JP5233489B2 - Waste heat structure and image forming apparatus - Google Patents

Description

  The present invention relates to a heat exhaust structure and an image forming apparatus.

  As is well known, one of image forming methods is an electrophotographic method. In this method, when an electrostatic latent image formed on a photoconductor corresponding to a latent image carrier is subjected to visible image processing by receiving toner from a developing device, the toner image is applied to a recording medium such as recording paper. The transferred toner image is fixed by a melting / penetrating action using heat and pressure in a fixing device.

By the way, the image forming apparatus includes a device serving as a heat source, such as the fixing device described above.
Equipment that becomes a heat source is not limited to a fixing device, but also includes electromagnetic equipment such as a motor and a clutch, and electric parts such as a microchip used for control. The heat from these heat sources is the image forming apparatus. This may cause an increase in the ambient temperature and may have a thermal adverse effect on the equipped equipment.

The image forming apparatus has a structure in which recording paper is loaded and unloaded from the front side of the apparatus main body facing the user side, or toner used in the developing device is replaced. Electrical components may be provided on the rear side. In the case of such a structure, heat tends to be accumulated on the rear side of the apparatus main body.
In particular, the paper discharge unit disposed in the vicinity of the fixing device has a high ambient temperature and is easily affected by heat from the fixing device in addition to the heat generated by the electrical components provided in the vicinity of the paper discharge unit. For this reason, if the temperature of the electrical component rises abnormally due to the influence of heat from the periphery of the electrical component in addition to the heat generated by the operation of the electrical component, there is a risk of malfunction or damage.

On the other hand, as the image forming apparatus, an in-body sheet discharge type in which a sheet discharge unit is provided in the image forming apparatus has been put into practical use in order to reduce the installation space (for example, Patent Document 1). .
This configuration employs a configuration in which a paper discharge tray is provided inside the image forming apparatus, instead of a paper discharge tray that protrudes outward from the image forming apparatus main body, which is a conventional paper discharge structure.
Furthermore, in order to reduce the installation space of the image forming apparatus, as described in Patent Document 1, a device for performing post-processing work such as stapling work for discharged recording paper is provided inside the image forming apparatus. A configuration for mounting in a paper discharge space is also known.

  In the configuration in which the post-processing device can be provided in the paper discharge space described above, the recording paper discharge portion to the paper discharge tray may be blocked by the post-processing device. There is a risk that heat from the installation location of the electrical component provided in the vicinity of the part may be difficult to escape to the outside.

In view of this, it is conceivable to suppress the temperature rise in the main body of the image forming apparatus by performing cooling using an air flow by exhaust or intake air for this portion.
As a typical configuration of cooling using airflow, there is forced cooling using a cooling fan (for example, Patent Documents 2 and 3).
In Patent Document 2, fans are provided on the front side and the rear side surface of the paper discharge unit in the image forming apparatus, respectively, to suck in outside air from the front side of the paper discharge unit, flow the sucked outside air above the fixing device, and discharge from the rear side surface of the apparatus The structure made to perform is disclosed.
In Patent Document 3, a fan capable of sucking outside air is provided in the vicinity of a writing device arranged in the vertical direction of the image forming apparatus below the sheet discharge tray, and the outside air sucked by the fan is disposed above the sheet discharge tray. The structure which exhausts with the fan located in is disclosed.

JP 2004-244225 A JP 2007-148102 A JP 2004-347770 A

  With the aim of providing the post-processing device disclosed in Patent Document 1 in the in-cylinder sheet discharge unit, as disclosed in Patent Documents 2 and 3, the periphery of the sheet discharge unit is cooled and the vicinity of the sheet discharge unit. In the configuration in which the temperature rise of the electrical components provided in the is prevented, there are the following new problems.

  In the configuration disclosed in Patent Document 2, it is necessary to change the direction of the outside air introduced above the paper discharge unit by the fan and then discharge it to the outside. There is a possibility that the temperature of the electrical component rises due to the warmed air when passing through the rear portion of the apparatus main body, that is, the exhaust position, that is, the installation position of the electrical component. As a result, there is a problem that the cooling of the electrical components by the outside air cannot be expected so much.

  On the other hand, in the configuration disclosed in Patent Document 3, it is necessary to provide a fan in the upper part of the discharge tray in addition to the fan in the lower position, and to provide a duct for changing the airflow direction in the fan in the upper part of the discharge tray. Therefore, it cannot be denied that the height of the image forming apparatus in the height direction with respect to the installation of the fan is increased. In addition, since the outside air introduced from one fan is exhausted by the other fan, similarly to the configuration disclosed in Patent Document 2, it receives heat from the fixing device arranged in the vicinity of the paper discharge tray. As a result, there is a problem that the electrical components located at the upper part of the paper discharge tray, that is, the rear part of the apparatus main body, are easily heated by the air when exhausted.

As a common problem in the cooling structure in the above-described patent document, a large installation space is required by increasing the air volume of the fan for taking outside air into the apparatus and increasing the air volume of the fan for discharging the taken outside air to the outside. There is.
In other words, it is important for the fan to prevent the outside air taken in from staying in the apparatus in order to prevent the temperature inside the apparatus from rising. For this reason, it is necessary to prevent the air flow in the apparatus from stagnation even if the flow of outside air is obstructed by the installation state of the electrical components disposed in the paper discharge unit or the rear part of the apparatus. . For this reason, an air volume is required so as not to stagnate the flow of the taken-in outside air even if an obstacle exists in the outside air flow path. For this reason, the air volume of the fan inevitably increases, and a large fan is required to satisfy this condition.

  An object of the present invention is to prevent an increase in size of the apparatus due to an increase in fan installation space and to be disposed at a relatively deep position in the apparatus in view of the problem related to cooling in the conventional image forming apparatus. An object of the present invention is to provide an exhaust heat structure and an image forming apparatus having a configuration capable of efficiently cooling many electrical components.

In order to achieve the above object, the present invention comprises the following arrangement.
(1) An exhaust heat structure having a configuration in which an electrical component such as a driving member used in the paper discharge unit is provided in the vicinity of the paper discharge unit that discharges the sheet.
A first flow path that takes in external air from outside and sets an airflow direction along an axial direction of a paper discharge roller provided in the paper discharge unit;
A second flow path that takes in outside air by a cooling means provided in the vicinity of the installation position of the electrical component and discharges it outside after directly contacting the electrical component with the external air;
The first and second flow paths are arranged in the same plane in the vertical direction, and merged by changing the direction at a position where the airflow from one flow path has passed the installation position of the electrical component. The exhaust heat structure is characterized by being configured to be continuous to the outside.

  The exhaust heat structure according to (1), wherein the electrical component includes at least a drive component for conveying a sheet discharged from the sheet discharge unit.

  The exhaust heat structure according to (1), wherein the electrical component includes at least a driving member for a conveyance path switching member that switches a sheet conveyance direction in the paper discharge unit.

  The exhaust heat structure according to (1), wherein the second flow path can take outside air toward an installation part of the electrical component.

  An image forming apparatus using the exhaust heat structure according to any one of (1) to (4).

  The paper discharge unit is configured as an in-cylinder paper discharge unit having an installation space in the apparatus main body, and a post-processing device for performing post-processing of paper discharge is detachably provided in the internal paper discharge unit. The image forming apparatus as described in (5) above.

  The image forming apparatus according to (5) or (6), wherein a heat radiating member is attached to a member used as the electrical component.

  According to the present invention, in addition to the first flow path for allowing the outside air to flow in the axial direction of the discharge roller provided in the discharge section, the second flow path for directly contacting the electrical component with the outside air is provided. Therefore, it is possible to cool the electrical components by the outside air independently of the outside air that has passed through the paper discharge unit. In addition, since these flow paths are merged and air is discharged to the outside, it is possible to share the space when different flow paths are provided, and thus it is possible to suppress an increase in the size of the apparatus.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is an external view of an image forming apparatus using an exhaust heat structure according to the present invention.
In FIG. 1, a printer corresponds to the image forming apparatus. However, the present invention is not limited to this, and it is also possible to target a facsimile machine, a copying machine, a printing machine, or a multifunction machine having these functions. .

In the image forming apparatus 1, the upper document scanning device 20 is disposed across the image forming unit in the vertical direction, and the paper feeding device 21 including a plurality of paper feeding trays 21 </ b> A and 21 </ b> B is disposed in the lower portion. The upper surface of the housing below the document scanning device 20 is provided with a paper discharge tray 1A that forms an in-body paper discharge unit, thereby eliminating the need for a paper discharge space outside the apparatus. An operation panel 20 </ b> A is provided on the front surface of the document scanning device 20.
The paper discharge tray 1A is configured by a space in which two side surfaces excluding the front surface of the apparatus main body, that is, the right side and the back side in FIG. 1 are surrounded by an exterior surface, and further surrounded by the document scanning device 20 and the image forming unit. Has been.

  Covers 22 and 23 that can be opened and closed are provided on the upper surface of the paper cassette 21A and on the wall surface in a direction perpendicular to the position on the front and side surfaces of the apparatus housing facing the user in the image forming apparatus 1, respectively. It can be opened for replacement or maintenance.

  2 and 3 are a front view and a diagram showing an internal configuration of the image forming apparatus 1 shown in FIG. 1. The image forming apparatus 1 is not shown in detail in FIG. A paper discharge unit in which the paper discharge tray 1A is located is provided above the sheet discharge tray 1A. The paper discharge unit is located above the image forming unit and outputs image formation on one side of the sheet (hereinafter referred to as single side output). A discharge tray 1A1 that is used at the time, and a discharge tray 1A2 that is an auxiliary tray that is positioned at the top of the discharge tray 1A1 and used for image formation output on both sides (hereinafter also referred to as double-sided output). Is provided.

  In order to discharge the sheet conveyed from the fixing device 25 to the position adjacent to the sheet discharge unit 1A in the upper portion of the image forming unit P as shown in FIG. A paper discharge unit 26 is provided.

  As described above with respect to the paper discharge unit 1A, the paper discharge unit 26 of this embodiment has discharge ports for discharging sheets toward the two paper discharge trays 1A1 and 1A2. The sheet on which the image has been formed is conveyed to the discharge roller 28 by switching the branch claw 27 and discharged to the discharge tray 1A1.

  On the other hand, at the time of double-sided output, by switching the branch claw 27, it is conveyed to the reverse roller 30 via the reverse relay roller 29, and is conveyed onto the paper discharge tray 1A2. When the trailing edge of the sheet passes through the reverse branching portion 31, the reverse roller 30 stops, and then reverse rotation is started after a predetermined time and is conveyed to the conveyance path 32 in the duplex unit. Then, after being conveyed again to the image forming unit 1, the reversing roller 30 is switched in the rotation direction and conveyed toward the discharge tray 1A2 to the discharge port.

  Although not shown, a stepping motor and a solenoid are provided behind the paper discharge unit 26. The stepping motor drives the reverse relay roller 28 and the reverse roller 30, and the solenoid drives the branch claw 27.

In this embodiment, as shown in FIGS. 4 and 5, a post-processing device 32 that performs post-processing on the image-formed sheet can be detachably provided in the space of the paper discharge unit 1 </ b> A. Yes. Hereinafter, the post-processing apparatus will be described with reference to FIG.
In FIG. 6, the post-processing device 32 is detachably connected to the conveyance path on the reverse roller 30 side.

The post-processing device 32 performs post-processing for performing a series of processing of punching holes in an image-formed sheet, aligning a plurality of sheets, stapling, and discharging the bound sheet bundle to the stack tray 32A. Device. As shown in FIG. 6, the post-processing device 32 includes a punch hole punching unit 320, a staple processing unit 321, and a stack tray 32 </ b> A that can expand and contract to accommodate a large size sheet.
The post-processing device 32 is an optional equipment of the image forming apparatus 1 that uses the in-body paper discharge method, and is detachable from the space of the paper discharge unit 1A.

  As a method of mounting the post-processing device 32 on the image forming apparatus 1, first, the paper discharge tray 1A1 installed in the space of the paper discharge unit 1A and the paper discharge tray 1A2 as an auxiliary tray are removed. Next, the post-processing device 32 is inserted into the space of the paper discharge unit 1A along the arrow direction shown in FIG. At this time, positioning is performed by aligning positioning pins (not shown) of the post-processing device 32 with positioning holes (not shown) provided in the rear side of the machine and the right front column (indicated by reference numeral 24A for convenience). Then, the mounting is completed by screwing the screw holes provided in the back side of the apparatus and the left side surface of the image forming apparatus.

  When the post-processing device 32 is mounted, the conveyance path via the discharge roller 28 used at the time of single-sided output in the paper discharge unit 26 is blocked, so the branch claw 27 is always attached to the discharge roller 30 used at the time of double-sided output. The swinging position is maintained in the direction in which the transport path of the directed sheet is set.

For the image forming apparatus 1 configured as described above, the exhaust heat structure which is a feature of the present invention will be described as follows.
FIG. 7 is an external view showing an intake port and an exhaust port used for exhaust heat in the apparatus main body when the apparatus main body is viewed from the back side. In FIG. An intake port 22A formed in the front cover 22 is provided on the side portion of the side indicated by the symbol F), and an exhaust port (designated by the symbol EP for convenience) is provided on the back surface (the side indicated by the symbol R) of the apparatus housing. ) Is provided. Further, on the side surface of the apparatus housing, an air inlet 23A is provided at the rear portion of the side cover 23 that covers the double-sided conveyance unit. Each intake port and exhaust port is formed with an armor door shape or a slit so that a finger or the like can be prevented from entering from the outside.

On the other hand, as shown in FIGS. 8 and 9, a configuration for cooling and exhausting heat from the paper discharge unit (portion 26 in FIG. 3) is provided inside the apparatus housing.
FIG. 8 is a perspective view showing the periphery of the branching claw 27 in the paper discharge unit 26 (see FIG. 3). In FIG. 8, the paper discharge unit 26 is equipped with an intake fan 33 on the front side of the apparatus housing. And the exhaust fan 34 (refer FIG. 9) is equipped in the apparatus housing back | inner side.

  The intake fan 33 can take in outside air from the intake port 22 </ b> A provided in the front cover 22 of the apparatus housing shown in FIG. 7, and in the axial direction of the reversing roller 30 provided in the paper discharge unit 26. The outside air flows along the exhaust fan 34 (see FIG. 9).

In the range from the intake fan 33 to the exhaust fan 34, the first flow path FA that moves the outside air above the discharge guide 26A in the discharge unit 26 along the axial direction of the reversing roller 30 is configured as described above. It has come to be.
The outside air that passes through the first flow path FA passes through the paper discharge guide 26A in the paper discharge unit 26, so that the heat around the paper discharge guide 26A can be released to the outside. As a result, it is possible to prevent a plurality of sheet detection switches (not shown) arranged inside the paper discharge unit 26 from being damaged by heat from the fixing device 25.

FIG. 9 is a plan view of the paper discharge unit 26. In FIG. 9, the longitudinal direction of the paper discharge unit 26, in other words, the axial direction one side of the reversing roller 30 is the outside air inlet of the first flow path FA described above. The above-described intake fan 33 is disposed on the outside air inlet side.
A front side plate 35 and a rear side plate 36 are respectively provided on the longitudinal direction of the paper discharge guide 26A in the paper discharge unit 26, in other words, on both axial sides of the reversing roller 30. A fan 33 is provided.
10A is a front view of the front side plate 35, and FIG. 10B is a front view of the rear side plate 36. In FIG. 10, the front side plate 35 and the rear side plate 36 each include a plurality of outside air passing portions. The slit-shaped holes 35A and 36A are formed.

In FIG. 9, an exhaust fan 34 provided in the duct 37 is disposed in front of the moving direction of the airflow that has passed through the rear side plate 36.
On the other hand, in the vicinity of the duct 37, that is, behind the rear side plate 36, although not shown in detail, a stepping motor for driving the reverse roller 30 and the reverse relay roller 29 (see FIG. 3) or the branching claw 27 (see FIG. 3). An electrical component such as a solenoid for swinging and driving is disposed.

In the present embodiment, in order to suppress the temperature rise of the electrical component described above, a configuration for exhausting heat of the electrical component independently is provided separately from the first flow path FA described above.
In FIG. 9, a protective cover 38 is provided in the vicinity of the rear side plate 36 to prevent the user's hand from touching from the paper discharge outlet side of the paper discharge unit 26.

The protective cover 38 is integrated with the paper discharge unit 26 on the side of the paper discharge port from which the sheet is discharged on one side perpendicular to the first flow path FA. It is integrated and incorporated through.
As shown in FIG. 11, the protective cover 38 is integrated with an intake fan 39 that is different from the intake fan 33 positioned on the outside air inlet side in the first flow path FA. It can be taken in toward the installation position of electrical parts.

  The flow path of the outside air by the intake fan 39 is set independently of the first flow path FA as indicated by the symbol FB in FIG. 9, and the outside air taken in toward the electrical component is opposite to the take-in side. The direction is changed by the exterior panel 41 located on the side, and the first flow path FA is merged at the front side of the duct 37, that is, at the position passing through the installation position of the electrical component.

The merge direction of the first flow path FA and the second flow path FB is substantially the same direction, but the second flow path FB reaching the merge position is in a state of crossing the first flow path FA. ing. For this reason, in this embodiment, the flow rate (Qx) of the airflow flowing through the second flow path FB is set to the following relationship with respect to the flow rate (Qa) of the airflow flowing through the first flow path FA. Note that the flow rate of the air flow in the exhaust fan 34 is indicated by (Qb).
Qb ≧ Qa + Qx
By setting this relationship, the airflow flowing through the first flow path FA is somewhat disturbed by the airflow flowing from the second flow path FB, but the airflow flowing through both flow paths is merged and exhausted. It is discharged to the outside by the fan 34 (indicated by an arrow FC in FIG. 9). In addition, in FIG. 9, the magnitude | size of the arrow which shows an airflow direction represents the magnitude | size of flow volume.

  In the configuration as described above, the first and second flow paths FA and FB can be provided in substantially the same plane in the vertical direction, and an increase in size in the height direction in the apparatus can be suppressed. .

  In addition, since the electrical component is cooled by the outside air flowing through the dedicated flow path intended for this, the first flow path FA is compared with the cooling by the external air taken in from the first flow path FA. The cooling effect is enhanced by the amount of air that is not warmed in the paper discharge unit like the outside air flowing through the.

  In addition, a cooling effect can further be heightened by attaching the heat radiating member for raising the contact area with an airflow, for example, a heat radiating fin, etc. to an electrical component.

  On the other hand, when the post-processing device 32 is equipped, the reversal position of the airflow in the second flow path FB is the member used for attaching the post-processing device 32 instead of the exterior cover 40 or the post-processing. The side end wall of the device 32 (the right side of the post-processing device 32 in FIG. 5) functions.

The present inventor has observed the change in temperature according to the operation time for the stepping motor and the solenoid mentioned as the electrical components using the configuration shown in the above embodiment, and obtained the following results.
When 3 hours of continuous printing was performed using only the first flow path FA in the configuration shown in the above embodiment, the temperatures of the stepping motor and the solenoid reached 61.8 ° C. and 97.1 ° C.
On the other hand, when the second flow path FB was merged with the first flow path FA, the temperature of the electrical component decreased to 55.2 ° C. and 75.7 ° C.

1 is an external view of an image forming apparatus using an exhaust heat structure according to the present invention. FIG. 2 is a front view of the image forming apparatus illustrated in FIG. 1. FIG. 2 is a diagram illustrating a main part of an internal configuration of the image forming apparatus illustrated in FIG. 1. FIG. 3 is a view corresponding to FIG. 2 when a post-processing device is provided in the image forming apparatus shown in FIG. 1. It is a figure which shows the mounting process of the post-processing apparatus shown in FIG. FIG. 5 is a diagram illustrating an internal configuration of the image forming apparatus when the post-processing apparatus illustrated in FIG. 4 is provided. FIG. 2 is an external view illustrating a configuration of a suction / discharge port in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a perspective view for explaining a peripheral structure of a paper discharge unit used in the image forming apparatus shown in FIG. 1. FIG. 9 is a plan view showing a peripheral portion of the paper discharge unit shown in FIG. 8. FIG. 10 is a front view of a front side plate and a rear side plate used in the heat exhaust structure for the paper discharge unit shown in FIGS. 8 and 9. FIG. 10 is a perspective view showing a protective cover and an exhaust fan used in the heat exhaust structure for the paper discharge unit shown in FIGS. 8 and 9.

Explanation of symbols

1 Image forming apparatus.
1A Paper discharge unit 26 Paper discharge unit 27 Branch claw 30 Reverse roller
33 Intake fan 34 Exhaust fan 35 Front plate 36 Rear plate 38 Protective cover 39 Intake fan 40 Exterior cover used for airflow direction change P Image forming unit FA First flow path FB Second flow path

Claims (7)

An exhaust heat structure having a configuration in which an electrical component such as a driving member used in the paper discharge unit is provided in the vicinity of the paper discharge unit that discharges the sheet,
A first flow path that takes in external air from outside and sets an airflow direction along an axial direction of a paper discharge roller provided in the paper discharge unit;
A second flow path that takes in outside air by a cooling means provided in the vicinity of the installation position of the electrical component and discharges it outside after directly contacting the electrical component with the external air;
The first and second flow paths are arranged in the same plane in the vertical direction, and merged by changing the direction at a position where the airflow from one flow path has passed the installation position of the electrical component. The exhaust heat structure is characterized by being configured to be continuous to the outside.   The exhaust heat structure according to claim 1, wherein the electrical component includes at least a driving component for conveying a sheet discharged from the sheet discharge unit.   The exhaust heat structure according to claim 1, wherein the electrical component includes a drive member for a conveyance path switching member that switches at least a sheet conveyance direction in the paper discharge unit.   The exhaust heat structure according to claim 1, wherein the second flow path can take outside air toward an installation part of the electrical component.   An image forming apparatus using the exhaust heat structure according to claim 1.   The paper discharge unit is configured as an in-cylinder paper discharge unit having an installation space in the apparatus main body, and a post-processing device for performing post-processing of paper discharge is detachably provided in the internal paper discharge unit. The image forming apparatus according to claim 5.   The image forming apparatus according to claim 5, wherein a heat radiating member is attached to a member used as the electrical component.

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