JP2004271554A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the remaining amount sensing accuracy of a toner remaining amount sensing device in a developing device. <P>SOLUTION: Styrene resin is used as the principal material of transparent members 48a, 48b which block up sensing windows 48c, 48d disposed in side walls of a toner storage chamber 43 holding a powdery polymerized toner 42 manufactured by a polymerization method and based on styrene resin for transmitting toner remaining amount sensing light in the toner storage chamber, whereby tight adhesion of the polymerized toner by electrostatic force is suppressed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００４７】
表１は、ポリカーボネート樹脂製の透明部材４８ａ，４８ｂと、この実施の形態におけるスチレン樹脂製の透明部材４８ａ，４８ｂを使用し、トナー収容室４３に重合トナー４２を充填した現像装置４におけるトナー残量検出の成功回数を調査した結果を示している。この調査結果によれば、ポリカーボネート樹脂製の透明部材４８ａ，４８ｂを使用した現像装置４では、試行回数１０回中６回のトナー残量検出不良があるが、この実施のけいたいのようにスチレン樹脂製の透明部材４８ａ，４８ｂを使用した現像装置４では、試行回数１０回中のトナー残量検出不良は解消している。
【００４８】
【発明の効果】
本発明は、現像容器内を横切るようにトナー残量検出光線を透過させる検出窓を塞ぐ透明部材を粉末トナーの摩擦帯電特性と同様な摩擦帯電特性の材質としたことにより、透明部材に付着する粉末トナーの量を軽減して検出精度の高い光学式のトナー残量検出装置を構成することができる。
【００４９】
また、前記透明部材の材質を前記粉末トナーの主原料（スチレン樹脂）と同種類の材質（スチレン樹脂）とすることにより、前記透明部材を容易に実現することができる。
【００５０】
また、前記透明部材をレンズの形態に形成してトナー漏れとトナー残量検出光線の整形に兼用することにより、透明部材の構成を簡素化することができる。
【図面の簡単な説明】
【図１】本発明になる現像装置を備えた電子写真装置の縦断側面図である。
【図２】本発明になる現像装置の縦断側面図である。
【図３】図２に示した現像装置を設置した部分の平面図である。
【符号の説明】
１…感光ベルト、４（４Ｙ，４Ｍ，４Ｃ，４Ｋ）…現像装置、４２…重合法トナー、４３…トナー収容室、４４…現像ローラ、４５ａ，４５ｂ，４５ｃ…トナー搬送羽根、４８…トナー残量検出装置、４８ａ，４８ｂ…透明部材、４８ｃ，４８ｄ…検出窓、４８ｅ…ＬＥＤ、４８ｆ…フォトセンサ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a developing device, and more particularly, to a developing device using powder toner.
[0002]
[Prior art]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 1-309080 [Patent Document 2]
JP-A-55-89869 [Patent Document 3]
Japanese Patent Application Laid-Open No. H11-133739 [Patent Document 4]
Many of the powder toners used in a developing device in an electrophotographic apparatus such as an electrophotographic printer and an electrophotographic copying machine are manufactured by a so-called pulverizing method. However, the powder toner produced by the pulverization method is approaching its limit in providing functions such as finer particle size, low-temperature fixability, and durability in high-speed printing, so that the particle size can be freely controlled. Powder toners produced by a polymerization method capable of satisfying both durability and low-temperature fixability have been spotlighted.
[0003]
In general, a developing device rotatably supports a developer carrying member (developing roller) in a developing container, and a toner layer thickness regulating member attached to the developing container is opposed to the surface of the developer carrying member. It is configured such that a thin layer of the powder toner is formed on the developer carrying member by a layer thickness regulating member.
[0004]
Note that the toner layer thickness regulating member is configured by attaching a friction regulating material such as a rubber plate to the tip of a plate-like rubber holding plate, and is provided so that the friction regulating material comes into contact with the developer carrying member.
[0005]
JP-A-1-309080 (Patent Document 1) describes a configuration in which a developer carrier is rotatably supported on a housing by a support shaft, and a toner layer thickness regulating member is positioned based on the support shaft. I have. Japanese Patent Application Laid-Open No. 55-89869 (Patent Document 2) provides means for connecting and supporting a developer carrying member and a toner layer thickness regulating means to regulate their linear expansion coefficients and improve positioning accuracy. Is described. Further, Japanese Patent Application Laid-Open No. H11-133739 (Patent Document 3) describes a configuration of a structure for preventing leakage of toner in a developing device.
[0006]
Such a developing device includes a toner remaining amount detecting device because when the development of the electrostatic latent image is performed, the powder toner is consumed and the remaining amount is reduced, and when the remaining amount is too small, the developing capability is reduced. . Japanese Patent Application Laid-Open No. 2001-100507 (Patent Document 4) discloses a detection device for a remaining amount of toner in a developing device, which is provided in the developing container so as to be able to transmit a light beam for detecting the amount of remaining toner so as to cross the inside of the developing container. And a transparent member that closes the detection window, and the toner remaining amount detection light emitted from the light emission source on one outside of the developing container is made to enter the detection window, pass through the inside of the developing container, and is emitted to the outside of the other, This is an optical configuration that receives the light with a photodetector. In a state where the light beam for detecting the remaining amount of toner cannot be received by the photodetector, a sufficient amount of powder toner remains in the developing container and the light beam for detecting the remaining toner amount is generated. The configuration is such that it is determined that the light is blocked, and when the amount of received light increases, it is determined that the remaining amount of the powder toner has decreased so that the toner remaining amount detection light beam cannot be sufficiently blocked.
[0007]
[Problems to be solved by the invention]
In such a developing device, various measures are taken for the purpose of accurately positioning the developer carrying member and the toner layer thickness regulating member to uniformly form a thin layer of the powdered toner, and to reduce toner leakage from the developing container. However, in recent years, further uniformity of image quality has been demanded for high image quality and high definition.
[0008]
In order to meet such requirements, the performance of the developer carrying member and the toner layer thickness regulating member must be improved, and the toner leakage must be further improved.
[0009]
In addition, it is necessary to provide accurate information on the remaining amount of the powder toner in the developing device in consideration of maintainability.
[0010]
An optical toner remaining amount detecting device that detects the remaining amount of the powder toner in the developing device is a developing device that uses a high-charged powder toner such as a powder toner manufactured by a polymerization method. In some cases, the powder toner is strongly electrostatically adhered to the inner surface of the transparent member that blocks the detection window that transmits the amount detection light beam, and it may be difficult to accurately detect the remaining amount of toner.
[0011]
An object of the present invention is to provide a developing device that can constitute an optical toner remaining amount detecting device with high detection accuracy.
[0012]
More specifically, the inner surface of a transparent member that closes a detection window for transmitting a light beam for detecting the amount of toner remaining in a developing container that holds powder toner used for development by being attached to a developer carrier (developing roller). It is an object of the present invention to provide a developing device capable of reducing a decrease in detection accuracy due to electrostatic adhesion of powder toner and hindering transmission of a toner remaining amount detection light beam.
[0013]
Another object of the present invention is to easily realize the transparent member capable of reducing the electrostatic adhesion of the powder toner.
[0014]
Still another object of the present invention is to simplify the configuration of the transparent member capable of reducing the electrostatic adhesion of the powder toner.
[0015]
[Means for Solving the Problems]
The present invention provides a developing container containing a powder toner, and a rotatable, powder toner in the developing container attached to the surface of the developing container to form a thin layer of the powder toner, and the formed powder toner. A developer carrying member that transports the thin layer to a position facing the latent image holding member on which the electrostatic latent image is formed and develops the electrostatic latent image to make it a visible image; In a developing device provided with a detection window provided in the developing container so as to be able to transmit a toner remaining amount detection light beam and a transparent member closing the detection window, the transparent member closing the detection window has the same frictional charging characteristics as the powder toner. By using a material having a triboelectric charging characteristic, it is possible to prevent the powder toner from firmly adhering to the transparent member due to electrostatic force.
[0016]
More specifically, the material of the transparent member closing the detection window is made of the same kind of material as the main raw material of the powder toner.
[0017]
Further, the powder toner is manufactured by a polymerization method using a styrene resin as a main raw material, and a material of the transparent member is a styrene resin.
[0018]
Further, the transparent member for closing the detection window is formed in the form of a lens.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 is a longitudinal sectional side view of an electrophotographic apparatus provided with a developing device according to the present invention.
[0021]
In the electrophotographic apparatus according to the present embodiment, a photoconductor (photosensitive belt) 1 as a latent image holding member is a member having a photoconductive photosensitive layer formed on a surface thereof, and has a predetermined constant value by supporting rollers 1a to 1c. It is supported so as to rotate at a speed, and the surface is exposed to corona discharge of the charging device 2 while rotating in the direction of the arrow 1d to uniformly charge.
[0022]
The exposure device 3 exposes the surface of the photosensitive belt 1 that is uniformly charged and rotates to form an electrostatic latent image corresponding to a predetermined color (yellow Y, magenta M, cyan C, black K). The exposure device 3 scans and exposes the surface of the photosensitive belt 1 with a light beam 3a, and blinks the light beam 3a dot by dot in accordance with an image or character information generated by a personal computer, an image scanner, or the like. An electrostatic latent image is formed thereon.
[0023]
The developing device 4 (4Y, 4M, 4C, 4K) stores powder toner of a predetermined color manufactured by a polymerization method, and selectively brings a color corresponding to an electrostatic latent image close to the photosensitive belt 1. Then, the electrostatic latent image on the photosensitive belt 1 is developed into a visible image (toner image).
[0024]
The intermediate transfer belt 5, which is an intermediate transfer member, is supported by the rotating drum 5a and the support roller 5b so as to rotate in the direction of arrow 5c while contacting the surface of the photosensitive belt 1 on which the toner image is formed and rotating. The photosensitive belt 1 is installed such that a toner image formed on the photosensitive belt 1 is transferred at a contact position with the belt 1. The intermediate transfer belt 5 is a member for forming a color toner image by repeatedly transferring a toner image formed on the photosensitive belt 1 and superimposing toner images of respective colors.
[0025]
The paper feed cassette 6 contains recording paper 6 a which is a recording medium such as plain paper or OHP paper, and has a timing such that the completed color toner image on the intermediate transfer belt 5 is aligned with the timing of moving to the position of the transfer roller 7. Sends out the recording paper 6a (in the direction of arrow 6b).
[0026]
The transfer roller 7 contacts the intermediate transfer belt 5 with the recording paper 6 a sent from the paper feed cassette 6 to apply a mechanical transfer pressure and also applies an electrostatic transfer force to the intermediate transfer belt 5 so that the recording paper 6 a It functions to transfer the color toner image to the recording paper 6a.
[0027]
The fixing device 8 includes a heating roller 8a and a pressure belt 8c wound around a pressure roller 8b, and heats and melts the color toner image by passing the recording paper 6a onto which the color toner image has been transferred, thereby forming the recording paper 6a. And is discharged onto the discharge tray 9.
[0028]
Here, a polymerization toner which is a powder toner manufactured by a polymerization method will be described. As a method for producing the polymerization toner, there are a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, an interfacial polymerization method and the like, and any production method may be employed.
[0029]
The polymerization method toner is a first step in which a monomer mixture is added to a dispersion in which wax fine particles are present to perform seed emulsion polymerization, and the polymer dispersion and the colorant dispersion obtained in the first step are mixed, A second step of preparing aggregated particles by aggregating and heating the particles of the dispersion, and a third step of washing and drying the aggregated particles obtained in the second step and externally adding the fine particles. Manufactured.
[0030]
The production of a toner by a conventional pulverization method includes six steps including a resin polymerization step, a raw material mixing step, a melt kneading step, a pulverization step, a classification step, and an external addition step.
[0031]
Therefore, in the production of the polymerization method toner, the number of steps can be significantly reduced, and in particular, since the melt-kneading step and the pulverizing step which consume a large amount of production energy can be reduced, the production energy and the production cost can be significantly reduced. It can be carried out.
[0032]
In addition, by performing emulsion polymerization using a low-melting wax and in the presence of the wax particles, it is possible to manufacture a toner having both low-temperature fixability and durability. As this wax, any one of known waxes having a low melting point can be used. Specific examples of such a wax include olefin-based waxes such as low molecular weight polyethylene, low molecular weight polypropylene, copolymerized polyethylene, grafted polyethylene, and grafted polypropylene, behenyl behenate, montanic acid ester, and stearyl stearate. Ester wax having a chain aliphatic group, hydrogenated castor oil, vegetable wax such as carnauba wax, ketone having a long chain alkyl group such as distearyl ketone, silicone wax having an alkyl group and a phenyl group, stearic acid and the like Higher fatty acids, higher fatty acid amides such as oleic acid amide and stearic acid amide, long-chain fatty acid alcohols, long-chain fatty acid polyhydric alcohols such as pentaerythritol, and their partial esters, paraffin wax, Fischer-Tropschwa Have nests, etc..
[0033]
Among these waxes, more preferred are waxes having a melting point of 100 ° C. or lower, more preferably waxes having a melting point in the range of 40 to 90 ° C., and particularly preferably 50 to 80 ° C. Range. When the melting point exceeds 100 ° C., the effect of lowering the fixing temperature becomes poor.
[0034]
Next, the four developing devices 4 (4Y to 4K) will be described with reference to FIGS. The developing devices 4 (4Y to 4K) in this embodiment are configured as replacement parts. The four developing devices 4Y to 4K differ from each other only in the color of the toner to be used, and have the same other configuration.
[0035]
FIG. 2 is a vertical sectional side view of the developing device 4, and FIG. 3 is a plan view of a portion where the developing device 4 is installed.
[0036]
The developing container 41 includes a toner accommodating chamber 43 for accommodating a polymerization toner 42 that is a powder toner used for development, and a developing roller 44 that is a developer carrying member is provided at an opening at a front end of the toner accommodating chamber 43. The toner accommodating chamber 43 includes toner conveying blades 45 a to 45 c and a supply roller 46, and conveys the polymerization toner 42 toward the developing roller 44 by rotation of the toner conveying blades 45 a to 45 c and the supply roller 46. The supply roller 46 is a roller made of a conductive elastic foam material, and supplies the polymerization toner 42 transported to the front part of the toner storage chamber 43 by the toner transport blades 45 a to 45 c so as to touch the surface of the developing roller 44. I do.
[0037]
The developing roller 44 is driven by a driving unit (not shown) and rotates in the direction of an arrow 44a. A toner layer thickness regulating blade 47 is provided to face the surface of the developing roller 44. The polymerization toner 42 supplied so as to be in contact with the developing roller 44 is regulated to a thin layer having a thickness suitable for development by a toner layer thickness regulating blade 47 and adheres to the developing roller 44. The electrostatic latent image on the photosensitive belt 1 is developed by being conveyed so as to be close to the photosensitive belt 1 by being frictionally charged by being rubbed by the regulating blade 47.
[0038]
In such a developing device 4, since the polymerization toner 42 is consumed by developing the electrostatic latent image, the remaining amount of toner in the toner storage chamber 43 is reduced.
[0039]
The toner remaining amount detecting device 48 in this embodiment is provided on both side walls of the developing container 41 and closed by transparent members 48a and 48b to prevent toner leakage. Is transmitted through the toner chamber 43 toward the photo sensor 48f, which is the lower limit of the remaining amount of the polymerization toner 42 in the toner chamber 43. And the inner surfaces of the transparent members 48a and 48b are rubbed and cleaned by a PET resin cleaner 48g attached to the toner conveying blade 45c.
[0040]
The transparent members 48a and 48b are formed in the form of a lens that converges light emitted from the LED 48e into parallel light, transmits the light inside the toner storage chamber 43, and narrows the light to a state suitable for being incident on the photosensor 48f. , 48d. As described above, the transparent members 48a and 48b are formed in the form of lenses to prevent leakage of toner from the toner storage chamber 43 and to condense and narrow down the detection light beam, thereby simplifying the configuration of the toner remaining amount detecting device 48. it can. However, an LED (light emitting source) 48e having a function of emitting parallel rays suitable for detecting the remaining amount of toner and a photosensor (photodetector) 48f having a function of narrowing down and detecting the parallel rays are used. In the configuration, the transparent members 48a and 48b may be in the form of a flat plate.
[0041]
In the developing device 4 configured as described above, when the remaining amount of the polymerization method toner 42 in the toner storage chamber 43 is sufficiently large, the toner storage chamber 48 passes through the transparent member 48a of the detection window 48c from the LED 48e of the remaining toner detection device 48. The light beam for detecting the remaining amount of toner that has entered the inside 43 is blocked by the polymerization toner 42 and does not reach the photosensor 48f (the photosensor 48f does not receive light). Therefore, when the detection signal of the photosensor 48f is at the non-light receiving level, it can be determined that the remaining amount of the polymerization toner 42 in the toner storage chamber 43 is sufficient. However, when the remaining amount of the polymerized toner 42 in the toner storage chamber 43 decreases to near the lower limit, a part of the light beam for detecting the remaining amount of toner that has entered the toner storage chamber 43 from the LED 48e through the transparent member 48a of the detection window 48c is formed by the polymerization method. The light reaches the photo sensor 48f without being blocked by the toner 42 (the photo sensor 48f receives light). Therefore, the detection signal of the photosensor 48f when the remaining amount of the polymerization method toner 42 in the toner storage chamber 43 reaches the lower limit state is set in advance as a toner remaining amount lower limit detection reference value. By performing a control process of comparing the detection signal with the toner remaining amount lower limit detection reference value each time printing is performed, the remaining amount (toner shortage) of the polymerization toner 42 in the toner storage chamber 42 can be monitored.
[0042]
While the developing device 4 is operating, the inner surfaces of the transparent members 48a and 48b are rubbed and cleaned by a cleaner 48g provided on the rotating toner conveying blade 45c. It is possible to reduce the detection error due to the polymerization method toner 42 attached to 48b.
[0043]
Incidentally, in the developing device 4 using a toner charged to a high potential such as the polymerization toner 42, the toner is firmly fixed to the inner surfaces of the transparent members 48a and 48b closing the detection windows 48c and 48d by electrostatic force. Since the transparency of the transparent members 48a and 48b is reduced to prevent transmission of the remaining toner detection light beam, the detection accuracy of the remaining toner may be reduced.
[0044]
Therefore, in this embodiment, the polymerization toner 42 manufactured using a styrene resin as a main raw material is used, and the transparent members 48a and 48b that cover the detection windows 48c and 48d are formed of the styrene resin. The cleaning rate by the cleaner 48g is improved by weakening the electrostatic adhesion of the polymerized toner 42 to the transparent members 48a and 48b so that the frictional charge difference between the toner 42 and the transparent members 48a and 48b is hardly generated.
[0045]
With this configuration, the amount of the polymerization toner 42 adhering to the inner surfaces of the transparent members 48a and 48b closing the detection windows 48c and 48d of the developing container 41 is reduced, and the accuracy of optical toner remaining amount detection is improved. Can be done. Moreover, by making the main material of the polymerization toner 42 and the material (type) of the transparent members 48a and 48b the same, it is possible to easily reduce the frictional charge difference.
[0046]
[Table 1]

[0047]
Table 1 shows that the toner remaining in the developing device 4 using the transparent members 48a and 48b made of polycarbonate resin and the transparent members 48a and 48b made of styrene resin in this embodiment and filling the toner accommodating chamber 43 with the polymerized toner 42 is used. The result of having investigated the frequency | count of success of quantity detection is shown. According to the result of the investigation, in the developing device 4 using the transparent members 48a and 48b made of polycarbonate resin, there are six times out of ten attempts to detect the remaining amount of toner. However, as shown in FIG. In the developing device 4 using the transparent members 48a and 48b made of resin, the defective detection of the remaining amount of toner during ten trials is eliminated.
[0048]
【The invention's effect】
According to the present invention, the transparent member that closes the detection window that transmits the toner remaining amount detection light so as to traverse the inside of the developing container is made of a material having the same triboelectric charging characteristic as the triboelectric charging characteristic of the powder toner, so that the toner adheres to the transparent member. An optical toner remaining amount detecting device with high detection accuracy by reducing the amount of powder toner can be configured.
[0049]
Further, the transparent member can be easily realized by using a material (styrene resin) of the same type as the main material (styrene resin) of the powder toner.
[0050]
Further, by forming the transparent member in the form of a lens so as to be used for shaping the toner leakage and the toner remaining amount detection light beam, the configuration of the transparent member can be simplified.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional side view of an electrophotographic apparatus provided with a developing device according to the present invention.
FIG. 2 is a longitudinal sectional side view of the developing device according to the present invention.
FIG. 3 is a plan view of a portion where the developing device shown in FIG. 2 is installed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Photosensitive belt, 4 (4Y, 4M, 4C, 4K) ... Developing device, 42 ... Polymerized toner, 43 ... Toner storage chamber, 44 ... Developing roller, 45a, 45b, 45c ... Toner conveyance blade, 48 ... Toner residual Amount detection devices, 48a, 48b: transparent members, 48c, 48d: detection windows, 48e: LEDs, 48f: photo sensors.

Claims (4)

A developing container for accommodating the powdered toner, rotatably provided, and adhering the powdered toner in the developing container to the surface thereof to form a thin layer of the powdered toner and statically forming the formed thin layer of the powdered toner; A developer carrying member which is conveyed to a position facing the latent image holding member on which the electrostatic latent image is formed to develop the electrostatic latent image into a visible image; and a toner residual amount which crosses the inside of the developing container. In a developing device having a detection window provided in the developing container so as to be capable of transmitting a detection light beam and a transparent member closing the detection window,
A developing device, wherein the transparent member closing the detection window is made of a material having a triboelectric charging characteristic similar to that of the powder toner. 2. The developing device according to claim 1, wherein a material of the transparent member closing the detection window is made of the same material as a main raw material of the powdered toner. 3. The developing device according to claim 1, wherein the powder toner is manufactured by a polymerization method using a styrene resin as a main raw material, and a material of the transparent member is a styrene resin. The developing device according to claim 1, wherein the transparent member that closes the detection window is formed in the form of a lens.

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