JP2010256606A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which performs energy-saving fixing by efficiently configuring a heating means and cooling means used in fixing and by thermally efficiently achieving satisfactory fixing quality with a simple configuration regardless of whether a development system is of a dry system or wet system. <P>SOLUTION: The image forming apparatus having a non-contact heating means as a fixing means for fixing paper with a toner image formed thereon, includes: a paper conveying means disposed opposite the non-contact heating means; a cooling means for contacting and cooling the paper conveying means; a first air moving means for supplying air for cooling the cooling means; and a second air moving means supplying exhaust, thermally absorbed by the cooling means, to a heating area around the non-contact heating means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a non-contact heating unit as a fixing unit for fixing a toner image formed on a recording medium.

  2. Description of the Related Art An electrophotographic image forming apparatus that forms an electrostatic latent image on a photoreceptor (photosensitive drum), develops it with toner, and transfers and fixes the toner image onto a recording medium such as paper is widely used. .

  As a developing method for developing an electrostatic latent image using a dry developer, a one-component developing method using only a toner and a two-component developing method using a toner and a carrier are known.

  The one-component development method is generally advantageous in terms of simplification, miniaturization, and cost reduction of the apparatus, but the life of the development apparatus is short. The two-component development method is advantageous for long life, but has problems such as generation of magnetic brush marks on the developed image.

  In recent years, a wet development method using a liquid developer having a small toner particle diameter and hardly disturbing a toner image has been used.

  As the liquid developer, it is common to use a liquid developer in which a toner is dispersed at a high concentration in a “carrier liquid” as a solvent.

  The method of developing the latent image on the photoconductor differs between a dry development method using a one-component developer or a two-component developer and a wet development method using a liquid developer, but both are developed on the photoconductor by development. A toner image as an image is formed.

  This toner image is transferred to a recording medium. Alternatively, the toner image is first temporarily transferred to an intermediate transfer member or the like and then secondarily transferred to a recording medium.

  The toner image transferred to the recording medium is fixed on the recording medium, which is usually paper, by being pressurized and heated by a fixing device.

  As a general fixing unit, a heating and pressing unit that uses a heated roller or the like to sandwich a recording medium and pressurizes the nip portion while heating the recording medium has been used, such as a roller fixing unit.

  However, the fixing of the toner image requires a great amount of heat energy for fusing the toner, and it is necessary to appropriately control the fixing temperature in order to ensure the fixing quality.

  In particular, in the case of a toner image developed using a liquid developer, a solvent (hereinafter also referred to as a carrier liquid) is contained between the toner of the toner image and between the toner paper, and the fixing is usually performed only by fusing the toner. More energy input is required.

  In addition, the carrier liquid may cause problems such as a decrease in toner image fixability, crushing or distortion of the image during pressure fixing, or acceleration of back surface in which the toner image on the surface can be seen through on the back surface.

  In general, in order to supply a large amount of heat energy by the heating and pressurizing means, more heat energy can be added by expanding the nip, but the fixing device tends to be large. Also, if the nip time is lengthened, there may be a problem with high temperature offset and separability.

  For this reason, in order to avoid contact pressure at the nip, and in particular in the case of liquid development, to efficiently promote the volatilization of the carrier liquid, a heat source such as a heater is disposed at a position not in contact with the recording medium. However, non-contact heating means for heating and fixing with radiant heat or the like is increasingly used.

  In the case of liquid development, as described above, the presence of the carrier liquid that has permeated into the sheet has a problem that the transparency (backward movement) of the front toner image viewed from the back of the sheet is accelerated. In order to reduce the amount of carrier liquid that has penetrated into the paper, it must be volatilized mainly.

  In this respect, non-contact heating is advantageous from the viewpoint of securing the heating time.

  However, when a non-contact heating unit is used, a sheet conveying unit is necessary for cut paper. Usually, a sheet conveying means (such as a belt) that holds and conveys a sheet is disposed at a position facing the non-contact heating means (for example, see Patent Document 1).

  Japanese Patent Application Laid-Open No. 2004-228561 proposes a technique in which a sheet conveying belt is disposed as a sheet conveying unit, a suction fan is provided below the belt, and the sheet is sucked and conveyed.

  However, in this case, at least between the sheets to be conveyed, the surface supporting the sheet of the sheet conveying means is directly heated. Accordingly, problems arise in heat resistance and double-sided printing.

  For example, in the case of double-sided printing, the surface of the portion where the paper transport unit directly contacts the paper is kept at about 100 ° C. or less in consideration of the influence on the already printed image (first surface) when the paper is transported. There is a need. In other words, it becomes necessary to cool the sheet conveying means (see, for example, Patent Document 2).

  Japanese Patent Application Laid-Open No. H10-228561 proposes a technique for cooling a guide at the lower part of a sheet to be fixed with a heat exhaust fan.

JP 59-91468 A JP-A-4-155370

  As described above, the fixing unit needs to generate a large amount of heat, and in the case of liquid development, it is also necessary to volatilize the carrier liquid from the paper, and a non-contact heating unit has been used.

  However, in this case, as in the technique disclosed in Patent Document 1, it is necessary to dispose paper conveying means (such as a belt) that holds and conveys paper at a position facing the non-contact heating means, and the surface that supports the paper Will be heated directly. Accordingly, problems arise in heat resistance and double-sided printing.

  In order to cope with this problem, it is necessary to provide a cooling fan or the like as in the technique disclosed in Patent Document 2, but on the other hand, this maintains the internal atmospheric temperature of the opposed non-contact heating means. It will interfere.

  In particular, in the case of liquid development, it is necessary to raise the temperature of the paper in order to volatilize the carrier liquid. Therefore, it is advantageous in terms of energy not only to radiate heat by the non-contact heating means but also to keep the internal atmosphere temperature high.

  However, if the internal atmosphere of the non-contact heating means is filled with the vaporized carrier liquid vapor, it will hinder the new volatilization of the carrier liquid from the paper, and the heated air must be replaced.

  As described above, for the fixing by the non-contact heating means, it is difficult to form a structure that sufficiently satisfies the requirements such as a portion requiring temperature rise and a portion requiring cooling, and as a result, it cannot be said that the heat efficiency is good. Therefore, a configuration that brings about further energy saving is desired.

  The present invention has been made in view of the above technical problems. The object of the present invention is to efficiently configure the heating means and cooling means in fixing, regardless of the dry or wet development method, sufficient fixing quality can be realized with a simple structure, heat efficiency, and energy-saving fixing. An image forming apparatus is provided.

  In order to solve the above problems, the present invention has the following features.

1. As fixing means for fixing the toner image formed on the recording medium,
An image forming apparatus having non-contact heating means for heating the recording medium by heat radiation from a non-contact heat source,
A paper conveying means arranged opposite to the non-contact heating means and conveying the recording medium;
A cooling means that abuts on the paper conveying means and cools the paper conveying means;
First air moving means for supplying air for cooling the cooling means to the cooling means;
An image forming apparatus, comprising: a second air moving unit that supplies exhaust gas that has absorbed heat from the cooling unit to a region where air around the non-contact heating unit is heated.

2. The non-contact heating means includes
The non-contact heat source;
A heat insulating cover that encloses the heat source and is opened toward the paper conveying means,
The image forming apparatus according to 1, wherein the second air moving unit supplies air into a heat insulating cover of the non-contact heating unit.

3. The paper conveying means is
A conveyor belt;
3. The image forming apparatus according to 1 or 2, further comprising: a driving unit that drives the conveyance belt.

4). The image forming apparatus according to (3), wherein the driving unit is the cooling unit and cools the driving belt while driving.

5). The image forming apparatus according to any one of 1 to 4, wherein the toner image on the recording medium is developed using a liquid developer.

  According to the image forming apparatus of the present invention, in the image forming apparatus having the non-contact heating unit as the fixing unit for fixing the paper on which the toner image is formed, the paper disposed opposite to the non-contact heating unit. A conveying unit and a cooling unit for contacting and cooling the sheet conveying unit; and a first air moving unit for supplying air for cooling to the cooling unit. It has the 2nd air movement means supplied to the heating area | region around a non-contact heating means. Thereby, it is possible to obtain a sufficient fixing quality with a simple structure, heat efficiency, energy saving.

FIG. 3 is a cross-sectional view illustrating a schematic configuration example of a toner image forming unit, a transfer device, and a fixing device in a wet image forming apparatus. 1A and 1B are a schematic diagram illustrating a schematic configuration related to fixing in an image forming apparatus according to a first embodiment, and FIG. 3A is a front view, and FIG. It is the schematic diagram (a) (front view) which showed schematic structure with another flow path form, and the schematic diagram (b) (perspective view) which showed schematic structure with another flow path form. 4A and 4B are a schematic diagram illustrating a schematic configuration related to fixing in the image forming apparatus according to the second embodiment, and FIG. 5A is a front view, and FIG. FIG. 10 is a schematic diagram illustrating a schematic configuration related to fixing in an image forming apparatus according to a third embodiment, (a) (front view), and (b) (perspective view).

  An image forming apparatus according to an embodiment of the invention will be described with reference to the drawings.

  An image forming apparatus according to the following embodiment will be described by taking the case of a liquid developing method as an example. The present invention is not particularly related to the development method, but is particularly effective in the case of fixing a toner image formed by liquid development.

  Liquid development using a liquid developer is used in image forming apparatuses such as copying machines, simple printing machines, and printers. In general, an electrophotographic image forming process is commonly used for these. First, the electrophotographic wet image forming unit will be described with reference to FIG. 1, and a fixing device that heats and fixes a pre-fixed toner image that has been developed using a liquid developer and transferred to a recording medium. The configuration and functional operation will be described.

(Configuration of image forming unit and functional operation)
An example of the configuration and operation of the toner image forming unit in the image forming apparatus of this embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating a schematic configuration example of a toner image forming unit, a transfer device, and a fixing device in a wet image forming apparatus.

  In FIG. 1, reference numeral 1 denotes a photosensitive drum, which functions as an image carrier. The toner image forming unit 10 has a charging device 2 for uniformly charging the surface of the photosensitive drum 1 disposed around the photosensitive drum 1, and an LED or a laser beam on the charged photosensitive drum 1. , An exposure device 3 for forming an electrostatic latent image, a liquid developing device 4 for developing the electrostatic latent image using a liquid developer, an intermediate transfer member 5 to which the developed toner image is transferred, and A cleaning device 6 for removing the liquid developer remaining on the surface of the photosensitive drum 1 after transfer is provided.

  In general, the liquid developing device 4 carries a thin layer of a liquid developer on its surface, a developing roller 41 for developing a latent image on the photosensitive drum 1 as an image carrier, and a liquid developer 8 on its surface. Developer tank 44 and the like.

  In some cases, before and after the liquid developing device 4, a device for applying or collecting a part of the liquid developer in advance is provided. Here, a squeeze device 61 for removing excess liquid developer from the developed toner image is provided after the liquid developing device 4.

  The developed toner image on the photosensitive drum 1 may be transferred directly to the recording medium 7 such as a recording sheet instead of the intermediate transfer member 5. In the present embodiment, the toner image primarily transferred to the intermediate transfer member 5 is transferred to the recording medium 7 again (secondary transfer) using the transfer roller 51. Normal paper is used as the recording medium 7, and in the following description, the recording medium 7 is assumed to be paper (hereinafter referred to as paper 7).

  In FIG. 1, only one set of the toner image forming unit 10 is arranged, but a plurality of sets (normally four color sets of yellow, magenta, cyan, and black) are provided around the intermediate transfer body 5 for color image formation. ) May be arranged. The color development method, the presence / absence of intermediate transfer, and the like may be set arbitrarily, and an arbitrary arrangement according to it can be taken.

  The photosensitive drum 1 rotates in the direction of arrow A shown in FIG. 1, and the charging device 2 charges the surface of the rotating photosensitive drum 1 to about several hundred volts by corona discharge or the like. On the downstream side of the charging device 2 in the rotation direction of the photosensitive drum, an electrostatic latent image whose surface potential is lowered to about 100 V or less is formed by the laser beam emitted from the exposure device 3.

  A liquid developing device 4 is disposed further downstream of the exposure device 3, and the electrostatic latent image formed on the photosensitive drum 1 is developed using the liquid developer 8.

  In the liquid developing device 4, a liquid developer 8 in which toner is dispersed in an insulating solvent (hereinafter also referred to as carrier liquid) is accommodated in a developer tank 44, and the liquid developer is provided on the surface of the developing roller 41. 8 is supplied, and a thin layer of the liquid developer 8 is carried on the developing roller 41.

  Further, due to the potential difference between the developing roller 41 and the electrostatic latent image on the photosensitive drum 1, the toner particles in the thin layer of the liquid developer 8 carried on the developing roller 41 become an electrostatic latent image on the photosensitive drum 1. Moving, the electrostatic latent image is developed.

  The developed toner image on the photosensitive drum 1 contains a liquid developer 8, that is, toner and carrier liquid. The squeeze device 61 is, for example, a squeeze roller, and removes excess carrier liquid from the developed toner image. The carrier liquid on the squeeze roller is removed by the blade 62.

  The intermediate transfer member 5 rotates in the direction of arrow B shown in FIG. 1 and is applied with a bias voltage at the nip portion with the photosensitive drum 1 that similarly rotates in contact with the intermediate transfer member 5, thereby developing the developed toner on the photosensitive drum 1. The image is primarily transferred onto the intermediate transfer member 5.

  When a plurality of sets of toner image forming units 10 are arranged around the intermediate transfer member 5 for color image formation, the toner images of the respective colors developed in the toner image forming units are superimposed on the intermediate transfer member 5. In each case, primary transfer is performed.

  In the toner image forming unit 10, a cleaning device 6 (for example, a cleaner blade) that removes the liquid developer 8 remaining on the surface of the photosensitive drum 1 after the primary transfer is disposed on the downstream side of the intermediate transfer member 5. ing. The cleaning device 6 removes the liquid developer 8 remaining on the photosensitive drum 1.

  The toner image primarily transferred onto the intermediate transfer member 5 is sandwiched between a sheet 7 conveyed at the same speed as the peripheral speed of the intermediate transfer member 5 in the direction of arrow C in FIG. By applying a voltage, the image is secondarily transferred onto the sheet 7.

  The sheet 7 on which the toner image is transferred by the transfer roller 51 is conveyed to the fixing device 9 and is discharged after being heated and fixed.

  Details of the heating means of the toner image at the time of fixing and the volatilization and fixing of the carrier liquid thereby will be described later.

(Developer composition)
The liquid developer 8 used for development will be described. In the liquid developer 8, colored toner particles are dispersed at a high concentration in a carrier liquid as a solvent. In addition, additives such as a dispersant and a charge control agent may be appropriately selected and added to the liquid developer 8.

  Any carrier liquid can be used without particular limitation as long as it is generally used as an electrophotographic developer. In consideration of safety, an insulating, non-volatile solvent at room temperature is used. Examples of the non-volatile solvent include silicon oil, mineral oil, paraffin oil, mineral oil, and the like.

  The toner particles are mainly composed of a resin and a pigment or dye for coloring. The resin has a function of uniformly dispersing pigments and dyes in the resin and a function as a binder when being fixed to the recording material.

  Examples of the resin that can be used include thermoplastic resins such as polystyrene resin, styrene-acrylic resin, acrylic resin, polyester resin, epoxy resin, polyamide resin, polyimide resin, and polyurethane resin. A plurality of these resins may be mixed and used.

  Commonly commercially available pigments and dyes used for coloring the toner can also be used. For example, carbon black, bengara, titanium oxide, silica, phthalocyanine blue, phthalocyanine green, sky blue, benzidine yellow, lake red D, etc. can be used as the pigment. Solvent red 27, acid blue 9, or the like can be used as the dye.

  As a method for adjusting the liquid developer, it can be adjusted based on a commonly used technique. For example, the resin and the pigment are melt kneaded using a pressure kneader, a roll mill or the like at a predetermined blending ratio and uniformly dispersed, and the obtained dispersion is finely pulverized by, for example, a jet mill. Further, by classifying the obtained fine powder with, for example, an air classifier, a colored toner having a predetermined particle diameter can be obtained.

  Subsequently, the obtained toner is mixed with an insulating liquid as a carrier liquid at a predetermined blending ratio. This mixture can be uniformly dispersed by a dispersing means such as a ball mill to obtain a liquid developer.

  The volume average particle diameter of the toner is suitably in the range of 0.1 μm or more and 5 μm or less. When the average particle diameter of the toner is less than 0.1 μm, the developability is greatly lowered. On the other hand, when the average particle diameter exceeds 5 μm, the quality of the image is degraded.

  An appropriate ratio of the toner particles to the liquid developer is about 10 to 50% by mass. When the amount is less than 10% by mass, the toner particles are liable to settle, and there is a problem in stability over time during long-term storage. Further, in order to obtain a required image density, it is necessary to supply a large amount of developer, the carrier liquid adhering to the paper increases, and it must be dried at the time of fixing, and steam is generated, resulting in environmental problems. If it exceeds 50% by mass, the viscosity of the liquid developer becomes too high, making it difficult to manufacture and handle.

  The viscosity of the liquid developer is preferably from 0.1 mPa · s to 10,000 mPa · s at 25 ° C. When it is 10,000 mPa · s or more, it becomes difficult to stir the carrier liquid and the toner, and the burden on the apparatus surface for obtaining a uniform liquid developer is large.

(Configuration and functional operation of the fixing device and the sheet conveying means)
A configuration example and operation of the fixing device and its periphery in the image forming apparatus of FIG. 1 will be described.

  As the fixing device 9, a non-contact heating unit 150 is provided. The non-contact heating unit 150 for fixing includes a heater 151 and a heat insulating cover 152.

  At a position facing the non-contact heating unit 150, a paper transport unit 160 is disposed.

  The sheet conveying means 160 is arranged so that the sheet 7 carrying an unfixed toner image is conveyed and receives heat radiation from the non-contact heating means 150 (heater 151).

  The toner on the conveyed paper 7 is melted and fixed by the non-contact heating means 150, and the carrier liquid is volatilized.

<Non-contact heating means>
A configuration example of the non-contact heating unit 150 will be described.

  In the non-contact heating means 150, a heater 151 is installed as a heat source in the heat insulating cover 152. The surface temperature of the heater 151 is controlled to be a desired temperature by a control unit (not shown). The sheet 7 is conveyed by the sheet conveying means 160 at a position where the heater 151 receives heat radiation.

  The heater 151 may be a long wavelength one such as a ceramic heater in consideration of the difference in light absorption between the black toner, the yellow, magenta, and cyan toners and the non-image portion of the paper 7. The surface temperature of the ceramic heater is about 500 to 700 ° C.

  The heat insulating cover 152 for keeping the temperature around the heater 151 at a high temperature may be made of a highly heat insulating and heat resistant material such as ceramic fiber. The heat insulating cover 152 preferably includes a heater 151 and is opened toward the paper transport unit 160 in order to efficiently supply heat to the paper 7.

<Paper conveying means>
A configuration example of the sheet transport unit 160 will be described.

  The paper transport unit 160 includes a transport belt 161 and belt driving rollers 163a and 163b that stretch and drive the transport belt 161. The belt driving rollers 163a and 163b function as driving means, and at least one of them is rotationally driven by power transmission from a driving source (not shown) and conveys the sheet 7 by rotating the stretched conveying belt 161. .

  A suction fan 162 is disposed on the opposite side of the conveyance belt 161 from the sheet 7 holding surface, and the sheet 7 is brought into close contact with the conveyance belt 161 by the suction fan 162. The sheet 7 is held such that the non-image surface side is in contact with the conveyance belt 161, and the image surface side is conveyed facing the non-contact heating unit 150.

  Instead of using the suction fan 162, the sheet 7 may be electrostatically brought into close contact with the transport belt 161.

<Cooling means and air moving means>
In FIG. 1, a belt cooling roller 164 is provided as a cooling means that abuts on the sheet conveying means 160 and cools the sheet conveying means (particularly the conveying belt 161). In addition, the first air moving means for supplying air for cooling to the cooling means, and the exhaust air that has absorbed heat from the cooling means are used as a region where the air around the non-contact heating means 50 is heated (inside the heat insulating cover 152). Air flow paths 165 and 166 (see FIG. 2) are provided as the second air moving means for supplying the air to the air).

  These detailed configurations and operations will be described later with reference to FIG.

  First, problems in the configuration of only the conventional non-contact heating unit 150 and the sheet conveying unit 160 will be described below.

<Fixing operation and conventional problems>
When the sheet 7 is conveyed by the sheet conveying unit 160 and reaches a position facing the non-contact heating unit 150, the sheet 7 on which the toner image and the carrier liquid are placed is mainly heated by the heat radiation from the heater 151 and remains. Most of the carrier liquid that had been stored volatilizes.

  In order to volatilize efficiently, not only the temperature of the paper 7 (the temperature of the carrier liquid) is maintained at a high temperature, but also the heat insulation that encloses the heater 151 in order to increase the saturated vapor pressure of the volatilized carrier liquid to facilitate volatilization. It is necessary to keep the internal atmosphere of the cover 152 at a high temperature.

  Moreover, while it is necessary to keep the inside of the non-contact heating means 150 (the inside of the heat insulating cover 152) at a high temperature, if the vapor of the volatilized carrier liquid stays inside the non-contact heating means 150, new volatilization is suppressed. It is necessary to ventilate by moving the vapor of the volatilized carrier liquid to the outside of the non-contact heating means 150.

  Therefore, as will be described later, in order to exhaust the air containing the steam in the non-contact heating means 150, a second air moving means for sending new air is provided.

  Focusing on the sheet conveying means 160, the sheet conveying means 160 is provided at a position facing the non-contact heating means 150, and is arranged so that the sheet 7 can be efficiently heated while being conveyed.

  However, the conveying belt 161 of the sheet conveying unit 160 is directly heated by the heat radiation from the non-contact heating unit 150 while the sheet 7 is not present.

  For example, when the non-contact heating unit 150 is warmed up or when the image forming apparatus is on standby (the non-contact heating unit 150 is maintained at a set temperature), or when a trouble such as a jam (paper jam) occurs (in this case, paper May exist).

  In these cases, it is possible to prevent overheating of the paper transport unit 160 by providing a shutter between the non-contact heating unit 150 and the paper transport unit 160 or by retracting the non-contact heating unit 150. .

  However, direct heating of the sheet conveying means 160 is unavoidable during the passage of the sheet 7 during continuous sheet passing. Of course, heat is also transferred from the sheet 7 to the conveying belt 161 during continuous sheet passing. Therefore, the temperature of the conveyor belt 161 continues to rise during continuous paper feeding.

  When the temperature of the conveyor belt 161 rises too much, a heat resistance problem occurs.

  For example, regarding the heat resistance of the conveyor belt 161, if it is a high heat-resistant rubber such as silicon rubber, up to about 200 ° C., if it is a high heat-resistant resin such as polyimide, 300 ° C. or higher, and if it is a metal belt, ensure 1000 ° C. or higher. Is possible.

  However, even if the heat resistance of the transport belt 161 can be ensured, a problem occurs during double-sided printing. The influence on the image already fixed on the first surface side at the time of duplex printing, that is, the surface that contacts the sheet conveying means 160 at the time of fixing the second surface cannot be avoided.

  It is desirable to maintain the temperature of the region of the conveyor belt 161 in contact with the first surface image (the region facing the non-contact heating means 150) at about 100 ° C. or less. This is because if the temperature of the conveying belt 161 is raised above the melting point of the toner, the toner is remelted and the image is disturbed, or in the worst case, an adverse effect such as offset to the conveying belt 161 occurs.

  Therefore, it is necessary to maintain the temperature of the conveyance belt 161 in the region in contact with the first surface side of the sheet 7 at about 100 ° C. or less.

(Cooling means and exhaust heat utilization)
In order to suppress the temperature rise of the sheet conveying means 160 (conveying belt 161), a cooling means (belt cooling roller 164) that contacts the sheet conveying means 160 and cools the sheet conveying means (particularly the conveying belt 161) is provided. . Also, a first air moving means (intake duct 165) for supplying cooling air to the cooling means, and a second for supplying the heat-absorbed exhaust from the cooling means to the non-contact heating means 150 (inside the heat insulating cover 152). Air moving means (connecting duct 166) is provided. Examples of these detailed configurations and operations will be described.

<First Embodiment>
FIG. 2A is a front view and FIG. 2B is a perspective view illustrating a schematic configuration related to fixing in the image forming apparatus according to the first embodiment. FIG. 2A is a view as seen from the upstream side in the paper conveyance direction. FIG. 2B omits the description of the duct, the heater, and the suction fan.

  A schematic configuration example relating to fixing in the image forming apparatus according to the first embodiment will be described with reference to FIGS.

  2A and 2B, the conveying belt 161 of the sheet conveying means 160 is stretched around a belt cooling roller 164 in addition to the belt driving roller 163.

  The belt cooling roller 164 is a cooling means for suppressing the temperature rise of the conveyor belt 161, and as described later, the temperature of the stretched conveyor belt 161 is supplied by continuously supplying new air into the roller. Prevent the rise.

  As the belt cooling roller 164, a metal roller such as aluminum having good thermal conductivity may be used.

  The belt cooling roller 164 is supplied with air at room temperature from the outside of the machine through an air supply duct 165 by an air flow formed by wind power generation means such as a fan (not shown). That is, the air supply duct 165 functions as first air moving means.

  The supplied air and the conveyor belt 161 are heat-exchanged by the belt cooling roller 164, the supplied air is heated, and the conveyor belt 161 is cooled.

  The heated air is guided to the air supply port 153 provided in the heat insulating cover 152 of the non-contact heating means 150 by the connecting duct 166. That is, the connecting duct 166 functions as a second air moving unit.

  The warm air supplied to the non-contact heating unit 150 is exhausted from the non-contact heating unit 150 through the exhaust duct 167 in a state including the vaporized vapor (carrier liquid) in the non-contact heating unit 150 by an air suction unit (not shown). Is done.

  With such a configuration, the hot air absorbed from the paper transport unit 160 can be supplied to the non-contact heating unit 150, while the paper transport unit 160 is cooled and the non-contact heating unit 150 is maintained at a high temperature. It becomes possible to perform ventilation in the state.

  The air containing the vaporized vapor (carrier liquid) exhausted from the non-contact heating means 150 may be supplied to a carrier liquid recovery device (not shown) through the exhaust duct 167. The carrier liquid recovered by the carrier liquid recovery device can be reused in the machine.

  In order to further improve the cooling performance of the sheet conveying means 160, a plurality of cooling means for cooling the conveying belt 161 may be provided, or air cooled to a room temperature or lower may be supplied.

  However, considering the input energy of the non-contact heating means 150, the conveyance 161 belt should be maintained at about 100 ° C. (If the conveyance belt 161 is cooled more than necessary, the toner, carrier liquid, and (paper) rise). Because it works against temperature.)

  For this purpose, the temperature of the conveyor belt 161 may be detected to adjust the air volume, and the temperature of the conveyor belt 161 may be controlled, or the air volume setting value may be determined in advance from the paper type, paper size, environment, number of sheets to be passed, etc. It may be stored in a memory.

  Moreover, the flow path of the air supply to the non-contact heating means 160 can be arranged in any direction. For example, in FIGS. 2 (a) and 2 (b), a flow path is provided so as to flow perpendicularly to the paper conveyance direction. However, as shown in the front view of FIG. Also good. Further, as shown in the perspective view of FIG. 3B, a flow path may be provided in parallel with the paper transport direction.

  As described above, the image forming apparatus having the non-contact heating unit is configured as the fixing unit for fixing the paper on which the toner image is formed. In other words, in the image forming apparatus according to the present embodiment, the first air movement is provided by the sheet conveying unit disposed opposite to the non-contact heating unit and the cooling unit that cools in contact with the sheet conveying unit. The cooling air is supplied to the cooling means by the means, and the heat absorbed by the cooling means is supplied to the heating area around the non-contact heating means by the second air moving means.

  According to the image forming apparatus according to the present embodiment, the hot air absorbed by the paper transport unit can be supplied to the non-contact heating unit, while the paper transport unit is cooled and the non-contact heating unit has a high temperature. Ventilation can be performed with the condition maintained.

  Thereby, it is possible to obtain a sufficient fixing quality with a simple structure, heat efficiency, energy saving.

<Second Embodiment>
FIG. 4A is a front view and FIG. 4B is a perspective view illustrating a schematic configuration related to fixing in the image forming apparatus according to the second embodiment. FIG. 4A is a view as seen from the upstream side in the paper conveyance direction. FIG. 4B omits the duct, the heater, and the suction fan.

  With reference to FIGS. 4A and 4B, a schematic configuration example relating to fixing in the image forming apparatus according to the second embodiment will be described only with respect to differences from the first embodiment.

  In the second embodiment, the belt driving roller 263b on the downstream side in the belt conveyance direction of the paper conveyance unit 160 also serves as a belt cooling roller. That is, the belt driving roller 263b is a driving unit and a cooling unit.

  Of course, the belt driving roller 263a on the upstream side in the belt conveyance direction may also serve as the belt cooling roller.

  In this way, by using both the driving unit and the cooling unit, a smaller and simpler apparatus configuration can be achieved while maintaining the fixing quality with high thermal efficiency.

<Third Embodiment>
FIG. 5A is a front view and FIG. 5B is a perspective view illustrating a schematic configuration related to fixing in the image forming apparatus according to the third embodiment. FIG. 5A is a view as seen from the upstream side in the paper conveyance direction. FIG. 5B omits the duct, the heater, and the suction fan.

  With reference to FIGS. 5A and 5B, a schematic configuration example relating to fixing in the image forming apparatus according to the second embodiment will be described only with respect to differences from the first and second embodiments.

  In the third embodiment, a plurality of belt cooling rollers 164a and 164b are arranged as cooling means so as to sandwich the conveying belt 161 of the sheet conveying means 160.

  Of course, the number and arrangement of the belt cooling rollers are not limited to this.

  As described above, even if the cooling unit is configured to increase the cooling effect of the sheet conveying unit 160, the absorbed heat can be supplied to the non-contact heating unit 150, and the internal atmosphere can be maintained at a high temperature. .

  As described above, the image forming apparatus according to the present embodiment is an image forming apparatus having a non-contact heating unit as a fixing unit for fixing a sheet on which a toner image is formed.

  In addition, the image forming apparatus according to the present embodiment includes a sheet conveying unit disposed to face the non-contact heating unit, and a cooling unit that cools in contact with the sheet conveying unit. In addition to the first air moving means for supplying air, the second air moving means for supplying the heat absorbed by the cooling means to the area where the air around the non-contact heating means is heated.

  As a result, the image forming apparatus according to the present embodiment can obtain a sufficient fixing quality with a simple configuration, heat efficiency, energy saving, and the like.

  In addition, the above-mentioned embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging apparatus 3 Exposure apparatus 4 Liquid developing apparatus 5 Intermediate transfer body 6 Cleaning apparatus 7 Recording medium (paper)
8 Liquid developer 9 Fixing device 150 Non-contact heating means 151 Heater (heat source)
152, 252 Thermal insulation cover 153, 253 Air inlet 160 Paper conveying means 161 Conveying belt 162 Suction fan 163, 163a, 163b, 263b Belt driving roller (driving means)
164, 164a, 164b Belt cooling roller (cooling means)
165, 365 Intake duct (first air moving means)
166, 266, 366 Connecting duct (second air moving means)
167 Exhaust duct

Claims (5)

As fixing means for fixing the toner image formed on the recording medium,
An image forming apparatus having non-contact heating means for heating the recording medium by heat radiation from a non-contact heat source,
A paper conveying means arranged opposite to the non-contact heating means and conveying the recording medium;
A cooling means that abuts on the paper conveying means and cools the paper conveying means;
First air moving means for supplying air for cooling the cooling means to the cooling means;
An image forming apparatus, comprising: a second air moving unit that supplies exhaust gas that has absorbed heat from the cooling unit to a region where air around the non-contact heating unit is heated. The non-contact heating means includes
The non-contact heat source;
A heat insulating cover that encloses the heat source and is opened toward the paper conveying means,
The image forming apparatus according to claim 1, wherein the second air moving unit supplies air into a heat insulating cover of the non-contact heating unit. The paper conveying means is
A conveyor belt;
The image forming apparatus according to claim 1, further comprising: a driving unit that drives the transport belt. The image forming apparatus according to claim 3, wherein the driving unit is the cooling unit and cools the driving belt while driving. The image forming apparatus according to claim 1, wherein the toner image on the recording medium is developed using a liquid developer.

Images