JP2014056075A - Toner carrier, one-component developing device using the toner carrier, process cartridge, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner carrier that has a surface shape capable of preventing adhesion of toner to a regulating member in a one-component developing method and/or filming on the toner carrier, and resetting to the original surface shape even if the toner adhesion occurs; and a manufacturing method of the toner carrier.SOLUTION: A toner carrier for a one-component developing device has a toner carrier that conveys toner, and a regulating member that regulates the amount of toner conveyed on the surface of the toner carrier. The toner carrier has an elastic layer; the elastic layer has polygonal-shape convex parts having the apex angle on the upstream side in a toner conveyance direction in the number of 1000 or more and 10000 or less per 1 mm; the convex part has sides forming the apex angle with the length of 3 μm or more and 10 μm or less; and the apex angle is in the range of 10° to 60°.

Description

  The present invention relates to a toner carrier, a one-component developing device using the toner carrier, a process cartridge, and an image forming method.

Electrophotographic development methods can be broadly classified into dry development methods and wet development methods, and dry development methods are further classified into one-component development methods and two-component development methods.

The two-component development system uses a developer in which toner and magnetic particles called a carrier are mixed at an appropriate weight ratio in order to impart an electric charge to the toner. In this method, toner is electrostatically attached to a photoreceptor.
On the other hand, the one-component development method is a method in which an appropriate charge amount is directly applied to the toner itself without using a carrier, which is advantageous for downsizing of the apparatus.

However, the one-component development method is a development method that applies a great deal of stress to the toner because the toner is charged by rubbing the toner strongly at the regulating portion, and is often incompatible with the low-temperature fixing toner that is a recent trend, In particular, toner sticking and toner filming at the restriction portion tend to occur more easily.

That is, in the one-component developing system, the toner is rubbed strongly at the restriction portion, so that the temperature near the restriction portion rises, and the toner components such as wax and fixing aid soften and adhere to the restriction portion. This is the starting point (binder), and the toner particles and external additives adhere to the regulating blade and the developing roller and spread due to stress, so that the regulating blade is fixed or the developing roller is filmed. It is thought to occur.

As a result, because the toner on the regulating blade is stuck, the passage of the toner is hindered, so that a vertical white streak image is generated. Will happen.

Here, the ease of toner flow at the restricting portion and the surface shape of the developing roller have the following relationship.
For example, when the toner carrier has a surface shape having a step in the circumferential direction, the toner or toner component tends to stay in the recess of the step, is stressed, and easily adheres to the developing roller, and the toner flow is smooth. When a non-existing portion is generated, the toner is filmed on the developing roller starting from that portion. Further, even when the surface of the toner carrier is smooth, the toner stays in the restricting portion, so that the toner adheres to the restricting blade.
In other words, the toner flow must always be smooth, and when toner stays, the toner tends to adhere to the regulating blade and the developing roller.

  Japanese Patent Application Laid-Open No. 2005-212372 discloses a surface roughness by irradiating an unvulcanized rubber roller with ultraviolet rays or an electron beam while pressing a heated member having a smooth or uneven surface shape. Although it has been disclosed that a uniform developing roller can provide a good image, there is no disclosure of the specific shape of the developing roller surface, and toner filming occurs when low-temperature fixing toner is used.

  Controlling the surface shape of the developer carrier is disclosed in Japanese Patent Application Laid-Open No. 2007-127903, Japanese Patent No. 4628932, and Japanese Patent Application Laid-Open No. 2009-3248. These relate to the two-component development method.

When forming a complex uneven shape on the surface of a developer carrying member, a metal roller or a thermosetting resin rubber roller is mainly used because of ease of processing, but it is a low-priced vulcanized rubber roller. Since a vulcanization process is required and manufacturing restrictions are imposed, it is limited to the application of vertical stripes or horizontal stripes by polishing, or the formation of convex portions by surface exposure of fillers, and the toner transportability over a long period of time. There is a problem that it is difficult to obtain a surface shape excellent in resetting property when toner sticking occurs, and it is difficult to use a toner having low-temperature fixability in a one-component developing method.

The present invention relates to a toner carrier having a surface shape that can prevent toner from adhering to a regulating portion of a one-component development method and / or filming to a toner carrier and can be reset even if toner adhering occurs. An object is to provide a method for producing a toner carrier.

  The inventors of the present invention have formed a fine convex portion having a toner particle size on the surface of the toner carrier, so that the toner is hardly caught on the surface of the toner carrier, and between the convex portions on the surface of the toner carrier. The present invention was completed by finding that toner particles flow smoothly without retaining toner particles in the recesses, and that toner staying in the restricting portion can be scraped off by the protrusions and can be reset even if toner sticking occurs. It came to do.

That is, the said subject is solved by following (1)-(9) of this invention.
(1) “A toner carrier for a one-component developing device having a toner carrier for conveying toner and a regulating member for regulating the toner conveyance amount on the surface of the toner carrier, the toner carrier having an elastic layer. The elastic layer has 1000 to 10,000 polygonal convex portions per 1 mm ² having an apex angle on the upstream side in the toner conveying direction, and the convex portion has a side length forming the apex angle. 3 to 10 μm and the apex angle is 10 ° to 60 ° ”,
(2) “The toner carrier according to (1) above, wherein the height of the convex portion is 3 μm or more and 10 μm or less”,
(3) “The toner carrier according to (1) or (2) above, wherein the elastic layer is made of vulcanized rubber”,
(4) “The vulcanized rubber is an epichlorohydrin rubber selected from epichlorohydrin-ethylene oxide copolymer and epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer. The toner carrying member according to item (3) above,
(5) "The toner carrier according to any one of (1) to (4) above, wherein the surface shape of the developing roller is formed by a laser ablation method";
(6) “The toner carrier according to (5) above, wherein the laser processing apparatus used in the laser ablation method is an excimer laser using a rare gas KrF”.
(7) “A one-component developing device having a toner carrier for conveying toner and a regulating member for regulating the amount of toner on the surface of the toner carrier, wherein the toner carrier comprises the above-mentioned items (1) to (1). A one-component developing device characterized by being a toner carrier according to any one of (6), "
(8) “Process cartridge having the toner carrier according to any one of (1) to (6)”,
(9) “An image forming method using the toner carrier according to any one of (1) to (6)”.

  As will be understood from the following detailed and specific description, according to the present invention, for a long period of time, the toner is fixed to the regulating portion and / or filmed on the toner carrier in the one-component development method. As a result, a toner having excellent low-temperature fixability can be used in the one-component developing method, and an energy-saving and small-sized image forming apparatus can be obtained.

It is a figure which shows the some example of the shape of the polygon convex part of the toner carrier surface of this invention. It is a figure which shows the vertex angle of a polygon. FIG. 5 is a diagram illustrating an example of a state of occurrence of toner fixation and filming when a groove in the toner conveyance direction is formed on the surface of a toner carrier. FIG. 6 is a diagram illustrating an example of a state of occurrence of toner fixation and filming when grooves perpendicular to the toner conveyance direction are formed on the surface of the toner carrier. 1 is a schematic diagram illustrating an example of a one-component image forming apparatus of the present invention. It is the schematic which shows an example of the process cartridge of this invention.

The toner carrier of the present invention will be described in detail.
The toner carrier of the present invention has an elastic layer provided with a polygonal convex portion having an apex angle on the upstream side in the toner conveying direction on the surface.

An example of the polygonal convex portion is shown in FIG. The convex portion only needs to have an apex angle in the toner conveyance direction, and may be any number of polygons. However, from the viewpoint of ease of toner flow, the convex portion is preferably axisymmetric in the toner conveyance direction, and has a rhombus shape. Preferably there is.
The convex portions may be arranged in a square arrangement or a staggered arrangement, but a staggered arrangement is preferable because it can reduce a blind spot area where toner particles stay.

FIG. 3 shows the relationship between the number of occurrences of toner fixation and filming and the number of images formed when the apex angle is very acute (groove in the toner conveyance direction). When the apex angle is very small, no toner stays on the surface of the developing roller, and no toner sticking occurs but filming occurs.
On the other hand, when the apex angle is very obtuse (groove perpendicular to the toner conveyance direction), as shown in FIG. 4, filming does not occur but toner fixation occurs.

The convex portion has an apex angle of 10 ° to 60 ° shown in FIG. If the angle is less than 10 °, scraping of the toner staying in the restricting portion is weak and toner sticking occurs, and if it exceeds 60 °, the ease of toner flow is reduced and filming occurs.
Here, the apex angle means an angle formed by intersecting two sides sandwiching the apex angle, and does not exclude a state where the apex of the apex is rounded due to wear or the like.

When the size of the convex portion is about the same as the particle size of the toner particles, the toner particle layer flowing in the concave portion formed between the convex portion and the convex portion becomes one or two layers, and the toner particle conveyance The toner is not retained due to the transmission of force, and the toner staying in the restricting portion can be scraped off. The lengths of the two sides forming the apex angle are 3 μm or more and 10 μm or less, respectively, and the height is preferably 3 μm or more and 10 μm or less, and more preferably 5 μm or more and 10 μm or less.
The area of the bottom surface of the convex portion is preferably 4 to 20 .mu.m ^2.

It is preferable to have 1000 or more and 10,000 or less convex portions per unit area (1 mm ² ). When the number is less than 1,000, the toner is not sufficiently scraped off, and the toner may be fixed. When the number is more than 10,000, the concave portion through which the toner flows is reduced, and filming may occur.

The toner carrier of the present invention has an elastic layer. By having the elastic layer, the stress applied to the toner is reduced.
The elastic layer is preferably formed of vulcanized rubber, and epichlorohydrin rubber selected from epichlorohydrin-ethylene oxide copolymer and epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer It is more preferable that it is formed by.
Conventionally used curable elastomers are easy to process, while low molecular weight components and unreacted components in rubber, such as silicone rubber, are likely to bleed, and it is necessary to form a bleed prevention layer. A material having high hardness gives a large stress to the toner. In addition, rubber rubber that is prone to wear, such as urethane rubber, is not durable enough, and requires two or more axes to rotate without contact development and DC + AC development bias with AC superimposed. However, it is necessary to use a complicated belt photoconductor, which is not suitable for downsizing and cost reduction.
Further, since the metal roller does not have elasticity, wear is accelerated under high stress, durability is not sufficient, and it is not suitable for compactness / cost reduction such as non-contact development and use of a belt photoreceptor.

The convex portion of the elastic layer can be formed by performing fine processing by a laser ablation method. The laser ablation method uses a phenomenon in which atoms, molecules, and clusters are evaporated from the surface when the solid is irradiated with a powerful laser beam, and the solid surface is scraped off. This is a method that enables extremely fine processing. In addition, according to the laser ablation method, filming can be prevented without causing cutting burrs or the like as toner fixing points.
In the present invention, it is preferable to reduce the shape of the photomask provided with the shape pattern by the mask projection method onto the object to be processed, project the laser light, and adjust the processing depth by the number of laser shots.
Since the reduction magnification in the mask projection method is determined by the ratio of the distance between the imaging lens and the object to be processed with respect to the distance between the mask and the imaging lens, increasing the reduction magnification increases the optical path length. If the distance between the imaging lens and the object to be processed is shortened (NA is increased) in order to suppress the optical path length, the depth of focus is shortened, so that the mask projection method is suitable for surface processing that does not penetrate.

  As the laser, an excimer laser using a rare gas of KrF can be preferably used. Since the laser has a wavelength of 248 nm and has the optimum energy for breaking the molecular chain, more precise processing is possible.

  The toner carrier of the present invention can be preferably used in a one-component developing method, and the shape may be either a roller shape or a belt shape, and is selected according to a copying apparatus, a facsimile machine, or a printer to be incorporated. Further, the toner carrier of the present invention may be incorporated in these apparatuses in the form of a process cartridge.

<Single component development device>
The one-component developing device of the present invention has at least a toner carrier, a toner supply member that supplies toner onto the toner carrier, and a toner replenishing unit, and averages the toner thin layer conveyed from the toner supply member. The restriction member is arranged.

FIG. 5 is a schematic diagram showing the configuration of the one-component developing device. In FIG. 5, there are a charging device (3) as a charging means, a developing device (5) as a developing means, and a toner on the photosensitive body (1) around the photosensitive body (1) along the surface movement direction. A transfer device (6) as a transfer means for transferring an image to a recording medium or an intermediate transfer member, and a cleaning device (7) for removing untransferred toner on the photosensitive member (1) are arranged in this order. Between the charging device (3) and the developing device (5), an exposure device (4) serving as an exposure unit that performs exposure based on image data on the surface of the charged photoreceptor (1) and writes an electrostatic latent image. Space is secured so that the light emitted from can pass to the photosensitive member 1. In FIG. 5, reference numeral (100) denotes a process cartridge described later.

The toner carrier (51) carries toner on its peripheral surface, rotates in contact with the photoreceptor (1), and supplies toner to the electrostatic latent image formed on the photoreceptor (1) for development. . The toner supply roller (52) is in contact with the peripheral surface of the toner carrier (51) and supplies toner onto the toner carrier (51). The toner supplied onto the toner carrier (51) is leveled and charged by the regulating member (54).
Further, the toner supply roller (52) is disposed below the toner carrier (51) at a shaft position, and further, a developer stirring member (stirring paddle) (53) for stirring the toner in the developing device, A toner replenishing member (screw) (not shown) is arranged further below.

<Process cartridge>
The process cartridge is an apparatus (part) that contains an image carrier (photoconductor) and further includes a means selected from a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit. If necessary, other means such as a static elimination means may be included. There are many shapes and the like of the process cartridge, but a general example is shown in FIG.
Here, the process cartridge includes a photosensitive member (101), and includes a charging unit (102), an exposure unit (103), a developing unit (104), and a cleaning unit (107). It has the means of. In the figure, (105) is a recording medium (transfer body), and (108) is a transfer means.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.

[Example 1]
Epichlorohydrin rubber (Hydrin T3106 manufactured by Nippon Zeon Co., Ltd.) was extruded on a 6 mm SUS metal shaft so that the rubber thickness would be 3 mm, and then stored in a 150 ° C. environment for 90 minutes for vulcanization. The surface was roughly polished with a polishing machine (LEO600-F4L-BME manufactured by Mizuguchi Seisakusho Co., Ltd.), and then finished with SZC manufactured by Mizuguchi Seisakusho Co., to obtain a rubber substrate for a developing roller.
Next, a photomask that holds 8000 rhombuses having an apex angle of 60 ° / side length of 25 μm per 1 mm ² is produced, and the substrate is irradiated with 10 shot lasers by an excimer laser processing apparatus, thereby forming a shape pattern on the photomask as rubber. Formed on a substrate. The reduction ratio in the laser processing at this time was 1/5.
Next, 0.03 parts by weight of Ketjen black (EC made by Ketjen Black) was added to 2.5 parts by weight of isocyanate (D170N made by Mitsui Chemicals Polyurethane Co., Ltd.) to 100 parts by weight of butyl acetate as a surface layer material. After stirring for 30 minutes using an Enterprises Co., Ltd., impregnation treatment was carried out, followed by baking at 150 ° C. for 2 hours to obtain a developing roller 1.

[Example 2]
A developing roller 2 was obtained in the same manner as in Example 1 except that the mask shape was changed to an apex angle of 30 °.

[Example 3]
A developing roller 3 was obtained in the same manner as in Example 1 except that the mask shape was changed to an apex angle of 10 °.

[Example 4]
A developing roller 4 was obtained in the same manner as in Example 2 except that the mask shape was changed to one having a side length of 15 μm.

[Example 5]
A developing roller 5 was obtained in the same manner as in Example 2 except that the mask shape was changed to one having a side length of 50 μm.

[Example 6]
A developing roller 6 was obtained in the same manner as in Example 1 except that the mask shape was changed to a triangle.

[Example 7]
A developing roller 7 was obtained in the same manner as in Example 6 except that the mask shape was changed to an apex angle of 30 °.

[Example 8]
A developing roller 8 was obtained in the same manner as in Example 6 except that the mask shape was changed to an apex angle of 10 °.

[Comparative Example 1]
A developing roller 9 was obtained in the same manner as in Example 1 except that the mask shape was changed to an apex angle of 90 °.

[Comparative Example 2]
A developing roller 10 was obtained in the same manner as in Example 1 except that the mask shape was changed to an apex angle of 5 °.

[Comparative Example 3]
A developing roller 11 was obtained in the same manner as in Example 2 except that the mask shape was changed to one having a side length of 1 μm.

[Comparative Example 4]
A developing roller 12 was obtained in the same manner as in Example 2 except that the mask shape was changed to one having a side length of 20 μm.

[Comparative Example 5]
The developing roller 13 was obtained in the same manner as in Example 2 except that the mask shape was changed to one having the number of convex portions of 500 / mm ² .

[Comparative Example 6]
A developing roller 14 was obtained in the same manner as in Example 2 except that the mask shape was changed to one having a number of convex portions of 15000 / mm ² .

[Comparative Example 7]
A developing roller 15 was obtained in the same manner as in Example 6 except that the mask shape was changed to an apex angle of 90 °.

[Comparative Example 8]
A developing roller 16 was obtained in the same manner as in Example 6 except that the mask shape was changed to an apex angle of 5 °.

[Comparative Example 9]
14.0 parts of polyol (Kuraray Co., F-510) and 17.5 parts of MDI (Sumitomo Bayer Urethane Co., Sumidur PF) were stirred for 5 minutes and heated to 115 ° C. The same shape pattern as Example 2 Cast into a cylindrical mold with an inner diameter of 12φ. In the mold, a SUS 6φ metal shaft is installed to be concentric.
After curing for 3 hours, the roller surface was roughly polished with a polishing machine (LEO600-F4L-BME manufactured by Mizuguchi Seisakusho), and then finished with SZC made by Mizuguchi Seisakusho to obtain a rubber substrate for a developing roller.
Next, 0.03 parts by weight of Ketjen black (EC made by Ketjen Black) was added to 2.5 parts by weight of isocyanate (Mitsui Chemicals Polyurethanes Co., Ltd., D170N) to 100 parts by weight of butyl acetate as a surface layer material. The developer roller 17 was obtained by stirring for 30 minutes using Marenterprises Co., Ltd., followed by impregnation and further baking at 150 ° C. for 2 hours.

[Comparative Example 10]
Epichlorohydrin rubber (Hydrin T3106 manufactured by Nippon Zeon Co., Ltd.) was extruded on a 6 mm SUS metal shaft so that the rubber thickness would be 3 mm, and then stored in a 150 ° C. environment for 90 minutes for vulcanization. The surface was roughly polished with a polishing machine (LEO600-F4L-BME manufactured by Mizuguchi Seisakusho Co., Ltd.), and then finished with SZC manufactured by Mizuguchi Seisakusho Co., to obtain a rubber substrate for a developing roller.
Next, 100 parts by weight of butyl acetate as a surface layer material, 2.5 parts by weight of isocyanate (D170N manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), 0.03 part by weight of Ketjen Black (EC manufactured by Ketjen Black Co., Ltd.), acrylic filler (Nippon Catalyst) 0.18 part by weight of MA1010 (manufactured by Kogyo Co., Ltd.) was added and stirred for 30 minutes with a turbula mixer (manufactured by Shinmaru Enterprises Co., Ltd.), then using a spray coating device (manufactured by Atmax Co., Ltd.), a rubber base for a developing roller The developing roller 18 was obtained by spraying on the surface to a film thickness of 10 μm and baking at 150 ° C. for 2 hours.

[Comparative Example 11]
The shape of Example 2 is imparted to a 12φ aluminum cylindrical surface by cutting, and the surface layer material similar to that of Example 1 is spray-applied to the surface, followed by baking at 150 ° C. for 2 hours to form the developing roller 19. Obtained.

The toner carrier produced above was evaluated by the following evaluation methods.
<Evaluation of toner adhesion>
Each roller was set on an IPSIO C310 manufactured by Ricoh, and solid images were continuously output in an environment of 27 ° C. and 80%. Halftone images were collected every 100 sheets to check for the presence of vertical white stripes.
A: The number of white lines generated is 8000 or more. B: 5000 to 8000. Δ: 2000 to 5000.times .: Less than 2000.

<Filming evaluation>
The developing roller was taken out every 100 sheets, air blown, and then the toner adhesion state on the developing roller was confirmed with a microscope.
A: No toner observed ○: Toner adhered but in powder state Δ: Toner adhered and melted with unknown powder shape X : Molten toner adhering to one side and the roller surface cannot be confirmed

<Bleed evaluation>
Roller was set on IPSIO C310 manufactured by Ricoh and stored for 1 week in 50 ° C 90% environment, then conditioned in MM environment (saturated humidity) for 1 hour, then halftone image was collected and the presence of horizontal black streaks was confirmed. .
◎: No streak at all ○: There is a streak but the density difference is 0.03 or less in ID ×: There is a streak and the density difference exceeds 0.03 in ID

<Abrasion evaluation>
Each roller was set on an IPSIO C310 manufactured by Ricoh, and a 1% yield image was output at 1 P / J in a 15% environment at 10 ° C., and a change in the roller surface roughness Ra was confirmed.
A: Change is less than 10% compared to the initial stage B: 10-30%
X: Over 30%

上記評価結果から、凸部の形状がトナー担持体回転方向上流側に１０°〜６０°の頂角を持つとトナー固着及びフィルミングを防止できることが分る。
この形状は規制ブレードに滞留しているトナーの動き出しのきっかけを与えつつ現像ローラ上のトナーが滞留することなく流れていくことにより固着/フィルミングの発生のしない形状となっている。６０°より大きいと現像ローラ上のトナー滞留が進みフィルミングが発生しやすくなり、１０°より小さいと固着が発生しやすくなってしまう。
また、凸部大きさはトナーの粒子径前後の大きさであることが好ましいことが分かる。

From the above evaluation results, it can be seen that toner sticking and filming can be prevented when the shape of the convex portion has an apex angle of 10 ° to 60 ° on the upstream side in the rotation direction of the toner carrier.
This shape is a shape that does not cause sticking / filming because the toner on the developing roller flows without stagnation while giving a start of movement of the toner staying on the regulating blade. If it is larger than 60 °, toner stays on the developing roller and filming is likely to occur, and if it is smaller than 10 °, sticking is likely to occur.
Further, it can be seen that the size of the convex portion is preferably about the particle diameter of the toner.

DESCRIPTION OF SYMBOLS 1 Photoconductor 3 Charging device 4 Exposure device 5 Developing device 6 Transfer device 7 Cleaning device 14 Roller 16 Roller 51 Toner carrier 52 Toner supply roller 53 Developer stirring member (stirring paddle)
54 regulating member 100 process cartridge 101 photoconductor 102 charging means 103 exposure means 104 developing means 105 recording medium (transfer body)
107 Cleaning means 108 Transfer means

JP 2005-212372 A JP 2007-127903 A Japanese Patent No. 4628932 JP 2009-3248 A

Claims (9)

A toner carrier for a one-component developing device having a toner carrier for conveying toner and a regulating member for regulating a toner conveyance amount on the surface of the toner carrier, the toner carrier having an elastic layer, The layer has polygonal convex portions having an apex angle on the upstream side in the toner conveying direction of 1000 to 10,000 per 1 mm ² , and the length of the side forming the apex angle is 3 μm to 10 μm. And the apex angle is 10 ° to 60 °. The toner carrier according to claim 1, wherein a height of the convex portion is 3 μm or more and 10 μm or less. The toner carrier according to claim 1, wherein the elastic layer is made of vulcanized rubber. The vulcanized rubber is an epichlorohydrin rubber selected from epichlorohydrin-ethylene oxide copolymer and epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer. The toner carrier described in 1. The toner carrying member according to claim 1, wherein the surface shape of the developing roller is formed by a laser ablation method. 6. The toner carrier according to claim 5, wherein the laser processing apparatus used for the laser ablation method is an excimer laser using a rare gas KrF. 7. A one-component developing device having a toner carrier for conveying toner and a regulating member for regulating the amount of toner on the surface of the toner carrier, wherein the toner carrier is the toner according to claim 1. A one-component developing device characterized by being a carrier. A process cartridge comprising the toner carrier according to claim 1. An image forming method using the toner carrier according to claim 1.

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