JP5012863B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus having a plurality of process units provided for each color used for forming a color image and capable of forming a color image on a recording medium.

  Conventionally, an image forming apparatus having a plurality of process units forms an electrostatic latent image on the surface of a photosensitive drum charged by a charger, and attaches toner to the surface of the photosensitive drum on which the electrostatic latent image is formed. The toner adhering to the surface of the photosensitive drum is sequentially transferred to the recording medium (that is, for each color constituting the color image). Thereafter, the image forming apparatus forms a color image on the recording medium by melting and thermally fixing the toner transferred to the recording medium with a fixing roller or the like.

  Here, the heat generated when the toner is thermally fixed to the recording medium raises the temperature inside the housing of the image forming apparatus. When the temperature inside the housing becomes high, color misregistration or the like occurs due to thermal expansion or the like of various components, leading to a reduction in image quality of the formed color image. Therefore, it is necessary to efficiently cool the inside of the apparatus housing.

  As an invention relating to this point, for example, an invention described in Patent Document 1 is known. In the image forming apparatus described in Patent Document 1, optical scanning units formed for each color constituting a color image are accommodated in a housing in a state of being arranged at a predetermined interval. In the image forming apparatus, the air introduced from the air hole formed on the surface facing the fan mounting surface is passed between the optical scanning units by the fan disposed on one side surface of the housing. Exhaust to the outside of the device. Accordingly, the image forming apparatus can cause various air flow in the housing and cool various components while ventilating the air inside the housing.

JP 2000-235287 A

  However, referring to FIG. 3 and FIG. 4 of Patent Document 1, the image forming apparatus described in Patent Document 1 has the optical scanning units arranged and accommodated in a space formed in a rectangular parallelepiped shape. The air introduced from the holes freely flows through the entire space formed in a rectangular parallelepiped shape. In other words, in the image forming apparatus, the flow rate of air between the optical scanning units may be insufficient, and cooling of each component may be insufficient.

  Further, the charging wire constituting the charger is soiled by dust or the like floating in the air inside the housing, and affects the electrostatic latent image formed on the surface of the photosensitive drum. When the flow rate between the units is insufficient, it is impossible to prevent the adhesion of dust or the like in the vicinity of the charging wire, and it is impossible to prevent the charging wire from becoming dirty and the image quality from being deteriorated.

  The present invention relates to an image forming apparatus having a plurality of process units provided for each color used for forming a color image and capable of forming a color image on a recording medium. A device is provided.

The image forming apparatus according to claim 1 of the present invention is formed between the process units when the cover is moved to the closed position and the first arm is positioned at the storage position, and is sealed in the arrangement direction of the process units. The first opening of the first arm is positioned at a position corresponding to the flowed-down space. A fan is disposed at one end of the first arm. Therefore, the image forming apparatus can exhaust the air taken in from the outside of the apparatus casing to the outside of the apparatus casing via the respective flow-down spaces and the internal space of the first opening and the first arm. . At this time, the air taken in from the outside passes through the flow-down space formed between the process units, so that the process units can be efficiently cooled. Further, since the internal space of the first arm is used as an air flow path related to exhaust, it is not necessary to provide a duct dedicated to exhaust. That is, the image forming apparatus can increase the cooling efficiency of the process unit and reduce the number of parts related to the image forming apparatus.

  The image forming apparatus according to claim 2 includes a frame having a second opening. The second opening is formed in a surface facing the arrangement direction of the process units and facing the first opening of the first arm. Therefore, the image forming apparatus can take in air outside the apparatus housing from the second opening of the frame to each flow-down space. The image forming apparatus can exhaust the air in each flow-down space to the outside of the apparatus housing through the first opening and the internal space of the first arm. Accordingly, the image forming apparatus can generate an air flow across the apparatus housing inside the apparatus housing, and can cool each process unit more efficiently.

  The image forming apparatus according to claim 3, wherein an opening area of the first opening opened at a position far from the one end to which the fan is connected has another opening closer to the one end than the first opening. It is formed larger than the opening area of one opening. Therefore, the image forming apparatus can equalize the amount of air inside the apparatus housing that is taken in from the plurality of first openings. Thereby, the image forming apparatus can cool each process unit uniformly.

  According to a fourth aspect of the present invention, in the image forming apparatus, the second arm housed in the housing position facing the first arm communicates with the communicating portion that communicates the interior of the apparatus housing with the internal space of the second arm, and each flow-down space. And a third opening that communicates with the internal space of the second arm. Therefore, when the first arm and the second arm are positioned in the respective storage positions, the image forming apparatus can perform air outside the apparatus housing via the communication portion, the internal space of the second arm, and the third opening. Can be taken into each downstream space. Then, the image forming apparatus can exhaust the air introduced into each flow-down space to the outside of the apparatus housing via the first opening and the internal space of the first arm. Since the third opening and the first opening are formed at positions facing each other via the flow-down space, the air outside the apparatus housing flows through each flow-down space more reliably. Thereby, the image forming apparatus can cool each process unit more efficiently. Further, since the internal space of the second arm is used as a flow path for introducing air into each flow-down space, there is no need to provide a dedicated duct or the like. That is, the image forming apparatus can increase the cooling efficiency of the process unit and reduce the number of parts related to the image forming apparatus.

  Further, in the image forming apparatus according to claim 5, the opening area of the third opening opened at a position far from one end of the first arm to which the fan is connected is closer to the one end than the third opening. It is formed larger than the opening area of another nearby third opening. As a result, the image forming apparatus can equalize the amount of air outside the apparatus housing that is taken into the flow-down spaces from the plurality of third openings. Thereby, the image forming apparatus can cool each process unit uniformly.

  In the image forming apparatus according to the sixth aspect, when the cover is located at the closed position, the gap between the upper surface of the process unit housed in the apparatus housing and the cover can be closed by the sealing member. As a result, the image forming apparatus can separate the flow-down spaces at the upper part of the process unit, and the air taken in from the outside of the apparatus casing can flow down through the flow-down spaces with certainty. Therefore, the image forming apparatus can intensively cool each process unit.

It is explanatory drawing which shows schematic structure of the laser printer which concerns on this embodiment. It is explanatory drawing regarding the process cartridge which comprises a laser printer. It is explanatory drawing regarding a 1st arm and a sealing member. It is explanatory drawing regarding a 2nd arm and a sealing member. It is sectional drawing which shows the structure of a fan connection part vicinity. It is explanatory drawing regarding the flowing-down space formed when an upper cover exists in a blockade position. It is explanatory drawing regarding the flow of the air in flow space.

  Hereinafter, an embodiment in which an image forming apparatus according to the present invention is embodied in a laser printer 1 will be described in detail with reference to the drawings. In the following description, a description will be given using directions based on the user when the laser printer 1 is used. That is, in FIG. 1, the right side toward the paper surface is “front side”, the left side toward the paper surface is “rear side”, the front side toward the paper surface is “left side”, and the rear side toward the paper surface is “right side”. To do. Further, the vertical direction toward the paper surface is defined as “vertical direction”.

  As shown in FIGS. 1 to 3, the laser printer 1 has a main body housing 10. The main body housing 10 is formed in a box shape having an upper opening 10 </ b> A, and includes a paper feed unit 20, an image forming unit 30, a paper discharge unit 90, and an exhaust fan 95 therein. The paper supply unit 20 supplies paper P that is a recording medium. The image forming unit 30 forms an image on the paper P fed by the paper feeding unit 20. The paper discharge unit 90 discharges the paper P on which the image is formed by the image forming unit 30 to the outside of the laser printer 1. The exhaust fan 95 is disposed on the right side surface of the main body housing 10 and exhausts air inside the main body housing 10. The paper feed unit 20, the image forming unit 30, the paper discharge unit 90, and the exhaust fan 95 will be described in detail later.

  A front cover 11 is provided on the front surface of the main body housing 10 so as to be rotatable forward and backward with a lower portion as a fulcrum. And the upper cover 12 is provided in the upper part of the main body housing | casing 10 so that rotation is possible about the hinge of the rear side of the main body housing | casing 10 (refer FIG. 3). That is, the upper cover 12 can move between an open position where the upper opening 10A is opened (see FIG. 3A) and a closed position where the upper opening 10A is closed (see FIG. 3B). Therefore, the user can perform maintenance of the image forming unit 30 by moving the upper cover 12 to the open position.

  The upper cover 12 has a paper discharge tray 13 on the upper surface thereof. The paper discharge tray 13 accumulates the paper P discharged from the main body housing 10 by the paper discharge unit 90. On the lower surface of the upper cover 12, a first arm 17, a second arm 18, an LED unit 40, and a sealing member 35 (see FIG. 3 and the like) are disposed. These points will be described in detail later with reference to the drawings.

  A main body frame 15 is provided in the main body casing 10. The main body frame 15 functions as a part of the apparatus main body that detachably accommodates each process cartridge 50 described later. The main body frame 15 includes a first side frame 15A, a second side frame 15B, and a cross member 15C, and is fixed to the main body housing 10 or the like (see FIGS. 5 and 7). The first side frame 15A constitutes the right side surface of the main body frame 15 and supports the photosensitive drum 53 directly or indirectly in cooperation with the second side frame 15B.

  The second side frame 15B constitutes the left side surface of the main body frame 15, and supports the photosensitive drum 53 directly or indirectly together with the first side frame 15A. The second side frame 15B is provided with a plurality of frame vents 19 at predetermined positions (see FIGS. 5 and 7). The frame vent 19 will be described in detail later. The cross member 15C connects the first side frame 15A and the second side frame 15B on the front side and the rear side of the main body frame 15 (see FIGS. 1 and 5).

  As shown in FIG. 1, the paper feeding unit 20 is provided in the lower part in the main body housing 10. The paper feed unit 20 is mainly composed of a paper feed tray 21 and a paper supply mechanism 22. The paper feed tray 21 stores paper P as a recording medium in a stacked state, and is detachably attached to the main body housing 10.

  The paper supply mechanism 22 is provided on the front side of the paper feed tray 21 and conveys the paper P from the paper feed tray 21 to the image forming unit 30. The paper supply mechanism 22 includes a paper feed roller 23, a separation roller 24, and a separation pad 25. The paper feed roller 23 feeds the paper P in the paper feed tray 21 from the paper feed tray 21 toward the separation roller 24. The separation roller 24 cooperates with the separation pad 25 to separate the fed paper P one by one.

  Accordingly, in the paper supply unit 20, the paper P in the paper supply tray 21 is separated one by one and sent upward. Thereafter, the sheet P is redirected backward through the transport path 28 and supplied to the image forming unit 30.

  The image forming unit 30 includes four LED units 40, four process cartridges 50, a transfer unit 70, and a fixing unit 80. Each LED unit 40 and each process cartridge 50 correspond to a color used for forming a color image. That is, each LED unit 40 and each process cartridge 50 correspond to each color of black, yellow, magenta, and cyan in order from the front of the laser printer 1.

  As shown in FIG. 2, each LED unit 40 has an LED head 41. The LED head 41 is an example of an exposure device. The LED head 41 is formed on the lower side of the LED unit 40, and is configured by arranging a plurality of light emitting units made of LEDs in the left-right direction. Each light emitting unit of the LED head 41 emits light based on a signal from a control device (not shown), and exposes the surface of the photosensitive drum 53 based on image data.

  Each LED unit 40 is attached to the lower surface of the upper cover 12 via a known link mechanism (not shown). The link mechanism is configured to be rotatable at a connection portion with the lower surface of the upper cover 12 and a connection portion with the LED unit 40. As a result, when the upper cover 12 is closed, the LED unit 40 is positioned between the predetermined process cartridges 50 and the exposure position where the LED head 41 faces the surface of the photosensitive drum 53.

  The four process cartridges 50 are arranged in the front-rear direction between the upper cover 12 and the paper feeding unit 20. The process cartridge 50 is disposed at a predetermined interval from other process cartridges 50. Each process cartridge 50 is supported by the first side frame 15A and the second side frame 15B. Each process cartridge 50 is different in only the color of toner (that is, one of black, yellow, magenta, and cyan) stored in a toner storage chamber 66 described later, and has the same configuration.

  As shown in FIG. 2, each process cartridge 50 includes a drum unit 51 and a developing unit 61. The developing unit 61 is configured to be detachable from the drum unit 51.

  The drum unit 51 includes a drum frame 52, a photosensitive drum 53, and a charger 54. The drum frame 52 constitutes a lower part of the drum unit 51 and rotatably supports the photosensitive drum 53. The drum frame 52 has an exposure hole 55 on the surface located above the photosensitive drum 53. The LED unit 40 is inserted into the exposure hole 55 when the upper cover 12 is closed.

  The photosensitive drum 53 is an example of a photosensitive member, and an electrostatic latent image is formed on the surface of the photosensitive drum 53 by the LED unit 40. The charger 54 is a so-called scorotron charger, and uniformly charges the surface of the photosensitive drum 53. The charger 54 is open at the top, and is configured so that an airflow is applied to the charging wire 54A housed inside (see FIG. 2).

  The developing unit 61 includes a developing frame 62, a developing roller 63, a supply roller 64, a layer thickness regulating blade 65, and a toner storage chamber 66. The development frame 62 rotatably supports the development roller 63 and the supply roller 64. The developing roller 63 supplies the toner supplied from the toner storage chamber 66 to the surface of the photosensitive drum 53. The supply roller 64 supplies the toner in the toner storage chamber 66 to the surface of the developing roller 63. The layer thickness regulating blade 65 regulates the thickness of the toner layer carried on the developing roller 63 to a constant thickness. The toner storage chamber 66 stores toner of any one of black, yellow, magenta, and cyan used for forming a color image.

  As shown in FIG. 1, the transfer unit 70 is disposed between the paper feeding unit 20 and each process cartridge 50. The transfer unit 70 includes a driving roller 71, a driven roller 72, a conveyance belt 73, and a transfer roller 74.

  The driving roller 71 and the driven roller 72 are arranged in parallel so as to be separated in the front-rear direction. The conveyor belt 73 is constituted by an endless belt, and is stretched between the driving roller 71 and the driven roller 72. The conveyor belt 73 is in contact with the surface of each photosensitive drum 53. In addition, four transfer rollers 74 are disposed inside the conveyor belt 73. Each transfer roller 74 is positioned below each photosensitive drum 53, and sandwiches a conveyance belt 73 with the photosensitive drum 53. A transfer bias is applied to the transfer roller 74 when the image is transferred to the paper P.

  The fixing unit 80 is disposed behind the process cartridges 50 and the transfer unit 70, and heat-fixes the image formed on the paper P by the transfer unit 70. The fixing unit 80 includes a heating roller 81 and a pressure roller 82. The heating roller 81 functions as a heat source for heat fixing of an image. The pressure roller 82 is disposed to face the heating roller 81 and presses the paper P toward the heating roller 81.

  The paper discharge unit 90 includes a paper discharge side conveyance path 91 and a conveyance roller 92. The paper discharge side conveyance path 91 is formed so as to extend upward from the exit of the fixing unit 80 and to be reversed to the front side. A plurality of conveyance rollers 92 are arranged on the paper discharge side conveyance path 91, and convey the paper P toward the paper discharge tray 13. Accordingly, the sheet P on which the toner image has been thermally fixed is conveyed on the sheet discharge side conveyance path 91 by the conveyance roller 92, is discharged to the outside of the main body housing 10, and is stored in the sheet discharge tray 13.

  Printing on the paper P in the laser printer 1 will be described. When printing on the paper P is performed, first, the surface of each photosensitive drum 53 is uniformly charged by the charger 54. Thereafter, the surface of each photosensitive drum 53 is exposed by LED light emitted from each LED unit 40. Thereby, an electrostatic latent image based on the image data is formed on each photosensitive drum 53.

  The toner in the toner storage chamber 66 is supplied to the developing roller 63 by the rotation of the supply roller 64. The toner enters between the developing roller 63 and the layer thickness regulating blade 65 by the rotation of the developing roller 63 and is carried on the developing roller 63 as a thin layer having a constant thickness.

  The toner carried on the developing roller 63 is supplied onto the photosensitive drum 53 when the developing roller 63 comes into contact with the surface of the photosensitive drum 53. As a result, the toner is selectively carried on the photosensitive drum 53 and the electrostatic latent image is visualized. That is, a toner image is formed on the photosensitive drum 53 by reversal development.

  When the paper P fed by the paper supply mechanism 22 passes between the photosensitive drum 53 and the transfer roller 74 by the driving of the conveyance belt 73, the toner image formed on each photosensitive drum 53 becomes the paper P. Transcribed above. The toner image transferred onto the paper P is thermally fixed onto the paper P as the paper P passes between the heating roller 81 and the pressure roller 82. Thereafter, the paper P on which the image is thermally fixed is conveyed by the paper discharge unit 90 and discharged onto the paper discharge tray 13.

  Next, the upper cover 12 of the laser printer 1 according to the present embodiment will be described in detail with reference to the drawings. 3 and 4, the LED units 40 attached to the lower surface of the upper cover 12 are omitted for the sake of illustration.

  As shown in FIGS. 3 to 5, a first arm 17 and a second arm 18 are disposed on the lower surface of the upper cover 12. The 1st arm 17 and the 2nd arm 18 are comprised by the square-shaped cylindrical member.

  The first arm 17 is disposed along the right opening edge of the upper opening 10A. As shown in FIG. 3, one end of the first arm 17 is pivotally supported on the rotation shaft side of the upper cover 12, and the other end is attached to the lower surface of the upper cover 12. . Therefore, the first arm 17 can rotate as the upper cover 12 rotates. As a result, when the upper cover 12 is moved to the closed position, the first arm 17 is positioned at the storage position formed on the upper part of the first side frame 15A, and the main body casing 10 is positioned along the right side surface of the main body casing 10. It is housed inside the body 10 (see FIG. 3B, FIG. 5 etc.). When the first arm 17 is stored in the storage position, the first arm 17 is positioned along the right side surface of each process cartridge 50.

  The first arm 17 includes a plurality of (three in the present embodiment) first ventilation holes 17A and a fan connection portion 17B. The first vent hole 17A is formed on the left side surface of the first arm 17 (that is, the surface facing the right side surface of each process cartridge 50), and inside the main body housing 10 and in the cylindrical first arm 17 The space (hereinafter referred to as the internal space) formed in is communicated. The fan connecting portion 17B is formed at the end of the first arm 17 on the side where the exhaust fan 95 is disposed, and the suction port of the exhaust fan 95 disposed on the right side surface of the main body housing 10 and the first arm. 17 internal spaces are connected. As shown in FIGS. 3B and 5, the fan connecting portion 17 </ b> B connects the suction port of the exhaust fan 95 and the internal space of the first arm 17 when the first arm 17 is stored in the storage position. To do. In the first arm 17, the end opposite to the fan connecting portion 17B is closed.

  As shown in FIG. 3B, each first vent 17A is formed so as to be positioned between the two process cartridges 50 when the first arm 17 is positioned at the storage position. And the opening area of each 1st vent hole 17A is formed so large that it leaves | separates from the edge part in which the fan connection part 17B was formed. That is, the opening area of the first vent 17A is the largest at the first vent 17A located between the process cartridge 50 corresponding to black and the process cartridge 50 corresponding to yellow, and the process cartridge 50 corresponding to magenta The first vent 17A located between the process cartridges 50 corresponding to cyan is the smallest. The first ventilation port 17A located between the process cartridge 50 corresponding to yellow and the process cartridge 50 corresponding to magenta has a first ventilation located between the process cartridge 50 corresponding to black and the process cartridge 50 corresponding to yellow. It is smaller than the opening 17A and larger than the first ventilation hole 17A located between the process cartridge 50 corresponding to magenta and the process cartridge 50 corresponding to cyan.

  A spring 16 is disposed on the first arm 17. The spring 16 connects a predetermined position of the first arm 17 in front of the rotation axis of the first arm 17 and the upper part of the main body housing 10 positioned behind the rotation axis of the first arm 17. Therefore, the spring 16 functions to position the upper cover 12 in the open position by applying the elastic force of the spring 16 to the first arm 17 (see FIG. 3A).

  On the other hand, the 2nd arm 18 is comprised by the square-shaped cylindrical member by which both ends were open | released, and is arrange | positioned along the left opening edge of 10 A of upper openings. As shown in FIG. 4, the second arm 18 is pivotally supported at one end on the rotating shaft side of the upper cover 12, and the other end is attached to the lower surface of the upper cover 12. . Therefore, like the first arm 17, the second arm 18 can rotate with the rotation of the upper cover 12. As a result, when the upper cover 12 is moved to the closed position, the second arm 18 is positioned at the storage position formed on the second side frame 15B and along the left side surface of the main body casing 10, the main body casing. It is housed inside the body 10 (see FIG. 5 etc.). When the second arm 18 is stored in the storage position, the second arm 18 is positioned at a position along the left side surface of each process cartridge 50.

  A spring 16 is disposed on the second arm 18. The spring 16 connects the predetermined position of the second arm 18 in front of the rotation axis of the second arm 18 and the upper part of the main body housing 10 positioned behind the rotation axis of the second arm 18. Therefore, the spring 16 functions to position the upper cover 12 in the open position by applying the elastic force of the spring 16 to the second arm 18 (see FIG. 4).

  The second arm 18 has a plurality (three in the present embodiment) of second vent holes 18A. The second vent hole 18A is formed on the right side surface of the second arm 18 (that is, the surface facing the left side surface of each process cartridge 50), and the inside of the main body housing 10 and the cylindrical second arm 18 are formed. It communicates with the interior space. In addition, since the both ends of the 2nd arm 18 are open | released, the air inside the main body housing | casing 10 can flow freely in the internal space of the 2nd arm 18. FIG.

  Each of the second vent holes 18A is formed so as to be positioned between the two process cartridges 50 when the second arm 18 is positioned at the storage position (that is, when the upper cover 12 is moved to the closed position). Has been. At this time, each second vent 18 </ b> A is opposed to the corresponding first vent 17 </ b> A via a space formed between the process cartridges 50.

  And the opening area of each 2nd vent hole 18A is formed so large that the linear distance from the fan connection part 17B leaves | separates. That is, the second vent hole 18A has the largest opening area at the second vent hole 18A located between the process cartridge 50 corresponding to black and the process cartridge 50 corresponding to yellow, and the process cartridge 50 corresponding to magenta. The second vent hole 18A located between the process cartridges 50 corresponding to cyan is the smallest. The second ventilation port 18A located between the process cartridge 50 corresponding to yellow and the process cartridge 50 corresponding to magenta is a second ventilation port located between the process cartridge 50 corresponding to black and the process cartridge 50 corresponding to yellow. It is smaller than the opening 18A and is larger than the second ventilation hole 18A located between the process cartridge 50 corresponding to magenta and the process cartridge 50 corresponding to cyan.

  As shown in FIGS. 3 and 4, a plurality of (three in this embodiment) sealing members 35 are disposed on the lower surface of the upper cover 12. The sealing member 35 is made of an elastic material such as rubber and is disposed at a predetermined position on the lower surface of the upper cover 12. The predetermined position in this case means a position facing the upper surface of the process cartridge 50 when the upper cover 12 is moved to the closed position. The sealing member 35 has a width that is the same as the width of the process cartridge 50 (dimension in the left-right direction), and has a block shape having a height that is approximately the same as the distance between the upper surface of the process cartridge 50 and the lower surface of the upper cover 12. Is formed.

  Therefore, when the upper cover 12 is moved to the closed position, the sealing member 35 comes into close contact with the upper surface of the process cartridge 50 (that is, one corresponding to yellow, magenta, or cyan), and the lower surface of the upper cover 12 and the process cartridge 50 The space formed on the upper surface is closed. Thereby, the sealing member 35 restricts the air flow in the front-rear direction of the main body casing 10 to a predetermined range formed between the process cartridges 50, and reduces the air flow in the left-right direction of the main body casing 10. Can be tolerated.

  Next, the flow-down space S formed when the upper cover 12 is moved to the closed position will be described in detail with reference to FIG. As described above, when the upper cover 12 is moved to the closed position, each sealing member 35 comes into contact with the upper surface of the corresponding process cartridge 50. In addition, below the process cartridge 50, the photosensitive drum 53 cooperates with the transfer roller 74 to sandwich the conveyance belt 73. That is, the space above the transfer unit 70 in the main body housing 10 is divided into four by the sealing member 35 and the process cartridge 50.

  In the present embodiment, by moving the upper cover 12 to the closed position, the space formed between the two adjacent process cartridges 50 by the cooperation of the sealing member 35 and the process cartridge 50 is referred to as the “flowing space S”. That's it. As shown in FIG. 6, the flow-down space S is formed at three locations between the process cartridges 50.

  As the upper cover 12 moves to the closed position, the first arm 17 and the second arm 18 move to their respective storage positions. Thereby, the first vent hole 17A and the second vent hole 18A are positioned between the adjacent process cartridges 50 (see FIG. 6). At this time, the first vent hole 17A is located at a position along the right side surface of the downflow space S, and the second vent hole 18A is located at a position along the left side surface of the downflow space S. That is, the second ventilation hole 18A is opposed to the first ventilation hole 17A via the flow-down space S.

  Next, the flow of air through the flow-down space S in the laser printer 1 according to the present embodiment will be described in detail with reference to FIGS. 6 and 7. When the upper cover 12 is moved to the closed position and the exhaust fan 95 is operated, the air outside the main body casing 10 is introduced into the main body casing 10 through the vent holes of the main body casing 10. The air introduced into the main body housing 10 is guided to the internal space of the second arm 18 from both ends of the second arm 18. And the said air is taken in into the flowing-down space S corresponding to each from each 2nd vent hole 18A with the driving | operation of the exhaust fan 95 (refer FIG. 7).

  As shown in FIG. 7, the air taken into the flow-down space S flows down to the first arm 17 according to the exhaust operation by the exhaust fan 95, and the internal space of the first arm 17 through each first vent port 17A. It is taken in. With the operation of the exhaust fan 95, the air flows down the internal space of the first arm 17 toward the fan connection portion 17 </ b> B, and is exhausted from the exhaust fan 95 to the outside of the main body housing 10.

  That is, in each flow-down space S, air introduced from the outside of the main body housing 10 crosses the flow-down space S from the left to the right of the process cartridge 50 as in the arm airflow W in FIG. The air is exhausted to the outside of the main body housing 10 by the exhaust fan 95. At this time, the air is surely exhausted to the outside of the main body housing 10 while exchanging heat with the process cartridge 50 or the like constituting the flow-down space S. Further, since the flow-down space S is divided by the sealing member 35 and the process cartridge 50, the air flow in the flow-down space S can reliably contact the process cartridge 50 and cool the process cartridge 50. As a result, the laser printer 1 can efficiently cool the process cartridge 50 and the like.

  In the present embodiment, the second side frame 15B has a plurality of frame vents 19 (see FIG. 7). The frame vent 19 is formed below the second arm 18 stored in the storage position and above the top surface of the transfer unit 70. That is, the frame vent 19 is positioned below the second vent 18A and along the left side surface of the flow-down space S.

  Therefore, the laser printer 1 can cool the process cartridge 50 by operating the exhaust fan 95 to introduce the air outside the main body housing 10 into the flow-down space S also from the frame vent 19.

  Specifically, the flow of air in the falling space S through the frame vent 19 will be described. When the exhaust fan 95 is operated, the air outside the main body casing 10 is introduced into the main body casing 10 through the vent holes of the main body casing 10. The air introduced into the main body housing 10 is taken into the corresponding flow-down spaces S from the respective frame vents 19 formed in the second side frame 15B (see FIG. 7).

  The air taken into the flow-down space S flows toward the first arm 17 in the same manner as the air flow from the second ventilation port 18A, and the internal space of the first arm 17 through each first ventilation port 17A. It is taken in. With the operation of the exhaust fan 95, the air flows down the internal space of the first arm 17 toward the fan connection portion 17 </ b> B, and is exhausted from the exhaust fan 95 to the outside of the main body housing 10.

  That is, in each flow-down space S, air introduced from the outside of the main body casing 10 crosses the flow-down space S from the left to the right of the process cartridge 50 as in the frame air flow F in FIG. The air is exhausted to the outside of the main body housing 10 by the exhaust fan 95. At this time, the air is surely exhausted to the outside of the main body housing 10 while exchanging heat with the process cartridge 50 or the like constituting the flow-down space S. Further, since the flow-down space S is divided by the sealing member 35 and the process cartridge 50, the air flow in the flow-down space S can reliably contact the process cartridge 50 and cool the process cartridge 50. As a result, the laser printer 1 can efficiently cool the process cartridge 50 and the like.

  The frame vents 19 include those located in the lower part of the flow-down space S, and the first vents 17A are located in the upper part of the flow-down space S. Further, as shown in FIGS. 1 and 2, a charger 54 is disposed below the process cartridge 50. Since the charger 54 has an opening at the top, the air flow from the frame vent 19 can flow in the vicinity of the charging wire 54 </ b> A disposed inside the charger 54. That is, the air near the charging wire 54 </ b> A can be reliably exhausted by the exhaust fan 95. Accordingly, the laser printer 1 can exhaust dust and the like floating in the vicinity of the charging wire 54 </ b> A by the exhaust fan 95. As a result, the laser printer 1 can prevent the charging wire 54A from being soiled due to dust or the like while cooling the process cartridge 50, thereby maintaining the image quality of the printed matter.

  Further, in the laser printer 1, the airflow from the second vent hole 18 </ b> A flows down the respective downflow spaces S together with the airflow from the frame vent hole 19. Thereby, since the surface of the process cartridge 50 constituting the flow-down space S can be cooled over a wide range, the laser printer 1 can cool the process cartridge 50 more efficiently.

  As described above, in the laser printer 1 according to the present embodiment, when the upper cover 12 is moved to the closed position, a plurality of flow-down spaces S are formed by the sealing members 35 and the process cartridges 50. At this time, the second vent 18A formed in the second arm 18 and the frame vent 19 formed in the second side frame 15B are positioned on one side of the flow-down space S. On the other side surface of the flow-down space S, a first ventilation port 17A formed in the first arm 17 is located. An exhaust fan 95 is connected to one end of the square cylindrical first arm 17 via a fan connecting portion 17B.

  When the exhaust fan 95 is operated, the air outside the main body housing 10 is introduced into the main body housing 10 and is taken into the flow-down space S through the inner space of the second arm 18 and the second vent hole 18A. Further, the air introduced into the main body housing 10 is taken into the flow-down space S through the frame vents 19 of the second side frame 15B. The air taken into the flow-down space S through the second vent 18A and the frame vent 19 passes through the first vent 17A of the first arm 17 and the internal space of the first arm 17 to the exhaust fan 95. From the main body housing 10 to the outside.

  Since the second ventilation hole 18A and the frame ventilation hole 19 are located at positions facing the first ventilation hole 17A via the flow-down space S, the air introduced from the outside of the main body housing 10 is allowed to flow into the flow-down space S. When flowing down while crossing the flow path, heat exchange with the process cartridge 50 constituting the outline of the flow-down space S can be performed reliably. As a result, the laser printer 1 can cool each process cartridge 50 efficiently. Further, since the internal flow paths of the first arm 17 and the second arm 18 are used as a flow path related to exhaust by the exhaust fan 95, the laser printer 1 does not need to be provided with a dedicated duct or the like, and constitutes the laser printer 1. The number of parts to be reduced can be reduced.

  The opening areas of the plurality of first vents 17 </ b> A formed in the first arm 17 are formed to be larger as they are located farther from the exhaust fan 95. In addition, the opening areas of the plurality of second ventilation holes 18 </ b> A formed in the second arm 18 are also formed larger as they are located farther from the exhaust fan 95. As a result, the laser printer 1 can flow down the flow-down space S via the second vent hole 18A and make the amount of air exhausted via the first vent port 17A uniform among the flow-down spaces S. . As a result, the laser printer 1 can uniformly cool the process cartridge 50 disposed in the main body housing 10.

  Further, the flow-down space S is separated from other flow-down spaces S adjacent by closing the lower surface of the upper cover 12 and the upper surface of the process cartridge 50 with the sealing member 35 (see FIG. 6). Accordingly, the air introduced from the outside of the main body housing 10 surely flows down in the flow-down space S toward the first vent hole 17A. As a result, the laser printer 1 can intensively cool the process cartridge 50 that forms the flow-down space S.

Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention.
For example, in the present embodiment, the air introduced into the flow-down space S from the second vent 18A and the frame vent 19 is configured to be exhausted to the outside of the main body housing 10 through the first vent 17A. However, the present invention is not limited to this mode. That is, the air outside the apparatus may be introduced into the flow-down space S from either the second vent 18 </ b> A or the frame vent 19.

  Further, in the present embodiment, the first vent hole 17A and the second vent hole 18A are formed at three locations, respectively, but the present invention is not limited to this mode. That is, the number of the first vents 17A and the second vents 18A can be freely formed according to the embodiment.

Furthermore, in the present embodiment, the three sealing members 35 are disposed on the lower surface of the upper cover 12, but this is not a limitation. As long as the upper surface of the process cartridge 50 and the upper cover 12 can be disposed, the number of the sealing members 35 may be four or two.
The image forming apparatus according to the present invention can be applied regardless of the exposure method. That is, as in the laser printer 1 according to this embodiment, an exposure method using an LED may be applied, or an exposure method using a laser beam may be applied.

DESCRIPTION OF SYMBOLS 1 Laser printer 10 Main body housing | casing 10A Upper opening 12 Upper cover 15 Main body frame 15B 2nd side frame 17 1st arm 17A 1st ventilation port 18 2nd arm 18A 2nd ventilation port 19 Frame ventilation port 35 Sealing member 50 Process cartridge 95 Exhaust fan S Down space F Frame airflow W Arm airflow

Claims (6)

An image forming apparatus capable of forming a color image on a recording medium,
A plurality of process units provided for each color used for forming the color image, and arranged in a predetermined arrangement direction at a predetermined interval;
An apparatus housing having an opening used when the plurality of process units are housed inside and when the process units housed inside are attached and detached,
The opening edge of the opening is pivotally supported so as to be movable between a closed position that closes the opening and an open position that opens the opening so that the process unit housed in the apparatus housing is detachable. Cover,
Supporting the cover, holding the cover in the open position, and when the cover is in the closed position, along the arrangement direction of a plurality of process units housed in the housing, and A first arm stored in a storage position adjacent to one end of the plurality of process units,
The first arm is
It is constituted by a hollow member having an internal space,
When the first arm is in the storage position, the flow-down is formed at a position corresponding to a flow-down space formed between the process units housed inside the apparatus housing and sealed in the arrangement direction of the process units. Each having a first opening communicating the space and the internal space;
A fan that draws air taken in from the outside of the device housing into the internal space of the first arm via the flow-down space and the first opening, and exhausts the air from the internal space to the outside of the device housing; An image forming apparatus having the first arm at one end thereof. The image forming apparatus according to claim 1,
Inside the apparatus housing, the plurality of process units are supported from the outside, face the array direction of the process units, and face the first opening of the first arm. A frame having a second opening communicating with the flow-down space;
The fan is
Air taken in from the outside of the device housing is taken into the flow-down space from the second opening, and is drawn into the internal space of the first arm via the flow-down space and the first opening. An image forming apparatus, wherein the air is exhausted from the space to the outside of the apparatus housing. The image forming apparatus according to claim 1, wherein:
In the first openings formed in the first arm,
The opening area of the first opening opened at a position far from the one end connected to the fan is formed larger than the opening area of the other first opening closer to the one end than the first opening. An image forming apparatus. An image forming apparatus according to any one of claims 1 to 3,
Supporting the cover, holding the cover in the open position, and when the cover is in the closed position, along the arrangement direction of a plurality of process units housed in the housing, and A second arm that is adjacent to the other end of the plurality of process units and is stored at a storage position facing the first arm;
The second arm is
It is constituted by a hollow member having an internal space,
When the first arm and the second arm are in the storage position, the first space and the inner space of the second arm communicate with each other at a position facing each first opening formed in the first arm. Each with three openings,
A communication portion that communicates the inside of the device housing and the internal space of the second arm at the end of the second arm;
The fan is
Air taken in from the outside of the device casing is taken into the flow-down space via the communication portion, the internal space of the second arm, and the third opening, and via the flow-down space and the first opening. The image forming apparatus is drawn into the internal space of the first arm and exhausted from the internal space to the outside of the apparatus housing. The image forming apparatus according to claim 4,
In a plurality of third openings formed in the second arm,
The opening area of the third opening that is opened at a position far from one end of the first arm to which the fan is connected is another third opening that is opened at a position closer to the one end than the third opening. An image forming apparatus, wherein the image forming apparatus is formed to be larger than an opening area of the portion. An image forming apparatus according to any one of claims 1 to 5,
The cover is
When the cover is located at the closed position, a sealing member that closes the gap between the upper surface of the process unit housed in the apparatus casing and the cover is provided on the surface facing the apparatus casing. Image forming apparatus.

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