JP3987275B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a facsimile, a printer, and a plotter.
[0002]
[Prior art]
In a conventional electrophotographic image forming apparatus, an image forming unit for forming a toner image on a transfer material, a fixing unit for fixing the transfer material on which the toner image is formed by heat, a circuit for supplying power to each unit in the apparatus, and control. The image forming apparatus main body unit includes an electrical unit including a circuit to perform and a transfer material storage unit that stores a transfer material to be fed to the image forming unit. It is located above the material storage unit, so that it is easy to handle jamming, replace toner, and the like.
However, on the other hand, the paper feed tray in the transfer material storage unit that stores the transfer material such as paper is disposed below the image forming apparatus main body, so that the user replenishes the transfer material. There was a problem that heavy paper had to be set in a crouched state or a bent state, and it was difficult to handle.
In recent years, the speed of copying machines and printers has increased, and the frequency of replenishment of transfer materials has increased. However, jam processing has been reduced due to improved device reliability, so the main body of the image forming apparatus can accommodate transfer materials. There is less need to be above the part.
[0003]
By the way, in the conventional electrophotographic image forming apparatus, the transfer material arranged in the paper feed tray is fed out while maintaining the temperature and humidity depending on the storage environment conditions of the image forming apparatus, and is transferred to the transfer apparatus via a registration roller or the like. It reaches the middle part of the photoconductor. At this point, the toner image formed on the surface of the photosensitive member is transferred to the transfer material by the action of the transfer device. The transfer material onto which the toner image has been transferred enters a fixing device that further includes a fixing roller having a heat source therein and a pressure roller installed in pressure contact with the fixing roller, and the toner image is fixed on the transfer material. The The fixed transfer material is discharged to a paper discharge tray through a paper discharge roller, and a predetermined printing operation is completed.
[0004]
However, in the above-described prior art, the transfer material arranged in the paper feed tray enters the fixing device in a state where the temperature and humidity depending on the storage environment condition of the image forming apparatus is maintained. For this reason, when the transfer material is stored in a high humidity state, the transfer material is heated in a state containing a large amount of moisture, and as a result, water vapor generated from the transfer material is condensed inside the apparatus, which is transferred to the transfer material. There was a problem that the print quality was impaired by the contact. Further, since the transfer material is fixed in a state containing a large amount of moisture, there is a problem that the curl amount becomes very large.
[0005]
Therefore, as a method for solving the above problems, there is generally a system in which a heater for dehumidifying the transfer material is built in the paper feed tray. Further, as described in JP-A-6-202425, JP-A-7-140881, JP-A-7-199775, etc., the transfer material is heated to the transfer material storage unit by a fan to warm the transfer material. There are a drying method, a method including a preheating plate for heating the back surface of the transfer paper on the upstream side of the transfer path of the transfer unit, as described in JP-A-11-212402, JP-A-10-26893, and the like. . However, in these conventional techniques, since parts such as a blower fan and a heater are newly provided, there are problems that the number of parts is increased, the cost is increased, the apparatus is complicated, and the power consumption is increased.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and an object of the present invention is to propose an image forming apparatus having a configuration in which a transfer material storage portion is positioned above an image forming apparatus main body. Further, in order to solve the above-mentioned problems in the prior art, the present invention recovers heat from printed paper discharge and applies it to the upper surface of the transfer material such as paper in the transfer material storage portion, The object is to propose an image forming apparatus that can dehumidify. Furthermore, when the transfer material is dehumidified, water vapor is prevented from accumulating in the paper cassette, and the transfer material absorbs moisture again. The purpose of this is to reduce the curl of the paper discharge by giving the water vapor to the printed paper discharge.
[0007]
[Means for Solving the Problems]
As means for achieving the above object, the invention according to claim 1 is directed to an image forming unit for forming a toner image on a transfer material, a fixing unit for fixing the transfer material on which the toner image is formed by heat, and each unit in the apparatus. An image forming apparatus of an electrophotographic system having an image forming apparatus main body part including an electric part including a circuit for supplying power to and a control circuit, and a transfer material storage part for storing a transfer material fed to the image forming part in the previous SL said transfer material housing portion disposed in the upper than the image forming apparatus main body, a paper discharge tray provided close to the upper surface of the transfer material accommodating portion, and a sheet discharge tray top surface, the transfer material housing A heat conducting member is arranged between the upper surface of the transfer material loaded on the part .
[0008]
In the invention according to ie claim 1, by arranging the heat conductive member between the upper surface of the stacked transfer material to the transfer material housing portion and the sheet discharge tray upper surface, the heat from the print has been discharged paper collecting In addition, the transfer material can be dehumidified by applying it to the upper surface of the transfer material such as paper in the transfer material storage unit.
The invention according to claim 2, in the image forming apparatus according to claim 1, in which characterized in that a vent hole in the heat conductive member and the sheet discharge tray. That is, in the invention according to claim 2 , the transfer material storage portion is released by releasing the moisture when the transfer material is dehumidified by heating with the heat from the heat conducting member in claim 1 from the vent hole provided in the discharge tray. This prevents water from accumulating in the paper cassette and prevents the transfer material from absorbing moisture again, and also applies the water vapor to the printed paper to reduce paper curl. is there.
[0009]
Since the dehumidifying mechanism according to the first aspect of the present invention uses the exhaust heat of the printed paper, the effect is exhibited after the start of the printing operation, and therefore does not function in the standby state of the image forming apparatus main body.
Therefore, as a means for solving such a problem, the invention according to claim 3 is the image forming apparatus according to claim 1 or 2 , wherein a ventilation duct that communicates from the fixing unit or the electrical unit to the transfer material storage unit is provided. It is characterized by that. That is, in the invention according to claim 3 , a ventilation duct leading from the fixing unit or the electrical unit to the transfer material storage unit is provided, and the heat released from the fixing unit or the electrical unit is naturally increased to the transfer material storage unit. It directs hot air to dehumidify the transfer material.
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect , the ventilation duct leading from the fixing unit or the electrical component unit to the transfer material storage unit is formed of a heat insulating member. Is. That is, in the invention according to claim 4 , in order to prevent the temperature of the high-temperature air flow in the ventilation duct in claim 3 from decreasing, the inside of the ventilation duct is formed of a heat insulating member to prevent the dehumidification effect from being reduced. .
[0010]
In the image forming apparatus according to claim 3 or 4, since the water vapor generated from the fixing unit during the printing operation reaches the transfer material storage unit, the dehumidified transfer material may be humidified again. Accordingly, the invention according to claim 5 is the image forming apparatus according to claim 3 or 4 , and a member that closes the ventilation duct that leads from the fixing unit to the transfer material storage unit when passing paper, and an opening / closing mechanism and control for the member. Means is provided. That is, the invention according to claim 5 solves the above-mentioned problems by providing a member for closing the ventilation duct, an opening / closing mechanism for the member and a control means, and closing the ventilation duct at the start of printing. is there.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration, operation and action of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a schematic configuration diagram showing an example of a normal electrophotographic image forming apparatus (for example, a printer). In this image forming apparatus, an image forming unit 1a for forming a toner image on a transfer material, a fixing unit 1b for fixing the transfer material on which the toner image is formed by heat, and a circuit for supplying power to each unit in the apparatus and control are performed. There is an image forming apparatus main body 1 composed of an electrical component 1c including a circuit and the like, and a transfer material storage 1d for storing a paper feed cassette 1e storing a transfer material 3c is disposed below the image forming apparatus main body 1. Has been. Further, in the image forming unit 1a, a photoreceptor 2a that is an image carrier, and a charging device 2b, an optical writing device 2c, a developing device 2d, a transfer device 2e, and a cleaning device 2f arranged around the photoreceptor 2a. Etc. are provided.
[0012]
In the image forming apparatus (printer) having the configuration shown in FIG. 2, when the printing operation is started, first, the surface of the photoreceptor 2a is charged by the charging device 2b, and then the laser beam corresponding to the image information by the optical writing device 2c. Etc., and an electrostatic latent image is formed. The electrostatic latent image on the photoreceptor 2a is developed with the toner of the developing device 2d to be visualized. The transfer material 3c stored in the paper feed cassette 1e of the transfer material storage portion 1d is sent out in time with the toner image forming operation, and reaches the intermediate portion between the transfer device 2e and the photoreceptor 2a via a registration roller. . At this time, the toner image formed on the surface of the photoreceptor 2a is transferred to the transfer material by the action of the transfer device 2e, and a toner image is formed on the transfer material. The transfer material 3c onto which the toner image has been transferred enters the fixing device 1b including a fixing roller having a heat source therein and a pressure roller installed so as to be in pressure contact with the fixing roller, and the toner image is transferred to the transfer material 3c. To be established. The fixed transfer material 3c is discharged to the paper discharge tray 1f through the paper discharge roller of the paper discharge port 3b, and the predetermined printing operation is completed.
[0013]
By the way, in the image forming apparatus having the configuration and operation as shown in FIG. 2, the image forming apparatus main body 1 is positioned above the transfer material storage 1d, so that it is easy to perform jam processing, toner replacement, and the like. ing. However, on the other hand, since the paper feed cassette 1e in the transfer material storage portion 1d for storing the transfer material 3c such as paper is disposed below the image forming apparatus main body portion 1, the user can use the transfer material 3c. When replenishing, heavy paper must be set in a crouched state or a bent state, which is difficult to handle.
[0014]
In this invention, as shown in FIG. 1, Ru der those configured to arrange the transfer material accommodating portion 1d to the upper than the image forming apparatus main body 1. That is, since the transfer material storage portion 1d is arranged above the image forming apparatus main body portion 1, the sheet feeding cassette 1e in the transfer material storage portion 1d is at a high position, so that the user can bend his body. It is not necessary to supply the transfer material 3c in a crouched state, and the apparatus becomes easy to handle.
FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is the same as FIG. 2 except that the transfer material storage unit 1d is arranged above the image forming apparatus main body 1. 1 having the same reference numerals as those in FIG. 2 are the same components, and the operations are also the same. However, since the transfer material storage portion 1d is arranged above the image forming apparatus main body portion 1, the paper discharge tray 1f is provided close to the upper surface of the transfer material storage portion 1d.
[0015]
Next, FIG. 3 is a schematic configuration diagram of an image forming apparatus showing another embodiment of the present invention. In this embodiment, in the image forming apparatus of FIG. 1, the sheet is discharged close to the upper surface of the transfer material storage portion 1d. A tray 1f is provided, and the heat conducting member 3a is arranged between the upper surface of the paper discharge tray and the upper surface of the transfer material 3c loaded on the paper feed cassette 1e in the transfer material storage portion 1d. (Claim 1 ). In the image forming apparatus shown in FIG. 3, the heat conductive member 3a is a member made of a material having good heat conductivity such as aluminum or copper, and the upper surface of the transfer material 3c loaded on the discharge tray upper surface and the transfer material storage portion 1d. By disposing the heat conducting member 3a between the heat transfer member 3a and the heat transfer member 3a, heat is recovered from the printed paper discharge and applied to the upper surface of the transfer material 3c such as paper in the transfer material storage portion 1d. Is possible.
[0016]
More specifically, in the image forming apparatus having the configuration shown in FIG. 3, the transfer material 3c on which the toner image is formed by the image forming unit 1a by the printing operation is fixed by the fixing unit 1b and then discharged from the paper discharge port 3b. However, the transfer material 3c after fixing is hot, and this tendency is particularly strong in recent high-speed machines. Therefore, the heat of the paper discharged stacked on the paper discharge tray 1f is transmitted to the transfer material 3c in the paper feed cassette 1e of the transfer material storage portion 1d through the heat conducting member 3a, and the transfer material 3c is warmed, thereby transferring the transfer material 3c. Is dehumidified. At the same time, the fixed transfer material (paper discharge) after printing is deprived of heat on the paper discharge tray 1f and cooled, reducing the risk of burns and discomfort when the user touches the paper discharge. can do.
[0017]
Next, FIG. 4 is a schematic configuration diagram of an image forming apparatus showing still another embodiment of the present invention. In this embodiment, in the image forming apparatus of FIG. 3, vent holes are formed in the paper discharge tray 1f and the heat conducting member 3a. The opening 4a is formed as follows (claim 2 ). In other words, in the image forming apparatus having the configuration shown in FIG. 4, the moisture (heat vents) provided in the heat conductive member 3a and the paper discharge tray 1f is removed when the transfer material 3c is dehumidified by heat from the heat conductive member 3a. ) By escaping from 4a, water vapor is prevented from accumulating in the paper feed cassette 1e of the transfer material storage unit 1d, the transfer material 3c is prevented from absorbing moisture again, and the water vapor is printed on the printed sheet. Giving and reducing the curl of the paper discharge.
[0018]
More specifically, generally, when the printing side of a transfer material 3c such as paper is heated during fixing, a so-called face curl occurs in which the transfer material becomes concave with the printing surface facing upward, but the paper discharge tray 1f and the heat conducting member 3a If an opening (ventilation hole) 4a is provided in the transfer material 3c in the sheet feeding cassette 1e of the transfer material container 1d, air containing the moisture passes through the opening (ventilation hole) 4a and is exhausted. The paper discharged on the paper tray 1f is touched, and the printed surface of the discharged paper absorbs moisture again, so that curling can be reduced.
[0019]
By the way, since the dehumidifying mechanism dehumidifies the transfer material 3c by using the exhaust heat of the printed paper, the effect is exhibited after the start of the printing operation. Therefore, the dehumidifying mechanism does not function in the standby state of the image forming apparatus main body. Therefore, as a means for solving such a problem, in the image forming apparatus shown in FIG. 4, in addition to the dehumidification method using the exhaust heat of the paper discharge, the transfer material storage unit 1d from the fixing unit 1b or the electrical unit 1c. The ventilation ducts 4b and 4c leading to are provided (claim 3 ). That is, in the image forming apparatus having the configuration shown in FIG. 4, the ventilation ducts 4b and 4c leading from the fixing unit 1b or the electrical unit 1c to the transfer material storage unit 1d are provided, and the heat released from the fixing unit 1b or the electrical unit 1c is naturally generated. Taking advantage of the rising characteristics, the transfer material 3c is dehumidified by introducing hot air to the transfer material storage portion 1d.
Thus, by providing the ventilation ducts 4b and 4c so that high-temperature air flows by natural convection from the fixing unit 1b to the transfer material storage unit 1d and from the electrical component 1c to the transfer material storage unit 1d, the transfer material storage unit 1d The atmospheric temperature rises and the transfer material 3c is dehumidified, and excessive curling during fixing can be prevented.
[0020]
Next, FIG. 5 is a schematic configuration diagram of an image forming apparatus showing still another embodiment of the present invention. In this embodiment, similarly to the image forming apparatus of FIG. 4, the transfer material is transferred from the fixing unit 1b or the electrical unit 1c. Ventilation ducts 4b and 4c leading to the storage portion 1d are provided, and the ventilation ducts 4b and 4c are formed of a heat insulating member 5a (claim 4 ).
By forming the ventilation ducts 4b and 4c with the heat insulating member 5a in this way, it is possible to prevent a decrease in the air temperature for dehumidifying the transfer material 3c, so that the efficiency of the dehumidifying effect can be enhanced and the image It is possible to prevent the formation portion 1a from being adversely affected by heat from the ventilation ducts 4b and 4c.
[0021]
Next, FIG. 6 is a schematic configuration diagram of an image forming apparatus showing still another embodiment of the present invention. In this embodiment, in addition to the configuration of the image forming apparatus of FIG. 4 or FIG. And a member 6a for closing the ventilation duct 4b leading to the transfer material storage portion 1d, and an opening / closing mechanism and a control means for the member 6a are provided (claim 5 ).
More specifically, as shown in FIG. 6, a ventilation duct 6b that branches from the middle of the ventilation duct 4b that leads from the fixing unit 1b to the transfer material storage unit 1d and opens to the side wall of the image forming apparatus main body 1 is newly provided. The ventilation duct 4b on the side leading from the fixing section 1b to the transfer material storage section 1d is used as the air flow path R1 in standby mode, and the ventilation duct 6b on the side branched from the middle and opened to the side wall of the image forming apparatus main body 1 is printed. The air flow path R2 at the time. A flow path switching valve 6a that switches between the two flow paths R1 and R2 is provided as an opening / closing member in the branch portion, and the flow path switching valve is used to open and close the ventilation duct 4b that leads from the fixing portion 1b to the transfer material storage portion 1d. Control by 6a. That is, during standby, the flow path R1 of the ventilation duct 4b leading from the fixing unit 1b to the transfer material storage unit 1d is opened, and the heat of the fixing unit 1b is guided to the transfer material storage unit 1d to dehumidify the transfer material 3c. During the printing operation, the opening / closing mechanism of the flow path switching valve 6a is controlled to close the flow path R1 of the ventilation duct 4b leading from the fixing section 1b to the transfer material storage section 1d by the switching valve 6a. The flow path R2 of the ventilation duct 6b on the opening side is opened to release water vapor during fixing from the ventilation duct 6b to the outside. Accordingly, since the water vapor generated from the fixing unit 1b during the printing operation does not reach the transfer material storage unit 1d, the dehumidified transfer material is prevented from being humidified again.
[0022]
【The invention's effect】
As described above, in the present invention , an image forming unit that forms a toner image on a transfer material, a fixing unit that fixes the transfer material on which the toner image is formed by heat, a circuit that supplies power to each unit in the apparatus, and control are performed. In an electrophotographic image forming apparatus having an image forming apparatus main body portion including an electrical part including a circuit and the like, and a transfer material storage portion for storing a transfer material fed to the image forming portion, the transfer material storage portion Since the sheet feeding cassette in the transfer material storage unit is positioned higher than the image forming apparatus main body, the user replenishes the transfer material with his body bent or crouched. This eliminates the need to handle the device.
[0023]
According to the first aspect of the present invention, in the image forming apparatus having the above-described configuration, a paper discharge tray is provided in the vicinity of the upper surface of the transfer material storage unit, and is stacked on the upper surface of the paper discharge tray and the transfer material storage unit. Since the heat conduction member is arranged between the upper surface of the transfer material, heat can be recovered from the printed paper and applied to the upper surface of the transfer material in the transfer material storage section. In addition, the transfer material can be dehumidified. In addition, since the fixed transfer material (printed paper) after printing is deprived of heat on the paper discharge tray and cooled, it reduces the risk of burns and discomfort when the user touches the paper output. be able to.
The invention according to claim 2, in the image forming apparatus according to claim 1, wherein, with the construction in which a vent hole in the heat conductive member and the sheet discharge tray, heating the transfer material by heat from the heat conducting member By removing the moisture from the dehumidification through the vent hole provided in the paper discharge tray, it is possible to prevent water vapor from accumulating in the paper feed cassette of the transfer material storage unit, and the transfer material absorbs moisture again. The effect which prevents it can be acquired. Further, the water vapor can be applied to the printed paper discharge to reduce the curl of the paper discharge.
[0024]
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect , a fixing duct or an electrical component is provided by providing a ventilation duct that leads from the fixing unit or the electrical component to the transfer material storage unit. The transfer material can be dehumidified by introducing hot air to the transfer material storage part by utilizing the characteristic that the heat released from the water naturally rises.
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect , the ventilation duct leading from the fixing unit or the electrical unit to the transfer material storage unit is formed of a heat insulating member. Since it is possible to prevent a decrease in the air temperature for dehumidifying the transfer material, it is possible to increase the efficiency of the dehumidifying effect and to prevent the image forming unit from being adversely affected by the heat from the ventilation duct. it can.
[0025]
According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect , a member that closes a ventilation duct that communicates from the fixing unit to the transfer material storage unit when paper is passed, and an opening / closing mechanism and a control unit for the member. Due to the configuration, the ventilation duct leading from the fixing unit to the transfer material storage unit can be closed during the printing operation, and water vapor generated from the fixing unit does not reach the transfer material storage unit. It is prevented that the material is humidified again.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram illustrating an example of a normal electrophotographic image forming apparatus.
FIG. 3 is a schematic configuration diagram of an image forming apparatus showing another embodiment of the present invention.
FIG. 4 is a schematic configuration diagram of an image forming apparatus showing still another embodiment of the present invention.
FIG. 5 is a schematic configuration diagram of an image forming apparatus showing still another embodiment of the present invention.
FIG. 6 is a schematic configuration diagram of an image forming apparatus showing still another embodiment of the present invention.
[Explanation of symbols]
1: Image forming apparatus main body 1a: Image forming unit 1b: Fixing unit 1c: Electrical unit 1d: Transfer material storage unit 1e: Paper feed cassette 1f: Paper discharge tray 2a: Photoconductor (image carrier)
2b: charging device 2c: optical writing device 2d: developing device 2e: transfer device 2f: cleaning device 3a: heat conducting member 3b: discharge port 3c: transfer material 4a: vent hole (opening)
4b, 4c: Ventilation duct 5a: Heat insulating material 6a: Flow path switching valve (opening / closing member)

Claims (5)

Image formation comprising an image forming unit for forming a toner image on a transfer material, a fixing unit for fixing the transfer material on which the toner image is formed by heat, a circuit for supplying power to each unit in the apparatus, and a circuit for performing control. The device body,
In an electrophotographic image forming apparatus having a transfer material storage portion for storing a transfer material to be fed to the image forming portion,
The transfer material housing portion in the upper than before Symbol image forming apparatus main body is arranged, close to the upper surface of the transfer material accommodating portion is provided the output tray, and the paper discharge tray upper surface, to the transfer material housing portion An image forming apparatus , wherein a heat conductive member is disposed between the upper surface of the loaded transfer material . The image forming apparatus according to claim 1.
An image forming apparatus comprising a vent hole in the discharge tray and the heat conducting member . The image forming apparatus according to claim 1 or 2 ,
An image forming apparatus, comprising: a ventilation duct that leads from the fixing unit or the electrical unit to the transfer material storage unit . The image forming apparatus according to claim 3 .
An image forming apparatus, wherein a ventilation duct leading from the fixing unit or the electrical unit to the transfer material storage unit is formed of a heat insulating member . The image forming apparatus according to claim 3 or 4 , wherein:
An image forming apparatus comprising: a member that closes a ventilation duct that communicates from the fixing unit to the transfer material storage unit when a sheet is passed; an opening / closing mechanism for the member; and a control unit .

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