JP2004130597A - Image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate image formation failures because of abrasion of a contact type write head and an image carrier, contact instabilities by friction, and image formation failures because of a leak between write heads. <P>SOLUTION: The image formation device is equipped with a writing means 3 for writing an electrostatic latent image on the image carrier 2 by contacting or approaching a surface of the image carrier and impressing a write voltage, a developing means 4 for forming a developer image by supplying a developer 6 and developing the electrostatic latent image formed on the image carrier by the writing means 3, a transfer means 5 for transferring the developer image formed on the image carrier by the developing means 4 to a transfer body, and a means for supplying a dielectric liquid 7 to the surface of the image carrier 2. The electrostatic latent image is written by the writing means 3 in a state while the dielectric liquid 7 is applied to the surface of the image carrier 2. A friction force between the contact type write head (electrode) and the image carrier is reduced, so that the abrasion of the write head and the image carrier is prevented. A life time can be made long by the reduction of an abrasion amount. <P>COPYRIGHT: (C)2004,JPO

Description

【００３７】
【表２】

実験では、〔表１〕の実験パラメータの計３２４水準（＝６×２×９×３）で行い、〔表２〕の実験結果では、これらの３２４水準の実験のうち、１つでも良かった場合に○とした。この結果によっても、粘度９０（ｍＰａ・ｓ）以下では、書込ヘッドが振動してトナー像形成不良が起こり、また、粘度１０１００（ｍＰａ・ｓ）以上では、書込ヘッドがドラムに引っ張られるため、トナー像形成不良が起こるが、粘度１００〜１００００（ｍＰａ・ｓ）においては、書込ヘッドの振動、書込ヘッドがドラムに引っ張られるのを抑える効果が現れ、トナー像形成不良が起こらなくなる効果の顕著であることが明らかになっている。
【００３８】
【発明の効果】
以上の説明から明らかなように、本発明によれば、像担持体に静電潜像を形成し現像して現像剤像を形成し転写体に転写する画像形成装置において、像担持体の表面に接触又は近接して書込電圧を印加し像担持体上に静電潜像を書き込む書込手段と、現像剤を供給して書込手段により像担持体上に形成された静電潜像を現像し現像剤像を形成する現像手段と、現像手段により像担持体に形成された現像剤像を転写体に転写する転写手段と、像担持体の表面に誘電性液体を供給する手段とを備え、像担持体の表面に誘電性液体が塗布された状態で書込手段により静電潜像を書き込むようにしたので、接触式の書込ヘッド（電極）と像担持体の摩擦力を低減し、書込ヘッド及び像担持体の磨耗を防止し、磨耗量の減少による長寿命化を実現できる。
【００３９】
書込手段は、像担持体上に複数の凸部を有する書込電極を並列に配置したものであることを特徴とし、像担持体の表面に塗布される誘電性液体は、凸部より厚い塗布膜を形成することを特徴とし、誘電性液体を供給する手段は、像担持体上の転写手段から現像手段までの間に配置されることを特徴とするので、書込ヘッドと像担持体の摩擦力を低減し、書込ヘッド及び像担持体の磨耗を防止すると共に書込ヘッド間でのリーク防止による良好な画像形成が可能になる。
【００４０】
像担持体上に電荷を一様にする除電部を備えることを特徴とし、誘電性液体を供給する手段は、像担持体上の電荷を一様にする除電部を兼ね備えることを特徴とし、除電部は、導電性部材で構成され且つ電圧を供給されることを特徴とするので、トナー像保持性能を向上し、装置の小型化を図ることができる。
【００４１】
誘電性液体を供給する手段は、誘電性液体を含む現像剤であり、該現像剤を現像手段から像担持体上に供給することにより塗布膜を形成することを特徴とし、誘電性液体は、粘度１００〜１００００（ｍＰａ・ｓ）の範囲のものであることを特徴とし、像担持体は、表面に島状に導電性微粒子が分散形成されているので、書込ヘッドと像担持体の摩擦力を低減し、書込ヘッド及び像担持体の磨耗を防止すると共に、磨耗量の減少による長寿命化を実現でき、トナー像保持性能を向上し、装置の小型化を図ることができ、書込ヘッド間でのリーク防止による良好な画像形成が可能になる。
【図面の簡単な説明】
【図１】本発明に係る画像形成装置の実施の形態を示す図である。
【図２】像担持体を独立フローティング電極構造とした本発明に係る画像形成装置の他の実施の形態を示す図である。
【図３】像担持体を誘電体層と抵抗層の二層構造とした本発明に係る画像形成装置の他の実施の形態を示す図である。
【図４】像担持体を独立電極単層構造とした本発明に係る画像形成装置の他の実施の形態を示す図である。
【図５】画像形成部の外観斜視図である。
【図６】誘電性液体の外部塗布機構を有する本発明に係る画像形成装置の他の実施の形態を示す図である。
【図７】除電機構を兼ねた誘電性液体の外部塗布機構を有する本発明に係る画像形成装置の他の実施の形態を示す図である。
【図８】除電機構を別配置した外部塗布機構を有する本発明に係る画像形成装置の他の実施の形態を示す図である。
【図９】帯電書込と液体現像を採用した本発明に係る画像形成装置のタンデム方式に採用した他の実施の形態を示す図である。
【図１０】帯電書込装置の基材を像担持体に弾性接触させ、基材に設けた書込電極により像担持体上に静電潜像を形成する画像形成装置の概略を説明するための図である。
【符号の説明】
１…画像形成装置、２…像担持体、３…書込ヘッド、４…現像装置、４ａ…現像剤担持体、４ｂ…供給部材、５…転写部、６…現像剤、７…誘電性液体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus that forms an electrostatic latent image on an image carrier by a writing electrode, develops the image, forms a developer image, and transfers the image to a transfer member.
[0002]
[Prior art]
There is a multi-needle electrode method for selectively forming an electrostatic latent image on an image carrier using a charged writing head. However, in this method, the potential of the electrostatic latent image is easily varied, and the electrostatic latent image resolution is high. Also changes over time, so that the image quality deteriorates, and furthermore, a gap between the needle electrode and the image carrier and a high-precision holding member and positioning member for positioning are required, which leads to an increase in complexity and size of the apparatus. In addition, the contact pressure is high due to the needle electrode, and the electrode and the image carrier are damaged in a short time. It is difficult to increase the printing speed, and the device is enlarged as it is used as an intermediate image carrier. Have.
[0003]
In order to solve this problem, there has been proposed an image forming apparatus in which a base material of a charged writing device is elastically contacted with an image carrier, and an electrostatic latent image is formed on the image carrier by a writing electrode provided on the base material. (For example, refer to Patent Documents 1 and 2), and the outline of the image forming apparatus will be described with reference to FIG.
[0004]
In FIG. 10, an image forming apparatus 21 includes a latent image carrier 22 on which an electrostatic latent image is formed, and a writing device that contacts the latent image carrier 22 and writes an electrostatic latent image on the latent image carrier 22. A developing device 24 for developing the electrostatic latent image on the latent image carrier 22 with the developer carried and conveyed by a developer carrier (developing roller) 24a; A transfer device 26 for transferring the toner image (developer image) on the latent image carrier 22 developed by the developing device 24 to a transfer material 25 such as paper; and a charge remaining on the latent image carrier 22 after the transfer. And a latent image carrier uniform charge control device 27 for charging the latent image carrier 22 or transferring the latent image carrier 22 to a uniform charge state on the latent image carrier 22.
[0005]
The writing head 23 has a high insulating property such as FPC (abbreviation of Flexible Print Circuit, hereinafter referred to as FPC) or PET (abbreviation of polyethylene terephthalate, hereinafter referred to as PET), and is a relatively soft and elastic flexible base. The material 23a and the writing electrode 23b which is supported by the base material 23a and which is lightly pressed onto the latent image carrier 22 with a weak elastic restoring force due to the bending of the base material 23a to come into contact therewith and write the electrostatic latent image. Have.
[0006]
In the image forming apparatus 21 configured as described above, the latent image carrier uniform charge control device 27 puts the latent image carrier 22 into a uniform charge state, and then contacts the latent image carrier 22. The electrostatic latent image is written on the latent image carrier 22 in a uniformly charged state by the mounting head 23. Then, the electrostatic latent image on the latent image carrier 22 is developed with the developer of the developing device 24, and the toner image is transferred to the transfer material 25 by the transfer device 26.
[0007]
[Patent Document 1]
JP-A-2002-178554
[Patent Document 2]
JP-A-2002-172813
[Problems to be solved by the invention]
In the above-described conventional image forming apparatus, the writing head and the image carrier are in contact with each other and are arranged in contact with a certain degree of contact pressure. Therefore, the writing head or the image carrier is abraded by wear. When the write head is scraped off due to wear and the convex portion (contact portion) disappears, the latent image cannot be formed. When the shape of the convex portion (contact portion) is deformed, the shape of the latent image is also deformed and formed. Will be done. Also, if the image carrier is scraped off by abrasion, the charge injection portion for injecting the charge also wears out, making it impossible to form a latent image. Therefore, in the charging writing process, it is necessary to minimize wear of the constituent members (writing head, image carrier) and the like.
[0010]
Further, since a high voltage is applied to the write head, image formation failure due to air discharge (crosstalk, leak) between adjacent write heads becomes a problem. Therefore, it is necessary to arrange the write heads at a certain distance or more. At present, the pitch between write heads is set to 70 to 100 μm. If they are adjacent to each other, the influence of aerial discharge is large, and the process is not established. Further, the conventional image forming apparatus has a problem in that, in the charging writing process, residual toner or the like after transfer adheres to the write head unit, resulting in poor image formation.
[0011]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention solves the above problems, and eliminates image formation failure due to wear of a contact-type writing head and an image carrier, contact instability due to friction, and image formation failure due to leakage between the writing heads. Is what you do.
[0012]
Therefore, the present invention provides an image forming apparatus which forms an electrostatic latent image on an image carrier, develops the same, forms a developer image, and transfers the developer image to a transfer body. Writing means for applying a voltage to write an electrostatic latent image on the image carrier; supplying developer and developing the electrostatic latent image formed on the image carrier by the writing means; Developing means for forming an image, transfer means for transferring a developer image formed on the image carrier by the developing means to a transfer body, and means for supplying a dielectric liquid to the surface of the image carrier The electrostatic latent image is written by the writing means in a state where the dielectric liquid is applied to the surface of the image carrier.
[0013]
The writing means is characterized in that writing electrodes having a plurality of convex portions are arranged in parallel on the image carrier, and the dielectric liquid applied to the surface of the image carrier is The invention is characterized in that a coating film thicker than the convex portion is formed, and the means for supplying the dielectric liquid is arranged between the transfer means on the image carrier and the developing means. Things.
[0014]
The image carrier may further include a charge eliminating unit configured to uniformly charge the image carrier, and the unit that supplies the dielectric liquid may also include a charge eliminating unit configured to equalize the charge on the image carrier. The static eliminator is made of a conductive material and is supplied with a voltage.
[0015]
The means for supplying the dielectric liquid is a developer containing the dielectric liquid, wherein the developer is supplied from the developing means onto the image carrier to form a coating film. The dielectric liquid has a viscosity in the range of 100 to 10,000 (mPa · s), and the image carrier has conductive fine particles dispersed and formed in an island shape on the surface. Things.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view showing an embodiment of an image forming apparatus according to the present invention, wherein 1 is an image forming apparatus, 2 is an image carrier, 3 is a writing head, 4 is a developing device, 4a is a developer carrier, 4b is a supply member, 5 is a transfer section, 6 is a developer, and 7 is a dielectric liquid.
[0017]
As shown in FIG. 1, an image forming apparatus 1 according to the present invention includes an image carrier 2 on which a dielectric liquid 7 is constantly applied to form an electrostatic latent image, and an image carrier 2 that comes into contact with the image carrier 2. A writing head 3 for writing an electrostatic latent image on the image carrier 2; a developing device 4 for developing the electrostatic latent image on the image carrier 2 with the developer 6 carried and conveyed on a developer carrier (developing roller) 4a; And a transfer unit 5 for transferring the toner image on the image carrier 2 developed by the developing device 4 to a transfer material such as paper.
[0018]
The writing head 3 has a relatively soft and elastic flexible base material such as FPC or PET, and an image bearing member supported by the base material and having a weak elastic restoring force due to the bending of the base material. And a writing electrode for writing an electrostatic latent image by being lightly pressed onto the body 2 and in contact therewith. The writing voltage is applied to the writing electrode itself in contact with or close to the surface of the image carrier 2.
[0019]
The image carrier 2 is made of a conductive material such as aluminum, and includes, for example, a base material, and a dielectric layer having an insulating property formed on an outer periphery of the base material. A writing electrode is supported on the dielectric layer by a base made of an FPC or the like of the writing head 3 and is in contact with the predetermined light pressure directly or through the base as described above. The carrier 2 moves (rotates) at a predetermined speed v. The writing electrodes, a predetermined high voltage V ₀ or a predetermined low voltage V ₁ is adapted to be applied are selectively switched through the substrate.
[0020]
The developing device 4 is provided to face the image carrier 2, stores a wet type developer 6, and supplies the stored developer 6, and carries the developer 6 supplied by the supply member 4 b. And a developer carrying member 4 a for conveying the image to the image carrier 2. The developer carrier 4a and the supply member 4b are elastically contacted and rotate in the opposite direction with a difference in peripheral speed to form a developer layer of a predetermined thickness on the surface of the developer carrier 4a by rubbing the developer 6. I do. At this time, the developer 6 is charged to a predetermined polarity due to friction between the developer carrier 4a and the supply member 4b. The developer carrier 4a and the image carrier 2 rotate in the forward direction, and perform non-contact development or contact development of the electrostatic latent image on the photoconductor while slipping due to a difference in peripheral speed. FIG. 1A shows a non-contact developing image forming apparatus, and FIG. 1B shows a contact developing image forming apparatus.
[0021]
The developer carrier 4a and the supply member 4b are supplied with a DC bias of Vdc from a DC bias power supply and an AC bias power supply (not shown), and the maximum value and the minimum value of the AC superimposed bias in which the AC is superimposed on the DC bias are respectively Vmax. , Vmin, and an AC superimposed bias with a voltage between the maximum value and the minimum value of the AC bias being Vpp (= Vmax−Vmin). By setting these biases appropriately, the developer does not adhere to the non-image area, there is no fog in the non-image area, there is little unevenness in the image, and the gradation is excellent, and the reproducibility of fine lines Can set good printing conditions.
[0022]
The dielectric liquid 7 is a dielectric solution that makes it difficult for air discharge to occur, prevents high frequency vibrations caused by the write head 3, and prevents wear of the image carrier 2 and the write head 3. By applying a fixed amount on the carrier 2, that is, by applying a thicker film than the electrode portion (convex portion) of the writing head 3, the electrode portion is also covered with this solution, and the effect of preventing abrasion is enhanced. be able to.
[0023]
When the dielectric liquid 7 is a low-viscosity liquid having a low viscosity, it does not have an effect of preventing high-frequency vibration by the writing head 3. An attraction force due to strong viscosity acts between them, and the effect of canceling out the influence of vibration due to the high frequency (0.1 to 3.0 kHz) applied to the write head 3 appears. However, if the viscosity is too high, the writing head 3 is pulled by the image carrier, which causes a toner image formation failure.
[0024]
Accordingly, the dielectric liquid 7 is preferably a dielectric solution such as a silicone oil having a high viscosity (100 to 10,000 mPa · s). And the like, and generally used solutions (see, for example, JP-A-11-160918 and Japanese Patent No. 2831387).
[0025]
FIG. 2 is a view showing another embodiment of the image forming apparatus according to the present invention in which the image carrier has an independent floating electrode structure, and FIG. 3 is a diagram showing the image carrier having a two-layer structure of a dielectric layer and a resistance layer. FIG. 4 is a view showing another embodiment of the image forming apparatus according to the present invention, FIG. 4 is a view showing another embodiment of the image forming apparatus according to the present invention in which the image carrier has a single-layer independent electrode structure, and FIG. FIG. 2 is an external perspective view of an image forming unit. In the figure, 2a is a base material, 2b is a dielectric layer, 2b 'is a dielectric portion, 2b "is a conductor portion, 2c is an independent floating electrode portion, 2c is a resistive layer, 3a is a base material, 3b is a write head. The contact portion 3c indicates a driver IC.
[0026]
As shown in FIG. 2, the image carrier 2 includes a base material 2a and an insulating dielectric layer 2b formed on the outer periphery of the base material 2a, and an independent floating electrode portion is provided on the surface of the dielectric layer 2b. 3, a dielectric layer 2 b having an insulating property formed on the outer periphery of the base material 2 a as shown in FIG. 3 and a resistance layer 2 c on the surface layer, and a base material 2 a as shown in FIG. 4. It may be constituted by an insulator portion 2b 'formed of an insulating dielectric layer formed on the outer periphery and a conductor portion 2b ″ made of conductive fine particles in an island shape on the surface layer. The head 3 supports the driver IC 3c on the image carrier 2 coated with the dielectric liquid 7 on an elastic and flexible base material 3a as shown in FIGS. Write head contact portion 3b at the end supporting write electrode 3b It is lightly pressed and contacts.
[0027]
FIG. 6 is a diagram showing another embodiment of the image forming apparatus according to the present invention having a dielectric liquid external coating mechanism, and FIG. 7 is a drawing showing the present invention having a dielectric liquid external coating mechanism also serving as a charge eliminating mechanism. FIG. 8 is a view showing another embodiment of the image forming apparatus, and FIG. 8 is a view showing another embodiment of the image forming apparatus according to the present invention having an external coating mechanism in which a static elimination mechanism is separately arranged. In the figure, reference numerals 81, 82, and 83 denote dielectric liquid supply units, 83a denotes a dielectric liquid injection unit, and 91 and 92 denote static elimination units.
[0028]
In the above-described embodiment, in order to apply a predetermined amount of the dielectric liquid 7 on the image carrier 2, the wet developer 6 containing the dielectric liquid 7 is stored in the developing device 4, supplied, and transported. However, the dielectric liquid 7 may be applied from outside in a part of the process on the image carrier 2. The member to which the dielectric liquid 7 is applied is preferably disposed between the transfer section 5 and the developing device 4 as shown in FIG. 6, that is, after the transfer and before the toner image development. For example, as shown in the dielectric liquid supply unit 81 in FIG. 6A, between the transfer unit 5 and the write head 3, and as shown in the dielectric liquid supply unit 82 in FIG. It is arranged between the developing device 4. Conversely, when the image carrier 2 is arranged between the developing device 4 and the transfer unit 5, that is, after the toner image is developed and before the transfer, the image carrier 2 developed by a mechanical force or a viscous force when the dielectric liquid is applied. The position of the upper toner image may be shifted.
[0029]
When the electrostatic latent image is written by the write head 3 on the surface of the image carrier 2, if the charge after transfer remains, the electrostatic latent image is disturbed by the charge and the image is deteriorated. Will be. In order to prevent such deterioration of the image, after the transfer, before the writing of the electrostatic latent image by the writing head 3, static elimination is performed to remove the charge remaining on the surface of the image carrier 2, and a uniform charge state close to 0 V is applied. Is preferable. FIG. 7A shows an example of the configuration of the dielectric liquid supply unit 83 provided with a charge elimination function for this purpose, and further, a dielectric liquid injection unit for injecting the dielectric liquid into the dielectric liquid supply unit 83. FIG. 7B shows an example of a configuration provided with 83a. On the other hand, FIG. 8 shows a configuration example in which static elimination units 91 and 92 are provided separately from the dielectric liquid supply unit 81. The static elimination unit 91 shown in FIG. 8B is an example in which the static elimination unit 93 shown in FIG. 8B is arranged between the transfer unit 5 and the dielectric liquid supply unit 81. The static elimination unit is formed of a conductive member, and the static elimination may be connected to a ground potential (earth potential) or may be a device to which a voltage is supplied to apply a constant potential.
[0030]
FIG. 9 is a view showing another embodiment of a tandem system of an image forming apparatus according to the present invention which employs charge writing and liquid development, wherein 1Y, 1M, 1C and 1K denote image forming units, and 11 denotes an image forming unit. Reference numerals 12 and 13 denote rollers, and reference numeral 14 denotes a transfer portion.
[0031]
9, the image forming apparatus 1 forms and develops a latent image by the image forming units 1Y, 1M, 1C, and 1K for each color, and the intermediate transfer of the toner image of each color to the intermediate transfer body 11 is performed. After that, the image is transferred to the recording sheet by the transfer unit 14. Each of the image forming units 1Y, 1M, 1C, and 1K includes an image carrier 2, a write head 3, and a developing device 4, forms an electrostatic latent image on the surface of the image carrier 2, performs development, and performs toner development. The image is transferred to the surface of the intermediate transfer body 11. That is, the image forming apparatus is a tandem type image forming apparatus that sequentially transfers four color toner images of yellow Y, magenta M, cyan C, and black K onto the intermediate transfer body 11 and superimposes the colors to form a full-color image. And an intermediate transfer member 11 in the shape of a circle. The intermediate transfer body 11 in the form of an endless belt is stretched between two rollers 12 and 13, and one transfer device 6 is provided at the position of the roller 13. Of the rollers 12, 13, the roller on the driving side rotates counterclockwise in the figure.
[0032]
Along the linear portion of the endless belt of the intermediate transfer body 11, the image forming units 1Y, 1M, 1C, and 1K for each color are arranged in the order of colors K, C, M, and Y from the upstream side in the rotation direction of the intermediate transfer body 11. Is established. Of course, these image forming units 1Y, 1M, 1C and 1K can be arranged in any order other than that shown. In the image forming apparatus 1 configured as described above, the black K electrostatic latent image is first written on the surface of the image carrier by the writing electrode in the black K image forming unit 1K, and then the black K electrostatic latent image is written. The latent image is developed, and a black K toner image is transferred onto the surface of the intermediate transfer body 11. Next, in the cyan C image forming unit 1C, after the electrostatic latent image of cyan C is written on the surface of the image carrier by the writing electrode, the electrostatic latent image of cyan C is developed to A cyan C toner image is transferred onto the black K toner image on the surface. Similarly, after the magenta M electrostatic latent image is written on the surface of the image carrier by the writing electrode in the magenta M image forming unit 1M, the magenta M electrostatic latent image is developed and After the magenta M toner image is transferred onto the surface of the image carrier 11 and the yellow Y electrostatic latent image is written on the surface of the image carrier by the writing electrode in the yellow Y image forming unit 1Y. The Y electrostatic latent image is developed, and the yellow Y toner image is transferred onto the surface of the intermediate transfer body 11 in a superimposed manner. Then, the transfer unit 14 forms a full-color toner image in which the toner images of the respective colors are color-matched on the recording sheet.
[0033]
In the case of the charging writing process, if dry toner is employed as in the conventional case, there is a problem that residual toner or the like after transfer adheres to the writing head portion, thereby causing an image defect or the like. By adopting the wet toner as described above, since the write head portion is always kept wet with the dielectric liquid, it is possible to prevent solids such as residual toner from sticking to the write head, It is possible to always perform stable image formation.
[0034]
[Example 1]
A dielectric liquid having a viscosity of 50 to 30000 mPa · s in SH200 oil (manufactured by Dow Corning Silicone Toray Co., Ltd.) is prepared, and these are applied to a developer carrier (solution for developer) and a dielectric liquid (applied from outside). Liquid). The liquid developer includes a charge control agent for giving a predetermined charge to the toner, a coloring pigment, and a dispersant for uniformly dispersing the coloring pigment.
[0035]
The experiment was performed with the image forming apparatus having the configuration shown in FIG. The image carrier 2 was a charge injection drum having a diameter of 30φ and had a peripheral speed of 50 to 300 (mm / sec). The signal applied to the write head was Von = 300 to 400 (V) and Voff = 0 (V), and a rectangular pulse (duty 50%) was applied to a frequency of 0.1 to 3 (kHz). As for the development, the liquid toner described above was put into a liquid developing device. The developing bias was a sine wave with Vdc = 300 to 400 (V), Vpp = 300 to 400 (V), and frequency 500 to 1500 (Hz). The experimental parameters are shown in [Table 1], and the experimental results are shown in [Table 2].
[0036]
[Table 1]

[0037]
[Table 2]

The experiment was performed at a total of 324 levels (= 6 × 2 × 9 × 3) of the experimental parameters of [Table 1]. According to the experimental results of [Table 2], one of these 324 levels of experiments was acceptable. In this case, it was marked as ○. According to this result, when the viscosity is 90 (mPa · s) or less, the writing head vibrates and toner image formation failure occurs. When the viscosity is 10100 (mPa · s) or more, the writing head is pulled by the drum. However, when the viscosity is 100 to 10000 (mPa · s), the effect of suppressing the vibration of the writing head and the effect of preventing the writing head from being pulled by the drum appears, and the effect of preventing the occurrence of the poor toner image formation occurs. Has been found to be remarkable.
[0038]
【The invention's effect】
As is apparent from the above description, according to the present invention, in an image forming apparatus that forms an electrostatic latent image on an image carrier, develops the developer image, and transfers the developer image to a transfer body, Writing means for writing an electrostatic latent image on an image carrier by applying a writing voltage in contact with or in close proximity to the image forming apparatus; and an electrostatic latent image formed on the image carrier by the writing means by supplying a developer. Developing means for developing the developer image to form a developer image, transfer means for transferring the developer image formed on the image carrier by the developing means to a transfer body, and means for supplying a dielectric liquid to the surface of the image carrier. The electrostatic latent image is written by the writing means in a state where the surface of the image carrier is coated with the dielectric liquid, so that the frictional force between the contact-type writing head (electrode) and the image carrier is reduced. The wear of the writing head and the image carrier can be prevented, and the life can be extended by reducing the amount of wear.
[0039]
The writing means is characterized in that writing electrodes having a plurality of convex portions are arranged in parallel on the image carrier, and the dielectric liquid applied to the surface of the image carrier is thicker than the convex portions. A writing film is formed, and the means for supplying the dielectric liquid is disposed between the transfer means on the image carrier and the developing means. , The abrasion of the write head and the image carrier is prevented, and good image formation by preventing leakage between the write heads becomes possible.
[0040]
The image carrier is provided with a charge eliminator for making electric charges uniform, and the means for supplying a dielectric liquid is also provided with a charge eliminator for making electric charges on the image carrier uniform, Since the unit is formed of a conductive member and is supplied with a voltage, the toner image holding performance can be improved and the size of the apparatus can be reduced.
[0041]
The means for supplying the dielectric liquid is a developer containing the dielectric liquid, wherein the developer is supplied from the developing means onto the image carrier to form a coating film. The viscosity is in the range of 100 to 10000 (mPa · s). Since the conductive particles are dispersed and formed on the surface of the image carrier, friction between the writing head and the image carrier is obtained. It is possible to reduce the force, prevent wear of the writing head and the image carrier, realize a longer life by reducing the amount of wear, improve the toner image holding performance, and reduce the size of the apparatus. It is possible to form a good image by preventing leakage between the mounting heads.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an embodiment of an image forming apparatus according to the present invention.
FIG. 2 is a diagram showing another embodiment of the image forming apparatus according to the present invention in which the image carrier has an independent floating electrode structure.
FIG. 3 is a diagram showing another embodiment of the image forming apparatus according to the present invention in which the image carrier has a two-layer structure of a dielectric layer and a resistance layer.
FIG. 4 is a diagram showing another embodiment of the image forming apparatus according to the present invention in which the image carrier has a single-layer structure of independent electrodes.
FIG. 5 is an external perspective view of an image forming unit.
FIG. 6 is a diagram showing another embodiment of the image forming apparatus according to the present invention having a mechanism for externally applying a dielectric liquid.
FIG. 7 is a diagram showing another embodiment of the image forming apparatus according to the present invention having a dielectric liquid external coating mechanism also serving as a charge removing mechanism.
FIG. 8 is a view showing another embodiment of the image forming apparatus according to the present invention having an external coating mechanism in which a static elimination mechanism is separately arranged.
FIG. 9 is a diagram illustrating another embodiment of a tandem system of the image forming apparatus according to the present invention which employs charge writing and liquid development.
FIG. 10 schematically illustrates an image forming apparatus in which a base material of a charged writing device is brought into elastic contact with an image carrier, and an electrostatic latent image is formed on the image carrier by a writing electrode provided on the base material. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Image carrier, 3 ... Writing head, 4 ... Developing device, 4a ... Developer carrier, 4b ... Supply member, 5 ... Transfer part, 6 ... Developer, 7 ... Dielectric liquid

Claims (10)

In an image forming apparatus that forms an electrostatic latent image on an image carrier, develops and forms a developer image, and transfers it to a transfer body,
A writing unit that applies a writing voltage in contact with or close to the surface of the image carrier and writes an electrostatic latent image on the image carrier;
Developing means for supplying a developer and developing the electrostatic latent image formed on the image carrier by the writing means to form a developer image;
Transfer means for transferring a developer image formed on the image carrier by the developing means to a transfer body,
Means for supplying a dielectric liquid to the surface of the image carrier, wherein the writing means writes an electrostatic latent image in a state where the dielectric liquid is applied to the surface of the image carrier. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein the writing unit includes a plurality of writing electrodes having a plurality of protrusions arranged on the image carrier in parallel. The image forming apparatus according to claim 2, wherein the dielectric liquid applied to the surface of the image carrier forms a coating film thicker than the convex portion. The image forming apparatus according to claim 1, wherein the unit that supplies the dielectric liquid is arranged between the transfer unit and the developing unit on the image carrier. The image forming apparatus according to any one of claims 1 to 4, further comprising a charge removing unit configured to make electric charges uniform on the image carrier. The image forming apparatus according to claim 1, wherein the unit that supplies the dielectric liquid also has a charge eliminating unit that equalizes charges on the image carrier. The image forming apparatus according to claim 5, wherein the static elimination unit includes a conductive member and is supplied with a voltage. The means for supplying the dielectric liquid is a developer containing the dielectric liquid, and the developer is supplied from the developing means onto the image carrier to form a coating film. Item 4. The image forming apparatus according to any one of Items 1 to 3. The image forming apparatus according to claim 1, wherein the dielectric liquid has a viscosity of 100 to 10,000 (mPa · s). The image forming apparatus according to claim 1, wherein the image carrier has conductive fine particles dispersedly formed in an island shape on a surface thereof.

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