JP2005257893A - Sheet cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet cooling device in which sheets are sufficiently cooled even when the sheets are consecutively fed, and stable cooling effect is exhibited. <P>SOLUTION: The sheet cooling device includes a conveyance passage along which a sheet is guided downstream of a heat fixing device. The conveyance passage is formed from a member that has opposite faces. The member is composed of a heat insulation material or covered with the heat insulation material. The sheet cooling device has openings perpendicular to the direction of the sheet conveyance so as to continue from the conveyance passage formed from the opposite faces. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sheet cooling apparatus that cools a sheet after heat-fixing a toner image transferred to the sheet in an image forming apparatus such as a copying machine, a laser beam printer, and a facsimile machine.

  First, an electrophotographic copying machine as an example of an electrophotographic image forming apparatus according to the present invention will be described with reference to FIG.

In FIG. 7, reference numeral 100 denotes an electrophotographic copying machine main body (hereinafter referred to as an apparatus main body). The document is placed on the platen glass 102. A light image corresponding to the image information is formed on the CCD 122 by the plurality of mirrors M and the lens Ln of the optical unit 103, and the CCD 122 reads the image information. The read image information is imaged on the drum 104 by the laser scanner 123. Reference numeral 105 denotes a cassette. Recording materials loaded on these cassettes 105 (hereinafter “
A suitable sheet is selected from the sheet size information of the cassette 105 from the information input by the user from the operation unit or the sheet size of the document. Here, the sheet is not limited to paper, and can be selected as appropriate, such as an OHP sheet.

  Then, the single sheet P conveyed by the paper feeding / separating device 105 a is conveyed to the registration roller 108 via the conveyance unit 106 and the pre-registration conveyance guide unit 107. Reference numerals 109 and 110 denote a transfer charger and a separation charger. Here, the toner image formed on the drum 104 is transferred onto the sheet P by the transfer charger 109. Then, the separation charger 110 separates the sheet P on which the toner image is transferred from the drum 104.

  Thereafter, the sheet P conveyed by the conveying unit 111 is fixed on the toner image on the sheet by heat and pressure in the fixing device 112. In the case of single-sided copying, after passing through the inner discharge roller 113, the sheet P is The paper is discharged outside the main body by a paper discharge roller 114. In the case of double-sided copying, the paper is temporarily transported to the reverse path 117 via the refeed transport path 116 under the control of the flapper 115. Here, the end of the sheet P passes through the refeed conveyance path 116, and is conveyed again into the apparatus by rotating the reverse roller 118 in reverse at the timing still held by the reverse roller 118. Thereafter, the sheet P passes through the pre-registration conveyance guide unit 107 again through the duplex path 119 and is conveyed to the registration roller 108, and then is discharged to the outside of the main body apparatus through the same path as in the case of single-sided copying. .

  The sheet P thus heat-fixed by the fixing device 112 has heat. In particular, in the case of double-sided copying, after heat-fixing, the paper passes through the refeed conveyance path 116, the reverse path 117, and the double-sided path 119 and is conveyed again to the drum. At this time, since the re-feeded sheet P has heat, when the toner image is transferred to the sheet P again, the drum 104 and its peripheral portion are heated and the temperature rises. When the temperature of the drum 104 and its peripheral portion, particularly the cleaning device 120 rises, a phenomenon called blocking occurs in which the toner in this portion melts slightly and then hardens again. When blocking occurs, the toner adheres to the drum 104, the cleaning device 120, etc., and an appropriate toner image cannot be transferred onto the sheet P.

  Therefore, in order to solve such a problem, as described in Patent Document 1, a fan 121 is arranged in the conveyance path after the toner image is fixed on the sheet by the fixing device, and is sent by the fan 121. A sheet cooling apparatus has been proposed in which a sheet is cooled by the air that is generated.

JP-A-5-2349

  However, the conventional example has the following problems.

  That is, in the image forming apparatus provided with the sheet cooling apparatus configured as in the conventional example, when the sheets are continuously copied on both sides, the temperature in the apparatus body gradually rises due to the fixing device or the like. Even if the sheet is cooled by the fan in this state, the sheet is not sufficiently cooled, and heats the drum and its peripheral part. Further, since the air cooled by the fan is heated by the sheet, the temperature rises. Since the air is sent directly into the apparatus main body, the temperature in the apparatus main body is further increased.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the object of the present invention is to provide a sheet cooling apparatus that exhibits a stable cooling effect because the sheets are always sufficiently cooled even when sheets are continuously fed. There is to do.

  In order to achieve the above object, a sheet cooling apparatus according to the present invention includes a conveyance path that guides a sheet downstream of a heat fixing apparatus, and includes a member having a surface that the conveyance path is opposed to. It is comprised or it is covered with the heat insulating material.

  The sheet cooling apparatus according to the present invention is characterized in that an opening is provided in a direction perpendicular to the sheet conveying direction from a conveying path constituted by opposing surfaces.

  The sheet cooling apparatus according to the present invention is characterized in that the opening is connected to the conveyance path.

  The sheet cooling apparatus according to the present invention is characterized in that the opening communicates with the outside air.

  The sheet cooling device according to the present invention is characterized in that, at the entrance or exit of the sheet of the conveyance path constituted by the opposed surfaces, the distance between the opposed surfaces is narrower than other portions.

  The sheet cooling apparatus according to the present invention is configured such that air is drawn between the opposed surfaces of the apparatus body from the outside air between the opposed surfaces, or air is discharged from the opposed surfaces to the outside of the apparatus main body. It is characterized by having installed.

  The sheet cooling apparatus according to the present invention is characterized in that two or more air blowing means are installed, and the air volume of the air blowing means sucked from the outside air is larger than the air volume of the air blowing means discharged to the outside of the apparatus.

  In the sheet cooling apparatus according to the present invention, since the member constituting the conveyance path is a heat insulating material, the temperature in the conveyance path remains in the apparatus main body even if the temperature in the apparatus main body rises by continuously performing double-sided copying or the like. It becomes difficult to be affected by the temperature of Accordingly, it is possible to provide a sheet cooling unit that exhibits a stable cooling effect even when continuous duplex copying or the like is performed.

  Since the sheet cooling apparatus according to the present invention has an opening in the direction perpendicular to the sheet conveying direction from the conveying surface, even if the temperature in the apparatus main body rises due to continuous double-sided copying, etc. The temperature in the path is hardly affected by the temperature in the apparatus main body, and is always almost the same as the temperature of the outside air. Since the sheet is always cooled at the same temperature as the outside air, the sheet is always sufficiently cooled. Therefore, it is possible to provide a sheet cooling unit that always exhibits a stable cooling effect without changing the cooling effect even when double-sided copying is continuously performed.

  In the sheet cooling apparatus according to the present invention, since the opening is connected to the conveyance surface, the temperature in the conveyance path is less affected by the temperature in the apparatus main body. Accordingly, it is possible to provide a sheet cooling unit that exhibits a more stable cooling effect without changing the cooling effect even when double-sided copying is continuously performed.

  In the sheet cooling apparatus according to the present invention, since the opening communicates with the outside air, fresh outside air enters the conveyance path, and the sheet cooling efficiency is improved.

  In the sheet cooling apparatus according to the present invention, since the distance between the opposing surfaces is narrower than the other portions at the entrance or exit of the sheet of the conveyance path constituted by the opposing surfaces, continuous duplex copying, etc. Even if the temperature in the apparatus main body rises, the temperature in the conveyance path is less affected by the temperature in the apparatus main body, so that a more stable sheet cooling apparatus can be provided.

  The sheet cooling apparatus according to the present invention is configured such that air is drawn between the opposed surfaces of the apparatus body from the outside air between the opposed surfaces, or air is discharged from the opposed surfaces to the outside of the apparatus main body. Therefore, fresh outside air always enters the conveyance path, and the sheet cooling efficiency is further improved.

  In the sheet cooling apparatus according to the present invention, since two or more air blowing means are installed and the air volume of the air blowing means sucked from the outside air is larger than the air volume of the air blowing means discharged to the outside of the apparatus, the inside of the conveying path becomes positive pressure, and the inside of the conveying path The air is blown out toward the inside of the apparatus main body also at the inlet and outlet of the sheet in the conveyance path. The air in the conveyance path is completely unaffected by the temperature in the apparatus main body, and a more stable sheet cooling apparatus can be provided.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
(Description of configuration)
An embodiment of an image forming apparatus 1 including the present invention will be described with reference to the drawings. FIG. 2 is an explanatory cross-sectional view schematically showing a schematic configuration of an electrophotographic copying machine as an image forming apparatus.

  In FIG. 2, 2 is an image carrier (for example, a drum-shaped electrophotographic photosensitive member or a belt-shaped electrophotographic photosensitive member, hereinafter referred to as a drum), and 3 is a latent image formed on the drum 2. A developing device that develops a visible image by attaching a developer, that is, a developing device that develops a latent image, 4 is a hopper that feeds the developer (the developer in the present embodiment is a one-component magnetic toner) to the developing device 3, 5 is a transfer means for transferring the developed image visualized on the drum 2 to a sheet (recording medium), 6 is a cleaning device for removing the developer and other deposits remaining on the drum 2, and 7 is the drum 2. 8 is a primary charger that uniformly charges the surface of the drum 2, 9 is an optical reading system that reads image information of the document, and 9a is an image reader that exposes the image information on the drum 2. Exposure unit for forming a latent image, 1 Is a document processing apparatus that guides the document to the image reading unit, 11 is a sheet feeding unit that feeds the sheet P to the image forming unit, 12 is a transport table that transports the sheet P, and 13 is a sheet P transferred by the image forming unit. A fixing device for fixing the upper image (developer image) to the sheet P, 14 a sheet discharge unit for discharging the sheet P on which image formation has been completed, and 15 a sheet refeed for guiding the sheet P to be re-fed during double-sided recording A conveyance path, 16 is a reversing path for reversing the sheet P to be re-fed, and 17 is a double-sided path for conveying the reversed sheet P to the developing device 3.

  Here, the sheet cooling apparatus according to the present invention will be described with reference to FIG.

  The refeed conveyance path includes a refeed conveyance guide A15a and a refeed conveyance guide B15b. The refeed conveyance guide A15a and the refeed conveyance guide B15b are made of a heat insulating material. The entrance side and the exit side of the re-feed conveyance guide B15b are particularly configured such that the distance between the re-feed conveyance guide B15b and the re-feed conveyance guide A15a is shortened. A direction perpendicular to the sheet conveyance direction of the refeed conveyance guide A154a and the refeed conveyance guide B15b is connected to the exterior 1a of the apparatus main body. A louver 18 is provided in the exterior 1a portion of the apparatus main body sandwiched between the refeed conveyance guide A15a and the refeed conveyance guide B15b (see FIG. 3).

  The reversing path 16 includes a reversing path guide A16a and a reversing path guide B16b, and has the same configuration as the refeed conveyance path.

The double-sided path includes a double-sided path guide A 17a and a double-sided path guide B 17b, and has the same configuration as the refeed conveyance path.
(Description of operation)
Next, the operation of the image forming apparatus will be described.

The document is placed on the document table glass 9b. Then, a light image corresponding to the image information is formed on the CCD 25 by the plurality of mirrors M and the lens Ln of the exposure unit 9a, and the CCD 25 reads the image information. The read image information is imaged on the drum 2 by the laser by the laser scanner 26. Recording materials loaded on the sheet feeding unit 11 (hereinafter referred to as “
From the sheet size information of the sheet feeding unit 11, an appropriate sheet P is selected from the information input by the user from the operation unit or the sheet size of the document. Here, the sheet P is not limited to paper, and may be selected as appropriate, for example, an OHP sheet.

  Then, the single sheet P conveyed by the paper feeding / separating device 11a is conveyed to the registration roller 19 via the conveyance unit 12a and the pre-registration conveyance guide unit 12b, and the rotation of the drum 2 and the exposure unit 9a Conveys with synchronized scanning timing. Reference numerals 5a and 5b denote a transfer charger and a separation charger. Here, the toner image formed on the drum 2 is transferred to the sheet P by the transfer charger 5a. Then, the sheet P on which the toner image is transferred is separated from the drum 2 by the separation charger 5b.

  Thereafter, after the sheet P conveyed by the conveying unit 12a fixes the toner image on the sheet P by heat and pressure in the fixing device 14, and in the case of single-sided copying, after passing through the inner paper discharge roller 20, The sheet is discharged to the sheet discharge unit 14 by the outer discharge roller 21. In the case of double-sided copying, the paper is temporarily transported to the reversing path 16 via the refeed transport path 15 under the control of the flapper 22. Here, the end of the sheet P passes through the re-feed conveyance path 15 and is conveyed again into the apparatus by rotating the reversing roller 16c in reverse at the timing still held between the reversing rollers 16c. Thereafter, after passing through the pre-registration conveyance guide portion 12b via the double-sided path 17 and being conveyed to the registration roller 19, it is discharged to the sheet discharge portion 14 through the same path as in the case of single-sided copying.

  Next, the operation of the sheet cooling device will be described.

  In the case of duplex copying, the sheet P is conveyed to the refeed conveyance path 15. The re-feed conveyance path 15 includes a re-feed conveyance guide A15a and a re-feed conveyance guide B15b made of heat insulating material. The air in the refeed conveyance path 15 is connected to the outside air by a louver 18 installed in the exterior 1a of the apparatus main body. Therefore, the inside of the refeed conveyance path 15 is always at the same temperature as the outside air.

  When the sheet P is continuously copied on both sides, the temperature in the apparatus body gradually increases. However, since the refeed conveyance guide A15a and the refeed conveyance guide B15b are made of a heat insulating material, the air in the refeed conveyance path 15 is not affected by the temperature in the apparatus main body. Further, the distance between the refeed conveyance guide A15a and the refeed conveyance guide B15b is particularly short on the sheet entrance side and the exit side of the refeed conveyance path 15, so that there is almost no influence of the temperature in the apparatus main body. I have to. Accordingly, the temperature in the refeed conveyance path 15 is always kept at the same temperature as the outside air. Even if the sheet P is continuously fed through the refeed conveyance path 15, the temperature in the refeed conveyance path 15 hardly changes with respect to the outside air, so that the same sheet cooling effect can always be obtained. .

  By the same operation in the reversing path 16 and the double-sided path 17, the temperature in the reversing path 16 and the double-sided path 17 hardly changes with respect to the outside air.

  According to the above configuration, the temperatures in the refeed conveyance path 15, the reversing path 16, and the double-sided path 17 are always the same as the outside air without increasing even if double-sided copying is performed continuously. Cooled with a stable cooling effect.

  In the present embodiment, the refeed conveyance path 15, the reversing path 16, and the double-sided path 17 are heat insulating materials, but the heat insulating material may be a mold material such as ABS.

  In this embodiment, the refeed conveyance path 15, the reversing path 16, and the double-sided path 17 are used as heat insulating materials. However, the refeeding conveyance path 15, the reversing path 16, and the double-sided path 17 are generally used, for example. It may be covered with a heat insulating sheet or the like.

  In the present embodiment, the refeed conveyance path 15, the reversing path 16, and the duplex path 17 are arranged so as to contact the exterior 1a. However, as shown in FIG. Even if the double-sided path 17 is disposed in the vicinity of the exterior 1a, substantially the same effect can be obtained, so that the refeed conveyance path 15, the reverse path 16, and the double-sided path 17 are disposed in the vicinity of the exterior 1a. Also good.

<Embodiment 2>
(Description of configuration)
The configuration of the second embodiment will be described with reference to FIG.

  The refeed conveyance path 15 includes a refeed conveyance guide A15a and a refeed conveyance guide B15b. The refeed conveyance guide A15a and the refeed conveyance guide B15b are made of a heat insulating material. The entrance side and the exit side of the re-feed conveyance guide B15b are particularly configured so that the distance between the re-feed conveyance guide B15b and the re-feed conveyance guide A15a is shortened. A direction perpendicular to the sheet conveying direction of the refeed conveyance guide A15a and the refeed conveyance guide B15b is connected to the exterior 1a of the apparatus main body.

  A fan A23 and a fan B24 are provided inside the exterior 1a of the apparatus main body, and the fan A23 and the fan B24 are disposed between the refeed conveyance guide A15a and the refeed conveyance guide B15b. A louver 18 is provided in the exterior 1a portion of the apparatus main body in a direction perpendicular to the sheet conveyance direction of the re-feed conveyance guide A15a so that air can pass therethrough. The fan A23 and the fan B24 are respectively disposed in the vicinity of the louver 18, and the air direction is set so that the fan A23 sucks in outside air and the fan B24 discharges into the outside air (see FIG. 6).

  The reversing path 16 includes a reversing path guide A 16 a and a reversing path guide B 16 b, and has the same configuration as the refeed conveyance path 15.

  The double-sided path 17 includes a double-sided path guide A 17 a and a double-sided path guide B 17 b, and has the same configuration as the refeed conveyance path 15.

Since the other parts are the same as those of the sheet feeding apparatus of the first embodiment, the same parts are denoted by the same reference numerals, and description thereof is omitted.
(Description of operation)
Next, the operation of the sheet cooling apparatus will be described.

  In the case of duplex copying, the sheet P is conveyed to the refeed conveyance path 15. The re-feed conveyance path 15 includes a re-feed conveyance guide A15a and a re-feed conveyance guide B15b made of heat insulating material. The air in the refeed conveyance path 15 is connected to the outside air by a louver 18 installed in the exterior 1a of the apparatus main body. Further, the outside air is sucked into the sheet refeeding conveyance path 15 and discharged by the fans A23 and B24. Therefore, the inside of the refeed conveyance path 15 is always at the same temperature as the outside air.

  When the sheet P is continuously copied on both sides, the temperature in the apparatus body gradually increases. However, since the refeed conveyance guide A15a and the refeed conveyance guide B15b are made of a heat insulating material, the air in the refeed conveyance path 15 is not affected by the temperature in the apparatus main body. Further, the distance between the refeed conveyance guide A15a and the refeed conveyance guide B15b is particularly short on the inlet side and the outlet side of the sheet P in the refeed conveyance path 15, and there is almost no influence of the temperature in the apparatus main body. I am doing so. Further, the outside air is sucked into and discharged from the sheet refeed conveyance path 15 by the fans A 23 and B 24, and fresh outside air is always taken into the sheet refeed conveyance path 15. Accordingly, the cooling efficiency of the sheet P in the refeed conveyance path 15 is improved.

  By the same operation in the reversing pass 16 and the double-sided pass 17, the cooling efficiency of the sheets in the reversing pass 16 and the double-sided pass 17 is improved.

  According to the above configuration, the cooling efficiency of the temperatures in the refeed conveyance path 15, the reversal path 16, and the double-sided path 17 is improved by the fan. Since 17 is made of a heat insulating material, the cooling efficiency does not change even if continuous double-sided copying is performed. Accordingly, the sheet is cooled while maintaining improved cooling efficiency.

<Embodiment 3>
(Description of configuration)
In FIG. 6, the fan A23 and the fan B24 arranged in the refeed conveyance path 15 are set so that the fan A23 sucks in the outside air and the fan B24 discharges into the outside air. Furthermore, the air volume of the fan A23 is set to be larger than the air volume of the fan B24.

  The reversing path 16 includes a reversing path guide A 16 a and a reversing path guide B 16 b, and has the same configuration as the refeed conveyance path 15.

  The double-sided path 17 includes a double-sided path guide A 17 a and a double-sided path guide B 17 b, and has the same configuration as the refeed conveyance path 15.

Since the other parts are the same as those of the sheet feeding apparatus of the first embodiment, the same parts are denoted by the same reference numerals, and description thereof is omitted.
(Description of operation)
Next, the operation of the sheet cooling apparatus will be described.

  In the case of duplex copying, the sheet P is conveyed to the refeed conveyance path 15. The re-feed conveyance path 15 includes a re-feed conveyance guide A15a and a re-feed conveyance guide B15b made of heat insulating material. The air in the refeed conveyance path 15 is connected to the outside air by a louver 18 installed in the exterior 1a of the apparatus main body. Further, the outside air is sucked into the sheet refeeding conveyance path 15 and discharged by the fans A23 and B24. Therefore, the inside of the refeed conveyance path 15 is always at the same temperature as the outside air.

  When the sheet P is continuously copied on both sides, the temperature in the apparatus body gradually increases. However, since the refeed conveyance guide A15a and the refeed conveyance guide B15b are made of a heat insulating material, the air in the refeed conveyance path 15 is not affected by the temperature in the apparatus main body. Further, the distance between the refeed conveyance guide A15a and the refeed conveyance guide B15b is particularly short on the inlet side and the outlet side of the sheet P in the refeed conveyance path 15, and there is almost no influence of the temperature in the apparatus main body. I am doing so. Further, the outside air is sucked into and discharged from the sheet refeed conveyance path 15 by the fans A 23 and B 24, and fresh outside air is always taken into the sheet refeed conveyance path 15.

  Further, since the air volume of the fan A23 is larger than that of the fan B24, the air volume sucked from the outside air is large, and the air volume discharged to the outside air is small. The inside of the refeed conveyance path 15 is positive pressure. The air in the refeed conveyance path 15 is blown out from the inlet and outlet of the refeed conveyance path 15 into the apparatus main body. Therefore, the temperature in the refeed conveyance path 15 is not affected by the temperature in the apparatus main body, and is always kept at the same temperature as the outside air. Even if the sheet P is fed continuously in the refeed conveyance path 15, the temperature in the refeed conveyance path 15 does not change with respect to the outside air, so that the same sheet cooling effect can always be obtained.

  By the same operation in the reversing path 16 and the double-sided path 17, the temperature in the reversing path 16 and the double-sided path 17 hardly changes with respect to the outside air.

  According to the above configuration, the temperatures in the refeed conveyance path 15, the reversing path 16, and the duplex path 17 are always the same as the outside air without increasing even if duplex copying is performed continuously, and the sheet P Is cooled with a more stable cooling effect.

  INDUSTRIAL APPLICABILITY The present invention is useful in an image forming apparatus such as a copying machine, a laser beam printer, and a facsimile, particularly for a sheet cooling apparatus that cools a sheet after heat-fixing a toner image transferred to the sheet.

It is sectional drawing of an image forming apparatus provided with the sheet | seat cooling device which concerns on Embodiment 1 of this invention. 1 is a schematic sectional view of an image forming apparatus. It is explanatory drawing of the sheet | seat cooling device which concerns on Embodiment 1 of this invention. It is explanatory drawing of the sheet | seat cooling device which concerns on Embodiment 1 of this invention. It is sectional drawing of an image forming apparatus provided with the sheet | seat cooling device which concerns on Embodiment 2 of this invention. It is explanatory drawing of the sheet | seat cooling device which concerns on Embodiment 2, 3 of this invention. It is sectional drawing of the conventional image forming apparatus.

Explanation of symbols

13 Fixing Device 15 Refeed Transport Dew 16 Reverse Pass 17 Double Sided Pass 23 Fan A
24 Fan B

Claims (7)

  In the image forming apparatus having the heat fixing device, the image forming apparatus includes a conveyance path that guides a sheet downstream of the heat fixing apparatus, and the conveyance path is configured by a member having a facing surface, and the member is configured by a heat insulating material. Or a sheet cooling device characterized by being covered with a heat insulating material.   The sheet cooling apparatus according to claim 1, wherein an opening is provided in a direction perpendicular to the sheet conveyance direction from the conveyance path formed by the opposed surfaces.   The sheet cooling apparatus according to claim 2, wherein the opening is connected to the conveyance path.   The sheet cooling apparatus according to claim 2, wherein the opening communicates with outside air.   The distance between the opposing surfaces is narrower than other portions at the entrance or exit of the sheet of the conveyance path constituted by the opposing surfaces, according to any one of claims 1 to 4. Sheet cooling device.   A blowing means is installed between the opposing surfaces to draw air between the opposing surfaces from outside air of the apparatus main body or to discharge air from between the opposing surfaces to the outside of the apparatus main body. The sheet cooling apparatus according to any one of claims 1 to 5.   7. The sheet cooling apparatus according to claim 6, wherein two or more of the air blowing means are installed, and the air volume of the air blowing means that sucks in from outside air is larger than the air volume of the air blowing means that discharges to the outside of the apparatus.

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