JP2006017922A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which ensures efficient discharge of heat emitted by a heat generating source such as a heat fixing means, prevents image quality degradation caused by the occurrence of fixing failure or the like, and is miniaturized. <P>SOLUTION: The image forming apparatus forms images by using image forming means having the heat generating source. To solve the problem, the apparatus includes: an exhaust passage along which heat emitted by the heat generating source is guided to a direction perpendicular to both lengthwise ends of the heat generating source together with ambient air of the heat generating source, and then discharged outside in a direction parallel to the lengthwise direction of the heat generating body; and an air blowing means by which the heat emitted by the heat generating source is discharged outside the main body of the apparatus together with the ambient air via the exhaust passage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a printer or a copier that employs an electrophotographic system, and in particular, stably discharges heat discharged from a heat source such as a fixing device without increasing the size of the apparatus. The present invention relates to an image forming apparatus capable of discharging.

JP 2002-174972 A JP 2003-295740 A

  Conventionally, image forming apparatuses such as printers and copiers that employ this type of electrophotographic method charge the surface of a photosensitive drum as an image carrier to a predetermined potential, and then perform image exposure according to image information. An electrostatic latent image is formed, and the electrostatic latent image is visualized as a toner image. The toner image is directly transferred onto a transfer sheet and fixed by a fixing device or via an intermediate transfer member. Then, the image is transferred onto a transfer sheet and fixed by a fixing device to form an image.

  In such an image forming apparatus, heat discharged from the fixing device is discharged to the outside of the apparatus so as to prevent problems caused by adhesion of the discharged sheets and abnormal rise in temperature in the image forming apparatus main body. It is configured.

  As a technique for discharging the heat discharged from such a fixing device to the outside of the apparatus, for example, those disclosed in Japanese Patent Laid-Open Nos. 2002-174972 and 2003-295740 have already been proposed. . The electrophotographic apparatus according to JP-A-2002-174972 includes a photoreceptor having a surface on which an image is formed, an intermediate transfer member having a surface on which the image is transferred in contact with the surface, In an electrophotographic apparatus including a fixing device that fixes the image transferred in contact with the surface of an intermediate transfer member on a recording medium, a flow path provided in a longitudinal direction of the fixing device, and a downstream side of the flow path The first air blowing means provided on the upstream side and the second air exhaust means provided on the upstream side are provided, and the air flow flowing through the flow path by the first and second air blowing means is the surface of the recording medium. Is configured to flow in the same direction.

  In addition, the image forming apparatus according to Japanese Patent Application Laid-Open No. 2003-295740 includes an image forming unit that forms a toner image by transferring the toner image to a transfer target in an image forming apparatus that forms a toner image using a heating element. And a heating element that generates heat when the image forming unit forms an image, and a side surface on one side of the front and back of the apparatus body between the heating space in which the heating element is disposed and the image forming space in which the image forming unit is disposed And an air curtain forming means for forming a band-shaped air curtain in which gas flows on the other side surface facing from the side.

  However, the above prior art has the following problems. That is, in the case of the electrophotographic apparatus according to the above-mentioned Japanese Patent Application Laid-Open No. 2002-174972, a flow path provided in the longitudinal direction of the fixing device, a first air blowing means provided on the downstream side of the flow path, A second air blowing means provided on the upstream side, and an air flow from the upstream side to the downstream side of the flow path is generated, and the upstream side and the downstream side of the flow path However, there is a problem that a temperature difference occurs and fixing failure occurs due to uneven fixing heat.

  Further, in the case of the image forming apparatus according to the above-mentioned Japanese Patent Application Laid-Open No. 2003-295740, an air curtain that forms a belt-shaped air curtain in which gas flows from one side surface before and after the main body of the apparatus to the other side surface facing each other. As is the case with the above-described Japanese Patent Application Laid-Open No. 2002-174972, a temperature difference occurs between the upstream side and the downstream side of the flow path, and the blower fan used as an air curtain forming unit is provided. Has to be disposed at both ends in the width direction of the main body of the image forming apparatus, which causes a problem of increasing the size of the apparatus.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to efficiently discharge heat discharged from a heat source such as a heat fixing unit. Needless to say, it is an object of the present invention to provide an image forming apparatus capable of reducing the size of the apparatus without causing image quality deterioration due to a fixing failure.

In order to achieve the above object, an invention described in claim 1 is an image forming apparatus for forming an image using an image forming unit having a heat source.
After the heat exhausted from the heat source is guided along with the air around the heat source in a direction perpendicular to both ends in the longitudinal direction of the heat source, the heat source is outside in a direction parallel to the longitudinal direction of the heat generator. An exhaust path for discharging,
An image forming apparatus comprising: a blowing unit that exhausts heat discharged from the heat generation source through the exhaust path together with surrounding air to the outside of the apparatus main body.

  According to a second aspect of the present invention, there is provided a heat source comprising a heat fixing means for fixing the unfixed toner image transferred onto the transfer paper, and a paper discharge for storing the transfer paper fixed by the heat fixing means. 2. The image forming apparatus according to claim 1, further comprising an air blower disposed on both sides in a direction orthogonal to a paper discharge direction of the paper discharge unit.

  Further, in the invention described in claim 3, the paper discharge portion is formed by a cover member of the image forming apparatus main body, and a duct portion for communicating the heat fixing means and the air blowing means is integrally formed on the cover. The image forming apparatus according to claim 2, wherein the image forming apparatus is provided. In this way, the number of parts can be reduced, which contributes to cost reduction of the apparatus.

  According to a fourth aspect of the present invention, there is provided a paper discharge port for discharging transfer paper to the paper discharge unit between the heat fixing unit and the paper discharge unit, and an intake air for taking outside air into the heat fixing unit. The image forming apparatus according to claim 2, further comprising a mouth.

  Further, in the invention described in claim 5, the cover member is attached to the image forming apparatus main body so as to be openable and closable, and the air blowing means is located on both sides of the image forming apparatus main body. The image forming apparatus according to claim 3, wherein the image forming apparatus is disposed at a position facing each of the openings. In this way, maintenance of the image forming apparatus main body can be easily performed without increasing the size of the apparatus. Further, it is not necessary to provide an electric wire for driving the blowing means on the opening / closing member, and the apparatus is simplified.

  Further, in the invention described in claim 6, the blowing unit is disposed at a position corresponding to a central portion in the longitudinal direction of the thermal fixing unit, and blows air from the blowing unit toward the thermal fixing unit, The image forming apparatus according to claim 2, wherein the air is discharged from an outlet of the exhaust path together with air around the heat fixing unit.

  According to the present invention, the heat discharged from the heat source such as the heat fixing means can be efficiently discharged, and the image quality is not deteriorated due to the occurrence of fixing failure or the like. It is possible to provide an image forming apparatus that can be realized.

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

Embodiment 1
2 shows a tandem type full color printer as an image forming apparatus according to Embodiment 1 of the present invention, and FIG. 3 shows a tandem type full color printer as an image forming apparatus according to Embodiment 1 of the present invention. The image forming unit is shown. In addition, the arrow in FIG. 3 has shown the rotation direction of each rotation member.

  As shown in FIGS. 2 and 3, the full-color printer 01 includes photosensitive drums (image carriers) 11, 12, yellow (Y), magenta (M), cyan (C), and black (K). Image forming units 1, 2, 3, 4 having 13, 14, and charging rolls (charging means) 21, 23, 24 for primary charging that are in contact with or close to these photosensitive drums 11, 12, 13, 14 The laser optical unit shown in FIG. 2 that writes an electrostatic latent image by irradiating laser beams 31, 32, 33, and 34 of yellow (Y), magenta (M), cyan (C), and black (K). (Latent image writing means) 03, developing device (developing means) 41, 42, 43, 44, and two of the four photosensitive drums 11, 12, 13, and 14 in contact with the photosensitive drums 11 and 12 The first primary intermediate transfer drum (intermediate transfer member) 51 and the second primary intermediate transfer drum (intermediate member) contacting the other two photosensitive drums 13 and 14 (Transfer body) 52, a secondary intermediate transfer drum (intermediate transfer body) 53 in contact with the first and second primary intermediate transfer drums 51, 52, and a transfer roll (transfer) in contact with the secondary intermediate transfer drum 53 The main part is composed of the member 60). In this embodiment, in order to improve maintainability, a process including the photosensitive drums 11, 12, 13, 14 and the intermediate transfer drums 51, 52, 53, etc., excluding the developing devices 41, 42, 43, 44. The cartridge 02 is configured to be replaceable with respect to the printer main body 100.

  As shown in FIG. 3, the photosensitive drums 11, 12, 13, and 14 are arranged in parallel to each other at a constant interval so as to have a common tangential plane M.sub.2. Further, the first primary intermediate transfer drum 51 and the second primary intermediate transfer drum 52 are surfaces whose rotational axes are parallel to the photosensitive drums 11, 12, 13, and 14 and have predetermined symmetry planes as boundaries. They are arranged in a symmetrical relationship. Further, the secondary intermediate transfer drum 53 is arranged so that the rotation axis thereof is parallel to the photosensitive drums 11, 12, 13, and 14.

  Signals corresponding to the image information for each color are rasterized by an image processing unit (not shown) and input to the laser optical unit 03 shown in FIG. In the laser optical unit 03, yellow (Y), magenta (M), cyan (C), and black (K) laser beams 31, 32, 33, and 34 are modulated in accordance with image information, and the corresponding colors. The photosensitive drums 11, 12, 13, and 14 are irradiated to write an electrostatic latent image.

  Around each of the photosensitive drums 11, 12, 13, and 14, an image forming process for each color is executed by a well-known electrophotographic method. First, as the photoconductor drums 11, 12, 13, and 14, for example, photoconductor drums using an OPC photoconductor having a diameter of 20 mm are used. These photoconductor drums 11, 12, 13, and 14 are, for example, It is rotationally driven at a rotational speed of 95 mm / sec. As shown in FIG. 3, the surfaces of the photosensitive drums 11, 12, 13, and 14 are applied with a DC voltage of about -800 V to charging rolls 21, 22, 23, and 24 as contact-type charging means. For example, it is charged to about -300V. The contact type charging means includes a roll type, a film type, a brush type, etc., but any type may be used. In this embodiment, a charging roll generally used in an electrophotographic apparatus in recent years is employed. Further, in order to charge the surfaces of the photosensitive drums 11, 12, 13, and 14, in this embodiment, a charging method in which only DC is applied is used, but a charging method in which AC + DC is applied may be used.

  Thereafter, the surfaces of the photosensitive drums 11, 12, 13, and 14 correspond to yellow (Y), magenta (M), cyan (C), and black (K) colors by a laser optical unit 03 as an exposure unit. The laser beams 31, 32, 33, and 34 are irradiated, and an electrostatic latent image corresponding to input image information for each color is formed. When the electrostatic latent image is written by the laser optical unit 03, the surface potential of the image exposure portion of the photosensitive drums 11, 12, 13, and 14 is discharged to about −60 V or less.

  Further, the electrostatic latent images corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) formed on the surfaces of the photosensitive drums 11, 12, 13, and 14 are compatible. Are developed by the developing devices 41, 42, 43, and 44, and yellow (Y), magenta (M), cyan (C), and black (K) are provided on the photosensitive drums 11, 12, 13, and 14, respectively. Visualized as a toner image.

  In this embodiment, a magnetic brush contact type two-component development method is adopted as the developing devices 41, 42, 43, 44. However, the present invention is not limited to this development method. Of course, the present invention can be sufficiently applied to other development systems such as a contact development system.

The developing devices 41, 42, 43, and 44 are filled with two-component developers including yellow (Y), magenta (M), cyan (C), and black (K) toners and carriers, each having a different color. Has been. When the toner is replenished from the toner cartridges 04Y, 04M, 04C, 04K shown in FIG. 2, these replenishing toners 41, 42, 43, 44 are supplied to the auger 404 as shown in FIG. Is sufficiently agitated with the carrier and triboelectrically charged. Inside the developing roll 401, a magnet roll (not shown) having a plurality of magnetic poles arranged at a predetermined angle is fixed. By the paddle 403 that conveys the developer to the developing roll 401, the amount of the developer conveyed to the vicinity of the surface of the developing roll 401 is regulated by the developer amount regulating member 402. In this embodiment, the amount of the developer is 30 to 50 g / m ² , and the charge amount of the toner existing on the developing roll 401 at this time is about −20 to 35 μC / g.

The toner used in the developing devices 41, 42, 43, 44 has a shape factor MLS2 defined by the following equation of 100 to 140, for example, MLS2 = 130, and an average particle size of 3 μm to 10 μm. So-called “spherical toner” is used.
MLS2 = {(absolute maximum length of toner particles) × 2)}
/ {(Projection area of toner particles) × π × 1/4 × 100}

  The toner supplied onto the developing roll 401 is in the form of a magnetic brush composed of a carrier and toner by the magnetic force of the magnet roll, and this magnetic brush comes into contact with the photosensitive drums 11, 12, 13, and 14. ing. A developing bias voltage of AC + DC is applied to the developing roll 401 to develop the toner on the developing roll 401 into an electrostatic latent image formed on the photosensitive drums 11, 12, 13, and 14. It is formed. In this embodiment, the development bias voltage is about 4 kHz for AC, 1.5 kVpp, and about −230 V for DC.

  Next, the yellow (Y), magenta (M), cyan (C), and black (K) toner images formed on the photosensitive drums 11, 12, 13, and 14 are first primary images. The secondary transfer is electrostatically performed on the intermediate transfer drum 51 and the second primary intermediate transfer drum 52. The yellow (Y) and magenta (M) color toner images formed on the photoconductive drums 11 and 12 are formed on the first primary intermediate transfer drum 51 and cyan (on the photoconductive drums 13 and 14). The toner images of C) and black (K) are transferred onto the second primary intermediate transfer drum 52, respectively. Therefore, on the first primary intermediate transfer drum 51, the single color image transferred from either the photosensitive drum 11 or 12 and the two color toner images transferred from both the photosensitive drums 11 and 12 are superimposed. A double color image is formed. In addition, similar single-color images and double-color images are also formed on the second primary intermediate transfer drum 52 from the photosensitive drums 13 and 14.

  The surface potential necessary for electrostatically transferring the toner image from the photosensitive drums 11, 12, 13, 14 onto the first and second primary intermediate transfer drums 51, 52 is about +250 to 500V. It is. This surface potential is set to an optimum value depending on the charged state of the toner, the ambient temperature, and the humidity. As shown in FIG. 2, the ambient temperature and humidity are detected by an environmental sensor that detects the ambient temperature and humidity. As described above, when the charge amount of the toner is in the range of −20 to 35 μC / g and is in a normal temperature and humidity environment, the surface potential of the first and second primary intermediate transfer drums 51 and 52 is + 380V is desirable.

The first and second primary intermediate transfer drums 51 and 52 used in this embodiment have an outer diameter of 42 mm, for example, and a resistance value of about 10 ⁸ Ω. As shown in FIG. 4, each of the first and second primary intermediate transfer drums 51 and 52 is a cylindrical rotating body having a single layer or a plurality of layers whose surfaces are flexible or elastic. In addition, a low resistance elastic rubber layer 56 (R = 10 ² to 10 ³ Ω) represented by conductive silicone rubber or the like is formed on a metal pipe 55 as a metal core made of Fe, Al, or the like. It is provided at about 0.1-10mm. Further, the outermost surfaces of the first and second intermediate transfer drums 51 and 52 are typically made of a high release layer 57 (R = 10 ⁵⁾ having a thickness of 3 to 100 μm of fluororubber in which fluororesin fine particles are dispersed. ˜10 ⁹ Ω) and bonded with a silane coupling agent-based adhesive (primer) 58. What is important here is the resistance value and the releasability of the surface, and the resistance value of the high release layer is about R = 10 ⁵ to 10 ⁹ Ω. It is not limited.

  The single-color or double-color toner images formed on the first and second primary intermediate transfer drums 51 and 52 in this way are electrostatically secondary-transferred onto the secondary intermediate transfer drum 53. Accordingly, a final toner image from a single color image to a quadruple color image of yellow (Y), magenta (M), cyan (C), and black (K) is formed on the secondary intermediate transfer drum 53. Will be.

  The surface potential necessary for electrostatically transferring the toner image from the first and second primary intermediate transfer drums 51 and 52 onto the secondary intermediate transfer drum 53 is about +600 to 1200V. This surface potential is the same as when the toner is transferred from the photosensitive drums 11, 12, 13, 14 to the first primary intermediate transfer drum 51 and the second primary intermediate transfer drum 52. Will be set to the optimum value. Further, since what is necessary for the transfer is a potential difference between the first and second primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53, the first and second primary intermediate transfer drums 51 and 52 have different potentials. It is necessary to set the value according to the surface potential. As described above, the charge amount of the toner is in the range of −20 to 35 μC / g, and the surface potential of the first and second primary intermediate transfer drums 51 and 52 is +380 V in a normal temperature and humidity environment. The surface potential of the secondary intermediate transfer drum 53 is about +880 V, that is, the potential difference between the first and second primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 is + It is desirable to set it to about 500V.

The secondary intermediate transfer drum 53 used in this embodiment is formed to have the same outer diameter as that of the first and second primary intermediate transfer drums 51 and 52, for example, 42 mm, and the resistance value is set to about 10 ¹¹ Ω. . Similarly to the first and second primary intermediate transfer drums 51 and 52, the secondary intermediate transfer drum 53 is a cylindrical rotating body having a single layer or a plurality of layers whose surface is flexible or elastic. In general, a low resistance elastic rubber layer (R = 10 ² to 10 ³ Ω) typified by conductive silicone rubber or the like is formed on a metal pipe as a metal core made of Fe or Al. It is provided at about 0.1-10mm. Further, the outermost surface of the secondary intermediate transfer drum 53 is typically formed by forming a fluororubber in which fluororesin fine particles are dispersed as a high release layer having a thickness of 3 to 100 μm, and a silane coupling agent-based adhesive. (Primer). Here, the resistance value of the secondary intermediate transfer drum 53 needs to be set higher than that of the first and second primary intermediate transfer drums 51 and 52. Otherwise, the secondary intermediate transfer drum 53 will charge the first and second primary intermediate transfer drums 51, 52, making it difficult to control the surface potential of the first and second primary intermediate transfer drums 51, 52. Become. The material is not particularly limited as long as the material satisfies such conditions.

  Next, the final toner image from the single color image to the quadruple color image formed on the secondary intermediate transfer drum 53 is tertiary transferred onto the transfer paper P passing through the paper transport path by the final transfer roll 60. Is done. As shown in FIG. 2, the transfer paper P passes through a registration roller 90 from a paper feed cassette 91 through a paper feeding process, and is fed into a nip portion between the secondary intermediate transfer drum 53 and the transfer roll 60. After this final transfer step, the final toner image formed on the transfer paper P is fixed by heat and pressure by a fixing device 70 as a heat fixing means, and is a discharge tray provided on the upper part of the full-color printer main body 100. A series of image forming processes is completed. The fixing device 70 has a heating roller 71 having a heating source such as a halogen lamp inside and a pressure belt 72 pressed against each other, and heat-presses the transfer paper P onto which an unfixed toner image has been transferred, thereby unfixing. The toner image is fixed on the transfer paper P.

The final transfer roll 60 has, for example, an outer diameter of 20 mm and a resistance value of about 10 ⁸ Ω. The final transfer roll 60 is configured, for example, by providing a coating layer made of urethane rubber or the like on a metal shaft and coating it as necessary. The optimum voltage of the voltage applied to the final transfer roll 60 varies depending on the ambient temperature, humidity, paper type (resistance value, etc.), and is about +1200 to 5000V. In this embodiment, a constant current method is employed, and a current of about +10 μA is applied in a normal temperature and humidity environment to obtain a substantially appropriate transfer voltage (+1600 to 2000 V).

  Further, when images are formed on both sides of the transfer paper P, as shown in FIG. 2, the transfer paper P on which the image is formed on one side is not directly discharged onto the discharge tray T, but is turned upside down. In this state, the transfer paper P is conveyed again to the transfer section via the double-sided paper conveyance path 07, and an image is formed on the back surface of the transfer paper P.

  In FIG. 2, reference numeral 08 denotes a paper feed roll for transporting the transfer paper P supplied from a manual feed tray (not shown), 09 denotes a control circuit, and 10 denotes a power supply circuit.

  By the way, in this embodiment, in an image forming apparatus that forms an image using an image forming unit having a heat source, the heat discharged from the heat source is combined with the air around the heat source and the length of the heat source. And then exhausting the heat discharged from the heat source through the exhaust path to the surroundings. It is comprised so that the ventilation means exhausted with the air to the exterior of an apparatus main body may be provided.

  Further, in this embodiment, a heat generation source including a heat fixing unit that fixes the unfixed toner image transferred onto the transfer paper, a paper discharge unit that stores the transfer paper fixed by the heat fixing unit, It is comprised so that the ventilation means arrange | positioned at the both sides of the direction orthogonal to the paper discharge direction of a paper discharge part may be provided.

  Further, in this embodiment, the paper discharge portion is formed by a cover member of the image forming apparatus main body, and the cover is integrally provided with a duct portion for communicating the heat fixing means and the air blowing means. Has been.

  In this embodiment, a paper discharge port for discharging transfer paper to the paper discharge unit and an air intake port for taking outside air into the heat fixing unit are provided between the heat fixing unit and the paper discharge unit. It is configured as follows.

  Further, in this embodiment, the cover member is attached to the image forming apparatus main body so as to be openable and closable, and the air blowing means includes openings of the duct portion located on both sides of the image forming apparatus main body. It is comprised so that it may each be arrange | positioned in the position which opposes.

  That is, in this embodiment, as shown in FIG. 2, a transfer paper P on which an unfixed toner image is fixed by heating and pressing by a fixing device 70 as a heat fixing means is provided on the upper portion of the printer main body 100. It is configured to be discharged onto the discharged paper discharge tray T. The fixing device 70 includes a heating roll 71 having a heating source such as a halogen lamp inside, and discharges heat to the outside when performing a fixing process. Further, the fixing device 70 is disposed above the printer main body 100 and on the front side of the paper discharge tray T, and the heat generated from the fixing device 70 remains in the printer main body 100 in the state as it is. It stays in the upper part of the machine and causes the temperature inside the machine to rise unintentionally.

  Therefore, in this embodiment, as shown in FIG. 1, a duct for communicating a fixing device 70 and left and right fans 102 as air blowing means with a top cover 101 as a cover member constituting a part of the paper discharge tray T. The portions 103 and 104 are integrally provided, and the duct portions 103 and 104 guide the heat exhausted from the fixing device 70 in a direction orthogonal to both longitudinal ends of the fixing device 70 together with air around the fixing device 70. After that, the exhaust passages 105 and 106 are formed so as to discharge to the outside in a direction parallel to the longitudinal direction of the fixing device 70. In addition, the outlet portions of the exhaust passages 105 and 106 formed by the duct portions 103 and 104 serve as blowing means for exhausting the heat discharged from the fixing device 70 through the exhaust passages 105 and 106 to the outside of the printer main body 100 together with the surrounding air. The fans 102 and 102 are configured to be respectively disposed.

  The printer main body 100 is usually covered with a top cover 101, a front cover 107, and the like as shown in FIGS. Further, as shown in FIGS. 7 to 10, the top cover 101 is attached to the top of the printer main body 100 so as to be openable and closable with the front cover 107 of the printer main body 100 opened. With the open, the process cartridge 02 can be exchanged. As shown in FIGS. 11 and 12, the top cover 101 is formed in a substantially rectangular shape that is long in the width direction. In the vicinity of both ends of the top cover 101 in the width direction, the top cover 101 faces the back side. Left and right arm portions 108 and 109 are provided so as to project from the printer main body 100 so as to be freely opened and closed. In addition, a discharge tray T is formed at a central portion of the top cover 100 so as to be inclined deeper toward the front side, and an end on the front side of the discharge tray T is A plurality of louvers 112 are provided along the width direction for guiding the air introduced from the air intake port 111 formed at the lower portion of the paper discharge port 110 for discharging the paper P substantially in parallel. As shown in FIG. 13, a plurality of the air inlets 111 are opened along a direction orthogonal to the discharge direction of the transfer paper P.

  Further, at both ends of the top cover 101 in the width direction, as shown in FIGS. 11 to 13, the heat discharged from the fixing device 70 together with the air around the fixing device 70 in the longitudinal direction of the fixing device 70. Duct portions 103 and 104 are formed integrally to form an exhaust path for discharging to both outer sides in a direction parallel to the longitudinal direction of the fixing device 70 after being once guided in a direction perpendicular to both ends of the fixing device 70. As shown in FIGS. 1, 11, and 12, the air inlets 113 and 114 are opened in a rectangular shape in the duct portions 103 and 104 of the top cover 101 at positions corresponding to both ends in the longitudinal direction of the fixing device 70. Yes. Further, the exhaust passages 105 and 106 located at the rear ends of the intake ports 113 and 114 are closed, and the exhaust passages 105 and 106 are bent outward by 90 degrees in a direction parallel to the longitudinal direction of the fixing device 70. As shown in FIGS. 14 and 15, the exhaust ports 115 and 116 of the exhaust passages 105 and 106 are opened in a rectangular shape toward both side surfaces of the printer main body 100.

  Further, as shown in FIGS. 5 and 6, fans 102 as air blowing means are disposed on both side surfaces of the printer body 100 at positions communicating with the exhaust ports 115 and 116 of the duct portions 103 and 104 of the top cover 101, respectively. ing. When the fixing device 70 is energized, the heat released from the fixing device 70 is driven by the air flow A exhausted from the exhaust paths 105 and 106 by driving the fans 102. The air is sucked in from the intake ports 113 and 114 of the exhaust passages 105 and 106 opened so as to face both ends in the longitudinal direction, and is exhausted to the outside of the printer main body 100 by the fan 102 through the exhaust passages 105 and 106. Further, as shown in FIG. 1, external air A is supplied from an air inlet 111 provided in the top cover 100 in the vicinity of the fixing device 70 that becomes negative pressure due to the exhaust from the fan 102. The ambient air A supplied to the vicinity of the fixing device 70 is opposed to both ends in the longitudinal direction of the fixing device 70 as described above. Then, the air is sucked in from the intake ports 113 and 114 of the exhaust paths 105 and 106 opened as described above, and is exhausted to the outside of the printer main body 100 by the fan 102 through the exhaust paths 105 and 106.

  In the above configuration, in the full color printer according to this embodiment, the heat discharged from the heat source such as the heat fixing means can be efficiently discharged as follows, as well as the fixing failure, etc. The image quality is not deteriorated and the apparatus can be downsized.

  That is, in the full-color printer 01 according to this embodiment, as shown in FIGS. 2 and 3, the fixing device 70 is energized with the start of the printer operation, and the heating roller 71 of the fixing device 70 has a predetermined temperature. To be in a state where fixing processing is possible. Note that the heating roller 71 of the fixing unit 70 may be preheated to a predetermined preheating state even in a standby state. When the heating roller 71 of the fixing device 70 is heated to a predetermined temperature, a printing operation is started by the process cartridge 02, and unfixed toner such as full color on the transfer paper P fed from the paper feed cassette 05 After the image is finally transferred, the transfer paper P on which the unfixed toner image is fixed by being heated and pressurized by the fixing device 70 is discharged onto a paper discharge tray T provided on the upper portion of the printer main body 100. .

  At that time, in the full color printer 01, when the fixing device 70 is energized and the heating roller 71 of the fixing device 70 is heated, heat is released from the fixing device 70 to the inside of the printer main body 100, and the state is left as it is. Then, an unintentional temperature rise in the printer main body 100 is caused.

  Therefore, in this embodiment, the fans 102 disposed on both side surfaces of the printer main body 100 are driven in synchronization with the energization of the fixing device 70, and the heat released from the fixing device 70 is transferred to the fixing device 70. By discharging the air A to the outside of the printer main body 100 together with the surrounding air A, the temperature inside the printer main body 100 is prevented from unintentionally rising.

  When the fans 102 arranged on both side surfaces of the printer main body 100 are driven, the air A in the exhaust passages 105, 106 is externally introduced from the exhaust ports 115, 116 of the exhaust passages 105, 106 arranged to communicate with the exhaust fan 102. To be discharged. At that time, since the air inlets 113 and 114 of the exhaust paths 105 and 106 are opened in the vicinity of both end portions in the longitudinal direction of the fixing device 70 as shown in FIG. As shown in FIG. 17, together with the air A around the fixing device 70, the air is introduced into the exhaust passages 105 and 106 formed by the duct portions 103 and 104 from the intake ports 113 and 114, and as described above, the air is discharged from the exhaust ports 115 and 116 by the fan 102. To be discharged.

  Further, as the suction from the intake ports 113, 114 of the exhaust passages 105, 106 becomes negative pressure around the fixing device 70, as shown in FIG. 16 and FIG. Fresh fresh air A is introduced from an air inlet 111 provided at the base end portion of the paper discharge tray T, and the fixing device 70 is cooled. Then, the air is sucked from the air inlets 113 and 114 of the exhaust paths 105 and 106 and discharged to the outside. .

  Thus, in the above embodiment, the heat discharged from the fixing device 70 can be efficiently discharged, and the flow of air A to the fixing device 70 is the longitudinal direction of the fixing device 70. Therefore, the fixing device 70 is not biased toward the one end side of the fixing device 70 and is not cooled, and a fixing defect or the like is not caused to deteriorate the image quality.

  In the above embodiment, the exhaust paths 105 and 106 for discharging the heat discharged from the fixing device 70 to the outside are not disposed at both ends along the longitudinal direction of the fixing device 70, but the fixing device 70. It is arranged in a direction orthogonal to both ends in the longitudinal direction of 70, and is then formed so as to be discharged to the outside in a direction parallel to the longitudinal direction of the fixing device 70. For this reason, the exhaust passages 105 and 106 and the fan 102 do not protrude to both ends in the longitudinal direction of the fixing device 70, so that an increase in the width of the printer main body 100 can be avoided and the apparatus can be downsized. It has become.

  In the above embodiment, the exhaust passages 105 and 106 are configured to bend in a horizontal plane. However, the exhaust passages 105 and 106 are bent in a vertical plane, for example, the exhaust ports of the exhaust passages 105 and 106 are formed on the bottom surface of the printer main body 100. You may comprise so that it may provide.

Embodiment 2
FIG. 18 shows a second embodiment of the present invention. The same parts as those of the first embodiment will be described with the same reference numerals. The heat fixing unit is disposed at a position corresponding to the central portion in the longitudinal direction, blows air from the blowing unit toward the heat fixing unit, and discharges from the outlet of the exhaust path together with air around the heat fixing unit. It is configured.

  That is, in the second embodiment, as shown in FIG. 18, the fan 102 as the air blowing means is disposed at a position corresponding to the central portion in the longitudinal direction of the fixing device 70. After the air is blown toward 70 and dispersed to the left and right along the longitudinal direction of the fixing device 70, the exhaust paths 105 and 106 configured in the same manner as in the first embodiment are formed together with the air A around the fixing device 70. It is comprised so that it may be discharged outside via.

  In the case of the second embodiment, only one fan 102 as the air blowing means is required, the configuration of the apparatus can be further simplified, and the cost can be reduced.

  In the second embodiment, when a part of the airflow A discharged from the fan 102 is discharged from the intake port 111, the intake port 111 may not be provided. .

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

FIG. 1 is a perspective configuration diagram showing a main part of a tandem type full-color printer as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a tandem type full color printer as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 3 is a block diagram showing an image forming unit of a tandem type full color printer as an image forming apparatus according to Embodiment 1 of the present invention. FIG. 4 is an external plan view of a tandem type full-color printer as the image forming apparatus according to Embodiment 1 of the present invention. FIG. 5 is an external perspective view in which a part of the tandem type full-color printer as the image forming apparatus according to Embodiment 1 of the present invention is broken. FIG. 6 is an external perspective view in which a part of the tandem type full-color printer as the image forming apparatus according to Embodiment 1 of the present invention is broken. FIG. 7 is a configuration diagram showing a state in which the cover of the full-color printer is opened. FIG. 8 is a perspective view showing a state in which the cover of the full-color printer is opened. FIG. 9 is a perspective view showing a state in which the cover of the full color printer is opened. FIG. 10 is a perspective view showing a state in which the cover of the full-color printer is opened. FIG. 11 is an external perspective view showing the top cover. FIG. 12 is an external perspective view showing the top cover. FIG. 13 is a front view showing the top cover. FIG. 14 is a right side view showing the top cover. FIG. 14 is a left side view showing the top cover. FIG. 16 is a schematic diagram showing the air flow of the tandem type full color printer as the image forming apparatus according to Embodiment 1 of the present invention. FIG. 17 is a schematic diagram showing the air flow of the tandem type full-color printer as the image forming apparatus according to Embodiment 1 of the present invention. FIG. 18 is a schematic diagram showing an air flow of a tandem type full color printer as an image forming apparatus according to Embodiment 2 of the present invention.

Explanation of symbols

  70: fixing unit, 100: printer main body, 101: top cover, 102: fan, 103, 104: duct part, 105, 106: exhaust path, 113, 114: intake port, 115, 116: exhaust port.

Claims (6)

In an image forming apparatus for forming an image using an image forming unit having a heat source,
After the heat exhausted from the heat source is guided along with the air around the heat source in a direction perpendicular to both ends in the longitudinal direction of the heat source, the heat source is outside in a direction parallel to the longitudinal direction of the heat generator. An exhaust path for discharging,
An image forming apparatus comprising: a blowing unit that exhausts heat discharged from the heat generation source through the exhaust path together with surrounding air to the outside of the apparatus main body. A heat source comprising a heat fixing means for fixing the unfixed toner image transferred onto the transfer paper, a paper discharge section for storing the transfer paper fixed by the heat fixing means, and a paper discharge direction of the paper discharge section. The image forming apparatus according to claim 1, further comprising an air blowing unit disposed on both sides in the orthogonal direction. The discharge unit is formed by a cover member of an image forming apparatus main body, and a duct unit that integrally connects the heat fixing unit and the blowing unit is provided in the cover. Image forming apparatus. The discharge port for discharging transfer paper to the discharge unit and the intake port for taking outside air into the heat fixing unit are provided between the thermal fixing unit and the discharge unit. The image forming apparatus according to 2. The cover member is attached to the image forming apparatus main body so as to be openable and closable, and the blower is disposed at a position facing the opening of the duct portion located on both sides of the image forming apparatus main body. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. The air blowing means is disposed at a position corresponding to a central portion in the longitudinal direction of the heat fixing means, blows air from the air blowing means toward the heat fixing means, and the exhaust path together with air around the heat fixing means. The image forming apparatus according to claim 2, wherein the image forming apparatus is discharged from an outlet of the image forming apparatus.

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