JP2002086064A - Method for manufacturing sheet conveying roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a sheet conveying roller, in which the process is simplified to reduce a cost. SOLUTION: A coating material having oil resistance is applied to the whole area of an outer peripheral surface including the journal part 52 of a roller body 51 consisting of a highly rigid material, to form a coating layer 53. A ceramic powder is sprayed onto the outer peripheral surface of the coating layer 53 excluding at least the journal part 52, thereby sticking the ceramic powder to the coating layer 53A excluding the journal part 52 to form the sheet conveying roller.

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 conveying roller formed by adhering ceramic powder to a coating layer formed on an outer peripheral surface of a roller body.

[0002]

2. Description of the Related Art Generally, a recording apparatus such as a printer has a driving roller and a driven roller, and these are operated in cooperation to form, for example, plain paper, coated paper, OHP (overhead projector) sheet, glossy paper, or glossy paper. The apparatus is provided with a sheet conveying device that sandwiches and conveys a sheet such as a film.

In this type, a driving roller has a roller body of a round steel bar made of a highly rigid material, and this roller body is coated with electroless nickel plating for rust prevention over the entire outer peripheral surface including a journal portion. And further apply an organic paint to the outer peripheral surface of the roller body other than the journal portion to form a coating layer,
It is formed by adhering ceramic powder on this coating layer. Alternatively, it is formed by applying electroless nickel plating to the entire outer peripheral surface including the journal portion, and applying an organic paint mixed with ceramic powder to the outer peripheral surface of the roller body other than the journal portion.

[0004]

However, in the conventional configuration, two steps of a step of applying electroless nickel plating and a step of applying an organic paint are required, and the outer peripheral surface of the roller body other than the journal portion is required. At the stage of applying the organic paint, the journal portion must be masked with a masking tape, which complicates the manufacturing process and increases the manufacturing cost of the drive roller.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a sheet conveying roller which simplifies a manufacturing process and reduces a manufacturing cost.

[0006]

According to a first aspect of the present invention, an oil-resistant paint is applied to the entire outer peripheral surface including the journal portion of a roller body made of a highly rigid material to form a coating layer. The method is characterized in that ceramic powder is sprayed on the outer peripheral surface of the coating layer excluding at least the journal portion, and the ceramic powder is adhered to the coating layer other than the journal portion to form.

According to the present invention, plating is achieved, the number of manufacturing steps is reduced as compared with the prior art, and the manufacturing cost is reduced. In addition, since the oil-resistant paint remains on the journal portion, even if grease is applied to the sliding surface with the bearing, the paint does not come off and the durability is improved.

According to a second aspect of the present invention, when the ceramic powder is adhered to at least a coating layer other than the journal portion, the roller body is horizontally supported in a coating booth. The method is characterized in that, while the main body is rotated around an axis, a ceramic powder that is weakly charged from above is dropped in a state close to a natural fall, and the ceramic powder is attached to a coating layer to form.

In the present invention, the ceramic powder, which is weakly charged from above, is dropped in a state close to spontaneous drop, and the ceramic powder is attached to the coating layer to form a uniform thickness. The coating performance is improved.

According to a third aspect of the present invention, in the second aspect, the ceramic powder is weakly charged at a potential of about 20 KV or less using a corona gun for electrostatic coating and applied. Is what you do.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an ink jet printer as an embodiment of a recording apparatus according to the present invention, with a part thereof omitted. FIG. 2 is a side sectional view of the ink jet printer of FIG.

A printer 10 as a recording apparatus shown in these figures is an ink jet printer which performs recording by ejecting ink particles from a number of nozzles (not shown) to a sheet S, and includes a carriage 11 and a recording The head 12, the sheet feeding device 1 illustrated in the upper right of the figure
3. It includes a sheet transporting device 14, a sheet discharging device 15, and a motor control device (not shown) as a motor control device for the recording device illustrated in the lower right of the drawing. This motor control device controls a carriage drive motor (not shown) as a recording device motor for driving the carriage 11. Further, the printer 10 includes a main frame 17 for mounting the above-described device and the like, and a first sub-frame 1.
8, a second sub-frame 19, a pair of left side frames 20, and a right side frame (not shown).

Here, the sheet S is made of plain paper, coated paper, O
For example, a single sheet such as an HP (overhead projector) sheet, glossy paper, glossy film, or the like.

As shown in FIG. 2, the sheet supply device 13 sandwiches the sheet S between a supply roller 21, a hopper 22 for urging the sheet S toward the supply roller 21, and the supply roller 21. And a separation pad 23 for separating the sheet S by pressing. A plurality of sheets S are set in the hopper 22. When the sheets S are supplied, the sheets S are pressed by the hopper 22 toward the supply roller 21 which rotates once, and are separated by the separation pad 23. Only one sheet S is supplied to the sheet conveying device 14.

The sheet S supplied from the sheet supply device 13 to the sheet conveying device 14 is fed by a lower guide 24 attached to the first sub-frame 18 and an upper guide 25 attached to the main frame 17. It is guided to the transport device 14.

The sheet conveying device 14 includes a driving roller 2
6 and the driven roller 27 so that the sheet S can be nipped,
The sheet S is moved in the sub-scanning direction B by the driving of the driving roller 26.
(FIG. 1). The sub-scanning direction B is a direction orthogonal to the main scanning direction A of the carriage 11.

As shown in FIG. 1, the drive roller 26 is supported between the left side frame 20 and the right side frame so as to be rotatable, and is rotatably driven by a roller drive system 28 shown at the lower left in FIG. Is done.

The roller drive system 28 includes a roller drive motor 31 mounted on the left side frame 20, a motor pinion gear 32, an intermediate gear 33, and a drive roller gear 34. The motor pinion gear 32 is rotatably mounted on the motor shaft of the roller drive motor 31.
The drive roller gear 34 is rotatably attached to one end of the drive roller 26 (one end on the left side frame 20 side). The intermediate gear 33 is rotatably supported by the left side frame 20 and meshes with the motor pinion gear 32 and the driving roller gear. Accordingly, the drive roller 26 is driven to rotate via the motor pinion gear 32, the intermediate gear 33, and the drive roller gear 34 by the drive of the roller drive motor 31.

As shown in FIG. 2, two driven rollers 27 are rotatably juxtaposed on one upper guide 25, and a plurality of these upper guides 25 are provided in the axial direction of the drive roller 26. Accordingly, the driven roller 27 has its shaft 2
7A are arranged along the axial direction of the drive roller 26 so as to be aligned with the axial direction of the drive roller 26. Each upper guide 25
As shown in FIG. 2, the driven roller 27 is pivotally supported by the main frame 17 and is urged by a torsion spring 30 also supported by the main frame 17. Is done.

Accordingly, the driven roller 27 is configured to be rotatable with respect to the rotation of the driving roller 26. Therefore, the sheet S is placed between the driving roller 26 and the driven roller 27.
Is supplied, the sheet S is conveyed below the recording head 12 while being sandwiched between the driving roller 26 and the driven roller 27.

As shown in FIGS. 1 and 2, the carriage 11 is slidably inserted into a carriage guide shaft 36 and slidably engaged with an upper end 17A of the main frame 17. The carriage guide shaft 36 is fixed to and supported by the left side frame 20 and the right side frame, and is disposed in parallel with the drive roller 26. Accordingly, the carriage 11 is provided so as to be movable (scanned) without rotating around the carriage guide shaft 36 in the main scanning direction A that matches the axial direction of the carriage guide shaft 36 and the drive roller 26.

The carriage 11 is scanned by a carriage drive system 29 including a carriage drive motor 37 and a timing belt 38. That is, the carriage drive motor 37 is fixedly attached to the right side frame side of the main frame 17, and the drive pulley 39 is attached to the motor shaft of the carriage drive motor 37 so as to rotate integrally therewith. A driven pulley 40 is rotatably supported on the frame 20 side. The timing belt 38 is driven by these drive pulleys 39.
The carriage 11 is wound around the timing belt 38 above or below the timing belt 38 in FIG.
Are combined. Therefore, by the forward or reverse rotation of the carriage drive motor 37, the carriage 11 is guided by the carriage guide shaft 36 and the upper end 17A of the main frame 17 via the timing belt 38, and is turned rightward or leftward in the main scanning direction A in FIG. Is scanned.

The above-described carriage drive motor 37, timing belt 38, drive pulley 39, and driven pulley 40 constitute a carriage drive system 29. Here, a DC motor is employed as the carriage drive motor 37.

The recording head 12 is provided below the carriage 11 and has a number of nozzles (not shown). The recording head 12 ejects ink particles from these nozzles by the action of an actuator using, for example, a piezo element, and records and records an image (including characters) on the sheet S. Ink is supplied to the recording head 12 from an ink tank 41 mounted on the carriage 11.

The recording operation by the recording head 12 is performed while the carriage 11 scans in the main scanning direction A.
The ejection of the ink particles from the nozzles 2 causes recording of one line, and each time the recording of one line is performed, the sheet conveying device 14 moves the sheet S by a predetermined amount (normal line spacing).
It is carried out by transporting and repeating these operations. The sheet guide member 4 is provided below the recording head 12.
2 are provided. The sheet guide member 42 has a protrusion 43 protruding toward the recording head 12 at an appropriate position along the carriage guide shaft 36. The protrusion 43 supports the lower surface of the sheet S and performs recording. The distance between the head 12 and the sheet S is defined. Even if the ink adheres to the upper surface of the sheet S and the sheet S undulates, the protrusions 4 are formed so that the sheet S can be transported appropriately.
The corrugated sheet S is stored between the sheet 3 and the upper surface of the sheet guide member 42.

The sheet discharge device 15 includes a discharge drive roller 44 and a driven star wheel 45, and the discharge drive roller 44 is positioned below the second sub-frame 19. The driven star wheels 45 are rotatably supported by the second sub-frame 19 and are provided in a plurality along the axial direction of the discharge drive roller 44. The discharge drive roller 44 and the driven star wheel 45 discharge the sheet S out of the printer 10 when the recorded sheet S is carried in.

In the above configuration, a driven roller (second sheet conveying roller) 27 constituting the sheet conveying device 14 is used.
As shown in FIG. 3, is formed by forming a coat layer 27b on the surface of an elastic roller (for example, a rubber roller) 27a by, for example, fluorine coating of a low friction material.

The hardness of the elastic roller 27a is 60 in rubber hardness.
° to 90 °. If the hardness exceeds 95 °, the width (length in the sheet conveyance direction) of the sandwiching portion (nip portion) N with respect to the sheet S when pressed against the drive roller 26.
When the hardness is less than 60 °, the driven roller 27 is excessively deformed and the biting of the sheet S becomes unstable.

Coating layer (fluorine coating layer) 27b
Has a thickness of, for example, 5 to 20 μm. This thickness is 20
If it exceeds μm, smooth elastic deformation of the elastic roller 27a itself is hindered. If it is too thin below 5 μm,
This is because the friction coefficient of the driven roller 27 with respect to the sheet S cannot be reduced.

If the coefficient of friction is high, the leading edge of the sheet S passes through the nip portion N in order to turn up when the leading edge of the sheet S bites the nip portion N or to remove the skew of the sheet S (prevent skew). Thereafter, when the driving roller 26 and the driven roller 27 are reversely rotated once until the leading end of the sheet S passes through the nip portion N in the reverse direction, and then rotated forward again, the leading end of the sheet S may be broken. . An appropriate value of the friction coefficient is 0.30 or less, and to achieve this, the thickness of the coat layer 27b needs to be 5 μm or more. When the elastic roller 27a is formed of a rubber roller, the rubber roller contains a plasticizer, and when the plasticizer elutes on the surface of the driven roller 27, this adheres to the surface of the sheet S, and for example, the printed ink is printed. There is a possibility that the dot diameter becomes small, and a portion where the plasticizer adheres and a portion where the plasticizer does not adhere become a pattern, resulting in roller trace marks. Further, when the plasticizer adheres to the paint of the drive roller 26, it reacts with the paint,
This may be dissolved. In order to solve these problems, the elution of the plasticizer can be prevented by setting the thickness of the coat layer 27b to 5 μm or more.

In this embodiment, the driving roller (first sheet conveying roller) 26 is manufactured without plating, which is different from the conventional manufacturing method.

FIG. 4 shows an apparatus for forming a coating layer.

As described above, the drive roller 26 has the pipe-shaped roller main body 51 made of a highly rigid material. As shown in FIG.
Is rotatably supported by a chuck 71, and while the roller body 51 is being rotated about an axis, an organic paint having excellent oil resistance is applied by using a tribo gun 54 for electrostatic painting arranged above, Roller body 5 including a journal 52 to be fitted into a bearing (not shown) by
The coating film layer 53 is formed on the entire outer peripheral surface of the substrate 1. The tribo gun 54 is movable left and right in the figure.

This organic paint is an epoxy-polyester fine particle powder paint. When applying the organic paint, for example, the roller body 51 may be used as a single unit in the state of-
(Negative) potential. Then, while spraying the paint toward the roller main body 51 by using the tribo gun 54, the spray particles are charged to + (plus) high potential. The charged paint is adsorbed on the outer peripheral surface of the roller body 51, and the coating layer 53 is formed thereon. The thickness of the coating film layer 53 is set to 8 μm to 20 μm in consideration of the diameter of the ceramic powder 61 described later, and is appropriately adjusted according to the ejection amount and the ejection time of the powder paint. The roller body 51 on which the coating layer 53 is formed
5 through a handling robot (not shown)
Is transferred to another painting booth 55 shown in FIG.

The coating booth 55 has a pair of chucks 56 at its lower part for supporting the roller body 51 substantially horizontally. The chuck 56 holds both ends 51 a of the roller main body 51, and is further fixed to the rotation driving member 57 so that the held roller main body 51 is rotated around the axis of the roller main body 51, for example, at 100 rpm to 500 rpm.
It is rotated slowly at a low speed of about m. It is clear that the roller body 51 may be supported slightly obliquely.

A corona gun 58 is provided above the painting booth 55.
The corona gun 58 moves right and left on the shaft 59 in the figure. Reference numeral 60 denotes an exhaust mechanism, which is installed below the painting booth 55. The amount of suction air from the exhaust mechanism 60 is appropriately set, and a slow downward airflow is formed in the coating booth 55.

In the coating booth 55, the roller body 5
The ceramic powder 61 (FIG. 3) is electrostatically adsorbed on the coating layer 53 </ b> A other than the one journal 52 almost uniformly around the entire circumference.

At the time of this electrostatic coating, first, the roller body 5
In order to mask the first journal portion 52, the shield 7
3 are fixedly arranged.

As shown in FIG. 6, the shield 73 includes a first plate 74 having an inverted U-shaped groove 74a and a second plate 75 having a semicircular groove 75a. An arc groove 76 is formed by combining the plates 74 and 75, and the roller body 51 is configured to be rotatable around the axis in the arc groove 76. Note that the shield 73 is not limited to the above configuration.

Then, the chuck 56 and the rotary driving member 5
The surface potential of 7 is set to be substantially equal to the potential of the roller body (work) 51, and the potential of the coating booth 55 is set to the ground potential.

Next, the potential applied to the corona gun 58 is set to 2
As a weak potential of 0 KV or less, the corona gun 5
The pressure of the air supplied to 8 is set to a low value of 0.2 Mpa or less, and while moving the corona gun 58 left and right in FIG. Is dropped in the vertical direction in a state close to a natural drop, and the ceramic powder 61 is electrostatically adsorbed almost uniformly on the entire periphery of the coating layer 53A except the journal portion 52.

In this case, the ceramic powder 61 is
3 without entering the journal section 52 side,
The rounding of the ceramic powder 61 into the journal portion 52 is suppressed. The ceramic powder 61 that has been electrostatically adsorbed comes into contact with the coating layer 53A and further enters the coating layer 53A.
1 adhere to the outer peripheral surface.

The journal 52 of the roller body 51
Is a portion fitted into a bearing (not shown) of the printer 10.

In this embodiment, a paint having excellent oil resistance is applied to the journal portion 52, and the paint remains on the journal portion 52. Therefore, even if grease is applied to the sliding surface with the bearing, the paint is not applied. There is no peeling, and the durability is improved.

In this embodiment, the ceramic powder 61 is adhered to the portion other than the journal portion 52. Strictly speaking, it is sufficient to adhere the ceramic powder 61 to a portion of the printer 10 where the sheet S transport force is required.

In this embodiment, the coating booth 55 itself is grounded, and the air flow in the coating booth is formed in a slow downward flow, so that the ceramic powder 61 is almost naturally falling vertically downward. The roller body 51, which is horizontally supported and falls below the falling direction,
Since it is slowly rotated at a low speed, the ceramic powder 6
1 are evenly dispersed and do not concentrate on one place. Therefore, the accuracy of the outer diameter of the roller body 51 is improved, and the particles of the ceramic powder 61 tend to stand vertically with respect to the surface of the roller body 51.

Therefore, the particles of the ceramic powder 61 are uniformly distributed, and most of the particles adhere to the top portion outward.

FIGS. 7 and 8 show the relationship between the potential applied to the corona gun 58 and the film thickness. Here, it is desirable that the film thickness be large, and that this film thickness be uniform along the axial direction and the radial direction of the roller body 51.

As shown in FIGS. 7 and 8, the corona gun 5
In the case where the potential applied to 8 is slightly weakened to 20 KV or less, desirably, when it is weakly charged in the range of 0 to 10 KV, a desired film thickness is secured. Along a small variation along the desired variation range. When a potential higher than 20 KV is applied, a desired film thickness cannot be secured.

In the present embodiment, the ceramic powder, which has been weakly charged to 20 KV or less from above, is dropped in a state close to a natural fall, and is formed by adhering to the coating layer.
The film thickness becomes uniform, and the coating film performance can be improved.

The application of the ceramic powder 61 is not limited to the application by the electrostatic coating method as long as the ceramic powder 61 is sprayed vertically downward in a state close to a natural fall. Spray gun type spraying may be used, or ceramic powder 61 may be sprayed in a cloud shape.

The ceramic powder 61 is made of, for example, aluminum oxide (alumina Al ₂ O ₃ ) or silicon carbide (Si
C) or silicon dioxide (SiO ₂ ) having an average particle size of 20
It is manufactured by crushing to a size of μm to 70 μm, and the protrusion 63 is relatively sharply pointed by the crushing. Ceramic powder 61
When a certain amount of abutment comes into contact with the coating film layer 53 and enters the coating film layer 53 to a certain extent, the attraction force is reduced, so that the projections 63 project from the coating film layer 53. In order for the drive roller 26 to apply a necessary and sufficient frictional force to the sheet S, the roller body 5
The ratio of the area occupied by the ceramic powder 61 to the area of the surface 1 is set to 20% to 80%.

The ceramic powder 61 is applied to the journal 5
After being attached to the coating layer 53A other than the
6 is exposed to an atmosphere of about 180 ° C. for 20 to 30 minutes and fired, whereby the coating layer 53 is hardened and the ceramic powder 61 is fixed to the roller body 51.

As a result of measuring the surface of the driving roller 26 thus formed as an example with a surface roughness meter, Ry was 38.
μm to 50 μm, Rz was 25 μm to 32 μm, and a relatively uneven surface shape was obtained. Then, the sheet S having a width of 35 mm was sandwiched between the driving roller 26 and the driven roller 27 with a normal load, the rotation of the driving roller 26 was fixed, and the dynamic friction coefficient μ when the sheet S was pulled out was measured. 0.88 or more, a high sheet conveying force was obtained. This ceramic powder 61 has a coating layer 5
3 is fixed in a state where it has sufficiently penetrated into the roller 3, so that it does not fall off and a driving roller having excellent durability can be obtained.

In the above configuration, the coating layer 53 is formed on the journal portion 52 of the roller main body 51. Since the coating layer 53 is formed by applying an oil-resistant paint, the printer In the case where the journal 52 is incorporated, even if grease is applied to the journal portion 52 and fitted in a bearing (not shown), the journal portion 52 sufficiently withstands sliding and abrasion, and can be used with conventional plating including rust prevention. It has the same effect.

Further, in the above configuration, since so-called plating-less is achieved at the time of manufacturing the drive roller 26, the number of manufacturing steps is reduced by one compared with the related art, and the manufacturing cost is correspondingly reduced. In addition, the use of the shield 73 eliminates the step of winding the masking tape, thereby simplifying the manufacturing process.

Although the present invention has been described based on one embodiment, the present invention is not limited to this. For example, in the above-described embodiment, the roller body 51 is a pipe, but is not limited thereto, and may be a solid round steel bar. In the above-described embodiment, the application of the powder paint is performed by the electrostatic coating method. However, the present invention is not limited to this, and a known liquid paint, for example, an acrylic liquid paint is sprayed by a spray coating device (not shown) using a spray gun. Roller body 5
Alternatively, a method of jetting toward 1 may be used. The liquid paint is adhered to the roller body 51 to form a coating layer 53. The thickness of the coating layer 53 is also 8 μm to 20 μm.
Is set to

In the above embodiment, the application of the powder paint and the application of the ceramic powder are performed in separate coating booths. However, the present invention is not limited to this, and it is apparent that the coating may be performed in the same coating booth. It is.

[0060]

According to the present invention, plating-free is achieved, the number of manufacturing steps is reduced as compared with the conventional method, the manufacturing cost is reduced, and the oil-resistant paint remains on the journal, so that the sliding with the bearing is achieved. Even if grease is applied to the surface, the paint does not come off and the durability can be improved.

In the present invention, the ceramic powder, which is weakly charged from above, is dropped in a state close to spontaneous drop, and the ceramic powder is attached to the coating layer to form a uniform thickness. The coating film performance can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an ink jet printer, which is an embodiment of a recording apparatus according to the present invention, with a part thereof omitted.

FIG. 2 is a side sectional view showing the inkjet printer of FIG. 1;

FIG. 3 is a schematic diagram illustrating a configuration of a sheet conveying roller according to the exemplary embodiment of the present invention.

FIG. 4 is an apparatus diagram for forming a coating film layer on a roller body.

FIG. 5 is a view showing a painting booth.

FIG. 6 is a view showing a shield.

FIG. 7 is a diagram showing a relationship between a potential applied to a corona gun and a film thickness corresponding to a measurement location.

FIG. 8 is a diagram showing a relationship between a potential applied to a corona gun and a film thickness.

[Explanation of symbols]

 14 Sheet Conveying Device 51 Roller Body 52 Journal 53 Coating Layer 55 Painting Booth 58 Tribo Gun 61 Ceramic Powder 73 Shield

Claims (3)

[Claims] 1. A coating film layer is formed by applying an oil-resistant paint to the entire outer peripheral surface including a journal portion of a roller body made of a highly rigid material, and the outer peripheral surface of the coating layer excluding at least the journal portion. A method for manufacturing a sheet conveying roller, comprising: spraying ceramic powder on a surface of a sheet and adhering the ceramic powder to a coating layer other than the journal portion. 2. When the ceramic powder is attached to at least a coating layer other than a journal portion, the roller body is horizontally supported in a coating booth, and the roller body is rotated about an axis while being weakened from above. 2. The method according to claim 1, further comprising dropping the ceramic powder charged in a manner similar to a natural fall and attaching the ceramic powder to the coating layer. 3. The method for manufacturing a sheet conveying roller according to claim 2, wherein the ceramic powder is applied by being weakly charged at a potential of about 20 KV or less using a corona gun for electrostatic coating.