JP4185742B2 - Image forming apparatus - Google Patents

Image forming apparatus Download PDF

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Publication number
JP4185742B2
JP4185742B2 JP2002274611A JP2002274611A JP4185742B2 JP 4185742 B2 JP4185742 B2 JP 4185742B2 JP 2002274611 A JP2002274611 A JP 2002274611A JP 2002274611 A JP2002274611 A JP 2002274611A JP 4185742 B2 JP4185742 B2 JP 4185742B2
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Japan
Prior art keywords
liquid
transfer
toner
fixing
transfer belt
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JP2002274611A
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Japanese (ja)
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JP2004109749A (en
Inventor
英宗 大嶽
則康 竹内
恒夫 黒鳥
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株式会社リコー
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Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer. More specifically, the present invention relates to an image forming apparatus that applies a fixing solution that dissolves or swells toner to the toner to fix the toner on a recording material.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known an image forming apparatus that employs a thermal fixing method in which toner on a recording material is heated and melted and pressurized to fix the toner on the recording material. In this type of image forming apparatus, 50% or more of the power consumption is consumed for the heat treatment in the fixing unit. Therefore, suppressing power consumption in the fixing unit is effective as an energy saving measure for the entire image forming apparatus. Conventionally, various fixing methods that do not employ the thermal fixing method have been proposed. Among them, there is known a wet fixing method in which a fixing process is performed using a fixing solution that dissolves or swells toner. In this wet fixing method, a toner is fixed on a recording material by applying a fixing solution to the toner and dissolving or swelling the toner. This method is an excellent fixing method as an energy saving measure because a heat treatment with a large amount of power consumption like the heat fixing method is not required. In addition, since warm-up time as in the heat fixing method is not required, quick start is possible. Examples of the image forming apparatus that employs the wet fixing method include those disclosed in Patent Document 1, Patent Document 2, Patent Document 3, and the like.
[0003]
[Patent Document 1]
Japanese Patent No. 3290513
[Patent Document 2]
JP-A-8-72386
[Patent Document 3]
JP-A-9-78039
[0004]
[Problems to be solved by the invention]
However, in the conventional wet fixing method, since the fixing liquid is applied to the entire surface of the recording material with the toner attached thereto, the fixing liquid is also applied to the surface of the recording material on which the toner is not attached. As described above, the fixing liquid applied to the surface portion of the recording material on which the toner is not attached is useless that does not participate in toner fixing. As a result, since the amount of the fixing liquid consumed for one image formation increases, there is a problem that the fixing liquid tank for storing the fixing liquid becomes large and the apparatus becomes large.
[0005]
In order to reduce the fixing liquid tank in order to solve this problem, it is important to reduce the amount of the fixing liquid applied to the toner as much as possible and to suppress the amount of the fixing liquid consumed for one image formation. Here, the present applicant has proposed an image forming apparatus that applies the fixing liquid so that the fixing liquid adheres only to the toner and does not adhere to the surface portion of the recording material on which the toner is not carried. According to this image forming apparatus, useless fixing liquid application that does not involve toner fixing is not performed, so that the amount of fixing liquid consumed during one image formation can be reduced. However, even in this image forming apparatus, in order to fix the toner on the recording material, it is necessary to attach a minimum amount of fixing solution capable of sufficiently dissolving or swelling the toner to the toner. It cannot be reduced any further.
[0006]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of reducing the size of the fixing liquid tank by reducing the amount of the fixing liquid applied to the toner. Is to provide.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, the invention of claim 1 includes a latent image carrier, a developing means for developing a latent image on the latent image carrier, and the latent image carrier formed by the developing means. A first transfer means for transferring the toner image onto the intermediate transfer member, a second transfer means for transferring the toner image transferred onto the intermediate transfer member onto the recording material, and dissolving or swelling the toner. In an image forming apparatus including a fixing unit that applies a fixing liquid to the toner and fixes the toner on a recording material, the developing unit performs development with a liquid developer in which the toner is dispersed in a carrier liquid. Using the liquid developing means, the fixing means isThe intermediate transfer member has a supply roller that is in contact with the surface of the intermediate transfer member or is opposed to the intermediate transfer member with a predetermined interval, and supplies the fixing liquid to the surface of the intermediate transfer member.Before the toner image on the intermediate transfer member is transferred onto the recording material, the fixing liquid is applied to the toner carried on the surface of the intermediate transfer member.When the fixing liquid is supplied by the supply roller, an electric field forming unit is provided for forming an electric field in a direction in which the toner carried on the surface of the intermediate transfer member is pressed against the intermediate transfer member.It is characterized by.
  MaClaim2The invention of claim1In the image forming apparatus, the liquid component is the same substance as the carrier liquid.
  Claims3The invention of claimOne or twoIs2In the image forming apparatus, the intermediate transfer member having a release layer on the surface thereof is used..
  MaClaim4The invention of claim 1To any one of 3In the image forming apparatus of the present invention, the image forming apparatus has a collection roller that is disposed so as to be in contact with the surface of the intermediate transfer member or to face the intermediate transfer member with a predetermined gap therebetween, and to collect an excess of the fixing solution supplied to the surface of the intermediate transfer member Before transferring the toner image on the intermediate transfer member onto the recording material, an excess liquid removing means for removing the excess by adhering to the surface of the collecting roller is provided. It is characterized by using a material having a mold layer.
  Claims5The invention of claim 1To any one of 4In this image forming apparatus, before transferring the toner image on the intermediate transfer member onto the recording material, there is provided an excess liquid removing unit that removes an excess of the fixing solution supplied to the surface of the intermediate transfer member. An electric field forming means is provided for forming an electric field in a direction in which the toner carried on the surface of the intermediate transfer body is pressed against the intermediate transfer body when the excess liquid is removed by the excess liquid removing means. .
[0008]
  The present inventionIn the above, a toner image on a latent image carrier formed by a liquid developer is transferred onto an intermediate transfer member, a fixing solution is applied to the toner on the intermediate transfer member, and then this is applied to a recording material. Transcript. The amount of carrier liquid adhering to the latent image carrier can be halved by the transfer process from the latent image carrier to the intermediate transfer member. Therefore, compared to the configuration in which the fixing liquid is applied to the toner on the latent image carrier, the carrier liquid that adheres to the toner to which the fixing liquid is applied becomes less. Accordingly, the time required for the dissolving / swelling component in the fixing solution to reach the toner can be shortened, and the reaction time between the resin component of the toner and the dissolving / swelling component in the fixing solution can be shortened.
  Here, the image forming apparatus employs a liquid development system in which development is performed using a liquid developer in which toner is dispersed in a carrier liquid. This liquid development method can form a toner image with a smaller amount of toner than the dry development method. Therefore, if the liquid development method is employed, the amount of toner adhering to the intermediate transfer member can be reduced as compared with the dry development method even when image formation with the same image area ratio is performed. As a result, it is possible to reduce the minimum amount of the fixing solution that can sufficiently dissolve or swell the toner on the intermediate transfer member. Therefore, it is possible to reduce the amount of fixing liquid applied to the toner.
[0009]
  In addition, as a result of further research, the inventors of the present invention have a configuration in which the fixing liquid is applied to the toner on the intermediate transfer member of the image forming apparatus that employs the liquid developing method as described above. It was found that such a problem occurred.
  The present inventors conducted various experiments in which the wet fixing method according to the above application is applied to a liquid developing type image forming apparatus. As a result of the experiment, it becomes clear that there is a difference in the reaction time between the resin component of the toner and the dissolving / swelling component in the fixing liquid depending on the combination of the liquid component of the fixing liquid and the carrier liquid of the liquid developer. It was. In particular, in recent years, in consideration of the environment, a fixing solution using water as a liquid component instead of volatile organic compounds (VOC) such as toluene may be used. Results in a large delay. This is because a highly insulating oily material such as silicone oil, normal paraffin, Isopar M (registered trademark), vegetable oil, or mineral oil is generally used as the carrier liquid for the liquid developer. That is, it was found that when the fixing solution was applied to the toner to which such a carrier solution was adhered, the carrier solution repels the water in the fixing solution and the reaction was greatly delayed.
  Therefore, KiUse a fixer containing a liquid component that easily mixes with the carrier solution.Is preferred. As a result, the time required for the dissolving / swelling component in the fixing solution to reach the toner can be shortened, and the reaction time between the resin component of the toner and the dissolving / swelling component in the fixing solution can be shortened.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is applied to an electrophotographic color copier (hereinafter simply referred to as “copier”) as an image forming apparatus will be described below. The copying machine of the present embodiment is a so-called tandem type color image forming apparatus that employs a liquid developing system and includes an intermediate transfer belt that is an intermediate transfer member.
FIG. 2 is a schematic configuration diagram of the entire copying machine according to the present embodiment. The copying machine includes a copying machine main body 100, a paper feed table 200 on which the copying machine main body is placed, a scanner 300 mounted on the copying machine main body, and an automatic document feeder (ADF) mounted on the scanner. 400.
[0011]
FIG. 3 is an enlarged view showing the configuration of the copying machine main body 100 portion. The copying machine main body 100 is provided with an intermediate transfer belt 10. The intermediate transfer belt 10 is rotationally driven in the clockwise direction in FIG. 3 while being stretched around the support rollers 14, 15, and 16 that are three support members. Of the support rollers, four image forming units 18Y, 18C, 18M, and 18BK of yellow, cyan, magenta, and black are arranged in a belt stretch portion between the first support roller 14 and the second support roller 15. Has been placed. Above these image forming units 18Y, 18C, 18M, and 18BK, an exposure device 21 is provided as shown in FIG. The exposure device 21 forms an electrostatic latent image on the photosensitive drums 20Y, 20C, 20M, and 20BK as latent image carriers provided in each image forming unit based on the image information of the original read by the scanner 300. Is to do. A secondary transfer device 22 as a second transfer unit is provided at a position facing the third support roller 16 among the support rollers. The secondary transfer device 22 has a configuration in which an endless belt-like secondary transfer belt 24 that is a transfer member as a surface moving member is stretched between two rollers 23a and 23b. When the toner image on the intermediate transfer belt 10 is secondarily transferred onto a transfer sheet as a recording material, the secondary transfer belt 24 is pressed against the portion of the intermediate transfer belt 10 that is wound around the third support roller 16. Next transfer is performed. Note that the secondary transfer device 22 may not be configured using the secondary transfer belt 24 but may be configured using a transfer roller, for example. Further, a belt cleaning device 17 is provided at a position facing the second support roller 15 among the support rollers of the intermediate transfer belt 10. The belt cleaning device 17 is for removing residual toner remaining on the intermediate transfer belt 10 after the toner image on the intermediate transfer belt 10 is transferred to the transfer paper.
[0012]
Next, the configuration of the image forming units 18Y, 18C, 18M, and 18BK will be described. In the following description, the image forming unit 18BK that forms a black toner image will be described as an example, but the other image forming units 18Y, 18C, and 18M have the same configuration. Note that the image forming units 18Y, 18C, 18M, and 18BK can be configured as a process cartridge including at least the photosensitive drum 20 and all or a part of the components and components that constitute the image forming unit. In this case, the image forming units 18Y, 18C, 18M, and 18BK can be configured to be detachable from the copying machine main body 100, so that maintainability is improved.
[0013]
FIG. 4 is an enlarged view showing the configuration of two adjacent image forming units 18M and 18BK. In addition, in the code | symbol in a figure, the symbol of "M" and "BK" which shows distinction of a color is abbreviate | omitted, and a symbol is abbreviate | omitted suitably also in the following description.
In the image forming unit 18, a charging device 60, a liquid developing device 61, a photoconductor cleaning device 63, and a charge removal device 64 are provided around the photoconductor drum 20. A primary transfer device 62 serving as a first transfer unit is provided at a position facing the photosensitive drum 20 via the intermediate transfer belt 10.
[0014]
The charging device 60 is of a contact charging type employing a charging roller, and uniformly charges the surface of the photosensitive drum 20 by applying a voltage while contacting the photosensitive drum 20. As the charging device 60, a non-contact charging type using a non-contact scorotron charger or the like can be used.
[0015]
The liquid developing device 61 employs a liquid developing system that uses a liquid developer in which toner is dispersed in a carrier liquid. Each color toner used in the present embodiment is made of a resin material colored in each color, and is formed of a material that can be dissolved or swelled by a fixing solution described later. The liquid developer used in this embodiment is a highly viscous and high concentration liquid developer. The viscosity and concentration range of this liquid developer are, for example, a viscosity of 50 to 10,000 [mPa · s] and a concentration of 5 [%] to 40 [%]. As the carrier liquid, a highly insulating material such as silicone oil, normal paraffin, Isopar (registered trademark) M, vegetable oil or mineral oil is used. Volatile and non-volatile can be selected according to the purpose. The particle size of the toner can be selected according to the purpose from the submicron unit to about 6 [μm].
[0016]
The liquid developing device 61 includes a developing roller 65 as a developer carrying member, a coating roller 66a and a pumping roller 66b for supplying the developer to the developing roller 65, and a developer storage tank 67 for storing the liquid developer therein. It has. A fine groove having a uniform pattern is formed on the surface of the application roller 66 a, and the liquid developer is received from the pumping roller 66 b immersed in the liquid developer in the developer storage tank 67. The liquid developer thus received is carried in a state where it enters the groove on the surface of the application roller 66a, and the liquid developer attached to the outside of the groove is scraped off by the scraping blade 66c. The liquid developer on the application roller 66a is conveyed to a contact position with the development roller 65 as the application roller 66a rotates. At this contact position, the developing roller 65 and the coating roller 66a are moved in the counter direction, and the liquid developer inside the groove of the coating roller 66a adheres to the surface of the developing roller 65. Therefore, the amount of liquid developer on the developing roller 65 can be adjusted to an appropriate amount by adjusting the internal volume of the groove provided on the surface of the application roller 66a.
[0017]
In this embodiment, the thickness of the developer applied on the developing roller 65 is set to 1 [cm on the surface thereof.2] Was set so that the amount of toner carried per unit was 3 [μg] or more and 60 [μg] or less. Specifically, the thickness is set to be 3 [μm] or more and 12 [μm] or less. The range is set so that when the toner amount is smaller than 3 [μg], a sufficient amount of toner does not move to the latent image portion on the photosensitive drum 20, and a sufficient image density is obtained. This is because it is difficult to obtain. On the other hand, when the amount of toner exceeds 60 [μg], the amount of toner that adheres to the background portion on the photosensitive drum 20 after development increases, and this is completely removed by the sweep roller 68 described later. This is because it becomes difficult.
[0018]
A sweep roller 68 is disposed on the downstream side in the surface movement direction of the photosensitive drum 20 with respect to the development region. The sweep roller 68 is pressed against the photosensitive drum 20 side, and its surface is driven in a rotational direction at substantially the same speed as the surface of the photosensitive drum. Thereby, the toner adhering to the non-latent image portion (background portion) on the photosensitive drum is removed. The liquid developer removed by the sweep roller 68 is removed from the surface of the sweep roller 68 by the cleaning blade 68a in order to maintain the removal performance of the sweep roller 68. The liquid developer removed from the sweep roller 68 is collected in an adjustment tank (not shown). After adjusting the toner concentration, the liquid developer is sent again into the developer storage tank 67. In the adjustment tank, stirring means, concentration detection means, liquid amount detection means, and the like are provided, and the toner concentration is adjusted by appropriately supplying a new liquid developer or carrier liquid.
[0019]
The developing roller 65 and the sweep roller 68 have a conductive elastic layer formed on the outer peripheral surface thereof. As the material of the elastic layer, urethane rubber or the like can be used. The surface hardness of the elastic layer is desirably 50 degrees or less in terms of JIS-A hardness so that a nip can be efficiently formed with the photosensitive drum 20. The material of the elastic layer is not limited to urethane rubber, but may be any material that has conductivity and does not swell or dissolve with the carrier liquid. Moreover, if it is set as the structure which a carrier liquid does not contact by providing a coat layer on the surface of the elastic body layer, the material of the elastic body layer should just have elasticity. Further, instead of giving elasticity to the developing roller 65 and the sweep roller 68, for example, an endless belt-like photosensitive belt can be adopted instead of the photosensitive drum, and the configuration can be applied to the photosensitive drum side. It is. In addition, the surfaces of the developing roller 65 and the sweep roller 68 have a smoothness of 5 [μm] or less in terms of Rz.
[0020]
When the developing roller 65 and the sweep roller 68 configured as described above are brought into contact with the photosensitive drum 20 with an appropriate pressure, the elastic body layer of each roller is elastically deformed to form a development nip and a removal nip. The The nip width in the surface movement direction of the photosensitive drum 20 can be adjusted by changing the contact pressure. Each nip width is set to be equal to or greater than the product of the linear speed of each roller and the development time constant. Here, the development time constant is the time required until the development amount is saturated, and is obtained by dividing the necessary minimum nip width by the process speed. For example, if the required minimum nip width is 3 [mm] and the process speed is 300 [mm / sec], the development time constant is 10 [msec].
[0021]
The primary transfer device 62 employs a primary transfer roller, and is installed so as to be pressed against the photosensitive drum 20 with the intermediate transfer belt 10 interposed therebetween. The primary transfer device 62 may not be a roller shape, but may be a conductive brush shape, a non-contact corona charger, or the like. In addition, between each primary transfer device 62, a conductive roller 74 that contacts the back surface, that is, the inner peripheral surface side of the intermediate transfer belt 10 is provided. The conductive roller 74 prevents a bias applied by each primary transfer device 62 during primary transfer from flowing into an adjacent image forming unit through a layer on the inner peripheral surface side of the intermediate transfer belt 10.
[0022]
The photoconductor cleaning device 63 includes a cleaning blade 75 made of, for example, polyurethane rubber, which is disposed so that the front end is pressed against the photoconductor drum 20. In this embodiment, in order to improve the cleaning performance, a conductive fur brush 76 that contacts the photosensitive drum 20 is also used. A bias is applied to the fur brush 76 from a metal electric field roller 77, and the tip of a scraper 78 is pressed against the electric field roller 77. The toner removed from the photoconductor drum 20 by the cleaning blade 75 and the fur brush 76 is accommodated in the photoconductor cleaning device 63. Thereafter, the toner is brought to one side of the photoconductor cleaning device 63 by the recovery screw 79, returned to the liquid developing device 61 through a toner recycling device 80 described later, and reused.
Further, the static elimination device 64 is constituted by a static elimination lamp, and irradiates light to initialize the surface potential of the photosensitive drum 20.
[0023]
In the image forming unit 18 having the above configuration, first, the surface of the photosensitive drum 20 is uniformly charged by the charging device 60 as the photosensitive drum 20 rotates. Next, based on the image information read by the scanner 300, the exposure device 21 irradiates writing light L such as a laser or LED to form an electrostatic latent image on the photosensitive drum 20. Thereafter, the electrostatic latent image is visualized by the liquid developing device 61 to form a toner image. This toner image is primarily transferred onto the intermediate transfer belt 10 by the primary transfer device 62. The transfer residual toner remaining on the surface of the photosensitive drum 20 after the primary transfer is removed by the photosensitive member cleaning device 63, and thereafter, the surface of the photosensitive drum 20 is discharged by the static eliminating device 64, and the next image formation is performed. Provided.
[0024]
Next, the operation of the copying machine in this embodiment will be described.
When copying a document using the copying machine having the above configuration, first, the document is set on the document table 30 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed by it. Thereafter, when the user presses a start switch (not shown), when the document is set on the automatic document feeder 400, the document is conveyed onto the contact glass 32. Then, the scanner 300 is driven and the first traveling body 33 and the second traveling body 34 start traveling. Thereby, the light from the first traveling body 33 is reflected by the document on the contact glass 32, and the reflected light is reflected by the mirror of the second traveling body 34 and guided to the reading sensor 36 through the imaging lens 35. . In this way, the image information of the original is read.
[0025]
When the start switch is pressed by the user, a drive motor (not shown) is driven, and one of the support rollers 14, 15, 16 is rotationally driven to rotate the intermediate transfer belt 10. At the same time, the photosensitive drums 20Y, 20C, 20M, 20BK of the image forming units 18Y, 18C, 18M, and 18BK and the secondary transfer belt 24 of the secondary transfer device 22 are also rotationally driven. At this time, the detection marks provided on the back surface of the intermediate transfer belt 10 are detected by a mark sensor (not shown), thereby synchronizing the image forming units. The intermediate transfer belt 10, the photosensitive drums 20Y, 20C, 20M, 20BK and the secondary transfer belt 24 are controlled so that a constant relative speed is maintained among them. Thereafter, based on the image information read by the reading sensor 36 of the scanner 300, the exposure device 21 irradiates the writing light L onto the photosensitive drums 20Y, 20C, 20M, and 20BK of the respective image forming units. As a result, electrostatic latent images are formed on the respective photosensitive drums 20Y, 20C, 20M, and 20BK, and are visualized by the liquid developing devices 61Y, 61C, 61M, and 61BK. Then, yellow, cyan, magenta, and black toner images are formed on the photosensitive drums 20Y, 20C, 20M, and 20BK, respectively. Each color toner image formed in this way is primarily transferred by the primary transfer devices 62Y, 62C, 62M, and 62BK so as to sequentially overlap each other on the intermediate transfer belt 10. As a result, a composite toner image in which the toner images of the respective colors overlap is formed on the intermediate transfer belt 10. The transfer residual toner remaining on the intermediate transfer belt 10 after the secondary transfer is removed by the belt cleaning device 17.
[0026]
When the user presses the start switch, the paper feed roller 42 of the paper feed table 200 according to the transfer paper selected by the user rotates, and the transfer paper is sent out from one of the paper feed cassettes 44. The transferred transfer paper is separated into one sheet by the separation roller 45 and enters the paper feed path 46, and is transported by the transport roller 47 to the paper feed path 48 in the copying machine main body 100. The transfer paper conveyed in this way is stopped when it hits the registration roller 49. When using transfer paper that is not set in the paper feed cassette 44, the transfer paper set in the manual feed tray 51 is sent out by the paper feed roller 50 and separated into one sheet by the separation roller 52, and then the manual paper feed path. It is conveyed through 53. Then, it stops when it hits the registration roller 49.
[0027]
The registration roller 49 rotates in accordance with the timing at which the composite toner image formed on the intermediate transfer belt 10 as described above is conveyed to the secondary transfer unit facing the secondary transfer belt 24 of the secondary transfer device 22. To start. Here, in general, the registration roller 49 is often used while being grounded, but a bias may be applied to remove paper dust from the transfer paper. A DC voltage is used for the applied bias, but an AC voltage having a DC offset component may be used to charge the transfer paper more uniformly. Note that the surface of the transfer paper after passing through the registration roller 49 to which a bias is applied in this way is slightly negatively charged. Therefore, in this case, since the transfer conditions are different from those of the transfer paper to which no bias is applied to the registration rollers 49 during the secondary transfer from the intermediate transfer belt 10 to the transfer paper, it is necessary to appropriately change the transfer conditions.
[0028]
The transfer sheet sent out by the registration roller 49 is sent to a secondary transfer nip formed between the intermediate transfer belt 10 and the secondary transfer belt 24, and is combined on the intermediate transfer belt 10 by the secondary transfer device 22. The toner image is secondarily transferred onto the transfer paper. Here, in the present embodiment, before the secondary transfer, as described later, a fixing liquid is applied to the composite toner image on the intermediate transfer belt 10. The composite toner image to which the fixing liquid is applied is pressed against the transfer paper at the secondary transfer nip, so that the composite toner image is secondarily transferred to the transfer paper and simultaneously fixed onto the transfer paper. Thereafter, the transfer sheet is conveyed to the sheet discharge roller 56 while being attracted to the secondary transfer belt 24, and is discharged and stacked on the sheet discharge tray 57.
[0029]
Next, the fixing process which is a characteristic part of the present invention will be described.
FIG. 1 is a schematic configuration diagram of a portion including a fixing device as fixing means of a copying machine according to the present embodiment.
In the copying machine of the present embodiment, a fixing device 90 is disposed on the upstream side of the secondary transfer portion in the surface movement direction of the intermediate transfer belt 10. The fixing device 90 includes a supply roller 91 as a fixing liquid supply unit disposed so as to face the surface of the intermediate transfer belt 10 with a small gap. The fixing device 90 is configured to be movable by a driving mechanism (not shown) so that the supply roller 91 can approach or separate from the surface of the intermediate transfer belt 10. A fixing liquid 92 is accommodated in the fixing liquid tank 93 of the fixing device 90, and the supply roller 91 is disposed in the fixing liquid 92. The supply roller 91 is rotationally driven in the direction of the arrow in the drawing when the fixing liquid 92 is applied to the toner. As a result, the fixing liquid 92 is pumped up on the surface of the supply roller 91. The fixing liquid 92 pumped up in this way is regulated by the metering blade 94, and the fixing liquid adhering to the surface of the supply roller 91 is adjusted to an appropriate amount. The fixing solution on the supply roller 91 is conveyed to a position facing the surface of the intermediate transfer belt 10 as the supply roller 91 rotates, and supplies the fixing solution to the surface of the intermediate transfer belt 10.
[0030]
Further, when the supply roller 91 is used as a fixing liquid supply unit that supplies the fixing liquid to the toner on the intermediate transfer belt 10, there is a possibility that the toner image carried on the intermediate transfer belt 10 may be disturbed. Therefore, in this embodiment, a supply roller 91 in which a base made of a conductive material is covered with an insulating layer or a high resistance layer is used, and a power source 95 as an electric field forming unit is connected to the supply roller 91. Specifically, for example, a conductive rubber layer formed on a stainless steel core and the surface thereof covered with an insulating PFA tube can be used. With such a configuration, an electric field is formed between the supply roller 91 and the intermediate transfer belt 10 in a direction in which the toner is pressed toward the intermediate transfer belt. By forming such an electric field, the binding force of the toner on the intermediate transfer belt 10 toward the intermediate transfer belt 10 at the liquid supply position can be increased. As a result, the fixing liquid 92 can be supplied to the toner without disturbing the toner image carried on the intermediate transfer belt 10.
[0031]
The fixing liquid 92 used in this embodiment has a material that dissolves or swells the resin component constituting the toner (hereinafter referred to as “dissolving / swelling component”) as a component. Such materials include higher glycol ether, ethylene glycol monoether, diethylene glycol monoether, ethylene glycol, monomethyl ether = 2-methoxyethanol, diethylene glycol, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, ethylene glycol, butyl cellosolve ethyl carbitol. , Aliphatic dibasic acid ester, DBE (dibasic acid ester), ester-based high boiling point admixture, linear dibasic acid ester (maleic acid ester), itaconic acid ester, trimellitic ester, dibasic acid ester, etc. It is done.
[0032]
Here, if the dissolving / swelling component is supplied to the toner in an amount greater than the necessary amount, the toner is excessively dissolved, causing a toner image to flow. The toner on the intermediate transfer belt 10 is desirably in a semi-dissolved state or a swollen state, and depending on the type of the dissolved / swelled component, approximately half or less of the toner is sufficient. The amount of toner constituting the toner image on the intermediate transfer belt 10 is several [μm] level in thickness, and the dissolved / swelled component needs to be further thinned and supplied in a small amount. It is extremely difficult to supply this uniformly. Therefore, as a method for supplying such a small amount of the dissolving / swelling component, a method of diluting the dissolving / swelling component with some liquid is generally used. As this diluting solution, one using water in consideration of the influence on the environment is known. The dissolution / swelling component as described above can be made into an aqueous solution by using a surfactant. Examples of such surfactants include anionic (anionic) surfactants such as fatty acid derivative sulfates, sulfonic acid types, and phosphate esters, cation (cation) such as quaternary ammonium salts, heterocyclic amines, and amine derivatives. Examples include surfactants, amino acid esters, amino acids, zwitterionic (nonionic) surfactants such as sulfobetaine, nonionic surfactants, polyoxyalkylene alkyl ethers, polyoxyethylene alkyl amines, and the like. According to the fixing solution in which the above-described dissolving / swelling component and the surfactant are mixed at a concentration of 20% or less with respect to water, a small amount of the dissolving / swelling component is added to the toner on the intermediate transfer belt 10. Can be supplied.
[0033]
However, the carrier liquid adheres to the toner on the intermediate transfer belt 10 to which the fixing liquid 92 is supplied. Therefore, when water is used as the diluting liquid (main component) of the fixing liquid 92, the carrier liquid (dimethyl silicon, Isoper, etc.) of the liquid developer is generally oil, so that the fixing liquid is repelled by the carrier liquid. End up. As a result, it takes time for the dissolving / swelling component of the fixing solution 92 to reach the toner, and the reaction time between the resin component of the toner and the dissolving / swelling component in the fixing solution is delayed. Further, when water is mixed in the carrier liquid, the insulating property of the carrier liquid is lost, and as a result, the charging characteristics of the toner change, and it is difficult to control the developing electric field and the transfer electric field. Further, after the toner image on the intermediate transfer belt 10 is transferred onto the transfer paper P, if the cleaning by the belt cleaning device 17 is not sufficiently performed, water adheres to the surface of the photosensitive drum 200, and image formation is performed. It can be difficult.
[0034]
Therefore, in the present embodiment, as the diluting liquid for the fixing liquid 92, an insulating liquid used for the carrier liquid of the liquid developer is used. Specifically, the non-volatile dimethyl silicon used as the carrier liquid for the liquid developer is used as the diluting liquid for the fixing liquid 92. Thereby, the dissolving / swelling component of the fixing liquid 92 can quickly reach the toner wrapped in the carrier liquid on the intermediate transfer belt 10. Therefore, the reaction time between the resin component of the toner and the dissolving / swelling component in the fixing solution can be shortened. In addition, as in this embodiment, non-volatile dimethyl silicon is used as a diluting solution and a carrier solution for the fixing solution, so that there is no adverse effect on the environment. In addition, by using a non-volatile liquid as in this embodiment, there is no need to provide a mechanism for recovering volatile components.
Further, as in the present embodiment, the same material as the carrier liquid of the liquid developer is used as the diluent of the fixing liquid 92, so that the charging characteristics of the toner are not changed.
[0035]
Further, the surface of the intermediate transfer belt 10 of the present embodiment is subjected to fluorine treatment or the like as a liquid repellent treatment, thereby imparting liquid repellency. The surface of the intermediate transfer belt 10 subjected to such a liquid repellent function functions as a release layer, and even if the fixing liquid 92 on the supply roller 91 comes into contact with the surface, the fixing liquid 92 remains on the surface of the intermediate transfer belt. It remains on the supply roller 91 without adhering to it. That is, even if the fixing liquid 92 is supplied to the surface of the intermediate transfer belt 10, the fixing liquid 92 hardly adheres to the surface of the intermediate transfer belt 10. As another release layer, for example, a layer coated with a PFA tube or the like can be used. Further, if the intermediate transfer belt 10 is provided with an elastic layer, the intermediate transfer belt 10 can be deformed according to the surface state of the transfer paper P, and can be transferred onto the transfer paper P having various surface states.
[0036]
Next, the flow of the fixing process in this embodiment will be described.
When the color toner images are superimposed on the intermediate transfer belt 10 to form a composite toner image, the composite toner image is moved to a position facing the supply roller 91 of the fixing device 90 as the surface of the intermediate transfer belt 10 moves. Be transported. The fixing device 90 stands by in a state of being separated from the intermediate transfer belt 10 until the synthesized toner image is conveyed. The fixing device 90 moves the supply roller 91 to a position close to the surface of the intermediate transfer belt 10 by the drive mechanism immediately before the leading end of the composite toner image reaches the position facing the supply roller 91. As a result, the fixing liquid 92 on the supply roller 91 is supplied to the surface of the intermediate transfer belt 10.
[0037]
FIG. 5A to FIG. 5D are explanatory views showing changes in the state of the toner T carried on the surface of the intermediate transfer belt 10 and the fixing liquid 92 applied thereto over time.
FIG. 5A shows the state of the toner T, the carrier liquid, and the fixing liquid 92 on the intermediate transfer belt 10 at a facing position (liquid supply position) where the intermediate transfer belt 10 and the supply roller 91 face each other. At this liquid supply position, the space between the intermediate transfer belt 10 and the supply roller 91 is filled with the fixing liquid 92, and the fixing liquid 92 comes into contact with the intermediate transfer belt 10 regardless of the presence or absence of toner adhesion. Then, when the surface portion of the intermediate transfer belt 10 shown in FIG. 5A passes through the liquid supply position, the state shown in FIG. That is, the surface of the intermediate transfer belt 10 on which the toner T is not carried is subjected to the liquid repellent treatment as described above, so that the liquid component of the fixing liquid 92 is repelled. Therefore, the fixing liquid 92 that has been in contact with the surface portion is collected in the fixing device 90 while adhering to the supply roller 91 without adhering to the surface portion. On the other hand, the fixing liquid 92 that has been in contact with the toner T carried on the surface of the intermediate transfer belt 10 intersects with and adheres to the carrier liquid covering the toner T, not on the supply roller 91. Therefore, on the intermediate transfer belt 10 that has passed the liquid supply position, the fixing liquid 92 adheres only to the portion carrying the toner T, and the fixing liquid 92 does not adhere to the surface portion where the toner T is not carried. .
[0038]
When the fixing liquid 92 is applied to the toner T in this way, the resin component of the toner T reacts with the dissolving / swelling component of the fixing liquid 92. As a result, the toner T swells and dissolves as shown in FIG. Thereafter, the toner T becomes sticky, and as shown in FIG. 5D, the excessive portion of the fixing liquid 92 impregnated inside during swelling is discharged to the surface and changes into a film shape. The toner T thus changed into a film shape is transported to the secondary transfer portion where a nip is formed by this and the secondary transfer belt 24 of the secondary transfer device 22 as the surface of the intermediate transfer belt 10 moves. . In the secondary transfer portion, the toner T on the intermediate transfer belt 10 is pressed against the surface of the transfer paper P, so that it is transferred and fixed on the transfer paper P due to its adhesiveness.
[0039]
As described above, according to the present embodiment, since the liquid development method is adopted, even when image formation with the same image area ratio is performed, the amount of toner attached on the intermediate transfer belt 10 can be reduced as compared with the dry development method. . Therefore, the minimum amount of the fixing liquid 92 that can sufficiently dissolve or swell the toner on the intermediate transfer belt 10 can be reduced. As a result, the amount of the fixing liquid 92 applied to the toner can be reduced, and the fixing liquid tank 93 can be downsized. Therefore, the copying machine can be miniaturized.
Further, since the same liquid as the carrier liquid of the liquid developer is used as the diluting liquid of the fixing liquid 92, the dissolving / swelling component in the fixing liquid immediately contacts the toner and reacts with the resin component of the toner. can do. Therefore, the reaction time can be shortened. As a result, the conveyance time from the liquid supply position to the secondary transfer position can be shortened, so that the image forming speed can be improved. Further, since the length of the intermediate transfer belt 10 between the liquid supply position and the secondary transfer portion can be shortened, the copying machine can be further downsized.
[0040]
[Configuration example 1]
Next, another configuration example (hereinafter referred to as “configuration example 1”) of the fixing device of the above-described embodiment will be described.
FIG. 6 is a schematic configuration diagram showing the fixing device 190 of the first configuration example. The fixing device 190 is common to the fixing device 90 of the above embodiment in that the fixing liquid 92 is supplied to the surface of the intermediate transfer belt 10 by the supply roller 191. However, in the fixing device 190 of Configuration Example 1, the method for measuring the amount of the fixing liquid adhering to the surface of the supply roller 191 is different from that in the above embodiment. That is, in the above embodiment, the amount of the fixing liquid on the supply roller 191 is measured by the metering blade 94, whereas in the present configuration example 1, the amount is measured by the application roller 195.
[0041]
FIG. 7 is a front view showing the application roller 195. As shown in the drawing, fine grooves with a uniform pattern are formed on the surface of the application roller 195. The application roller 195 is disposed so as to be in contact with the surface of the supply roller 191 while being immersed in the fixing liquid 92 in the fixing liquid tank 193. The application roller 195 is driven to rotate in the direction of the arrow in the drawing when the fixing liquid 92 is applied to the toner. As a result, the fixing liquid 92 is pumped up on the surface of the application roller 195. The fixer 92 pumped up in this manner is carried in a state where it enters the groove on the surface of the application roller 195, and the fixer 92 adhering to the outside of the groove is scraped off by the scraping blade 194. Then, the fixing liquid 92 on the application roller 195 is conveyed to a contact position with the supply roller 191 as the application roller 195 rotates. At this contact position, the supply roller 191 and the application roller 195 move in the counter direction, and the fixing liquid 92 inside the groove of the application roller 195 adheres to the surface of the supply roller 191. Therefore, the amount of the fixing liquid on the supply roller 191 can be adjusted to an appropriate amount by adjusting the internal volume of the groove provided on the surface of the application roller 195.
[0042]
In the configuration example 1, the grooves formed on the surface of the application roller 195 are grooves extending in a large number of spirals as shown in FIG. 7, but may be grooves formed in other patterns. Good. For example, a groove pattern in which a large number of reverse cone or reverse pyramid holes are uniformly arranged on the surface of the application roller 195 can be adopted.
[0043]
As described above, according to the first configuration example, the fixing liquid 92 can be uniformly applied to the surface of the supply roller 191 with a layer thickness on the order of μm by the groove provided in the application roller 195. Therefore, a very thin layer of the fixing solution 92 can be brought into contact with the surface of the intermediate transfer belt 10, and the amount of the fixing solution 92 supplied to the surface of the intermediate transfer belt 10 can be suppressed to a small amount. As a result, the amount of the fixing liquid 92 entering the transfer paper P can be further reduced, and wasteful consumption of the fixing liquid 92 can be further suppressed. As a result, it is possible to reduce the size of the fixing tank and the size of the copying machine.
[0044]
Further, as in the fixing device 290 shown in FIG. 8, a configuration in which the fixing liquid 92 is supplied in the form of foam to the surface of the intermediate transfer belt 10 may be adopted. Various methods for making the fixer 92 foamy are conceivable. For example, there may be mentioned a method of bubbling by supplying compressed air from a compressor to the fixing liquid 92 containing a surfactant. Further, as a method for producing finer bubbles, there is a method in which the fixing liquid 92 is ejected through a porous filter having a minute diameter hole, for example, a ceramic or sponge-like one. In the case shown in the drawing, the head 291a of the nozzle 291 serving as the fixing liquid supply means is open over the width direction of the intermediate transfer belt 10, and a porous filter (not shown) is disposed inside the head 291a. Then, the fixing liquid 92 in the fixing liquid tank 293 is pumped from the suction pipe 291b of the nozzle 291 by a pump (not shown). The pumped fixer 92 passes through the nozzle 291 and is ejected from the head 291a. The ejected fixing liquid 92 becomes a bubble when passing through the porous filter, and is supplied to the surface of the intermediate transfer belt 10. Here, the head 291a extending in the width direction of the intermediate transfer belt 10 is taken as an example, but a configuration in which a narrow head is reciprocated in the axial direction of the intermediate transfer belt 10 may be used. Note that a surfactant may be included in the fixing liquid 92 in order to efficiently make the fixing liquid 92 foam. In this case, the content ratio of the surfactant is preferably 20% or less. Within this range, it has been confirmed by the inventors' research that there is no change in the fixability of the toner T due to the inclusion of the surfactant. According to such a configuration, the fixing liquid 92 can be supplied in a wide range with a small amount of liquid by supplying the fixing liquid 92 in a foam state. At this time, the foam-like fixing liquid 92 may also adhere to the surface portion of the intermediate transfer belt 10 on which the toner T is not carried. However, since the fixing liquid 92 is easily movable by the liquid-repellent action of the intermediate transfer belt 10, the fixing liquid 92 is finally in the vicinity by receiving the action of vibration and gravity applied to the intermediate transfer belt 10. It is integrated with the fixing liquid 92 adhering to the toner T. By the time the second transfer portion is reached, the fixing liquid is almost removed from the surface portion of the intermediate transfer belt 10 on which the toner T is not carried. Accordingly, the amount of the fixing liquid 92 supplied to the surface of the intermediate transfer belt 10 can be suppressed to a small amount. As a result, the fixing liquid tank 93 can be downsized, and the copying machine can be downsized.
[0045]
Further, as in the fixing device 390 shown in FIG. 9, a configuration in which the fixing liquid 92 is supplied in the form of a mist to the surface of the intermediate transfer belt 10 may be adopted. Various methods for making the fixer 92 mist are conceivable. For example, there is a method that employs a so-called spray method in which compressed air from a compressor is supplied to the fixing liquid 92 through a nozzle and ejected in a mist form. In the case shown in the drawing, the head 391 a of the nozzle 391 serving as the fixing liquid supply means is opened over the width direction of the intermediate transfer belt 10. Then, the fixing liquid 92 in the fixing liquid tank 393 is pumped from the suction pipe 391b of the nozzle 391 by a pump (not shown). The pumped fixing liquid 92 passes through the nozzle 391 and is ejected from the head 391 a in the form of a mist, which is supplied to the surface of the intermediate transfer belt 10. Here, the head 391a extending in the width direction of the intermediate transfer belt 10 is described as an example, but a configuration in which the narrow head 391a is reciprocated in the axial direction of the intermediate transfer belt 10 may be employed. Even with such a configuration, the fixing liquid 92 can be supplied over a wide range with a small amount of liquid.
[0046]
[Configuration example 2]
Next, another configuration example (hereinafter referred to as “configuration example 2”) of the fixing device of the above-described embodiment will be described.
On the intermediate transfer belt 10, the toner T to which the fixing liquid 92 has been applied swells as shown in FIG. 5C, and then the fixing liquid 92 impregnated inside as shown in FIG. 5D. The excess part is discharged to the surface and changes into a film. The fixer 92 remaining after the film is changed is an unnecessary material that no longer contributes to fixing. If the fixing liquid 92 is left as it is and adheres to the transfer paper P, the transfer paper P tends to curl or wrinkle. Therefore, in order to further suppress curling and wrinkling of the transfer paper P, it is desirable to positively remove the unnecessary fixing liquid 92.
Further, when an image having a high image area ratio is formed on the transfer paper P, the occupation ratio of the toner T on the transfer paper P is also increased, and the carrier liquid and the fixing liquid adhering to the transfer paper P in proportion to this. The amount of 92 also increases. In this case, if the supply amount of the fixing liquid 92 to the intermediate transfer belt 10 by the fixing devices 90, 190, 290, and 390 is too large, the degree of curling or wrinkling of the transfer paper P is within a practical range. There is a risk of exceeding. Therefore, from this point, it can be said that it is desirable to positively remove the fixing liquid 92 that is no longer needed.
Therefore, in this configuration example 2, a specific example in which a mechanism for removing this is added will be described.
[0047]
FIG. 10 is a schematic configuration diagram illustrating the fixing device 490 of the second configuration example. The main body portion of the fixing device 490 has the same configuration as that of the fixing device 190 of the configuration example 1 shown in FIG. However, the fixing device 490 is provided with an excess liquid recovery roller 496a as an excess liquid removing unit, unlike the above embodiment and the above configuration example 1. The excess liquid recovery roller 496a is disposed so as to contact the surface of the intermediate transfer belt 10 between the liquid supply position and the secondary transfer portion. The excess liquid recovery roller 496a is configured to be rotationally driven at the same linear speed and in the same direction as the surface of the intermediate transfer belt 10 at the contact position. The surplus liquid recovery roller 496a is preferably a metal roller that has been anodized. In addition, a roller formed of rubber or the like may be used. In this case, the surface is made of an oil repellent material such as silicon rubber as a release layer so that the adhesive toner T is not easily attached. It is desirable that it is formed.
[0048]
In the second configuration example, when the surface portion of the intermediate transfer belt 10 carrying the fixing liquid 92 and the toner T reaches the contact position with the surplus liquid recovery roller 496a, the intermediate transfer belt 10 and the surplus liquid recovery roller 496a are interposed. Then, the fixing solution 92 that is no longer needed is sandwiched. When the surface portion of the intermediate transfer belt 10 passes through the contact position, the fixing liquid 92 on the intermediate transfer belt 10 adheres to the surface side of the excess liquid recovery roller 496a. As a result, the unnecessary fixing liquid 92 is recovered by the excess liquid recovery roller 496 a and removed from the surface of the intermediate transfer belt 10. The fixer 92 recovered by the excess liquid recovery roller 496a is scraped off by the cleaning blade 496b.
[0049]
Further, as in the fixing device 590 shown in FIG. 11, an air knife 596 can be used as the excess liquid removing means. The air knife 596 includes a slit-like air outlet 596 a that opens across the width direction of the intermediate transfer belt 10. The air knife 596 includes an intake fan 596b, and is configured such that the air sucked by the intake fan 596b is ejected from the air outlet 596a. The air outlet 596 a is disposed so as to blow air onto the surface of the intermediate transfer belt 10 in a counter direction with respect to the surface movement direction of the intermediate transfer belt 10. The fixing liquid 92 on the intermediate transfer belt 10 is returned to the direction opposite to the surface moving direction of the intermediate transfer belt 10 by the air from the air outlet 596a, and finally drops downward by gravity, and the air knife 596 is dropped. Is collected in the collection case 596c.
Here, since the portion of the intermediate transfer belt 10 is inclined downward in the vertical direction from the fixing device main body 190 toward the air knife 596, the recovery case 596c is provided in the air knife 596, but this is not provided. It can also be configured. For example, as shown in FIG. 12, the secondary transfer device 122 is disposed vertically above the intermediate transfer drum 2010 as a toner image carrier. By arranging the fixing device main body 190 and the air knife 596 as shown in the figure, the intermediate transfer belt 10 can be configured to incline upward in the vertical direction from the fixing device main body 190 toward the air knife 596. In this configuration, the unnecessary fixing liquid 92 can be returned to the liquid supply position by air from the air outlet 596a, and the fixing liquid 92 can be collected in the fixing device main body 190.
[0050]
As described above, various means for removing the excess liquid are conceivable, but in any of the cases described above, the toner image carried on the intermediate transfer belt 10 may be disturbed. Therefore, in this configuration example 2, the surplus liquid recovery roller 496a in which the base made of a conductive material is covered with an insulating layer or a high resistance layer is used, and a power source 496d as an electric field forming unit is connected to the surplus liquid recovery roller 496a. ing. Specifically, for example, a metal roller that is anodized on the surface of an aluminum alloy roller or an elastic roller having an elastic layer of conductive urethane rubber covered with an insulating PFA tube may be used. it can. With such a configuration, an electric field is formed between the supply roller 91 and the intermediate transfer belt 10 in a direction in which the toner is pressed toward the intermediate transfer belt. By forming such an electric field, the binding force of the toner on the intermediate transfer belt 10 toward the intermediate transfer belt 10 at the liquid removal position can be increased. Thereby, the excess liquid can be removed without disturbing the toner image carried on the intermediate transfer belt 10.
[0051]
As described above, according to the second configuration example, before the toner T on the intermediate transfer belt 10 is secondarily transferred onto the transfer paper P, it is possible to remove the fixing liquid 92 that is no longer necessary for fixing. Thereby, the amount of the fixing liquid 92 attached to the transfer paper P can be suppressed to a small amount. Therefore, the amount of the fixing liquid 92 that enters the transfer paper P is further reduced, and curling and wrinkling of the transfer paper P can be suppressed.
Further, the surface of the intermediate transfer belt 10 has been subjected to liquid repellency treatment as described above, but the liquid repellency may sometimes deteriorate over time. In this case, the fixing liquid 92 may slightly adhere to the surface portion of the intermediate transfer belt 10 on which no toner is carried. However, according to the second configuration example, such a water droplet-like fixing liquid 92 can be similarly recovered by the surplus liquid recovery roller 496a. Therefore, according to the second configuration example, curling and wrinkling of the transfer paper P that can occur due to deterioration of the liquid repellency of the intermediate transfer belt 10 with time can be effectively suppressed.
[0052]
Note that the toner T to which the fixing liquid 92 is applied on the intermediate transfer belt 10 reacts with the fixing liquid 92 to be changed into a film shape as shown in FIG. become. It is known that this reaction is promoted by applying heat. Therefore, a heater 697 as a heating unit may be provided as in the fixing device 690 shown in FIG. The heater 697 is disposed so as to face the surface of the intermediate transfer belt 10 between the liquid supply position and the secondary transfer portion. In this way, by heating the fixing liquid 92 attached to the toner T by the heater 697, the dissolution reaction of the resin component of the toner T is promoted, and the fixing property of the toner T can be improved. In addition, since the transport time from the liquid supply position to the secondary transfer position can be shortened, the image forming speed can be improved. In addition, since the length of the intermediate transfer belt 10 between the liquid supply position and the secondary transfer portion can be shortened, the apparatus can be downsized. Further, by heating with the heater 697 in this way, it is possible to evaporate excess liquid component of the fixing liquid adhering to the toner T, and to further suppress the amount of the fixing liquid 92 adhering to the transfer paper P. it can. Therefore, curling and wrinkling of the transfer paper P can be suppressed.
The heater 697 may be added to the fixing devices 490 and 590 of the configuration example 2. In this case, it is desirable that the heater 697 be disposed on the downstream side of the surface transfer direction of the intermediate transfer belt 10 with respect to the excess liquid removing means such as the excess liquid recovery roller 496a or the air knife 596. In this case, since heat can be applied in a state where the excess liquid is sufficiently removed by the excess liquid removing means, the heat is easily transmitted to the fixing liquid 92 and the toner T. As a result, the dissolution reaction of the resin component of the toner T can be promoted more efficiently, and the amount of the fixing liquid 92 attached to the transfer paper P can be further reduced. Of course, the intermediate transfer belt 10 may be disposed upstream of the surface movement direction.
Further, other configurations may be employed instead of the heater 697. For example, together with the heater 697, a hot air supply device as a hot air supply unit including a fan for blowing hot air onto the surface of the intermediate transfer belt 10 to which the toner T and the fixing liquid 92 are attached can be used. In this case, the toner T and the fixing liquid 92 on the intermediate transfer belt 10 can be heated more efficiently than in the case where only the heater 697 is used. In particular, as shown in FIG. 14, if the fixing device 790 has a heater 797 disposed inside the surplus liquid recovery roller 496a, a means having both functions of the surplus liquid removing means and the heating means can be realized. . As a result, the space of the apparatus can be saved.
Further, instead of the heater 697, a heating means as shown in FIG. 15 may be employed. This heating means is a heating roller 797 that contacts the back surface of the intermediate transfer belt 10. The heating roller 897 includes a heater 897a therein, and heats the intermediate transfer belt 10 from the back side. When the intermediate transfer belt 10 is heated by the heating roller 897, the toner T and the fixing liquid 92 adhering to the surface thereof are heated. According to this configuration, the number of members arranged around the intermediate transfer belt 10 can be reduced, and the apparatus can be downsized.
[0053]
As described above, in the copying machine of the above embodiment, the toner image obtained by developing the latent image on the photosensitive drum 20 as the latent image carrier is transferred to the intermediate transfer member by the primary transfer device 62 as the first transfer unit. Is transferred onto the intermediate transfer belt 10. Then, the toner image transferred onto the intermediate transfer belt 10 is transferred onto the transfer paper P as the recording material by the secondary transfer device 22 as the second transfer means. Further, the copying machine applies a fixing solution that dissolves or swells the toner to the toner, and fixes the toner onto the transfer paper P as fixing devices 90, 190, 290, 390, 490, 590, 690 and 790 are provided. This fixing device applies a fixing liquid 92 to the toner carried on the surface of the intermediate transfer belt before transferring the toner image on the intermediate transfer belt 10 onto the transfer paper P. Here, in the present copying machine, as a developing unit that develops the latent image on the photosensitive drum 20, a liquid developing device 61 that is a liquid developing unit that performs development with a liquid developer in which toner is dispersed in a carrier liquid is used. Yes. Thereby, even when image formation with the same image area ratio is performed, the amount of toner adhering to the intermediate transfer belt 10 can be reduced as compared with the dry development method. Therefore, the minimum amount of the fixing liquid 92 that can sufficiently dissolve or swell the toner on the intermediate transfer belt 10 can be reduced. As a result, the amount of the fixing liquid 92 applied to the toner can be reduced, and the fixing liquid tanks 93, 193, 293, 393 can be reduced in size, and the copying machine can be reduced in size.
Further, the fixing liquid 92 of the present embodiment contains a diluting liquid that is a liquid component that easily mixes with the carrier liquid. By using such a diluting solution, the dissolving / swelling component in the fixing solution can quickly come into contact with the toner and react with the resin component of the toner. Therefore, the reaction time can be shortened. As a result, the conveyance time from the liquid supply position to the secondary transfer position can be shortened, so that the image forming speed can be improved. In addition, since the length of the intermediate transfer belt 10 between the liquid supply position and the secondary transfer portion can be shortened, the apparatus can be downsized.
In particular, in the fixing liquid 92 of the present embodiment, if the same material as the carrier liquid is used for the diluting liquid, the reaction time between the dissolving / swelling component in the fixing liquid and the resin component of the toner can be further shortened. Further, if the liquid component of the fixing liquid is a substance having a small electrical resistance such as water, it adheres to the photosensitive drum 20 from the intermediate transfer belt 10 and remains on the photosensitive drum 20 to charge the toner. The photosensitive drum 20 may be adversely affected and image formation itself may be difficult. However, if the same material as the carrier liquid is used for the diluting solution of the fixing solution as in this embodiment, stable image formation can be performed without such adverse effects.
In this embodiment, the intermediate transfer belt 10 is provided with a surface layer that has been subjected to fluorine treatment, which is a release layer. As a result, the fixing liquid 92 hardly adheres to the surface of the intermediate transfer belt 10, and the fixing liquid 92 can be attached only to the toner. Thereby, after the toner is transferred onto the transfer paper P, the amount of the fixing liquid adhering to the transfer paper P can be reduced as compared with the conventional one in which the fixing liquid is applied to the entire transfer paper. it can. Therefore, it is possible to reduce the amount of the fixing liquid that enters the transfer paper P, and it is possible to reduce the size of the fixing liquid tanks 93, 193, 293, and 393, thereby reducing the size of the copying machine. Further, since the releasability of the intermediate transfer belt 10 is enhanced, the toner is easily separated from the intermediate transfer belt 10 during the secondary transfer from the intermediate transfer belt 10 to the transfer paper P. As a result, the transfer rate during secondary transfer can be increased.
The fixing device 90 of the present embodiment includes a supply roller 91 that is disposed so as to be in contact with the surface of the intermediate transfer belt or to be opposed to the surface of the intermediate transfer belt with a predetermined interval. Yes. The supply roller 91 applies the fixing liquid 92 to the toner on the intermediate transfer belt 10. Accordingly, a necessary and sufficient amount of the fixing liquid 92 can be applied to the toner on the intermediate transfer belt 10 with a simple mechanism.
In particular, in this embodiment, when the fixing liquid 92 is supplied by the supply roller 91, a power source 95 is provided as an electric field forming unit that forms an electric field in a direction in which the toner carried on the surface of the intermediate transfer belt is pressed against the intermediate transfer belt. ing. By forming such an electric field, the binding force of the toner on the intermediate transfer belt 10 toward the intermediate transfer belt 10 at the liquid supply position can be increased. As a result, the fixing liquid 92 can be supplied to the toner without disturbing the toner image carried on the intermediate transfer belt 10.
The fixing device of Configuration Example 2 in the above embodiment is disposed so as to be in contact with the surface of the intermediate transfer belt or to face the surface of the intermediate transfer belt with a predetermined gap therebetween. There is provided a recovery roller 496a for recovery, and before transferring the toner image on the intermediate transfer belt onto the transfer paper P, there is provided an excess liquid removing means for adhering and removing the excess to the surface of the recovery roller 496a. Yes. A release layer is formed on the surface of the collection roller 496a. Thereby, it is possible to prevent the toner constituting the toner image from adhering to the surface of the recovery roller 496a when the excess amount of the fixing liquid is recovered. Therefore, the toner image on the intermediate transfer belt 10 can be prevented from being disturbed by the collecting operation by the collecting roller 496a.
Further, in the configuration example 2 in the above-described embodiment, as described above, before the toner image on the intermediate transfer belt 10 is transferred onto the transfer paper P, an excess amount of the fixing liquid 92 supplied to the surface of the intermediate transfer belt. A recovery roller 496a or the like is provided as surplus liquid removing means for removing water. A power supply 496d is provided as an electric field forming means for forming an electric field in a direction in which the toner carried on the surface of the intermediate transfer belt is pressed against the intermediate transfer belt when removing the surplus. By forming such an electric field, the binding force of the toner on the intermediate transfer belt 10 toward the intermediate transfer belt 10 at the liquid removal position can be increased. As a result, it is possible to remove the surplus of the fixing liquid without disturbing the toner image carried on the intermediate transfer belt 10.
[0054]
In this embodiment, the color copying machine using the intermediate transfer member has been described as an example. However, the present invention is not limited to this, and various modifications can be made. For example, instead of the intermediate transfer belt 10, a drum-shaped or roller-shaped intermediate transfer member may be used. Further, a so-called one-drum type image forming apparatus may be used in which each color toner image is sequentially formed on a single latent image carrier, and these are sequentially transferred onto an intermediate transfer member to form a color image. Needless to say, the image forming apparatus is not limited to a copying machine, but may be a printer or a facsimile.
[0055]
【The invention's effect】
  BookAccording to the present invention, it is possible to reduce the amount of the fixing liquid applied to the toner on the intermediate transfer member. Therefore, it is possible to reduce the size of the image forming apparatus by reducing the size of the fixing liquid tank. There is an excellent effect.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a portion including a fixing device of a copying machine according to an embodiment.
FIG. 2 is a schematic configuration diagram of the entire copier.
FIG. 3 is an enlarged view showing a configuration of a main body portion of the copier.
FIG. 4 is an enlarged view showing a configuration of two adjacent image forming units of the copier.
FIGS. 5A to 5D are explanatory diagrams showing changes in the state of the toner carried on the surface of the intermediate transfer belt and the fixing solution applied thereto over time. FIG.
FIG. 6 is a schematic configuration diagram illustrating a fixing device according to Configuration Example 1;
FIG. 7 is a front view showing an application roller of the identification apparatus.
FIG. 8 is a schematic configuration diagram showing another example of the fixing liquid supply unit of the identification apparatus.
FIG. 9 is a schematic configuration diagram showing still another example of the fixing liquid supply unit of the identification fixing device.
FIG. 10 is a schematic configuration diagram illustrating a fixing device according to Configuration Example 2;
FIG. 11 is a schematic configuration diagram showing another example of surplus liquid removing means of the identification apparatus.
FIG. 12 is a schematic configuration diagram showing another arrangement example of the identification wearing apparatus.
FIG. 13 is a schematic configuration diagram illustrating an example of a fixing device including a heating unit for heating the fixing liquid and the toner.
FIG. 14 is a schematic configuration diagram showing another configuration of the identification wearing apparatus.
FIG. 15 is a schematic configuration diagram showing still another configuration of the identification wearing apparatus.
[Explanation of symbols]
10 Intermediate transfer belt
14, 15, 16 Support roller
18Y, 18C, 18M, 18BK Image forming unit
20Y, 20C, 20M, 20BK Photosensitive drum
21 Exposure equipment
22 Secondary transfer device
61 Liquid developing device
90, 190, 290, 390, 490, 590, 690, 790 Fixing device
91,191 Supply roller
92 Fixer
93,193,293,393 Fixing liquid tank
94 Metering blade
110 Intermediate transfer drum
122 Secondary transfer device
194 scraping blade
195 Application roller
291 391 nozzles
291a, 391a Head
291b, 391b Suction tube
300 scanner
496a Surplus liquid recovery roller
496b Cleaning blade
596 Air knife
596a Air outlet
596b Intake fan
596c Collection case
697, 797, 897a Heater
897 Heating roller
P transfer paper
T Toner

Claims (5)

  1. A latent image carrier;
    Developing means for developing a latent image on the latent image carrier;
    First transfer means for transferring a toner image on the latent image carrier formed by the developing means onto an intermediate transfer body;
    A second transfer unit that transfers the toner image transferred onto the intermediate transfer member onto the recording material, and a fixing solution that dissolves or swells the toner is applied to the toner to fix the toner on the recording material. In an image forming apparatus comprising a fixing unit
    As the developing means, a liquid developing means for developing with a liquid developer in which toner is dispersed in a carrier liquid is used.
    The fixing unit has a supply roller that is in contact with the surface of the intermediate transfer member or is opposed to the surface of the intermediate transfer member with a predetermined interval, and supplies the fixing liquid to the surface of the intermediate transfer member. , the toner image on the intermediate transfer member prior to transfer onto the recording material, which imparts the fixing liquid to the toner carried by the intermediate transfer member surface,
    An image forming apparatus, comprising: an electric field forming unit configured to form an electric field in a direction in which the toner carried on the surface of the intermediate transfer member is pressed against the intermediate transfer member when the fixing solution is supplied by the supply roller .
  2. The image forming apparatus Motomeko 1,
    The image forming apparatus, wherein the liquid component is the same substance as the carrier liquid.
  3. The image forming apparatus according to claim 1 or 2,
    Said as an intermediate transfer member, the image forming apparatus characterized by using a material having a release layer on its surface.
  4. The image forming apparatus according to any one of Motomeko 1 to 3,
    A recovery roller arranged to contact the intermediate transfer member surface or to face the intermediate transfer member with a predetermined gap, and to recover an excess of the fixing solution supplied to the intermediate transfer member surface; Before transferring the toner image onto the recording material, there is provided an excess liquid removing means for removing the excess by adhering to the surface of the collecting roller,
    An image forming apparatus characterized in that a roller having a release layer on its surface is used as the collecting roller.
  5. The image forming apparatus according to any one of claims 1 to 4, wherein:
    Before transferring the toner image on the intermediate transfer body onto the recording material, an excess liquid removing means is provided for removing the excess of the fixing liquid supplied to the surface of the intermediate transfer body,
    An image forming apparatus comprising: an electric field forming unit configured to form an electric field in a direction in which the toner carried on the surface of the intermediate transfer member is pressed against the intermediate transfer member when the excess liquid is removed by the excess liquid removing unit. apparatus.
JP2002274611A 2002-09-20 2002-09-20 Image forming apparatus Expired - Fee Related JP4185742B2 (en)

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US7713622B2 (en) 2004-11-02 2010-05-11 Ricoh Company, Ltd. Fixing solution, capsule structure, fixing method, fixing device and image forming apparatus
JP4413818B2 (en) 2005-05-20 2010-02-10 株式会社リコー Fixing device for fixing liquid and toner
JP4875861B2 (en) * 2005-07-06 2012-02-15 株式会社リコー Fixing device for fixing liquid and toner
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JP4668032B2 (en) * 2005-10-27 2011-04-13 株式会社リコー Fixing apparatus and image forming apparatus
DE602006016702D1 (en) 2005-10-27 2010-10-21 Ricoh Kk Fixing device for a non-heating fixing system
JP4960630B2 (en) 2005-12-28 2012-06-27 株式会社リコー Fixing liquid, toner fixing method, toner fixing device, image forming method, and image forming apparatus
JP4302700B2 (en) * 2006-02-16 2009-07-29 株式会社リコー Fixing apparatus and image forming apparatus
JP4531717B2 (en) * 2006-04-17 2010-08-25 株式会社リコー Fixing liquid, fixing method, fixing device, image forming method, and image forming apparatus
JP4410226B2 (en) 2006-08-31 2010-02-03 株式会社リコー Fixing apparatus and image forming apparatus
JP4276269B2 (en) 2007-02-09 2009-06-10 株式会社リコー Fixing apparatus and image forming apparatus
JP4948290B2 (en) 2007-06-29 2012-06-06 株式会社リコー Fixing device
JP4795379B2 (en) 2008-04-10 2011-10-19 株式会社リコー Fixing liquid, fixing method, fixing device, image forming method, and image forming apparatus
JP2009300686A (en) * 2008-06-12 2009-12-24 Ricoh Co Ltd Image forming apparatus and image forming method
JP5224176B2 (en) * 2008-06-12 2013-07-03 株式会社リコー Image forming apparatus
JP5201065B2 (en) 2008-11-18 2013-06-05 株式会社リコー Fixing solution, fixing method, image forming method, fixing device, and image forming apparatus
JP5054071B2 (en) 2009-02-13 2012-10-24 株式会社リコー Fixing apparatus, image forming apparatus, and fixing solution storage container
JP2011034048A (en) 2009-07-09 2011-02-17 Ricoh Co Ltd Cleaning device, fixing device, and image forming apparatus
JP2012098423A (en) * 2010-10-29 2012-05-24 Ricoh Co Ltd Image forming device and image forming method

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US8428503B2 (en) 2010-03-04 2013-04-23 Ricoh Company, Ltd. Fixing device and image forming apparatus

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