JP4000197B2 - Electrostatic latent image liquid developing device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an electrostatic latent image liquid developing apparatus that visualizes an electrostatic latent image formed by a method such as electrophotography, electrostatic recording, or ionography using a liquid developer.
[0002]
[Prior art]
Conventionally, in an electrostatic latent image liquid developing apparatus, as a method of supplying a liquid developer to a latent image surface on an image support, unevenness is provided on the surface of a developing roller as a developer support, and liquid development is performed in a recess. A method of holding the developer and supplying it to the image support, using a sponge roller as the developer support, and supplying the liquid developer absorbed by the sponge roller to the image support by pressing the sponge roller against the image support A method of supplying the liquid developer directly to the image support without using the developer support by immersing the image support in a developer tank in which the liquid developer is stored is used.
[0003]
[Problems to be solved by the invention]
However, a conventional large electrostatic recording apparatus or the like generally uses a low-viscosity liquid developer in which toner is mixed with an organic solvent IsoparG (registered trademark: manufactured by Exxon) at a ratio of about 1 to 2%. Yes. Therefore, a high-concentration and high-viscosity liquid developer (100 to 10,000 mPa · s high-viscosity liquid developer in which toner is dispersed in high-concentration in an insulating liquid) in which the amount supplied to the image support is small is used. When used, it is not clear what method is suitable for supplying the liquid developer to the latent image surface of the image support.
[0004]
【the purpose】
The present invention has been made based on the above circumstances, and a liquid developer is applied to a latent image surface of an image support by applying a small amount of a high-concentration and high-viscosity liquid developer on the developer support with a uniform thickness. It is an object of the present invention to provide a liquid developing device for an electrostatic latent image that can uniformly supply toner.
[0005]
[Means for Solving the Problems]
  In order to achieve the above object, the electrostatic latent image liquid developing apparatus according to the first aspect of the present invention uses a toner which is a visualized particle charged with an electrostatic latent image formed on an image support. A liquid developing apparatus for developing an electrostatic latent image, wherein a liquid developer having a high viscosity of 100 to 10,000 mPa · s in which a toner is dispersed at a high concentration in an insulating liquid is brought into contact with at least a developer support. Through a first roller and a second roller that rotates at a peripheral speed faster than the peripheral speed of the first roller provided adjacent to the first roller, the thickness is 5 to 40 μm. Only high-viscosity liquid developer on the developer support, with the coating means applied on the developer support, and the distance between the developer support and the image support is less than the thickness of the liquid developer layerTheDeveloping means for contacting the image support and supplying a liquid developer to the latent image surface of the image support.The first roller is a soft roller having a hardness of 15 to 40 ° (JIS A), and the second roller is a hard roller having a hardness of 90 ° (JIS A) or more.It is characterized by this.
[0006]
According to a second aspect of the present invention, there is provided the electrostatic latent image liquid developing apparatus according to the first aspect, wherein the second roller rotates at an angular velocity faster than the angular velocity of the first roller. It is.
[0007]
According to a third aspect of the present invention, the outer diameter of the second roller is a non-integer multiple of the outer diameter of the first roller. It is a feature.
[0008]
  According to a fourth aspect of the present invention, there is provided an electrostatic latent image liquid developing apparatus for developing an electrostatic latent image, which is developed with toner, which is a visualized particle charged with the electrostatic latent image formed on the image support. A developing device having a high viscosity liquid developer of 100 to 10000 mPa · s in which a toner is dispersed in a high concentration in an insulating liquid, at least two rotating at a slower peripheral speed as the developer is closer to the developer support. The distance between the coating means for coating on the developer support and the developer support and the image support is less than or equal to the thickness of the liquid developer layer so that the thickness is 5 to 40 μm via the roller. Only high-viscosity liquid developer on supportTheA developing means for supplying the liquid developer to a latent image surface of the image support in contact with the image support.The at least two rollers are formed by alternately contacting and arranging a hard roller having a hardness of 90 ° (JIS A) or more and a soft roller having a hardness of 15 to 40 ° (JIS A).It is characterized by this.
[0009]
According to a fifth aspect of the present invention, there is provided the electrostatic latent image liquid developing apparatus according to the first, second, third, or fourth aspect, wherein the liquid developer has an insulating liquid viscosity of 0.5 to 1000 mPa · s. s, electric resistance is 10¹²Ωcm or more, surface tension is 21 dyne / cm or less, and boiling point is 100 ° C. or more.
[0010]
According to a sixth aspect of the present invention, there is provided the electrostatic latent image liquid developing apparatus according to the fifth aspect, wherein the liquid developer uses silicon oil as an insulating liquid. It is.
[0011]
According to a seventh aspect of the present invention, there is provided an electrostatic latent image liquid developing apparatus according to the first, second, third, fourth, fifth or sixth aspect, wherein the liquid developer has an average particle size of 0.1 to 5 μm. The toner is contained at a concentration of 5 to 40%.
[0012]
[Action]
  2. The electrostatic latent image liquid developing device according to claim 1, wherein the electrostatic latent image liquid developing device contacts at least a developer support.As a soft rollerAdjacent to the first roller and the first rollerAs a hard rollerBy applying the liquid developer onto the developer support via the second roller, the liquid developer on the first roller is thinly regulated at the contact portion with the second roller. Therefore, the developer support A thin liquid developer can be applied on top. Thereby, a small amount of high-concentration and high-viscosity liquid developer can be supplied to the latent image surface of the image support. In addition, when the rollers rotate at an integer multiple speed or outer diameter, the unevenness is transferred to the respective rollers, thereby causing periodic unevenness on the belt. In order to improve the periodic unevenness generated on the belt, a circumferential speed difference is given to the second roller. In other words, the liquid developer is agitated at the contact portion between the first roller and the second roller by rotating the second roller at a peripheral speed faster than the peripheral speed of the first roller. The unevenness generated in the developer layer can be prevented from being conveyed to the first roller, and the unevenness generated in the liquid developer layer on the first roller can be erased. As a result, the liquid developer can be applied evenly on the developer support, and thus a small amount of high-concentration and high-viscosity liquid developer can be supplied to the latent image surface of the image support without unevenness. Furthermore, since the liquid developer in which the toner is dispersed at a high concentration is used, the amount of liquid can be made much smaller than that of a conventional low concentration liquid developer. The liquid developer has a viscosity of 10,000 mPa · s.BeyondAs a result, it becomes difficult to stir the insulating liquid and the toner, and it becomes a problem how to make the liquid developer. Therefore, 10,000 mPa · sExceedThe liquid developer is not cost-effective and unrealistic. On the other hand, when the viscosity is less than 100 mPa · s, the toner concentration is lowered and the dispersibility of the toner is deteriorated, so that it is impossible to develop the developer in a thin layer.
  Further, this allows a high-concentration and high-viscosity liquid developer to be thinly applied on the developer support, and therefore a small amount of the high-concentration and high-viscosity liquid developer is supplied to the latent image surface of the image support. be able to. Furthermore, unlike the conventional development process, the developer support approaches the image support and the liquid developer approaches the surface of the image support, and the liquid developer layer soft contacts and the toner moves. It consists of three processes: a toner moving process and a separation process in which the developer support is separated from the image support and separated from the toner that adheres to the developer support and the toner that adheres to the image support.
[0013]
The electrostatic latent image liquid developing device according to the second aspect exhibits the same operation as the first aspect of the invention by rotating the second roller at an angular velocity faster than the angular velocity of the first roller.
[0014]
The electrostatic latent image liquid developing device according to a third aspect of the invention exhibits the same operation as that of the first aspect of the invention by setting the outer diameter of the second roller to a non-integer multiple of the outer diameter of the first roller. When the outer diameter of the second roller is an integral multiple of the outer diameter of the first roller, the first roller and the second roller always come into contact with each other at the same location. No agitation at the contact portion of the second roller.
[0015]
5. The electrostatic latent image liquid developing device according to claim 4, wherein the liquid developer is applied on the developer support via at least two rollers rotating at a slower peripheral speed as the developer is closer to the developer support. Further, since the liquid developer of the amount larger than the amount of liquid supplied to the developer support is conveyed to the roller in contact with the developer support, it is possible to apply a necessary and sufficient amount of liquid developer on the developer support. Therefore, a necessary and sufficient amount of high-concentration and high-viscosity liquid developer can be supplied to the latent image surface of the image support. The excess liquid developer conveyed to the roller that contacts the developer support is moved to the contact start position side between the roller that contacts the developer support and the roller adjacent to the roller that contacts the developer support. Retained to form a liquid reservoir. Other functions are the same as those of the first aspect of the invention.
[0016]
The electrostatic latent image liquid developing apparatus according to claim 5 can obtain a high-viscosity liquid developer by using an insulating liquid having the above characteristics. Since the liquid developer formed on the developer support is formed in a thin layer, the amount of the insulating liquid contained in the liquid developer layer is very small, and is supplied to the latent image surface of the image support. The insulating liquid contained in the liquid developer is very small. Accordingly, the amount of insulating liquid absorbed by the paper or the like at the time of transfer is extremely small, so that the problem of adhesion of the insulating liquid to the paper or the like does not particularly occur if the viscosity is 1000 mPa · s or less. However, the viscosity is 0.5 mPa · sLess thanIf it is, the volatility will be high, and it will be handled as dangerous goods and not suitable. Insulating liquid has a boiling point of 100 ° CLess thanIn this case, since the amount of evaporation increases, there is a problem in the storage method of the developer, the entire apparatus has to be sealed, and it is difficult to improve the working environment. Electrical resistance is 10¹²ΩcmLess thanIf this is the case, the insulation properties will deteriorate and toner conductivity problems will occur, making it impossible to use as a developer. Therefore, it is desirable that the electric resistance is as high as possible. Surface tension is 21 dyne / cmBeyond, Wettability worsens. Therefore, the surface tension is desirably as low as possible.
[0017]
The electrostatic latent image liquid developing apparatus according to claim 6 can obtain the insulating liquid having the characteristics according to claim 5 because the insulating liquid is mainly composed of silicon oil.
[0018]
The electrostatic latent image liquid developing device according to claim 7, wherein the liquid developer contains toner having an average particle diameter of 0.1 to 5 μm at a concentration of 5 to 40%, so that the toner in the insulating liquid is high. A liquid developer dispersed in a concentration can be obtained. Further, the resolution is improved substantially in inverse proportion to the particle size of the toner. Usually, the toner is present in a mass of about 5 to 10 on the printed paper, so the average particle size of the toner is 5 μm.Beyond, The resolution gets worse. On the other hand, the average particle size of the toner is 0.1 μmLess thanThen, the physical adhesive force increases and it becomes difficult to remove the toner during transfer.
[0019]
【Example】
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram of an electrostatic latent image liquid developing apparatus according to a first embodiment of the present invention, and FIG.FIG.FIG. 3 is a right side view of the developing device shown in FIG. 2, and FIG. 4 illustrates the operation of the coating unit of the developing device shown in FIG. FIG. 5 is a diagram showing a method of contacting adjacent rollers of the coating unit shown in FIG. 4, and FIG. 6 is a diagram for explaining the operation of the electrostatic latent image liquid developing device shown in FIG. is there.
[0020]
As shown in FIG. 1, an electrostatic latent image liquid developing apparatus 1 according to the first embodiment of the present invention includes a photoconductor 10 as an image support and a prewet for applying a prewetting liquid onto the photoconductor 10. The apparatus 20, the charging device 30 for charging the photoconductor 10, the exposure device 40 for exposing an image on the photoconductor 10, and the electrostatic latent image by supplying toner to the portion where the electrostatic latent image is formed on the photoconductor 10. A developing device 50 that visualizes the electrostatic latent image, a transfer device 60 that transfers and fixes the toner on the photoconductor 10 to a predetermined paper P, and a cleaning device 70 that removes the toner remaining on the photoconductor 10. Although not shown in the drawing, a static eliminator for neutralizing the charged photoreceptor 10 is provided.
[0021]
For the charging device 30, the exposure device 40, the cleaning device 70, and the charge removal device, the conventional techniques used in conventional electrophotographic printers can be used in most cases. Therefore, in this embodiment, the description of each of the above-described devices is omitted, and the pre-wet device 20, the developing device 50, and the transfer device 60, which are main parts of the present invention, will be described.
[0022]
The function required for the pre-wet apparatus 20 of the first embodiment is to uniformly apply a predetermined amount of the pre-wet liquid onto the photoreceptor 10. For that purpose, a method of applying the pre-wet liquid with a sponge-like material, a method of discharging the pre-wet liquid from a plurality of nozzles arranged in the width direction of the photoreceptor 10, a method of applying with a sponge roller, etc. Coating methods for other purposes can be used. The inventors of the present invention have tried various methods and confirmed that the above method is possible. The most convenient and high-performance method is a pre-wet liquid using Belita (registered trademark: Kanebo Co., Ltd.). It was the method of apply | coating. Berita is a continuous porous sponge having a three-dimensional network structure in which pores are continuous, can hold a pre-wet liquid by the volume of the pores, and when a pre-wet liquid exceeding the pore volume is supplied, The pre-wet liquid can be discharged uniformly from the surface. Note that the bell eater of this embodiment has a substantially semicircular contact surface with the photoreceptor 10.
[0023]
As shown in FIGS. 2 and 3, the developing device 50 includes a developing unit 51 and a coating unit 52. The developing unit 51 includes a developing belt 510 that is a developer support, driving rollers 512a and 512b that rotate and drive the developing belt 510 and hold a part of the developing belt 510 in contact with the photoconductor 10. A scraping blade 514 that removes the liquid developer remaining on the developing belt 510 and a support roller 516 that supports the developing belt 510 from the back surface of the developing belt 510 when a conveyance roller 522a described later contacts the developing belt 510. . The coating unit 52 includes coating devices 52a, 52b, 52c, and 52d that apply a liquid developer to the surface of the developing belt 510.
[0024]
The developing belt 510 is rotationally driven in a direction opposite to the rotational direction of the photoconductor 10 by driving rollers 512a and 512b. As the developing belt 510, a flexible belt member such as a resin belt such as a seamless nickel belt or a polyimide belt is used. The developing belt 510 must be capable of applying a developing bias. Therefore, in the case of using a resin belt, it is necessary to add conductive fine particles to lower the electric resistance value or to conduct conductive processing on the surface of the belt.
[0025]
The coating devices 52a to 52d store and discharge the liquid developer, a bellows pump 520, transport rollers 522a, 522b, and 522c that transport the liquid developer discharged by the bellows pump 520 to the developing belt 510, and an adjustment roller 522d. And a separating / contacting device 524 for separating and contacting the conveying roller 522a with the developing belt 510. The bellows pump 520a of the coating device 52a has a liquid developer containing yellow toner, the bellows pump 520b of the coating device 52b has a liquid developer containing magenta toner, and the bellows pump 520c of the coating device 52c has a cyan toner. The liquid developer containing the black toner is stored in the bellows pump 520d of the coating device 52d.
[0026]
The conveyance roller 522a is provided so as to abut on the conveyance roller 522b, the conveyance roller 522b is abutted against the conveyance roller 522c, and the conveyance roller 522c is provided so as to abut on the adjustment roller 522d. The transport roller 522a is driven by the developing belt 510 at the same peripheral speed as the developing belt 510, the transport roller 522b is driven by the transport roller 522a at an angular speed higher than the angular speed of the transport roller 522a, and the transport roller 522c is The adjustment roller 522d rotates in the direction driven by the conveyance roller 522b at the same angular velocity as the conveyance roller 522b, and the adjustment roller 522d rotates in the direction driven by the conveyance roller 522c at the same angular velocity as the conveyance roller 522c.
[0027]
The transport roller 522b and the adjustment roller 522d are hard rollers having a hardness of 60 ° (JIS A) or more, and the transport roller 522a and the transport roller 522c are 60 ° (JIS A).) Less thanEach of these soft rollers is used. Hard roller with hardness of 60 ° (JIS A) or higher and hardness of 60 ° (JIS A)Less thanThe reason why the soft rollers are arranged in contact with each other alternately is that the soft rollers are elastically deformed to form a nip width t at the contact portion with the adjacent hard roller, as shown in FIG. . In order to elastically deform the soft roller, the harder the harder the better. Therefore, the hardness of the hard roller is desirably 90 ° (JIS A) or more. For rollers with a hardness of 90 ° (JIS A) or higher, ULTRA-S (manufactured by Miyagawa Roller) made of urea resin, and ceramic rollers (made by Nippon Steel Corporation) made of ceramics mainly composed of alumina ), A resin roller such as a roller formed of ebonite. Further, when the pressing force of the soft roller to the hard roller is strong, a high torque is required to rotate each roller. For this reason, it is preferable that the soft roller be elastically deformed with a weak pressing force. Therefore, the hardness of the soft roller is desirably 40 ° (JIS A) or less. However, hardness is 15 ° (JIS A)Less thanThen, it becomes impossible to maintain a constant shape, and it becomes difficult to form a constant nip width at the contact portion with the hard roller. Examples of rollers having a hardness of 15 ° to 40 ° (JIS A) include BEET (manufactured by Miyagawa Roller) made of synthetic resin, and rollers made of NBR (acrylonitrile-butadiene rubber). Note that the transport rollers 522a to 522c are preferably oleophilic, since it is necessary to apply the liquid developer described later thinly and uniformly on the surface.
[0028]
As shown in FIG. 5, a disc wheel 526a having the same outer diameter as that of the conveying roller 522b is provided on both sides of the conveying roller 522b, and a circle having the same outer diameter as that of the adjusting roller 522d is provided on both sides of the adjusting roller 522d. A plate wheel 526a is provided. Further, a disc wheel 526b having an outer diameter slightly smaller than the outer diameter of the conveying roller 522a is provided on both sides of the conveying roller 522a, and a disc wheel 526b having an outer diameter slightly smaller than the outer diameter of the conveying roller 522c is provided on both sides of the conveying roller 522c. Is provided. Then, by bringing the adjacent disc wheel 526a and the disc wheel 526b into contact with each other, the distance between the axes of the adjacent transport rollers is made shorter than the total radius of the adjacent transport rollers, and the transport roller 522c and the adjustment roller The inter-axis distance of 522d is shorter than the sum of the radii of the conveying roller 522c and the adjusting roller 522d. As a result, the adjacent conveyance roller and conveyance roller 522c and adjustment roller 522d are brought into contact with each other with a constant pressing force. In this embodiment, the conveyance rollers 522a to 522c and the adjustment roller 522d have an outer diameter of φ20 mm, the disc wheel 526a has an outer diameter of φ20 mm, and the disc wheel 526b has an outer diameter of φ19 mm. . The disc wheel may be a cylindrical roller.
[0029]
The separation / connection device 524 includes arms 524a and 524a. A conveyance roller 522a and a conveyance roller 522b are fixed to the arms 524a and 524a. The arms 524a and 524a are rotated around the transport roller 522b by a driving device (not shown). As a result, the conveying roller 522a is brought into contact with the developing belt 510.
[0030]
The transfer device 60 includes an intermediate transfer belt 610 that is an intermediate transfer member, and driving rollers 612a and 612b that rotate and drive the intermediate transfer belt 610 and a part of the intermediate transfer belt 610 in contact with the photoconductor 10. , 612 c, a secondary transfer roller 614 that is a secondary transfer member installed so as to contact the intermediate transfer belt 610, and a scraping blade 616 that removes toner remaining on the intermediate transfer belt 610.
[0031]
The intermediate transfer belt 610 is rotationally driven in a direction opposite to the rotational direction of the photoconductor 10 by driving rollers 612a, 612b, and 612c. The secondary transfer roller 614 is pressed against the intermediate transfer belt 610 through the paper P. A fixing heater 618 for heating the paper P is provided inside the driving roller 612c.
[0032]
Next, the image forming material used in the first embodiment of the present invention will be described. The liquid developer used in the first embodiment includes a resin, which is a binder such as an epoxy, a charge control agent that gives a predetermined charge to the toner, a color pigment, a toner that uniformly disperses the toner, and a carrier liquid. It consists of. The construction of the toner is basically the same as that used in conventional liquid developers, but their formulation has been changed to be compatible with silicone oil to adjust charging characteristics and dispersibility. The smaller the average particle diameter of the toner, the better the resolution. However, when the particle diameter is small, the physical adhesive force increases and it becomes difficult to peel off when transferring. For this reason, in the first embodiment, the average particle diameter of the toner is adjusted so that the center is about 2 to 4 μm for the purpose of improving transferability.
[0033]
The viscosity of the liquid developer is determined by the carrier liquid used, the resin, the color pigment, the charge control agent, etc., and their concentrations. In the first embodiment, the experiment was performed by changing the viscosity in the range of 50 to 6000 mPa · s and the toner concentration in the range of 5 to 40%.
[0034]
As the carrier liquid, a low viscosity liquid such as dimethylpolysiloxane oil or cyclic polydimethylsiloxane oil exhibiting high electrical resistance is used. Since the liquid developer layer formed on the developing belt 510 is formed in a thin layer, the amount of carrier liquid contained in the liquid developer layer is very small. Accordingly, since the amount of carrier liquid contained in the liquid developer supplied to the latent image surface of the photoconductor 10 is extremely small, the amount of carrier liquid absorbed by paper or the like during transfer is extremely small. For this reason, if the viscosity is 1000 mPa · s or less, almost no carrier liquid remains after fixing.
[0035]
According to the experiments by the present inventors, when an image-drawing experiment was performed using DC344 of Dow Corning, Inc., which has a viscosity of 2.5 mPa · s, the carrier liquid remaining on the paper after fixing was observed. I couldn't. However, since the volatility is high, the developing device has to be sealed. In addition, when the image formation experiment was performed using DC345 of US Dow Corning Co., Ltd. having a viscosity of 6.5 mPa · s in the carrier liquid, as in the case of the image formation experiment using DC344, after fixing, on the paper The carrier liquid remaining in was not observed. However, since the volatility is high, the developing device has to be sealed. Furthermore, when an image forming experiment was performed using KF-96-20 manufactured by Shin-Etsu Silicon Co., Ltd., whose viscosity was 20 mPa · s, no carrier liquid remained on the paper after fixing. Further, since the volatility is not so high, it is not necessary to make the developing device in a sealed structure. DC344, DC345 and KF-96-20 are generally used in cosmetics and have high safety such as toxicity. There are many types of carrier liquids such as KF9937 manufactured by Shin-Etsu Silicon Co., Ltd., and any of them may be selected as long as electrical resistance, evaporation characteristics, surface tension, safety and the like are satisfied.
[0036]
Further, in experiments conducted by the present inventors, when surface tension is large, fog or a lump of toner may adhere to the photoconductor 10, and it is experimentally 21 dyne / cm.BeyondIt turns out that there is a problem with image quality.
[0037]
The electrical resistance value has a problem of toner charging stability.¹⁴Ωcm or more is desirable. 10 at a minimum¹²Ωcm or more is necessary. In the description of the first embodiment, in view of these experimental results, an example using a DC 345 that is inexpensive and easily available is shown.
[0038]
The pre-wet liquid is required to evaporate easily at the time of fixing without disturbing the electrostatic latent image formed on the photoconductor 10 so that fog or a lump of toner does not adhere to the photoconductor 10. Examples include DC344, DC200-0.65, -1.0, -2.0 of Dow Corning, USA, KF96L-1, KF9937, etc. of Shin-Etsu Silicon. In general, it is necessary to select a highly evaporable silicone oil.
[0039]
In the experiment conducted by the present inventors, the liquid was dried by development, transfer, and fixing without any problem in the range of the liquid viscosity of 0.5 to 3 mPa · s, but somewhat in the range of 5 mPa · s to 6 mPa · s. There was a tendency for time and temperature to be required for drying the liquid during fixing. At 10 mPa · s, the energy required for drying becomes too large, which is not general. 0.5 mPa · sLess thanIf it is, the volatility will be high, and it will be handled as dangerous goods and is not suitable. In addition, due to the effect of heating the paper, the boiling point needs to be 250 ° C. or lower.
[0040]
The surface tension should be as low as possible in order to eliminate the adhesion between the liquid developer and the photosensitive member 10 and improve the releasability to prevent image smearing and fogging, and to improve the image resolution and fogging. According to the experiments by the present inventors, it is necessary to select a value of about 20 to 21 dyne / cm which is lower than the limit.
[0041]
If the electrical resistance is low, the insulating property is deteriorated and the electric charge is leaked. Therefore, it is necessary to use as high as possible. 10 experimentally¹⁴About Ωcm or more is desirable. 10 at a minimum¹²Ωcm is required.
[0042]
Next, the operation of the electrostatic latent image developing apparatus according to the first embodiment of the present invention will be described. First, as illustrated in FIG. 6A, the photosensitive member 10 is charged by the charging device 30. Generally, a corona discharger is used for the charging device 30. Next, an image is exposed on the charged photoreceptor 10. For example, the image is exposed by a laser scanner to form an electrostatic latent image on the surface of the photoreceptor 10. As shown in FIG. 6B, the portion exposed to the light of the laser scanner becomes conductive, so that the charge disappears, and the portion not exposed to the light remains as an electrostatic latent image that is an image of the charge.
[0043]
Next, as shown in FIG. 6C, the pre-wet liquid described above is applied onto the photoconductor 10 by the pre-wet apparatus 20.
[0044]
Next, the electrostatic latent image is visualized by the developing device 50. As shown in FIG. 4, the liquid developer discharged to the contact start position between the adjustment roller 522d and the conveyance roller 522c by the bellows pump 520 is a nip (elasticity) formed at the contact portion between the adjustment roller 522d and the conveyance roller 522c. It is regulated to a uniform thickness by the deformed portion) and applied onto the conveying roller 522c. The liquid developer applied on the conveyance roller 522c is further regulated to a uniform thickness by the nip formed at the contact portion between the conveyance roller 522c and the conveyance roller 522b, and is applied onto the conveyance roller 522b. The liquid developer applied on the conveyance roller 522b is stirred at the contact portion between the conveyance roller 522b and the conveyance roller 522a due to a difference in peripheral speed between the conveyance roller 522b and the conveyance roller 522a, and at the same time, the conveyance roller 522b and the conveyance roller 522a. The nip formed at the abutting portion is further regulated to a uniform thickness and applied onto the conveying roller 522a. Thus, the liquid developer applied with a uniform thickness on the conveying roller 522a via the plurality of rollers is thinly and evenly applied on the surface of the developing belt 510, whereby the liquid developer is thinly applied on the developing belt 510. Form a layer. The thickness of the thin layer formed on the developing belt 510 can be adjusted by changing the nip width t. In the developing device 50, any of the coating devices 52 a to 52 d is brought into contact with the developing belt 510 by the separation / contact device 524. As a result, a liquid developer containing toner of any one of yellow, magenta, cyan and black can be applied thinly and uniformly on the developing belt 510.
[0045]
Next, as shown in FIG. 6D, the liquid developer layer formed on the developing belt 510 is brought close to the electrostatic latent image formed on the surface of the photoreceptor 10 and charged by electrostatic force. The toner thus moved is moved onto the photoreceptor 10. As a result, a toner image is formed on the photoreceptor 10.
[0046]
Next, as illustrated in FIG. 6E, the toner image formed on the photoreceptor 10 is primarily transferred onto the intermediate transfer belt 610 by the transfer device 60. On the other hand, the liquid developer remaining on the photoconductor 10 is removed from the photoconductor 10 by the cleaning device 70, and thereafter, the photoconductor 10 is discharged by a charge removal device (not shown). Then, after switching the coating devices 52a to 52d that are in contact with the developing belt 510 by the separation / contact means 524, the cycle from charging to discharging is repeated again, whereby yellow, magenta, cyan, and black are transferred onto the intermediate transfer belt 610. The toner images are transferred one after the other. As a result, a toner image corresponding to colorization is formed on the intermediate transfer belt 610.
[0047]
Next, as shown in FIG. 6F, the toner image corresponding to the coloration formed on the intermediate transfer belt 610 is secondarily transferred to the paper P as a recording medium and fixed at the same time by the transfer device 60. The toner image corresponding to the coloration formed on the intermediate transfer belt 610 moves onto the paper P and is secondarily transferred by the pressing force of the secondary transfer roller 614 to the intermediate transfer belt 610 and heat from the fixing heater 618. At the same time, it melts and fixes thermally. As a result, a color image can be formed on the paper P.
[0048]
FIGS. 7 to 11 are diagrams for explaining in detail the development process of one embodiment of the present invention, FIG. 7 is a diagram for explaining the whole development process, and FIG. 8 is a view showing the approach process. FIG. 9 is a diagram showing how the toner moves, FIG. 10 is a diagram showing a non-image portion separation process, and FIG. 11 is a diagram showing an image portion separation process. Unlike the conventional developing process, the developing process of the first embodiment includes an approaching process in which the developing belt 510 approaches the photoreceptor 10 and the liquid developer approaches the surface of the photoreceptor 10 as shown in FIG. The toner moving process in which the liquid developer layer and the pre-wet liquid layer are in soft contact with each other to move the toner, the toner that the developing belt 510 leaves from the photoconductor 10 and adheres to the developing belt 510 and the toner that adheres to the photoconductor 10 It is thought that it consists of three processes:
[0049]
In the approaching process, since the developing belt 510 is formed of a flexible belt member, as shown in FIG. 8, the liquid developer layer on the developing belt 510 and the pre-wet layer on the photoreceptor 10 are in contact with each other. The contact pressure at the time is dispersed, and the high-viscosity liquid developer composed of the carrier liquid and toner and the pre-wet liquid are in soft contact. As a result, the pre-wet liquid having a low viscosity is slightly pushed back and forth, and a pool of the pre-wet liquid is generated.
[0050]
In the toner movement process, as shown in FIG. 9, in the image portion, the toner on the developing belt 510 is pre-wet liquid mainly by the Coulomb force due to the electric field formed between the charge on the photoreceptor 10 and the developing belt 510. Move through the layers to the latent image plane. On the other hand, in the non-image portion, the toner on the developing belt 510 does not move to the surface of the photoconductor 10 because the surface of the photoconductor 10 and the liquid developer layer are separated by the pre-wet liquid layer.
[0051]
In the separation process, the liquid developer remains on the developing belt 510 in the non-image area as shown in FIG. When the two layers are separated at the interface between the pre-wet liquid layer and the liquid developer layer, a part of the pre-wet liquid layer having a low viscosity is transferred to the liquid developer layer and separated. Therefore, the separation point of the two layers is considered to be inside the pre-wet liquid layer. On the other hand, in the image portion, as shown in FIG. 11, since the toner moved to the surface of the photoconductor 10 pushes off the pre-wet liquid layer, the pre-wet liquid layer is located on the toner layer, and both of them are the pre-wet liquid layer. Separate inside. A part of the carrier liquid remaining after the toner moves and a part of the pre-wet liquid form a layer on the developing belt 510.
[0052]
FIG. 12 is a diagram for explaining the significance of thinning the liquid developer. If the liquid developer layer applied on the developing belt 510 is too thick, the viscosity of the liquid developer is high, so that a group of toners that are about to move from the developing belt 510 to the surface of the photosensitive member 10 by electrostatic force are surrounded by the liquid developer layer. A cluster is formed without breaking the viscosity of the toner positioned, and the toner moves to the surface of the photoconductor 10. For this reason, the toner moves excessively, the toner image formed on the photoreceptor 10 is disturbed, and image noise is generated. In order to suppress the occurrence of this cluster, it is necessary to suppress the layer thickness of the liquid developer layer to a minimum value at which development can be sufficiently performed.
[0053]
FIG. 13 is a diagram showing the development roller as a development support and the photoreceptor 10 in hard contact, and FIG. 14 is a diagram for explaining the soft contact of the first embodiment. As described above, in the development process of the first embodiment, the function of the pre-wet liquid layer for image formation is important. Therefore, an important requirement in the development process is to maintain the two-layer state of the pre-wet liquid layer and the liquid developer layer. Since the two-layer state cannot be maintained when the developing roller and the photosensitive member are brought into hard contact as shown in FIG. 13, in the first embodiment, as shown in FIG. The pre-wet liquid is obtained by dispersing the contact pressure when the pre-wet liquid layer on the photoconductor 10 and the liquid developer layer on the development belt 510 are in contact with each other. The layer and the liquid developer layer are maintained in a two-layer state.
[0054]
Next, the layer thickness of the liquid developer layer on the developing belt 510 and the layer thickness of the pre-wet liquid layer on the photoreceptor 10 will be described. The layer thickness of the liquid developer layer on the developing belt 510 needs to be reduced when the viscosity of the liquid developer is 50 to 100 mPa · s or more, particularly when the viscosity is 500 mPa · s or more. Ideally, it is slightly thicker than the layer thickness that satisfies the toner development amount required for development (that is, the density when solid black is produced). This is because when a liquid developer having a high viscosity is used, the electrostatically selected toner is moved onto the photoconductor 10 due to the viscosity of the liquid and moves to the photoconductor 10 at the time of development. This is because the toner image formed in this way is disturbed. In the experiments by the present inventors, a good image was obtained with a layer thickness of about 5 μm for the liquid developer having a high toner concentration and with a layer thickness of about 40 μm for the low developer. In particular, when a liquid developer having a toner concentration of 20 to 30% was used, a good image quality was obtained when the layer thickness of the liquid developer was about 20 μm.
[0055]
The thickness of the pre-wet liquid layer on the photoreceptor 10 has an optimum value depending on the viscosity and surface tension of the selected pre-wet liquid. If it is too thin, the toner on the developing belt 510 irregularly moves on the photoconductor 10 and the toner image formed on the photoconductor 10 is disturbed. As the amount of the pre-wet liquid is increased, the disturbance of the toner image is improved and the optimum value is confirmed. As the amount is further increased, the toner on the photoconductor 10 flows and the toner image on the photoconductor 10 tends to be blurred. In the experiment using DC344, good results were obtained with a thickness of 5 to 30 μm. For those having a lower viscosity than this, a result that is thinner or thicker than this result can be obtained. However, for high viscosity ones, the optimum value tends to narrow.
[0056]
As a result of the image output experiment under the above-described conditions, the optimum range of the viscosity of the liquid developer and the pre-wet liquid for the electrostatic latent image developing apparatus of the first embodiment is from 100 mPa · s for the liquid developer. It was found that the 6000 mPa · s and the pre-wet liquid was between 0.5 mPa · s and 5 mPa · s. In addition, DC200 series made by Dow Corning was used for the silicon oil of the prewetting liquid, and DC345 made by the same company was used for the carrier liquid of the developer.
[0057]
According to the first embodiment of the present invention, the conveyance roller 522a and the conveyance roller 522a that are soft rollers, the conveyance roller 522b that is a hard roller, and the adjustment roller 522d are arranged in contact with each other in the order of 522a to 522d. The liquid developer supplied to the contact start position between the roller 522d and the transport roller 522c is formed at the nip formed at the contact portion between the adjustment roller 522d and the transport roller 522c, and at the contact portion between the transport roller 522c and the transport roller 522b. The nip and the nip formed at the contact portion between the conveyance roller 522b and the conveyance roller 522a are regulated to have a uniform thickness and are thinly applied onto the conveyance roller 522a. As a result, the high-concentration and high-viscosity liquid developer can be applied thinly on the developing belt 510, and thus a small amount of the high-concentration and high-viscosity liquid developer can be supplied to the latent image surface of the photoreceptor 10. .
[0058]
If the liquid developer is applied on the developer support via two or more rollers, the liquid developer can be applied thinly on the developer support. However, when the hard rollers are adjacent to each other, the layer thickness of the liquid developer layer is regulated by a minute gap formed between the adjacent hard rollers, so that high accuracy is required when setting each roller. Further, in order to make the thickness of the liquid developer layer uniform, the surface accuracy of the roller surface must be improved.
[0059]
Further, according to the first embodiment, the liquid developer is stirred at the contact portion between the conveyance roller 522a and the conveyance roller 522b by rotating the conveyance roller 522b at an angular velocity faster than the angular velocity of the conveyance roller 522a. Unevenness generated in the liquid developer layer on the transport roller 522b and the liquid developer layer on the transport roller 522c can be prevented from being transported to the transport roller 522a. When the transport roller 522a comes into contact with the developing belt 510 for the first time, the liquid developer on the transport roller 522a moves on the developing belt 510 more than usual. For this reason, as shown in FIG. 16, a belt-like first unevenness 12a (a portion with a thick layer) is generated on the developing belt 510, and a corresponding belt-like unevenness (a portion with a thick layer) is formed on the transport roller 522a. ) Occurs. Here, when the peripheral speed of the transport roller 522a and the peripheral speed of the transport roller 522a are the same, the belt-shaped unevenness on the transport roller 522a causes the corresponding belt-shaped belt to be formed on the developing belt 510 every time the transport roller 522a makes one rotation. Second unevenness 12b (a portion having a thin layer thickness) occurs. On the other hand, in the case of the present embodiment, the liquid developer is agitated at the contact portion between the conveyance roller 522a and the conveyance roller 522b, so that the strip-like unevenness generated on the conveyance roller 522a can be eliminated. It is possible to prevent the unevenness 12b corresponding to the belt-shaped unevenness from occurring on the belt 510. As a result, the liquid developer can be applied uniformly and uniformly on the developing belt 510. Therefore, a small amount of high-concentration and high-viscosity liquid developer can be uniformly supplied to the latent image surface of the photoreceptor 10 without unevenness. Can do.
[0060]
Furthermore, according to the first embodiment, the use of silicon oil as the carrier liquid for the liquid developer has the following advantages over the conventional one.
[0061]
Conventional liquid developers generally use IsoparG (registered trademark: manufactured by Exxon) as a carrier liquid. Since Isopar has a resistance value that is not as high as that of silicone oil, when the toner concentration is increased, that is, when the interparticle distance is decreased, the chargeability of the toner is deteriorated. Therefore, in the case of Isopar, there is a limit to the toner density. On the other hand, the silicone oil used in the first embodiment has a sufficiently large resistance value, so that the toner density can be increased. In general, in the case of Isopar, the dispersion state of the toner is good. Therefore, even when the toner concentration is 1 to 2%, the toners repel each other, so that the toner is uniformly dispersed. On the other hand, when the toner concentration is 1 to 2%, silicone oil does not have good dispersibility and soon precipitates. However, when the toner concentration is 5 to 40%, the toner is densely packed and stably dispersed. Therefore, in the first embodiment, a high-viscosity liquid developer in which toner is dispersed at a high density is used. Thereby, compared with the conventional low concentration liquid developer, the amount of the developer can be greatly reduced, and the apparatus can be downsized. Furthermore, since the liquid developer of the first embodiment is a high-viscosity liquid, it is easier to store and handle than the conventional low-viscosity liquid developer and powder developer.
[0062]
As described above, Isopar used in a conventional liquid developer has high volatility and emits a foul odor, which causes a problem that it not only deteriorates the working environment but also causes pollution. On the other hand, the silicone oil used in the first embodiment is a safe liquid and odorless, as is apparent from the fact that it is used for cosmetics. The work environment can be improved, and pollution problems do not occur.
[0063]
In the first embodiment, the conveyance roller 522a is rotated at an angular velocity slower than the angular velocity of the conveyance roller 522b. However, the present invention is not limited to this, and the conveyance roller 522a is replaced by the conveyance roller 522b. It may be anything rotated at a peripheral speed slower than the peripheral speed. For example, when the outer diameter of the transport roller 522b is a non-integer multiple of the outer diameter of the transport roller 522a, the transport roller 522a may be rotated at the same angular velocity as the transport roller 522b. When the outer diameter of the transport roller 522b is an integral multiple of the outer diameter of the transport roller 522a, the transport roller 522a and the transport roller 522b always come into contact with each other at the same location, so that the liquid developer on the transport roller 522a is transported by the transport roller 522a. And the degree of stirring at the contact portion of the conveying roller 522b is low.
[0064]
Next, a second embodiment of the present invention will be described. The electrostatic latent image liquid developing device of the second embodiment is different from that of the first embodiment in that the conveying roller 522a is the same as the peripheral speed of the developing belt 510 in the developing device 50 shown in FIGS. In the direction to follow the developing belt 510 at the peripheral speed, the transport roller 522b is in the direction to follow the transport roller 522a at a peripheral speed faster than the peripheral speed of the transport roller 522a, and the peripheral speed in the transport roller 522c is faster than the peripheral speed of the transport roller 522b. The adjustment roller 522d is rotated in the direction driven by the conveyance roller 522b and at the peripheral speed faster than the conveyance roller 522c. Other configurations are the same as those of the first embodiment. In the second embodiment of the present invention, those having the same functions as those of the first embodiment are designated by the same reference numerals or corresponding reference numerals, and detailed description thereof is omitted.
[0065]
According to the second embodiment of the present invention, the transport rollers 522a to 522c are rotated at a slow peripheral speed in the order of 522a to 522d, so that the liquid developer more than the amount of liquid supplied by the transport roller 522a to the developing belt 510 is supplied. It can be conveyed to the conveyance roller 522a. When the peripheral speeds of the conveying rollers 522a to 522c are the same, there is a limit to the amount of liquid that the conveying roller 522a supplies to the developing belt 510. Therefore, in this case, the conveying roller 522a is first applied to the developing belt 510 as shown in FIG. The liquid developer layer 14a having a sufficient layer thickness can be formed on the developing belt 510 until it makes one rotation after contact, but after the conveyance roller 522a makes one rotation, a sufficient amount of liquid is formed on the developing belt 510. Liquid developer cannot be supplied, and the liquid developer layer 14b having a thinner thickness than the liquid developer layer 14a is formed. On the other hand, in the case of this embodiment, since the liquid developer more than the amount of liquid supplied to the developing belt 510 by the conveying roller 522a can be conveyed to the conveying roller 522a, one rotation after the conveying roller 522a makes one rotation. The liquid developer can be applied onto the developing belt 510 with the same layer thickness as before. As described above, according to the present exemplary embodiment, a high-concentration and high-viscosity liquid developer having a necessary and sufficient amount can be supplied to the latent image surface of the photoconductor 10. The excess liquid developer transported to the transport roller 522a is held on the contact start position side of the transport roller 522a and the transport roller 522b to form a liquid pool. Other operations and effects are the same as in the first embodiment.
[0066]
The present invention is not limited to the above embodiments, and various modifications are possible within the scope of the gist. For example, in each of the above-described embodiments, the application device has been described as applying the liquid developer onto the developing belt 510 via the three conveying rollers 522a to 522c. However, the present invention is not limited to this. Absent. The application device may be any device that applies a liquid developer onto the developing belt via at least two rollers.
[0067]
Further, a disc wheel 526a having the same outer diameter as the roller outer diameter is provided on both sides of the conveyance roller 522b and the adjustment roller 522d, and a disc wheel 526b having an outer diameter slightly smaller than the roller outer diameter is provided on both sides of the conveyance roller 522a and the conveyance roller 522c. Although each provided and the adjacent disc wheel 526a and the disc wheel 526b abutting each other was explained, the present invention is not limited to this, and the distance between the axes of the adjacent transport rollers is adjacent. What is necessary is that the distance between the axes of the conveyance roller 522c and the adjustment roller 522d is shorter than the total of the radii of the conveyance roller 522c and the adjustment roller 522d. For example, as shown in FIG. 15, a disc wheel 526c having an outer diameter slightly smaller than the roller outer diameter may be provided on both sides of the soft roller, and the disc wheel 526c may be in contact with an adjacent hard roller.
[0068]
Further, a coating device 52a for applying a liquid developer containing yellow toner to the developing belt 510, a coating device 52b for applying a liquid developer containing magenta toner to the developing belt 510, and a liquid developer containing cyan toner. In the above description, the coating device 52c for coating the developing belt 510 and the coating device 52d for coating the developing belt 510 with a liquid developer containing black toner have been described. However, the present invention is not limited to this. . What is necessary is just to provide at least one coating device for applying a liquid developer containing toner of a desired color on the developing belt via at least two rollers as required.
[0069]
In each of the above-described embodiments, the developer belt 510 configured by a belt member having flexibility as the developer support has been described. However, the present invention is not limited to this. The developer support may be a roller formed of a conductive member such as metal. However, in this case, the liquid developer layer formed on the developing roller and the pre-wet liquid layer formed on the image support are brought into contact with each other while maintaining the two-layer state, and both are brought into the interior of the pre-wet liquid layer. In order to separate them, the image support is made of a flexible belt member, or the development roller is installed so that a minute gap is formed between the development roller and the image support. There is a need to.
[0070]
Further, in each of the above embodiments, the case where the organic photoreceptor 10 is used as the image support has been described, but the present invention is not limited to this. The image support may be various photoreceptors used in the Carlson method, or an insulating recording layer formed on a conductor that directly forms an electrostatic latent image such as ionography, or an electrostatic recording paper such as an electrostatic plotter.
[0071]
In each of the above embodiments, as a transfer device, the toner image formed on the photoconductor 10 is primarily transferred onto the intermediate transfer belt 610 as an intermediate transfer body, and then primary transferred onto the intermediate transfer belt 610. In the above description, the toner image is secondarily transferred onto the paper P to form an image on the paper P. However, the present invention is not limited to this, and the transfer device is formed on the image support. Any toner image can be used as long as the toner image can be transferred to a recording medium. For example, in a monochrome liquid developing apparatus, a toner image formed on an image support may be directly transferred onto a recording medium without being primarily transferred onto an intermediate transfer member.
[0072]
Further, in each of the above-described embodiments, the description has been given of the case where the image is exposed on the image support charged by the exposure device 40 and then the pre-wet liquid is applied on the image support by the pre-wet device 20. The invention is not limited to this, and the application of the pre-wet liquid only needs to be performed prior to the development step.
[0073]
Further, the present invention is not limited to each of the above embodiments, and if a pre-wet liquid layer is formed and the layer thickness of the liquid developer is 5 to 40 μm, the viscosity of the high viscosity developer is 10,000 mPa. -S may be sufficient. At present, it is considered that a developer having a high viscosity of 6000 mPa · s or higher is difficult to stir between the carrier liquid and the toner, so that it is not cost effective. Good. Those having a viscosity exceeding 10,000 mPa · s are not realistic. The pre-wet liquid has a viscosity of 0.5 to 5 mPa · s and an electric resistance of 10¹²If it is Ωcm or more, the boiling point is 100 to 250 ° C., and the surface tension is 21 dyne / cm or less, it does not have to be mainly composed of silicon oil. Further, the carrier liquid of the liquid developer is not limited to silicon oil.
[0074]
In each of the above-described embodiments, the liquid latent image developing method having a pre-wet process has been described. However, the present invention is not limited to this. For example, if the surface of the image support is coated with a releasable material, the pre-wetting process is not particularly required.
[0075]
【The invention's effect】
As described above, according to the first aspect of the present invention, the liquid developer is applied to the developer support via at least the first roller in contact with the developer support and the second roller adjacent to the first roller. By applying, the liquid developer on the first roller is thinly regulated at the contact portion with the second roller, so that the liquid developer can be applied thinly on the developer support, and thus a small amount The liquid developer having a high concentration and a high viscosity can be supplied to the latent image surface of the image support, and the second roller is rotated at a peripheral speed faster than the peripheral speed of the first roller. Is agitated at the contact portion between the first roller and the second roller, so that unevenness generated in the liquid developer layer on the second roller can be prevented from being conveyed to the first roller and the first roller Unevenness in the upper liquid developer layer can be erased As a result, the liquid developer can be uniformly applied onto the developer support without unevenness, and therefore a small amount of high-concentration and high-viscosity liquid developer can be uniformly supplied to the latent image surface of the image support. Furthermore, by developing a thin developer with a high-viscosity liquid developer in which toner is dispersed at a high concentration, the electrostatic latent image can be easily reduced in size with high resolution and reduced in pollution. A liquid developing device can be provided.
[0076]
According to the second aspect of the present invention, with the above-described configuration, it is possible to provide an electrostatic latent image liquid developing device having the same effect as that of the first aspect of the present invention.
[0077]
According to the third aspect of the present invention, an electrostatic latent image liquid developing device having the same effect as that of the first aspect of the invention can be provided by adopting the above configuration.
[0078]
According to the fourth aspect of the present invention, the developer support is applied to the developer support via at least two rollers that rotate at a slower peripheral speed as the developer is closer to the developer support. In addition to the effect of the invention of claim 1, in addition to the effect of the invention of claim 1, a liquid having a necessary and sufficient amount of liquid is transported to the roller that contacts the developer. Thus, it is possible to provide an electrostatic latent image liquid developing apparatus capable of applying a developer and supplying a necessary and sufficient amount of liquid developer to the latent image surface of the image support.
[0079]
According to the fifth aspect of the present invention, in addition to the effect of the first aspect of the present invention, the liquid developing device for an electrostatic latent image having good wettability of the liquid developer is provided. Can do.
[0080]
According to the sixth aspect of the present invention, in addition to the effect of the fifth aspect of the invention, the liquid development of the electrostatic latent image that can reduce the pollution and improve the working environment can be achieved by the above configuration. An apparatus can be provided.
[0081]
According to the seventh aspect of the present invention, in addition to the effect of the first aspect of the invention, there is provided an electrostatic latent image liquid developing device that makes it easy to peel off the toner during transfer. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an electrostatic latent image liquid developing apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic front view of a developing device used in the electrostatic latent image liquid developing device shown in FIG. 1;
3 is a right side view of the developing device shown in FIG. 2. FIG.
4 is a diagram for explaining an operation of a coating unit of the developing device shown in FIG. 2; FIG.
FIG. 5 is a diagram illustrating a method of contacting adjacent rollers of the application unit illustrated in FIG. 4;
6 is a view for explaining the operation of the electrostatic latent image liquid developing apparatus shown in FIG. 1; FIG.
FIG. 7 is a diagram for explaining the entire development process;
FIG. 8 is a diagram showing how an approaching process is performed.
FIG. 9 is a diagram illustrating a toner moving process.
FIG. 10 is a diagram illustrating a separation process of a non-image part.
FIG. 11 is a diagram illustrating a separation process of an image portion.
FIG. 12 is a diagram for explaining the significance of thinning the liquid developer.
FIG. 13 is a diagram illustrating a state in which a developing roller and a photoconductor are in hard contact.
FIG. 14 is a view for explaining soft contact of the electrostatic latent image liquid developing apparatus according to the present embodiment;
15 is a view showing a modification of the contact method of the rollers adjacent to the application section shown in FIG.
FIG. 16 is a partial plan view of the developing belt for explaining unevenness of the liquid developer layer formed on the developing belt.
FIG. 17 is a partial cross-sectional view of the developing belt for explaining the layer thickness of the liquid developer layer formed on the developing belt.
[Explanation of symbols]
10 photoconductor
12a, 12b Unevenness
14a, 14b Liquid developer layer
20 Pre-wet device
30 Charging device
40 Exposure equipment
50 Developer
51 Developer
52 Application part
52a, 52b, 52c, 52d Coating device
60 Transfer device
70 Cleaning device
510 Development Belt
512a, 512b, 612a, 612b, 612c Driving roller
514,616 scraping blade
516 Support roller
520 Bellows pump
522a, 522b, 522c Conveying roller
522d Adjustment roller
524 Separation device
524a arm
526a, 526b, 526c disc wheel
614 Secondary transfer roller
618 Heater

Claims (7)

An electrostatic latent image liquid developing apparatus for developing an electrostatic latent image formed on an image support with toner, which is a charged visualization particle,
A high-viscosity liquid developer of 100 to 10000 mPa · s in which toner is dispersed in a high concentration in an insulating liquid is disposed so as to be at least adjacent to the first roller and the first roller. A coating means for coating on the developer support so as to have a thickness of 5 to 40 μm via a second roller rotating at a peripheral speed faster than the peripheral speed of the first roller provided;
At intervals between the developer support and the image support is smaller than the thickness of the liquid developer layer, and only the developer liquid developer with high viscosity on the support into contact with the image carrier, a latent image of the image support e Bei and a developing means for supplying the liquid developer to the surface,
The first roller is a soft roller having a hardness of 15 to 40 ° (JIS A), and the second roller is a hard roller having a hardness of 90 ° (JIS A) or more. Image liquid developing device. The electrostatic latent image liquid developing device according to claim 1, wherein the second roller rotates at an angular velocity faster than an angular velocity of the first roller. 2. The electrostatic latent image liquid developing device according to claim 1, wherein the outer diameter of the second roller is a non-integer multiple of the outer diameter of the first roller. An electrostatic latent image liquid developing apparatus for developing an electrostatic latent image formed on an image support with toner, which is a charged visualization particle,
Thickness of a high-viscosity liquid developer of 100 to 10,000 mPa · s in which toner is dispersed in a high concentration in an insulating liquid through at least two rollers rotating at a slower peripheral speed as the developer is closer to the developer support. Coating means for coating on the developer support so that the thickness becomes 5 to 40 μm,
At intervals between the developer support and the image support is smaller than the thickness of the liquid developer layer, and only the developer liquid developer with high viscosity on the support into contact with the image carrier, a latent image of the image support e Bei and a developing means for supplying the liquid developer to the surface,
The at least two rollers are characterized in that a hard roller having a hardness of 90 ° (JIS A) or more and a soft roller having a hardness of 15 to 40 ° (JIS A) are alternately contacted and arranged. An electrostatic latent image liquid developing device. The liquid developer has an insulating liquid viscosity of 0.5 to 1000 mPa · s, an electric resistance of 10 ¹² Ωcm or more, a surface tension of 21 dyne / cm or less, and a boiling point of 100 ° C. or more. The liquid developing device for electrostatic latent images according to 1, 2, 3, or 4. 6. The electrostatic latent image liquid developing apparatus according to claim 5, wherein the liquid developer uses silicon oil as an insulating liquid. 7. The electrostatic latent image according to claim 1, wherein the liquid developer contains toner having an average particle diameter of 0.1 to 5 [mu] m at a concentration of 5 to 40%. Liquid developing device.

Images