JPH06127733A - Paper feeding roller and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the generation of color convergence error by securing the excellent feed precision even for an OHP film, as well as a regular paper sheet. CONSTITUTION:Resists 14 are formed to dot form on the outer peripheral surface 13 of a metal cylindrical body 11, and etching treatment is performed by immersing the cylindrical body into a corrosive solution N. After the etching treatment, each fine projection 16 is formed at the top part of a projection 15 by partially removing the crystalline particles at the top of the projection 15. In the method for easily removing the crystalline particle, carbon steel or alloy steel is used as the material of the cylindrical body, and the particle dimension of the crystal is adjusted by heat treatment, and the crystal particle field is made brittle, or after the etching treatment, nitriding treatment is carried out, and the crystalline particle field is made brittle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed roller applicable to both plain paper and OHP film, and particularly suitable for a color printer.

[0002]

2. Description of the Related Art In recent years, color printers capable of outputting computer graphics and video screens as hard copies have been produced. Such a color printer has a recording paper 51 as shown in FIG. 4, for example.
The ink ribbon 52 having three areas of yellow Y, magenta M, and cyan C is superposed on the above, and the ink is transferred to the recording paper 51 side by the thermal head 53. The recording paper 51 is sandwiched by a paper feed roller 54 and a rubber roller 55, and is reciprocated as shown by an arrow A in the figure by the forward and reverse rotation of the paper feed roller 54. The ink ribbon 52 is
The supply roll 56 winds up and moves to the winding roll 57. Then, in color printing, the recording paper 51 is set to three colors of yellow Y, magenta M, and cyan C of the ink ribbon 52.
The transfer by the thermal head 53 is sequentially repeated three times so as to be overlapped on one area.

In the above color printing, the printing paper 51
If the movement of is incorrect, the transfer position will shift for each color and color shift will occur. Therefore, the paper feed roller 5
No. 4 is required to allow the recording paper 51 to be reliably gripped and accurately fed without slipping.

Conventionally, as the paper feed roller as described above, for example, one in which ceramic grains are sprayed or electrodeposited together with metal on a surface of a metal cylinder to form fine irregularities by the ceramic grains is used. ing.

Further, a paper feed roller has been proposed in which a resist is printed in a dot shape on the surface of a metal cylinder, and a large number of fine protrusions are formed on the surface by immersing in an etching solution for etching. See Kaihei 3-95062). In this roller, as shown in FIG. 4, the diameter w of the top of the protrusion 15 is preferably 25 to 150 μm.
The height h is preferably 30 to 150 μm, and the arrangement interval p of the protrusions 15 is preferably 0.5 to 2.0 mm.

[0006]

However, in the case of the paper feed roller in which the ceramic particles are attached to the surface of the conventional metal cylinder by thermal spraying or electrodeposition, the ceramic particles fall off during use and damage the thermal head. There was a fatal drawback of doing so. Further, since the ceramic particles are adhered by the thermal spraying or electrodeposition after the surface of the metal cylindrical body is polished, the accuracy of the outer diameter of the cylindrical body cannot be sufficiently obtained, and the feeding accuracy of the recording paper decreases. There was a problem.

Further, in the case of the paper feed roller having protrusions formed by the etching process disclosed in Japanese Patent Laid-Open No. 3-95062, although the feeding accuracy for plain paper is sufficiently obtained, the OHP film often used in color printers and the like is used. On the other hand, there is a problem that the amount of protrusions is insufficient and slippery, which causes color shift. As a countermeasure against this, when the pressing force of the paper feed roller 54 and the rubber roller 55 is increased, in the case of plain paper, as shown in FIG. 5, the protrusion 15 of the paper feed roller 54 bites into an emboss 58 on the surface of the paper 51. There is a problem in that the ink 59 is not evenly attached and color unevenness is likely to occur.

On the other hand, in order to improve the bite of the protrusions into the OHP film, the diameter of the tops of the protrusions may be made smaller to make them sharper and sharper, but the diameter of the resist printed in dots becomes smaller. As a result, the resist is peeled off during etching and no protrusion is formed, or the diameter of the top portion is likely to vary depending on the individual protrusions, so the etching conditions become strict,
There is a problem that manufacturing becomes difficult.

Therefore, it is an object of the present invention to obtain uniform and accurate feeding accuracy not only for plain paper but also for OHP film, thereby preventing color misregistration due to misregistration and manufacturing. An easy-to-use paper feeding roller and a method for manufacturing the same are provided.

[0010]

In order to achieve the above object, the paper feed roller of the present invention is one in which a large number of fine projections are formed on the outer peripheral surface of a metal cylindrical body by etching processing. Is characterized in that minute protrusions due to lack of crystal grains are formed on the top of the.

Further, the method of manufacturing the paper feed roller of the present invention comprises a step of forming a resist in a dot shape on the outer peripheral surface of the metal cylindrical body, and a step of etching the outer peripheral surface with a corrosive solution. It is characterized in that a step of removing the crystal grains on the outer peripheral surface is included, and minute protrusions due to the lack of the crystal grains are formed on top of the protrusions formed by the etching process.

In the present invention, the diameter of the resist is
It is preferable that the diameter is 50 to 200 μm, and the diameter of the top portion of the protrusion formed thereby is preferably 30 to 150 μm.

Further, as a preferable method for removing the crystal grains, the cylinder is formed of carbon steel or alloy steel, and the cylinder is heat-treated to adjust the crystal grain size and to form the crystal grain boundaries. Examples include a method of embrittlement and a method of forming protrusions by etching on the outer peripheral surface of the cylindrical body and then nitriding the outer peripheral surface to embrittle the crystal grain boundaries. In this case, in order to efficiently remove the crystal grains, it is possible to forcibly remove the crystal grains by means such as shot peening and barrel polishing after forming the protrusions by etching.

Further, in the present invention, in order to prevent the crystal particles from being lost during the use of the paper feed roller, the outer peripheral surface of the cylindrical body after the crystal particles are removed is subjected to nickel phosphorus plating, hard chrome plating, or the like. It is preferable to apply hard plating.

[0015]

According to the present invention, by applying a resist in a dot shape on the outer peripheral surface of a metal cylinder and etching the same,
The portions not covered with the resist are etched and lowered, and the portions covered with the resist form protrusions. Next, by removing the crystal grains at the tops of the protrusions, minute protrusions are formed at the tips of the protrusions.

As a result, the tops of the protrusions become sharper, and not only soft recording paper such as plain paper but also O
Even for recording paper with a hard surface such as HP film,
The protrusion bites well and can be fed with high accuracy. Therefore, in the case of color printing, it is possible to prevent the color shift due to the position shift.

Further, since it is not necessary to particularly reduce the diameter of the top portion of the projection formed by the etching process, the resist diameter can be increased, the resist is not peeled off during the etching, and the etching condition The tolerance can be increased.

Further, since the paper feed roller of the present invention has a projection formed by etching the surface of a metal cylindrical body, it has a higher dimensional accuracy than a ceramic powder deposited by thermal spraying or electrodeposition. There is no risk of the particles coming off.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a method for manufacturing a paper feed roller according to the present invention. That is, as shown in FIG. 3A, first, the cylindrical body 11 made of metal such as stainless steel, carbon steel, and low alloy steel is formed. As the molding method, various methods such as casting, drawing, and punching of a cylinder can be adopted, but drawing having high production efficiency is preferably adopted. After molding the cylindrical body 11 in this way, if necessary,
The inner peripheral surface and the outer peripheral surface are cut or polished to improve the dimensional accuracy.

Next, the cylindrical body 11 is heat treated to embrittle the crystal grain boundaries. When the material of the cylindrical body 11 is carbon steel or low alloy steel, Cr steel, Mn steel and steel types containing a large amount of P, Sb, N are effective, and after heating to a temperature below the eutectoid temperature, gradual cooling By doing so, the crystal grain boundary becomes brittle. Further, in the case of high alloy steel such as stainless steel, increasing the C and Ni contents promotes embrittlement of crystal grain boundaries. Since the crystal grain size after heat treatment is preferably 20 to 30 μm, the heat treatment temperature is 500 to 7 for carbon steel and low alloy steel.
00 ° C., preferably 500 to 800 ° C. for stainless materials. The outer peripheral surface 13 of the cylindrical body 11 thus formed is in a state in which the crystal grain size is coarse and embrittled, as shown in FIG.

Next, as shown in FIG. 1C, the cylindrical body 1
A dot-shaped resist 14 is formed on the outer peripheral surface of 1. As a method of forming the resist 14, for example, JP-A-3-950
Although a screen printing method such as that disclosed in Japanese Patent No. 62 can also be adopted, Japanese Patent Application No. 3-2627 by the present applicant has the advantage that dots can be formed uniformly over the entire circumference of a cylindrical body.
It is preferable to employ the photoresist disclosed in No. 89. In this method, an ultraviolet curable resin is applied to the outer peripheral surface of the cylindrical body in advance, and while the cylindrical body is rotated by a predetermined angle, ultraviolet rays are irradiated, and the ultraviolet curable resin on the outer peripheral surface of the cylindrical body is exposed in a dot shape. The method is a method of forming a uniform dot-shaped resist without seam by developing after the cylindrical body has been exposed around the entire surface in a dot-like shape and curing the ultraviolet-curing resin in the exposed portion. The diameter of the resist 14 is preferably about 50 to 200 μm.

Next, as shown in FIG. 1D, the cylindrical body 1
1 is immersed in a treatment bath H containing a corrosive solution N to perform etching treatment. As the corrosive solution N, for example, a ferric chloride aqueous solution or the like is adopted. As a result, as shown in FIG. 6E, the portion not covered with the resist 14 is eroded, and only the portion covered with the resist 14 remains without being eroded, and a large number of fine protrusions 15 are formed. To be done. In this case, the diameter and height of the top of the protrusion 15 can be formed to desired values by adjusting the diameter of the resist 14 and the corrosion conditions. The diameter of the top of the protrusion is 5 to 20.
μm is preferable, and the height of the protrusion is preferably 30 to 150 μm.

Finally, the resist 14 is peeled off to form a paper feed roller in which a large number of fine projections 15 are formed in dots on the outer peripheral surface of the metal cylindrical body 11 as shown in FIG. 21 is obtained. In the projections 15 of the paper feed roller 21 thus obtained, some of the crystal grains at the top are missing due to the above-mentioned directionality of etching, and as shown in FIG. The minute protrusions 16 are formed due to the lack. FIG. 2 is an enlarged view of the projection 15 of the paper feed roller 21 thus obtained.

In this embodiment, crystal grains are naturally lost after the above etching treatment due to the directionality of etching, but in order to perform the removal more efficiently, the crystal grains are forcibly crystallized by treatments such as shot peening and barrel polishing. Particles may be omitted.

Further, in order to prevent the crystal grains from being omitted more than necessary, the surface may be hard-plated after the crystal grains are removed. Examples of such hard plating include nickel phosphorus plating and hard chrome plating.

FIG. 3 shows another embodiment of the paper feed roller manufacturing method of the present invention. First, as in the case of the above-described embodiment, as shown in FIG. 4A, a cylindrical body 31 made of metal such as carbon steel or alloy steel is formed, and the inner peripheral surface and the outer peripheral surface thereof are ground as necessary. Alternatively, the dimensional accuracy is improved by polishing.

Next, as shown in FIG. 7B, a dot-shaped resist 34 is formed on the outer peripheral surface of the cylindrical body 31 by the same method as in the above-mentioned embodiment. Then, as shown in FIG. 3C, the cylindrical body 31 is immersed in the processing bath H containing the corrosive solution N for etching. As a result, as shown in FIG. 7D, the portion not covered with the resist 34 is eroded, and only the portion covered with the resist 34 remains without being eroded, and a large number of fine protrusions 35 are formed. To be done.

Then, by removing the resist 34, as shown in FIG. 3E, a paper feed roller 41 in which a large number of fine projections 35 are formed in dots on the outer peripheral surface of the metal cylindrical body 31. Is obtained.

Next, the outer peripheral surface of the cylindrical body 31 is nitrided. As a result, as shown in FIG. 6F, the crystal grain boundaries of the protrusions 35 become brittle, and the crystal grains are likely to drop out. In this case, the thickness of the nitride layer is preferably about 5 to 50 μm.

Finally, by performing shot peening using glass beads or the like and barrel polishing or the like, some of the crystal grains at the top of the protrusion 35 are lost, and as shown in FIG. A minute projection 36 is formed on the top of 35 due to the lack of crystal grains.

Also in this embodiment, similarly to the above-mentioned embodiment, in order to prevent the crystal grains from being removed more than necessary, it is preferable to harden the surface after the crystal grains are removed.

[0032]

As described above, according to the present invention,
A large number of protrusions are formed by forming a resist in the shape of dots on the outer peripheral surface of a metal cylinder and performing an etching process.After that, by partially eliminating the crystal grains on the surface of the protrusions, the top of the protrusion Furthermore, since the minute protrusions are formed, the shape of the top of the protrusions becomes sharper and the bite not only on plain paper but also on the OHP film is improved, which provides accurate feeding accuracy and is suitable for color printing. In this case, it is possible to prevent the color shift. Also,
Even if the diameter of the top portion of the protrusion formed by etching is not reduced, the shape of the top portion of the protrusion can be sharpened, so that the tolerance of the etching condition is increased and the manufacturing is facilitated. Further, since the projection is formed by etching the surface of the metal cylindrical body, the dimensional accuracy is higher than that of the ceramic powder adhered by thermal spraying or electrodeposition, and there is no fear that the particles will fall off.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a paper feed roller according to an embodiment of the present invention.

FIG. 2 is an enlarged explanatory view showing the shape of a protrusion of the paper feed roller of the present invention.

FIG. 3 is an explanatory diagram showing a manufacturing process of a paper feed roller according to another embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a structure of a color printer.

FIG. 5 is an explanatory diagram showing a shape of a protrusion of a conventional paper feed roller.

FIG. 6 is an enlarged sectional view showing a paper feed state by a conventional paper feed roller.

[Explanation of symbols]

 21, 41 Paper feed roller 11, 31 Metal cylinder 13, 33 Outer peripheral surface 14, 34 Resist 15, 35 Projection 16, 36 Microprojection H Treatment tank N Corrosion solution

Claims (6)

[Claims] 1. A paper feed roller in which a large number of fine projections are formed on an outer peripheral surface of a metal cylindrical body by etching, wherein fine projections due to lack of crystal particles are formed on tops of the projections. Characteristic paper feed roller. 2. The paper feed roller according to claim 1, wherein a hard plating layer is provided on an outer peripheral surface of the cylindrical body. 3. A step of forming a resist in a dot shape on the outer peripheral surface of a metal cylinder, a step of etching the outer peripheral surface with a corrosive solution, and a step of removing crystal grains on the outer peripheral surface. A method of manufacturing a paper feed roller, characterized in that minute protrusions due to lack of crystal grains are formed on top of the protrusions formed by the etching process. 4. The method of manufacturing a paper feed roller according to claim 3, wherein after the step of removing the crystal particles, a step of applying a hard plating layer to the outer peripheral surface of the cylindrical body is performed. 5. The crystal grains are formed after the etching process by forming the cylinder body from carbon steel or alloy steel and heat treating the cylinder body to adjust the crystal grain size and embrittle the crystal grain boundaries. 5. The method for manufacturing a paper feed roller according to claim 3, wherein the paper is easily lost. 6. The paper feed roller according to claim 3, wherein after the etching process, the outer peripheral surface of the cylindrical body is subjected to a nitriding treatment to embrittle the crystal grain boundaries so that the crystal grains are easily lost. Production method.