JP2006258955A - Toner supply roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner supply roll in which a torque variation is hardly caused. <P>SOLUTION: The toner supply roll has a sponge elastic layer 2 formed around an outer peripheral surface of a shaft body and also has a plurality of axially extending projection streaks T<SB>1</SB>formed on the surface of the sponge elastic layer 2 peripherally at designated intervals. The projection streaks T<SB>1</SB>are sectioned in a saw-tooth shape and the tilt angle α of an oblique side 11 on a rotation-directional R side of the toner supply roll between left and right oblique sides 11 and 12 constituting each saw tooth is smaller than the tilt angle β of the other oblique side 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a toner supply roll used in electrophotographic apparatuses such as copying machines, printers, and facsimiles.

  In general, copying in an electrophotographic apparatus forms a document image as an electrostatic latent image on the surface of a photosensitive drum, forms a toner image by attaching toner to the electrostatic latent image, and transfers the toner image onto a copy sheet. This is done by fixing. The toner image is formed in this copying by supplying toner from the toner box to the surface of the developing roll and attaching the toner on the surface of the developing roll to the electrostatic latent image. The remaining toner remaining on the surface of the developing roll without being attached to the electrostatic latent image is scraped off by the toner supply roll, returned to the toner box, and then stirred by the agitator (stirrer) in the toner box. To be reused.

Accordingly, the toner supply roll is required to have a toner scraping performance for reliably scraping off the toner remaining on the surface of the developing roll in addition to a toner supplying performance for stably supplying the toner to the developing roll. Therefore, in order to improve the toner scraping performance, a plurality of ridges T ₀ extending in the axial direction may be formed at a predetermined pitch in the circumferential direction on the outer circumferential surface of the toner supply roll, as shown in FIG. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 11-52708

By the way, the toner supply roll is generally an elastic roll including a shaft body and a sponge elastic layer 2 formed on the outer peripheral surface thereof. The rough surface of the sponge elastic layer 2 causes toner supply performance and toner scraping. Demonstrate performance. In the toner supply roll of Patent Document 1, a plurality of ridges T ₀ are formed on the surface of the sponge elastic layer 2 in order to improve the toner scraping performance.

However, an actual machine (such as a copying machine) incorporating the toner supply roll disclosed in Patent Document 1 has a problem in that density unevenness occurs in an image. Therefore, as a result of repeated studies on the cause by the present inventor, it has been found that the cause is that the toner supply roll causes torque fluctuation. That is, in a state where the toner supply roll rotates while sliding on the developing roll, if the groove portion between the adjacent protruding stripes T ₀ faces the developing roll, the rotation of the toner supply roll is smooth, but the protruding stripe T _{When the 0} portion began to come into pressure contact with the developing roll, the rotation of the toner supply roll became unsmoothed, and it was determined that the toner supply roll caused torque fluctuation due to this repetition.

  The present invention has been made in view of such knowledge, and an object of the present invention is to provide a toner supply roll that hardly causes torque fluctuation.

  In order to achieve the above object, a toner supply roll of the present invention has a shaft body and a sponge elastic layer formed along the outer peripheral surface of the shaft body, and is axially formed on the surface of the sponge elastic layer. A toner supply roll in which a plurality of extending ridges are formed at a predetermined pitch in the circumferential direction, wherein the ridges are formed in a sawtooth shape in cross section, and among the left and right blade portions constituting each sawtooth, toner supply The inclination angle of the blade part on the rotation direction side of the roll is configured to be smaller than the inclination angle of the other blade parts.

  The inventor conducted further research based on the above knowledge in order to make it difficult for the toner supply roll to undergo torque fluctuation. In the course of the research, the cause of the torque fluctuation is that the surface on the rotation direction side of the toner supply roll rises too much (a steeply inclined surface) in each protrusion formed on the surface of the sponge elastic layer. I found out that there was. As a result of further research, when the surface on the rotational direction side of the toner supply roll is formed on a gently inclined surface in each ridge, the toner supply roll rotates smoothly and torque fluctuation is suppressed. The headline, the present invention has been reached.

  In the toner supply roll of the present invention, the protrusions formed on the surface of the sponge elastic layer are formed in a sawtooth shape in cross section. Of the left and right blade portions constituting each of the saw blades, the inclination angle of the blade portion on the rotation direction side of the toner supply roll is smaller than the inclination angles of the other blade portions. Therefore, the surface on the rotation direction side of the toner supply roll in each ridge is a gently inclined surface. Therefore, even if the toner supply roll rotates while sliding on the developing roll, the rotation becomes smooth. In addition, torque fluctuation of the toner supply roll can be suppressed. As a result, it is possible to obtain a high-quality image without density unevenness.

  In particular, when each of the saw blades has a substantially flat top and left and right blades extend from the substantially flat top, the toner scraping performance is set to an appropriate one in addition to suppressing torque fluctuation. It is easy to do.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of a toner supply roll of the present invention. This toner supply roll has a sponge elastic layer 2 formed on the outer peripheral surface of the shaft body 1, and a plurality of ridges T ₁ are formed on the outer peripheral surface of the sponge elastic layer 2 in parallel with the central axis of the roll. It is formed at a constant pitch in the circumferential direction. Each ridge T ₁ is formed to have a substantially uniform height and a substantially uniform width, and is continuous from one end edge to the other end edge of the sponge elastic layer 2. In the present invention, each of the ridges T ₁ is formed with a gently inclined surface on the rotation direction R side of the toner supply roll. In other words, in this embodiment, as shown in FIG. 2, each ridge T ₁ is formed in a sawtooth shape having a triangular cross section perpendicular to the axis of the toner supply roll. The two oblique sides (left and right blade portions constituting each saw tooth) 11 and 12 are inclined angles (angles formed with the bottom side) α of the oblique sides (blade portions on the rotation direction R side) 11 on the rotation direction R side of the toner supply roll α. Is formed smaller than the inclination angle (angle formed with the base 13) β of the hypotenuse (other blade portion) 12 opposite to the rotation direction R. Further, root portion of Kakutotsujo T ₁ is formed in the triangular cross section of the base 13. In FIG. 1, in order to facilitate understanding, the ridges T ₁ are illustrated in a large size and the number thereof is reduced, and in FIG. 2, the circumferential direction is illustrated in the horizontal direction.

More specifically, the triangular shape of the ridge T ₁ will be described. From the viewpoint of suppressing the torque fluctuation of the toner supply roll and optimizing the toner scraping performance, the dimension of the triangular shape is within the following range. Set to That is, as shown in FIG. 2, the length a of the base 13 having a triangular cross section is 0.5 mm or more and 3.0 mm or less, the height b is 0.1 mm or more and 1.0 mm or less, and the hypotenuse 11 on the rotation direction R side. The inclination angle α is set to 10 ° or more and 45 ° or less, and the inclination angle β of the hypotenuse 12 opposite to the rotation direction R is set to a value greater than the inclination angle α of the hypotenuse 11 on the rotation direction R side. The formation pitch c of the ridges T _1, depending on the number of ridges T _1, is set to 0.5mm or more 3.0mm or less. Each of the above dimensions is obtained by measuring the cross section of the toner supply roll with an electron microscope and measuring 10 arbitrary cross-sectional triangle shapes, and taking the average value thereof.

Then, when the toner supply roll on which the ridge T ₁ is formed is incorporated in an actual machine (copying machine or the like) and the actual machine is operated (copying or the like), as shown in FIG. It rotates while sliding in the roll G (rotation direction D). At this time, the inclined surface (the hypotenuse 11 having a triangular cross section) of each of the ridges T _{1 on} the rotation direction R side of the toner supply roll is more than the inclined surface (the hypotenuse 12 having a triangular cross section) opposite to the rotation direction R. Therefore, even if the toner supply roll rotates while sliding on the developing roll G, the rotation becomes smooth and torque fluctuation of the toner supply roll can be suppressed. In particular, when the dimension of the triangular cross section is set within the above range, the toner scraping performance can be made appropriate.

A method for manufacturing such a toner supply roll is, for example, a method in which a molding die for forming the sponge elastic layer 2 is used in which a concave groove corresponding to the ridge T ₁ is formed on the inner peripheral surface. Can be given. That is, first, a molding die having the concave groove formed on the inner peripheral surface is prepared. Then, an adhesive or the like is applied to the outer peripheral surface of the shaft body 1 as necessary, and this is coaxially installed in the hollow portion of the molding die and sealed, and then the material for forming the sponge elastic layer 2 is used. The sponge elastic layer 2 is formed by pouring and curing. As a result, the concave grooves on the inner peripheral surface of the molding die are transferred, and the ridges T ₁ are formed on the surface of the sponge elastic layer 2. Thereafter, the mold is removed. In this way, the toner supply roll can be produced.

  Next, materials for forming the shaft body 1 and the sponge elastic layer 2 constituting the toner supply roll of the present invention will be described.

  The shaft body 1 may be solid or hollow. Examples of the material for forming the shaft body include metal materials such as iron, stainless steel, and aluminum, or polyacetal (POM), acrylonitrile butadiene styrene copolymer (ABS), polycarbonate, and nylon. Such as plastic. And you may apply | coat an adhesive agent, a primer, etc. to the outer peripheral surface of the said shaft body 1 as needed.

  As the material for forming the sponge elastic layer 2, a polyol component and an isocyanate component used in the production of a flexible polyurethane foam are used. Examples of the polyol component include polyether polyol, polyester polyol, polymer polyol and the like, and these are used alone or in combination of two or more. The isocyanate component is not particularly limited as long as it is a polyisocyanate having two or more functions. For example, 2,4- (or 2,6-) tolylene diisocyanate (TDI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate. (NDI), xylylene diisocyanate (XDI), 4,4'-diphenylmethane diisocyanate (MDI), carbodiimide-modified MDI, polymethylene polyphenyl isocyanate, polymeric polyisocyanate, and the like. These may be used alone or in combination of two or more. Used. If necessary, in addition to the polyol component and the isocyanate component, a crosslinking agent, a foaming agent (water, low-boiling substances, gas bodies, etc.), a surfactant, a catalyst, a flame retardant, a filler, and a conductivity-imparting agent. Further, an antistatic agent or the like may be appropriately blended. The sponge elastic layer 2 is not limited to the flexible polyurethane foam, but may be other foamed rubber.

4 and 5 show a second embodiment of the toner supply roll of the present invention. In this toner supply roll, the cross-sectional shape of the ridge T ₂ formed on the outer peripheral surface of the sponge elastic layer 2 is formed in a sawtooth shape having a non-isopodal trapezoidal shape, and the substantially flat shape having a cross-sectional non-isopodal trapezoidal shape. Two hypotenuses (left and right blade portions constituting each saw tooth) 11 and 12 extend from the top portion 14. Further, the length d of the substantially flat top portion 14 is formed to be smaller than the length of the bottom side 13, and from the viewpoint of suppressing the torque fluctuation of the toner supply roll and making the toner scraping performance appropriate, it is 0.5 mm or less. Is set. Other than that, it is the same as the toner supply roll shown in FIGS. 1 and 2, and the same reference numerals are given to the same parts. This toner supply roll also has the same operations and effects as the toner supply roll shown in FIGS.

FIG. 6 shows a third embodiment of the toner supply roll of the present invention. In the toner supply roll, the substantially flat top portion 14 inclines toward the rotation direction R side of the toner supply roll in the cross-section isosceles trapezoidal shape of the protrusion T ₂ of the toner supply roll shown in FIGS. In addition, the ridge T ₃ is formed. Other than that, it is the same as the toner supply roll shown in FIGS. 4 and 5, and the same reference numerals are given to the same parts. This toner supply roll also has the same operations and effects as the toner supply roll shown in FIGS.

In each of the above embodiments, in the protrusions T ₁ , T ₂ , T ₃ of the toner supply roll, the root portion of the inclined surface (slope side 11) on the rotation direction R side of the toner supply roll is opposite to the rotation direction R. Although the base portion of the inclined surface (the hypotenuse 12) is illustrated apart from each other, the positions of the two may be matched. For example, for the ridges T ₂ shown in FIG. 5, as shown in FIG. 7, it may be to match the position of the two.

  Next, examples will be described together with conventional examples.

  A toner supply roll (see FIGS. 1 and 2) in which the cross-sectional shape of the ridges was formed in a triangular shape using a shaft body, a sponge elastic layer forming material, and the like as described below. For the formation of the sponge elastic layer, a mold having a concave groove corresponding to the ridge was formed on the inner peripheral surface.

[Shaft]
A SUM22 solid cylindrical shaft body having a diameter of 5 mm was prepared.

[Preparation of sponge elastic layer forming material]
90 parts by weight of polyether polyol (Mitsui Chemicals, EP-828, OH number = 28), 10 parts by weight of polymer polyol (Mitsui Chemicals, POP-31-28, OH number = 28), 2 parts by weight of diethanolamine, Silicon foam stabilizer (manufactured by Nihon Unicar Co., Ltd., L-5309) 3 parts by weight, water 2 parts by weight, tertiary amine catalyst (manufactured by Kao Corporation, Kaorizer No. 31) 0.5 part by weight, tertiary amine catalyst ( Tosoh Corporation, Toyocat HX-35) 0.1 parts by weight, DBTDL 0.1 parts by weight, and isocyanate (Sumitomo Bayer Urethane Co., Ltd., Sumijoule VT-80, NCO% = 45) 30.5 parts by weight Thus, a material for forming the sponge elastic layer was prepared.

[Production of toner supply roll]
A shaft is coaxially set on the molding die, and the forming material for the sponge elastic layer is filled in the molding space. Then, the molding die is placed in an oven and foamed and cured (60 ° C. × 30 minutes). Thus, a sponge elastic layer (outer diameter 16 mm) was formed on the outer peripheral surface of the shaft body. On the outer peripheral surface of the sponge elastic layer, a plurality of ridges having a non-isosceles trapezoidal cross section were formed at a predetermined pitch (1.3 mm) in the circumferential direction parallel to the central axis of the roll. The dimensions of each ridge are: the length of the triangular base is 1.2 mm, the height is 0.3 mm, the inclination angle of the hypotenuse on the rotation direction side is 13 °, and the inclination angle of the hypotenuse on the opposite side to the rotation direction is 90 °. °. In addition, each dimension of the said protruding item | line was measured about 10 arbitrary triangular shapes, seeing the cross section of the toner supply roll with the electron microscope, and took those average values. The same applies to the following dimensions.

  In Example 1 described above, the dimensions of the ridges formed on the outer peripheral surface of the sponge elastic layer were changed as follows by changing the dimensions of the concave grooves formed on the inner peripheral surface of the molding die. That is, the formation pitch of the ridges is 1.3 mm, the length of the triangular base is 1.3 mm, the height is 0.3 mm, the inclination angle of the hypotenuse on the rotation direction side is 15 °, and the hypotenuse on the opposite side to the rotation direction The inclination angle was set to 60 °. Other than that was carried out similarly to the said Example 1.

  In Example 1 above, the toner supply roll in which the cross-sectional shape of the ridges is formed into a non-isosceles trapezoid by changing the shape and dimensions of the grooves formed on the inner peripheral surface of the molding die (FIG. 4). And FIG. 5). That is, the formation pitch of the ridges is 1.3 mm, the length of the substantially flat top portion of the non-isosceles trapezoidal shape is 0.5 mm, the length of the base is 1.0 mm, the height is 0.3 mm, and the rotation direction side The inclination angle of the hypotenuse was 30 °, and the inclination angle of the hypotenuse opposite to the rotation direction was 90 °. Other than that was carried out similarly to the said Example 1.

  In Example 3 above, the dimensions of the ridges formed on the outer peripheral surface of the sponge elastic layer were changed as follows by changing the dimensions of the concave grooves formed on the inner peripheral surface of the molding die. In other words, the formation pitch of the ridges is 1.5 mm, the length of the substantially flat top portion of the non-isosceles trapezoidal shape is 0.5 mm, the length of the base is 1.5 mm, the height is 0.3 mm, the rotation direction side The inclination angle of the hypotenuse was 16.5 °, and the inclination angle of the hypotenuse opposite to the rotation direction was 90 °. Other than that was carried out similarly to the said Example 3.

[Conventional example 1]
In Example 1 described above, a toner supply roll in which the cross-sectional shape of the ridges was formed into an isosceles triangle was produced by changing the dimensions of the grooves formed on the inner peripheral surface of the molding die. That is, the length of the base of the isosceles triangle shape was 1.0 mm and the height was 0.5 mm (the inclination angles of the two hypotenuses were both 45 °). Other than that, it was the same as in Example 1 above.

[Conventional example 2]
In Example 3 above, the toner supply roll (see FIG. 8) in which the cross-sectional shape of the ridges is formed into an isosceles trapezoid by changing the dimensions of the grooves formed on the inner peripheral surface of the molding die. Produced. That is, the length of the upper base of the isosceles trapezoid was 0.8 mm, the length of the base was 1.0 mm, and the height was 0.3 mm (the inclination angles of the two hypotenuses were both 75 °). Other than that was carried out similarly to the said Example 3.

[Presence or absence of uneven density]
The toner supply rolls of Examples 1 to 4 and Conventional Examples 1 and 2 obtained in this way are incorporated into a toner cartridge, and the toner cartridge is set in a color laser printer (Color Laser Jet 4500, manufactured by Hewlett-Packard Company). Then, a halftone image was imaged in an environment of 15 ° C. and 10% (humidity). And the presence or absence of density unevenness was visually confirmed about the image of the image extraction. As a result, those having no horizontal stripe-like density unevenness due to torque fluctuation were evaluated as ◯, and those having density unevenness were evaluated as ×, and are also shown in Table 1 below.

[Toner scraping performance]
About the halftone image of the said image appearance, the presence or absence of the whole density unevenness (density unevenness which is not a horizontal stripe shape) of the image was confirmed visually. As a result, the case where there was no density unevenness was evaluated as ◯, the case where it could be confirmed a little, Δ, the case where it could be clearly confirmed was evaluated as X, and the results were also shown in Table 1 below.

[Toner transportability]
Also, a solid black image was imaged under an environment of 15 ° C. and 10% (humidity). And the image density was measured using the reflection densitometer (product made from a Macbeth company) about the image of the image start. As a result, those having an image density of 1.1 or more were evaluated as “good” as being excellent in toner transportability, and are listed together in Table 1 below.

  As a result, the image obtained by the color laser printer incorporating the toner supply rolls of Examples 1 to 4 has no density unevenness due to torque fluctuation, and the image obtained by the color laser printer incorporating the toner supply rolls of Conventional Examples 1 and 2 is not included in the images. There was uneven density. Further, the toner scraping performance of the toner supply roll of Conventional Example 1 was slightly inferior to that of the other. The toner transportability was good for all of the toner supply rolls of Examples 1 to 4 and Conventional Examples 1 and 2.

FIG. 3 is a perspective view schematically showing a first embodiment of a toner supply roll of the present invention. FIG. 4 is an enlarged side view schematically showing a surface portion of the toner supply roll. FIG. 6 is an explanatory diagram schematically showing an operating state of the toner supply roll. FIG. 6 is a perspective view schematically showing a second embodiment of a toner supply roll of the present invention. FIG. 4 is an enlarged side view schematically showing a surface portion of the toner supply roll. FIG. 6 is an enlarged side view of a surface portion schematically showing a third embodiment of a toner supply roll of the present invention. It is an enlarged side view of the surface part which shows the modification of the said 2nd Embodiment. FIG. 6 is an enlarged side view schematically showing a surface portion of a conventional toner supply roll.

Explanation of symbols

2 Sponge elastic layer 11, 12 hypotenuse R rotation direction T ₁ convex stripe α, β inclination angle

Claims (2)

  A shaft body and a sponge elastic layer formed along the outer peripheral surface of the shaft body, and a plurality of protrusions extending in the axial direction are formed on the surface of the sponge elastic layer at a predetermined pitch in the circumferential direction. The toner supply roll, wherein the ridges are formed in a sawtooth shape in cross section, and the inclination angle of the blade part on the rotation direction side of the toner supply roll among the left and right blade parts constituting each of the saw teeth is other blades A toner supply roll, wherein the toner supply roll is smaller than an inclination angle of the portion.   The toner supply roll according to claim 1, wherein each of the saw teeth has a substantially flat top portion, and left and right blade portions extend from the substantially flat top portion.

Images