peripheral surface of the roller base 12 is exemplified.

The thickness of the elastic portion made of the fluorine-containing thermoplastic elastomer 14 and the low-friction member 13 made of the fluororesin coating layer 15 are appropriately set according to the size and usage of the driven roller. Is set to a layer thickness of about 1 / 2.5 to 1/10 with respect to the diameter of This makes it possible to easily bring the structural balance into a good state.

The surface of the elastic portion formed of the above-mentioned fluorine-containing thermoplastic elastomer 14 thus formed requires a special surface treatment such as a surface coating process, to the extent that a slight surface smoothing treatment is performed as required. In this case, the driven roller 10 is formed to such an extent that the paper conveyance performance suitable for the driven roller 10 is exhibited. In the present embodiment, the surface of the fluorine-containing thermoplastic elastomer 14 in such a surface state is coated with a fluororesin coating layer 15.

Next, the operation of the recording medium feed roller according to the above embodiment will be described. According to the present embodiment, the high friction layer 4 of the drive roller 1 has the abrasion-resistant particles 5 substantially uniformly dispersed in the adhered layer 6 and the dispersed particles 5 apply to the printing paper S. Since the contact at an acute angle is configured, high frictional resistance can be stably exhibited not only on plain paper and the like but also on a smooth sheet such as a glossy film. Therefore, the transport accuracy is not affected by the paper quality,
stable. Further, since the paper powder hardly adheres to the particle portion and peels off immediately if it arrives, the frictional resistance does not decrease over the long term, and the conveyance accuracy can be maintained high.

The driven roller 10 used in combination with the driving roller 1 having the above-mentioned structure has a low friction member 13 on the surface that comes into contact with the printing paper S, and the low friction member 1
3 is based on a fluorinated thermoplastic elastomer 14 composed of a composition mainly composed of a thermoplastic elastomer and a fluororesin, and a fluororesin coating layer 15 is formed on the surface thereof to a thickness of 5 μm.
It is formed with a thickness of ２０20 μm. The low friction member 1
3 has a surface friction coefficient of 0.25 or less, and the fluorine-containing thermoplastic elastomer 14 forming the base thereof also has a surface friction coefficient of 0.4 to 0.5. Since the surface of the fluorine-containing thermoplastic elastomer 14 having a relatively low friction coefficient is further coated with the fluororesin coating layer 15 having a low friction coefficient, the driven roller 10 has a surface friction coefficient of 0.3 or less. Accordingly, the requirement for exhibiting the function of the low friction coefficient (first function) can be sufficiently satisfied.

The low-friction member 13 does not have a structure in which the surface of a rubber elastic roller made of ordinary rubber such as chlorinated polyethylene is covered with a fluorine coat layer as in the related art.
The surface is coated with a fluorine resin coat layer 15 based on the fluorine-containing thermoplastic elastomer 14 as a base. The low friction member 13 composed of the fluorinated thermoplastic elastomer 14 and the fluororesin coating layer 15 is:
A low friction state of the surface could be maintained for a longer period than a low friction member composed of a conventional rubber such as a conventional chlorinated polyethylene and a fluororesin coating layer. Therefore, there is little fear that the fluororesin coat layer is worn due to repeated use for a long period of time as in the related art, and the state of a low friction coefficient cannot be maintained. Moreover, the low friction member 13 is made of the fluorine-containing thermoplastic elastomer 14 having a relatively low friction coefficient (0.4 to 0.5) even when the surface of the fluororesin coating layer 15 is slightly worn. The state of the low friction coefficient is maintained within a range that does not cause any problem even if it is slightly reduced. Accordingly, the second function of maintaining the low friction coefficient state can be exhibited.

Further, the elasticity of the elastic portion made of the fluorine-containing thermoplastic elastomer 14 forming the base of the low-friction member 13 has the same hardness (JIS, K-731) as ordinary rubber.
1) (JIS, A hardness), 60 ° to 95 °
, The moderate elasticity (third function) required for the surface of the driven roller 10 can be easily provided. Although the elasticity is strictly reduced by coating the surface of the elastic portion made of the fluorine-containing elastomer 14 with the fluororesin coating layer 15, the thickness of the coating layer 15 is set so that the elasticity reduction does not substantially cause a problem ( By setting the thickness to 5 [mu] m to 20 [mu] m, the problem of a decrease in elasticity due to the coat layer can be prevented.

Further, since the fluorine-containing thermoplastic elastomer 14 hardly contains a compound such as a plasticizer, the compound does not elute on the surface over time. Therefore, if the fluororesin coating layer 15 on the surface is
When the compound comes into contact with the adhesive mainly composed of the acrylic resin or the like present on the surface of the opposing drive roller 1 even when it is worn, the acrylic resin dissolves by chemically reacting with the acrylic resin or the like. The problem itself does not arise.

[0084]

EXAMPLES Example 1 Elastomer composition of polyether-based TPU: polytetrafluoroethylene resin = 9: 1 by weight (hardness: J
IS, A85 °, containing a small amount of white inorganic pigment), and by using this composition, an elastic part made of the cylindrical fluorine-containing thermoplastic elastomer 14 shown in FIG. 5 is molded. The roller base 12 made of a polyoxymethylene resin having the shape shown in FIG.
mm), and the surface of the fluorine-containing thermoplastic elastomer 14 is coated with a fluororesin coating layer 15 to obtain a driven roller of the present invention (Example 1).
Was.

Comparative Example 1 Separately, the same substrate as the roller substrate 2 made of polyoxymethylene resin used in Example 1 was used.
On this peripheral surface, a surface fluororesin coating was applied (tetrafluoroethylene resin coating thickness of about 20).
μm) A conventional driven roller equipped with a synthetic rubber member having a thickness of 1 mm was prepared (Comparative Example 1).

The roller of Example 1 was 0.25 and the roller of Comparative Example 1 was 0.2 when the coefficient of rolling friction of the driven rollers on the front surface of the A4 copy paper was measured.

Next, these rollers are mounted as driven rollers for transporting printing paper of a printer (MJ-830C, PM-700C type manufactured by Epson Corporation), and A4-size copy paper is loaded and transported to each printer. Was. The drive roller 1, which is paired with these driven rollers, has a high friction layer in which the above-mentioned ceramic particles are uniformly dispersed. The results are as follows using the driven roller of Comparative Example 1.
During the conveyance of 10,000 sheets, the coated surface of the roller was partially peeled off due to abrasion, and the rubber surface was exposed. As a result, the conveyance could not be carried out smoothly, and the copy paper surface was contaminated with extraneous matter. On the other hand, the apparatus equipped with the driven roller of Example 1 had no trouble in the operation even when the sheet was transported to 75,000 sheets or more, and no stain was observed on the surface of the sheet. The friction coefficient of the surface of the driven roller 10 of Example 1 was measured at the stage when 75,000 sheets were conveyed. As a result, the state of the initial low friction coefficient (0.25) was maintained.

[Example 2] Here, the driven roller 10 having the low friction member 13 in which the fluororesin coating layer 15 is provided on the surface of the fluorine-containing thermoplastic elastomer 14 is applied to the surface of chlorinated polyethylene which is a normal rubber. Test results showing that an initial low friction state can be maintained for a long period of time compared to a driven roller having a low friction member provided with a fluororesin coating layer will be described. (1) Test method Ball-on-disk (BOD) method Test conditions Load: 500 gf Rotating circle diameter: diameter (φ) 60 mm Rotation speed: 200 rpm Slider material: steel ball (diameter 10 mm) (2) Test sample 1 . Chlorinated polyethylene rubber + fluororesin coating layer (5
1. One layer at μm) Chlorinated polyethylene rubber + fluororesin coating layer (1
(2 layers at 5 μm) 3. Fluorine-containing thermoplastic elastomer + fluororesin coating layer (one layer at 5 μm) Fluorine-containing thermoplastic elastomer + fluororesin coating layer (2 layers at 15 μm) (3) Test result As shown in FIG. 8, the test sample 1 has a life of about 200,000 revolutions, and the test sample 2 has the test sample 2 as shown in FIG. The test sample 3 according to the present invention has a life of 5 million rotations as shown in FIG. 10, while the test sample 4 has a life of 6.35 million rotations as shown in FIG. is there.
Therefore, it can be seen that the life of the present invention is increased by about 10 times. This is the set number of sheets passed by the printer, 75,
The life is long enough to clear 000 sheets.

The coefficient of friction of the chlorinated polyethylene rubber is about 1.0, and the coefficient of friction of the fluorine-containing urethane elastomer itself is 0.65. 8 to 11, the friction coefficient of each of the test samples 1 to 4 is initially 0.4 to 0.4.
0.5 is the value of O. It is a friction count value in the D method. These values indicate that the coefficient of friction as a driven roller for a recording medium when mounted on an actual printer is equivalent to 0.3 or less.

According to the present invention, in a recording medium feeding roller composed of a set of a driving roller and a driven roller, the driving roller has a high friction coefficient by dispersing wear-resistant particles on its surface. Even if it is a driven roller, the driven roller can fully demonstrate each function such as low friction coefficient, persistence of low friction coefficient state, moderate elasticity, prevention of compound dissolution even after repeated use for a long period of time. can do.

According to the driven roller according to the present invention, the operation and effect of the recording medium feed roller can be reliably obtained. Further, according to the recording apparatus of the present invention, it is possible to eliminate the inconvenience caused by the conventional driven roller, to have sufficient durability for long-term repeated use, and to prevent the deterioration of the recording quality for a long time. Can be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a recording medium feed roller according to an embodiment of the present invention, taken along a plane perpendicular to an axis.

FIG. 2 is an enlarged sectional view of a main part of the recording medium feeding roller shown in FIG.

FIG. 3 is a schematic side view showing an example of an ink jet printer including the recording medium feed roller.

FIG. 4 is a cross-sectional view of a driving roller of the recording medium feeding roller cut along a plane parallel to an axis.

FIG. 5A is a cross-sectional view of a driven roller of the recording medium feed roller, taken along a plane parallel to an axis, and FIG.
It is.

FIG. 6 is an enlarged view of a recording medium feeding roller portion of FIG. 3;

FIG. 7 is a perspective view showing a support structure of the driven roller.

FIG. 8 shows the change in the durability (time) of the friction coefficient of the conventional driven roller. O. It is a figure showing the result of having tested by the D method.

FIG. 9 shows the durability (time) change of the friction coefficient of another conventional driven roller. O. It is a figure showing the result of having tested by the D method.

FIG. 10 shows the change in the durability (time) of the friction coefficient of the driven roller according to the present invention. O. It is a figure showing the result of having tested by the D method.

FIG. 11 shows the change in the durability (time) of the friction coefficient of another driven roller according to the present invention. O. It is a figure showing the result of having tested by the D method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive roller 2 High rigidity roller 3 Roller surface 4 High friction layer 5 Abrasion resistant particle 6 Adhered layer 10 Follower roller 12 Elastic roller 13 Low friction member 14 Thermoplastic elastomer (elastic part) 15 Fluororesin coat layer S Printing paper

Claims (16)

(57) [Claims] An image forming apparatus includes a pair of a driving roller which is disposed close to an upstream side of a recording head and contacts a back side of a recording medium, and a driven roller which contacts a recording surface side of the recording medium. A recording medium feed roller for feeding the recording medium to the recording head side while nipping the recording medium from the front and back, wherein the driving roller has a high friction layer integrally attached to a surface of a highly rigid roller base. The high-friction layer is formed of abrasion-resistant particles, and the abrasion-resistant particles are uniformly dispersed, and the particles are firmly formed in such a manner that a part of the particles at the tip side in the radial direction of the high-rigidity roller is exposed to the surface. The driven roller has a surface in contact with a recording medium made of a low friction member, and the low friction member is made of a composition mainly composed of a thermoplastic elastomer and a fluororesin. Fluorine-containing thermoplastic elastomer An elastic part having a friction coefficient of 0.4 to 0.5 by a tomer, and coating the surface of the elastic part with a fluororesin.
And a fluorine resin coating layer having a friction coefficient of 0.3 or less . 2. The recording medium feeding roller according to claim 1, wherein the fluorine-containing thermoplastic elastomer is mainly composed of a thermoplastic polyurethane elastomer and a fluorine resin. 3. The recording medium feeding roller according to claim 1, wherein the thickness of the fluororesin coating layer is 5 μm to 20 μm. 4. The wear-resistant particles according to claim 1, wherein the wear-resistant particles are uniformly dispersed in a single-layer state on a roller surface, and the adhered layer is an average particle of the wear-resistant particles. A recording medium feed roller formed to have a thickness smaller than a diameter. 5. The recording medium feed roller according to claim 1, wherein the wear-resistant particles are made of a ceramic such as alumina or silicon carbide. 6. The recording medium feed roller according to claim 1, wherein the adhered layer is made of an acrylic adhesive. 7. The high friction layer according to claim 1, wherein the high friction layer sprays a liquid base material, into which the wear-resistant particles are uniformly mixed, onto a surface of the high rigidity roller. A recording medium feeding roller, wherein the base material is subjected to a curing treatment to form the adhered layer. 8. The method according to claim 1, wherein the size of the wear-resistant particles is 20 μm in average particle size.
A recording medium feed roller having a diameter of from 70 to 70 μm. 9. The particle according to claim 8, wherein the particle size of the wear-resistant particles dispersed in the high friction layer is 20% or less.
A recording medium feeding roller characterized in that the particle size is adjusted within a range of ± 20% around a particle size A [μm] selected from a range of μm to 70 μm. 10. The recording medium feed roller according to claim 1, wherein the distribution density of the wear-resistant particles with respect to the area of the surface of the high friction layer is 20% to 80%. . 11. The fluorinated thermoplastic elastomer of the driven roller according to claim 1, wherein the proportion of the main component of the fluorinated thermoplastic elastomer is 85 to 90% by weight of the thermoplastic polyurethane elastomer component. A recording medium feeding roller, wherein the content of the tetrafluoroethylene component is 10 to 15% by weight. 12. The thermoplastic polyurethane elastomer according to claim 2 , wherein the thermoplastic polyurethane elastomer is a diisocyanate,
A recording medium feeding roller comprising a polyol-based multi-block polymer obtained by polycondensing a high molecular weight polyol and a low molecular weight polyol. 13. The recording apparatus according to claim 1, wherein said low-friction member is provided with a thickness of 1 / 2.5 to 1/10 based on a diameter of a driven roller. Media feed roller. 14. The hardness according to claim 1, wherein a hardness (JIS, A hardness according to JIS, K-7311) of the elastic portion made of the fluorine-containing thermoplastic elastomer is in a range of 60 ° to 95 °. A recording medium feed roller, characterized in that: 15.The drive roller is driven to rotate and the drive
This pinches the recording medium to be fed between the moving rollers.
A driven roller formed like this, The surface in contact with the recording medium is made of a low friction member, The low friction member comprises a thermoplastic elastomer and a fluororesin.
Fluorine-containing thermoplastic elast consisting of composition as main component
Elasticity of 0.4 to 0.5 with friction coefficient
Department and Coating the surface of the elastic part with a fluororesin
Therefore, a fluororesin coating with a friction coefficient of 0.3 or less
Layer and Characterized by consisting of Driven roller. 16. A recording head, a recording medium feeding roller disposed close to the upstream side of the recording head for feeding a recording medium to the recording head side, and a recording medium disposed close to the downstream side of the recording head to feed the recording medium. A discharge roller for discharging downstream, and a recording apparatus configured to perform recording on the recording medium by repeating a main scan of the recording head and a sub-scan of the recording medium by the recording medium feed roller, wherein the recording is performed. A recording apparatus, wherein the medium feeding roller is configured by the recording medium feeding roller according to any one of claims 1 to 14.