JP2006145132A - Cooling device, and image forming device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device capable of smoothly sending air even in a bent part of a duct in regard to a cooling device cooling an apparatus interior. <P>SOLUTION: The cooling device 40 is provided in a developing machine periphery of an image forming part of the image forming device which is an apparatus. The cooling device 40 is provided with the duct 50 for communicating air, and an intermediate fan 41 which is an axial fan forcibly generating an air flow in the duct 50. The intermediate fan 41 is provided in a neighborhood of a second bent part 53 changing a direction of the air flow of the duct 50. An axis 41a of the intermediate fan 41 does not match with neither of a center line 54a of an upstream side portion 54 from the intermediate fan 41 and a center line 55a of a downstream side portion 55, and it is arranged in a direction sending air from the upstream side portion 54 toward the downstream side portion 55 of the duct 50. By this the air in an upstream side of the intermediate fan 41 can be smoothly sent to a downstream side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling device used for cooling the inside of an apparatus. The present invention also relates to an image forming apparatus equipped with this cooling device.

  In an image forming apparatus represented by a copier or a printer, a heat source is built in at least one roller of a roller pair forming a nip, and a sheet carrying an unfixed toner image in the nip of the roller pair heated by the heat source A heat roller fixing method is widely used in which toner is fixed to a sheet by inserting the toner. In addition to the heat roller of the fixing unit, various components related to the temperature rise inside the apparatus, such as a driving device such as a motor, an electrical component, a sliding part of the roller, and the like are provided.

  In recent years, image forming apparatuses are strongly required to increase the image quality and speed. However, a certain amount of heat is required to fix the toner on the paper, and as the speed increases, there is a problem that the temperature rise particularly around the fixing portion becomes severe. In order to release the heat inside the apparatus, it is necessary to provide a cooling device including an intake duct or an exhaust duct that leads to the vicinity of the heat source.

On the other hand, various members for forming an image on a sheet are provided inside the image forming apparatus, and the internal structure thereof is becoming more and more complicated due to the recent progress of light weight and downsizing. For this reason, the duct provided in the cooling device may be forced to include a bent portion bent at a steep angle. Here, an example of a cooling device including a duct bent at a steep angle can be seen in Patent Document 1.
Japanese Patent Laid-Open No. 11-287544 (page 3-4, FIG. 5)

  FIG. 6 is a schematic horizontal sectional partial enlarged top view showing an example of a duct of a conventional cooling device. White arrows in the figure indicate the direction of air flow. The cooling device 100 includes a duct 110 that circulates air and an axial fan 101 that forcibly generates airflow. The duct 110 includes a bent portion 111 that changes the direction of airflow at an angle that is substantially perpendicular. The axial fan 101 has an axial direction that coincides with the direction of airflow flowing in and out, and is fixed inside the duct 110. The axial fan 101 is provided in the vicinity of the bent portion 111 of the duct 110 so that its axis 101a coincides with the center line 112a of the upstream portion 112 of the duct 110 from the axial fan 101. .

  The cooling device 100 having such a configuration is a configuration that is commonly used in this type of cooling device (exhaust device) as seen in Patent Document 1. However, in this configuration, when an air flow is generated by the axial fan 101, the air travels while colliding from the front with the wall surface 113 b of the duct 110 facing the axial fan 101 in the portion 113 immediately downstream of the axial fan 101. It will be. For this reason, it becomes difficult to flow air through the duct 110 smoothly. Therefore, since cooling efficiency falls, the possibility that the temperature inside the device will rise and have a great adverse effect will increase.

  The present invention has been made in view of the above points, and in a cooling device that includes a duct and an axial fan in the duct and cools the inside of the apparatus, air can be smoothly flowed even in a bent portion of the duct. The object is to provide a possible cooling device. It is another object of the present invention to provide an image forming apparatus equipped with such a cooling device.

  In order to solve the above-described problems, the present invention provides a duct for circulating air, an axial fan provided inside the duct and in the vicinity of a bent portion that changes the direction of airflow, and forcibly generates airflow. A cooling device that circulates air between the inside and outside of the equipment and cools the inside of the equipment, wherein the axial fan has an axis that is the center line of the upstream portion from the axial fan of the duct, The air flowing in the upstream portion of the duct is arranged so as to be directed to the downstream portion of the duct that does not coincide with each of the center lines of the downstream portion.

  Further, the axial fan has an angle that bisects an internal angle formed by the center line of the upstream portion of the duct and the center line of the downstream portion of the bent portion of the duct from each center line. It was decided that the fan rotation surface was inclined.

  In the present invention, the cooling device is mounted on the image forming apparatus.

  According to the configuration of the present invention, in the cooling device that includes the duct and the axial fan in the duct and cools the inside of the equipment, the axial fan has an axial line in the upstream portion from the axial fan of the duct. Since the center line and the center line of the downstream part do not coincide with each other, and the air flowing through the upstream part of the duct is arranged in the direction directed to the downstream part of the duct, the axial flow Immediately downstream of the fan, air can strike the duct wall facing the axial fan at a sharp angle. Thereby, it becomes possible to flow air smoothly and it is possible to improve the cooling efficiency. Therefore, it is possible to prevent a temperature rise inside the device and maintain a stable operation state.

  Further, in the cooling device configured as described above, the axial fan has an angle that bisects the internal angle formed by the center line of the upstream portion of the duct and the center line of the downstream portion at the bent portion of the duct. Since the rotation surface of the fan is inclined with respect to the center line, air can flow more smoothly in the duct. Thereby, since cooling efficiency can be improved, a much more reliable cooling device can be obtained.

  In the present invention, since the cooling device is mounted on the image forming apparatus, air can flow smoothly even at the bent portion of the duct, so that the cooling efficiency is improved and the stable operation state is maintained. It is possible to obtain an image forming apparatus capable of performing the above.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Here, an image forming apparatus is taken as an example of equipment, and the cooling apparatus according to the present embodiment is used to cool a developing device that supplies toner to an image carrier.

  First, the image output operation of the image forming apparatus equipped with the cooling device of the present invention will be described while explaining the outline of the structure with reference to FIG. FIG. 1 is a schematic vertical sectional front view of an image forming apparatus. A solid line arrow in the drawing indicates a sheet conveyance path and a conveyance direction.

  In FIG. 1, a cassette type paper feed unit 3 is disposed at the bottom of the main body 2 of the image forming apparatus 1. In the cassette type paper feeding section 3, paper P such as cut paper before printing is stacked and stored, and the paper P is separated and sent out one by one. The cassette type paper feed unit 3 includes a three-stage paper cassette 4. The paper feed cassette 4 can be pulled out by sliding to the front side with respect to the main body 2.

  A manual paper feeder 5 is provided outside the upper right side of the main body 2. On the manual sheet feeding unit 5, paper P having a size that is not in the cassette type sheet feeding unit 3 or a sheet to be fed one by one such as an OHP sheet is placed.

  The image forming apparatus 1 includes a paper transport unit 6 therein. The sheet conveyance unit 6 is located on the right side in the sheet feeding direction in terms of the cassette type sheet feeding unit 3, and is located on the left side in terms of the manual sheet feeding unit 5. The paper P sent out from the cassette type paper feed unit 3 is conveyed vertically upward along the side surface of the main body 2 by the paper transport unit 6, and the paper P sent out from the manual paper feed unit 5 is transported horizontally, and will be described later. Part 10 is reached.

  A registration roller 7 is provided on the downstream side in the paper conveyance direction of the paper conveyance unit 6 and immediately upstream of the transfer unit 10. The registration roller 7 feeds the paper P toward the transfer unit 10 in synchronization with a toner image formed by the image forming unit 20 described later while correcting the oblique feeding of the paper P.

  A document feeding portion 8 is provided on the upper surface of the main body 2 of the image forming apparatus 1, and an optical portion 9 is provided below the document feeding portion 8. When a user copies a document, a document on which an image such as a character, a figure, or a pattern is drawn is loaded on the document feeding unit 8. The document feeding unit 8 separates the documents one by one and feeds them, and the optical unit 9 reads the image data.

  An image forming unit 20 and a transfer unit 10 are provided on the downstream side of the registration roller 7 in the sheet conveying direction and below the optical unit 9. In the image forming unit 20, an electrostatic latent image of a document image is formed on the surface of the photosensitive drum 21 that is an image carrier based on the image data read by the optical unit 9. A toner image is formed from the electrostatic latent image by the developing device 30, and the toner image is transferred by the transfer unit 10 to the pre-printing paper P sent in synchronization by the registration roller 7.

  A fixing unit 11 is provided on the downstream side of the transfer unit 10. The paper P carrying the unfixed toner image in the transfer unit 10 is sent to the fixing unit 11 where the toner image is fixed by the heat roller.

  A discharge / branch unit 12 is provided on the downstream side of the fixing unit 11 and in the vicinity of the left side surface of the main body 2. The sheet P discharged from the fixing unit 11 is discharged from the discharge / branch unit 12 to a sheet receiving tray outside the apparatus when duplex printing is not performed.

  A duplex printing unit 13 is provided below the portion from the image forming unit 20 to the discharge / branch unit 12 and above the cassette type sheet feeding unit 3. When performing duplex printing, the paper P discharged from the fixing unit 11 is sent to the duplex printing unit 13 through the discharge / branch unit 12. The paper P sent to the duplex printing unit 13 is subsequently switched in the feeding direction and sent again to the transfer unit 10 via the paper transport unit 6 and the registration roller 7.

  In such an image forming apparatus 1, the cooling device of the present invention is provided around the developing device 30 provided in the image forming unit 20.

  Next, the detailed configuration of the cooling device will be described with reference to FIGS. 2 to 4 in addition to FIG. FIG. 2 is a top view of a model horizontal section around the image forming unit, and FIG. 3 is a right side view of the model vertical section. FIG. 4 is a partially enlarged top view of a model horizontal cross section of the duct of the cooling device. In FIG. 3, drawing of the photosensitive drum 21 and the fixing unit 11 is omitted. The lower side in FIG. 2 is the front side of the image forming apparatus 1 and the left side in FIG. Moreover, in FIGS. 2-4, the white arrow in a figure shows the direction through which air flows.

  As shown in FIGS. 1 and 2, the image forming unit 20 is provided with a photosensitive drum 21 that is an image carrier. Around the photosensitive drum 21, a developing device 30, a cleaning device 22, and the like. Is provided.

  The photosensitive drum 21 includes a conductive roller-like substrate made of aluminum or the like, and a photosensitive layer provided on the outside thereof. The photosensitive layer is provided with amorphous silicon which is an inorganic photoconductive material by vacuum deposition or the like. The photosensitive drum 21 is rotated by a driving device (not shown) so that the peripheral speed thereof is the same as the paper conveyance speed (for example, 175 mm / sec).

  As shown in FIGS. 1 and 2, the developing device 30 is provided with a developing roller 31 that is a roller-shaped rotating body in the vicinity of the photosensitive drum 21. The developing roller 31 is supported by the housing 32 via a bearing (not shown). The developing roller 31 is a non-contact type of the photosensitive member, and a bias having the same polarity as the charging polarity of the photosensitive drum 21 is applied. The developing roller 31 charges the toner, which is a developer, and causes it to fly to the electrostatic latent image on the surface of the photosensitive drum 21 to develop the electrostatic latent image. As the toner, a magnetic or non-magnetic one-component toner or a two-component toner obtained by mixing a magnetic carrier and an insulating toner is used. The developing roller may be a photoreceptor contact type.

  The cleaning device 22 transfers the toner image formed on the surface of the photosensitive drum 21 onto the paper P, and then removes the toner remaining on the surface of the photosensitive drum 21 to perform cleaning. The toner removed from the surface of the photosensitive drum 21 is collected in the housing of the cleaning device 22 and then conveyed to the outside.

  As shown in FIGS. 2 and 3, a cooling device 40 is provided around the developing device 30 of the image forming unit 20. The cooling device 40 includes a duct 50, an intermediate fan 41, and an exhaust fan 42.

  The duct 50 is disposed at a position from above the developing device 30 to the rear part of the main body 2. The duct 50 includes an intake port 51 having a length substantially the same as the axial length of the developing device 30 at a location above the developing device 30. In order to make it easy for heat around the developing device 30 to escape, the intake port 51 faces downward, that is, toward the developing device 30 and is located immediately above the housing 32 of the developing device 30. The duct 50 includes a first bent portion 52 that changes the direction of the bent airflow along the inner frame 2b at the rear of the developing unit 30 and the direction of the bent airflow on the back side of the main body 2 near the fixing portion 11. And a second bent portion 53 that changes. The first bent portion 52 and the second bent portion 53 are bent at a right angle. The duct 50 passes through the inner frame 2b in the vicinity of the second bent portion 53, and further continues toward the back side of the main body 2.

  As shown in FIGS. 2 and 4, an intermediate fan 41 is disposed in the vicinity of the second bent portion 53. The intermediate fan 41 is an axial fan that forcibly generates an air flow in the duct 50 in the middle from the suction portion to the blow-out portion of the duct 50, and is fixed inside the duct 50. The axis 41 a of the intermediate fan 41 does not coincide with each of the center line 54 a of the upstream portion 54 and the center line 55 a of the downstream portion 55 from the intermediate fan 41, and the upstream portion of the duct 50. The air flowing through 54 is arranged in a direction toward the downstream portion 55. More specifically, the intermediate fan 41 has an inner angle of 90 ° formed by the center line 54a of the upstream portion 54 of the duct 50 and the center line 55a of the downstream portion 55, and an angle of 45 ° that bisects each center. The rotation surface of the fan is inclined from the line. Thereby, the air on the upstream side of the intermediate fan 41 can be smoothly sent to the downstream side.

  As shown in FIG. 2, two exhaust fans 42, which are axial fans, are horizontally arranged at the downstream end of the duct 50. These exhaust fans 42 forcibly generate an air flow in the duct 50 at the downstream end portion of the duct 50, and pass through the opening 2 c provided in the exterior frame 2 a on the back surface side of the main body 2. Air is discharged to the outside of the main body 2. Therefore, the air having the heat around the developing device 30 can be released to the outside of the image forming apparatus 1 by such a cooling device 40.

  Next, the influence on the temperature change around the developing roller 31 when the cooling device 40 having the above configuration is operated will be described with reference to FIG. FIG. 5 is a table showing the influence of the cooling device of the present invention on the temperature change before and after the developing roller. In addition, the result at the time of operating the conventional cooling device shown in FIG. 6 with respect to the cooling device of this invention is described in FIG. 5 as a comparative example. The temperature data shown in FIG. 5 shows the temperature rise from the start of printing to the end of printing on the front side and the back side in the axial direction of the developing roller 31 when two-sided copies of A4 size paper P are continuously printed. Show.

  According to FIG. 5, the axial line 101a of the axial fan 101 is compared with the conventional cooling device 100 (see FIG. 6) which is a comparative example in which the duct 110 coincides with the center line 112a of the upstream portion 112 from the axial fan 101. In the case of the cooling device 40 of the present invention (see FIG. 4), it can be seen that the temperature rise is small on both the front side and the rear side of the developing roller 31.

  Thus, in the cooling device 40 that includes the duct 50 and the intermediate fan 41 that is an axial fan in the duct 50 and cools the inside of the image forming apparatus 1 that is a device, the intermediate fan 41 has its axis line 41a does not coincide with each of the center line 54a of the upstream portion 54 and the center line 55a of the downstream portion 55 from the intermediate fan 41 of the duct 50, and the air flowing through the upstream portion 54 of the duct 50 is ducted. 50 is arranged in a direction facing the downstream portion 55 of the air, so that the air can strike the wall surface of the duct 50 facing the intermediate fan 41 at a sharp angle immediately downstream of the intermediate fan 41. . Thereby, it becomes possible to flow air smoothly and it is possible to improve the cooling efficiency. Therefore, it is possible to prevent the temperature inside the image forming apparatus 1 from rising and maintain a stable operation state.

  Further, the intermediate fan 41, which is an axial fan, has two internal angles formed by the center line 54a of the upstream portion 54 and the center line 55a of the downstream portion 55 of the duct 50 at the second bent portion 53 of the duct 50. Since the rotation surfaces of the fans are inclined from the respective center lines at equal angles, air can flow more smoothly in the duct 50. Thereby, since cooling efficiency can be improved, the cooling device 40 with higher reliability can be obtained.

  Furthermore, since the cooling device 40 is mounted on the image forming apparatus 1, the cooling efficiency is enhanced by allowing air to flow smoothly even in the second bent portion 53 of the duct 50, and a stable operating state is maintained. An image forming apparatus 1 capable of performing the above can be obtained.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in a cooling device including a duct provided with a bent portion for changing the direction of airflow.

1 is a schematic vertical sectional front view of an image forming apparatus equipped with a cooling device according to an embodiment of the present invention. It is a model horizontal cross-section part top view which shows an image formation part periphery. It is a model vertical cross-section part right view which shows an image formation part periphery. It is a model horizontal cross-section part enlarged top view of the duct of a cooling device. It is a table | surface which shows the influence which the cooling device of this invention has on the temperature change before and behind a developing roller. It is a model horizontal cross-section part enlarged top view which shows an example of the duct of the conventional cooling device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body 2a Exterior frame 2d Internal frame 20 Image forming part 21 Photosensitive drum 30 Developing part 31 Developing roller 40 Cooling device 41 Intermediate fan (axial fan)
41a Axis 42 Exhaust fan 50 Duct 52 First bent portion 53 Second bent portion 54 Upstream portion 54a Center line 55 Downstream portion 55a Center line

Claims (3)

A duct that circulates air, and an axial flow fan that is provided in the vicinity of the bent portion that changes the direction of the airflow and forcibly generates an airflow, between the inside and the outside of the device. In a cooling device that circulates air and cools the inside of the equipment,
The axial fan has an axis that does not coincide with the center line of the upstream part and the center line of the downstream part from the axial fan of the duct, and the air flowing through the upstream part of the duct A cooling device, wherein the cooling device is arranged in a direction directed to a downstream portion of the duct.   The axial fan has an angle that bisects the internal angle formed by the center line of the upstream portion of the duct and the center line of the downstream portion of the duct at the bent portion of the duct. The cooling device according to claim 1, wherein the rotation surface is disposed with an inclination.   An image forming apparatus comprising the cooling device according to claim 1.

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