JP2003118873A - Manufacturing method for paper conveying roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently and economically manufacturing a paper conveying roller the friction resistance on the surface of which is constant and sufficient. SOLUTION: The manufacturing method of the paper conveying roller comprises a step for bonding a powder coating and powder for protrusions in which powder coating and powder for protrusions are bonded to the surface of a core material to form a powder coating and powder for protrusions bonding core material 41, and another step for heating and solidification in which the powder coating and powder for protrusions bonding core material 41 is heated to harden or melt and solidify the powder coating. Thus the core material is coated with a resin layer comprised of powder coating which is hardened or melted and solidified, and the powder for protrusions is embedded in the resin layer in the state of partly exposed. During the heating and solidification step, a surface pressing step is performed in which the surface of the powder coating and power for protrusions bonding core material 41 is pressed to squeeze the powder for protrusions into the powder coating or the melt of the powder coating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sheet carrying roller.

[0002]

2. Description of the Related Art Conventionally, a paper carrying roller used in a printer, a facsimile machine or the like is required to have a very accurate paper carrying performance in order to realize a precise print image quality.
Therefore, in order to increase the coefficient of friction between the paper and the contact surface on the roller surface, particles in which protrusion particles such as ceramics or metal are fixed on the surface of the core material by a binder made of resinous paint are often used. There is.

Conventionally, as a method of manufacturing a sheet conveying roller having the projection particles fixed on the surface thereof, the projection particles such as ceramics or metal and a coating material as a binder are mixed on the surface of a core material to form the projection particles. Spray coating is performed by spraying a mixture of particles and paint onto the core material with a spray gun or other sprayer, then baking in a heat drying furnace to melt the paint, and then solidifying by cooling to solidify the projection particles on the surface of the core material. There is a way to do it.

However, in the method using the atomizer such as the spray gun, the mixture of the particles for projection and the paint sprayed on the core material by the atomizer is mixed with the particles for the projection in the paint tank, the nozzle for spraying or the like. Since unevenness is likely to occur, there is a problem that the amount of paint and particles for protrusion attached to the surface of the core material becomes non-uniform, and it is difficult to obtain a paper transport roller of constant quality. Furthermore, since the particles for protrusion are covered with the solidified resin on the surface of the core material, there is a problem that the frictional resistance on the surface of the paper transport roller is not sufficient.

Further, the coating material is sprayed on the core material and then melted, and the particles for protrusion are attached before the molten resin produced thereby is solidified, and the particles for protrusion are fixed on the surface of the core material by solidification of the molten resin. A method of manufacturing a sheet conveying roller has also been proposed. However, according to this method, the particles for protrusions attached to the surface of the molten resin are freely embedded in the molten resin due to their own weight or the like until the molten resin is completely solidified. And the variation of weight. Therefore, as shown in FIG. 6, the obtained paper transport roller 70 has the projection particles 7 from the surface of the solidified resin layer 72.
There is a problem in that it is difficult to obtain a uniform degree of exposure of No. 3 and it is difficult to obtain a sheet conveying roller with a constant sheet conveying property. Moreover, the maximum size of the product outer diameter standard is set in advance for the paper transport roller according to the printer used, etc., and the size of the paper outside the maximum size of the product outer diameter standard is set. The transport roller becomes a defective product at the time of product inspection, which causes a rise in manufacturing cost.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a method for efficiently and economically manufacturing a sheet conveying roller having a constant surface frictional resistance and sufficient. Is.

[0007]

According to a first aspect of the present invention, a powder coating material and a projection material for forming a powder coating material and a projection particle-attached core material by adhering powder coating material and projection particles to the surface of a core material. The core material is hardened or melted and solidified by the particle adhering step and the heating and solidifying step of heating the powder coating material and the particle-adhering core material for projections to cure the powder coating material or to solidify it after melting. In the method for producing a paper carrying roller, which is covered with a resin layer made of a material, and is embedded in the resin layer with the projection particles partially exposed, in the middle of the heating and solidifying step, the powder under heating The present invention is characterized by performing a surface pressing step of pressing the surface of the coating material and the particle-attached core material for projections to push the projection particles into the powder coating material or the melt of the powder coating material.

According to a second aspect of the present invention, in the first aspect, in the step of attaching the powder coating material and the projection particles, the powder coating material is attached to the surface of the core material to form the powder coating material attached core material. And a step of adhering particles for protrusions to the surface of the core material to which the powder coating material is attached to form the powder coating material and the core material to which the particle particles for protrusions are attached.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the powder coating material is applied to the rotatable pressing roller whose rotation axis is parallel to the powder coating material and the particle-adhering core material for projection during the surface pressing step. And pushing the particles for protrusions into the powder coating material or a melt of the powder coating material by rotating the powder coating material and the particle attachment core material for protrusions at least once while contacting the particle attachment core material for protrusions. Is characterized by.

According to a fourth aspect of the present invention, in the third aspect, the pressing rotary members are two parallel to each other and are rotatable in the same direction, and the powder coating material and the projection are provided between the two pressing rotary members. By sandwiching the particle-attached core material and rotating the powder coating material and the particle-attached core material for protrusions at least once while contacting the two pressing rotating bodies, the particles for protrusions are powdered or of the powder coating material. It is characterized by being pushed into the melt.

According to a fifth aspect of the present invention, in any one of the third and fourth aspects, one of the powder coating material, the particle-attached core material for protrusions, and the pressing rotator is driven to rotate in one direction.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a partially enlarged sectional view of a sheet conveying roller according to an embodiment of the present invention, FIG. 2 is a schematic diagram of an electric field fluidized powder coating apparatus, and FIG. 3 is an example of an apparatus used in a surface pressing step. 5 is a schematic top view, FIG. 4 is a schematic top view showing another embodiment of the apparatus used in the surface pressing step, and FIG.
FIG. 4 is a schematic diagram showing the measurement of static friction coefficient.

A sheet conveying roller 10 shown in a partially enlarged sectional view of FIG. 1 is manufactured by a manufacturing method according to an embodiment of the present invention, and is formed on a core material 11 and a surface of the core material 11. The resin layer 14 and the projection particles 13 embedded in the resin layer 14 and partially exposed. The broken line S in the figure represents the maximum value of the product outer diameter dimension standard.

The core material 11 has a required durability for mounting on a printer or the like, and for transporting a sheet. Further, as described later, when the sheet transport roller 10 is manufactured, the entire surface of the core material 11 is powdered. There is no particular limitation as long as it can be charged to the extent that the body paint 12 and the projection particles 13 can be attached. Examples of the core material 11 include those made of metal or various alloys such as aluminum alloy and stainless steel, those plated on free-cutting steel, those plated on a resin base to give conductivity, and the like. Those having electrical conductivity are preferred. Depending on the core material, it is possible to install a primer layer for facilitating plating and to form a foamed resin layer for improving flexibility. The core material 11 may be a solid body or a hollow body, and the core material 11 in the example of FIG. 1 is a hollow body.

The resin layer 14 is one in which the powder coating material 12 adhered in a layer form on the surface of the core material 11 by an electric field fluidized powder coating device to be described later is melted in a subsequent heating and solidifying step and solidified by cooling or the like. Yes, it functions as a binder for fixing the particles 13 for the protrusions. The average particle size of the powder coating material 12 used to form the resin layer 14 is 5 to 250.
μm, particularly 20 to 50 μm, and further preferably 30 to 50 μm. If the average particle size is less than 5 μm,
Problems tend to occur in fixing the projection particles 13. When the average particle size is 250 μm or more, the resin layer 1
4, the projection particles 13 are buried too much, the projection particles 13 do not sufficiently project on the surface of the resin layer 14, and the paper transport performance may be deteriorated.

The powder coating material 12 is mainly composed of a thermosetting resin which is hardened by heating and solidified, or a thermoplastic resin which is melted by heating and then solidified by cooling. Examples of the thermosetting resin include epoxy resin, unsaturated polyester resin, phenol resin, silicone resin and melamine resin, and glycidyl ether type epoxy resin is particularly preferable. Examples of the thermoplastic resin include saturated polyester resin, polyethylene, polypropylene, vinyl chloride, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), and the like.
Particularly preferred is saturated polyester resin. The powder coating material may be prepared from only one type of thermosetting resin and thermoplastic resin or from a plurality of types.

Further, the powder coating material 12 is preferably composed mainly of an epoxy resin powder and a carboxyl group-containing polyester resin powder which is a curing material, and the epoxy resin powder is a glycidyl ether type epoxy resin powder. Especially desirable. When this powder coating material is used, it is easy to make the thickness of the resin layer uniform and the fixing property of the particles for protrusions is excellent.

The particles 13 for the protrusions are used to improve the frictional resistance of the surface of the paper transporting roller 10 to an appropriate degree so as to exhibit excellent paper transportability, and are fixed to the resin layer 14 and partly. Are exposed from the surface of the resin layer 14. The particles 13 for the protrusions are adhered onto the powder coating material on the surface of the core material 11 by using an electric field fluidized powder coating device, which will be described later, at the time of manufacturing the paper transport roller 10, and then by the subsequent heat solidification step. The resin layer 14 is strongly fixed in a partially exposed state on the solidified resin layer 14. The average particle diameter of the particles 13 for protrusions is preferably 5 to 250 μm, particularly 10 to 120 μm, and further preferably 30 to 50 μm. Average particle size is 5
When it is less than μm, the particles 13 for protrusions are not sufficiently exposed from the surface of the resin layer 14, while when the average particle diameter is 250 μm or more, it becomes difficult to fix and hold the particles 13 for protrusions on the resin layer 14, May fall off.

As the particles 13 for the projection, alumina, silicon carbide, iron oxide, chromium oxide, cesium oxide,
Titanium oxide, amorphous silica powder, mullite, carbide, nickel powder, iron powder and the like are used. These projection particles 13 can be used alone or in combination of two or more kinds. In the case of ceramic particles such as alumina, those having a particle diameter of 15 to 80 μm are preferable, and in the case of amorphous silica particles or nickel particles, the particle diameter is 3
It is preferably 0 to 110 μm.

The preferable range of the average particle size of the powder coating material 12 and the particles for projection 13 is as described above, but more preferably, the average particle diameter of the powder coating material with respect to the average particle size of the particles for projection 13 is preferable. The ratio of 0.3 to 0.7, especially 0.4 to 0.5
Is. When the ratio of the average particle diameter is less than 0.3, the particles 13 for protrusion are not sufficiently fixed to the resin layer 14 and easily fall off. On the other hand, when it exceeds 0.7, the projection particles 13 are embedded in the resin layer 14, and sufficient projections are not formed on the surface of the resin layer 14, and reliable paper transport performance is likely to be impaired.

Next, a method of manufacturing the carrying roller of the present invention will be described by taking the case of the paper carrying roller 10 as an example. The manufacturing method of the transport roller according to the present invention includes a powder coating material attaching and projection particle attaching step, a heating and solidifying step,
The surface pressing step performed during the heating and solidifying step.

In this example, the powder coating material attaching and projection particle attaching steps further include a powder coating attaching step and a projection particle attaching step. In the powder coating material applying step, the powder coating material 12 is formed by a known electric field fluidized powder coating method.
Are adhered to the surface of the core material 11 in layers to form a powder coating material-adhered core material. The electric field fluidized powder coating method is performed by a known electric field fluidized powder coating apparatus 20 as schematically shown in FIG. 2, and has higher adhesion (painting) accuracy than a spray coating method using a normal spray gun. Moreover, it is a painting method that allows stable painting.

In the powder coating coating step, first,
One end side of the core material 11 is fixed to the holding shaft 22, and the core material 11 is hung in the flow tank 21 of the electric field fluidized powder coating apparatus 20 by the holding shaft 22 with the core material 11 facing downward. The holding shaft 22 has a hole 2 formed in the upper lid 21a of the flow tank 21.
A rotation motor 29 is connected to an end portion that is vertically inserted through 1b and projects outward from the upper lid 21a so that the rotation motor 29 can rotate together with the core 11. In addition, in the flow tank 21, blow pipes 27, 27 facing each other at a required interval so as to sandwich the suspended core material 11 are blown with air over at least the entire length of the core material 11. And the core material 1 of the spray pipes 27, 27.
A charging needle 28 is erected on one side surface and is connected to and applied with an application device (not shown).

Next, the blowing pipe 2 is added to the flow tank 21.
Air is blown from the blower 23 via 4, 25, and an air flow is generated in the flow tank 21 by the air. Due to the generation of this air flow, the powder coating material 12 accumulated up to that time is wound up on the bottom portion 26 in the fluidized tank 21, and
A state called “cloud” in which the powder coating material 12 is uniformly dispersed in the inside 1 is created. At that time, the flow tank 21 is mounted on the rocking plate V connected to the rocking motor 31,
By the swing of the swing plate V by the swing motor 31,
The flow tank 21 itself vibrates, and it is easy for the powder coating material 12 to be rolled up and "clouded".

The rolled-up powder coating 12
Is a blowing pipe 27 disposed on both sides of the core material 11,
The powder coating material 12 is charged by passing in the vicinity of a charging needle 28 provided upright on or in contact with the charging needle 28, and the charged powder coating material 12 is moved to the vicinity of the surface of the core material 11 by the air ejected from the spray pipes 27, 27. , Is attached to the surface of the core material 11 by electrostatic force. At that time, the core material 11 is being rotated by the rotation motor 29, and the powder coating material 12 is
The powder coating adhered core material is formed by adhering to the surface in a uniform layer. Reference numeral 30 is a dust collector.

In the step of attaching particles for protrusions, the particles 13 for protrusions are attached to the powder coating material 12 of the core material for attaching powder coating material to form the powder coating material and the core material for attaching particles for protrusions. It should be noted that the work in the step of attaching particles for protrusions only involves changing the powder coating material 12 to particles 13 for protrusions using the electric field fluidized powder coating device 20 in the step of attaching powder coating material, and the description is complicated. Detailed description is omitted to avoid

The powder coating material 12 used for attachment to the core material 11 or the projection particles 13 used for attachment to the surface of the powder coating material 12 as described above has a mass per unit volume. The bulk density expressed as
It is desirable that the amount is 10 to 10 g / cm ³ , particularly 0.3 to 3.0 g / cm ³ , and further 0.7 to 1.5 g / cm ³ . If the bulk density is less than 0.1 g / cm ^3, not obtained both sufficient frictional resistance when sufficient resin layer 14 is not formed on the core material 11 surface, 10 g / cm ³ whereas
When it exceeds, it becomes difficult to form a uniform cloud in the fluidized tank 21, and the powder coating material 12 adheres to the core material 11 and the particles 13 for protrusion on the powder coating material 12 adhered to the core material 11. Is likely to be unevenly attached.

In the heating and solidifying step, the powder coating material 12 adhered to the core material 11 is heated to be cured when the powder coating material 12 is a thermosetting resin, and melted when it is a thermoplastic resin. Then, it is solidified by subsequent cooling, and a surface pressing step is performed during the heating.

In this embodiment, the heating and solidifying step is further performed by a first heating step and a second heating step. The first
In the heating step, the powder coating material and the particle-attached core material for protrusions are subjected to high-frequency induction heating by a known high-frequency generator such as a high-frequency induction coil or a magnetron. By performing this high-frequency induction heating, it is possible to directly raise the temperature of the entire core material 11 when the core material 11 is entirely metal and the metal layer on the surface when the surface of the core material 11 is metal. The powder coating material 12 adhering to the surface of the heated core material 11 can be efficiently heated from the core material 11 side. In particular,
The inside of the core material 11 surface side of the powder coating material 12 adhered in layers on the surface of the core material 11 is a portion which is hard to reach and is difficult to heat even if it is heated from the outside by an electric heater or the like. By heating, it can be sufficiently heated.

In the subsequent second heating step, the powder coating material 12 heated from the inside on the core material 11 side by the first heating step.
Is heated from the outside to uniformly heat the entire powder coating material 12. By the second heating step, the powder coating material 12 starts a curing reaction in the case of a thermosetting resin, and melts in the case of a thermoplastic resin. Incidentally, in the first heating step, a part of the powder coating material 12 may start a curing reaction or may start melting. This second
The heating from the outside in the heating process is performed by a quartz tube heater,
It is performed by a known far infrared ray irradiation device such as a carbon heater.

By using the two different heating methods as described above, the powder coating material 12 adhering in layers on the surface of the core material 11 can be heated uniformly and in a short time. The manufacturing time of the roller 10 can be shortened.

In the surface pressing step, the powder is powdered during the curing reaction or before solidification of the powder coating material in a molten state, that is, during heating of the powder coating material 12, in this example, during the second heating step (far infrared heating). The surface of the coating material and the particle-attached core material for protrusions is pressed to make the protrusion amount of the protrusion particles 13 protruding from the surface of the powder coating material 12 constant.

FIG. 3 shows an outline of an example of an apparatus used in the surface pressing step. In the illustrated example, the powder coating material and the particle-attached core material 41 for protrusions, which are being subjected to far-infrared ray heating by the far-infrared ray irradiation device RH in the second heating step HB, are described as follows. 41 and the rotating shafts 42a and 43a are parallel to each other and sandwiched between two rotatable pressing rotors 42 and 43,
The powder particles and the particle-attached core material for protrusions 41 are rotated at least one time while the surface of the powder-coated material and the particle-attached core material for protrusions 41 are brought into contact with the surface of the powder coating material 43, so that the particles for protrusion 13 are powder-coated. 12 or the required amount is pushed into the melt of the powder coating material 12 to make the protrusion amount constant.

The pressing rotators 42 and 43 are rotatable in the same direction, and the surface distance between the pressing rotators 42 and 43 is substantially equal to the outer diameter of the target sheet conveying roller 10. To be done. Further, in this example, one pressing rotary member 42 is rotationally driven in one direction by a rotary motor (not shown), and the powder coating material and the protrusion particle-attached core material 41 are attached to the rotationally driven pressing rotary member 42. When the powder coating material and the protrusion-attached particle adhering core material 41 rotate, the other freely rotatable pressing rotor 43 that comes into contact with the rotating powder coating material and the protrusion-attached particle adhered core material 41. Is designed to rotate.

Further, the pressing rotary members 42 and 43 shown in FIG.
Is composed of a rotating roller, and the pressing rotating body 5 shown in FIG.
Like Nos. 2 and 53, the rotary shaft 54 may be parallel to the powder coating material and the particle-attached core material 41 for protrusions, and the two belts may be opposed to each other.

The pressing rotating bodies 42, 43, 52, 53
It is preferable that at least the surface is made of a fluororesin so that the powder coating material 12 does not adhere to the powder coating material 12 when it is cured or melted. The two pressing rotary members 42 (5
2) and 43 (53) are both driven to rotate in the same direction, or both pressing rotors 42 (52) and 43
(53) is allowed to rotate freely, and the pressing body 42 for pressing both the
The powder coating and the particle-attached core material 41 for protrusions that come into contact with (52) and 43 (53) may be rotated at least once by a rotation motor. Further, the two pressing rotors 42
Instead of (52) and 43 (53), one pressing rotating body comes into contact with the surface of the powder coating material and the particle-adhering core material 41 for protrusions, and the powder coating material and the particle-adhering core material 41 for protrusions are contacted. You may make it rotate with it.

The powder coating and the particle-attached core material 41 for protrusions
After the surface pressing step and the second heating step are finished, the sheet is naturally cooled at room temperature or cooled by blowing air,
As a result, a resin layer 14 in which the powder coating material 12 is completely solidified is formed on the surface of the core material 11, and the particles 13 for protrusion are strongly fixed by the resin layer 14.

In the above description, the powder coating material attaching process and the projection particle attaching process are divided into the powder coating attaching process and the projection particle attaching process, but they may be performed in one process. In that case, the powder coating material 11 and the projection particles 13 may be mixed in advance at an appropriate mixing ratio, and the powder coating material 11 and the projection particles 13 may be simultaneously attached to the core material 11 by one fluidized tank.

[0039]

Example: Free cutting steel (SUM23L) with a diameter of 12.865
± 0.005 mm and total length 330.25 mm were cut, and electroless nickel plating was processed by 4 to 5 μm to obtain a core material. In order to apply electric field fluidized powder coating to this core material, polyester / epoxy powder coating (V-PET 1340 QDLB, Dainippon Paint Co., Ltd.) was applied on the bottom plate of the first fluid tank.
Made, average particle size: 25 μm, bulk density: 0.55 g / c
m ³ ) was charged to disperse the powder coating material while vibrating the vibrating plate. A voltage of -26 kV was applied to the charging needle, and 0.04 MPa was applied from the blowing tube, the cloud pressure in the first flow tank was 0.05 MPa, and the powder coating material was attached by electrostatic force. The core material held by the holding shaft passed through the first flow tank over 1 minute at a speed of 2 m / min. As a result of measuring the layer thickness of the powder coating adhered by a non-contact laser scanning micrometer (LSM-3100, manufactured by Mitutoyo Co., Ltd.),
It was 20 μm.

Subsequently, on the bottom portion of the second fluidized tank, alumina particles (Morundum A # 280, manufactured by Showa Denko KK,
An average particle diameter of 48 μm and a bulk density of 2.2 g / cm ³ ) were added to disperse the powder coating material while vibrating the vibrating plate. A voltage of -20 kV was applied to the charging needle, 0.03 MPa was applied from the blow-out tube, and the cloud pressure in the second flow tank was 0.0.
The powder coating was adhered by electrostatic force at 25 MPa. The powder coating-coated core material mounted on the fixed shaft passed through the second flow tank at a speed of 2 m / min for 1 minute. As a result of measuring the layer thickness of the entire adhesion layer of the particle coating core material for powder coating and projections by the non-contact laser scanning micrometer,
It was 37 μm.

The powder coating material and the particle-adhered core material for projections that passed through the first and second flow tanks passed the first heating step by high frequency induction heating at a speed of 2 m / min for 45 seconds. A high frequency generator (SBT-EH40, manufactured by Shimada Rika Kogyo Co., Ltd.) generates a high frequency of 20 kHz (50 V, 68 A),
The outer surface of the core material was heated to 180 ° C. in a second. Then, the second heating step by far-infrared heating at a speed of 2 m / min,
It passed in 6 minutes. The temperature inside the second heating step was kept constant at 230 ° C. by far-infrared heating.

The surface pressing step was arranged so as to be performed at the time when 1/2 hour (about 3 minutes) in the second heating step.
With the same configuration as in FIG. 3, the two pressing rotary members are fluororesin rollers (diameter 200 mm, total length 210 mm), and the space between the fluororesin rollers is the product outer diameter dimension standard of the paper transport roller. The interval was set to 12.938 mm with respect to 935 ± 0.005 mm, and one fluororesin roller was rotated at a speed of 13 rotations per minute.

Thereafter, the powder coating material and the core material to which the particles for protrusions are attached are allowed to cool to obtain a paper conveying roller in which the particles for protrusions are fixed on the surface of the core material by the solidified material after the powder coating material is cured or melted.

100 sheet conveying rollers were manufactured by the manufacturing method of the above embodiment. In addition, as a comparative example, 100 pieces were manufactured by omitting only the surface pressing step from the manufacturing method of the example. Next, the outer diameter dimensions of the sheet conveying rollers of the example and the comparative example were measured by the non-contact laser scanning micrometer. In Table 1 below, “maximum” is the maximum value of the diameter including the end (outer end) of the particles for protrusions located on the surface layer of the paper transport roller. The "minimum" is the minimum value of the diameter of the projection particles including the end (outer end).

[0045]

[Table 1]

The sheet conveying roller of the embodiment according to the manufacturing method of the present invention has a diameter of 12.935 ± which is a product outer diameter dimension standard.
97 of 100 pieces were included in the 0.005 mm standard.
On the other hand, in the comparative example, the number was 68 out of 100.

Next, FIG. 5 shows a method of measuring the static friction coefficient of the sheet conveying roller. Printer paper 62 (high-gloss film HG101, manufactured by Canon Inc., length 120 mm,
30 mm in width) is arranged so as to make contact with a quarter circumference, and the weight 63 (50 g) is fixed vertically to increase the adhesion between the paper and the roller as a load (w) at one end of the paper. Then, the other end of the printer paper 62 was attached to the force gauge 64. In FIG. 5, the paper conveyance roller 61 is moved clockwise (the direction in which the weight hangs) 1
The printer paper 62 is rotated at a speed of 50 revolutions per minute.
Was pulled toward the side of the paper transport roller 61, and the force gauge 64 measured. The coefficient of static friction was determined from the measured value (f; N) using the following mathematical formula. Static friction coefficient = (2 / π) × ln (f / w)

The static friction coefficient of the example was 0.869 and that of the comparative example was 0.887. Since the surface pressing step is performed in the example, the static friction coefficient is slightly reduced,
Since the standard value is 0.75 or more, the condition is sufficiently satisfied.

[0049]

As shown and described above, according to the method of manufacturing the paper conveying roller of the present invention, the powder coating material and the projection-attached particle-attached core in which the powder coating material and the projection particles are attached to the surface of the core material. During the heating and solidifying process for the material, the surface of the powder coating material and the core particles with particles for protrusions which are being heated are pressed to remove the particles for protrusions into the powder coating material or the melt of the powder coating material. Since the surface pressing process is performed by pushing the paper into the paper, the amount of projection particles exposed from the resin layer (projection amount) can be easily controlled, and a paper conveyance roller with a constant surface friction resistance and sufficient efficiency can be produced efficiently and economically. Can be manufactured.

Further, according to the invention of claim 2, the powder coating material and projection particle adhering step includes a powder coating material coating step of forming the powder coating material-adhering core material by adhering the powder coating material to the surface of the core material. The step of attaching projection particles onto the surface of the powder coating is performed by the step of attaching projection particles on the surface of the powder coating core material to form the powder coating and the particle attachment core material for projection. It is easy to expose and adhere, and it is easy to make the surface friction resistance of the sheet conveying roller obtained through the subsequent heat solidification step and surface pressing step sufficient.

According to the third aspect of the invention, in the surface pressing step, the powder coating material and the protrusions are attached to the rotatable pressing roller whose rotation axis is parallel to the particle-adhering core material for the powder coating material and the protrusions. While pushing the particle-attached core material, the powder coating material and the protrusion-attached particle-attached core material are pushed into the powder coating material or the melt of the powder coating material by rotating the particle-attached core material at least one revolution. The exposure amount (projection amount) of the working particles from the resin layer can be controlled efficiently and uniformly.

Further, according to the invention of claim 4, during the surface pressing step, the powder coating material and the particle-adhering core material for projections are sandwiched between two pressing rotating bodies, and the powder coating material and the particle-adhering core material for projections are sandwiched. The resin particles of the projection particles can be more efficiently introduced because the projection particles are pushed into the powder coating material or the melt of the powder coating material by rotating at least one rotation while contacting the two pressing rotating bodies. The amount of exposure (projection amount) from can be controlled. In addition, according to the invention of claim 5, one of the powder coating material and the particle-adhering core material for protrusions and the pressing rotator are driven to rotate in one direction. Since any of the pressing rotating bodies can be rotated, the structure of the device is simple and the control of the device is easy.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a sheet carrying roller according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an electric field fluidized powder coating device.

FIG. 3 is a schematic top view showing an example of an apparatus used in the surface pressing step.

FIG. 4 is a schematic top view showing another embodiment of the apparatus used in the surface pressing step.

FIG. 5 is a schematic diagram showing measurement of static friction coefficient.

FIG. 6 is a partially enlarged cross-sectional view of a conventional paper transport roller.

[Explanation of symbols]

10 Paper transport roller 11 core material 12 Powder coating 13 Particles for protrusion 14 Resin layer 20 Electric field fluidized powder coating equipment 21 Fluid tank 41 Powder coating and core material with particles for protrusions 42,43 Rotating body for pressing RH far infrared irradiation device

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Claims (5)

[Claims] 1. A powder coating and projection particle adhering step of forming a powder coating and a projection-adhering particle adhering core material by adhering powder coating and projection particles to a core material surface, and the powder coating and projection. The core material is coated with a resin layer formed by curing or melting and solidifying the powder coating material by a heating and solidifying step of heating the particle coating core material to cure or melt and solidify the powder coating material. In the method for manufacturing a paper transport roller in which the particles for protrusions are embedded in a layer in a partially exposed state, in the middle of the heating and solidifying step, the surface of the powder coating material and the particles-attached core material for protrusions during heating is A method of manufacturing a sheet conveying roller, comprising performing a surface pressing step of pressing and pressing the projection particles into the powder coating material or a melt of the powder coating material. 2. A powder coating material and a projection particle attaching step, wherein the powder coating material is attached to the surface of a core material to form a powder coating material-bearing core material, and the powder coating material-bearing core material. 2. The method for manufacturing a paper carrying roller according to claim 1, further comprising a step of attaching particles for protrusion to the surface of the sheet to form a powder coating material and a core material for attaching particles for protrusion. 3. In the surface pressing step, while contacting the powder coating material and the particle-adhering core material for projections with a rotatable pressing body whose rotation axis is parallel to the powder coating material and the particle-adhering core material for projections, 3. The projection particles are pushed into the powder coating material or a melt of the powder coating material by rotating the powder coating material and the projection-attached particle-attached core material at least once. Manufacturing method of the paper transport roller. 4. The pressing rotary body comprises two parallel to each other and is rotatable in the same direction, and the powder coating material and the projection-adhering particle-attached core material are sandwiched between the two pressing rotary bodies,
It is possible to push the projection particles into the powder coating material or the melt of the powder coating material by rotating the powder coating material and the particle-attached core material for the projection particles at least once while contacting the two pressing rotary bodies. The method for manufacturing a sheet conveying roller according to claim 3, wherein 5. The method for manufacturing a sheet conveying roller according to claim 3, wherein any one of the powder coating material, the particle-attached core material for protrusions, and the pressing rotator is driven to rotate in one direction.