JP2012103690A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable efficiently cooling fixing means and a recording medium after fixation with a simple structure.SOLUTION: An image forming device is configured such that a branched air duct 84, which branches from an upstream side in a blowing direction of an opening and closing shutter 83 and extends toward a paper delivery area 85 of fixing means 8, is provided in an air duct 82 extending from a blower fan 81 to the fixing means 8, the fixing means 8 and the recording medium after fixation are cooled by the common blower fan 81 with a simple structure by operating the opening and closing shutter 83 and the blower fan 81 based on the size of a recording medium and temperature of the paper delivery area 85, and thus, both the fixing means and the recording medium are efficiently cooled by the operation of the opening and closing shutter 83.

Description

  The present invention relates to an image forming apparatus including a cooling unit that cools a fixing unit that fixes an image on a recording medium.

  In general, in an image forming apparatus such as a copying machine or a printer employing an electrophotographic method or an electrostatic recording method, a toner image corresponding to image information is formed on a recording medium such as a cut sheet by a transfer method or a direct method. The recording medium is introduced into a fixing device (fixing means) to fix the toner image as a fixed image on the surface, and then discharged out of the apparatus as an image formed product (copy, print). Yes. As a fixing device used at this time, a heat fixing method in which heat and pressure are applied to an unfixed image and a recording medium on a recording medium to perform penetration and fixing is generally used.

  As described above, the fixing device (fixing unit) fixes the toner image on the recording medium and then discharges the recording medium to the discharge area. However, as described above, when the thermal fixing method is adopted. However, there is a tendency that the non-sheet passing area with respect to the sheet passing area of the small-sized recording medium, for example, both ends in the longitudinal direction of the fixing unit is heated to have a difference in heat distribution with the central portion. The paper region is cooled by fixing cooling means (see Patent Document 1). For example, as shown in FIG. 19, a blower duct 101 constituting a blower guide means extends from a blower fan 100 provided as a fixing cooling means to a fixing device (fixing means) 102. Necessary cooling action is obtained by opening and closing by the operation of the opening and closing shutter 103. At this time, one blower fan 100 is arranged at each of both ends in the longitudinal direction of the heat fixing roller 102 a provided in the fixing device 102, and the recording medium to be passed is a small size and the paper passing through the fixing device 102. When a non-sheet passing area is generated in the area, the opening / closing shutter 103 is opened in accordance with the size of the recording medium, whereby cooling air is sent to the non-sheet passing area where the small size recording medium on both ends in the longitudinal direction does not pass. It is like that.

  On the other hand, the recording medium immediately after being discharged from the fixing device (fixing means) 102 to the discharge area is easy to store heat. For example, when a large amount of recording medium is stacked in the discharge area, the recording medium is solidified once after fixing. There is a possibility that a phenomenon in which the toner exceeds the melting point again due to heat accumulated by continuous paper passing and the overlapping recording media stick to each other with the toner. For this reason, a blower fan 104 is also provided in the paper discharge area of the fixing unit 102, and the recording medium in the paper discharge area is generally cooled by driving the blower fan 104.

  However, as described above, in the conventional image forming apparatus, in addition to the blower fan 100 for cooling the fixing device (fixing unit) 102, the blower fan 104 for cooling the recording medium discharged from the fixing unit 102 is provided. Since it is provided, there is a problem in that it is difficult to reduce the size and cost by making the entire apparatus larger or more complicated.

JP 2003-76209 A

  The present invention has been made in this background, and an object of the present invention is to provide an image forming apparatus capable of efficiently cooling the fixing unit and the recording medium after fixing with a simple configuration. Is to provide.

  In order to achieve the above object, in the present invention, fixing means for fixing a toner image on a recording medium, fixing cooling means for cooling the fixing means, and operations relating to image formation are performed on these fixing means and fixing cooling means. An image forming control unit that includes a blowing fan, a blowing guide unit having a blowing duct extending from the blowing fan to the fixing unit, and the blowing guide unit. In the image forming apparatus provided with an opening / closing shutter that opens and closes the air duct, the air duct is provided with a branch air duct that extends from the fixing unit toward the paper discharge area downstream in the recording medium conveyance direction, The image forming control means is configured to operate the open / close shutter and the blower fan based on the size of the recording medium and the temperature of the paper discharge area. It is.

  In the present invention, a fixing unit that fixes a toner image on a recording medium, a paper discharge transport unit that discharges the recording medium to a paper discharge region through a paper discharge transport path, and a fixing cooling unit that cools the fixing unit. And an image formation control means for causing the fixing means and the fixing cooling means to perform operations relating to image formation, the fixing cooling means extending from the blower fan to the fixing means. In the image forming apparatus comprising a blowing guide unit having a blowing duct to be opened and an open / close shutter for opening and closing the blowing duct of the blowing guide unit, the blowing duct has a discharge on the downstream side in the recording medium conveyance direction from the fixing unit. A branch air duct having an exhaust opening that extends toward the paper area and blows air to the paper discharge area is provided. It is provided so as to blow air substantially parallel to the medium discharge direction, and is formed so as to be inclined toward the center side in the paper width direction of the recording medium. A configuration is adopted in which the opening / closing shutter and the blower fan are operated based on the size of the recording medium.

  According to such a configuration of the present invention, the cooling of the fixing unit and the cooling of the recording medium after fixing are performed with a simple configuration by the common blower fan, and both cooling operations are performed by the operation of the open / close shutter. Is being done efficiently.

  In the present invention, the blower fans are respectively disposed at both ends in the paper width direction orthogonal to the discharge direction of the recording medium, and the outlets of the branch air ducts are substantially parallel to the discharge direction of the recording medium. It is desirable that it be formed to incline toward the center side in the paper width direction.

  By adopting such a configuration, the air blown from the branch air duct to the paper discharge area causes the recording medium to pass wind in front of the discharge port in the stacking process after the discharge of the recording medium. It can be applied to the recording medium by being formed so as to be inclined toward the center in the paper width direction.

  Further, the image formation control means in the present invention may be configured to close the open / close shutter and operate the blower fan when the size of the recording medium and the temperature of the paper discharge area are larger than a reference value. It is.

  In the present invention, the discharge opening of the branch air duct is above the stack surface of the recording medium stacked in the discharge area, and the discharge conveyance is performed so as to discharge the recording medium. It is desirable that the sheet is disposed below the sheet discharge roller provided in the path.

  By adopting such a configuration, the recording medium that is sent from the paper discharge roller provided in the paper discharge conveyance path and is to be stacked in the paper discharge area is cooled by the air blown from the exhaust opening of the branch air duct. In particular, when both the front and back surfaces of the recording medium are cooled, a good cooling action can be obtained.

  In the present invention, at least one transport roller for transporting the recording medium is disposed in the paper discharge transport path, and the branch air duct sends air to the transport roller to cool the transport roller. It is desirable to be arranged so as to.

  If such a configuration is adopted, the conveyance rollers provided in the paper discharge conveyance path are cooled by the air blown from the exhaust opening of the branch air duct, and as a result, the cooling of the recording medium is more efficient. Done.

  In the present invention, the discharge conveyance path is provided so as to extend in a plurality of branches, and a plurality of discharge openings are provided corresponding to each of the plurality of discharge conveyance paths. In addition, by rotating a flapper disposed at a branch position of the plurality of paper discharge paths, the paper discharge path of the recording medium to be conveyed is selected and switched. The branch air ducts are provided so as to extend along a plurality of paper discharge conveyance paths, and exhaust openings of the branch air ducts are respectively provided below the plurality of paper discharge ports. And an air path switching guide for switching the air path of the paper discharge path so as to select an exhaust opening through which air is blown, and the air path switching guide is used to rotate the flapper. In conjunction Performed Toggles operation, is configured to blow from the exhaust opening corresponding to the discharge port of the discharge path which is selected by the rotation of the flapper is performed.

  By adopting such a configuration, when the recording medium is selectively conveyed through a plurality of paper discharge conveyance paths, the branch air duct is only provided to the paper discharge conveyance path that is actually conveyed. Blowing from the exhaust opening is performed, and the recording medium is further efficiently cooled without waste.

  As described above, the present invention provides a blower duct that extends from the blower fan to the fixing unit, and a branched blower duct that branches from the upstream side in the blowing direction of the open / close shutter and extends toward the discharge region of the fixing unit, By operating the open / close shutter and the blower fan based on the size of the recording medium and the temperature of the paper discharge area, the fixing unit and the fixed recording medium are cooled by a common blower fan with a simple configuration. In addition, since both the cooling is efficiently performed by the operation of the opening / closing shutter, the fixing unit and the recording medium after the fixing can be efficiently cooled with a simple configuration, and image formation is performed. The reliability of the apparatus can be improved at a low cost.

  Further, according to the present invention, the exhaust opening of the branch air duct that extends toward the discharge area downstream of the fixing unit in the recording medium conveyance direction and blows air to the discharge area is substantially parallel to the discharge direction of the recording medium. Is formed so as to be inclined toward the central side in the paper width direction of the recording medium, so that the air is blown from the branch air duct to the discharge area almost evenly with respect to the recording medium. Therefore, the fixing unit and the recording medium after fixing can be cooled more efficiently and reliably.

1 is a longitudinal cross-sectional explanatory diagram showing an internal schematic structure of a copying machine as an example of an image forming apparatus to which the present invention is applied. FIG. 2 is a longitudinal sectional explanatory view showing an internal schematic structure of a fixing unit (fixing apparatus) and a cooling unit used in the copying machine shown in FIG. 1 according to the first embodiment of the present invention. FIG. 3 is an external perspective view illustrating an arrangement relationship between a blower duct and a blower fan provided in the fixing unit (fixing device) illustrated in FIG. 2. FIG. 4 is an external perspective explanatory view showing an opening / closing shutter provided in the fixing unit (fixing device) shown in FIGS. 2 and 3. FIG. 3 is a flowchart illustrating a control operation of an image formation control unit (controller) according to the first embodiment of the present invention. It is perspective explanatory drawing showing the state which removed the ventilation fan from the ventilation duct shown by FIG. FIG. 7 is an explanatory perspective view illustrating a cross-sectional shape of a blower duct with respect to the aa line in FIGS. 1 and 6. It is a perspective explanatory view showing the comparative example with the cross-sectional shape of the ventilation duct shown by FIG. It is a flowchart showing the operation control operation | movement of the opening-and-closing shutter and the ventilation fan by the image formation control means concerning one Embodiment of this invention. It is a longitudinal section explanatory view showing operation control operation of a ventilation fan concerning other embodiments of the present invention. It is an external appearance perspective explanatory view showing other embodiment of the present invention. It is the typical side surface enlarged view showing the turbulent flow state of the cooling wind in other embodiment represented by FIG. FIG. 9 is a longitudinal sectional explanatory view showing an internal schematic structure of a cooling unit according to a second embodiment of the present invention, and showing an air passage for cooling a recording medium conveying roller also serving as a heat radiating roller with cooling air. is there. It is an external appearance perspective explanatory drawing showing the cooling means concerning the embodiment shown in FIG. FIG. 10 is an external view explanatory diagram of a cooling unit according to a third embodiment of the present invention, in which two discharge ports are arranged and two cooling air exhaust ports are also arranged. In the embodiment shown in FIG. 15, the recording medium path switching flapper after the fixing device is switched to the first paper discharge side to pass the recording medium, and the air path switching guide is fed from the first exhaust opening. It is the typical side surface enlarged view which showed the state switched to. In the embodiment shown in FIG. 15, the recording medium path switching flapper after the fixing device is switched to the second paper discharge side to pass the recording medium, and the air path switching guide is fed from the second exhaust opening. It is the typical side surface enlarged view which showed the state switched to. FIG. 18 is an external perspective view illustrating the interlock mechanism of the paper discharge path switching flapper and the air path switching guide of FIGS. 16 and 17 using a link cam. It is a longitudinal cross-sectional explanatory drawing showing the internal schematic structure of the conventional fixing means (fixing apparatus) and the cooling means.

  Prior to the description of embodiments of the present invention, a schematic configuration of a copying machine using a transfer type electrophotographic process will be described with reference to FIG. 1 as an example of an image forming apparatus to which the present invention is applied.

(A) General Schematic Description of Copier Reference numeral 1 denotes a copying machine main body (recording unit), reference numeral 2 denotes an image reading unit (original scanner) disposed on the upper portion of the copying machine main body 1, and reference numeral 3 denotes A document conveying unit (ADF device) disposed on the image reading unit 2 is shown. Reference numerals 4 and 5 denote first and second paper feeds disposed in a two-tiered manner on the lower side of the copying machine main body 1. The cassette part is shown. The image reading unit 2 photoelectrically reads image information of a document. Reference numeral 31 denotes a fixed platen glass disposed on the upper surface of the image reading unit 2, and reference numeral 32 denotes a photoelectric reading unit (scanning unit) in the image reading unit 2. Each unit). The photoelectric reading unit 32 stands by in the image reading unit 2 with the position indicated by the solid line on the upper left side in FIG. Based on the reading start signal, the photoelectric reading unit 32 is moved forward at a predetermined speed from the home position to the right along the lower surface of the document table glass 31 at the predetermined position. When it reaches, it reverses and moves back to the first home position.

The document transport unit 3 can be freely opened and closed with respect to the upper surface of the document table glass 31 of the image reading unit 2.
A document pressing mechanism for the document transport mechanism and the document table glass 31 is provided. In the document scanning mode, the document transport unit 3 is closed on the document table glass 31, the document is placed on the document tray 33 with the image surface facing upward, and a print key on an operation unit (not shown) is pressed. Then, the original on the original tray 33 is separated and fed, and is discharged by the original conveying mechanism 35 onto the original discharge tray 34 via the original flow reading position 36 with the image surface facing downward. The document flow reading position 36 corresponds to the home position of the photoelectric reading unit 32 in the image reading unit 2, and the document image is positioned at the home position in the process of moving the document through the document flow reading position 36. Is read by a photoelectric reading unit 32.

  In the original document reading mode, the document conveying unit 3 is opened from the upper surface of the document table glass 31 of the image reading unit 2, and the document is placed on the upper surface of the document table glass 31 with its image surface facing downward according to a predetermined placement standard. The original is placed and the original conveying unit 3 is closed on the original, and the original is pressed down by the original pressing plate part. Next, when the print key is pressed, the photoelectric reading unit 32 of the image reading unit 2 in the image reading unit 2 has a predetermined rightward position along the lower surface of the platen glass 31 from the position of the home position indicated by the solid line on the upper left side in FIG. When it moves forward at a speed and reaches a predetermined forward movement end point, it reverses and moves backward to the first home position. In the forward movement process of the photoelectric reading unit 32, the downward image surface of the document placed on the document table glass 31 is read by the photoelectric reading unit 32.

  The document image information is read in units of pixels by the photoelectric reading unit 32, and a digitally converted signal is stored in a memory and input to a laser scanner control circuit on the copier body 1 side.

  In the copying machine main body (printer main body) 1, reference numeral 11 denotes an electrophotographic photosensitive drum, which starts to rotate when a print key is pressed. The photosensitive drum 11 is uniformly charged to a predetermined polarity and potential by the charging roller 12 during the rotation process. Next, an electrostatic latent image of the image information is formed by receiving laser beam scanning exposure of the image information by the laser scanner 13 on the uniformly charged surface. The laser scanner 13 includes a laser beam oscillator, a polygon mirror, a folding mirror, and the like, receives a photoelectric conversion digital conversion signal (time-series electric digital pixel signal) of document image information from the image reading unit 2, and receives a laser beam. A laser beam modulated in accordance with the input signal is emitted from an oscillator, and the photosensitive drum 11 surface is scanned and exposed with the laser beam by a polygon mirror and a folding mirror. The electrostatic latent image formed on the surface of the photosensitive drum 11 is developed as a toner image by the developing device 14.

  On the other hand, a sheet material 10 as a recording medium is separated and fed from the selected first or second paper feed cassette unit 4, 5 and fed into the printer main body 1, and is predetermined by a registration roller pair 7. Are introduced into a transfer portion which is a contact nip portion between the photosensitive drum 11 and the transfer roller 15. The predetermined control timing is the timing at which the leading edge of the sheet material 10 reaches the transfer portion when the leading edge of the toner image on the surface of the photosensitive drum 11 reaches the transfer portion. Then, the toner image on the surface side of the photosensitive drum 11 is sequentially transferred onto the surface of the sheet material 10 in the transfer unit.

  Reference numeral 6 indicates an MP (multi-paper) paper feeding unit. The MP paper feeding unit 6 is closed and stored in the printer main body 1 as shown by a solid line when not in use, and when in use. The sheet material 10 can be fed from the MP sheet feeding unit 6 to the printer main body 1 by placing and setting the sheet material 10 in a state where the sheet material 10 is folded and opened as shown by a two-dot chain line. . The sheet material 10 that has passed through the transfer portion is separated from the surface of the photosensitive drum 11 and is introduced into a fixing device (thermal fixing device, fixing portion, fixing unit) 8 provided as a fixing unit, so that the toner image is thermally fixed. Receive. The fixing device (fixing means) 8 of this example is a film heating type comprising a ceramic heater and a heat fixing film 8a as heat fixing means and a pressure roller 8b as pressure means.

  Further, the surface of the photosensitive drum 11 after the sheet material 10 is separated is cleaned by removing the transfer residual toner by a cleaning device (cleaning blade) 16 and repeatedly used for image formation. After fixing the toner image discharged from the fixing device (fixing means) 8, the sheet material 10 passes through a paper discharge conveyance path having a reversing path, and is imaged from a paper discharge port 86 c to a paper discharge tray (in-body paper discharge type) 18. Paper is discharged face down. The paper discharge roller 21 provided in the vicinity of the paper discharge port 86c with respect to the paper discharge tray 18 is composed of three rollers, one on the outer side of the reverse path and two on the inner side, and the two inner rollers are on the outer side. Each roller is energized. The sheet material 10 is subjected to reverse curl correction along the outer periphery of the outer roller. When a large amount of sheet material 10 is stacked on the discharge tray 18 and detected by the first full load detection sensor, the full load is displayed on the operation unit and the recording operation is stopped.

Here, in the printer main body 1, the photosensitive drum 11, the charging roller 12, the developing device 14,
The cleaning device 16 is configured as a process cartridge (see symbol PCRG in FIG. 11) that is disposed in a cartridge housing and can be attached to and detached from the printer main body 1 at once. The process cartridge is detachable at a predetermined position in the printer main body 1.

(B) Cooling device Fixing for cooling the fixing device 8 is provided at a substantially central portion in the printer main body 1 adjacent to the fixing device (fixing means) 8 as shown in FIGS. A blower fan 81 is disposed as a cooling means. The blower fans 81 are arranged one by one so as to face both ends in the longitudinal direction of the heat fixing film 8a of the fixing device 8 described above. Guide means is provided to extend to the fixing device 8. The air duct 82 in this embodiment has a substantially rectangular cross section, and is narrowed so that the cross-sectional area continuously decreases from the air blowing side of the air blowing fan 81 toward the fixing device 8. ing.

  An opening / closing shutter 83 for opening and closing the blowing duct 82 is provided in the blowing duct 82 as the blowing guide means. As shown in FIG. 4, the opening / closing shutter 83 and its driving mechanism have the same structure as in the prior art, and correspond to the size (paper width dimension) of the recording medium immediately before the heat fixing film 8a. Thus, the recording medium is moved in a direction orthogonal to the conveyance direction of the recording medium. More specifically, when a small-sized recording medium smaller than the reference sheet passing area set in the fixing device (fixing means) 8 is passed, the open / close shutter 83 is opened in accordance with the paper width size of the recording medium. Then, the cooling air sent out through the opening portion of the opening / closing shutter 83 is sent from the both end edges of the recording medium to the non-sheet passing area on the outer side so that both end portions in the longitudinal direction of the fixing device 8 are cooled. It has become.

  Here, the above-described air duct 82 is provided with a branch air duct 84 that branches from the upstream side of the opening / closing shutter 83. The branch air duct 84 has a branch opening on the upper wall surface of the air duct 82 and extends obliquely upward from the branch opening to open to the paper discharge area 85 of the printer main body 1. Is arranged. The branch air duct 84 extends from the paper discharge area 85 to the position above the paper discharge unit (paper discharge tray) 18 and above the stack surface of the recording media stacked on the paper discharge tray 18. An exhaust opening 84a is provided, and the exhaust opening 84a is provided at a position below the paper discharge roller provided in the paper discharge port 86c described above.

  As described above, the branch air duct 84 extending from the branch opening with the air duct 82 to the exhaust opening 84a through the paper discharge area 85 blows substantially parallel to the discharge direction of the sheet material 10 as the recording medium. The amount of cooling air corresponding to the amount by which the above-described opening / closing shutter 83 is closed, that is, the amount of cooling air passing through the opening portion of the air duct 82 is reduced. The recording medium that is sent to the paper discharge area 85 on the paper discharge tray 18 through 84 and discharged from the paper discharge port 86C is cooled. Thus, in this embodiment, the conventional paper discharge fan (see reference numeral 104 in FIG. 19) is omitted, and a configuration in which the function is shared by the blower fan 81 is employed.

  At this time, each unit that performs the above-described image forming operation is controlled by, for example, an image forming control unit (controller) as shown in FIG. The image formation control means in the present embodiment generally includes a ROM 301 storing various control programs necessary for the image forming operation, a volatile memory 302 and a nonvolatile memory 303 storing various data relating to the image forming operation, and various controls. A CPU (Central Processing Unit) 304 that controls the overall operation of the image forming apparatus by executing a program is provided. The CPU 304 is bus-connected to various actuators 306 involved in the image forming operation via a predetermined interface (I / O) 305. The image forming conditions such as sheet size designation, number of copies to be printed, single-sided / double-sided printing designation, enlarged / reduced printing designation, etc. are set from the control panel, while image data read by the scan unit 32 or external The image data transferred from the network is accumulated in the data storage unit, the image data is transferred from the data storage unit to the buffer memory, and the data signal is sequentially transferred from the buffer memory to the laser emitter to perform a predetermined image forming operation. Is configured to be executed.

  The above-described fixing device (fixing means) 8 and the blower fan 81 and the opening / closing shutter 83 constituting the fixing cooling means are also configured to perform predetermined operations necessary for image formation by the image formation control means. Then, the image forming control unit according to the present embodiment operates the open / close shutter 83 and the blower fan 81 based on the size of the recording medium and the temperature detection signal of the paper discharge area 85, thereby When the recording medium having the same size as the reference paper passing area of the fixing device (fixing means) 8 is passed, the shutter is opened and closed as shown in FIG. 83 is maintained in a closed state, and the discharge cooling is performed almost in the same manner as the fixing cooling, thereby preventing the performance from being deteriorated. At this time, the temperature of the paper discharge area 85 described above is detected by a non-contact temperature detection sensor 85a attached to the upper surface of the paper discharge area 85.

  At this time, as shown in FIGS. 6 and 7, the air duct 82 in the present embodiment has an extension angle of the rectifying plate 82a provided in the air duct 82 as compared with the comparative example shown in FIG. On the other hand, it is formed so as to be inclined by about 40 ° toward the center side in the paper width direction perpendicular to the discharge direction of the recording medium. As a result, even with the blower fan 81 provided in the vicinity of the end in order to cool the end portion in the fixing longitudinal direction, an almost uniform air volume can be obtained over the entire sheet including the center of the sheet.

  Next, operations of the blower fan 81 and the opening / closing shutter 83 will be described. As shown in FIG. 9, when the recording medium is started to pass through the fixing device (fixing means) 8 to form an image (step 1), the size of the recording medium used at that time (step 1). (Paper width dimension) is detected, and it is recognized whether the size of the recording medium is the same as or smaller than the width of the reference sheet passing area, that is, the fixing longitudinal width size (step 2).

  If the size of the recording medium (paper width dimension) is the same as the fixing longitudinal width size (NO in step 2), the detected temperature relating to the paper discharge area 85 of the fixing device (fixing means) 8 is read. For example, when the detected temperature is less than 73 ° C. (NO in step 3), since the discharged recording media do not adhere to each other and need not be cooled, the opening / closing shutter 83 remains open. In this state, the blower fan 81 is maintained in the drive stop state (step 4), and is executed until the end of the designated job (step 5). On the other hand, when the detected temperature of the paper discharge area 85 is 73 ° C. or higher, which is the temperature at which the surface of the discharged recording medium adheres to the paper (YES in step 3), the open / close shutter 83 is closed. (Step 6) The driving of the blower fan 81 is started (Step 7), whereby the paper discharge area 85 is cooled and executed until the end of the designated job (Step 8).

  On the other hand, if the size of the recording medium is smaller than the fixing longitudinal width size (YES in step 2), the temperature difference between the longitudinal end portions and the central portion of the fixing device (fixing means) 8 is read and determined. If there is no temperature difference between the two (NO in step 9) and the detected temperature is, for example, less than 73 ° C. (NO in step 10), the discharged recording media are connected to each other. Therefore, the blower fan 81 is maintained in the drive stop state with the open / close shutter 83 being opened (step 11) and executed until the end of the designated job. (Step 12). If there is no temperature difference between the two (NO in step 9) and the detected temperature is, for example, 73 ° C. or higher (YES in step 10), the opening / closing shutter 83 is opened because cooling is required. In the closed state (step 13), the driving of the blower fan 81 is started (step 14), and the entire fixing device (fixing means) 8 is cooled and executed until the end of the specified job ( Step 15). On the other hand, if there is a temperature difference between the longitudinal end portions and the central portion (YES in step 9), the opening / closing shutter 83 is moved in accordance with the size of the recording medium to be used (paper width size). (Step 16), the driving of the blower fan 81 is started (Step 14), and both ends in the longitudinal direction of the fixing device (fixing means) 8 are cooled. At this time, the paper discharge area 85 is also cooled from the branch air duct 84.

  As described above, when cooling both ends in the longitudinal direction of the fixing device (fixing means) 8, one of the two blower fans 81 arranged at both ends is set to the normal rotation state, and the other is set to the reverse state. Then, as shown in FIG. 10, an air flow is generated in the longitudinal direction of the fixing device 8 to enable rapid cooling.

  Further, as shown in FIG. 11, when the process cartridge PCRG is disposed below the fixing device (fixing means) 8, a large number of processes cartridge PCRG located below the opening / closing shutter 83 are arranged on the upper surface. If the protrusion PCa is provided, a turbulent flow can be generated on the upper surface of the process cartridge PCRG as shown in FIG. 12, and the cooling action is improved.

  As described above, according to the present embodiment, the cooling of the fixing device (fixing means) 8 and the cooling of the recording medium after the fixing are performed by the common blower fan 81 with a simple configuration, and both of them are cooled. The opening / closing shutter 83 is operated efficiently.

  At this time, as described above, the blower fan 81 is driven when the paper width dimension of the recording medium to be passed is shorter than the width in the longitudinal direction of the fixing device (fixing means) 8. Limited to when one or both of the conditions are met when a temperature difference occurs or when the surface temperature of the ejected recording medium exceeds the temperature at which the ejected paper is bonded. 81 does not operate. That is, in the present embodiment, the operation of the blower fan 81 is limited by detecting the temperature of each place, and energy saving is possible.

  Further, in the present embodiment, the sheet material (recording medium) 10 that is sent out from the paper discharge port 86 c of the paper discharge conveyance path and is to be stacked on the paper discharge unit (paper discharge tray) 18 is supplied to the branch air duct 84. The cooling is performed by blowing air from the exhaust opening 84a. Particularly, the front and back surfaces of the sheet material (recording medium) 10 are cooled, so that a good cooling action can be obtained.

  On the other hand, in the second embodiment according to FIGS. 13 and 14 in which the same reference numerals are given to the same constituent members as those in the first embodiment described above, the fixing device (fixing means) 8 is a sheet material (recording medium). ) A discharge roller pair 86a and a pair of intermediate transfer rollers 86b are provided in the discharge conveyance path 86 from when 10 is removed until it passes through the discharge area 85 and is discharged to the discharge section (discharge tray). A conveying roller is provided. One roller of the pair of transport rollers 86a and 86b is provided as a heat radiating roller made of aluminum or the like that takes the heat of the recording medium 10, and the transport rollers 86a and 86b as the heat radiating rollers are described above. It arrange | positions so that the ventilation which passes through the branch ventilation duct 84 may hit. With such an arrangement relationship, heat storage on the conveyance roller 86a or 86b is suppressed, and the temperature of the sheet material (recording medium) 10 that is nipped and conveyed continuously without becoming high temperature can be reduced. ing.

  According to the embodiment having such a configuration, cooling of the transport rollers 86a and 86b provided in the paper discharge transport path 86 is performed by blowing air from the branch air duct 84, so that the sheet material 10 as a recording medium can be cooled. Cooling is performed more efficiently.

  Further, in the third embodiment shown in FIGS. 15, 16, and 17, the paper discharge transport path 86 is provided so as to extend into a plurality of branches, and the plurality of paper discharge transport paths are provided. A plurality of (two) paper discharge ports 86c and 86d are provided corresponding to each of the 86, and a first paper discharge unit (paper discharge tray) 18 is provided below the paper discharge ports 86c and 86d. , And the second paper discharge unit (paper discharge tray) 19 are arranged so as to extend in an inclined manner. Then, a flapper 87 provided at a branch position of the plurality of paper discharge conveyance paths 86 is rotated by a solenoid or the like (not shown) to select a paper discharge path for the sheet material (recording medium) 10 to be conveyed. Thus, the sheet material 10 discharged from either the paper discharge port 86c or 86d is stacked on either the first paper discharge unit (discharge tray) 18 or the second paper discharge unit (discharge tray) 19. The structure is made.

  On the other hand, the branch air duct 84 is also provided so as to extend along the plurality of paper discharge conveyance paths 86 described above, and an exhaust opening of the branch air duct 84, that is, the first exhaust opening 84 a and the second exhaust air duct 84. Exhaust openings 84b are provided at positions below the discharge rollers provided at the plurality of discharge ports 86c and 86d, respectively. Each of the first and second exhaust openings 84a and 84b has recording media stacked on first and second paper discharge units (discharge trays) 18 and 19 provided in the paper discharge region 85. Are arranged so as to open at positions above the respective loading surfaces.

  Further, the branch air duct 84 is selected to select an exhaust opening from which air is blown, that is, the air from the branch air duct 84 is blown from either the first exhaust opening 84a or the second exhaust opening 84b. An air path switching guide 88 for switching the path is provided. The air path switching guide 88 is configured to perform a switching operation in conjunction with the rotation operation of the flapper 87 described above, and the paper discharge port 86c of the paper discharge path selected by the rotation of the flapper 87. Or it is comprised so that ventilation may be performed from either the 1st exhaust opening 84a or the 2nd exhaust opening 84b corresponding to 86d.

  As an interlocking mechanism between the flapper 87 and the air path switching guide 88 at this time, for example, a configuration using a link cam 89 as shown in FIG. In this example, an air path switching guide 88 is connected to a flapper 87 via an elongated plate-like link cam 89. It should be noted that such an interlocking mechanism between the flapper 87 and the air path switching guide 88 can naturally employ an interlocking mechanism that is electrically operated.

  As shown in FIG. 16, when the sheet discharge path switching flapper 87 is switched so that the sheet material (recording medium) 10 is conveyed to the sheet discharge port 86c, The path of the branch air duct 84 is also switched by the air path switching guide 88 according to the first exhaust opening 84a side at the same time. On the other hand, as shown in FIG. 17, when the sheet discharge path switching flapper 87 is switched so that the sheet material (recording medium) 10 is conveyed to the sheet discharge outlet 86d, The path of the branch air duct 84 is also switched by the air path switching guide 88 according to the second exhaust opening 84b side at the same time. As a result, it is possible to cool the sheet material 10 by selecting and blowing the used paper discharge port regardless of whether the plurality of paper discharge ports 86c and 86d are provided.

  In other words, according to the present embodiment having such a configuration, when the sheet material (recording medium) 10 is selectively transported through a plurality of paper discharge transport paths, the paper is actually transported. Only in the conveyance path, air is blown from one of the exhaust openings 84a and 84b of the branch air duct 84 with a simple configuration, and the cooling of the sheet material (recording medium) 10 is more efficient and efficient. To be done.

  Further, in the present embodiment, the first paper discharge unit (paper discharge tray) 18 or the second paper discharge unit (sent from the paper discharge roller 86a provided in the paper discharge transport path 86 and disposed in the paper discharge region ( The sheet material (recording medium) 10 that is to be stacked on the (discharge tray) 19 is cooled by blowing air from either the first exhaust opening 84 a or the second exhaust opening 84 b of the branch air duct 84. In particular, when both the front and back surfaces of the sheet material (recording medium) 10 are cooled, a good cooling action can be obtained.

  As mentioned above, although the embodiment of the invention made by the present inventor has been specifically described, it is needless to say that the present invention is not limited to the above embodiment and can be variously modified without departing from the gist thereof. Yes.

  For example, in the above-described embodiment, the present invention is applied to a copying machine, but the present invention is similarly applied to other image forming apparatuses such as a printer / facsimile and various other apparatuses. Is something that can be done.

  As described above, the image forming apparatus according to the present invention can be widely applied to various types of image forming apparatuses such as printers and copiers, and other various apparatuses.

DESCRIPTION OF SYMBOLS 1 Printer apparatus body 2 Image reading part 3 Document conveying part 4,5 Cassette paper feeding part 6 MP (multi paper)
8 Fixing device (fixing means)
8a Thermal fixing film 8b Pressure roller 10 Sheet material (recording medium)
18 First paper discharge unit 19 Second paper discharge unit 81 Blower fan (fixing and cooling means)
82 Blower duct (Blower guide means)
82a Rectifying plate 83 Opening / closing shutter 84 Branch air duct 84a First exhaust opening 84b Second exhaust opening 85 Discharge area 85a Temperature detection sensor 86 Discharge transport path 86a Discharge roller (heat radiating roller)
86b Intermediate transport roller (heat dissipation roller)
86c Discharge port 87 Discharge path switching flapper 88 Air path switching guide 89 Link cam

Claims (7)

A fixing unit for fixing a toner image on a recording medium, a fixing cooling unit for cooling the fixing unit, and an image formation control unit for causing the fixing unit and the fixing cooling unit to perform an operation relating to image formation. Because
The fixing cooling means includes an air blowing fan, an air blowing guide means having a air duct extending from the air blowing fan to the fixing means, and an open / close shutter that opens and closes the air duct of the air blowing guide means. In
The air duct is provided with a branch air duct that extends toward the paper discharge area of the fixing means,
The image forming apparatus, wherein the image forming control unit is configured to operate the opening / closing shutter and the blower fan based on a size of the recording medium and a temperature of the paper discharge area. The blower fans are respectively disposed at both ends in the paper width direction orthogonal to the discharge direction of the recording medium,
The image forming apparatus according to claim 1, wherein the branch air duct is formed so as to be inclined toward a center side in a paper width direction orthogonal to a discharge direction of the recording medium.   The image forming control unit is configured to close the open / close shutter and operate the blower fan when the size of the recording medium and the temperature of the paper discharge area are larger than a reference value. Image forming apparatus. Fixing means for fixing a toner image on a recording medium, paper discharge transport means for discharging the recording medium to a paper discharge area through a paper discharge transport path, fixing cooling means for cooling the fixing means, and these fixing means and fixing Image forming control means for causing the cooling means to perform an operation relating to image formation,
The fixing cooling means includes an air blowing fan, an air blowing guide means having a air duct extending from the air blowing fan to the fixing means, and an open / close shutter that opens and closes the air duct of the air blowing guide means. In
The air duct is provided with a branch air duct that extends from the fixing unit toward the paper discharge area downstream in the recording medium conveyance direction and has an exhaust opening that blows air to the paper discharge area.
The exhaust opening of the branch air duct is provided so as to blow air substantially in parallel with the discharge direction of the recording medium, and is formed to be inclined toward the center side in the paper width direction of the recording medium. And
The image forming apparatus, wherein the image forming control unit is configured to operate the opening / closing shutter and the blower fan based on a size of the recording medium. Paper discharge provided in the paper discharge transport path so that the exhaust opening of the branch air duct is above the loading surface of the recording medium stacked in the paper discharge area and discharges the recording medium. The image forming apparatus according to claim 4, wherein the image forming apparatus is disposed below the roller. At least one transport roller for transporting the recording medium is disposed in the paper discharge transport path,
The image forming apparatus according to claim 4, wherein the branch air duct is disposed so as to cool the transport roller by blowing air to the transport roller. The discharge conveyance path is provided so as to extend in a plurality of branches, and a plurality of discharge openings are provided corresponding to each of the plurality of discharge conveyance paths.
While configured to select and switch the discharge path of the recording medium to be conveyed by rotating a flapper disposed at a branch position of the plurality of discharge paths,
The branch air ducts are provided so as to extend along the plurality of paper discharge conveyance paths, and exhaust openings of the branch air ducts are provided at positions below the plurality of paper discharge ports, respectively. ,
The branch air duct is provided with an air path switching guide for switching the air path of the branch air duct so as to select an exhaust opening through which air is blown.
The air path switching guide performs a switching operation in conjunction with the rotation operation of the flapper, and blows air from the exhaust opening corresponding to the discharge port of the discharge path selected by the rotation of the flapper. 5. The image forming apparatus according to claim 4, wherein the image forming apparatus is configured as described above.

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