JP2012177853A - Developer carrier, developing device, process cartridge, image forming method, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer carrier that carries a non-magnetic one-component developer that prevents toner from being fused and fixed to a developer regulation member, and provides high-quality images without a decrease in density, white streaks, or black streaks for a long period.SOLUTION: A developer carrier 134 includes a core bar 134a, and an elastic layer 134b formed around the outer periphery of the core bar 134a. The periodic irregularity of the surface of the elastic layer is subjected to Fourier transform and represented by the power spectrum, and the result shows that the amplitude reaches the maximum value when the frequency f(1/mm) is 0<f<0.25.

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer carrier for forming an image such as a copying machine, a printer, and a fax machine. The present invention relates to an image forming apparatus.

In an image forming apparatus such as a copying machine, a facsimile machine, or a printer, an electrostatic latent image corresponding to image information is formed on an image carrier such as a photoconductor by optical writing or electrostatic recording, and the electrostatic latent image is formed. After the image is developed with the developer of the developing device to form a visible image, the visible image on the image carrier is transferred directly or via an intermediate transfer member to a recording material such as paper, The transferred image is fixed by a fixing device to form an image.
As a developer used in an image forming apparatus for developing an electrostatic latent image formed on an image carrier such as a photoreceptor and forming a visible image, a two-component developer composed of a toner and a carrier is used. And a one-component developer composed of toner alone.
Among them, the development method using a two-component developer can obtain a relatively stable and good recorded image, but is easy to cause deterioration of the carrier and a change in the mixing ratio of the toner and the carrier, and the apparatus is enlarged. There is a drawback of doing.
Therefore, a developing system using a one-component developer is used from the viewpoint of downsizing, cost reduction, and reliability of the apparatus.
In addition, when comparing a magnetic one-component developer and a non-magnetic one-component developer, in a developing method using a magnetic one-component developer, a magnetic material that is generally black magnetite powder is included in the toner that is the developer. For colors other than black, it is difficult to obtain a clear developer.
For this reason, when forming a multi-color image, a non-magnetic one-component toner which is a non-magnetic one-component developer is used.

On the other hand, the image forming apparatus using a non-magnetic one-component developer (hereinafter sometimes simply referred to as “toner”) is used in the actual market due to the trend of longer life, smaller size, and lower price. Each member of the image forming apparatus is required to supply a high-quality image stably over a long period of time with a simple structure as a whole system such as a developing device and a developer carrier, etc., with low cost and high durability.
A developing system for a one-component developer transports and supplies toner from a supply roller to a developer carrier, and passes the toner through a gap of a developer regulating member that is in contact with the developer carrier. A layer is formed, and development is performed by moving the toner from the developer carrying member onto the latent image of the photosensitive member by an electric field. Therefore, in order to supply a stable and high-quality image over time, it is important to form a thin toner layer on the developer carrier, and various technical means have been proposed and already known.

  However, as the toner thin layer is continuously formed, the toner stays in the developer regulating member and is fixed and fused, resulting in a decrease in density on the image and vertical stripes such as white stripes and black stripes. The image quality was degraded. Therefore, the developer is disposed by installing a roller for scraping the adhering toner on the developer regulating member or by applying an AC voltage to the developer regulating member and the developer carrying member to cause the toner to move between the two members. Technical means for suppressing adhesion and fusion of toner to the regulating member have been proposed. However, such a developing device has a complicated configuration and is expensive, and there is a problem that it is difficult to cope with the recent downsizing of the device.

  Therefore, in Patent Document 1, the toner moves between the two members by applying an AC voltage to the developing roller and the regulating blade for the purpose of preventing the deterioration of the image quality by suppressing the adhesion of the toner external additive to the regulating blade. Thus, a configuration is disclosed in which adhesion of external additives onto the regulating blade can be prevented. However, when an AC voltage is applied, it is assumed that the toner is negatively charged when the toner passes through the gap (regulator) between the regulating blade and the developing roller. Adhesion and sticking cannot be controlled. Furthermore, the power supply device for generating an alternating voltage is expensive and requires an installation space, and the problem of a low-priced, small-sized developing device and image forming device expected from the market has not been solved.

  Therefore, the present invention has been made in view of the above problems, and the problem is a non-magnetic one-component developer, in which the toner is fused and fixed to the developer regulating member, and the concentration is lowered over a long period. It is an object of the present invention to provide a developer carrier, a developing device, a process cartridge, an image forming method, and an image forming apparatus that can obtain a high-quality image free of white lines and black lines.

The features of the present invention, which is a means for solving the above problems, are listed below.
The developer carrying member of the present invention is a developer carrying member comprising a cored bar and an elastic layer formed on the outer periphery of the cored bar. As a result, the frequency f (1 / mm) has a maximum amplitude when 0 <f <0.25.
The developer carrier of the present invention is further characterized in that the maximum height difference of the irregularities on the surface of the elastic layer is in the range of 10 to 20 μm.
The developer carrying member of the present invention is further characterized in that the elastic layer is a low elastic rubber having a JIS-A hardness of 30 to 45 °.
The developer carrier of the present invention is further characterized in that the elastic layer further comprises a surface layer formed on the outer periphery.
The developer carrier of the present invention is further characterized in that the surface layer has organic spherical fine particles.
The developer carrier of the present invention is further characterized in that the spherical fine particles have a volume average particle size in the range of 10 to 20 μm.
The developer carrier of the present invention is further characterized in that the spherical particles are partially exposed from the surface layer.

The developing device of the present invention comprises a developer carrying member that carries a developer supplied to an image carrier on its surface and moves on the surface, a developer supply member that supplies the developer to the surface of the developer carrying member, In a developing device comprising a developer layer regulating member for thinning the developer carried on the surface of the developer carrying member and a developer containing device for containing the developer, the developer carrying member is any of the above A developer carrying member as described above.
The process cartridge of the present invention is a process cartridge in which a latent image carrier and a developing device that develops at least a latent image on the latent image carrier with a developer are integrated and detachable from the image forming apparatus. The developing device described above is used as the developing device.
The image forming apparatus of the present invention includes a latent image carrier that carries a latent image, a charging device that uniformly charges the surface of the latent image carrier, and the surface of the charged latent image carrier that is exposed based on image data. An exposure device for writing an electrostatic latent image, a developing device for supplying toner to the electrostatic latent image formed on the surface of the latent image carrier to visualize it, and a visible image on the surface of the latent image carrier. An image forming apparatus comprising: a transfer device that transfers to a transfer member; and a fixing device that fixes a visible image on the transfer member, wherein the developing device is the developing device described above. .
The image forming method of the present invention includes a charging step for uniformly charging the surface of the latent image carrier, an exposure step for exposing the surface of the charged latent image carrier based on image data, and writing an electrostatic latent image, A developer layer having a predetermined layer thickness is formed on the developer carrier by a developer layer regulating member, and the electrostatic latent image formed on the surface of the latent image carrier is developed through the developer layer to be visualized. In the image forming method, the developing step includes: a developing step for transferring; a transfer step for transferring the visible image on the surface of the latent image carrier to the transferred member; and a fixing step for fixing the visible image on the transferred member. The developing device described above is used.

The present invention, which is a means for solving the above problems, has the following specific effects.
By using the developer carrying body and developer apparatus of the present invention, the developer carrying body having a low roundness of the developer carrying body and an increased toner scraping ability is achieved, thereby achieving cost reduction and downsizing. In addition, adhesion and fusion of the toner to the developer regulating member can be suppressed.
Further, in the process cartridge, the image forming apparatus, and the image forming method of the present invention, the image density does not decrease over a long period of time, and a high-quality image free from vertical stripes such as white stripes and black stripes can be obtained.

1 is a schematic diagram illustrating a configuration of an embodiment of an image forming apparatus using a developing device of the present invention. It is the schematic which shows the structure of other embodiment of the image forming apparatus using the image development apparatus of this invention. It is a figure which shows the structure of the process cartridge to which the developing agent carrier of this invention is applied. It is a figure explaining the structure of one Embodiment of the image development apparatus of this invention. It is a figure which shows the structure of the developing agent carrier of this invention. FIG. 6 is a diagram illustrating a state of toner conveyed on a developer carrier. It is a figure which shows embodiment of the developer carrier of this invention. It is a figure which shows other embodiment of the developing agent carrier of this invention. It is a graph which shows the relationship between a frequency and an amplitude in the measurement of roundness.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

An embodiment of the present invention will be described.
The present invention relates to a developer carrier having a low cylindricity in order to improve the scraping ability of the toner in order to suppress the adhesion / fixation of the toner on the developer regulating member 136 with respect to the cross-sectional shape of the developer carrier 134. It has become a feature.
The features of the present invention will be described in detail with reference to the following drawings.
FIG. 1 is a schematic diagram showing the configuration of an embodiment of an image forming apparatus using the developing device of the present invention.
FIG. 2 is a schematic diagram showing the configuration of another embodiment of an image forming apparatus using the developing device of the present invention.
An image forming apparatus 1 according to an embodiment of the image forming apparatus of the present invention includes a document conveying device (ADF) 5 that conveys a document, a scanner unit 4 for reading a document, and a digital signal output from the scanner unit. In particular, the image forming unit 3 includes an image forming unit 3 that processes the image processing unit and forms an image on the recording member 6 based on a digital signal output from the image processing unit. In the scanner unit 4, an image of a document placed on the document placement table is read by a color CCD through an irradiation lamp, a mirror, and a lens, and the data is sent to the image processing unit. In the image processing unit, necessary processing is performed on the data, converted into an image signal, and sent to the image forming unit 3.

In the image forming unit 3, four yellow, cyan, magenta image forming units 10Y, 10C, 10M and four black image forming units 10K are arranged in parallel, and one intermediate for the four image forming units 10 is provided. A transfer belt 21 and one secondary transfer roller 23 are provided. As an example of the image forming unit 10 constituting the image forming apparatus 1, a configuration of a yellow image forming unit 10Y is shown.
Unless otherwise specified, the other cyan image forming unit 10C, magenta image forming unit 10M, and black image forming unit 10K have the same configuration and operation.
The image forming unit 10 can be used as a process cartridge 10 that can be attached to and detached from the main body of the image forming apparatus 1.
When the image forming operation is started, in the yellow image forming unit 10 </ b> Y, the surface of the photoreceptor 11, which is an electrostatic latent image carrier, is uniformly charged by the charging device 12. For charging, DC (direct current) or a bias in which AC (alternating current) is superimposed on DC is applied by a high-voltage power source.
Then, an electrostatic latent image of a yellow component image of a full-color original is formed on the charged photoreceptor 11 by exposure from an exposure device 30 for optical writing. This exposure process is performed by a laser beam scanner or LED using a laser diode.
The electrostatic latent image is visualized with yellow toner by the yellow developing device 13Y. Further, similar image forming operations are performed in the cyan image forming unit, the magenta image forming unit, and the black image forming unit 10 with a predetermined time difference, and toner images of cyan, magenta, and black colors are formed on the respective photoreceptors 11. Is done.

At this time, each developing device 13 uses toner which is a one-component developer. In particular, yellow, cyan, and magenta can be used as a non-magnetic one-component developer by using the following organic pigments. The black toner may be a magnetic one-component developer by using magnetite, but a non-magnetic one-component developer using carbon black is preferable from the viewpoint of fixability and high-quality image quality in color images.
Further, as resin components in the toner, polyester resin, styrene / chlorostyrene copolymer, styrene / propylene copolymer, styrene / butadiene copolymer, styrene / vinyl chloride copolymer, styrene / vinyl acetate copolymer, Styrene / maleic acid copolymer, styrene / acrylic acid ester copolymer, styrene / methacrylic acid ester copolymer, styrene / α-chloromethyl acrylate copolymer, styrene / acrylonitrile / acrylic acid ester copolymer, etc. Styrenic resin, vinyl chloride resin, styrene / vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyethylene resin, polypropylene resin, ionomer resin, these resins are not limited to single use, but two or more It can also be used together.
Examples of the colorant include carbon black, lamp black, iron black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6C rake, calco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane. Any conventionally known dyes and pigments such as dyes such as dyes can be used alone or in combination, and can be used as a black toner or a full color toner. The amount of these colorants to be used is usually 1 to 30% by weight, preferably 3 to 20% by weight, based on the toner resin component.

A charge control agent may be used as necessary. As the charge control agent, any conventionally known charge control agent such as a nigrosine dye, a metal complex dye, or a quaternary ammonium salt can be used. The amount of these charge control agents used is 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on the toner resin component.
As the external additive, any conventionally known external additive such as silica, titanium oxide, silicon carbide, aluminum oxide, barium titanate or the like can be used alone or in combination. The amount of these external additives used is 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight, based on the toner weight. By using these external additives, the rising of the charge of the toner becomes much better than when it is not mixed, and the fluidity is further improved, leading to an improvement in image quality.
In addition, toner production methods can be broadly classified into pulverization methods and polymerization methods. In the pulverization method, raw materials such as binder resin, colorant, and wax are mixed, and a kneaded product in which colorant, wax, etc. are dispersed in the resin by applying a shearing force while applying heat is rolled and cooled to form a plate. After pulverization, the particles are classified so as to have a desired particle size distribution, and finally an external additive is mixed to produce a toner.
In addition, there are a suspension polymerization method, an emulsion polymerization method, a polymer suspension method and the like in which an oil phase is emulsified, suspended or aggregated in an aqueous medium to form toner base particles.
The developing device 13 will be described later.

In order to superimpose the toner images Y, C, M, and K formed on the photosensitive member 11 in each of the image forming units 10Y, 10C, 10M, and 10K as one full-color image on the intermediate transfer belt 21, this intermediate transfer is performed. On the back side of the belt 21, a transfer roller 14 is disposed at a position opposite to the photoconductor 11 of each image forming unit 10, and a predetermined transfer bias is applied to the transfer roller 14, whereby the toner image of each image forming unit 10 is transferred. The images are successively transferred onto the intermediate transfer belt 21 in a superimposed manner.
The surface of the photoreceptor 11 in each image forming unit 10 after being transferred to the intermediate transfer belt 21 is neutralized by a light neutralization unit (not shown).
After that, when the machine is operating, the photosensitive member 11 of each image forming unit 10 is brought into a contact state before the rotation, and when the machine is stopped, the photosensitive member 11 is separated from the photosensitive member 11. After the toner image is transferred to the intermediate transfer belt 21, the surface of the photoreceptor is neutralized by the light neutralizing unit, and the cleaning device 15 first (upstream position in the rotational direction of the photosensitive body in the cleaning unit) first counters the rotational direction of the photosensitive body. A blade made of a rubber-like elastic body is brought into contact with the photoconductor 11 in the direction to remove toner and deposits. The toner removed by the cleaning device 15 is transported to a waste toner storage tank through a waste toner transport path. There is also a cleanerless system in which the developing device 13 collects the transfer residual toner without providing the cleaning device 15 on the photoconductor 11, and various known cleaning devices can be employed in the present invention.
The charging device 12 is a contact charging method in which a charging member disposed opposite to the photoconductor 11 is brought into contact and a predetermined DC voltage (DC) is applied to uniformly charge the surface of the photoconductor 11. A roller is used. A non-contact type potential sensor is installed at a position opposite to the photoreceptor surface between the exposure position and the development position on the photoreceptor surface in the rotation direction of the photoreceptor, and a charging bias is set so that a predetermined charging potential and a latent image potential are obtained. Adjust the value and exposure.

Deposits such as toner and paper dust remaining on the surface of the intermediate transfer belt 21 after the transfer of the full-color toner image to the recording member 6 are removed by a cleaning brush roller and a cleaning blade (not shown) of the intermediate transfer belt cleaning device 22. In the same manner as the photoconductor waste toner, the toner is conveyed to a waste toner storage unit. The intermediate transfer belt 21, a roller 211 facing the transfer roller 14, a transfer bias power source, a belt driving shaft, and the like, tension rollers 211, 212, and 213 installed in the transfer device 20 are included in the intermediate transfer belt by a cam mechanism (not shown). The intermediate transfer belt 21 can be changed between a state in contact with the photoconductor 11 of each image forming unit 10 and a state in which the intermediate transfer belt 21 is separated by applying or releasing tension to the belt 21.
The transfer roller 14 forms a transfer electric field by applying a predetermined transfer bias +400 to +2500 V supplied from an unillustrated high-voltage power supply for each color, and transfers the toner image on the photoconductor 11 to the intermediate transfer belt 24 or A full color image is formed by sequentially transferring to the recording member 6 which is a transfer material.

Thereafter, the toner image transferred to the intermediate transfer belt 21 is synchronized with the secondary transfer roller 23 to which a predetermined bias is applied to the toner image on the intermediate transfer belt 21 that has become one full-color image. Then, it is transferred onto the recording member 6 conveyed. The transfer device 20 includes a primary transfer roller 14, a secondary transfer roller 23, an intermediate transfer belt 21, a belt cleaning device 22, and the like.
In addition, the recording member 6 is selected from the plurality of paper feed cassettes 40 arranged in the paper feed device 2 by the pickup roller 42 and the recording member 6 selected by the control of the image forming apparatus 1 is set to 1 from the paper feed cassette 40. It is pulled out one by one. Then, the image is conveyed to the image forming unit 3 by the conveyance roller 43. Then, the timing with the toner image on the intermediate transfer belt 21 is measured by the registration roller 44 and sent to the secondary transfer roller 23.
Thereafter, the recording member 6 to which the toner image has been transferred is conveyed to the fixing device 31 and heated and pressurized to fix the toner image on the recording member 6 and output a full color image.

In the image forming apparatus 1 shown in FIG. 2, unlike the image forming apparatus 1 shown in FIG. 1, no intermediate transfer belt is disposed. The toner images of the respective colors formed by the four yellow, cyan, magenta, and black image forming units 10Y, 10C, 10M, and 10K are directly transferred onto the recording member 6 while the recording medium is directly conveyed by the conveying belt. Thereafter, as in the image forming apparatus 1 shown in FIG. 1, the recording member 6 is conveyed to the fixing device 31 and heated and pressurized to fix the toner image on the recording member 6 and output a full color image.
The toner mark sensor (TM sensor) 25 measures the toner image density and each color position on the conveyor belt 24 by using a regular reflection type or diffusion type sensor, and adjusts the image density and color matching.
FIG. 3 is a diagram showing the configuration of a process cartridge to which the developer carrying member of the present invention is applied.
In FIG. 3, one process cartridge 2 is formed. However, the process cartridge 10 is any one of the photoconductor 11, the charging device 12, the developing device 13, the cleaning device 15, and the lubricant applying device. It is only necessary to integrally support the above and be detachable from the image forming apparatus 1, and is not limited to the process cartridge 2 of the present embodiment.

FIG. 4 is a diagram illustrating the configuration of an embodiment of the developing device of the present invention.
The developing device 13 stores a non-one-component developer (hereinafter, simply referred to as “toner”) and stores the toner supply chamber 131, and the toner in the toner supply chamber 131 does not aggregate below the toner supply chamber 131. A toner agitating member 135 for agitating the toner to be prepared, a developer carrier 134 rotatably disposed at a position in contact with or close to the photosensitive member 11, and a developer carrier 134 rotatably disposed in contact with the developer carrier 134. A toner supply / recovery member 137 that supplies toner to the developer carrier 134 and collects toner remaining on the developer carrier 134 after development, and the toner in the moving direction of the surface of the developer carrier 134 It is disposed at a position downstream of the supply / recovery member 137 and upstream of a position in contact with or close to the photoconductor 11 to regulate the amount of toner on the developer carrier 134 and at the same time, a friction band. Composed of the developer regulating member 136. to.
The developer carrier 134 is applied with a predetermined developing bias from a high voltage power source (not shown). By applying this developing bias, a potential difference is provided between the photosensitive member 11 and the developer carrier 134, and an electric field can be formed to develop the toner.
The toner supply / recovery member 137 has a structure in which a conductive shaft is covered with a foam material having a structure having pores (cells) on the surface thereof, and the toner in the developing device 13 is efficiently attached and taken in, and also developed. Toner deterioration due to pressure concentration at the contact portion with the agent carrier 134 is prevented. The foamed material is set to have an electric resistance of about 10 ³ to 10 ¹⁴ Ω when a bias of about DC (direct current) 100 [V] is applied between the conductive shaft and the surface of the foamed material.
A supply bias having a value that is offset in the same direction as the charging polarity of the toner with respect to the developing bias applied to the developer carrier 134 is applied to the toner supply / recovery member 137. This supply bias acts in the direction in which the precharged toner is pressed against the developer carrier 134 at the contact portion with the developer carrier 134. The toner supply / recovery member 137 rotates in the clockwise direction as viewed in FIG. 4 and collects the toner adhering to the developer carrier 134 while removing the toner adhering to the surface and nearby toner on the developer carrier 134. The coating is supplied to the surface.

The developer regulating member 136 is made of a metal leaf spring material such as SUS304CSP or SUS301CSP stainless steel or phosphor bronze with a JIS symbol, and a linear pressure of 10 to 100 [N / m] on the surface of the developer carrier 134 at the free end side. The toner that has passed under the linear pressure is thinned, and charges are applied mainly by frictional charging. Further, in some cases, the developer regulating member 136 is applied with a regulating bias having a value offset in the same direction as the toner charging polarity with respect to the developing bias. However, the offset direction is not limited to this, and the offset may be 0 or the offset direction may be changed.
Further, the developer regulating member 136 has a bent portion that is bent at a leading end thereof in a straight line toward an obliquely upward direction. The bending angle of the bent portion with respect to the developer regulating member 136 is 90 degrees or more. Here, the bent portion of the developer regulating member 136 is in contact with the peripheral surface of the developer carrier 134. The toner stirring member 135 is provided below the extension line of the bent portion of the developer regulating member 136. More specifically, the peripheral line at the tip of the toner stirring member 135 is located below the extension line. By arranging the toner stirring member 74 in this way, the toner on the developer carrier 134 that cannot pass through the developer regulating member 136 can be conveyed onto the toner supply member 137. As shown in FIG. 4, if the toner stirring member 74 exists on the extension line of the developer regulating member 136, the flow of the toner scraped off by the developer regulating member 136 is inhibited, and the toner stays. May not be sufficiently prevented.
The shortest distance between the peripheral line at the tip of the toner stirring member 135 and the extension line is set to 5 mm or less. The reason why the shortest distance is 5 mm or less is that if it exceeds 5 mm, the conveying force by the toner stirring member 135 is difficult to be transmitted.
Further, a toner seal member (not shown) is brought into contact with the developer carrier 134 at a portion where the toner remaining on the developer carrier 134 without being developed on the photosensitive member 11 returns to the developing device 13 again. It is provided and sealed so that the toner does not leak out of the developing device 13. The toner seal member contacts the toner on the developer carrying member 134 to remove the toner.

Further, the photosensitive member 11 is rotated in the counterclockwise direction. Therefore, the surface of the developer carrying member 134 moves in the same direction as the traveling direction of the photosensitive member 11 at a position facing the photosensitive member 11.
The developer carrying member 134 is thinned by the developer regulating member 136, conveyed to a position facing the photosensitive member 11 by the rotation of the developer carrying member 134, and applied to the developer carrying member 134. In accordance with the latent image electric field formed by the electrostatic latent image on the photoconductor 11, it moves to the surface of the photoconductor 11 and is developed.

The developer carrier 134 rotates in the clockwise direction, and conveys the toner held on the surface to a position where the developer regulating member 136 and the photoconductor 11 are opposed to each other.
FIG. 5 is a diagram showing the configuration of the developer carrying member of the present invention.
As shown in FIG. 5, the developer carrier 134 is composed of a core metal 134a and an elastic layer 134b. The elastic layer 134b has a roller shape in which a cored bar shaft is covered with an elastic layer made of an elastomer such as rubber. The elastic layer formed on the outer periphery of the core bar is made of a material whose surface is easily charged to a polarity opposite to that of the toner. The elastic layer 134b is formed of a low elastic rubber having a hardness of 30 to 45 ° or less according to JIS-A in order to keep the contact state with the photoreceptor 11 uniform. Further, the volume resistance is set to an electric resistance value of 10 ³ to 10 ¹¹ Ω · cm in order to cause the developing bias to act.

FIG. 6 is a diagram for explaining the state of toner conveyed on the developer carrying member.
As shown in (a), when the developer carrier 134 having a high roundness is used, the amount of toner passing between the developer carrying member 136 and the developer regulating member 136 is small, so that it adheres to the developer regulating member 136. The toner adheres on the developer regulating member 136 without being scraped off, and is gradually fixed by heat and / or pressure due to the collision of the toner. Further, since there is little change in the amount of toner passing therethrough, it is difficult to generate an impact that scrapes off the toner once fixed.
On the other hand, as shown in (b), when the developer carrier 134 having a low roundness is used, the amount of toner passing between the developer carrying member 136 and the developer regulating member 136 varies greatly. Even if the toner adhering to the member 136 is generated, the amount of toner passing therethrough is greatly changed, so that an impact such as scraping off the toner once fixed can be generated and scraped off.

Therefore, if the roundness is too low, the distance between the developer carrying member 134 and the developer regulating member 136 is not constant, so that the amount of toner passing therethrough becomes non-uniform, and the toner image formed is particularly solid. In some images, the image density may become uneven.
For this purpose, as the roundness representing periodic unevenness, the surface of the developer carrier 134 is subjected to FFT (Fast Fourier Transform) processing as a signal, and the FFT processing result is calculated. As is well known, the Fourier transform is a series of calculations that extract the frequency contained in a signal using Fourier integration. If there is a periodic fluctuation in speed, the frequency is the inverse of that period. On the other hand, the fluctuation of the unevenness can be expressed by the amplitude on the vertical axis. Whereas the Fourier transform assumes a signal that is infinitely continuous, the variation in unevenness in the rotational direction is finite, so a discrete Fourier transform that discretely processes the signal is used. Thus, FFT refers to an algorithm with a reduced amount of calculation in the discrete Fourier transform.
Therefore, the amplitude and phase with respect to the frequency, which is the displacement of the rotation having a frequency corresponding to the periodic unevenness in the rotation direction of the developer carrier 134, is extracted, and the rotation of the developer carrier 134 is based on this amplitude and phase. Regulates unevenness of direction.

The developer carrier 134 of the present invention has a maximum amplitude at a frequency f (1 / mm) of 0.08 ≦ f ≦ 0.23.
The fact that the frequency f (1 / mm) here has a maximum value of 0.08 ≦ f ≦ 0.23 indicates that the actual developer carrier 134 has a maximum of 4.3-12. It shows that it has a waviness of 5 mm period. Thus, in the toner having a volume average particle size in the range of 6 to 10 μm, the developer carrying member 134 in which large irregularities appear in the maximum range of 4.3 to 12.5 mm, the toner adhering to the developer regulating member 136 is removed. Even if it occurs, since the change in the amount of toner passing therethrough is large, an impact that scrapes the toner once fixed can be generated and scraped off.
As a result, in the case of the developer carrier 134 having a high roundness, that is, a cross section close to a perfect circle, the amount of toner entering the restricting portion is almost constant with no change in time, and therefore toner vibration is small. Therefore, as the formation of the toner thin layer proceeds, the toner is likely to be caught on the developer regulating member 136 at a certain point, and the toner is likely to stay from the starting point to cause adhesion or sticking. On the other hand, in the case of the developer carrier 134 having a low roundness, for example, an elliptical cross section, the amount of toner entering the restricting portion varies depending on the point on the roller. As a result, toner retention can be suppressed and induction of adhesion and fixation can be reduced.
In the case of the developer carrier 134, the members necessary for the development system are only a general component such as a supply roller, the developer carrier 134, the developer regulating member 136, and the photosensitive member 11. Space saving is possible without the need for a special device. Further, in order to reduce the roundness of the developer carrier 134, it is only necessary to omit the roller polishing step, so that the cost can be reduced.
Further, the developer carrying member 134 of the present invention has a maximum height difference of surface irregularities in the range of 10 to 20 μm. If the maximum height difference of the unevenness of the surface of the developer carrier 134 exceeds 20 μm, the difference in the amount of toner transported depending on the location of the surface of the developer carrier becomes too large, resulting in uneven density in the formed image. End up. On the other hand, if it is less than 10 μm, the difference in the toner transport amount is small, it is difficult for impact to occur, and it becomes difficult to obtain the effect of scraping off the toner once fixed.

Further, as described above, in the developer carrier 134 of the present invention, the elastic layer 134b has a low hardness of 30 to 45 ° or less in JIS-A in order to keep the contact state with the photoreceptor 11 uniform. It is made of elastic rubber. As a result, in the case of rubber having a high hardness exceeding JIS-A hardness of 45 °, stress is applied to the members such as the photosensitive member 11 and the developer regulating member 136 that are in contact with the toner and the developer carrier 134. Conversely, in the case of a rubber having a low hardness of JIS-A hardness of less than 30 °, it is easy to be deformed, the difference in the amount of toner transport is small, the impact is hard to occur, and the effect of scraping the toner once fixed is obtained. Becomes difficult.
Low elasticity rubbers include epichlorohydrin rubber, urethane rubber, silicone rubber, EPDM, natural rubber, butyl rubber, nitrile rubber, NBR, polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, chloroprene rubber, acrylic A cross-linking agent and a vulcanizing agent can be added in order to use one type selected from rubber and the like, and a mixture of two or more types thereof, and further cross-link the rubber-like substance. In any case of organic peroxide crosslinking and sulfur crosslinking, a vulcanization aid, a vulcanization accelerator, a vulcanization retarder, and the like can be used. In addition to the above, foaming agents, plasticizers, softeners, tackifiers, tackifiers, separating agents, mold release agents, extenders, colorants, etc., which are commonly used as rubber compounding agents, have characteristics. It can add in the range which does not impair.
In the case of having a hard film according to the present invention, the elastic body needs to follow the hard film, and therefore needs a certain degree of hardness. Among the above-mentioned elastic bodies, EPDM, NBR, epichlorohydrin rubber, etc. are particularly good. . In addition to hardness, electrical characteristics, particularly electrical resistance, are important. In the case of an elastic body, various conductivity-imparting agents can be added to adjust the resistance. As conductive materials, powders include conductive carbon such as ketjen black EC and acetylene black, rubber carbon such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT, and oxidation treatment. Color carbon, pyrolytic carbon, indium-doped tin oxide (ITO), tin oxide, titanium oxide, zinc oxide, copper, silver, germanium, and other metals, and metal oxides, polyaniline, polypyrrole, polyacetylene, and other conductive polymers And so on.

  Further, a surface layer 134b2 is provided on the surface of the elastic layer 134b. The surface layer 134b2 can be obtained by performing various coatings such as a dip method, spray coating, and roll coating. As the surface layer, charge control particles such as acrylic fine particles and nigrosine charge control material can be dispersed in the surface layer, or a surface film can be formed with a thermosetting resin such as an amino resin. It is effective that a nitrogen-containing resin is present in the surface layer because of its ability and stability. In particular, as a nitrogen-containing resin, a surface layer formed by a curing reaction between a curing precursor having a reactive group (hydroxy group, carboxyl group, silanol group, methylol group, etc.) that reacts with an amino group and a polyamine crosslinking agent. It is particularly preferred. In this case, as the polyamine crosslinking agent, a polyamine having a triazine (1-3-5 triazine) structure, for example, a melamine or a guanamine compound can be preferably used. It is preferable to use a resin such as polyurethane or polysilicon. As a result, the chargeability of the toner can be negative, and furthermore, it has thermal stability, exhibits extremely excellent flexibility and electrical insulation, and is resistant to mechanical stress (wear, impact, etc.). be able to.

Further, the surface layer 134b2 may contain organic spherical fine particles. The presence of spherical fine particles on the surface of the surface layer can be expected to improve the scraping performance of the toner. The organic spherical fine particles may be any resin and are not limited. As the resin that forms the spherical fine particles, any resin can be used as long as it can form a dispersion in an aqueous medium. And a dispersion of fine spherical resin particles is preferable. The spherical fine particles may be a thermoplastic resin or a thermosetting resin. For example, a vinyl resin, a polyurethane resin, an epoxy resin, a polyester resin, a polyamide resin, a polyimide resin, a silicon resin, a phenol resin, Examples include melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin. These resins may be used in combination of two or more. Of these, vinyl resins, polyurethane resins, epoxy resins, and polyester resins are preferable from the viewpoint that a dispersion of fine spherical resin particles is easily obtained.
Furthermore, the volume average particle diameter of the spherical fine particles is in the range of 10 to 20 μm. By making the surface irregularity of the elastic layer 134b the same, if the volume average particle diameter of the spherical fine particles exceeds 20 μm, the difference in the amount of toner transported depending on the location of the developer carrier surface becomes too large, and the formed image As a result, shading unevenness occurs. On the other hand, if it is less than 10 μm, the difference in the toner transport amount is small, it is difficult for impact to occur, and it becomes difficult to obtain the effect of scraping off the toner once fixed. However, it is preferable that the particle size distribution is narrow, and the ratio of the volume average particle size to the number average particle size is preferably in the range of 1.01-1.50. Thus, by dispersing in the medium at the time of manufacture, the particle size distribution becomes sharp and the dispersion is stable. Examples of the method for measuring the particle size distribution include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter).
Furthermore, spherical particles are partially exposed from the surface layer 134b2. By projecting from the surface layer 134b2, the toner transportability is stabilized, and the amount of toner passing therethrough is greatly changed. Therefore, an impact that scrapes the toner once fixed can be generated and scraped off.

(Examples 1 to 4)
FIG. 7 is a view showing an embodiment of the developer carrying member of the present invention.
Example 1
As shown in FIG. 7A, the elastic layer is formed by epichlorohydrin rubber Hydrin T3106 manufactured by Nippon Zeon Co., Ltd. with a thickness of 3 mm on the outer periphery of the metal surface of a metal shaft having a diameter of 6 mm. Thereafter, polishing was performed with LEO-600-F4L-BME manufactured by Mizuguchi Seisakusho and polishing liquid SZC. In addition, 3 parts by weight of hexamethylene diisocyanate D170N manufactured by Mitsui Chemicals, 2.5 parts by weight of polyurethane polyol A2789 manufactured by the same company, 4.8 parts by weight of carbon black manufactured by Fuji Dye Co., Ltd., 2.5 parts by weight of methyl ethyl ketone, acetic acid The mixture was dissolved in a mixed solvent of 6 parts by weight of butyl and 54 parts by weight of ethyl acetate, and 0.21 part by weight of Neostan U-820 manufactured by Nitto Kasei Co., Ltd. was added to the catalyst to prepare a coating solution. A coating film was produced from above the base layer by spray coating, and annealed at 150 ° C. for 1 hour to thermally cure the coating film.
(Example 2)
As shown in FIG. 7B, the elastic layer uses the developer carrying member mounted on the IPSIO SP C310 on the surface of a metal shaft having a diameter of 6 mm as it is. This developer carrier was polished with LEO-600-F4L-BME manufactured by Mizuguchi Seisakusho and polishing liquid SZC as a polishing apparatus. In addition, 3 parts by weight of hexamethylene diisocyanate D170N manufactured by Mitsui Chemicals, 2.5 parts by weight of polyurethane polyol A2789 manufactured by the same company, 4.8 parts by weight of carbon black manufactured by Fuji Dye Co., Ltd., 2.5 parts by weight of methyl ethyl ketone, acetic acid The mixture was dissolved in a mixed solvent of 6 parts by weight of butyl and 54 parts by weight of ethyl acetate, and 0.21 part by weight of Neostan U-820 manufactured by Nitto Kasei Co., Ltd. was added to the catalyst to prepare a coating solution. A coating film was produced from above the base layer by spray coating, and annealed at 150 ° C. for 1 hour to thermally cure the coating film.

FIG. 8 is a view showing another embodiment of the developer carrying member of the present invention.
(Example 3)
As shown in FIG. 8 (a), the elastic layer is formed by epichlorohydrin rubber Hydrin T3106 manufactured by Nippon Zeon Co., Ltd. with a wall thickness of 3 mm on the outer periphery of the gold surface of a metal shaft having a diameter of 6 mm. Thereafter, polishing was performed with LEO-600-F4L-BME manufactured by Mizuguchi Seisakusho and polishing liquid SZC. In addition, 3 parts by weight of hexamethylene diisocyanate D170N manufactured by Mitsui Chemicals, 2.5 parts by weight of polyurethane polyol A2789 manufactured by the same company, 4.8 parts by weight of carbon black manufactured by Fuji Dye Co., Ltd., 2.5 parts by weight of methyl ethyl ketone, acetic acid It is dissolved in a mixed solvent of 6 parts by weight of butyl and 54 parts by weight of ethyl acetate, 0.27 parts by weight of highly crosslinked PMMA spherical fine particles (20 mm) manufactured by Sekisui Plastics Kogyo Co., Ltd. is added, and Neostan U- manufactured by Nitto Kasei Co., Ltd. is added to the catalyst. The coating liquid was adjusted by adding 0.21 part by weight of 820. A coating film was produced from above the base layer by spray coating, and annealed at 150 ° C. for 1 hour to thermally cure the coating film.
Example 4
As shown in FIG. 8B, the elastic layer uses the developer carrying member mounted on the IPSIO SP C310 on the surface of a metal shaft having a diameter of 6 mm. This developer carrier was polished with LEO-600-F4L-BME manufactured by Mizuguchi Seisakusho and polishing liquid SZC as a polishing apparatus. In addition, 3 parts by weight of hexamethylene diisocyanate D170N manufactured by Mitsui Chemicals, 2.5 parts by weight of polyurethane polyol A2789 manufactured by the same company, 4.8 parts by weight of carbon black manufactured by Fuji Dye Co., Ltd., 2.5 parts by weight of methyl ethyl ketone, acetic acid It is dissolved in a mixed solvent of 6 parts by weight of butyl and 54 parts by weight of ethyl acetate, 0.27 parts by weight of highly crosslinked PMMA spherical fine particles (20 mm) manufactured by Sekisui Plastics Kogyo Co., Ltd. is added, and Neostan U- manufactured by Nitto Kasei Co., Ltd. is added to the catalyst. The coating liquid was adjusted by adding 0.21 part by weight of 820. A coating film was produced from above the base layer by spray coating, and annealed at 150 ° C. for 1 hour to thermally cure the coating film.

(Comparative Example 1)
The developer carrier used in the IPSIO SP C220 was used as it was. (Comparative Example 2)
The developer carrier used in the CLP660DN manufactured by SAMSUNG was used as it was.
(Comparative Example 3)
The elastic layer is formed by forming an epichlorohydrin rubber epichromer made by Daiso Co., Ltd. with a thickness of 3 mm on the outer periphery on the surface of a metal shaft having a diameter of 6 mm. Thereafter, polishing was performed with LEO-600-F4L-BME manufactured by Mizuguchi Seisakusho and polishing liquid SZC. In addition, 3 parts by weight of hexamethylene diisocyanate D170N manufactured by Mitsui Chemicals, 2.5 parts by weight of polyurethane polyol A2789 manufactured by the same company, 4.8 parts by weight of carbon black manufactured by Fuji Dye Co., Ltd., 2.5 parts by weight of methyl ethyl ketone, acetic acid It is dissolved in a mixed solvent of 6 parts by weight of butyl and 54 parts by weight of ethyl acetate, 0.27 parts by weight of highly crosslinked PMMA spherical fine particles (20 mm) manufactured by Sekisui Plastics Kogyo Co., Ltd. is added, and Neostan U- manufactured by Nitto Kasei Co., Ltd. is added to the catalyst. The coating liquid was adjusted by adding 0.21 part by weight of 820. A coating film was produced from above the base layer by spray coating, and annealed at 150 ° C. for 1 hour to thermally cure the coating film.

The roundness of the developer carrier 134 of Examples 1 to 4 and Comparative Examples 1 to 3 was measured using a high precision roundness / cylindrical shape measuring device round test RAH-5100A manufactured by Mitutoyo Corporation. .
FIG. 9 is a graph showing the relationship between frequency and amplitude in the measurement of roundness.
As shown in FIG. 9, a power spectrum was prepared by measuring the roundness, and the value of the maximum amplitude frequency (1 / mm) was read therefrom.
At the same time, the maximum height difference, which is the difference between the highest point and the lowest point, was measured in the roughness curve obtained by the roundness measurement.

<Experiment method>
Images were evaluated in Examples 1 to 4 and Comparative Examples 1 to 3, and image evaluation was performed.
The developing device and the image forming apparatus were modified from Ricoh's IPSiO SP C310.
As the toner, a toner having a negative polarity was used.
Evaluation was performed by the following white stripes and transportability.
<White stripe>
The degree of white streaks entering the image when the durability of 5000 sheets was performed with the 5% chart 3P / J was evaluated.
○: 0 △: 1-9 ×: 10 or more <Conveyance>
The change in M / A of the toner on the developer carrying member under actual machine durability under the same conditions as the white stripe was evaluated.
○: Less than 15% Δ: 15 to less than 30% ×: 30% or more

表１から明らかなように、実施例１ないし４はいずれも、白スジ、搬送性が○であったが、比較例１ないし３はいずれも、白スジ、搬送性が×ないし△であり、実用上問題のある範囲であった。

As is apparent from Table 1, all of Examples 1 to 4 were white streaks and transportability was ◯, but Comparative Examples 1 to 3 were all white streaks and transportability was X to Δ. It was a practically problematic range.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper feeder 3 Image forming part 4 Scanner part 5 Automatic document feeder (ADF)
6 Toner 10 Image forming unit (process cartridge)
DESCRIPTION OF SYMBOLS 11 Photoconductor 12 Charging device 13 Developing device 131 Toner supply chamber 134 Developer carrier 134a Core metal 134b Elastic layer 134b2 Surface layer 134c Spherical fine particle 135 Toner stirring member 136 Developer regulating member 137 Supply member 14 Transfer roller 15 Cleaning device 20 Transfer device 21 Intermediate transfer belt 211, 212, 213 Support roller 22 Belt cleaning device 23 Secondary transfer roller 24 Transport belt 25 TM sensor 30 Exposure device 31 Fixing device 40 Paper feed cassette 42 Pickup roller 43 Transport roller 44 Registration roller 47 Discharge roller 48 Discharge Paper tray

JP2007-232990

Claims (11)

With a mandrel,
In the developer carrying member provided with an elastic layer formed on the outer periphery of the cored bar,
As a result of Fourier transform of the periodic unevenness on the surface of the elastic layer and expressing it as a power spectrum, the frequency f (1 / mm) has a maximum amplitude of 0.08 ≦ f ≦ 0.23. Agent carrier. 2. The developer carrying member according to claim 1, wherein the maximum height difference of the irregularities on the surface of the elastic layer is in the range of 10 to 20 μm. The developer carrying member according to claim 1, wherein the elastic layer is a low elastic rubber having a JIS-A hardness of 30 to 45 °. The developer carrying member according to claim 1, wherein the elastic layer includes a surface layer formed on an outer periphery. The developer carrying member according to claim 4, wherein the surface layer has organic spherical fine particles. The developer-carrying member according to claim 5, wherein the spherical fine particles have a volume average particle diameter in the range of 10 to 20 μm. The developer carrier according to claim 5 or 6, wherein the spherical particles are partly exposed from the surface layer. A developer carrier that carries the developer supplied to the image carrier on the surface and moves the surface;
A developer supply member for supplying the developer to the surface of the developer carrying member;
A developer layer regulating member for thinning the developer carried on the surface of the developer carrying body;
In a developing device including a developer container for storing a developer,
The developing device according to claim 1, wherein the developer carrying member is the developer carrying member according to claim 1. In the process cartridge in which the latent image carrier and the developing device that develops at least the latent image on the latent image carrier with a developer are integrated and detachable from the image forming apparatus,
A process cartridge using the developing device according to claim 8 as the developing device. A latent image carrier for carrying a latent image;
A charging device that uniformly charges the surface of the latent image carrier;
An exposure device that exposes the surface of the charged latent image carrier based on image data and writes an electrostatic latent image;
A developing device for supplying toner to the electrostatic latent image formed on the surface of the latent image carrier to visualize it;
A transfer device for transferring the visible image on the surface of the latent image carrier to the transfer target;
An image forming apparatus comprising: a fixing device that fixes a visible image on a transfer target;
An image forming apparatus, wherein the developing device is the developing device according to claim 8. A charging step for uniformly charging the surface of the latent image carrier;
An exposure process for exposing the surface of the charged latent image carrier based on the image data and writing an electrostatic latent image;
A developer layer having a predetermined layer thickness is formed on the developer carrier by a developer layer regulating member, and the electrostatic latent image formed on the surface of the latent image carrier is developed through the developer layer to be visualized. A development process to
In an image forming method comprising: a transfer step of transferring a visible image on the surface of a latent image carrier to a transfer target; and a fixing step of fixing the visible image on the transfer target;
An image forming method using the developing device according to claim 8 in the developing step.

Images