JP4935067B2 - Image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a multi-function machine having these functions, which employs an electrophotographic method, and more particularly, an image to be imaged such as a sheet on which a toner image is fixed by a fixing unit. The present invention relates to an image forming apparatus capable of transporting a forming member to an image forming unit again and forming an image on both sides of the image forming member.

JP 2003-5460 A JP 2004-157369 A JP 2004-170590 A

  In recent years, image forming apparatuses such as copiers and printers that employ this type of electrophotographic method have a great demand for noise reduction in addition to speeding up, downsizing, and energy saving. Among these requirements, in order to satisfy both the demands for downsizing and noise reduction, the above image forming apparatus is designed to increase the mounting density of functional components and prevent the sound inside the machine from leaking outside the machine. The countermeasure of reducing the opening part of is taken.

  However, in the image forming apparatus, when the opening of the apparatus main body is reduced, the temperature in the apparatus rises due to the heat from the fixing device that fixes the toner image on the paper, and the developing device In addition, the toner in the cleaning device has a problem of causing an adverse effect such as blocking.

  In particular, in an image forming apparatus capable of forming images on both sides of a sheet, when a sheet having a high temperature travels in a double-sided sheet conveyance path during double-sided printing, heat released from the sheet having a high temperature is generated in the apparatus. There has been a problem that image formation failure due to trapping, raising the temperature inside the apparatus, and raising the temperature of the image forming unit and malfunction due to toner blocking are likely to occur.

  Conventionally, in order to solve such problems, a technique for cooling a sheet in a double-sided sheet conveyance path is disclosed in Japanese Patent Application Laid-Open No. 2003-5460, Japanese Patent Application Laid-Open No. 2004-157369, or Japanese Patent Application Laid-Open No. 2004-170590. ing.

  An image forming apparatus according to the above-mentioned Japanese Patent Application Laid-Open No. 2003-5460 includes a sheet storage unit that stacks and stores a plurality of sheets, an image formation unit that forms a toner image on a sheet supplied from the sheet storage unit, A fixing unit that fixes the toner image formed on the sheet in the image forming unit by heat and pressure, and a double-sided conveyance for reversing and supplying the sheet on which the image is fixed on one side by the fixing unit to the image forming unit again. A heat absorbing portion of at least one heat pipe is disposed inside the bent portion of the sheet conveying path in the double-sided conveying portion, and absorbs the heat of the sheet applied by the fixing portion. It is comprised so that it may do.

  The image forming apparatus according to Japanese Patent Application Laid-Open No. 2004-157369 is a color image forming apparatus that forms an image on both sides of a sheet by electrophotography, and includes a heat fixing type fixing device and the color image forming apparatus. A temperature sensor for measuring the outside air temperature, a sheet conveying path for stackless automatic double-sided image formation, a sheet cooling means provided in the sheet conveying path, and a number of sheets for setting the continuous output number of images A setting unit and a control unit for controlling the sheet cooling unit, and the control unit is used for image transfer on the second surface based on the temperature information of the temperature sensor and the number setting information by the number setting unit. The sheet cooling means is controlled so that the temperature before transfer of the sheet to be transferred falls within the range of 30 to 35 ° C.

  Further, an image forming apparatus according to the above Japanese Patent Application Laid-Open No. 2004-170590 is an image forming apparatus that forms images on both sides of a sheet by an electrophotographic method, and includes a heat fixing type fixing device and an outside of the image forming apparatus. A temperature sensor for measuring the temperature of the paper, a paper conveyance path for performing stackless automatic double-sided image formation, and a paper cooling provided in a cooling area in the paper conveyance path for conveying the paper in a flat state and linearly Means, a number setting means for setting the continuous output number of images, and a control section for controlling the sheet cooling means, the control section by the temperature information of the temperature sensor and the number setting means Based on the number setting information, the sheet cooling means is controlled so that the temperature after cooling in the cooling area of the sheet used for image transfer on the second surface is 35 to 45 ° C. A.

  However, the conventional technique has the following problems. That is, in the case of the image forming apparatus according to Japanese Patent Application Laid-Open No. 2003-5460, Japanese Patent Application Laid-Open No. 2004-157369, or Japanese Patent Application Laid-Open No. 2004-170590, the inner side of the bent portion of the sheet conveyance path in the double-sided conveyance unit. The heat absorbing portion of at least one heat pipe is disposed so as to absorb the heat of the sheet applied by the fixing portion, or the temperature before transfer of the sheet used for image transfer on the second surface is set. The paper cooling means is controlled so as to fall within the range of 30 to 35 ° C., or the temperature after cooling in the cooling region of the paper used for image transfer on the second surface is 35 to 45 ° C. In addition, it is configured to control the paper cooling means, but it cannot cope with the increase in the ambient temperature due to the air heated to high temperature by the heat taken from the paper, and a sufficient effect cannot be obtained. Or By placing the sheet cooling means to the paper conveying path, apparatus or large-sized, has a problem that increases the cost.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to pass through the double-sided paper transport path without causing an increase in size and cost of the apparatus. An object of the present invention is to provide an image forming apparatus capable of preventing the temperature in the apparatus from rising due to the heat released from the sheet to be generated and causing malfunctions such as image formation defects and toner blocking.

That is, the invention described in claim 1 transfers the toner image formed by the image image forming unit onto the image forming member and fixes the toner image on the image forming member by at least heating. A fixing unit and an image forming member for re-image formation for conveying the image forming member fixed by the fixing unit to the image forming unit again and forming an image again on the image forming member. In an image forming apparatus having a conveyance path,
An image forming apparatus comprising: a heat blocking member for thermally blocking between the image forming member conveyance path for re-image formation and the image forming unit and the fixing unit .

According to a second aspect of the present invention, the toner image formed by the image forming unit is transferred onto the image forming member, and the toner image is fixed on the image forming member by heating at least the toner image. And the image forming member fixed by the fixing unit are conveyed again to the image forming unit, and the image forming member is conveyed for re-image formation to form an image again on the image forming member. In an image forming apparatus having a path,
The provided with a heat blocking member for blocking thermally between the target imaging member conveyance path wherein the image forming unit and the fixing means for re-imaging, for the re-imaging than the heat shield member to be An image forming apparatus comprising exhaust means for discharging air located in a space on the image forming member conveyance path side to the outside of the image forming apparatus.

  Further, according to a third aspect of the present invention, in the image according to the second aspect, the exhaust unit includes an exhaust fan and an exhaust opening provided on a surface of the image forming apparatus. Forming device.

  According to a fourth aspect of the present invention, the exhaust means includes a duct member that guides air located in a space closer to the image forming member conveyance path for re-image formation than the heat blocking member, and image formation Exhaust openings provided on the surface of the apparatus, and air located in the space on the image forming member conveyance path side for re-image formation through the duct member are passed from the exhaust openings to the outside of the image forming apparatus. The image forming apparatus according to claim 2, further comprising a blower fan for discharging the air.

  Furthermore, the invention described in claim 5 is the image forming apparatus according to claim 4, wherein the duct member also serves as the heat blocking member.

  According to a sixth aspect of the present invention, the blower fan is provided on an intake opening provided on the surface of the image forming apparatus, and external air is supplied from the intake opening to the image forming apparatus. By sucking the air inside, the air located in the space on the image forming member conveyance path side for re-image formation is discharged from the exhaust opening to the outside of the image forming apparatus through the duct member. The image forming apparatus according to claim 4, wherein the image forming apparatus is an image forming apparatus.

  Further, in the invention described in claim 7, the duct member has openings on both the exhaust opening provided on the surface of the image forming apparatus and the image forming member conveyance path side for the re-image formation. The image forming apparatus according to claim 4, further comprising:

  In the invention described in claim 8, the duct member includes an exhaust opening side provided on a surface of the image forming apparatus, an image forming member conveyance path side for the re-image formation, and the image formation. The image forming apparatus according to claim 4, further comprising an opening on an intake opening provided on a surface different from the exhaust opening of the apparatus.

  Furthermore, the invention described in claim 9 is characterized in that the blower fan introduces outside air closer to the image forming member conveyance path for re-image formation than the heat blocking member in the image forming apparatus. The image forming apparatus according to claim 4.

  The invention described in claim 10 is characterized in that the exhaust means operates only when image formation is performed again on the same image forming member. An image forming apparatus.

  Furthermore, the invention described in claim 11 is characterized in that the exhaust unit controls operation and non-operation based on a detection result of a temperature detection unit that detects a temperature of a predetermined part in the image forming apparatus. An image forming apparatus according to claim 1.

  According to the present invention, the temperature in the apparatus rises due to the heat released from the paper passing through the double-sided paper transport path without causing an increase in size and cost of the apparatus, resulting in poor image formation, toner blocking, etc. Thus, it is possible to provide an image forming apparatus capable of preventing the occurrence of the malfunction.

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

Embodiment 1
FIG. 2 is a schematic configuration diagram showing a medium-to-high speed monochrome multifunction peripheral employing an electrophotographic system as an image forming apparatus according to Embodiment 1 of the present invention. This monochrome multifunction device is provided with an image reading device, and is configured as an image forming device having functions as a copying machine, a printer, and a facsimile. Of course, the printer may be configured as a printer that forms an image based on image data output from the network.

  In FIG. 2, reference numeral 1 denotes a main body of a monochrome multifunction peripheral. An automatic document feeder (ADF) that automatically conveys originals (not shown) separated one by one is provided above the multifunction peripheral body 1. 2 and an image reading device 3 that reads an image of a document conveyed by the automatic document conveying device 2 is provided. The image reading device 3 illuminates a document (not shown) placed on a platen glass 4 with a light source 5, and reflects a reflected light image from the document from a full-rate mirror 6, half-rate mirrors 7 and 8, and an imaging lens 9. The image reading element 10 made of a CCD or the like is scanned and exposed through the reduction optical system 11 and the image reading element 10 reads an image of a document at a predetermined dot density (for example, 16 dots / mm). Has been.

  The document image read by the image reading device 3 is sent as image data to an image processing device 12 (IPS) provided inside the monochrome MFP main body 1, and the image processing device 12 uses the image data of the document. On the other hand, if necessary, predetermined image processing such as shading correction, position shift correction, gamma correction, and frame deletion is performed. In addition, the image processing apparatus 12 performs predetermined image processing on image data sent from a personal computer (not shown) as necessary.

  Then, the image data subjected to the predetermined image processing by the image processing device 12 is sent to a ROS (Raster Output Scanner) 13 as an image exposure means. In this ROS 13, a polygon mirror 14 or an f-θ lens (not shown) is used. The image exposure with the laser beam LB is performed according to the image data.

  By the way, as shown in FIG. 2, an image forming unit 100 for forming a toner image according to image data is disposed inside the monochrome MFP main body 1. A photosensitive drum 15 as an image carrier is provided at a predetermined process speed along the direction of the arrow, slightly to the left of the central portion in the multifunction machine main body 1. As the photosensitive drum 15, a conductive drum having a photosensitive layer made of OPC or the like on its surface is used. The photosensitive drum 15 is set to have a relatively large diameter. The image forming unit 100 includes a photosensitive drum 15, a scorotron 16 disposed around the photosensitive drum 15, a developing device 17, and a cleaning device 44.

  As shown in FIGS. 1 and 2, the surface of the photosensitive drum 15 is charged to a predetermined potential by two primary scorotrons 16 for primary charging, and then disposed on the upper portion of the photosensitive drum 15. An ROS (RasterOutputScanner) 13 performs image exposure according to the image data to form an electrostatic latent image. The electrostatic latent image formed on the surface of the photosensitive drum 15 is developed by the developing device 17 using a one-component developer composed only of toner or a two-component developer composed of toner and carrier, and image data. A toner image corresponding to the above is formed.

  In this embodiment, a large amount of image can be formed at a relatively high speed, and a toner cartridge having a large diameter for supplying toner, developer, and the like to the developing device 17 obliquely above the developing device 17. 18 is arranged. The toner cartridge 18 has a large capacity and can supply a large amount of toner. In addition, the toner cartridge 18 can be replaced even during an image forming operation. Can be printed without stopping the image forming operation.

  Further, as shown in FIG. 2, the toner image formed on the photosensitive drum 15 is a recording sheet as an image forming member of a desired size supplied from a plurality of paper feed cassettes 19 to 22 at a predetermined timing. The toner image is transferred onto a transfer roller 23 serving as a transfer unit and conveyed to a fixing device 25 serving as a fixing unit. The transfer roll 23 is disposed inside the conveyor belt 24, and is arranged in the vicinity of the upstream tension roll 26 among the three tension rolls 26, 27, 28 that stretch the conveyor belt 24. It is installed. The transfer roll 23, the conveyance belt 24, and the three stretching rolls 26, 27, and 28 are integrated into a unit, and constitute a transfer unit 80. As shown in FIG. 2, the recording paper 30 onto which the toner image is transferred from the photosensitive drum 15 is conveyed to the fixing device 25 by the conveying belt 24 while being sucked onto the conveying belt 24 by air pressure or the like. Is done.

  As shown in FIG. 2, the recording paper 30 is fed one by one from the paper feed cassettes 19 to 22 disposed inside the multifunction machine main body 1 by a paper feed roll 31, a retard roll 32 and a feed roll 33. In this state, the sheet is conveyed to the registration roll 35 via the conveyance roll 34. The recording paper 30 is conveyed to the transfer position of the photosensitive drum 15 in a state synchronized with the toner image formed on the photosensitive drum 15 by a registration roll 35 that is rotationally driven at a predetermined timing. After the toner image is transferred by the transfer roll 23, the toner image is conveyed to the fixing device 25.

  Among the plurality of paper feed cassettes 19 to 22, in particular, the paper feed cassettes 19 and 20 are large-capacity paper feed cassettes, and can feed thousands of recording sheets 30 continuously. It has become.

Further, as shown in FIG. 2, the recording paper 30 on which the toner image is fixed by the fixing device 25 is not provided in the side surface of the multifunction machine main body 1 by the discharge roll 36 in the case of single-sided printing. It is discharged onto the discharge tray. In the case of double-sided printing of the recording paper 30, that is, in the case of re-image formation in which an image is formed again on the back surface of the recording paper 30, the recording paper 30 with the image formed on one side is directly ejected by the ejection roll 36. Instead of discharging upward, the transfer direction of the recording paper 30 is switched downward by the switching gate 37 to the paper transport reversing section 41 having the reversing roll 40 via the tri roll 39 in which the three rolls 38 are in contact with each other. And once introduced. The recording paper 30 introduced into the paper conveyance reversing unit 41 is sent out by reversing the rotation direction of the reversing roll 40, and the conveyance direction is automatically reset by the switching gate 42 made of Mylar film or the like. It is switched to the sheet conveying path 60 for duplex printing as the image forming member conveying path for image formation, and the front and back are reversed through the sheet conveying path 60 for duplex printing, and again, It is conveyed to the registration roll 35 and an image is formed on the back surface of the recording paper 30.
Note that a plurality of transport rollers 61 for transporting paper are arranged in the paper transport path 60 for duplex printing.

  In FIG. 2, reference numeral 81 denotes a cleaning device including a cleaning blade 82 for cleaning the surface of the photosensitive drum 15. In FIG. 2, reference numeral 83 denotes an auxiliary charging corotron, and 84 denotes a pre-cleaning corotron.

  FIG. 3 is a cross-sectional configuration diagram showing the fixing device of the monochrome multifunction peripheral. The fixing device is configured to fix an unfixed toner image on the recording paper by heating at least the recording paper.

  As shown in FIG. 3, the fixing device 25 includes a heating roll 43 serving as a heating rotating body and a pressure roll 44 serving as a pressing rotating body as a pair of rotating bodies that are pressed against each other to form a nip portion N. It has. As will be described later, the heating roll 43 and the pressure roll 44 are disposed so as to be switchable between a pressure contact state in which they are pressed against each other at a predetermined pressure and a separated state in which they are separated. The heating roll 43 includes a cored bar 45 formed in a cylindrical shape with a metal such as stainless steel or aluminum, and a heat-resistant elastic body layer 46 made of a heat-resistant silicone rubber or the like coated on the surface of the cored bar 45 thickly. And a release layer 47 made of tetrafluoroethylene, PFA or the like coated on the surface of the heat-resistant elastic layer 46. Further, inside the heating roll 43, three halogen lamps 48 are arranged as heating sources. The heating roll 48 is heated by the halogen lamp 48 from the inside, and the surface temperature of the heating roll 48 is increased. The surface temperature is detected by a temperature detection sensor 49 so that the temperature of the halogen lamp 48 becomes a predetermined temperature, and energization to the halogen lamp 48 is controlled.

  Further, on the surface of the heating roll 43, a cleaning oil-impregnated web 50 impregnated with a release agent such as silicon oil is removed in order to remove foreign matters such as toner adhering to the surface of the heating roll 43. Abutted by a roll 51. The cleaning web 50 is supplied from a web supply roll 52 and is taken up at a predetermined timing by a web take-up roll 53.

  On the other hand, the pressure roll 44 is made of a heat-resistant core made of a metal core 54 formed of a metal such as stainless steel or aluminum, and a heat-resistant silicone rubber coated on the surface of the metal core 54 relatively thickly. The elastic body layer 55 includes a release layer 56 made of tetrafluoroethylene, PFA, or the like coated on the surface of the heat resistant elastic body layer 55. In FIG. 3, reference numeral 58 indicates a housing of the fixing device 25.

  Further, a conveyance roll 57 for discharging the recording paper 30 fixed by the fixing device 25 is disposed at the exit of the fixing device 25, and the recording paper 30 discharged by the conveyance roll 57 is As shown in FIG. 2, the sheet is discharged onto the discharge tray by the discharge roll 36 via the switching gate 37, or when double-sided printing, the conveyance direction is switched downward by the switching gate 37 to the tri-roll 39. It is designed to be transported.

  By the way, in this embodiment, a fixing unit that transfers a toner image formed by an image forming unit onto an image forming member and fixes the toner image on the image forming member by at least heating, and An image forming member transport path for re-image formation for transporting the image forming member fixed by the fixing unit to the image forming unit again and forming an image on the image forming member again. The forming apparatus is configured to include a heat blocking member that thermally blocks at least the image forming member conveyance path for re-image formation and the image forming unit.

  That is, in the monochrome multifunction device, as shown in FIG. 1, between the sheet conveyance path 60 for duplex printing as the image forming member conveyance path for re-image formation, and between the image forming unit 100 and the fixing device 25. A heat blocking member 62 that thermally blocks the sheet is provided so as to partition between the sheet conveying path 60 for duplex printing, the image forming unit 100, and the fixing device 25. The heat blocking member 60 blocks the heat of the recording sheet 30 passing through the sheet conveying path 60 for double-sided printing from being transmitted to the image forming unit 100 and the fixing device 25 side by heat conduction (convection) via air. Thus, the temperature of the image forming unit 100, in particular, the transfer unit 80 and the cleaning device 81 is suppressed from rising. As the material of the heat blocking member 62, a vacuum heat insulating material, a glass wool material, or the like is used. In addition to the high heat insulating material, a synthetic resin plate made of ABS resin or the like, a metal plate made of iron, aluminum, stainless steel, or the like can be used.

  In this embodiment, as the heat blocking member 62, a heat insulating plate having a thickness of 5 mm formed by hardening glass wool material into a plate shape is used.

  The heat blocking member 62 is inside the monochrome MFP main body 1, and one end of the heat blocking member 62 is between the sheet transport path 60 for duplex printing, the image forming unit 100, and the fixing device 25. The other end of the heat shield member 62 is disposed horizontally from the lower side of the fixing device 25 to the lower side of the fixing device 25, and both ends of the heat blocking member 62 are extended to the position of the sheet conveyance path 60 for double-sided printing.

  Note that the heat blocking member 62 is not limited to be disposed horizontally, but may be disposed to be inclined so that the duct member side becomes higher, as will be described later, when a duct member is disposed.

  In the above-described configuration, in the monochrome MFP according to the first embodiment, heat released from the paper passing through the double-sided paper transport path without causing an increase in size and cost of the apparatus as follows. As a result, it is possible to prevent the temperature in the apparatus from rising and malfunctions such as image formation failure and toner blocking.

  That is, in the monochrome multifunction device, as shown in FIG. 2, when printing an image on both sides of the recording paper 30 as an image forming member, the recording paper 30 on which the image is formed on one side by the image forming unit 100, The recording paper 30 that has undergone the fixing process by the fixing device 25 is not directly discharged onto a paper discharge tray (not shown) by the discharge roll 36, but is switched downward by the switching gate 37, and the paper transport reversing unit is connected via the tri roll 39. 41. After that, the recording paper 30 introduced into the paper transport reversing unit 41 is reversed in the transport direction by the reversing roll 40 of the paper transport reversing unit 41 and the front and back of the recording paper 30 are reversed. Then, the sheet is conveyed again to the image forming unit 100 through the sheet conveyance path 60.

  At that time, the recording paper 30 heated and heated by passing through the fixing device 25 is used for double-sided printing due to the heat of the recording paper 30 when passing through the paper transport path 60 for double-sided printing. The air positioned around the paper transport path 60 is heated, and the heated air tends to move upward from the paper transport path 60 for double-sided printing by convection, but for the double-sided printing. A heat blocking member 62 is disposed above the paper transport path 60. Therefore, the air heated by the recording paper 30 passing through the paper conveyance path 60 for double-sided printing is prevented from moving to the image forming unit 100 and the fixing device 25 side by the heat blocking member 62, and the double-sided printing is performed. It is possible to suppress or prevent the temperature in the vicinity of the transfer unit 80, the cleaning device 81, and the fixing device 25 of the image forming unit 100 from being increased by the heat of the recording paper 30 passing through the time paper transport path 60.

  As described above, in the monochrome multifunction peripheral according to the first embodiment, the heat blocking member 62 is provided between the paper conveyance path 60 for double-sided printing, the image forming unit 100, and the fixing device 25. As a result, it is possible to suppress or prevent the temperature of the image forming unit 100 from rising. Therefore, the temperature in the apparatus rises, and image formation defects such as toner image transfer defects in the transfer unit 80, the developing device 17 or the like. It is possible to prevent toner blocking or the like that the toner in the cleaning device 81 blocks, and to prevent malfunction.

  Further, in the case of the monochrome multifunction device, it is only necessary to provide the heat blocking member 62 between the paper conveyance path 60 for duplex printing, the image forming unit 100, and the fixing device 25. Since there is no need to provide a sheet cooling means, the apparatus is not increased in size and cost.

Experimental example 1
Next, in order to confirm the effect of the present invention, the inventors made a prototype of a monochrome multifunction device as shown in FIG. 1 and put it on an A4 size recording paper 30 (P paper manufactured by Fuji Xerox Co., Ltd.) every minute. An experiment was conducted in which double-sided printing was performed continuously for 2 hours by feeding 55 sheets, and the temperature on the photosensitive drum cleaning device and the transfer unit fixing device side was measured. The surface temperature of the heating roll 43 of the fixing device 25 was set to 200 ° C. and the fixing process was performed.

  As a result, the temperature of the cleaning device 81 of the photosensitive drum 15 and the temperature of the fixing device 25 of the transfer unit 80 can be suppressed to 48 ° C. at an environmental temperature of 32 ° C., and toner softening in the cleaning device 44 is observed. Thus, it was found that image formation can be performed stably.

  By the way, the toner used in the image forming apparatus such as the above-mentioned monochrome multifunction device is integrated by adding carbon black for black or a color pigment to a resin such as polyester or acrylic, and is molded into a powder of about 3 to 10 μm in diameter. It is a thing. The softening and melting characteristics of the toner due to heat largely depend on the characteristics of the base resin, but the characteristics in the image forming apparatus as an aggregate of powder do not necessarily match those of the resin. Generally, the blocking temperature due to softening in the image carrier cleaning device in the toner image forming apparatus using the resin is 50 to 60 ° C. The toner used in this experimental example begins to soften when it exceeds 50 ° C. when viewed at the frame temperature of the image carrier cleaning device, and has a blocking effect when it exceeds 55 ° C.

Comparative Example 1
In order to confirm the effect of the present invention, the inventors removed the heat blocking member 62 as a comparative example in a monochrome multifunction device as shown in FIG. 1, and A4 size recording paper 30 (P paper manufactured by Fuji Xerox Co., Ltd.). 2), an experiment was conducted in which double-sided printing was continuously performed for 2 hours at a feeding rate of 55 sheets per minute, and the temperatures of the cleaning device 81 of the photosensitive drum 15 and the fixing device 25 side of the transfer unit 80 were measured. The surface temperature of the heating roll 43 of the fixing device 25 was set to 200 ° C. and the fixing process was performed.

  Also, for reference, single-sided printing is performed continuously for 2 hours at 55 sheets per minute on A4 size recording paper 30 (P paper manufactured by Fuji Xerox Co., Ltd.), and a photosensitive drum cleaning device and transfer unit. An experiment was conducted to measure the temperature of the fixing device side.

  As a result, the temperature on the side of the fixing device 25 of the cleaning device 81 of the photosensitive drum 15 and the transfer unit 80 rises by 5 to 8 ° C. compared to the time of single-side printing, and reaches a maximum of 54 ° C. at an environmental temperature of 32 ° C. The toner in the cleaning device 44 began to soften and began to interfere with image formation.

Embodiment 2
FIG. 4 shows a second embodiment of the present invention. The same reference numerals are given to the same parts as those in the first embodiment, and the second embodiment is formed by an image forming unit. A fixing means for transferring the toner image onto the image forming member and fixing the toner image on the image forming member by at least heating; and an image forming member fixed by the fixing means again, In an image forming apparatus having an image forming member transport path for re-image formation for transporting to the image forming unit and forming an image again on the image forming member, at least image forming for re-image formation A heat blocking member is provided for thermally blocking between the member transport path and the image forming unit, and an empty space located in a space closer to the image forming member transport path for re-image formation than the heat blocking member. It is configured to include an exhaust means for discharging to the outside of the image forming apparatus.

  Further, in the second embodiment, the exhaust unit includes an exhaust fan and an exhaust opening provided on the surface of the image forming apparatus.

  Further, the second embodiment is configured such that the exhaust unit operates only when image formation is performed again on the same image-formed member.

  In the second embodiment, the exhaust unit may be configured to control operation and non-operation based on a detection result of a temperature detection unit that detects the temperature of a predetermined part in the image forming apparatus. good.

  That is, in the second embodiment, as shown in FIGS. 4 and 5, a heat blocking member 62 that thermally blocks the sheet conveyance path 60 for double-sided printing from the image forming unit 100 and the fixing device 25. And an exhaust means 63 for discharging the air located in the space S on the side of the paper conveyance path 60 for duplex printing to the outside of the monochrome multifunction printer main body 1 with respect to the heat blocking member 62.

  As shown in FIG. 5, the exhaust means 63, on the back side of the monochrome multifunction printer main body 1, removes air located in a space closer to the paper conveyance path 60 for duplex printing than the heat blocking member 62. An exhaust fan 64 is provided as a blower fan that discharges outside the machine body 1.

  The exhaust fan 64 is controlled to operate only during double-sided printing and to be inactive during single-sided printing. However, even during double-sided printing, the temperatures of the cleaning device 81 for the photosensitive drum 15 and the fixing device 25 side of the transfer unit 80 are detected by a temperature sensor (not shown), and the cleaning device for the photosensitive drum is detected. The exhaust fan 64 may be controlled to operate only when the temperature on the fixing device side of the transfer unit becomes a predetermined temperature (for example, 40 ° C.) or higher.

  As described above, in the second embodiment, the heat blocking member 62 is provided between the sheet conveyance path 60 for duplex printing, the image forming unit 100, and the fixing device 25, so that the temperature of the image forming unit is increased. Of course, it is possible to suppress or prevent the air from rising, and the air located in the space S on the paper transport path 60 side for duplex printing on the back side of the monochrome MFP main body 1 rather than the heat blocking member 62. Is provided in the space on the side of the sheet conveyance path 60 for double-sided printing with respect to the heat blocking member 62. By actively exhausting the air out of the apparatus by the exhaust fan 64, it is possible to further suppress or prevent the temperature of the image forming unit and the like from rising.

Experimental example 2
Next, in order to confirm the effect of the present invention, the inventors made a prototype of a monochrome multifunction device as shown in FIG. 4 and put it on an A4 size recording paper 30 (P paper manufactured by Fuji Xerox Co., Ltd.) every minute. An experiment was conducted in which double-sided printing was performed continuously for 2 hours by feeding 55 sheets, and the temperatures of the cleaning device 81 of the photosensitive drum 15 and the fixing device 25 side of the transfer unit 80 were measured. The surface temperature of the heating roll 43 of the fixing device 25 was set to 200 ° C. and the fixing process was performed.

  As a result, the temperatures of the cleaning device 81 of the photosensitive drum 15 and the fixing device 25 of the transfer unit 80 can be suppressed to a maximum of 45 ° C. at an environmental temperature of 32 ° C., and toner softening in the cleaning device 44 is observed. Thus, it was found that image formation can be performed stably. The maximum temperature of 45 ° C. is only 3 ° C. lower than 48 ° C. in Experimental Example 1, but the temperature on the fixing device 25 side of the cleaning device 81 of the photosensitive drum 15 and the transfer unit 80 is 1 ° C. The lower the effect on the image forming process is improved, it can be said that the improvement effect is large.

  Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

Embodiment 3
FIG. 6 shows a third embodiment of the present invention. The same reference numerals are given to the same parts as those in the first embodiment, and in this third embodiment, the exhaust means includes the exhaust means. A duct member that guides air positioned in a space closer to the image forming member conveyance path for re-image formation than the heat blocking member, an exhaust opening provided on the surface of the image forming apparatus, and the duct member And a blower fan for discharging air positioned in the space on the image forming member conveyance path side for re-image formation to the outside of the image forming apparatus from the exhaust opening.

  Moreover, in this Embodiment 3, the said duct member is comprised so that it may serve as the said heat-shielding member.

  Further, in the third embodiment, the blower fan is provided on the intake opening provided on the surface of the image forming apparatus, and external air is sucked into the image forming apparatus from the intake opening. Thus, the air positioned in the space on the image forming member conveyance path side for re-image formation is discharged from the exhaust opening to the outside of the image forming apparatus via the duct member. Yes.

  In the third embodiment, the duct member includes an exhaust opening provided on the surface of the image forming apparatus, an image forming member conveyance path side for the re-image formation, and an exhaust of the image forming apparatus. The opening is provided on the side of the intake opening provided on the surface different from the opening for use.

  Further, in the third embodiment, the blower fan is configured to introduce the outside air to the image forming member conveyance path side for re-image formation rather than the heat blocking member in the image forming apparatus.

  That is, in the third embodiment, as shown in FIG. 6, the gap between the transfer unit 80 and the fixing device 25 is positioned in the space S on the side of the sheet conveyance path 60 for duplex printing than the heat blocking member 62. A duct member 70 that guides air to be used is disposed, and the duct member also serves as a part of the heat blocking member 62.

  That is, the heat blocking member 62 is provided with an opening 71 at a position corresponding to the duct member 70, and the opening communicates with the inside of the duct member 70. Further, the duct member 70 constitutes a part of the heat blocking member 62 and also functions to thermally block between the transfer unit 80 and the fixing device 25.

  Further, in the third embodiment, as shown in FIG. 7, an intake opening 72 is provided on the front surface of the monochrome multifunction peripheral body 1, and the intake opening 72 is formed of a duct member. 70 communicates with the inside. Further, a blower fan 73 for introducing outside air to the side of the sheet conveyance path 60 for duplex printing than the heat blocking member 62 in the monochrome MFP main body 1 is disposed on the side of the intake opening 72 of the duct member 70. Has been. Further, an exhaust opening 74 communicating with the inside of the duct member 70 is provided on the surface on the back side of the monochrome MFP main body 1.

  As described above, in Embodiment 3, the space between the transfer unit 80 and the fixing device 25 can be thermally blocked by the duct member 70, and outside air is introduced into the duct member 70 by the blower fan 73. The air heated by the recording paper 30 passing through the paper conveyance path 60 for double-sided printing located below the heat shut-off member 62 and the outside room temperature air introduced into the duct member 70 are used as a duct. It can be discharged from the exhaust opening 74 of the member 70 to the outside, and it is possible to further suppress or prevent the temperature of the image forming unit 100 and the like from rising.

  In the third embodiment as well, the blower fan 73 is controlled to operate only during double-sided printing and to be inactive during single-sided printing. However, even during duplex printing, the temperature of the cleaning device 81 for the photosensitive drum 15 and the temperature on the fixing device 25 side of the transfer unit 80 are detected by a temperature sensor as a detection unit (not shown) to clean the photosensitive drum 15. The blower fan 73 may be controlled to operate only when the temperature on the fixing device 25 side of the apparatus 81 and the transfer unit 80 is equal to or higher than a predetermined temperature (for example, 40 ° C.).

Experimental example 3
Next, in order to confirm the effect of the present invention, the inventors made a prototype of a monochrome multifunction device as shown in FIG. 6 and put it on an A4 size recording paper 30 (P paper manufactured by Fuji Xerox Co., Ltd.) every minute. An experiment was conducted in which double-sided printing was performed continuously for 2 hours by feeding 55 sheets, and the temperatures of the cleaning device 81 of the photosensitive drum 15 and the fixing device 25 side of the transfer unit 80 were measured. The surface temperature of the heating roll 43 of the fixing device 25 was set to 200 ° C. and the fixing process was performed.

  As a result, the temperature of the cleaning device 81 for the photosensitive drum 15 and the temperature on the fixing device 25 side of the transfer unit 80 can be suppressed to a maximum of 45 ° C. at an environmental temperature of 32 ° C., and toner softening is observed in the cleaning device. Thus, it was found that image formation can be performed stably.

  Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

FIG. 1 is a block diagram showing a main part of a monochrome multifunction peripheral as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a monochrome multifunction machine as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional configuration diagram illustrating the fixing device. FIG. 4 is a block diagram showing a main part of a monochrome multifunction peripheral as an image forming apparatus according to Embodiment 2 of the present invention. FIG. 5 is a schematic configuration diagram showing a main part of a monochrome multifunction peripheral as an image forming apparatus according to Embodiment 2 of the present invention. FIG. 6 is a block diagram showing a main part of a monochrome multifunction peripheral as an image forming apparatus according to Embodiment 3 of the present invention. FIG. 7 is a schematic configuration diagram showing a main part of a monochrome multifunction peripheral as an image forming apparatus according to Embodiment 3 of the present invention.

Explanation of symbols

  100: Image forming unit, 25: Fixing device, 30: Recording paper, 60: Paper transport path for double-sided printing, 62: Heat blocking member.

Claims (11)

A fixing unit configured to transfer the toner image formed by the image image forming unit onto the image forming member and fix the toner image on the image forming member by at least heating; and a fixing unit fixed by the fixing unit. In the image forming apparatus having an image forming member transport path for re-image formation for transporting the image forming member again to the image forming unit and forming an image again on the image forming member.
An image forming apparatus comprising: a heat blocking member that thermally blocks between the image forming member conveyance path for re-image formation and the image forming unit and the fixing unit . A fixing unit that transfers a toner image formed by the image forming unit onto an image forming member and fixes the toner image on the image forming member by at least heating; and an image to be fixed by the fixing unit. In the image forming apparatus having an image forming member transport path for re-image formation for transporting the forming member again to the image forming unit and forming an image on the image forming member again.
The provided with a heat blocking member for blocking thermally between the target imaging member conveyance path wherein the image forming unit and the fixing means for re-imaging, for the re-imaging than the heat shield member to be An image forming apparatus comprising exhaust means for discharging air located in a space on the image forming member conveyance path side to the outside of the image forming apparatus. The image forming apparatus according to claim 2, wherein the exhaust unit includes an exhaust fan and an exhaust opening provided on a surface of the image forming apparatus. The exhaust means includes a duct member that guides air located in a space closer to the image forming member conveyance path for re-image formation than the heat blocking member, an exhaust opening provided on a surface of the image forming apparatus, A blower fan for discharging air positioned in the space on the image forming member conveyance path side for re-image formation through the duct member to the outside of the image forming apparatus from the exhaust opening. The image forming apparatus according to claim 2. The image forming apparatus according to claim 4, wherein the duct member also serves as the heat blocking member. The blower fan is provided on the side of the intake opening provided on the surface of the image forming apparatus. By sucking outside air into the image forming apparatus from the intake opening, the air blowing fan is interposed through the duct member. 5. The image forming apparatus according to claim 4, wherein air positioned in a space on the image forming member conveyance path side for re-image formation is discharged from the exhaust opening to the outside of the image forming apparatus. . The duct member includes openings on both an exhaust opening provided on a surface of the image forming apparatus and an image forming member conveyance path side for the re-image formation. 5. The image forming apparatus according to 4. The duct member is provided on a surface different from the exhaust opening side provided on the surface of the image forming apparatus, the image forming member conveyance path side for the re-image formation, and the exhaust opening of the image forming apparatus. The image forming apparatus according to claim 4, further comprising an opening on the side of the intake opening. The image forming apparatus according to claim 4, wherein the blower fan introduces outside air closer to the image forming member conveyance path for re-image formation than the heat blocking member in the image forming apparatus. The image forming apparatus according to claim 1, wherein the exhaust unit operates only when image formation is performed again on the same image forming member. The exhaust unit controls operation and non-operation based on a detection result of a temperature detection unit that detects a temperature of a predetermined part in the image forming apparatus. Image forming apparatus.

Images