JP6205467B1 - Semiconductive resin roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductive resin roll that is lightweight and can uniformly charge an outer peripheral surface over the entire surface. A semiconductive resin roll is formed of a semiconductive resin and includes a hollow roll body (11) having a first open end and a second open end. The outer peripheral surface (111) of the roll body defines a working surface (111a) at the center and first and second non-working surfaces at both ends. The working surface has a first end on the first open end side of the roll body and a second end on the opposite side. A conductive coating (12) is formed so as to at least partially cover the inner peripheral surface of the roll body. The conductive coating is at least a thickness of the roll body from a position corresponding to the first end of the working surface from a position spaced inward by a distance corresponding to the thickness of the roll body from a position corresponding to the second end of the working surface. The region up to a point separated inward by a distance corresponding to the length is continuously covered. The conductive film exhibits a volume resistivity lower than the volume resistivity exhibited by the semiconductive resin. [Selection] Figure 1

Description

  The present invention relates to a semiconductive resin roll.

  In electrophotographic image forming apparatuses such as copying machines and printers, various semiconductive or conductive rolls including a charging roll, a developing roll, a toner supply roll, a transfer roll and the like are used.

  Conventionally, as these (semi) conductive rolls, the outer surface of a metal shaft (or metal core) is coated or coated with (semi) conductive rubber, elastomer, or foam thereof. ing. However, these rolls have metal shafts, and are proposed to be (semi) conductive resin rolls in which the roll body and journal are made of (semi) conductive resin for reasons such as being heavy (for example, patents) Reference 1 and Patent Reference 2).

JP 2003-262998 A JP 2004-155892 A

  However, the present inventors have found that the outer peripheral surface (cylindrical surface) of the semiconductive resin roll cannot be charged uniformly.

  Therefore, an object of the present invention is to provide a semiconductive resin roll that is lightweight and can uniformly charge the entire outer peripheral surface.

The present invention provides a semiconductive resin roll comprising a hollow roll body formed of a semiconductive resin and having a first open end and a second open end. The outer peripheral surface of the roll body defines a working surface at the center and a first non-working surface and a second non-working surface at both ends, and the working surface is a first open end of the roll body. A first end on the side and a second end on the opposite side. A conductive coating is formed so as to at least partially cover the inner peripheral surface of the roll body. The conductive coating is at least from a position corresponding to the first end of the working surface from a point separated from the position corresponding to the second end of the working surface by a distance corresponding to the thickness of the roll body. An area up to a point separated inward by a distance corresponding to the thickness of the roll body is continuously covered. Then, the conductive coating, wherein the lower volume resistivity than the volume resistivity indicated semiconductive resin shows, metal, a thin film of an alloy or a conductive metal oxide.

  In this invention, the outer peripheral surface of a hollow roll main body comprises a cylindrical surface, or takes a crown shape or a reverse crown shape. Here, the (reverse) crown shape is a shape that gradually increases symmetrically (reverse crown) or decreases (crown) as the diameter of the roll body moves from the axial center of the roll body toward both axial ends. ). The difference between the diameter Do at the center of the roll body and the diameter Di at both ends of the roll body (Do-Di) is called the crown amount. The reverse crown shape has a negative crown amount, and the crown shape has a crown amount of It is a plus. Here, the crown amount of zero corresponds to the cylindrical surface.

  In one embodiment, the inner peripheral surface of the hollow roll main body forms a cylindrical surface when the outer peripheral surface of the hollow roll main body forms a cylindrical surface. Thus, the hollow roll main body in which both the outer peripheral surface and the inner peripheral surface constitute a cylindrical surface can be expressed as a hollow cylindrical roll main body.

  In other embodiments, the inner peripheral surface of the hollow roll body takes a corresponding shape (ie, a crown shape or an inverted crown shape) when the outer peripheral surface of the hollow roll body takes a crown shape or an inverted crown shape, or Constructs a cylindrical surface. When the outer peripheral surface of the hollow roll body takes a crown shape or an inverted crown shape, the inner peripheral surface of the hollow roll body usually constitutes a cylindrical surface.

  In one or more embodiments, the conductive coating is formed over the entire inner peripheral surface of the roll body.

In one or more embodiments, the semiconductive resin exhibits a volume resistivity of 1 × 10 ⁵ to 1 × 10 ¹² Ω · cm.

  In one or more embodiments, the semiconductive resin roll has a shaft inserted into each of the first open end and the second open end of the hollow roll body. Here, at least one of both shafts may be conductive, and the conductive shaft may be in contact with a conductive coating provided on the inner peripheral surface of the hollow roll body.

  In the semiconductive resin roll of the present invention, since the roll body is a hollow body, the roll body is lightweight, and the outer peripheral surface can be uniformly charged throughout.

It is a schematic sectional drawing of the semiconductive resin roll which concerns on the 1st Embodiment of this invention. It is a schematic sectional drawing which shows the semiconductive resin roll which concerns on the 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the semiconductive resin roll which concerns on the 3rd Embodiment of this invention.

  Hereinafter, some embodiments of the present invention will be described with reference to the drawings as appropriate. These figures are not to scale. Throughout the drawings, the same or similar elements are denoted by the same reference numerals, and repeated description thereof is omitted.

  FIG. 1 is a cross-sectional view of a semiconductive resin roll 10-1 according to the first embodiment of the present invention.

  A semiconductive resin roll 10-1 shown in FIG. 1 includes a hollow cylinder (circular tube) -shaped roll body 11 formed of a semiconductive resin.

  The roll body 11 has a hollow cylindrical body shape, and both ends are open. That is, the roll body 11 has an outer peripheral surface (cylindrical surface) 111, and a first open end 11a and a second open end 11b. In the present specification, the first open end means one open end, and the second open end only means the other open end.

  The semiconductive resin forming the roll body 11 is obtained by blending a conductive agent in a thermoplastic resin, and can also be described as a conductive thermoplastic resin composition. As thermoplastic resins, polyvinyl chloride, polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene resin (ABS resin), acrylonitrile-styrene resin (AS resin), polymethyl methacrylate, polyvinyl alcohol, polyvinylidene chloride, polyethylene terephthalate, etc. General-purpose plastic (general-purpose resin), polyamide, polyacetal, polycarbonate, polyphenylene ether, polybutylene terephthalate, ultra-high molecular weight polyethylene, polyvinylidene fluoride and other engineering plastics (engineering resin), or any combination of these two But not limited to them.

  As the conductive agent blended in the thermoplastic resin, metal powder, metal oxide powder, carbon-based powder, carbon fiber, or the like can be used, but is not limited thereto.

  Moreover, the said conductive thermoplastic resin composition may contain the reinforcing material. The conductive agent exemplified above can also function as a reinforcing material. Moreover, glass fiber can also be used as a reinforcing material.

The volume resistivity of the semiconductive resin constituting the roll body 11 is preferably 1 × 10 ⁵ to 1 × 10 ¹² Ω · cm, more preferably 1 × 10 ⁶ 1 × 10 ¹⁰ Ω · cm. . This volume resistivity range is suitable for charging the roll body, and is economical.

  The roll body 11 may have an outer diameter of 5 to 60 mm, a thickness of 0.25 mm to 24 mm, and an axial length of 210 to 860 mm (a length corresponding to printing on A4 to A0 paper sizes). In other words, the cylindrical surface 111 of the roll body 11 defines the working surface 111a serving as an image forming region at the center and the non-working surfaces 111b and 111c at both ends. The working surface has a first end on the first open end 11a side of the roll body 11 and a second end on the opposite side (the second open end 11b side of the roll body 11).

  A conductive coating 12 is provided on the inner peripheral surface of the roll body 11 so as to cover the entire region corresponding to the working surface 111a.

The conductive film 12 is formed of a conductive material (film material) that exhibits a volume resistivity lower than the volume resistivity exhibited by the semiconductive resin. The coating material preferably has a volume resistivity of 1 × 10 ⁻⁶ to 1 × 10 ⁴ Ω · cm, more preferably a volume resistivity of 1 × 10 ⁻⁶ to 1 × 10 ³ Ω · cm or less. Have. The difference between the volume resistivity exhibited by the semiconductive resin roll body material and the volume resistivity exhibited by the coating material is preferably 1 × 10 ¹ Ω · cm or more.

  In the present invention, the volume resistivity is a value measured in accordance with JIS K6911.

  The conductive film 12 formed on the inner peripheral surface of the hollow cylindrical roll body 11 is formed of a metal such as aluminum, silver, copper, titanium, nickel, or chromium, an alloy thereof, or a conductive metal oxide. be able to. A method for depositing these metals or metal oxides thinly and uniformly on the inner peripheral surface of the hollow cylindrical roll body includes, but is not limited to, vacuum deposition.

  Alternatively, the conductive coating 12 is not limited, but a conductive agent is mixed with a paint such as an acrylic paint, a urethane paint, a silicon paint, a nano paint, an inorganic paint, or a fluorine paint. It can also be formed by a conductive paint whose volume resistivity is adjusted. In this case, as the conductivity-imparting agent, metal powder, metal oxide powder, carbon-based powder, carbon fiber, or the like can be used, but is not limited thereto. A method for forming such a conductive paint thinly and uniformly includes spraying, but is not limited thereto.

  The thickness of the conductive coating 12 can be selected from the range of 0.005 to 500 μm depending on the type of coating material constituting the conductive coating. More specifically, when the coating material is a metal (including an alloy) or a metal oxide, the thickness of the conductive coating 12 is preferably 0.005 to 10 μm, but the thickness is too thin. On the other hand, there is a risk that the energization efficiency may be lowered. When the conductive material is a metal (including an alloy) or a metal oxide, the thickness of the conductive coating 12 is more preferably 0.01 to 1 μm.

  Further, when the coating material is a conductive paint, the thickness of the conductive coating 12 is preferably 1 to 500 μm, but if the thickness is too thin, there is a possibility that the current-carrying efficiency may be reduced. If it is too thick, problems such as difficulty in processing may occur. When the coating material is a conductive paint, the thickness of the conductive coating 12 is more preferably 10 to 200 μm.

  The semiconductive resin roll having the above-described configuration can be manufactured by, for example, producing a hollow cylindrical body (roll body) by extrusion molding or injection molding and then forming a conductive coating on the inner peripheral surface of the roll body. . When manufacturing a roll body by extrusion molding, a semi-conductive resin pellet is introduced into a continuous extrusion machine having a die that matches the outer diameter of the roll body and a core that matches the inner diameter of the roll body. A roll body can be manufactured by forming a cylindrical body and cutting it into a required length. Also, when manufacturing a roll body by injection molding, the roll body is manufactured by introducing semiconductive resin pellets into an injection molding machine in which a mold capable of obtaining the outer diameter, inner diameter, and length of the roll body is placed. Can do.

  The method for producing the conductive film is as described above.

  The semiconductive resin roll 10-1 described above can be supported at both ends for rotation. In that case, the length of the roll main body 11 can also be extended as needed. In order to charge the image forming area on the surface of the roll body 11, the conductive coating 12 can be energized. Alternatively, a solid shaft may be inserted into both open ends so as to come into contact with the conductive coating 12, and current may be supplied from a portion of the shaft protruding from the open end.

  FIG. 2 shows a semiconductive resin roll 10-2 according to the second embodiment. In this semiconductive resin roll 10-2, a conductive coating 12 is provided so as to cover the entire inner peripheral surface of the roll body 11, and a hollow cylindrical or medium is formed inside each of the open ends 11a and 11b. Except that the actual cylindrical shafts 13a and 13b are inserted, it has the same structure as the semiconductive resin roll 10-1 shown in FIG. The shafts 13 a and 13 b are in contact with the conductive coating 12 inside the roll body 11 and protrude outward from the roll body 11.

  It should be noted that at least one of the shafts 13a and 13b may be in contact with the conductive coating 12 and can be energized (that is, conductive). The length by which the conductive shaft is inserted into the roll main body may be sufficient to contact the conductive coating. Moreover, the length in which both shafts protrude from the roll body can be adjusted to the apparatus in which the semiconductive resin roll is incorporated. Of the two axes, the other axis may be non-conductive and the length may be the same as the conductive axis. The description about these shafts is applied when the semiconductive resin roll of the present invention has shafts at both ends (including the case of the semiconductive resin roll according to the third embodiment described below).

  FIG. 3 shows a semiconductive resin roll 10-3 according to the third embodiment. The semiconductive resin roll 10-3 has the same configuration as that of the semiconductive resin roll 10-2 shown in FIG. 2 except that the region where the conductive film is formed is narrow. More specifically, the conductive coating 12 acts on the inner peripheral surface of the roll body 11 from a point separated from the position corresponding to the second end of the working surface 111a by a distance corresponding to the thickness t of the roll body. The region up to the point corresponding to the first end of the surface 111a is continuously covered.

  Although the present invention has been described above with respect to some embodiments, the present invention is not limited thereto. For example, as long as the conductive coating does not lose continuity, there may be a gap with a width equal to or less than the thickness of the roll body from one end to the opposite end in the longitudinal direction of the roll body. Further, the conductive coating covering at least partially the inner peripheral surface of the roll body is at least a working surface from a point separated from the position corresponding to the second end of the working surface by a distance corresponding to the thickness of the roll body. It suffices to continuously cover a region from a position corresponding to the first end to a point separated inward by a distance corresponding to the thickness of the roll body.

  Further, the outer peripheral surface of the hollow roll main body may have a crown shape or an inverted crown shape, and in that case, the inner peripheral surface of the hollow roll main body takes a corresponding shape (crown shape or reverse crown shape), A cylindrical surface may be formed. In these cases, the thickness of the roll body varies from one end toward the center, but may be within the range of the thickness of the roll body in the semiconductive resin roll of the first embodiment.

  Next, the present invention will be further described with reference to examples.

Example 1
A semiconductive resin roll having the structure shown in FIG. 2 was produced.

In this semiconductive resin roll, the conductive coating disposed on the inner peripheral surface of the hollow cylindrical roll body was made of aluminum, and the volume resistivity was 2.7 × 10 ⁻⁶ Ω · cm.

Moreover, the axis | shaft arrange | positioned at the both ends of a roll main body was a product made from stainless steel whose volume resistivity is 6.0x10 <^-5> ohm * cm.

  First, 100 parts by weight of polyacetal (polyplastic M130) as a thermoplastic resin, 7 parts by weight of carbon fiber (1401T30 manufactured by Toray) as a conductivity-imparting agent, and glass fiber (EFT75-01 manufactured by Central Glass Fiber) as a reinforcing agent. ) 6 parts by weight was melt mixed and pelletized to produce a semiconductive resin material constituting the roll body.

  Next, a mold having a shape of a hollow cylindrical body having an outer diameter of 16 mm, an inner diameter of 8 mm, and a length of 320 mm was placed in an injection molding machine, and the pellets were charged therein. Thus, a plurality of roll bodies were formed. The image forming area on the cylindrical surface of the roll body was the center of the cylindrical surface and had a width of 297 mm at the center.

A part of one semiconductive resin part of the produced roll was cut out and the volume resistivity was measured according to JIS K6911. As a result, it was 1.4 × 10 ⁵ Ω · cm.

  Next, an aluminum film having a thickness of 0.5 μm was formed on the entire inner peripheral surface of the formed roll body by vacuum deposition.

  Next, 10 mm of stainless steel shafts each having a diameter of 8 mm and a length of 22 mm were inserted and fixed in both open ends of the obtained roll body. Thus, a desired semiconductive resin roll was produced.

  When this semiconductive resin roll was placed as a transfer roll in the image transfer portion of the printer and subjected to a printing test, it was a good image in 100,000 printing tests, but rarely had no problem with the image. Minute toner omission was observed.

Example 2
In this example, several semiconductive resin rolls were produced in the same manner as in Example 1 except that the number of conductive imparting agents in the semiconductive resin material constituting the hollow cylindrical roll body was changed.

  The semiconductive resin material used in this example is 100 parts by weight of polyacetal (polyplastic M130) which is a thermoplastic resin, 7 parts by weight of carbon fiber (1401T30 made by Toray) which is a conductivity imparting agent, and a reinforcing agent. 5 parts by weight of a certain glass fiber (Central Glass Fiber EFT75-01) was melt-mixed and pelletized.

A part of one semiconductive resin portion of the produced semiconductive resin roll was cut out and the volume resistivity was measured according to JIS K6911. As a result, it was 7.3 × 10 ⁶ Ω · cm.

  When this semiconductive resin roll was arranged as a transfer roll in the image transfer portion of the printer and a printing test was performed, all the good images could be obtained in the 100,000 printing tests.

Example 3
In this example, several semiconductive resin rolls were produced in the same manner as in Example 1 except that the number of conductive imparting agents in the semiconductive resin material constituting the hollow cylindrical roll body was changed.

  The semiconductive resin material used in this example is 100 parts by weight of polyacetal (polyplastic M130) which is a thermoplastic resin, 7 parts by weight of carbon fiber (1401T30 made by Toray) which is a conductivity imparting agent, and a reinforcing agent. 4 parts by weight of a certain glass fiber (Central Glass Fiber EFT75-01) was melt-mixed and pelletized.

A part of one semiconductive resin portion of the produced semiconductive resin roll was cut out and the volume resistivity was measured according to JIS K6911. As a result, it was 9.6 × 10 ⁹ Ω · cm.

  When this semiconductive resin roll was arranged as a transfer roll in the image transfer portion of the printer and a printing test was performed, all the good images could be obtained in the 100,000 printing tests.

Example 4
In this example, several semiconductive resin rolls were produced in the same manner as in Example 1 except that the number of conductive imparting agents in the semiconductive resin material constituting the hollow cylindrical roll body was changed.

  The semiconductive resin material used in this example is 100 parts by weight of polyacetal (polyplastic M130) which is a thermoplastic resin, 7 parts by weight of carbon fiber (1401T30 made by Toray) which is a conductivity imparting agent, and a reinforcing agent. 3 parts by weight of a certain glass fiber (EFT75-01 manufactured by Central Glass Fiber) was melt-mixed and pelletized.

A part of one semiconductive resin portion of the produced semiconductive resin roll was cut out and the volume resistivity was measured according to JIS K6911. As a result, it was 2.7 × 10 ¹¹ Ω · cm.

  When this semiconductive resin roll was placed as a transfer roll in the image transfer portion of the printer and subjected to a printing test, it was found to be a good image in a 100,000-sheet printing test, but rarely had no problem with the image. About a minute toner omission was observed.

Example 5
A semiconductive resin roll having the structure shown in FIG. 3 was produced.

  In this embodiment, the conductive coating disposed on the inner peripheral surface of the hollow cylindrical roll body is shorter than the length between the two open ends by a distance corresponding to a roll body thickness of 4 mm from one open end. there were. Thus, a semiconductive resin roll was produced in the same manner as in Example 2 except that the arrangement of the conductive film was different.

  The produced semiconductive resin roll was placed as a transfer roll in the image transfer portion of the printer, and a printing test was conducted. In a printing test of 100,000 sheets, an image rarely appears near the surface on the side where the conductive film is not exposed. Although fine toner omissions were observed to the extent that there was no hindrance, all of the images were generally good.

Comparative Example 1
A semiconductive resin roll was produced in the same manner as in Example 2 except that the conductive film was not disposed on the inner peripheral surface of the roll body.

  When the produced semiconductive rubber roll was placed as a transfer roll in the image transfer portion of the printer and a printing test was performed, the toner image on the photosensitive drum could not be transferred to the paper surface, and an image could not be obtained.

Comparative Example 2
In this comparative example, several semiconductive resin rolls were produced in the same manner as in Comparative Example 1 except that the number of conductive imparting agents in the semiconductive resin material constituting the hollow cylindrical roll body was changed.

  The semiconductive resin material used in this comparative example is 100 parts by weight of polyacetal (polyplastic M130) which is a thermoplastic resin, 7 parts by weight of carbon fiber (1401T30 made by Toray) which is a conductivity imparting agent, and a reinforcing agent. 7 parts by weight of a certain glass fiber (Central Glass Fiber EFT75-01) was melt-mixed and pelletized.

A part of one semiconductive resin portion of the produced semiconductive resin roll was cut out and the volume resistivity was measured according to JIS K6911. As a result, it was 9.7 × 10 ³ Ω · cm.

  When this semiconductive resin roll was placed as a transfer roll in the image transfer portion of the printer and a printing test was performed, the toner image on the photosensitive drum could not be transferred to the paper surface, and an image could not be obtained.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. The embodiments described above can be implemented in various other forms, and various modifications (omitted, omitted, changed) can be made without departing from the scope of the invention. These modifications are also included in the scope of the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 11 ... Hollow cylindrical roll main body, 11a, 11b ... Open end, 111 ... Cylindrical surface, 111b, 111c ... Non-operation surface, 111a ... Operation surface, 12 ... Conductive film, 13a, 13b ... Shaft, t ... Hollow cylinder shape Roll body thickness

Claims (7)

A hollow roll body formed of a semiconductive resin and having a first open end and a second open end,
The outer peripheral surface of the roll body defines a working surface at the center and a first non-working surface and a second non-working surface at both ends thereof,
The working surface has a first end on the first open end side of the roll body and a second end on the opposite side.
A conductive coating is formed so as to at least partially cover the inner peripheral surface of the roll body,
The conductive coating is at least from a position corresponding to the first end of the working surface from a point separated from the position corresponding to the second end of the working surface by a distance corresponding to the thickness of the roll body. Covers continuously the area to the point separated inward by a distance corresponding to the thickness of the roll body,
The conductive coating, wherein the lower volume resistivity than the volume resistivity indicated semiconductive resin shows, metal, semi-conductive resin roll, which is a thin film of an alloy or a conductive metal oxide.   The semiconductive resin roll according to claim 1, wherein the roll body has a cylindrical shape, a crown shape, or an inverted crown shape.   The semiconductive resin roll according to claim 1 or 2, wherein the conductive film is formed over the entire inner peripheral surface of the roll body. 4. The semiconductive resin according to claim 1, wherein the semiconductive resin exhibits a volume resistivity of 1 × 10 ⁵ to 1 × 10 ¹² Ω · cm. ^5. roll.   The semiconductive resin roll according to any one of claims 1 to 4, further comprising: a shaft inserted into each of the first open end and the second open end.   The semiconductive resin roll according to claim 5, wherein at least one of the shafts is conductive, and the conductive shaft is in contact with the conductive film.   The semiconductive resin is a mixture of a conductive agent in a thermoplastic resin,
  The thermoplastic resin is polyvinyl chloride, polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene resin (ABS resin), acrylonitrile-styrene resin (AS resin), polymethyl methacrylate, polyvinyl alcohol, polyvinylidene chloride, polyethylene terephthalate, etc. A general-purpose plastic (general-purpose resin), polyamide, polyacetal, polycarbonate, polyphenylene ether, polybutylene terephthalate, ultrahigh molecular weight polyethylene, polyvinylidene fluoride or other engineering plastic (engineering resin), or a combination of any two or more thereof The semiconductive resin roll according to any one of claims 1 to 6.

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