JP2008224747A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus configured to uniformly and effectively cool the whole image forming unit with a cooling fan. <P>SOLUTION: Flexible tubes 53 to 56 are flexibly disposed so as to connect the air sending port 52a of the cooling fan 52 and a toner box 51. A plurality of openings 53a to 53e, 54a to 54e, 55a to 55e and 56a to 56e formed in the upper sides of the side faces of the flexible tubes 53 to 56 are formed so that the open area may become successively larger from the front side to the rear side of the bottom surface of the toner box 51, consequently, even when the temperature rise is varied between the front and rear sides of the bottom surface of the toner box 51, the whole bottom surface of the toner box 51 is uniformly and effectively cooled. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that prints an image on a printing medium such as printing paper, and more particularly to a configuration in which a cooled portion such as an image forming unit is cooled by a cooling fan.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a printer, a copier, a facsimile machine, and a multifunction machine having these functions has a built-in image forming unit including a photosensitive drum (image carrier) in the main body. Since the image forming unit generates heat when forming an electrostatic latent image on the surface of the photosensitive drum or developing it to form a toner image, it is necessary to cool the surface of the photosensitive drum appropriately. There is. In the tandem image forming apparatus described in Patent Document 1 below, the cooling fan outlet and the image forming unit are connected by a main duct and a branch duct, and cooling air is sent from the cooling fan to the image forming unit. The photosensitive drum surface and the like are cooled (see Patent Document 1).

  An image forming apparatus that supports tandem full-color printing includes image forming units for each color of magenta, cyan, yellow, and black, and each image forming unit for each color stores toner for each color. It has four toner boxes. In these four toner boxes (cooled parts), heat is generated by the friction of the sliding part of the stirring shaft and the blades when the toner is stirred. There is a possibility that the toner loses fluidity due to heat and cannot form an appropriate image.

For this reason, in the known image forming apparatus, the outlet of the cooling fan and each toner box are connected by four branch ducts, and the cooling air from the cooling fan is supplied to each toner box through each duct. By doing so, each toner box is uniformly cooled.
JP 2002-6697 A (FIG. 1)

  However, for example, when the rear (back) side of the image forming apparatus faces the wall surface of the room, the heat generated during the operation of the image forming apparatus is unlikely to be dissipated to the outside on the rear side. For this reason, the rear side of the image forming unit in the apparatus main body is more likely to accumulate heat than the front side, and as a result, the temperature rise is distributed between the rear side and the front side in the apparatus main body.

  In such a case, even if the cooling air is blown uniformly on the photosensitive drum surface or the longitudinal direction of the toner box using the branch duct mentioned in the prior art, the cooling efficiency is improved between the rear side and the front side. There has been a problem that variation occurs, and in particular, cooling of a portion where the temperature rise is large becomes insufficient.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of cooling uniformly and effectively in the longitudinal direction of a portion to be cooled.

  The image forming apparatus of the present invention includes a cooling fan that supplies cooling air to a cooled portion provided over a range having a predetermined length in the apparatus main body, and the cooling air is blown out from the cooling fan. The air outlet and the portion to be cooled are connected by the air flow passage, and cooling air is blown out from the air flow passage to cool the portion to be cooled. In particular, in the present invention, the air flow path is configured to extend to a position adjacent to the portion to be cooled along the longitudinal direction, and is cooled at a position facing the outer surface of the air flow path along the longitudinal direction of the portion to be cooled. The above problem is solved by providing an opening for blowing out the wind.

  According to the image forming apparatus of the present invention, for example, if the temperature rise width of the cooled portion is large on the rear side of the apparatus main body, the air flow path is extended to the rear side in the apparatus main body accordingly, and the rear side By forming the opening at the position, the cooling air can be blown in a concentrated manner at a high temperature rise. Thereby, the distribution of the temperature rise in the apparatus main body can be effectively eliminated.

  More preferably, a plurality of openings are formed on the outer surface of the air flow passage at positions facing each other along the longitudinal direction of the cooled portion. In this case, since the cooling air is blown to the cooled portion at a plurality of positions in the longitudinal direction, the cooled portion can be uniformly cooled along the longitudinal direction according to the temperature rise distribution.

  Alternatively, the plurality of openings may have modes in which cooling air blowing areas are different from each other in accordance with the distribution of the temperature rise seen in the longitudinal direction of the part to be cooled. In such an embodiment, the blowout area is increased at a location where the temperature rise is large, and the blowout area is reduced at a location where the temperature rise is small, so that the temperature rise is uniform according to the temperature rise distribution in the longitudinal direction. Cooling can be performed.

  Moreover, the aspect by which the blowing area of a cooling wind is expanded as the some opening part goes to the back side from the front side of a to-be-cooled part in the outer surface of a ventilation flow path may be sufficient. In this case, even in a situation where heat is more likely to be accumulated on the rear side than on the front side of the apparatus main body, the entire cooled portion can be uniformly cooled by increasing the cooling efficiency on the rear side.

  The air flow path is a flexible tube that connects between the air blowing port from which the cooling air is blown from the cooling fan and the part to be cooled, and has an outer surface adjacent to the longitudinal direction of the part to be cooled. There may be.

  With such a configuration, even if there is no space to provide a duct or the like in the main body of the device, the flexible tube is deformed and the gap between each component is sewn and routed, and the cooling fan and the part to be cooled are securely connected. can do.

  When the flexible tube is used, the shape of the opening for blowing the cooling air may be a shape having the same aspect ratio such as a circle or a square, or a shape having a different aspect ratio such as an ellipse or a rectangle. In particular, when the latter type is employed, the opening area can be changed to a larger or smaller size by changing the horizontal (longitudinal direction of the flexible tube) dimension. In this case, it is particularly advantageous in providing variation in the opening area when the opening is formed in the flexible tube.

  In the above-described image forming apparatus, the cooled portion may be a plurality of image forming units that form magenta, cyan, yellow, and black toner images on the image carrier. With such a configuration, in an image forming apparatus that supports full-color printing, each image forming unit can be uniformly and effectively cooled in accordance with the distribution of temperature rise in the longitudinal direction.

  According to the image forming apparatus of the present invention, it is possible to cool uniformly according to the distribution of the temperature rise in the longitudinal direction of the portion to be cooled. As a result, it is possible to eliminate variations in the thermal effect seen in the longitudinal direction of an image forming unit (developer) having an image carrier, a toner box, and the like, and to increase the fluidity of the toner to form a high quality image.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory diagram showing a configuration example of an image forming apparatus 1 which is an embodiment of an image forming apparatus according to the present invention. The image forming apparatus 1 includes a printer, a copier, a facsimile machine, and a multifunction machine having both functions of transferring a toner image onto the surface of a printing medium such as printing paper based on image information input from the outside. And a cooling fan that cools a portion of the image forming unit where heat is generated in the apparatus main body by a printing operation.

  An image forming apparatus 1 shown in FIG. 1 is a tandem color printer, for example. The image forming apparatus 1 includes a square box-shaped apparatus main body 2 that forms (prints) a color image on a sheet therein, and an upper surface portion of the apparatus main body 2 is used to discharge the sheet on which the color image is printed. A paper discharge unit (discharge tray) 3 is provided.

  In the lower part of the apparatus main body 2, a paper feed cassette 5 for storing paper is disposed. A stack tray 6 for supplying manually fed sheets is disposed at the center of the apparatus main body 2. An image forming unit 7 that forms an image on a sheet based on image data such as characters and patterns transmitted from the outside of the apparatus is provided on the upper part of the apparatus body 2. In addition, a first transport path 9 for transporting paper fed from the paper feed cassette 5 to the image forming unit 7 is disposed on the left side of the apparatus main body 2 in FIG. A second transport path 10 for transporting the sheet fed from the stack tray 6 to the image forming section 7 is disposed over the section. In the upper left part of the apparatus main body 2, a fixing unit 14 that performs a fixing process on a sheet on which an image is formed by the image forming unit 7 and a sheet that has been subjected to the fixing process are conveyed to the sheet discharging unit 3. 3 conveyance paths 11 are arranged.

  The paper feed cassette 5 can be replenished by pulling it out of the apparatus main body 2 (for example, the front side in FIG. 1). The paper feed cassette 5 includes a storage unit 16 that can selectively store at least two types of paper having different sizes in the paper supply direction. The paper is fed one by one to the first conveying path 9 by the roller 18.

  The stack tray 6 includes a tray 19 on the right side of the apparatus body 2 on which manual feed sheets are stacked, and the sheets stacked on the tray 19 are first printed one by one by a pickup roller 20 and a separating roller 21. 2 is fed to the side of the transport path 10.

  The first conveyance path 9 and the second conveyance path 10 merge before the registration roller 22, and the secondary transfer roller 23 causes a full-color toner image on an intermediate transfer belt 40 described later to be secondary to the sheet. Transcribed. Thereafter, the sheet on which the toner image is fixed by the fixing unit 14 is reversed in the fourth conveyance path 12 as necessary, and a full-color toner image is formed on the surface opposite to the first by the secondary transfer roller 23. Secondary transferred. After the toner image on the opposite surface is fixed by the fixing unit 14, the toner image passes through the third conveyance path 11 and is discharged to the paper discharge unit 3 by the discharge roller 24.

  The image forming unit 7 includes a first image forming unit 26 that forms a black (B) toner image, a second image forming unit 27 that forms a yellow (Y) toner image, and cyan (C) toner. A full-color toner image formed by the third image forming unit 28 that forms an image, a fourth image forming unit 29 that forms a magenta (M) toner image, and each of the image forming units 26 to 29 is formed on a sheet. And a transfer conveyance unit 30 for transferring.

  Each of the image forming units 26 to 29 includes a photosensitive drum 32, a charging unit 33 disposed so as to face the peripheral surface of the photosensitive drum 32, and a periphery of the photosensitive drum 32 on the downstream side of the charging unit 33. A laser scanning unit 34 for irradiating a laser beam to a specific position on the surface, and a developing unit disposed on the downstream side of the laser beam irradiation position from the laser scanning unit 34 and facing the peripheral surface of the photosensitive drum 32 35 and a cleaning unit 36 disposed on the downstream side of the developing unit 35 and facing the peripheral surface of the photosensitive drum 32.

  The photosensitive drums 32 of the image forming units 26 to 29 are rotated counterclockwise in the drawing by a drive motor (not shown). Further, in the developing units 35 of the image forming units 26 to 29, black toner, yellow toner, cyan toner, and magenta toner are stored in the toner boxes 51, respectively.

  The transfer conveyance unit 30 includes a rear roller (driving roller) 38 disposed in the vicinity of the first image forming unit 26 and a front roller (driven roller) disposed in the vicinity of the fourth image forming unit 29. ) 39, the intermediate transfer belt 40 disposed across the rear roller 38 and the front roller 39, and the intermediate transfer belt at a position downstream of the developing unit 35 in the photosensitive drum 32 of each of the image forming units 26 to 29. And four transfer rollers 41 disposed so as to be capable of being pressed through 40.

  In the transfer conveyance unit 30, the toner images of the respective colors are superimposed and transferred onto the intermediate transfer belt 40 at the position of the transfer roller 41 of each of the image forming units 26 to 29. Become.

  The first conveyance path 9 conveys the sheet fed from the paper feed cassette 5 to the transfer conveyance unit 30 side, and includes a plurality of conveyance rollers 43 disposed at predetermined positions in the apparatus main body 2. The image forming unit 7 includes a registration roller 22 that is disposed in front of the transfer / conveying unit 30 for timing the image forming operation and the paper feeding operation.

  The fixing unit 14 performs a fixing process by heating the sheet on which the toner image is transferred in the image forming unit 7. The fixing unit 14 is heated by a built-in heater, and the fixing unit 14 is heated. A pressure roller 45 disposed in pressure contact with the roller 44, and a sheet disposed on the upstream side of the fixing roller 44 and the pressure roller 45, and conveyed by the transfer conveyance unit 30, the fixing roller 44 and the pressure roller The front conveyance path 46 that guides between 45 and the downstream side of the fixing roller 44 and the pressure roller 45, and the sheet that has passed between the fixing roller 44 and the pressure roller 45 is guided to the third conveyance path 11. And a rear conveyance path 47.

  The third conveyance path 11 conveys the sheet on which the fixing process has been performed by the fixing unit 14 to the sheet discharge unit 3. A conveyance roller 48 is disposed at a predetermined position, and the discharge roller is disposed on the exit side. 24 is arranged.

  On the other hand, black toner, yellow toner, cyan toner, and magenta toner are respectively stored in the toner boxes 51 of the developing units 35 of the image forming units 26 to 29 of the image forming unit 7, and four toner boxes (covers) are provided. In the cooling unit 51, heat is dissipated by the friction of the sliding part of the stirring shaft and the blade when the toner is agitated. This heat may cause the toner to lose its fluidity and fail to form an appropriate image.

  Therefore, in this embodiment, for example, as shown in FIGS. 2 to 6 below, four toner boxes (objects to be cooled) 51 are cooled by one cooling fan 52.

  As shown in FIG. 2, a cooling fan (sirocco fan) 52 is attached to the right part in the apparatus main body 2. As shown in FIG. 3, four nozzles are formed in the air outlet 52 a through which the cooling air is blown from the cooling fan 52. The rear ends of the four flexible tubes 53 to 56 forming the air flow path for sending the cooling air blown from each nozzle are respectively inserted into the air blowing port 52a. As shown in FIGS. 4 to 7, the four flexible tubes 53 to 56 connect the cooling fan 52 and the image forming units 26 to 29, and further, the rear end of the bottom surface of the toner box 51. It extends to the part. In this state, the flexible tubes 53 to 56 are arranged such that their side surfaces (outer surfaces) are adjacent to each other along the longitudinal direction of the bottom surface of the toner box 51.

  Here, as shown in FIGS. 4 and 8, the four flexible tubes 53 to 56 are formed with a plurality of openings 53a to 53e, 54a to 54e, 55a to 55e, and 56a to 56e, respectively, on the upper side surfaces. Has been. Therefore, the flexible tubes 53 to 56 can blow cooling air toward the bottom surface of the toner box 51 from the plurality of openings 53a to 53e, 54a to 54e, 55a to 55e, and 56a to 56e, respectively. . In addition, as FIG. 8 shows, the front-end | tip of the flexible tubes 53-56 is obstruct | occluded with the cap 70, for example.

  The openings 53a to 53e, 54a to 54e, 55a to 55e, and 56a to 56e are arranged in order of opening area (cooling air flow) from the front side to the rear side of the bottom surface of the toner box 51 on the upper side of the flexible tubes 53 to 56. (Blowout area) is wide. That is, for example, in one flexible tube 53, the opening area of the opening 53e located on the front side of the bottom surface of the toner box 51 is the smallest, and the opening area gradually increases from the opening 53e to the opening 53a on the rear side. The opening area of the opening 53a located on the rear side of the bottom surface of the toner box 51 is the largest. Accordingly, the amount (flow rate) of the cooling air blown at the front side of the bottom surface of the toner box 51 is the smallest, the air amount gradually increases from the opening portion 53a to the opening portion 53e, and the air amount at the rear side of the bottom surface of the toner box 51. Is the most.

  Note that the openings 54a to 54e, 55a to 55e, and 56a to 56e formed in the other flexible tubes 54 to 56 are the same as described above, and the description thereof is omitted here. Further, cooling fans 60 and 61 for cooling other objects to be cooled are also attached to the right part in the apparatus main body 2, and these cooling fans 60 and 61 are connected via a duct (not shown), for example. It is connected to the object to be cooled.

  As shown in FIGS. 4 and 6, a frame side plate 57p of the main body frame 57 is disposed below each toner box 51 at the front portion of the apparatus main body 2, and on the front surface of the frame side plate 57p, Concave portions 57a to 57d are formed to extend in the left-right direction so as to fit and guide the flexible tubes 53 to 56 in four steps in the vertical direction. In addition to the frame side plate 57p of the main body frame 57, the recesses 57a to 57d can be formed on the side plate of the frame of the laser scanning unit 34, for example. Each of the flexible tubes 53 to 56 passes through the through holes 57e to 57h of the frame side plate 57p from the rear side from the position of the right part in the apparatus main body 2 to which the cooling fan 52 is attached, and inside the corresponding recesses 57a to 57d on the front side. To be inserted into the recesses 57a to 57d.

  The uppermost recess 57d extends to the left near the lower portion of the toner box 51 of the fourth image forming unit 29 for forming a magenta (M) toner image. The lower concave portion 57c extends to the left near the lower portion of the toner box 51 of the third image forming unit 28 for forming a cyan (C) toner image. Further, the lower recessed portion 57d extends to the left near the lower portion of the toner box 51 of the second image forming unit 27 for forming a yellow (Y) toner image. The lowermost concave portion 57a extends to the left to near the lower portion of the toner box 51 of the first image forming unit 26 for forming a black (B) toner image.

  The recesses 57 a to 57 d are curved upward from the vicinity of the corresponding toner box 51 toward the bottom surface of the toner box 51. Further, as shown in FIG. 6, each of the recesses 57 a to 57 d is formed with an insertion hole 57 i at its upper end portion. The flexible tubes 53 to 56 are inserted into the insertion holes 57 i and extend rearward in the apparatus main body 2 along the bottom surface (cooling portion) of the toner box 51.

  As described above, the air blowing port 52 a of the cooling fan 52 for cooling the toner box 51 in the apparatus main body 2 and the toner box 51 are connected by the flexible tubes 53 to 56, thereby the air blowing port of the cooling fan 52. Even when there is no room for providing a duct between the toner box 51 and the toner box 51, the flexible tubes 53 to 56 can be connected to the toner box 51 while being deformed so as to extend over the gap in the apparatus main body 2. . For this reason, the cooling air blown out from the plurality of openings 53a to 53e, 54a to 54e, 55a to 55e, and 56a to 56e opened on the upper side of the side surfaces of the flexible tubes 53 to 56 is indicated by arrows in FIGS. As indicated by a, the toner box 51 is sprayed on the entire bottom surface (cooled portion) in the longitudinal direction.

  At this time, the opening areas of the plurality of openings 53a to 53e, 54a to 54e, 55a to 55e, and 56a to 56e gradually increase from the front side to the rear side of the bottom surface of the toner box 51. For this reason, for example, heat is more likely to be accumulated on the rear side than the front side in the apparatus main body 2, and even if the temperature rise varies in the longitudinal direction of the toner box 51, the apparatus having a relatively high temperature rise. It is possible to increase the amount (flow rate) of cooling air blown on the rear side in the main body 2 and to reduce the amount of blown air on the front side where the temperature rise is relatively low. As a result, the entire longitudinal direction of the toner box 51 can be uniformly and uniformly cooled.

  In the present embodiment, since the four full-color toner boxes 51 can be cooled, it is possible to prevent the toner from losing its fluidity due to heat generated during the stirring of the toner, and a high-quality full-color image can always be obtained. Can be formed.

  Further, the flexible tubes 53 to 56 can be guided by being fitted into the recesses 57a to 57d of the frame side plate 57p of the main body frame 57, and the side surfaces of the flexible tubes 53 to 56 can be inserted into the insertion holes 57i of the frame side plate 57p. Since it can position correctly so that it may be arrange | positioned along the longitudinal direction of the bottom part (cooling part) of the box 51, the assembly | attachment of the flexible tubes 53-56 can be performed easily.

  Moreover, in this embodiment, although the shape of opening part 53a-53e, 54a-54e, 55a-55e, 56a-56e is made into the rectangle, it is good also as an ellipse in addition to this. When the aspect ratio is different, such as a rectangle or an ellipse, it is easy to change the opening area to a larger or smaller size by changing the dimension of the side (the length direction of the flexible tubes 53 to 56). It is advantageous to give variations to the.

  In the above-described embodiment, the four color image forming units 26 to 29 corresponding to full color are described as being cooled. However, for example, a monochrome (black) image forming unit and other components (cooled portion) are included. The present embodiment can also be applied in relation.

  Alternatively, it goes without saying that this embodiment can also be applied to cooling other parts to be cooled (for example, the photosensitive drum 32, the CPU, the polygon motor, the fixing unit 14, and the like).

[Other Embodiments]
In the above-described embodiment, the plurality of openings 53a to 53e, 54a to 54e, 55a to 55e, and 56a to 56e opened to the upper side of the flexible tube 53 to 56 side are the toner box on the upper side of the flexible tube 53 to 56 side. 51 may be configured by a plurality of opening holes (having substantially the same opening area) that are opened in order from the front side to the rear side of the bottom surface.

  FIG. 9 is a top view showing flexible tubes 53 to 56 that can be applied to other embodiments. In this case, the openings 53e to 56e on the front side of the bottom surface of the toner box 51 are configured to have the smallest number of small holes, and sequentially from the openings 53e to 56e on the front side to 53a to 56a on the rear side. Increasingly, the openings 53a to 56a on the rear side of the bottom surface of the toner box 51 are configured to have the largest number of small holes.

  Alternatively, in the above-described embodiment, the plurality of openings 53a to 53e, 54a to 54e, 55a to 55e, and 56a to 56e opened on the upper sides of the side surfaces of the flexible tubes 53 to 56 have the opening areas of the bottom surface of the toner box 51. However, the present invention is not limited to this, and the opening areas of the openings 53a to 56a opened on the rear side of the bottom surface of the toner box 51 are not limited to this. You may make it open wider than opening part 53b-56b, 53c-56c, 53d-56d, 53e-56e.

1 is an explanatory diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment. 2 is a perspective view showing a positional relationship between an image forming unit and a cooling fan of the image forming apparatus according to the present embodiment. FIG. FIG. 3 is a perspective view showing a positional relationship between an image forming unit and a cooling fan of the image forming apparatus according to the present embodiment and a connection state of flexible tubes. 1 is a side perspective view of an image forming apparatus according to an exemplary embodiment. It is a perspective view which shows the recessed part of the flame | frame side plate of the image forming apparatus which concerns on this Embodiment. FIG. 6 is an explanatory diagram showing a positional relationship between a toner box of an image forming unit of the image forming apparatus according to the present embodiment and a tip blowing portion of a flexible tube. 4 is an explanatory diagram showing a positional relationship between a toner box of an image forming unit of the image forming apparatus according to the present embodiment and an opening of a flexible tube. FIG. It is explanatory drawing which shows the structure of the opening part of the flexible tube of the image forming unit of the image forming apparatus which concerns on this Embodiment. It is explanatory drawing which shows the structure of the opening part of the flexible tube of the image forming unit of the image forming apparatus which concerns on other embodiment.

Explanation of symbols

2 Device main body 35 Developing unit 51 Toner box 52 Cooling fan 52a Air blowing port 53 to 56 Flexible tubes 53a to 53e, 54a to 54e, 55a to 55e, 56a to 56e Opening portion 57 Body frame 57a to 57d Recess

Claims (6)

A cooled portion provided over a range having a predetermined length in the apparatus body;
A cooling fan for supplying cooling air to the cooled part;
The air flow path that extends between the air outlet from which the cooling air is blown from the cooling fan and the cooled part, and extends to a position adjacent to the cooled part along its longitudinal direction,
An image forming apparatus comprising: an opening formed on an outer surface of the air flow path and for blowing out cooling air at a position facing the longitudinal direction of the cooled portion. The image forming apparatus according to claim 1.
The image forming apparatus according to claim 1, wherein a plurality of the opening portions are formed on the outer surface of the air flow path at positions facing each other along a longitudinal direction of the cooled portion. The image forming apparatus according to claim 2.
The plurality of openings are
2. An image forming apparatus according to claim 1, wherein the blowout areas of the cooling air are different from each other in accordance with a temperature rise distribution seen in the longitudinal direction of the cooled portion. The image forming apparatus according to claim 2 or 3,
The plurality of openings are
2. An image forming apparatus according to claim 1, wherein a cooling air blowing area is enlarged from the front side to the rear side of the portion to be cooled on the outer surface of the air flow path. 5. The image forming apparatus according to claim 1, wherein:
The air flow path is
It is a flexible tube that connects between an air outlet from which the cooling air is blown out from the cooling fan and the cooled part, and has an outer surface adjacent to the longitudinal direction of the cooled part. An image forming apparatus. The image forming apparatus according to claim 1,
The cooled part is
An image forming apparatus comprising: a plurality of image forming units that form magenta, cyan, yellow, and black toner images on an image carrier.

Images