JPH07271198A - Image forming method and device - Google Patents

Abstract

PURPOSE:To provide an image forming method and device of using a liquid developer of a high concentration and high-viscosity capable of excellently transferring a toner image on an image substrate onto a recording medium. CONSTITUTION:The image forming method for developing an electrostatic latent image formed on a photoreceptor 10 with toner and transferring the toner image onto a paper sheet has a developing process for supplying the liquid developer constituted in such a manner that the toner is dispersed in an insulating liquid applied to a developing belt 510 with a high concentration and having a high viscosity of 100-10000mPa.s to the latent image surface of the photoreceptor 10 to form the toner image thereon, a primary transfer process for primarily transferring the toner image formed on the photoreceptor 10 onto an intermediate transfer belt 602 made of a thin sheet-like material having flexibility and a secondary transfer process for secondarily transferring the toner image primarily transferred onto the intermediate transfer belt 602 to the paper sheet.

Description

Detailed Description of the Invention

[0001]

The present invention relates to electrophotography, electrostatic recording,
The present invention relates to an image forming method and an image forming apparatus in which an electrostatic latent image formed by a method such as ionography is visualized with a liquid developer and then transferred to a recording medium.

[0002]

2. Description of the Related Art Conventionally, an electrostatic latent image formed on an image support is developed with powder toner, which is a charged image-forming particle, and the toner image formed on the image support is recorded on a recording medium. In the image forming method mainly for color transfer to
When the toner image formed on the latent image surface of the image support is transferred to a recording medium such as paper, static electricity is generated by bringing an intermediate transfer member charged with a charge having a polarity opposite to that of the toner into contact with the image support. A method is used in which a toner image is primarily transferred onto an intermediate transfer member by force and then secondarily transferred onto a recording medium. Further, in an image forming apparatus using a liquid developer, when the intermediate transfer method is not used, the surface of the paper is wetted by pre-wetting liquid in order to facilitate transfer of toner to the paper and improve transferability. Is used.

[0003]

By the way, in a conventional large-sized electrostatic recording device, IsoparG which is generally an organic solvent is used.
(Registered trademark: manufactured by Exxon), a low-viscosity liquid developer in which a toner is mixed at a ratio of about 1 to 2% is used. Therefore, the high-concentration and high-viscosity liquid developer (the high-viscosity liquid developer of 100 to 10000 mPa · s in which the toner is dispersed in the insulating liquid at a high concentration) has an increased adhesion to the image support.
When is used, it is not clear what method is suitable for favorably transferring the toner image formed on the latent image surface of the image support to the recording medium. Further, when a liquid developer is used, if the pressing force of the intermediate transfer member against the image support is high, the toner image transferred to the intermediate transfer member is disturbed, which may cause the image transferred to the recording medium to flow. There is a problem. Further, when the surface of the paper is treated with the pre-wet liquid, there is a problem that when the surface roughness of the recording paper changes, a transfer failure occurs when the recording paper is transferred.

[0004]

The present invention has been made in view of the above circumstances, and uses a high-concentration and high-viscosity liquid developer capable of favorably transferring a toner image formed on an image support onto a recording medium. It is an object of the present invention to provide an image forming method and an image forming apparatus which have been described above.

[0005]

In order to achieve the above object, the image forming method of the present invention according to claim 1 uses an electrostatic latent image formed on an image support with charged visualized particles. An image forming method of developing with a toner, and transferring the toner image formed on the image support to a recording medium, comprising:
By supplying a high-viscosity liquid developer of 100 to 10000 mPa · s in which the toner is dispersed in high concentration in the insulating liquid applied on the developer support to the latent image surface of the image support, A developing step of forming a toner image on the image support, a primary transfer step of primary transfer of the toner image formed on the image support onto an intermediate transfer body, and a primary transfer of the toner image onto the intermediate transfer body. And a secondary transfer step of secondary transferring the toner image onto the recording medium.

An image forming method according to a second aspect of the present invention is the image forming method according to the first aspect, wherein at least one of the image support and the intermediate transfer member is formed of a flexible thin plate member. It is characterized by being.

According to a third aspect of the invention, in the image forming method according to the first or second aspect, the toner image formed on the image support is electrostatically applied to the intermediate transfer body in the primary transfer step. It is characterized in that it is primarily transferred on top.

An image forming method according to a fourth aspect of the present invention is the image forming method according to the third aspect, characterized in that the intermediate transfer member has a surface layer having good releasability.

According to a fifth aspect of the present invention, in the image forming method according to the first or second aspect, the intermediate transfer member has an adhesive layer formed on the surface thereof, and the primary transfer step comprises the image supporting step. The toner image formed on the body is primarily transferred onto the intermediate transfer body by the adhesive force of the intermediate transfer body.

An image forming method according to a sixth aspect of the present invention is the image forming method according to the fifth aspect, wherein the adhesive layer of the intermediate transfer member is formed of fluorosilicone rubber.

According to a seventh aspect of the present invention, in the image forming method according to the first, second, third or fourth aspect of the invention, the toner image primarily transferred onto the intermediate transfer member is electrostatically charged in the secondary transfer step. The secondary transfer is performed on the recording medium by force.

An image forming method according to an eighth aspect of the present invention is the image forming method according to the first, second, third, fourth, fifth or sixth aspect, wherein in the secondary transfer step, a secondary transfer member is added to the intermediate transfer member. When the toner image primarily transferred onto the intermediate transfer body is secondarily transferred onto the recording medium by pressing through the recording medium and heating the toner image primarily transferred onto the intermediate transfer body. The feature is that they are fixed at the same time.

An image forming method according to a ninth aspect of the present invention is the image forming method according to the first, second, third, fourth, fifth, sixth, seventh or eighth aspect, in which prior to the developing step, the image support is formed on the image support. It is characterized by comprising a pre-wetting step of applying a pre-wetting liquid which is a dielectric liquid having releasability and chemically inactive.

According to a tenth aspect of the present invention, there is provided an image forming method.
In the invention according to claim 9, the viscosity of the pre-wet liquid is 0.5 to 5 mPa · s, the electric resistance is 10 ¹² Ωcm or more, the boiling point is 100 to 250 ° C, and the surface tension is 21 dyn.
/ Cm or less.

The image forming method according to the invention of claim 11 is
The invention according to claim 10 is characterized in that the pre-wetting liquid contains silicon oil as a main component.

The image forming method according to the invention of claim 12 is
In the inventions according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, the insulating liquid of the liquid developer has a viscosity of 0.5 to 1000 mPa · s and an electric resistance of 10
It is characterized by having a surface tension of ¹² Ωcm or more, a surface tension of 21 dyn / cm or less, and a boiling point of 100 ° C. or more.

According to a thirteenth aspect of the present invention, there is provided an image forming method,
The invention according to claim 12 is characterized in that the liquid developer utilizes silicon oil as an insulating liquid.

According to a fourteenth aspect of the present invention, there is provided an image forming method.
Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1
In the invention described in item 1, 12 or 13, the liquid developer contains a toner having an average particle diameter of 0.1 to 5 μm at a concentration of 5 to 40%.

An image forming apparatus according to a fifteenth aspect of the present invention is
An image forming apparatus for developing an electrostatic latent image formed on an image support with toner, which is a charged image-forming particle, and transferring the toner image formed on the image support to a recording medium. , Toner having a high concentration dispersed in an insulating liquid coated on a developer support, 100 to 10,000 mPa
A developing means for forming a toner image on the image support by supplying a high-viscosity liquid developer of s to the latent image surface of the image support, and a toner formed on the image support. Primary transfer means for primarily transferring the image onto the intermediate transfer member,
Secondary transfer means for secondarily transferring the toner image primarily transferred onto the intermediate transfer member onto a recording medium.

An image forming apparatus according to a sixteenth aspect of the invention is
A fifteenth aspect of the invention is characterized in that at least one of the image support and the intermediate transfer body is formed of a flexible thin plate member.

The image forming apparatus according to the invention of claim 17 is
The invention according to claim 15 or 16, wherein the primary transfer means primarily transfers the toner image formed on the image support onto the intermediate transfer body by electrostatic force. is there.

The image forming apparatus according to the eighteenth aspect of the invention is
The invention according to claim 17 is characterized in that the intermediate transfer member has a surface layer having good releasability.

According to the image forming apparatus of the invention described in Item 19,
The invention according to claim 15 or 16, wherein the intermediate transfer member has an adhesive layer formed on the surface thereof, and the primary transfer means adheres the toner image formed on the image support to the intermediate transfer member. The primary transfer is performed on the intermediate transfer member by force.

An image forming apparatus according to a twentieth aspect of the invention is
The invention according to claim 19 is characterized in that the adhesive layer of the intermediate transfer member is formed of fluorosilicone rubber.

The image forming apparatus according to the twenty-first aspect of the invention is
In the invention according to claim 15, 16, 17 or 18,
It is characterized in that the secondary transfer means secondarily transfers the toner image primarily transferred onto the intermediate transfer member onto the recording medium by electrostatic force.

The image forming apparatus according to the twenty-second aspect of the present invention is
The invention according to claim 15, 16, 17, 18, 19 or 20, wherein the secondary transfer means presses the secondary transfer member against the intermediate transfer member via the recording medium, and By heating the toner image primarily transferred onto the intermediate transfer member, the toner image primarily transferred onto the intermediate transfer member is secondarily transferred onto the recording medium and fixed at the same time.

The image forming apparatus according to the twenty-third aspect of the present invention is
The invention of any one of claims 15, 16, 17, 18, 19, 20, 21 or 22, wherein a pre-wet liquid, which is a dielectric liquid having releasability and chemically inert, is provided on the image support. It is characterized by comprising a pre-wetting step of applying.

[0028]

According to the image forming method of the present invention, since the liquid developer in which the toner is dispersed at a high concentration is made into a thin layer and developed, the liquid amount is far larger than that of the conventional low concentration liquid developer. Can be reduced to The liquid developer has a viscosity of 100.
When it is more than 00 mPa · s, it becomes difficult to stir the insulating liquid and the toner, and there is a problem how to make the liquid developer. Therefore, a liquid developer of 10,000 mPa · s or more becomes unrealistic in terms of cost and becomes unrealistic. On the other hand, at 100 mPa · s or less, the toner density becomes low and the dispersibility of the toner becomes poor.
The developer cannot be developed in a thin layer for development. The layer thickness of the liquid developer needs to be thin when the toner concentration is high and thick when the toner concentration is low. In addition, the higher the viscosity, the thinner it needs to be. However, when the layer thickness is thicker than 40 μm, excessive adhesion of toner occurs and image noise occurs. On the other hand, when the layer thickness is less than 5 μm, unevenness occurs when a solid black image is output. Further, since the intermediate transfer member is used, the toner image formed on the image support is not directly transferred to the recording medium such as paper. When a high-concentration and high-viscosity liquid developer is used, if the surface of the recording medium is rough, the toner image transferred onto the recording medium may have image defects. Therefore, it is preferable to apply a certain pressing force when transferring the toner image to the recording medium. However, when a photoreceptor is used as the image support and the toner image formed on the photoreceptor is directly transferred to the recording medium, sufficient pressure cannot be applied to the photoreceptor. In the present invention, after the toner image formed on the image support is primarily transferred onto the intermediate transfer member, the toner image primarily transferred onto the intermediate transfer member is secondarily transferred onto the recording medium. In this case, sufficient pressing force can be applied. Therefore, according to the present invention, the toner image primarily transferred onto the intermediate transfer member can be satisfactorily secondarily transferred onto the recording medium such as paper without causing image loss.

In the image forming method according to the second aspect, at least one of the image support and the intermediate transfer member is formed of a flexible thin plate member, so that it is formed on the latent image surface of the image support. Since it is possible to disperse the contact pressure when the toner image and the intermediate transfer member come into contact with each other, it is possible to prevent the toner image primarily transferred on the intermediate transfer member from being crushed and disturbed. The toner image formed on the support can be transferred onto the recording medium without causing image deletion.

According to the image forming method of the third aspect, the so-called electrostatic transfer utilizing the electrostatic force is used in the primary transfer step, so that the same operation as that of the first aspect of the invention is achieved.

In the image forming method according to the fourth aspect, since the surface layer of the intermediate transfer member has a good releasability, the releasability between the intermediate transfer member and the toner is improved, so that the image is formed on the intermediate transfer member. The primary-transferred toner image can be satisfactorily secondary-transferred to the recording medium.

In the image forming method according to claim 5, an adhesive layer is formed on the surface of the intermediate transfer member, and the toner image formed on the image support is primarily transferred onto the intermediate transfer member by the adhesive force of the intermediate transfer member. By transferring, the toner image formed on the image support can be transferred onto the recording medium without using electrostatic force. As a result, it is not necessary to wet the surface of the recording medium with the pre-wet liquid for processing, and therefore, the toner image formed on the image support regardless of the surface roughness of the recording paper of the recording medium or the water absorption of the pre-wet liquid. Can be satisfactorily transferred onto the recording medium. Further, since it is not necessary to charge the intermediate transfer member by corona discharge, ozone is not generated during the primary transfer.

In the image forming method according to the sixth aspect, since the adhesive layer of the intermediate transfer member is formed of fluorosilicone rubber, the fluorosilicone rubber improves the releasability from the toner by heating, so the intermediate transfer member is improved. The toner image primarily transferred onto the recording medium can be favorably secondarily transferred onto the recording medium without using electrostatic force.

In the image forming method according to the seventh aspect, the so-called electrostatic transfer utilizing the electrostatic force is used in the secondary transfer step, so that the same operation as the invention according to the first aspect is achieved.

According to the image forming method of claim 8, the toner image primary-transferred onto the intermediate transfer member is pressed onto the recording medium and the intermediate transfer member is pressed against the intermediate transfer member without using electrostatic force. It is not necessary to wet the surface of the recording medium with the pre-wetting liquid because the toner image that has been primarily transferred onto the transfer member is secondarily transferred and fixed at the same time by utilizing the heating.
As a result, the secondary transfer can be favorably performed regardless of the surface roughness of the recording paper of the recording medium and the water absorption of the pre-wetting liquid. In addition, the transfer device and the fixing device can be integrated, so that the size of the device can be reduced.

In the image forming method of the present invention, the pre-wetting liquid, which is a dielectric liquid having releasability and chemically inert, is applied onto the image support prior to the developing step. By including the pre-wetting step, it is possible to prevent the toner from adhering to the non-image portion on the image support during the developing step. By using the intermediate transfer member, when electrostatic transfer is used for the primary transfer,
It is not necessary to smooth the surface of the recording medium such as paper in order to facilitate the transfer of the toner on the image support to the intermediate transfer body. Therefore, if the intermediate transfer member does not absorb the pre-wetting liquid and the surface is smooth,
A small amount of pre-wetting liquid is sufficient for the primary transfer. As a result, the toner image formed on the image support can be primary-transferred onto the intermediate transfer member without selecting the type of recording medium, and the pre-wetting liquid at the time of primary transfer can be reduced. That is, the amount of pre-wet liquid has come to be determined by the amount required for development.

According to the tenth aspect of the image forming method, since the pre-wetting liquid has the above-mentioned characteristics, a pre-wetting liquid having releasability and good insulation can be obtained. In the present invention, since there is no action of absorbing the pre-wetting liquid of the intermediate transfer member, a small amount of the pre-wetting liquid in the primary transfer is sufficient. However, a small amount of the pre-wetting liquid that has adhered to the intermediate transfer member during the primary transfer is absorbed by the paper or the like during the secondary transfer, so it is necessary to evaporate it during fixing. Therefore, the viscosity is 0.5 to 5 in order to easily evaporate.
mPa · s is desirable. When the viscosity is 5 mPa · s or more, it becomes difficult to evaporate, and when the viscosity is 0.5 mPa · s or less, the volatility becomes high, which is not suitable because it is subject to legal regulation as a dangerous substance. When the boiling point is 100 ° C. or less, the amount of evaporation increases, which causes a problem in the method of storing the pre-wet liquid, the entire device must be hermetically sealed, and it is difficult to improve the working environment. On the other hand, the boiling point is 250
If the temperature is above ° C, the paper curls during fixing and cannot be used, and high energy is required for heating, resulting in high cost. When the electric resistance is 10 ¹² Ωcm or less, the insulating property is deteriorated and the prewetting liquid cannot be used. Therefore, it is desirable that the electric resistance value is as high as possible. When the surface tension is 21 dyn / cm or more, the wettability becomes poor and the compatibility with the liquid developer becomes poor. Therefore, it is desirable that the surface tension be as low as possible.

In the image forming method according to the eleventh aspect, since the pre-wetting liquid contains silicon oil as a main component, the pre-wetting liquid having the characteristics according to the ninth aspect can be obtained.

According to the twelfth aspect of the image forming method, by using an insulating liquid having the above characteristics, a high-viscosity liquid developer can be obtained. Since the liquid developer on the developer support is formed in a thin layer, the amount of insulating liquid contained in the liquid developer layer is extremely small. The insulating liquid contained in is very small. Therefore, the amount of insulating liquid absorbed by paper or the like during transfer is extremely small, but the viscosity is 1
Since it is 000 mPa · s or less, there is no particular problem of adhesion of the insulating liquid to paper or the like. Also, the viscosity is 0.5 mP
Since it is more than a · s, the volatility is not high enough to be regulated as a dangerous substance. Since the insulating liquid has a boiling point of 100 ° C. or higher, there is no problem in the method of storing the developer, and it is not necessary to make the entire apparatus a closed structure. Also, the working environment does not deteriorate.
Since the electric resistance is 10 ¹² Ωcm or more, there is no problem of toner conductivity and it can be sufficiently used as a developer. Since the surface tension is 21 dyn / cm or less, the wettability is good and the compatibility with the pre-wet liquid is good.

In the image forming method according to the thirteenth aspect, since the insulating liquid mainly contains silicone oil, the insulating liquid having the characteristics according to the twelfth aspect can be obtained.

In the image forming method according to the fourteenth aspect, since the liquid developer contains the toner having the average particle diameter of 0.1 to 5 μm in the concentration of 5 to 40%, the toner is highly concentrated in the insulating liquid. A dispersed liquid developer can be obtained. In addition, the resolution is improved in almost inverse proportion to the particle size of the toner. Usually, the toner is present as a mass of about 5 to 10 particles on the printed paper, and therefore, when the average particle diameter of the toner is 5 μm or more, the resolution becomes poor. On the other hand, when the average particle diameter of the toner is 0.1 μm or less, the physical adhesive strength increases, and it becomes difficult to remove the toner during transfer.

The operation of the image forming apparatus according to the fifteenth to twenty-third aspects is the same as that of the invention according to the first to ninth aspects.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 is a schematic configuration diagram of a color-compatible image forming apparatus according to a first embodiment of the present invention, FIG. 2 is a schematic perspective view of a pre-wetting apparatus used in the image forming apparatus shown in FIG. 1, and FIG. 4 is a diagram for explaining the operation of the image forming apparatus shown in FIG. 4, FIG. 4 is a diagram for explaining the operation of the prewetting apparatus shown in FIG. 2, and FIG. 5 is a diagram when the prewetting liquid supply member is brought into contact with the photoconductor. It is a figure showing the flow of the pre-wet liquid.

As shown in FIG. 1, a color-compatible image forming apparatus 1 according to the first embodiment of the present invention includes a photoconductor 10 which is an image support, and a pre-wetting liquid which is applied onto the photoconductor 10. Wetting device 20, charging device 30 that charges photoconductor 10, and exposure device 4 that exposes an image on photoconductor 10.
0 and a developing device 5 that visualizes the electrostatic latent image by supplying toner to the portion of the photoconductor 10 where the electrostatic latent image is formed.
0, a transfer device 60 for transferring the toner on the photoconductor 10 to a predetermined paper, a paper feeding device 610 for conveying the predetermined paper to the transfer device 60, and fixing the toner transferred to the paper by the transfer device 60. The fixing device 620 includes a cleaning device 70 that removes the toner remaining on the photoconductor 10, and a neutralization device 80 that neutralizes the charged photoconductor 10.

For the charging device 30, the exposure device 40, the paper feeding device 610, the fixing device 620, the cleaning device 70, and the neutralization device 80, the conventional techniques used in conventional electrophotographic printers are used in most cases. be able to. Therefore, in the first embodiment, the description of each of the above devices is omitted, and the prewetting device 20, the developing device 50, and the transfer device 60, which are the main parts of the present invention, will be described.

As shown in FIG. 2, the pre-wetting device 20 of the first embodiment includes a plate-like pre-wetting liquid supply body 202 having a length substantially the same as the image width drawn on the photoconductor 10.
Case 204 for storing the pre-wet liquid supply body 202
And a tank 206 for storing the pre-wet liquid 220,
A pump 208 for pumping the pre-wet liquid 220 stored in the tank 206, and tubes 210a and 210b
And a displacement device 212.

As the pre-wet liquid supply body 202, a continuous porous body having a three-dimensional network structure in which pores are continuous, for example, Belleater (registered trademark: Kanebo Co., Ltd.) is used.
The bell eater is pre-wet liquid 220 for the volume of the pores.
When the pre-wet liquid 220 exceeding the pore volume is supplied, the pre-wet liquid 220 can be uniformly discharged in the direction perpendicular to the flow direction of the pre-wet liquid 220. Case 20
As shown in FIG. 4, on the surface of No. 4 facing the photoconductor 10,
An opening 204a is provided so that the bottom surface of the pre-wet liquid supply body 202 can be brought into contact with the photoconductor 10. The tube 210 a conveys the pre-wet liquid 220 pumped up by the pump 208 to the supply side 202 a of the pre-wet liquid supply body 202. A space portion 204b is formed between the supply side 202a of the pre-wet liquid supply member 202 and the case 204. The pre-wet liquid 220 is stored in the space portion 204b and then supplied to the supply side 2.
It is supplied from 02a. The tube 210b conveys the pre-wet liquid 220 discharged from the discharge side 202b of the pre-wet liquid supply body 202 to the tank 206. When a signal from the outside is not input, the displacement device 212, as shown in FIG.
02 is held at a position away from the photoconductor 10, and when a signal from the outside is input, the pre-wet liquid supply body 202 is brought into contact with the photoconductor 10 as shown in FIG. 4B.

The developing device 50 of the first embodiment drives the developing belt 510, which is a developer support, and rotationally drives the developing belt 510 and holds the developing belt 510 so that a part of the developing belt 510 abuts on the photoconductor 10. Rollers 512a and 512
b, 512c, a developer supply device 51, and a scraping blade (not shown) for scraping off the developer adhering to the developing belt 510 after development.

The developer supply device 51 is constituted by four developing cartridges 51a, 51b, 51c, 51d (hereinafter also simply referred to as developing cartridges) fixed to a rotary shaft 509. Each developing cartridge includes a tank 502,
Discharge roller 502a provided at the discharge port of tank 502
And a supply roller 504 provided so as to contact the discharge roller 502a and an application roller 506 provided so as to contact the supply roller 504. Liquid developer 508a containing yellow toner is stored in the tank 502 of the developing cartridge 51a, and liquid developer 508 containing magenta toner is stored in the tank 502 of the developing cartridge 51b.
b, the liquid developer 508c containing cyan toner is stored in the tank 502 of the developing cartridge 51c, and the liquid developer 508d containing black toner is stored in the tank 502 of the developing cartridge 51d. Liquid developer 508a, 508b, 508c, 5
08d is also simply referred to as liquid developer 508).

The discharge roller 502a is the supply roller 504.
By rotating in the direction opposite to that of
Liquid developer 508 stored in the No. 02 supply roller 504
Transport to. The supply roller 504 rotates in a direction opposite to the rotation direction of the coating roller 506 to convey the liquid developer 508 supplied by the discharge roller 502a to the surface of the coating roller 506. The coating roller 506 rotates in a direction opposite to the rotation direction of the developing belt 510 to coat the surface of the developing belt 510 with the liquid developer 508 supplied by the supply roller 504. Development belt 5
The supply roller 504 and the application roller 506 were used to supply the liquid developer 508 to the liquid developer 508 in the first embodiment, as described below, using the liquid developer 508 in which the toner was dispersed in a high concentration. Therefore, a small amount of developer is applied to the developing belt 5.
This is because it is necessary to apply it thinly and uniformly on the surface of 10. It should be noted that one or a plurality of transport rollers that transport the liquid developer 508 may be provided between the supply roller 504 and the application roller 506. In this case, the liquid developer can be applied onto the developing belt 510 more uniformly.

In the developer supply device 51 having the above-described structure, the rotation shaft 509 is rotated to bring the application roller 506 included in one of the developing cartridges into contact with the developing belt 510, so that the developing belt 510 has a desired color toner. A liquid developer 508 containing is applied.

The developing belt 510 includes a driving roller 512.
The liquid developer 508 applied to the surface of the photoconductor 10 by the application roller 506 by being rotated in the direction opposite to the rotation direction of the photoconductor 10 by a, 512b, 512c.
To transport. As the developing belt 510, a flexible member such as a seamless metal belt such as a nickel belt or a resin belt such as a polyimide belt is used. As a result, the tension of the developing belt 510 is adjusted and the liquid developer layer formed on the developing belt 510 and the photosensitive member 1 are formed.
When the contact pressure at the time of contact with the pre-wet liquid layer formed on 0 is dispersed, the photoconductor 10 and the developing belt 510
A space is formed between and. Therefore, in the developing process, the liquid developer layer formed on the developing belt 510 and the pre-wet liquid layer formed on the photoconductor 10 are brought into contact with each other while maintaining a two-layer state, and both are pre-wet liquid. It can be separated inside the layers. Incidentally, the developing belt 510
Must be capable of applying an electrical development bias. Therefore, when a resin belt is used, it is necessary to reduce the electric resistance value by conducting conductive processing on the surface of the belt or adding conductive fine particles to the material of the belt. When the belt itself has conductivity, the driving roller 5
As the rollers 12a, 512b, 512c, rubber rollers having a low electric resistance value to which conductive fine particles are added so that a developing bias can be applied are used. If the surface of the belt has been subjected to electro-conductivity, place a conductor that contacts the surface of the belt,
A developing bias is applied to this conductor.

The transfer device 60 of the first embodiment includes an intermediate transfer belt 602 which is an intermediate transfer member, and an intermediate transfer belt 602.
Rollers 604a, 604b, 604 for rotating and driving
c and holding rollers 605a and 605 for holding a part of the intermediate transfer belt 602 so as to abut on the photoconductor 10.
b, a corona discharger 606 that charges the intermediate transfer belt 602 with a charge having a polarity opposite to that of the toner, and a secondary transfer roller 603 that is a secondary transfer member that is provided so as to be separable from the intermediate transfer belt 602. A power supply device 609 that applies a bias voltage to the secondary transfer roller 603 to charge the secondary transfer roller 603 with an electric charge having a polarity opposite to that of the toner.
And a power supply device 609 for applying a bias voltage to the driving roller 604a and the holding roller 605b in order to charge the intermediate transfer belt 602 with an electric charge having a polarity opposite to that of the toner.
a. The power supply device 609a applies a voltage to the driving roller 604a and the holding roller 605b during the primary transfer, and sets the driving roller 604a and the holding roller 605b to the ground potential during the secondary transfer. Therefore, an electric field is generated between the intermediate transfer belt 602 at the ground potential and the secondary transfer roller 603 charged with an electric charge having a polarity opposite to that of the toner, and the secondary transfer is performed by this electric field.

The intermediate transfer belt 602 includes a driving roller 60.
4a, 604b, 604c rotate the photoreceptor 10 in a direction opposite to the rotation direction. The intermediate transfer belt 602 has
A flexible belt member such as a metal belt such as a seamless nickel belt, a resin belt such as a polyimide film belt or a PTE film belt, or a rubber belt is used. As a result, the contact pressure when the toner image formed on the photoconductor 10 and the intermediate transfer belt 602 come into contact with each other can be dispersed. The intermediate transfer belt 6
02 must be capable of being charged.
Therefore, when a resin belt is used, it is necessary to subject the surface of the belt to conductive treatment or to add conductive fine particles to the material of the belt. As will be described later, in the case of this embodiment in which both primary transfer and secondary transfer are performed by electrostatic transfer, the electric resistance value of the intermediate transfer belt 602 is 10 ³ to 10 ¹² Ωcm, and when the bias voltage is applied to perform the primary transfer. 10 ⁶ to 10 ⁸ Ωc
m, 10 ⁸ to 1 for primary transfer using corona discharge
It is preferably 0 ¹⁰ Ωcm.

On the intermediate transfer belt 602, a surface layer of Teflon, silicon or the like having a good releasing property is formed. This is to weaken the physical adhesion of the toner to the transfer belt 602 and facilitate the movement of the toner to the paper.

The secondary transfer roller 603 rotates in a direction opposite to the rotation direction of the intermediate transfer belt 602, so that the paper conveyed by the paper feeding device 610 is transferred to the intermediate transfer belt 6 by the secondary transfer roller 603.
02 and the secondary transfer roller 603. The secondary transfer roller 603 must be able to apply a bias voltage. Therefore, for the secondary transfer roller 603, a member having conductivity such as metal or conductive rubber is used.

The surface of the secondary transfer roller 603 is coated with fluorine. This is because by improving the releasability from the toner, the toner adhering to the secondary transfer roller 603 can be easily removed and the secondary transfer roller 603 can be prevented from being soiled.

Next, the image forming material used in the first embodiment of the present invention will be described. The liquid developer 508 used in the first embodiment is a resin serving as a binder such as epoxy,
A toner is composed of a charge control agent that gives a predetermined charge to the toner, a color pigment, a dispersant that uniformly disperses the toner, and the like, and a carrier liquid. The toner composition is basically similar to that used in conventional liquid developers, but their formulation has been modified to be compatible with silicone oils for adjusting charging characteristics and dispersibility. The smaller the average particle size of the toner is, the better the resolution is. However, the smaller the particle size is, the larger the physical adhesive force is, and the more difficult it is to remove when transferring. For this reason, in the first embodiment, the average particle diameter of the toner is adjusted so that the center is around 2 to 4 μm for the purpose of improving transferability.

The viscosity of the liquid developer depends on the carrier liquid used,
It depends on the resin, color pigment, charge control agent, etc. and their concentrations. In the first embodiment, the viscosity is 50-6000.
The experiment was performed by changing the mPa · s and the toner concentration in the range of 5 to 40%.

As the carrier liquid, one having a low viscosity such as dimethylpolysiloxane oil having a high electric resistance or cyclic polydimethylsiloxane oil is used. Incidentally, the developing belt 510
Since the liquid developer layer formed on top is formed in a thin layer, the carrier liquid contained in the liquid developer layer is extremely small, so that the amount of carrier liquid in the liquid developer supplied to the latent image surface of the photoconductor 10 is small. The carrier liquid contained in is very small. Therefore, the carrier liquid absorbed in the paper or the like during transfer is extremely small, and if the viscosity is 1000 mPa · s or less, almost no carrier liquid remains after fixing. According to experiments conducted by the present inventors, the carrier liquid has a viscosity of 2.5 mPa · s, DC3 manufactured by Dow Corning Co., USA.
44 and a viscosity of 6.5 mPa · s, when the image output experiment was conducted using DC345 of Dow Corning Co., USA,
In each case, no carrier liquid remained on the paper after fixing. However, since the volatility is high, it is necessary to make the developing device have a closed structure. Furthermore, the carrier liquid has a viscosity of 2
Shin-Etsu Silicon KF-96-20 with 0 mPa · s
No carrier liquid remained on the paper after fixing was observed when the image output experiment was carried out using. Further, since the volatility is not so high, it is not necessary to make the developing device have a closed structure. DC344, DC345 and KF-96-
20 is generally used in cosmetics and has high safety such as toxicity. There are many kinds of carrier liquids such as KF9937 manufactured by Shin-Etsu Silicon Co., Ltd., and any one may be selected as long as the electric resistance, the evaporation property, the surface tension, the safety and the like are satisfied.

Further, in experiments conducted by the inventors, when the surface tension is large, fogging or toner lumps may adhere, and experimentally, when the surface tension is 21 dyn / cm or more, a problem in image quality occurs. I found it easy.

The electric resistance value is preferably 10 ¹⁴ Ωcm or more because of the problem of toner charging stability. At least 1
0 ¹² Ωcm or more is necessary. In the description of the first embodiment,
In view of these experimental results, DC is inexpensive and easily available.
An example using 345 is shown.

The pre-wetting liquid easily evaporates during fixing without disturbing the electrostatic latent image formed on the image support,
It is required that fogging and lumps of toner do not adhere. As an example, DC34 manufactured by Dow Corning, USA
4, DC200-0.65, -1.0, -2.0, KF96L-1, KF9937 manufactured by Shin-Etsu Silicon Co., and the like. Generally, it is necessary to select a highly evaporative silicone oil.

In an experiment conducted by the inventors, the liquid viscosity was 0.
The liquid was dried by development, transfer, and fixing without problems in the range of 5 to 3 mPa · s, but from 5 mPa · s to 6 mPa · s
-At about s, there was a tendency that time and temperature were required for drying the liquid at the time of fixing. If it is 10 mPa · s, the energy required for drying becomes too large, which is not general. Also,
If it is 0.5 mPa · s or less, the volatility increases, so
Not suitable because it is subject to legal regulation as a dangerous goods. Also,
The boiling point is required to be 250 ° C. or lower due to the effect of heating the paper.

The surface tension should be as low as possible in order to eliminate the adhesive force between the developer and the image support, improve the releasability and prevent the image from becoming dirty and fogging, and improving the image resolution and fogging. Good. According to the experiments by the present inventors, 2
The limit is about 0 to 21 dyn / cm, and it is necessary to select one lower than this.

When the electric resistance is low, the latent image charge leaks to blur the image. Therefore, it is necessary to use the highest possible one. Experimentally, about 10 ¹⁴ Ωcm or more is desirable. A minimum of 10 ¹² Ωcm is required.

Next, the operation of the image forming apparatus according to the first embodiment of the present invention will be described. First, as shown in FIG. 3A, the surface of the photoconductor 10 is charged by the charging device 30. Generally, a corona discharger is used for the charging device 30. Next, the 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 photoconductor 10. As shown in FIG. 3B, the portion of the laser scanner exposed to the light becomes conductive, so that the charge disappears, and the portion not exposed to the light remains as an electrostatic latent image which is an image of the charge.

Next, as shown in FIG. 3C, the above-mentioned pre-wetting liquid 220 is applied onto the photoconductor 10 by the pre-wetting device 20. The pre-wetting device 20 receives the pre-wetting liquid supply body 202 when a signal from the outside is input.
Is brought into contact with the photoconductor 10. Pre-wet liquid supply body 20
In the inside of 2, the prewetting liquid 22 is provided by the pump 208.
0 is constantly circulated, and the pre-wet liquid 2 that exceeds the volume of the pores of the bell eater, which is the pre-wet liquid supply body 202.
As shown in FIG. 5, 20 is a pre-wet liquid supply body 20.
It is discharged from the second discharge side 202b and is discharged from the bottom surface of the pre-wet liquid supply body 202, and is evenly applied on the photoconductor 10 without damaging the photoconductor 10.

Then, the developing device 50 visualizes the electrostatic latent image. The liquid developer 50 discharged from the tank 502 by the discharge roller 502a and supplied to the supply roller 504.
After being conveyed to the coating roller 506, the developing belt 8
10 is applied. By rotating the developing cartridge 51, a liquid developer containing any one of yellow, magenta, cyan, and black toners can be applied to the developing belt 510. The liquid developer 508 applied to the developing belt 510 forms a thin layer on the developing belt 510 with its layer thickness adjusted by a regulating means such as a blade or a roller. The liquid developer layer thus formed on the developing belt 510 is formed on the photoreceptor 1 as shown in FIG.
The electrostatic latent image is brought close to the electrostatic latent image formed on the surface of No. 0, and the electrostatically-charged toner moves the charged toner onto the photoconductor 10 to form a toner image.

Next, the toner image formed on the photoconductor 10 by the transfer device 60 is primarily transferred onto the intermediate transfer belt 602 which is an intermediate transfer member. As shown in FIG. 3 (E), the toner image formed on the photoconductor 10 is the bias voltage applied by the toner image formed on the photoconductor 10 by the corona discharger 606 or by the power supply device 609a. Thus, the electrostatic force generated between the toner and the transfer belt 602 charged with an electric charge having the opposite polarity causes the toner to move and be transferred onto the intermediate transfer belt 602. On the other hand, photoconductor 1
In the case of 0, the liquid developer 508 remaining on the photoconductor 10 is removed by the cleaning device 70, and then the static eliminator 8 is removed.
The charge is removed by 0. Then, the developing cartridge 51 rotates, and the above cycle from the charging to the discharging is repeated again, so that yellow on the intermediate transfer belt 602,
The magenta, cyan, and black toner images are transferred one on top of the other. As a result, a toner image corresponding to colorization is formed on the transfer belt 602.

Next, the transfer device 60 secondarily transfers the toner image corresponding to color formed on the intermediate transfer belt 602 to the paper as a recording medium. Intermediate transfer belt 602
The color toner image formed on the upper side of FIG.
As shown in (F), the bias voltage applied to the secondary transfer roller 603 by the power supply device 609 and the power supply device 60.
Due to an electric field generated between the intermediate transfer belt 602 and the intermediate transfer belt 602 grounded by 9a, the sheet is moved and transferred onto the sheet conveyed by the sheet feeding device 610 and fed between the intermediate transfer belt 602 and the secondary transfer roller 603. And FIG.
As shown in (G), the fixing roller 62 of the fixing device 620.
The transferred toner is thermally melted and fixed by the fixing heater 624 provided in the second unit. Thereby, a color image can be formed on the paper.

6 to 10 are views for explaining the developing process of the first embodiment of the present invention in detail, FIG. 6 is a diagram for explaining the developing process as a whole, and FIG. 7 is a drawing for showing the approaching process. FIG. 8 is a diagram showing a state of the toner movement process, FIG. 8 is a diagram showing a state of the toner movement process, FIG. 9 is a diagram showing a separation process of the non-image portion, and FIG. 10 is a diagram showing a separation process of the image portion. Unlike the conventional developing process, in the developing process of the first embodiment, as shown in FIG. 6, the developing belt approaches the photoconductor and the liquid developer approaches the photoconductor surface, and the liquid developer layer. And a prewetting liquid layer are in soft contact with each other to move the toner, and a separation process in which the developing belt is separated from the photoconductor and separated into toner adhering to the developing belt and toner adhering to the photoconductor. It is thought to consist of three processes.

In the approaching process, the developing belt 510 is made of a flexible member as shown in FIG.
A small gap, that is, a space d is formed between the developing belt 510 and the photoconductor 10, and the high-viscosity liquid developer including the carrier liquid and the toner is soft-contacted with the pre-wet liquid. As a result, the pre-wet liquid having a low viscosity is slightly pushed back and forth, and a liquid pool of the pre-wet liquid is generated.

In the toner moving process, as shown in FIG. 8, in the image portion, the toner passes through the pre-wet liquid layer mainly due to the Coulomb force due to the electric field formed between the charges on the photoconductor 10 and the developing belt 510. And move to the latent image surface. On the other hand, the toner in the non-image area is basically the photosensitive member 10.
Since the surface of the liquid developer and the liquid developer layer are separated by the pre-wet liquid layer, unnecessary toner does not adhere to the surface of the photoconductor 10.

In the separation process, in the non-image part, as shown in FIG.
Basically, the liquid developer remains on the developing belt 510 as shown in FIG. At the interface between the pre-wet liquid layer and the liquid developer layer, when the two layers are separated, 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 area, as shown in FIG. 10, the toner that has moved to the surface of the photoconductor 10 displaces the pre-wet liquid layer, so that the pre-wet liquid layer is located on the toner layer and is separated in that layer. On the developing belt 510, a part of the carrier liquid and a part of the pre-wetting liquid remaining after the toner moves form a layer. The pre-wetting liquid remaining on the photoconductor 10 facilitates the movement of the toner due to the electrostatic force in the subsequent transfer process.

FIG. 11 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 liquid developer 508
Since the viscosity of the toner is high, the toner group that tries to move from the developing belt 510 to the surface of the photoconductor 10 by the electrostatic force forms a cluster with respect to the toner located around the toner group and does not cut off the viscosity. Since it moves to the surface of the toner, excessive adhesion of toner occurs and image noise occurs. In order to suppress the generation of these clusters, it is necessary to control the thickness of the liquid developer layer to a minimum value at which development can be sufficiently performed.

FIG. 12 is a diagram showing a state in which the developing roller, which is the developing support, and the photosensitive member are in hard contact, and FIG. 13 is a diagram for explaining the soft contact of the first embodiment. As explained above, in the developing process of the first embodiment, the function of the pre-wet liquid layer for image formation is important. Therefore, an important requirement in the developing process is to maintain the two-layer state of the pre-wet liquid layer and the liquid developer layer. As shown in FIG. 12, when the developing roller and the photoconductor are in hard contact, the two-layer state cannot be maintained. In the first embodiment, as shown in FIG. 13, by using the developing belt 510 composed of a flexible member as the developer support, the developing belt 5
By adjusting the tension of 10 to disperse the contact pressure when the liquid developer layer formed on the developing belt 510 and the pre-wet liquid layer formed on the photoconductor 10 are dispersed,
A minute gap, that is, a gap d is formed between the photoconductor 10 and the developing belt 510. Therefore, in the developing process, the liquid developer layer and the pre-wet liquid layer can be brought into contact with each other while maintaining the two-layer state.

Next, optimization of the layer thickness of the liquid developer layer, the layer thickness of the pre-wet liquid layer, and the development gap, that is, the gap will be described. The layer thickness of the liquid developer layer is particularly 500 mP when the viscosity of the liquid developer is 50 mPa · s or more.
It is necessary to reduce the thickness of a or more. Ideally, it should be slightly thicker than the layer thickness that satisfies the toner development amount (that is, the density when solid black is produced) required at the time of development. This is because when a high-viscosity liquid developer is used, electrostatically selected toner moves to the photoconductor along with excess toner due to the viscosity of the liquid, which causes abnormal toner adhesion. This is because the image is smeared and the image is stained. In an experiment conducted by the inventors, a good image was obtained with a layer thickness of about 5 μm for a liquid developer having a high toner concentration and about 40 μm for a liquid developer having a low toner concentration. When a liquid developer having a toner concentration of 20 to 30% was used, good image quality was obtained when the layer thickness of the liquid developer was about 8 to 20 μm.

The layer thickness of the pre-wet liquid layer has an optimum value depending on the viscosity and surface tension of the selected pre-wet liquid. If it is too thin, the high-viscosity liquid developer irregularly adheres to the photoconductor to cause image contamination. As the amount of pre-wetting liquid is increased, image stains are improved,
The optimum value is confirmed. When the amount is further increased, the charge of the latent image flows, the sharpness and the resolution are deteriorated, and the toner flows during development, which also tends to blur the image. D
In experiments using C344, 30 μm or less, especially 20 μm
Good results were obtained with a thickness of m or less. For those having a lower viscosity than this, good results can be obtained with a thinner thickness or a thicker thickness. However, for high viscosity ones, the optimum value tends to have a narrow range.

As in the case of the conventional developing method, the narrower the gap between the photosensitive member and the developing belt, that is, the interval, the better the resolution and the uniformity of the density of the solid portion in the image quality. The highly viscous liquid developer used in the first embodiment has a strong cohesive force between the toners, so that the toner released from the developer support or carrier particles by mechanical impact or electrostatic force is developed like the powder developer. There is no phenomenon like that used in. That is, development is not performed with an air layer interposed between the liquid developer layer and the photoconductor. Therefore, it is essential that the developing belt is in contact with the liquid developer layer, the liquid developer layer is in contact with the pre-wet liquid layer, and the pre-wet liquid layer is in contact with the photosensitive member. Therefore, the development gap, i.e., the distance d, must be a dimension that is equal to or less than the thickness of the liquid developer layer and the prewetting liquid layer and does not disturb the respective layers. In the first embodiment, when the pre-wet liquid layer on the photoconductor 10 and the liquid developer layer on the developing belt 510 are brought into contact with each other in accordance with the difference in viscosity and toner concentration of the liquid developer, the gap is from 8 μm. Development belt 5 so that it is between 50 μm
The tension of 10 was adjusted.

Table 1 shows the results of the experiment for image formation under the above-mentioned conditions. From these results, the optimum range of the developer and the viscosity of the pre-wet liquid for the developing method of the first embodiment is 100 mPa · s to 6000 mPa · s for the developer.
s, pre-wetting liquid is 0.5 mPa · s to 5 mPa · s
It was found to be between s. Regarding image quality,
The thickness varies depending on the thickness of the liquid developer layer on the developing belt, the thickness of the pre-wet liquid layer, the developing gap, that is, the gap, etc. It was confirmed that the optimum area of the liquid developer falls within the range shown in Table 1. The silicone oil of the pre-wet liquid is DC200 series manufactured by Dow Corning, and the carrier liquid of the developing liquid is DC of the same company.
345 was used.

[0082]

[Table 1]

According to the first embodiment of the present invention, the use of silicone oil as the carrier liquid for the liquid developer has the following advantages over the conventional ones.

Conventional liquid developers generally use IsoparG (registered trademark: manufactured by Exxon) as a carrier liquid.
Since this Isopar has a resistance value not as high as that of silicone oil, when the toner concentration is increased, that is, when the distance between particles is reduced, the chargeability of the toner is deteriorated. Therefore, Isop
In the case of ar, the toner density is limited. On the contrary,
Since the silicone oil used in the first embodiment has a sufficiently large resistance value, the toner concentration can be increased. Further, generally, in the case of Isopar, the toner dispersion state is good, and therefore even if the toner concentration is 1 to 2%, the toner particles repel each other, so that the toner particles are uniformly dispersed. On the other hand, when the toner concentration is 1 to 2%, the silicone oil has poor dispersibility and will be precipitated soon. However, when the toner concentration is set to 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 high density is used. As a result, compared to the conventional low-concentration liquid developer, the amount of developer can be significantly reduced,
It is possible to reduce the size of the device. 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 or powder developer.

Isopar used in the conventional liquid developer is
As mentioned above, it is highly volatile and emits a foul odor,
There is a problem that it not only deteriorates the work environment but also causes pollution. On the other hand, the silicone oil used in the first example is a safe liquid and is odorless, as is clear from the fact that it is used for cosmetics. , The working environment can be improved and no pollution problem will occur.

Further, according to the first embodiment, since the intermediate transfer belt 602 which is an intermediate transfer member is used, the toner image formed on the photoconductor 10 is not directly transferred to the paper.
When the liquid developer has a high concentration and a high viscosity as used in this embodiment, if the surface of the recording medium such as paper is rough, the toner image transferred onto the recording medium may cause image loss. Therefore, it is preferable to apply a certain pressing force when transferring the toner image to the recording medium. However,
When the toner image formed on the photoconductor 10 is directly transferred to the recording medium, sufficient pressure cannot be applied to the photoconductor 10. In this embodiment, since the toner image formed on the photoconductor 10 is primarily transferred onto the intermediate transfer belt 602, the toner image primarily transferred onto the intermediate transfer belt 602 is secondarily transferred onto a recording medium. A sufficient pressing force can be applied during the secondary transfer. Therefore, according to the present embodiment, the toner image primarily transferred onto the intermediate transfer belt 10 can be satisfactorily secondarily transferred onto the recording medium without causing image loss.

Further, according to the first embodiment, since the intermediate transfer belt 602 is used, in order to facilitate the movement of the toner on the photoconductor 10 to the intermediate transfer belt 602, the recording medium is pre-wet liquid. There is no need to smooth the surface of the. Therefore, if the intermediate transfer belt 602 does not absorb the pre-wetting liquid and its surface is smooth, a small amount of the pre-wetting liquid is sufficient for the primary transfer. As a result, the toner image formed on the photoconductor 10 can be primarily transferred onto the intermediate transfer belt 602 without selecting the type of the recording medium, and the pre-wetting liquid at the time of primary transfer can be reduced. That is, the amount of pre-wet liquid has come to be determined by the amount required for development.

Further, according to the first embodiment, the intermediate transfer belt 60 formed of a flexible member on the intermediate transfer body.
By using 2, it is possible to disperse the contact pressure when the toner image formed on the latent image surface of the photoconductor 10 and the intermediate transfer belt 602 are dispersed, so that the toner image is transferred onto the intermediate transfer belt 602. It is possible to prevent the toner image from being disturbed.

In addition, according to the first embodiment, since the surface layer of the intermediate transfer belt 602 is formed of a material having a good releasing property, the releasing property between the intermediate transfer belt 602 and the toner in the secondary transfer is improved. Therefore, the toner image transferred to the intermediate transfer belt 602 can be satisfactorily secondarily transferred to the recording medium.

Next, FIG. 15 shows the second embodiment of the present invention.
Will be described with reference to. FIG. 15 is a schematic configuration diagram of an image forming apparatus according to the second embodiment of the present invention. In the image forming apparatus shown in FIG. 15, those having the same functions as those in the first embodiment are designated by the same reference numerals or corresponding reference numerals, and detailed description thereof will be omitted.

Image forming apparatus 2 according to the second embodiment of the present invention
15 is different from that of the first embodiment, as shown in FIG. 15, in place of the photoconductor 10 which is an image support, the photosensitive belt 1
2 is used, and the drive rollers 122a, 122b, 12
It is held by 2c and rotated, and a transfer device 64 is used instead of the transfer device 60.

As the base material of the photosensitive belt 12, a flexible belt member such as a metal belt such as a seamless nickel belt or a resin belt such as a polyimide film belt is used. This makes it possible to disperse the contact pressure when the toner image formed on the photosensitive belt 12 and the intermediate transfer member come into contact with each other.

The transfer device 64 of the second embodiment of the present invention is different from the transfer device 60 of the first embodiment in that an intermediate transfer drum 642 is used as shown in FIG. 15, and a corona discharger 606 is used. Instead of this, a power supply device 643 for applying a bias voltage to the intermediate transfer drum 642 is provided.

The intermediate transfer drum 642 is the photosensitive belt 12
Rotates in the direction opposite to the rotation direction of. Further, the intermediate transfer drum 642 is provided with a surface layer of Teflon, silicon, polyimide or the like, which has good releasability. This is because the physical adhesion of the toner to the intermediate transfer drum 642 is weakened and the toner is easily moved to the paper.

The transfer device 64 having the above-described structure primarily transfers the toner image formed on the photosensitive belt 12 onto the intermediate transfer drum 642 by the electric field generated by the bias voltage applied to the intermediate transfer drum 642 by the power supply device. Then, the yellow, magenta, cyan, and black toner images are transferred one after another onto the intermediate transfer belt 642 to form a toner image corresponding to colorization on the intermediate transfer drum 642. The corresponding toner image is secondarily transferred to the paper, which is a recording medium, which is conveyed by the paper feeding device 610 and fed between the intermediate transfer drum 642 and the secondary transfer roller 603. The other operations of the electrostatic latent image liquid developing device according to the second embodiment are the same as those of the first embodiment, and thus detailed description thereof will be omitted.

According to the second embodiment of the present invention, since the intermediate transfer drum 642 which is an intermediate transfer member is used, the toner image formed on the photosensitive belt 12 is not directly transferred to the paper. Since the intermediate transfer drum 642 has a smooth surface and does not absorb the pre-wetting liquid like paper, a small amount of the pre-wetting liquid is required for the primary transfer. Therefore, according to the second embodiment, the toner image primarily transferred on the intermediate transfer drum 642 can be secondarily transferred satisfactorily without causing image deletion on the paper.

Further, according to the second embodiment, the toner image formed on the latent image surface of the photosensitive belt 12 is used by using the photosensitive belt 12 composed of a flexible member for the image support. Since the contact pressure at the time of contact between the intermediate transfer drum 642 and the intermediate transfer drum 642 can be dispersed, the toner image on the photosensitive belt 12 can be primarily transferred to the intermediate transfer drum 642 without being disturbed. Other effects are similar to those of the first embodiment.

Next, FIG. 16 shows the third embodiment of the present invention.
Will be described with reference to. FIG. 16 is a schematic configuration diagram of an image forming apparatus according to the third embodiment of the present invention. In the image forming apparatus of the third embodiment, 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 will be omitted.

Image forming apparatus 3 according to the third embodiment of the present invention
16 is different from that of the first embodiment, as shown in FIG. 16, the photosensitive belt 12 used in the second embodiment apparatus is used in place of the photoreceptor 10 as the image support, and the second embodiment is used. In the same manner as described above, the driving rollers 122a, 122b, and 122c hold and rotate the driving rollers. The operation of the image forming apparatus according to the third embodiment is the same as that of the first embodiment, and detailed description thereof will be omitted.

According to the third embodiment of the present invention, the photosensitive belt 12 made of a flexible member is used as the image support, and the intermediate transfer member is made of a flexible member. By using the intermediate transfer belt 602, it is possible to further disperse the contact pressure when the toner image formed on the latent image surface of the photosensitive belt 12 and the intermediate transfer belt 602 are further dispersed, and thus the intermediate transfer belt 602 is used. The primary transfer can be performed on the intermediate transfer belt 602 without disturbing the toner image of. Other effects are similar to those of the first embodiment.

In the first to third embodiments described above, as the secondary transfer of the transfer device, by applying a bias voltage to the secondary transfer roller 603, the color formed on the intermediate transfer belt 602 is changed. Although the description has been given of the case where the corresponding toner image is secondarily transferred to the paper, the present invention is not limited to this. The transfer device may be, for example, a device that secondarily transfers the toner image onto the paper by charging the secondary transfer roller 603 with a charge having a polarity opposite to that of the toner by corona discharge.

Next, the fourth embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. FIG. 17 is a schematic configuration diagram of an image forming apparatus according to the fourth embodiment of the present invention. In the image forming apparatus shown in FIG. 17, 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 will be omitted.

The image forming apparatus 4 according to the fourth embodiment of the present invention.
17 is different from that of the first embodiment in that a transfer device 60a is used instead of the transfer device 60, and a fixing device 620 is not provided separately as shown in FIG.

The transfer device 64 of the fourth embodiment of the present invention differs from the transfer device 60 of the first embodiment in that a heating roller 633 is used in place of the driving roller 604a, as shown in FIG. That is, the power supply device 609 is not provided.

The heating roller 633 is the intermediate transfer belt 60.
It follows 2 and rotates. Inside the heating roller 633,
A fixing heater 634, which incorporates, for example, a halogen lamp, which heats the inside of the intermediate transfer belt 602, is provided.
The fixing heater 634 is installed inside the intermediate transfer belt 602 because it is considered that the method of heating the inside of the intermediate transfer belt 602 is currently the best method for melting the toner secondarily transferred onto the paper. . As the fixing heater 634, for example, a ceramic heater is used in order to prevent the temperature inside the apparatus from rising and to increase the temperature rising speed of the intermediate transfer belt 602. The intermediate transfer belt 6
02 must be able to withstand heating by the fixing heater 634. Therefore, in this embodiment, the intermediate transfer belt 602 is made of a heat-resistant material such as a polyimide film belt. The fixing heater is provided inside the heating roller 633, and further, the secondary transfer roller 60 is provided.
It may be installed in No. 3.

The transfer device 60a having the above-described structure transfers the toner image corresponding to color formed on the intermediate transfer belt 602 to the intermediate transfer belt 602 of the secondary transfer roller 603.
It is separated from the intermediate transfer belt 602 having a surface layer having good releasability by the pressing force on the sheet and the heating by the fixing heater 634 of the heating roller 633, and is conveyed by the paper feeding device 610 and the intermediate transfer belt 602 and the secondary transfer roller. The sheet is moved to a sheet fed between the sheet and the sheet 603, and secondarily transferred, and at the same time, it is thermally fused and fixed. The other operations of the electrostatic latent image liquid developing device of the fourth embodiment are the same as those of the first embodiment, and therefore detailed description thereof will be omitted.

According to the fourth embodiment of the present invention, the toner image primarily transferred onto the intermediate transfer belt 602 is pressed by the secondary transfer roller 603 against the intermediate transfer belt 602 without using the electrostatic force. Since the heat from the fixing heater 634 of the heating roller 633 is used to perform the secondary transfer on the paper, it is not necessary to wet the surface of the paper with the pre-wet liquid for the purpose of improving transferability. Therefore, the toner image on the photoconductor 10 can be secondarily transferred onto the paper without being affected by the surface roughness of the paper or the water absorption of the pre-wetting liquid.

Further, according to the fourth embodiment, by heating the heating roller 633 provided inside the intermediate transfer belt 602, the toner image primarily transferred onto the intermediate transfer belt 602 is secondarily transferred onto the paper. Since the toner is melted and fixed at the same time as the transfer, the transfer device and the fixing device can be integrated, and therefore, the size of the device can be reduced. Other effects are similar to those of the first embodiment.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. FIG. 18 is a schematic configuration diagram of an image forming apparatus according to a fifth embodiment of the present invention. In the image forming apparatus shown in FIG. 18, those having the same functions as those in the first embodiment are designated by the same reference numerals or corresponding reference numerals, and detailed description thereof will be omitted.

The image forming apparatus 5 according to the fifth embodiment of the present invention.
18 is different from that of the first embodiment, as shown in FIG. 18, the photosensitive belt 12 used in the second embodiment apparatus is used in place of the photoreceptor 10 as the image support, and the second embodiment is used. In the same manner as described above, the rollers were held by the drive rollers 122a, 122b, 122c and rotationally driven, the transfer device 64a was used instead of the transfer device 60, and the fixing device 62 was used.
0 is not provided separately.

The transfer device 64a according to the fifth embodiment of the present invention is different from the transfer device 60 according to the first embodiment, as shown in FIG. 18, instead of the intermediate transfer belt 602 which is an intermediate transfer member. The use of the intermediate transfer drum 642 used in the example apparatus, the provision of a power supply device 643 for applying a bias voltage to the intermediate transfer drum 642 used in the second embodiment, and fixing in place of the secondary transfer roller 603. That is, the secondary transfer roller 603a in which the heater 634 is installed is used.

The transfer device 64a having the above-described structure primarily transfers the toner image formed on the photosensitive belt 12 onto the intermediate transfer drum 642 by the electric field generated by the bias voltage applied to the intermediate transfer drum 642 by the power supply device 643. . Then, the yellow, magenta, cyan, and black toner images are transferred one after another onto the intermediate transfer belt 642 so that a toner image corresponding to colorization is formed on the intermediate transfer drum 642. After that, the toner image corresponding to this colorization is transferred to the secondary transfer roller 603.
pressing force on the intermediate transfer drum 642 of “a” and the fixing heater 6
The sheet is separated from the intermediate transfer drum 642 having a surface layer having good releasability by being heated by the sheet 34, and is conveyed by the paper feeding device 610 and the intermediate transfer drum 642 and the secondary transfer roller 6
The sheet is moved to a sheet fed between the sheet 33 and the sheet 33, and secondarily transferred, and at the same time, it is thermally fused and fixed. Since the other operations of the electrostatic latent image liquid developing device of the fifth embodiment are the same as those of the first embodiment, detailed description thereof will be omitted.

According to the fifth embodiment of the present invention, the toner formed on the latent image surface of the photosensitive belt 12 is used by using the photosensitive belt 12 composed of a flexible member as the image support. Since the contact pressure when the image and the intermediate transfer drum 642 come into contact with each other can be dispersed, the intermediate transfer drum 64 does not disturb the toner image as in the first embodiment.
2 can be primary-transferred.

Further, according to the fifth embodiment, the toner image primarily transferred onto the intermediate transfer drum 642 is pressed and fixed on the intermediate transfer drum 642 by the secondary transfer roller 603a without utilizing electrostatic force. Since the heat from the heater 634 is used to perform the secondary transfer on the paper, it is not necessary to wet the surface of the paper with the pre-wet liquid for the purpose of improving transferability. Therefore, the toner image on the photosensitive belt 12 can be secondarily transferred onto the paper without being affected by the surface roughness of the paper or the water absorption of the pre-wetting liquid.

Further, according to the fifth embodiment, by heating the secondary transfer roller 603a, the intermediate transfer drum 6
Since the toner image primarily transferred onto 42 is secondarily transferred onto paper and then melted and fixed at the same time, the transfer device and the fixing device can be integrated, and therefore the device can be downsized. . Other effects are similar to those of the first embodiment.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. FIG. 19 is a schematic configuration diagram of an image forming apparatus according to a sixth embodiment of the present invention. Incidentally, in the image forming apparatus of the sixth embodiment, 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 will be omitted.

The image forming apparatus 6 according to the sixth embodiment of the present invention.
19 is different from that of the first embodiment, as shown in FIG. 19, the photosensitive belt 12 used in the second embodiment apparatus is used instead of the photoreceptor 10 as the image support, and the second embodiment is used. In the same manner as described above, the rollers were held and rotated by the driving rollers 122a, 122b, 122c, the transfer device 60a was used in place of the transfer device 60, and the fixing device 620 was provided separately. That is not the case.

As described in the fourth embodiment, the transfer device 60a having the above-described structure transfers the toner image formed on the intermediate transfer belt 602, which corresponds to colorization, to the secondary transfer roller 6a.
03 by pressing force to the intermediate transfer belt 602 and heating by the fixing heater 634 of the heating roller 633, the intermediate transfer belt 602 having a surface layer with good releasability is separated and conveyed by the paper feeding device 610. 6
No. 02 and the secondary transfer roller 633 are moved onto the paper, and the secondary transfer is performed, and at the same time, they are thermally fused and fixed. The other operations of the electrostatic latent image liquid developing device of the sixth embodiment are the same as those of the first embodiment.
Detailed description thereof will be omitted.

According to the sixth embodiment of the present invention, the photosensitive belt 1 having a flexible belt member as an image support.
2 and the intermediate transfer belt 602 including a flexible belt member as the intermediate transfer member, the toner image formed on the latent image surface of the photosensitive belt 12 and the intermediate transfer belt 602 are used. Since it is possible to further disperse the contact pressure at the time of contacting with, it is possible to transfer to the intermediate transfer belt 602 without disturbing the toner image.

Further, according to the sixth embodiment, the toner image primarily transferred onto the intermediate transfer belt 602 is pressed and heated by the secondary transfer roller 603 against the intermediate transfer belt 602 without utilizing electrostatic force. Fixing heater 6 for roller 633
Since the secondary transfer is performed on the paper by using the heat generated by 34, it is not necessary to wet the surface of the paper with the pre-wet liquid to improve the transferability. Therefore, the toner image on the photoconductor 10 can be secondarily transferred onto the paper without being affected by the surface roughness of the paper or the water absorption of the pre-wetting liquid.

Furthermore, according to the sixth embodiment, by heating the heating roller 633 provided inside the intermediate transfer belt 602, the toner image primarily transferred onto the intermediate transfer belt 602 is secondarily transferred onto the paper. Since the toner is melted and fixed at the same time as the transfer, the transfer device and the fixing device can be integrated, and therefore, the size of the device can be reduced. Other effects are similar to those of the first embodiment.

In the fourth to sixth embodiments described above, as the secondary transfer of the transfer device, the heating roller 633 or the secondary transfer roller 603a provided with the fixing heater 634 therein is described. It is not limited to this. The present invention only needs to press the secondary transfer roller against the intermediate transfer belt 602 via paper.
However, in this case, it is necessary to separately provide a fixing device.

In each of the embodiments other than the second and fifth embodiments, as the primary transfer of the transfer device, the corona discharger 606 charges the intermediate transfer belt 602 with an electric charge having a polarity opposite to that of the toner. Although the primary transfer of the toner image formed on the latent image surface of the photoconductor 10 on the intermediate transfer belt 602 has been described, the present invention is not limited to this. The transfer device is, for example,
A rubber roller with low electric resistance added with conductive fine particles is used as a driving roller for rotating the intermediate transfer belt, and a bias voltage is applied to the driving roller to apply a bias voltage to the intermediate transfer belt. Alternatively, the toner image may be primarily transferred onto. In addition, as shown in FIG. 14, at the transfer point between the photoconductor 10 and the intermediate transfer belt 602, a conductive sponge roller 607 is pressed from the back surface of the intermediate transfer belt 602 to apply an appropriate pressing force, and The toner image may be transferred by applying a bias voltage to the intermediate transfer belt 602 by applying a bias voltage to the roller 607.

Next, the seventh embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. 20 is a schematic configuration diagram of an image forming apparatus according to a sixth embodiment of the present invention. Incidentally, in the image forming apparatus of the seventh embodiment, 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 will be omitted.

The image forming apparatus 7 according to the seventh embodiment of the present invention.
20 is different from that of the first embodiment in that, as shown in FIG. 20, a transfer device 60b is used instead of the transfer device 60, and after the developing process is completed, the photosensitive member 10 is not transferred to the primary transfer process. That is, the drying device 90 for evaporating the pre-wet liquid is provided, and the fixing device 620 is not separately provided.

The transfer device 60b of the seventh embodiment of the present invention is different from the transfer device 60 of the first embodiment, as shown in FIG. 20, instead of the intermediate transfer belt 602.
02a is used, the heating roller 633 used in the fourth embodiment is used instead of the driving roller 604a, and the corona discharger 606 or the power supply devices 609 and 609a for primary / secondary transfer is not provided. That is.

The intermediate transfer belt 602b is formed of a flexible belt-shaped member such as a resin belt such as a polyimide film belt or a PTE film belt, or a rubber belt. This makes it possible to disperse the contact pressure when the toner image formed on the photoconductor 10 and the intermediate transfer belt 602b come into contact with each other. An adhesive layer is formed on the surface of the intermediate transfer belt 602b. As a result, the toner on the photoconductor 10 moves onto the intermediate transfer belt 602b by the physical adhesion force to the intermediate transfer belt 602b.

The adhesive layer is made of a rubber material such as natural rubber, urethane rubber, styrene-butadiene rubber, silicon rubber, fluorine-containing silicon rubber, or fluorine rubber. Silicon rubber includes methyl silicone rubber, methylphenyl silicone rubber, methylvinyl silicone rubber, methylphenylvinyl silicone rubber, fluorosilicone rubber, etc.
These are KE-42, KE12, KE-44, KE-
1300, KE-1800, and FE-123 (all are manufactured by Shin-Etsu Chemical Co., Ltd.). In particular, fluorosilicone rubber is a material suitable for secondary transfer by heating a recording medium, because the releasability from the toner improves as the temperature rises. In addition, since it does not swell in silicone oil, it is also suitable when silicone oil is used as the insulating liquid of the liquid developer.

Fluorine-containing silicone rubber includes, for example, 1,
There is 1,1-trifluoropropylmethylsiloxane rubber, which is commercially available as Silastic LS (manufactured by Dow Corning). For fluororubber, vinylidene fluoride-6-
There are fluorinated propene rubber, vinylidene fluoride-chloro-3-fluorinated ethylene rubber and the like, and these are Daier G-5.
01 and Daiel G-701 (both manufactured by Daikin Industries, Ltd.).

In the transfer device 60b having the above structure, the toner image formed on the photoconductor 10 is dried by the drying device 90 to remove the pre-wet liquid on the photoconductor 10, and then the adhesive layer on the surface of the intermediate transfer belt 602a. Primary transfer is performed on the intermediate transfer belt 602a by the physical adhesive force of. Then, on the intermediate transfer belt 602a, yellow, magenta,
By transferring the cyan and black toner images one after another, a toner image corresponding to colorization is formed on the intermediate transfer belt 602a. Thereafter, the toner image corresponding to this colorization is pressed by the secondary transfer roller 603 against the intermediate transfer belt 602a and heated by the fixing heater 634 of the heating roller 633, and the intermediate transfer belt 602a is heated.
From the intermediate transfer belt 602a conveyed by the paper feeding device 610 and fed between the intermediate transfer belt 602a and the secondary transfer roller 603 to be secondary-transferred, and at the same time thermally fused and fixed. As described above, when fluorosilicone rubber is used for the adhesive layer on the surface of the intermediate transfer belt 602a, the releasability between the intermediate transfer belt 602a and the toner is improved by the heating by the fixing heater 634, so that the toner can be more easily released. Secondary transfer can be performed. The other operations of the electrostatic latent image liquid developing device of the seventh embodiment are the same as those of the first embodiment, and therefore detailed description thereof will be omitted.

According to the seventh embodiment of the present invention, the photoconductor 10
The toner image formed on the intermediate transfer belt 6 is used by using the adhesive force of the adhesive layer on the surface of the intermediate transfer belt 602a.
02a, and then the intermediate transfer belt 602a.
The toner image primarily transferred onto the secondary transfer roller 603 is pressed against the intermediate transfer belt 602a by the secondary transfer roller 603 and the heating roller 63 is pressed.
The heat from the fixing heater 634 of No. 3 is used to secondarily transfer the image onto the paper and at the same time, the image is fixed. As a result, the toner image formed on the photoconductor 10 can be transferred onto the paper without using the electrostatic force. Therefore, in order to improve transferability, the paper is wetted with the pre-wet liquid to treat the surface of the paper. Therefore, the toner image formed on the photoconductor 10 can be transferred onto the paper without being affected by the surface roughness of the paper and the water absorption of the pre-wetting liquid. Further, since it is not necessary to charge the intermediate transfer belt 602a by corona discharge, ozone is not generated during transfer.

Further, according to the seventh embodiment, by heating the heating roller 633 provided inside the intermediate transfer belt 602a, the toner image primarily transferred onto the intermediate transfer belt 602a is secondarily transferred onto paper. At the same time, since the toner is melted and fixed on the paper, the transfer device and the fixing device can be integrated, and therefore the device can be downsized. Other effects are similar to those of the first embodiment.

Next, FIG. 21 shows the eighth embodiment of the present invention.
Will be described with reference to. 21 is a schematic configuration diagram of an image forming apparatus according to an eighth embodiment of the present invention. It should be noted that, in the image forming apparatus shown in FIG. 21, those having the same functions as those in the first embodiment are designated by the same reference numerals or corresponding reference numerals, and detailed description thereof will be omitted.

The image forming apparatus 8 according to the eighth embodiment of the present invention.
21 is different from that of the first embodiment, as shown in FIG. 21, the photosensitive belt 12 used in the apparatus of the second embodiment is used in place of the photoreceptor 10 which is the image support, and this is used in the second embodiment. In the same manner as described above, the rollers are held by the driving rollers 122a, 122b, 122c and rotationally driven, the transfer device 64b is used instead of the transfer device 60, and after the developing process is completed, the photosensitive belt 12 is transferred to the primary transfer process. A drying device 90 for evaporating the pre-wet liquid of
That is, the fixing device 620 is not separately provided.

The transfer device 64b of the eighth embodiment of the present invention is different from the transfer device 60 of the first embodiment, as shown in FIG. 21, instead of the intermediate transfer belt 602 which is an intermediate transfer member. 642a was used, and instead of the secondary transfer roller 603, the secondary transfer roller 603a used in the fifth embodiment was used.

The intermediate transfer drum 642a is the photosensitive belt 1
It is provided so as to come into contact with 2, and rotates in a direction opposite to the rotation direction of the photosensitive belt 12. An adhesive layer is formed on the surface of the intermediate transfer drum 642a. As a result, the toner on the photosensitive belt 12 is transferred to the intermediate transfer drum 6
The intermediate transfer drum 642 due to the physical adhesive force to 42a.
a Move up. The adhesive layer on the surface of the intermediate transfer drum 642a is formed by the same one as described in the seventh embodiment.

In the transfer device 64b having the above structure, the toner image formed on the photosensitive belt 12 is dried by the drying device 90 to dry the pre-wet liquid on the photosensitive belt 12, and
The primary transfer is performed on the intermediate transfer drum 642a by the adhesive force of the adhesive layer on the surface of the intermediate transfer drum 642a. Then, the yellow, magenta, cyan, and black toner images are transferred one after another onto the intermediate transfer drum 642a to form a toner image corresponding to colorization on the intermediate transfer drum 642a. Then, the toner image corresponding to this colorization is separated from the intermediate transfer drum 642a by the pressing force of the secondary transfer roller 603a to the intermediate transfer drum 642a and the heating by the fixing heater 634, and is conveyed by the paper feeding device 610. Intermediate transfer drum 6
42a and the secondary transfer roller 603a are moved onto the paper fed to perform secondary transfer, and at the same time, are thermally fused and fixed. The other operations of the electrostatic latent image liquid developing device of the eighth embodiment are the same as those of the first embodiment, and therefore detailed description thereof will be omitted.

According to the eighth embodiment of the present invention, the photosensitive belt 1 having a flexible belt member as the image support.
By using 2, it is possible to disperse the contact pressure when the toner image formed on the latent image surface of the photosensitive belt 12 and the intermediate transfer drum 642a are dispersed, so that it is the same as in the first embodiment. The toner image can be primarily transferred to the intermediate transfer drum 642a without being disturbed.

Further, according to the eighth embodiment, the photosensitive belt 1
The toner image formed on the intermediate transfer drum 642a is primarily transferred onto the intermediate transfer drum 642a by using the adhesive force of the adhesive layer on the surface of the intermediate transfer drum 642a.
The toner image primarily transferred onto the second transfer roller 60 is transferred to the secondary transfer roller 60.
3a is secondarily transferred onto the paper by using the pressing force of the intermediate transfer drum 642a on the intermediate transfer drum 642a and the heat from the fixing heater 634, and at the same time the image is fixed. As a result, the toner image formed on the photosensitive belt 12 can be transferred onto the paper without using the electrostatic force. Therefore, it is necessary to wet the surface of the paper with the pre-wetting liquid to improve the transferability. Therefore, the toner image formed on the photosensitive belt 12 can be transferred onto the paper without being affected by the surface roughness of the paper or the water absorption of the pre-wetting liquid. Moreover, since it is not necessary to charge the intermediate transfer drum 642a by corona discharge, ozone is not generated during transfer.

Further, according to the eighth embodiment, by heating the secondary transfer roller 603a, the intermediate transfer drum 6
The toner image primarily transferred onto the sheet 42a is secondarily transferred onto the paper, and at the same time, the toner image is melted and fixed on the paper, so that the transfer device and the fixing device can be integrated, so that the size of the device can be reduced. it can. Other effects are similar to those of the first embodiment.

Next, the ninth embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. 22 is a schematic configuration diagram of an image forming apparatus according to a ninth embodiment of the present invention. In the image forming apparatus of the ninth embodiment, 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 will be omitted.

The image forming apparatus 9 according to the ninth embodiment of the present invention.
22 is different from that of the first embodiment, as shown in FIG. 22, the photosensitive belt 12 used in the apparatus of the second embodiment is used in place of the photoreceptor 10 which is the image support. In the same manner as described above, the rollers were held and rotated by the driving rollers 122a, 122b, 122c, the transfer device 60b was used in place of the transfer device 60, and after the development process, the primary transfer process was performed. Drying device 9 for evaporating the pre-wet liquid on the photosensitive belt 12 before the transfer
0 is provided and the fixing device 620 is not provided separately.

As described in the seventh embodiment, the transfer device 60b having the above-described structure causes the toner image formed on the photoconductor 10 to physically adhere to the adhesive layer on the surface of the intermediate transfer belt 602a. Primary transfer is performed on the intermediate transfer belt 602a. Then, yellow on the intermediate transfer belt 602a,
By transferring the magenta, cyan, and black toner images one after another, a toner image corresponding to colorization is formed on the intermediate transfer belt 602a. After that, the toner image corresponding to this colorization is formed by pressing the secondary transfer roller 603 against the intermediate transfer belt 602 a and heating roller 63.
3 is heated by the fixing heater 634 to be separated from the intermediate transfer belt 602a, moved by the paper feeding device 610 and moved onto the paper fed between the intermediate transfer belt 602a and the secondary transfer roller 603, and the secondary transfer is performed. At the same time, it is thermally fused and fixed. The other operations of the electrostatic latent image liquid developing device of the ninth embodiment are the same as those of the first embodiment, and thus detailed description thereof will be omitted.

According to the ninth embodiment of the present invention, the photosensitive belt 1 having a flexible belt member as the image support.
2 and the intermediate transfer belt 602b formed of a flexible belt member as the intermediate transfer member, the toner image formed on the latent image surface of the photosensitive belt 12 and the intermediate transfer belt 602b are used. Since it is possible to further disperse the contact pressure at the time of contacting with, it is possible to transfer the toner image onto the intermediate transfer belt 602b without disturbing it.

Further, according to the ninth embodiment, the photosensitive belt 1
The toner image formed on the intermediate transfer belt 602a is dried on the photosensitive belt 12 by the drying device 90, and the adhesive force of the adhesive layer on the surface of the intermediate transfer belt 602a is used to form the toner image on the intermediate transfer belt 602a. Primary transfer to
The toner image primarily transferred onto the intermediate transfer belt 602a is secondarily transferred onto the paper and simultaneously fixed by using the pressing force of the secondary transfer roller 603 against the intermediate transfer belt 602a and the heat from the fixing heater 634 of the heating roller 633. . As a result, the toner image formed on the photosensitive belt 12 can be transferred onto the paper without using the electrostatic force. Therefore, it is necessary to wet the surface of the paper with the pre-wetting liquid to improve the transferability. Therefore, the toner image formed on the photosensitive belt 12 can be transferred onto the paper without being affected by the surface roughness of the paper or the water absorption of the pre-wetting liquid. Further, since it is not necessary to charge the intermediate transfer belt 602a by corona discharge, ozone is not generated during transfer.

Further, according to the ninth embodiment, by heating the heating roller 633 provided inside the intermediate transfer belt 602a, the toner image primarily transferred onto the intermediate transfer belt 602b is secondarily transferred onto the paper. Since the toner is melted and fixed at the same time as the transfer, the transfer device and the fixing device can be integrated, and therefore, the size of the device can be reduced. Other effects are similar to those of the first embodiment.

The present invention is not limited to the above embodiments, but various modifications can be made within the scope of the invention. For example, in each of the above-described embodiments, the pre-wet liquid supply body 202 is used as the pre-wetting device for the photoconductor 1
Although the pre-wetting liquid 220 is applied to the surface of No. 0, the present invention is not limited to this, and the pre-wetting device applies a constant amount of the pre-wetting liquid to the surface of the photoconductor uniformly. Anything can be done. For example, it may be applied by ejecting the pre-wet liquid from a plurality of nozzles arranged in the axial direction, or applied by a sponge roller or the like.

Further, in each of the above-described embodiments, the flexible belt member is used for at least one of the image support and the intermediate transfer member, but the present invention is not limited to this. Absent.

In each of the above-described embodiments, the developing device using the developing belt 510 composed of a flexible member as the developer support has been described, but the present invention is not limited to this. Instead, the developing device may use a rigid roller made of metal or the like or an elastic roller made of an elastic material having conductivity on the developer support. However, when a rigid roller is used, since the liquid developer layer formed on the rigid roller and the pre-wet liquid layer formed on the photoconductor are brought into contact with each other while maintaining a two-layer state, they are flexible to the image support. It is necessary to use a member made of a material having good properties or to provide a rigid roller so as to form a minute gap between the rigid roller and the photoconductor.

Furthermore, in each of the above-described embodiments, the developer supply device provided with four developing cartridges has been described, but the present invention is not limited to this. The developer supply device may be provided with one, two or three developing cartridges for applying a liquid developer of a desired color onto the developer support.

Further, in each of the above embodiments, the exposure device 4
The image is exposed on an image support charged by 0 and then
Although the pre-wetting device 20 applies the pre-wetting liquid 220 onto the image support, the present invention is not limited to this, and the pre-wetting liquid is applied prior to the developing step. If
The pre-wetting liquid has a viscosity of 0.5 to 5 mPa ·
s, electric resistance is 10 ¹² Ωcm or more, boiling point is 100 to 25
If the temperature is 0 ° C. and the surface tension is 21 dyn / cm, silicon does not have to be the main component. Further, when the surface of the image support is coated with a material having releasability, a pre-wetting step is not particularly required.

Further, in each of the above-mentioned embodiments, the case where the organic photoconductor is used as the image support has been described, but the present invention is not limited to this, and the image support can be various types used in the Carlson method. An electrostatic recording paper such as an electrostatic plotter in which an insulating layer is formed on a photoconductor or a conductor for directly forming an electrostatic latent image such as ionography, may be used. Further, it is not limited to the liquid developing device for the electrostatic latent image corresponding to the color.

The present invention is not limited to the above-mentioned embodiments, and the viscosity of the high-viscosity developer may be 10,000 mPa · s as long as the layer thickness of the liquid developer is 5 to 40 μm. . At present, a developer with a high viscosity of 6000 mPa · s or more is difficult to agitate between the carrier liquid and the toner, so it is thought to be costly. Good. If the viscosity exceeds 10,000 mPa · s, it becomes unrealistic. Further, the carrier liquid of the liquid developer is not limited to silicone oil.

[0154]

As described above, according to the first aspect of the present invention, a high-viscosity liquid developer in which toner is dispersed in a high concentration is developed in a thin layer for development, thereby achieving high resolution and miniaturization. It is easy, and it is possible to reduce pollution.
By using the intermediate transfer member, sufficient pressing force can be applied at the time of the secondary transfer, so that the toner image primarily transferred on the intermediate transfer member can be imaged on a recording medium having a rough surface such as paper. It is possible to provide an image forming method capable of favorably performing secondary transfer without causing omission.

According to the second aspect of the invention, at least one of the image support and the intermediate transfer member is formed of a flexible thin plate member, so that it is formed on the latent image surface of the image support. Since it is possible to disperse the contact pressure when the toner image and the intermediate transfer member come into contact with each other, it is possible to prevent the toner image primarily transferred on the intermediate transfer member from being crushed and disturbed. It is possible to provide an image forming method capable of transferring a toner image formed on a support onto a recording medium without causing image deletion.

According to the third aspect of the invention, by using electrostatic transfer in the primary transfer step, it is possible to provide an image forming method having the same effect as that of the first aspect of the invention.

According to the fourth aspect of the present invention, since the surface layer of the intermediate transfer member is made to have a good releasability, the releasability between the intermediate transfer member and the toner is improved. It is possible to provide an image forming method capable of favorably secondary-transferring a primary-transferred toner image to a recording medium.

According to the invention of claim 5, an adhesive layer is formed on the surface of the intermediate transfer member, and the toner image formed on the image support is primarily transferred onto the intermediate transfer member by the adhesive force of the intermediate transfer member. By transferring, the toner image formed on the image support can be transferred onto the recording medium without using the electrostatic force, so that it is not necessary to wet the surface of the recording medium with the pre-wetting liquid for treatment. , Therefore
The toner image formed on the image support can be satisfactorily transferred onto the recording medium regardless of the surface roughness of the recording paper of the recording medium and the water absorption of the pre-wetting liquid, and the intermediate transfer can be performed during the primary transfer. Since a power supply device for applying to the body is not required and further, the intermediate transfer body does not need to be charged by corona discharge, it is possible to provide an image forming method in which ozone is not generated during the primary transfer.

In the image forming method according to the sixth aspect, since the adhesive layer of the intermediate transfer member is formed of fluorosilicone rubber, the fluorosilicone rubber improves the releasability from the toner by heating, so that the intermediate transfer member is improved. To provide an image forming method capable of excellent secondary transfer of a toner image primary-transferred onto a recording medium without utilizing electrostatic force, and thus not requiring a power supply device for secondary transfer. You can

According to the invention described in claim 7, by using electrostatic transfer in the secondary transfer step, it is possible to provide an image forming method having the same effect as that of the invention described in claim 1.

According to the eighth aspect of the present invention, the toner image primarily transferred onto the intermediate transfer member is pressed onto the recording medium and the intermediate transfer member is pressed against the intermediate transfer member without using electrostatic force. The toner image that has been primarily transferred onto the transfer body is heated and then secondarily transferred and fixed at the same time, so there is no need to provide a means for applying an electrostatic force for secondary transfer, and the surface of the recording medium is pre-wet. Since it is not necessary to wet the liquid for processing, the secondary transfer can be satisfactorily performed regardless of the surface roughness of the recording paper of the recording medium and the water absorption of the pre-wet liquid. Therefore, it is possible to provide an image forming method which can be integrated, and which can reduce the size of the apparatus.

According to the ninth aspect of the present invention, prior to the developing step, a pre-wet liquid that is a dielectric liquid that is releasable and chemically inert is applied onto the image support. By including the step, it is possible to provide the image forming method capable of preventing the toner from adhering to the non-image portion on the image support during the developing step.

According to the tenth aspect of the invention, since the pre-wetting liquid has the characteristics described above, in addition to the above effects, the releasability at the time of transfer can be improved. Can be provided.

According to the eleventh aspect of the present invention, since the pre-wetting liquid contains silicon oil as a main component, in addition to the above effects, there is less pollution and the working environment can be improved. It is possible to provide a possible image forming method.

According to the twelfth aspect of the present invention, the insulating liquid of the liquid developer having the above characteristics is used.
In addition to the effect of the invention described in claim 1, it is possible to provide an image forming method having good wettability of a liquid developer.

According to the thirteenth aspect of the present invention, since the insulating liquid contains silicon oil as a main component, in addition to the effect of the twelfth aspect of the invention, there is little pollution and the working environment is improved. It is possible to provide an image forming method capable of achieving the above.

According to the fourteenth aspect of the present invention, in addition to the above effects, the liquid developer contains the toner having the average particle diameter of 0.1 to 5 μm in the concentration of 5 to 40%.
It is possible to provide an image forming method in which the toner is easily peeled off during transfer.

According to the fifteenth aspect of the invention, with the above configuration, it is possible to provide an image forming apparatus having the same effect as the effect of the first aspect of the invention.

According to the sixteenth aspect of the invention, with the above configuration, it is possible to provide an image forming apparatus having the same effect as that of the second aspect of the invention.

According to the seventeenth aspect of the invention, with the above configuration, it is possible to provide an image forming apparatus having the same effect as the effect of the third aspect of the invention.

According to the eighteenth aspect of the invention, with the above configuration, it is possible to provide an image forming apparatus having the same effect as the effect of the fourth aspect of the invention.

According to the nineteenth aspect of the invention, with the above configuration, it is possible to provide the image forming apparatus having the same effect as the effect of the fifth aspect of the invention.

According to the twentieth aspect of the invention, with the above structure, it is possible to provide an image forming apparatus having the same effect as that of the sixth aspect of the invention.

According to the twenty-first aspect of the invention, by virtue of the above construction, it is possible to provide an image forming apparatus having the same effect as the effect of the seventh aspect of the invention.

According to the twenty-second aspect of the invention, with the above-mentioned structure, it is possible to provide an image forming apparatus having the same effect as that of the eighth aspect of the invention.

According to the twenty-third aspect of the invention, with the above configuration, it is possible to provide the image forming apparatus having the same effect as the effect of the ninth aspect of the invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus that is a first embodiment of the present invention.

FIG. 2 is a schematic perspective view of a pre-wetting device used in the image forming apparatus shown in FIG.

FIG. 3 is a diagram for explaining the operation of the image forming apparatus shown in FIG.

FIG. 4 is a diagram for explaining the operation of the pre-wetting device shown in FIG.

FIG. 5 is a diagram showing a flow of the pre-wet liquid when the pre-wet liquid supply body is brought into contact with the photoconductor.

FIG. 6 is a diagram for explaining the entire developing process.

FIG. 7 is a diagram showing a state of an approaching process.

FIG. 8 is a diagram showing a state of a toner movement process.

FIG. 9 is a diagram showing a separation process of a non-image portion.

FIG. 10 is a diagram showing a process of separating an image portion.

FIG. 11 is a diagram for explaining the significance of thinning the liquid developer.

FIG. 12 is a diagram showing a state in which a developing roller and a photoconductor are in hard contact.

FIG. 13 is a diagram for explaining soft contacts of the image forming apparatus according to the first embodiment.

FIG. 14 is a diagram showing a modification of the transfer device used in the image forming apparatus according to the first embodiment.

FIG. 15 is a schematic configuration diagram of an image forming apparatus that is a second embodiment of the present invention.

FIG. 16 is a schematic configuration diagram of an image forming apparatus that is a third embodiment of the present invention.

FIG. 17 is a schematic configuration diagram of an image forming apparatus that is a fourth embodiment of the present invention.

FIG. 18 is a schematic configuration diagram of an image forming apparatus that is a fifth embodiment of the present invention.

FIG. 19 is a schematic configuration diagram of an image forming apparatus that is a sixth embodiment of the present invention.

FIG. 20 is a schematic configuration diagram of an image forming apparatus that is a seventh embodiment of the present invention.

FIG. 21 is a schematic configuration diagram of an image forming apparatus that is an eighth embodiment of the present invention.

FIG. 22 is a schematic configuration diagram of an image forming apparatus that is a ninth embodiment of the present invention.

[Explanation of symbols]

1, 2, 3, 4, 5, 6, 7, 8, 9 Image forming apparatus 10 Photoconductor 12 Photosensitive belt 20 Pre-wetting device 30 Charging device 40 Exposure device 50 Developing device 51 Developer supplying device 51a, 51b, 51c, 51d developing cartridge 60, 60a, 60b, 64, 64a, 64b transfer device 70 cleaning device 80 charge eliminating device 90 drying device 122a, 122b, 122c, 512a, 512b,
512c, 604a, 604b, 604c Drive roller 202 Pre-wet liquid supply body 204 Case 206, 502 Tank 208 Pump 210a, 210b Tube 212 Displacement device 220 Pre-wet liquid 502a Discharge roller 504 Supply roller 506 Coating roller 508a, 508b, 508c, 508d Liquid developer 509 Rotating shaft 510 Developing belt 602, 602a Intermediate transfer belt 603, 603a Secondary transfer roller 605a, 605b Holding roller 606 Corona discharger 607 Sponge roller 609, 643 Power supply device 610 Paper feeding device 620 Fixing device 622 Fixing roller 624 , 634 Fixing heater 633 Heating roller 642, 642a Intermediate transfer drum

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Hasegawa 2-6-3 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Steel Corporation

Claims (23)

[Claims] 1. An electrostatic latent image formed on an image support,
An image forming method of developing with a toner which is a charged image-forming particle and transferring the toner image formed on the image support to a recording medium, which comprises: an insulating liquid coated on a developer support; A developing step of forming a toner image on the image support by supplying a high-viscosity liquid developer of 100 to 10,000 mPa · s in which the toner is highly concentrated to the latent image surface of the image support. A primary transfer step of primarily transferring the toner image formed on the image support onto an intermediate transfer body; and a secondary transfer step of secondary transfer of the toner image primarily transferred onto the intermediate transfer body onto a recording medium. An image forming method, comprising: 2. The image forming method according to claim 1, wherein at least one of the image support and the intermediate transfer member is formed of a flexible thin plate member. 3. The primary transfer process according to claim 1, wherein the toner image formed on the image support is primary-transferred onto the intermediate transfer body by an electrostatic force. Image forming method. 4. The image forming method according to claim 3, wherein the intermediate transfer member has a surface layer having good releasability. 5. The intermediate transfer member has an adhesive layer formed on the surface thereof, and in the primary transfer step, the toner image formed on the image support is transferred by the adhesive force of the intermediate transfer member. The image forming method according to claim 1, wherein the image is primarily transferred onto an intermediate transfer member. 6. The image forming method according to claim 5, wherein the adhesive layer of the intermediate transfer member is formed of fluorosilicone rubber. 7. The secondary transfer step is a secondary transfer of the toner image primarily transferred onto the intermediate transfer member onto the recording medium by electrostatic force. , 3 or 4, the image forming method. 8. The secondary transfer step comprises pressing the secondary transfer member against the intermediate transfer member via the recording medium and heating the toner image primarily transferred onto the intermediate transfer member, The image forming method according to claim 1, wherein the toner image primarily transferred onto the intermediate transfer member is secondarily transferred onto the recording medium and then fixed simultaneously. Method. 9. A pre-wetting step of applying a pre-wetting liquid, which is a dielectric liquid having releasability and chemically inert, onto the image support prior to the developing process. Claims 1, 2, 3, 4, 5, 6, 7 or 8
The image forming method described. 10. The pre-wet liquid has a viscosity of 0.5.
10. The image forming method according to claim 9, wherein the electric resistance is 10 ¹² Ωcm or more, the boiling point is 100 to 250 ° C., and the surface tension is 21 dyn / cm or less. 11. The pre-wetting liquid contains silicone oil as a main component.
The image forming method described in 0. 12. The liquid developer has an insulating liquid having a viscosity of 0.5 to 1000 mPa · s and an electric resistance of 10 ¹² Ωc.
m or more, surface tension 21 dyn / cm or less, boiling point 10
4. The temperature is 0 ° C. or higher.
The image forming method described in 4, 5, 6, 7, 8, 9, 10 or 11. 13. The image forming method according to claim 12, wherein the liquid developer uses silicon oil as an insulating liquid. 14. The liquid developer has an average particle diameter of 0.1 to 0.1.
5. A toner containing 5 .mu.m at a concentration of 5 to 40%, wherein the toner is 5 to 40%.
The image forming method described in 8, 9, 10, 11, 12 or 13. 15. An electrostatic latent image formed on an image support is developed with a toner which is a charged image-forming particle,
An image forming apparatus for transferring a toner image formed on the image support to a recording medium, wherein the toner is dispersed at a high concentration in an insulating liquid coated on a developer support and has a density of 100 to 10,000 mPa. developing means for forming a toner image on the image support by supplying a high-viscosity liquid developer of s to the latent image surface of the image support; and a toner image formed on the image support. An image forming device comprising: a primary transfer unit that primarily transfers the toner onto the intermediate transfer member; and a secondary transfer unit that secondarily transfers the toner image primarily transferred onto the intermediate transfer member onto a recording medium. apparatus. 16. The image forming apparatus according to claim 15, wherein at least one of the image support and the intermediate transfer member is formed of a flexible thin plate member. 17. The primary transfer means primary transfers the toner image formed on the image support member onto the intermediate transfer member by an electrostatic force. Image forming apparatus. 18. The image forming apparatus according to claim 17, wherein the intermediate transfer member has a surface layer having good releasability. 19. The intermediate transfer body has an adhesive layer formed on the surface thereof, and the primary transfer means transfers the toner image formed on the image support by the adhesive force of the intermediate transfer body. The image forming method according to claim 15 or 16, wherein the image is primarily transferred onto an intermediate transfer member. 20. The adhesive layer of the intermediate transfer member is formed of fluorosilicone rubber.
9. The image forming apparatus according to item 9. 21. The secondary transfer means secondary transfers the toner image primarily transferred onto the intermediate transfer member onto the recording medium by an electrostatic force. The image forming apparatus according to claim 17, 17 or 18. 22. The secondary transfer means presses the secondary transfer member against the intermediate transfer member via the recording medium,
16. The toner image primary-transferred onto the intermediate transfer member is secondarily transferred onto the recording medium and fixed at the same time by heating the toner image on the intermediate transfer member. , 16, 17, 18, 19 or 2
The image forming apparatus according to item 0. 23. The method according to claim 15, further comprising a pre-wetting step of applying a pre-wetting liquid, which is a dielectric liquid having releasability and chemically inert, onto the image support. The image forming apparatus according to 16, 17, 18, 19, 20, 21 or 22.