JP2004233817A - Sponge roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sponge roll which has high productivity and is adaptable to even a complicated arrangement (pattern) of projection streaks on the surface. <P>SOLUTION: On the surface of a sponge elastic layer 2 formed around the outer surface of a shaft 1, a plurality of projection streaks 3 are formed extending nearly along the axis with specified intervals in the circumferential direction and those projection streaks 3 are formed of photosetting resin. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sponge roll such as a toner supply roll used in an electrophotographic apparatus such as a copying machine, a printer, and a facsimile.
[0002]
[Prior art]
Generally, in copying in an electrophotographic apparatus, an original image is formed as an electrostatic latent image on the surface of a photosensitive drum, a toner is attached to the electrostatic latent image to form a toner image, and the toner image is transferred onto copy paper. It is performed by fixing. The formation of the toner image in this copying is performed by supplying a toner from a toner box to a surface of a developing roll from a toner box, and attaching the toner on the surface of the developing roll to the electrostatic latent image. The residual 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. And used for reuse.
[0003]
Therefore, the toner supply roll is required to have not only a toner supply performance of stably supplying the toner to the development roll, but also a toner scraping performance of reliably scraping excess toner on the surface of the development roll. In order to improve the toner scraping performance, a plurality of ridges extending in the axial direction are formed on the surface of the toner supply roll at a predetermined pitch in the circumferential direction. 1).
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. H11-38749
[Problems to be solved by the invention]
By the way, the toner supply roll is generally composed of a shaft body and a sponge elastic layer made of urethane foam molded on the outer peripheral surface, and the toner supply performance is exhibited by the rough surface of the sponge elastic layer surface. I have. Then, in order to further improve the toner scraping performance and the like, the ridges are formed on the surface of the sponge elastic layer as described above. The methods for forming the ridges are as follows: The method 2) can be considered.
(1) After forming the sponge elastic layer on the outer peripheral surface of the shaft body, a plurality of grooves extending in the axial direction are formed on the surface of the sponge elastic layer at a predetermined pitch in the circumferential direction by cutting or the like, so that adjacent grooves are formed. The above-mentioned ridges are developed between the matching grooves.
{Circle around (2)} As a molding die for molding the sponge elastic layer, a special molding die in which a groove corresponding to the above-mentioned ridge is formed on the inner peripheral surface is used.
[0006]
However, in the above method (1), the sponge elastic layer itself has a low hardness and is deformed when performing a cutting process or the like, so that it is difficult to perform a process such as a cutting process. Therefore, it is difficult to maintain the processing accuracy even if the processing is forcibly performed. In addition, the processing time is prolonged, and the productivity is reduced. Further, in the method (2), it takes time and cost to produce a molding die, and because of the limitations of the processing technology of the molding die and the limitations of workability at the time of molding, the feasible ridge arrangement ( Pattern) is limited, and a desired toner scraping performance is hardly obtained.
[0007]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a sponge roll which has high productivity and can cope with a complicated arrangement of convex ridges (pattern) on the surface.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the sponge roll of the present invention has a shaft and a sponge elastic layer formed along the outer peripheral surface of the shaft, and the surface of the sponge elastic layer substantially in the axial direction. A plurality of extending ridges are sponge rolls formed at a predetermined pitch in the circumferential direction, and the ridges are made of a photocurable resin.
[0009]
The inventor of the present invention has conducted intensive studies on a method of forming the above-mentioned ridges so that the sponge roll has high productivity and can cope with complicated arrangements (patterns) of ridges on the surface. As a result of the research, if the ridge is formed of a photo-curable resin, the surface of the sponge elastic layer does not need to be cut or the like, and the ridge corresponds to the molding die for forming the sponge elastic layer. It has been found that the intended purpose can be achieved without forming and processing a groove to be formed, and the present invention has been achieved. In the present invention, “substantially axial direction” means not only a precise axial direction but also a direction that forms an angle of 45 ° or less with the axial direction.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0011]
FIG. 1 shows an embodiment of the sponge roll of the present invention. In this sponge roll, a sponge elastic layer 2 made of urethane foam is formed on the outer peripheral surface of a shaft body 1, and a plurality of ridges 3 extending in the axial direction on the surface of the sponge elastic layer 2 have a predetermined shape in the circumferential direction. It is formed at a pitch P (see FIG. 2). The ridge 3 is made of a photocurable resin. Note that, in FIG. 1, to facilitate understanding, the above-mentioned ridges 3 are illustrated in a large size, and the number of the ridges 3 is reduced.
[0012]
As described above, when the sponge roll in which the ridges 3 are made of a photocurable resin is used as a toner supply roll, the ridges 3 are harder than the sponge elastic layer 2, and the toner remaining on the surface of the developing roll is removed. It can be more reliably scraped. Further, the slidability with other members such as the developing roll is improved, the rotation of the toner supply roll becomes smooth, and the toner supply becomes more stable. As a result, image quality can be further improved.
[0013]
When the sponge roll is used as a cleaning roll, the scraping property and the slidability are improved, so that the cleaning effect is exerted even when the pressure applied to the member to be cleaned is reduced, and the stress on the member to be cleaned is reduced. And the load on the driving device of the cleaning mechanism can be reduced. In addition, when the sponge roll is used as a paper feed (feed, transport) roll, the nip width is increased and the slidability is stabilized, so that there is an operation and effect that stable paper feed is possible.
[0014]
In the sponge roll, it is possible to easily optimize the frictional force acting between the sponge roll and the contact object that comes into contact with the sponge roll by adjusting the shape, pitch, and the like of the ridges 3. it can.
[0015]
More specifically, the shaft body 1 is not particularly limited, and may be a metal core made of a solid metal body, a metal cylindrical body hollowed out inside, or the like. Examples of the material include stainless steel, aluminum, and iron plated.
[0016]
When the sponge roll is used as a toner supply roll, as shown in FIG. 2, it is preferable that the height H of the protrusion 3 on the surface of the sponge elastic layer 2 is set in a range of 20 to 3000 μm. . The reason is that if the height H of the ridges 3 is out of the above range, the toner scraping performance tends to be inferior. Further, it is preferable that the width of the protrusions 3 is set in the range of 100 to 2000 μm and the pitch P in the circumferential direction is set in the range of 300 to 3000 μm from the viewpoint of further improving the toner scraping performance. Note that FIG. 2 shows a partially enlarged cross section of the surface portion of the sponge roll to facilitate understanding.
[0017]
Most of the cells 4 on the surface of the sponge elastic layer 2 are open to the surface of the sponge elastic layer 2, and the average opening diameter is preferably set in the range of 100 to 800 µm. That is, if the average opening diameter is less than 100 μm, the toner that has entered the cell 4 tends to be hard to come out, and if it exceeds 800 μm, the toner supply amount tends to decrease, and in any case, the image quality may deteriorate. Because there is. The average cell diameter of the cells 4 in the sponge elastic layer 2 is preferably equal to or larger than the average opening diameter and set in a range of 100 to 1000 μm. That is, when the average cell diameter is less than 100 μm, the toner tends to be easily clogged in the cell 4, and when the average cell diameter is more than 1000 μm, the amount of toner entering the cell 4 tends to be too large, and in any case, the image quality is poor. This is because there is a risk of deterioration. Further, in the sponge elastic layer 2, the opening 6 having the above-mentioned average opening diameter is formed in all or a part of the cell film 5 existing at the boundary between the adjacent cells 4 in that the deterioration of the toner can be suppressed. It is preferable that the cells 4 have an open-cell structure (see FIG. 2) in which all or some of the cells 4 are connected in a three-dimensional manner.
[0018]
As a material for forming the above-mentioned sponge elastic layer 2, a polyol component and an isocyanate component used in the production of a normal flexible polyurethane foam are used. Examples of the polyol component include a polyether polyol, a polyester polyol, a polymer polyol, and the like. These may be used alone or in combination of two or more. The isocyanate component is not particularly limited as long as it is a polyfunctional isocyanate having two or more functional groups. (NDI), xylylene diisocyanate (XDI), 4,4'-diphenylmethane diisocyanate (MDI), modified carbodiimide MDI, polymethylene polyphenyl isocyanate, polymeric polyisocyanate, and the like, alone or in combination of two or more. Used.
[0019]
In addition, as necessary, in addition to the polyol component and the isocyanate component, the raw materials described above include a crosslinking agent, a foaming agent (water, a low-boiling substance, a gaseous substance, etc.), a surfactant, a catalyst, a flame retardant, a filler, A conductivity imparting agent, an antistatic agent and the like may be appropriately blended.
[0020]
Examples of the photo-curable resin which is a material for forming the above-mentioned ridges 3 include those obtained by adding a photopolymerization initiator and a photosensitizer to an unsaturated polyester resin or polybutadiene, or a pre-polymer such as acryl, urethane, epoxy, or the like. Examples thereof include those obtained by adding a photosensitizer or the like to an unsaturated resin having an unsaturated group introduced into a polymer. Specifically, Aronix (manufactured by Toagosei Co., Ltd.), APR (manufactured by Asahi Kasei Co., Ltd.), Hitaroid (Hitachi Chemical Co., Ltd.) And the like). Each of the photocurable resins is cured in a short time within a range of 1 second to 1 minute by irradiation with light such as ultraviolet rays. Note that the photo-curable resin is preferably a non-solvent. This is because the sponge elastic layer 2 swells when a solvent is used.
[0021]
The photocurable resin may optionally contain a conductivity-imparting agent, an antistatic agent, and the like, as necessary.
[0022]
Next, a method for manufacturing the toner supply roll will be described. This toner supply roll can be manufactured, for example, as follows. That is, first, the mold shown in FIG. 3 is prepared. This molding die includes a cylindrical mold 11 having a length substantially equal to the axial length of the sponge elastic layer 2 (see FIG. 1) of the toner supply roll, and caps 12 for closing both ends of the cylindrical mold 11. ing. Also, in this molding die, when the shaft 1 is loaded into the cylindrical mold 11 and both ends of the cylindrical mold 11 are closed with caps 12, the shaft 1 is supported coaxially with the cylindrical mold 11 by the caps 12, In the cylindrical mold 11, a molding cavity 13 for giving a final roll shape of a target toner supply roll is formed. Next, the shaft body 1 is loaded into the cylindrical mold 11 of the above-mentioned molding die, and both ends of the cylindrical mold 11 are closed with caps 12, and then the material for forming the sponge elastic layer 2 is injected into the molding cavity 13 to be formed. , Foaming and curing. Next, after the mold is released, a photocurable resin is applied by printing or the like to a portion of the surface of the sponge elastic layer 2 where the ridge 3 is to be formed. Then, the light curable resin portion is irradiated with light such as ultraviolet light using a lamp such as an ultraviolet lamp. As a result, the photocurable resin portion is cured to form the ridges 3.
[0023]
In the formation of the sponge elastic layer 2 in the above-mentioned mold, when the expansion ratio is set to about 5 to 20 times, the average opening diameter of the cells 4 that are open on the surface of the sponge elastic layer 2 falls within the range of 100 to 800 μm. It can be formed, and the average cell diameter of the cells 4 in the sponge elastic layer 2 can be formed in the range of 100 to 1000 μm. These average opening diameter and average cell diameter can be adjusted by changing the expansion ratio.
[0024]
Further, after the demolding, a high-pressure gas (a gas such as air or nitrogen) is jetted to the sponge elastic layer 2 using a nozzle or the like while rotating the toner supply roll about the shaft body 1. Is diffused into the sponge elastic layer 2 by the resistance of the shaft body 1, and the opening action of the cell film 5 is remarkably exhibited. As a result, the opening 6 is formed in the cell film 5 existing at the boundary between the adjacent cells 4. . The degree of formation of the opening 6 can be adjusted by changing the pressure of the gas to be injected.
[0025]
The method for forming the ridges 3 is not particularly limited, but includes a coating method such as a printing method, a method using an ink jet, and a normal spraying method using a spray nozzle or the like. For example, the printing method uses a printing roll 21 as shown in FIG. That is, a groove 22 corresponding to the above-mentioned ridge 3 is formed on the surface of the printing roll 21, and the printing roll 21 and the toner supply roll are arranged in parallel and in contact with each other. Further, the printing roll 21 is configured to rotate, and the rotation causes the toner supply roll to rotate together with the printing roll 21. A part of the print roll 21 is immersed in the liquid photocurable resin 3a, and the photocurable resin 3a filled in the groove 22 on the surface of the print roll 21 is printed on the surface of the toner supply roll. It has become.
[0026]
As described above, according to the sponge roll of the embodiment, since the ridges 3 made of a photocurable resin are formed on the surface of the sponge elastic layer 2, the toner supply performance and the toner scraping performance are excellent. It can function as a toner supply roll. Further, it can function as a cleaning roll having excellent cleaning properties and a paper feeding / transporting roll having excellent paper transport properties. In the production of the sponge roll, since the ridges 3 are formed of a photocurable resin, it is not necessary to perform a difficult process such as forming the ridges by cutting the sponge elastic layer. Moreover, the hardening of the ridges 3 by the photo-curing resin can be performed in a short time. As a result, the sponge roll of the above embodiment can improve productivity. In addition, when the ridges 3 are formed of a photocurable resin, it is not necessary to use a special molding die in which grooves corresponding to the ridges are formed, so that the time and cost for producing the molding die are reduced. be able to. Further, when a photocurable resin is applied to form the ridges 3, a printing method or a method using an ink jet is used, so that the degree of freedom in designing the arrangement (pattern) of the ridges 3 is determined. And the arrangement (pattern) of the ridges 3 can be complicated.
[0027]
FIG. 5 shows another embodiment of the sponge roll of the present invention. In this embodiment, the arrangement (pattern) of the ridges 3 is complicated. That is, the ridge 3 is formed in a spiral shape, and the extending direction of the ridge 3 forms a predetermined angle θ with the axial direction indicated by the dashed line A. Is preferably 45 ° or less. If it exceeds 45 °, the toner scraping performance tends to be inferior. Other parts are the same as those of the above-described embodiment, and the same parts are denoted by the same reference numerals. The arrangement (pattern) of the ridges 3 makes it possible to easily set the toner scraping performance to a desired performance.
[0028]
FIG. 6 shows still another embodiment of the sponge roll of the present invention. Also in this embodiment, the arrangement (pattern) of the ridges 3 is complicated. That is, the outer peripheral surface of the sponge roll is virtually divided into four regions in the axial direction, and a plurality of short ridges 3 are formed in each of the regions so as to be staggered. Other parts are the same as those of the above-described embodiment, and the same parts are denoted by the same reference numerals. In this embodiment, the same operation and effect as described above are achieved, and the toner scraping performance is set to a desired performance by changing the height, distribution density, and the like of the ridges 3 for each region. Will be able to
[0029]
Next, examples will be described together with comparative examples.
[0030]
Embodiment 1
The sponge roll shown in FIG. 1 was produced as described above. That is, in this sponge roll, a round rod made of SUM22 having a diameter of 5 mm was used as the shaft body 1, the sponge elastic layer 2 had an open-cell structure, and the outer diameter was 16 mm. The average opening diameter of the cells 4 in the surface portion of the sponge elastic layer 2 was 400 μm, and the average cell diameter of the cells 4 in the sponge elastic layer 2 was 600 μm. The height H of the ridges 3 on the surface of the sponge elastic layer 2 was 200 μm, the width W was 200 μm, and the pitch P in the circumferential direction was 800 μm.
[0031]
In the production of this sponge roll, the material for forming the sponge elastic layer 2 was prepared as follows. That is, 90 parts by weight of polyether polyol (Mitsui Chemicals, EP-828, OH value = 28), 10 parts by weight of polymer polyol (Mitsui Chemicals, POP-31-28, OH number = 28), diethanolamine 2 parts by weight, 3 parts by weight of a silicone foam stabilizer (manufactured by Nippon Unicar, L-5309), 2 parts by weight of water, and 0.5 part by weight of a tertiary amine catalyst (Kaolyzer No. 31 manufactured by Kao Corporation) Parts, tertiary amine catalyst (Tosoh Corporation, Toyocat HX-35) 0.1 part by weight, DBTDL 0.1 parts by weight, and isocyanate (Sumitomo Bayer Urethane Co., Ltd., Sumidur VT-80, NCO%) = 45) was blended in an amount of 30.5 parts by weight to prepare a material for forming the sponge elastic layer 2.
[0032]
The projections 3 are formed by using Aronix (M-113, manufactured by Toagosei Co., Ltd.) as a photo-curable resin, printing using a printing roll 21, and then using an ultraviolet lamp UB013-2A / BM type (eye graphic). UV light for 30 seconds to cure the resin.
[0033]
[Comparative Example 1]
In Example 1 described above, Comparative Example 1 was formed without forming the ridges 3.
[0034]
Each of the sponge rolls of Example 1 and Comparative Example 1 thus obtained was incorporated into a toner cartridge as a toner supply roll, and the toner cartridge was allowed to stand in a low-temperature and low-humidity (15 ° C. × 10%) environment for 7 days. After that, it was set on a color laser printer, and an image was displayed. For this image output, a toner having an average particle diameter of 7 to 10 μm was used. Then, the toner scraping performance was evaluated.
[0035]
[Toner scraping performance]
With respect to the image thus obtained, the presence or absence of streaks and uneven density was visually confirmed. As a result, it can be evaluated that the image obtained by the color laser printer incorporating the sponge roll of Example 1 has no streaks or uneven density and has excellent toner scraping performance. On the other hand, an image obtained by the color laser printer incorporating the sponge roll of Comparative Example 1 has slight streaks and uneven density, and can be evaluated as having slightly poor toner scraping performance.
[0036]
【The invention's effect】
As described above, according to the sponge roll of the present invention, since the plurality of ridges extending substantially in the axial direction are formed of the photocurable resin on the surface of the sponge elastic layer, the sponge is formed to form the ridges. Difficult processing such as cutting the elastic layer is not required, and the hardening of the ridges by the photocurable resin can be performed in a short time. As a result, according to the sponge roll of the present invention, productivity can be significantly improved. In addition, by forming the above-mentioned ridges with a photo-curable resin, it is not necessary to use a special molding die in which a groove corresponding to the ridge is formed, so that the time and cost for producing the molding die are reduced. can do. Further, when a photocurable resin is applied to form the ridges, a printing method or a method using an inkjet is used, so that the arrangement (pattern) of the ridges can be easily changed as necessary. Since it can be changed and can also handle complicated arrangements (patterns), the degree of freedom of design is greatly increased.
[0037]
In particular, in the present invention, when the height of the ridge is in the range of 20 to 3000 μm, it can function as a toner supply roll having more excellent toner scraping performance.
[0038]
Further, in the present invention, when the circumferential pitch of the ridges is in the range of 300 to 3000 μm, the ridges can function as a toner supply roll with improved toner scraping performance.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a sponge roll of the present invention.
FIG. 2 is a partially enlarged sectional view of a surface portion of the sponge roll.
FIG. 3 is a cross-sectional view showing a forming die used for forming a sponge elastic layer of the sponge roll.
FIG. 4 is an explanatory view showing a method of printing a photo-curable resin for forming the above-mentioned ridges.
FIG. 5 is a perspective view showing another embodiment of the sponge roll of the present invention.
FIG. 6 is a perspective view showing still another embodiment of the sponge roll of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shaft body 2 Sponge elastic layer 3 Protrusion

Claims (3)

A shaft and a sponge elastic layer formed along the outer peripheral surface of the shaft, and a plurality of ridges extending substantially in the axial direction on the surface of the sponge elastic layer are formed at a predetermined pitch in the circumferential direction. A sponge roll, wherein the ridges are made of a photocurable resin. The sponge roll according to claim 1, wherein the height of the ridge is in a range of 20 to 3000 µm. The sponge roll according to claim 2, wherein a circumferential pitch of the ridge is in a range of 300 to 3000 μm.

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