JP2006337589A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having such a configuration that a required air flow for heat radiation can be secured and simultaneously noise generated when the air flow for heat radiation is secured is suppressed as well. <P>SOLUTION: A forced-air intake means 110 for taking in outside air is provided in a writing unit 3 installed in the housing of the image forming apparatus and a writing light exit opening 3A through which the taken-in air can be ejected toward an image forming unit side is provided in the writing unit 3. The image forming apparatus is configured so that the writing unit 3, an image forming unit 2 and a fixing device 14 are arranged from the upstream side to the downstream side in the moving direction of the taken-in air. In addition, a forced-air intake means 102 for cooling the heat generating source 100 of the fixing device 14 is provided in the middle in the moving direction of the air and a forced evacuation means 111 for discharging the air from the inside of the housing is provided near the fixing device 14 located on the downstream side in the moving direction, so that hot air from the fixing device 14 does not affect members on the upstream side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an exhaust heat structure in the apparatus.

  As is well known, one of image forming methods is an electrophotographic method. In this system, 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 recorded on 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.

The fixing device uses a fixing roller with an internal heat source and a pressure roller to heat and fix the recording sheet while nipping and conveying it. There is a configuration to use.
When the surface of the belt used in this configuration is heated not from the inside of the roller but from the outside, the rise of the surface temperature of the belt that contacts the unfixed toner can be accelerated. Therefore, an electromagnetic induction method can be used as an external heating source (Non-Patent Document 1).

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

For example, since toner is used as a developer in the developing device, there is a possibility that the desired developer supply control cannot be performed due to the solidification of the toner due to the temperature rise in the developing device.
In addition, in an optical system, a resin-made optical lens such as an fθ lens is often used. Therefore, a normal imaging optical path changes due to thermal deformation or the like, and a defective image such as a color shift is obtained. There is a risk that it will be.

  Therefore, conventionally, a configuration for discharging the heat generated in the fixing device to the outside has been adopted. As this configuration, it is a general configuration to arrange a heat exhaust fan near the fixing device (for example, Patent Document 1).

  Moreover, although it is not for exhaust heat, there is also a configuration in which ozone generated from the charging device is discharged using a fan (for example, Patent Document 2).

  Furthermore, in order to prevent thermal deformation of the optical system parts, a configuration has been proposed in which each optical device is collectively provided with a duct that can be arranged in the airflow passage, and heat isolation and heat dissipation are performed using the duct (for example, Patent Documents). 3).

  On the other hand, as a configuration for preventing the heat generated in the above-described fixing device from spreading to the periphery thereof, when the fixing device is disposed in the vicinity of the installation position of the toner replenishing tank used in the toner replenishing portion, the distance between the two devices is reduced. In addition to the heat insulating member and the heat insulating member, there is a structure in which ventilation means is provided (for example, Patent Document 4), or a structure in which both are separated (for example, Patent Document 5).

July 14, 2000 Post office of the Ministry of Internal Affairs and Communications “Title: Document copy printing machine using electromagnetic induction heating added to type designation” (materials for consultation with the Radio Control Council regarding partial revision of the Radio Law Enforcement Regulations) JP-A-11-231760 (paragraph "0009" column) Utility Model Registration No. 2554613 (page 2, left column, lines 22-32) JP 2001-22151 A (paragraph “0025” column) JP 2003-326107 A (paragraphs “0067” and “0069” columns) Japanese Patent Laying-Open No. 2003-202728 (FIG. 1)

In recent years, it has been desired to shorten the time required to start up the image forming apparatus, and there is a tendency that the fixing apparatus also needs to shorten the warm-up time until it reaches a predetermined fixing temperature.
For this reason, in addition to using a belt having a small heat capacity, a heating method that quickly rises to the heating temperature may be used. As this heating method, there is the above-described electromagnetic induction heating (induction heating (IH)) method. .

  In the electromagnetic induction heating method, a metal housing containing a magnetic force generating coil is disposed in the vicinity of the belt surface, and radiant heat from the housing side is generated by using eddy currents generated by magnetic lines transmitted through the metal housing. Thus, the belt can be heated.

However, when the electromagnetic induction heating method is used, there are the following problems.
When heating is performed from the side of the metal housing disposed in the vicinity of the belt surface, the heat retention on the roller side is small unlike the case where the heating source for the belt is provided on the roller side. For this reason, the heat from the metal housing used for electromagnetic induction heating easily spreads to the peripheral part, leading to a temperature rise in the peripheral space. As a result, as described above, the optical system and the developing device side are adversely affected. Effect.

As countermeasures against abnormal temperature rise in the equipment, there is exhaust heat due to air flow generation using a fan, etc., but in order to increase the exhaust heat efficiency, it is overheated by increasing the air volume and air flow speed (pressure) from the used fan. It is important to expel air to the outside quickly. However, when such a configuration is adopted, the following problems occur.
In other words, in the image forming apparatus, the writing device and the developing device are arranged relatively close to each other because the visible image processing of the electrostatic latent image formed by writing the image on the photoreceptor and writing is continuously performed. Sometimes.
For this reason, if the air volume or air flow speed from the fan is increased, the toner that is only electrostatically attached to the recording paper may be blown off before fixing, which causes the toner scattered in the apparatus. May penetrate into the writing device. For this reason, the intruding toner adheres to the optical system component and is contaminated, so that an abnormal situation such as a part of the written image being lost may occur, and an image having a writing defect may be obtained.

  Therefore, in Patent Document 1, in order to solve the above-described problems, there is a configuration in which the number of fans is increased, a duct having a special structure is provided to form an exhaust passage, or a plurality of filters are provided. It is disclosed.

  However, in such a configuration, the duct used as a heat countermeasure for the optical system parts needs to be placed inside the optical writing device collectively, and the size is also large, and the airflow is obstructed. An arrangement that does not become necessary is required. As a result, an installation space for components in the apparatus is required, and there is a possibility that the apparatus will be enlarged due to an increase in the installation space in the apparatus.

  On the other hand, in Patent Document 4, a space for installing the heat insulating member and the air blowing means is required in a narrow space in the apparatus. It is necessary to set a considerable interval so as to obtain a state that is not affected by heat. For this reason, the problem regarding the installation space in an apparatus still remains.

On the other hand, when increasing the heat exhaust efficiency by increasing the number of air flow generation points in the device by increasing the number of fans to increase the exhaust heat efficiency, it is necessary to increase the cost of parts or increase the installation space. There is a possibility that not only will the apparatus be increased in size, but also the degree of generation of driving noise and airflow noise from the fan itself may be increased. In particular, when the electromagnetic induction heating method is used as the heat generation method of the fixing device, there is a risk that noise generation becomes significant due to the following reasons.
The magnetic force generating coil used for electromagnetic induction heating changes the insulation performance as the temperature rises, and may cause insulation failure depending on the temperature. For this reason, in order to prevent the temperature rise in a peripheral part and the overheating state of the coil for magnetic force generation, it is possible to perform heat dissipation by the air current as disclosed in the patent document.

However, when airflow is used, the flow rate may be increased in accordance with the size of the heat dissipation range. However, since the amount of heat generated with respect to the current flowing through the magnetic force generating coil changes depending on the square of the current, In order to obtain a calorific value for shortening the rise, it is necessary to pass a corresponding current, and accordingly, the flow rate of the cooling airflow for suppressing the influence of heat on the peripheral part must be increased. As a result, when the flow rate of the cooling airflow is increased, the airflow noise and the fan driving noise tend to increase, which may cause a new environmental noise problem. In particular, the inside of a metallic housing with a coil for generating magnetic force may have a small airflow passage space because many parts including not only the coil but also structural parts such as ferrite are arranged at high density. For this reason as well, there is a possibility that noise generation becomes significant by securing the flow rate of the cooling airflow and increasing the flow velocity for securing this flow rate.
However, recent image forming apparatuses tend to be miniaturized. For this reason, the mounting density of devices and apparatuses inside is increasing, and in the case of performing forced exhaust heat using a fan, patent literature However, the air flow in the apparatus becomes a problem as disclosed. That is, there are cases where an air flow for efficient exhaust heat is not generated simply by installing a suction fan on the apparatus wall. For this reason, there is a problem that heat is trapped in the apparatus or ozone cannot be discharged well.

  In view of the problem of the heat exhaust structure in the conventional image forming apparatus, an object of the present invention is an image forming apparatus having a configuration capable of preventing adverse effects due to hot air accumulated in the apparatus while preventing the apparatus from becoming large. It is to provide.

  According to the first aspect of the present invention, after an image obtained by performing visible image processing on an electrostatic latent image formed by image writing on a latent image carrier is transferred to a recording medium, the image on the recording medium is transferred. In an image forming apparatus capable of executing a method of obtaining a copy by heating and fixing, an image writing unit for the latent image carrier and a visible image processing unit of the latent image carrier and an electrostatic latent image formed thereon Provided in each of the writing unit and the image forming unit, a writing light exit opening is provided at a position facing the image forming unit in the writing unit, and outside air is taken into the writing unit at a position different from this. The first forced air intake means is provided, and air inside the apparatus is discharged outside the first forced air intake means to the apparatus casing near the fixing device that heats and fixes the recording medium. Forced exhaust means is provided, and in the middle of the movement direction of the air in the apparatus moving between the first forced intake means and the forced intake means, the air moving in the apparatus is brought into the heating source of the fixing device. A second forced intake means that can be taken in is provided, and the writing unit, the image forming unit, and the fixing device are arranged from the upstream side to the downstream side in the movement direction of the outside air taken in by the first forced suction means. The air moving from the writing unit crosses the image forming unit by being discharged through the writing light exit opening, and the air moving in the vicinity of the writing unit is the second air. It moves to the forced intake means.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the relationship between the total intake amount (Qin) by the first forced intake unit and the total exhaust amount (Qout) by the forced exhaust unit is Qin> It is characterized by being set to Qout.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the first forced air intake means is disposed at both ends in a direction perpendicular to the moving direction of the air taken in by the first forced intake means. It is a feature.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, a sirocco fan is used as the second forced air intake means.

  According to a fifth aspect of the present invention, in the image forming apparatus according to one of the first to third aspects, an axial flow fan is used as the first forced air intake means.

  According to a sixth aspect of the present invention, in the image forming apparatus of the first or fourth aspect, the total intake amount (Qin) by the first forced intake means, the total exhaust amount (Qout) by the forced exhaust means, and the second The relationship with the intake amount (Qmid) by the forced intake means is set such that Qin> Qout + Qmid.

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the writing unit in which the first forced air intake means is disposed corresponds to a plurality of color images. An image forming unit having a structure capable of forming an electrostatic latent image and having a latent image carrier on which the electrostatic latent image is formed has a structure capable of forming images of a plurality of colors.

According to the first aspect of the present invention, the writing unit, the image forming unit, and the fixing device are arranged from the upstream side to the downstream side in the movement direction of the outside air taken in by the first forced intake means provided in the writing unit. Therefore, it is possible to forcibly move the outside air taken in without using a special structure. In particular, since the air moving in the apparatus reaches the fixing device on the most downstream side in the moving direction, the components and toners installed in the writing unit and the image forming unit, which are the moving positions before that, On the other hand, it is possible to prevent a thermal adverse effect from the fixing device.
Moreover, since the air moving from the writing unit traverses the image forming unit through the writing light exit opening, it is possible to prevent toner from entering the writing unit from the image forming unit side, It becomes possible to reliably prevent a writing failure due to contamination of the optical component.

  According to the second aspect of the present invention, since the flow rate of the air taken into the apparatus from the writing unit side is set to be larger than the exhausted flow rate, the moving position of the air is made positive pressure. . This prevents outside air from entering from places other than the writing unit and prevents the movement of the air taken in, thereby promoting rectification of the air and preventing a decrease in heat dissipation efficiency due to the retention of air. Is possible.

  According to the third aspect of the present invention, since the first forced air intake means is disposed at both ends in the direction perpendicular to the air moving direction, the air can be eliminated and the air can be evenly moved throughout the apparatus. It is possible to improve the heat dissipation efficiency by the air flow by prompting and preventing stagnation.

  According to the fourth aspect of the present invention, the cooling efficiency for the fixing device is suppressed by suppressing the decrease in the moving speed when the air taken into the apparatus is sucked by using the centrifugal force generated in the sirocco fan. It is possible to prevent a decrease in the above.

  According to the fifth aspect of the present invention, it is possible to save space and move air efficiently by using the axial fan.

  According to the sixth aspect of the invention, similarly to the second aspect of the invention, it is possible to prevent the outside air from inadvertently entering from a place other than the writing unit due to the positive pressure in the apparatus by taking in air. As a result, the air moving through the apparatus can be rectified to prevent the air from staying, thereby preventing a reduction in heat dissipation efficiency.

  According to the seventh aspect of the present invention, even when the writing unit and the image forming unit use a configuration capable of forming an image of a plurality of colors, the air can be moved over the entire image forming portion of each color. As a result, it is possible to prevent overheating due to contamination of the optical components and heat retention associated with image formation for each color.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  FIG. 1 is an external view of an image forming apparatus 1 in which an exhaust heat structure according to an embodiment of the present invention is used. The image forming apparatus 1 shown in FIG. 2 is along the direction in which the transfer belt is extended as indicated by reference numeral 8A in FIG. Although it is a color printer (hereinafter referred to as color printer 1) having an image forming processing unit provided with juxtaposed image forming units 2Y, 2M, 2C, and 2B, the present invention is not limited to a color printer, but color copying. Machine, facsimile machine, printing machine, etc. are also included.

  The color printer 1 includes a document scanning device 20 at the top of the casing and a plurality of paper feed trays 21A, 21B across the image forming processing unit in which the image forming units 2Y, 2M, 2C, and 2B are juxtaposed. Each of the paper feeders 21 is provided. The upper surface of the housing below the document scanning device 20 is provided with a paper discharge tray 1A forming an in-body paper discharge unit, thereby eliminating the need for paper discharge space outside the device. An operation panel 20 </ b> A is provided on the front surface of the document scanning device 20.

  Covers 22 and 23 that can be opened and closed are provided on the side surface of the apparatus casing on the upper portion of the paper feed cassette 21A and on the wall surface in a direction perpendicular to the position, respectively, and image forming units 2Y and 2M that form an image forming processing section described later. 2C and 2B can be opened for replacement and maintenance.

  FIG. 2 is a diagram showing the configuration of the image forming processing unit. In FIG. 2, the document scanning device 20 located at the upper portion and the paper feeding device 21 located at the lower portion are omitted.

  In FIG. 2, an exposure unit 3 as a writing unit is disposed below the image forming units 2Y, 2M, 2C, and 2B that form an image forming processing unit.

Each of the image forming units 2Y, 2M, 2C, and 2B has the same configuration. Now, the configuration of a unit that forms a yellow image will be described as follows.
The image forming unit 2Y includes a photosensitive drum 4Y that can rotate as a latent image carrier, and an image forming process is executed around the photosensitive drum 4Y along the clockwise rotation direction in FIG. A charging device 5Y, an incident portion 6Y for writing light from the exposure unit 3, a developing device 7Y, a transfer device 8, and a cleaning device 9Y are arranged.

  In FIG. 2, the developing device 7Y uses a two-component developer containing toner and a carrier, and discharges the old developer by supplying the carrier in addition to supplying the toner for correcting the concentration of the developer. A trickle development system in which the developer can be replaced is adopted.

  In FIG. 2, the transfer device 8 includes a transfer belt 8A that can move while facing and facing the photosensitive drum of each image forming unit, and is positioned at a position facing the photosensitive drum 4Y across the transfer belt 8A. A transfer roller 8Y capable of applying a transfer bias is provided.

  The transfer device 8 in this embodiment includes a primary transfer process in which the visible images carried on the photosensitive drums in the image forming units 2Y, 2M, 2C, and 2B are sequentially transferred to the transfer belt 8A, and the primary transfer. A secondary transfer process is performed in which the image carried on the transfer belt 8A is transferred collectively to the recording paper fed from the paper feeding device 10 by the execution of the process. For this reason, a secondary transfer device 11 including a transfer roller to which a transfer bias can be applied is disposed at a position where the secondary transfer process can be performed.

The paper feeding device 10 is provided with a paper feeding cassette 10A for storing recording paper and a registration roller 10B arranged in the feeding path. The registration roller 10B is introduced from a manual paper feeding tray 10C. The recording paper conveyance path is provided at a position where it merges with the conveyance path from the paper feed cassette 10A.
In FIG. 2, reference numeral 12 denotes a cleaning device for the transfer belt 10A, and reference numeral 13 denotes a static eliminating device for the transfer belt 10A.

In the image forming processing section shown in FIG. 2, the color images respectively formed in the image forming units 2Y, 2M, 2C, and 2B are sequentially superimposed and transferred onto the transfer belt 8A of the transfer device 8 by the primary transfer process. . The images that are collectively transferred onto the recording paper in the secondary transfer process are fixed by a fixing device 14 that will be described in detail later.
As shown in FIGS. 1 and 2, the recording paper on which the image is fixed is discharged onto a paper discharge tray 1 </ b> A that is provided inside the apparatus and forms a cylinder discharge portion.

In the interior of the color printer 1, in the upper space of the image forming units 2Y, 2M, 2C, and 2B, the toner replenishing portions 15Y, 15M, 15C, and 15B used in the trickle developing method and the respective toner replenishing portions are shared. A carrier replenishing unit 16 is disposed.
In FIG. 2, the fixing device 14 includes rollers 14B and 14C arranged along the circumferential direction of the pressure roller 14A, and a heating roller provided at a position facing the pressure roller 14A across the rollers 14B and 14C. A fixing belt 14E wound around 14D is provided, and the fixing belt 14E is heated by an electromagnetic induction heating device 100 as an external heating source disposed in the vicinity of the surface.
3A and 3B are diagrams showing the configuration of the electromagnetic induction heating device 100. FIG. 3A is an external view, and FIG. 3B is an external panel in FIG. 3A (a member denoted by reference numeral 101B in FIG. 3A). The state where the inside is exposed is shown.
In the figure, an electromagnetic induction heating device 100 has a space for arranging a magnetic force generating coil 101A therein, and a heat source in which a part of the outer shell can surround the heating roller 14D (see FIG. 2). The magnetic force generating coil 101A is extended in a direction parallel to the width direction of the recording paper passing through the fixing device 14, and a plurality of locations are provided in the heat source housing 101 along the extending direction. It is supported.

  The heat source housing 101 is an airflow passage space in which the space between the heat source housing 101 and the exterior panel 101B (see FIG. 3A) extends in the extending direction except for the support position of the magnetic force generating coil 101A in the internal space. 3B, outside air is introduced from one end in the extending direction and can be discharged from the other end in the extending direction, as indicated by an alternate long and short dash line in FIG.

  One end of the heat source housing 101 in the extending direction is an outside air introduction side, and as shown in FIG. 4, a sirocco fan 102 that can introduce the outside air into a positive pressure is connected to this end. A chimney-like duct 103 is connected to the other end in the extending direction.

As will be described later, the sirocco fan 102 is an axial flow fan (members denoted by reference numerals 110 and 111 in FIG. 5) used as the first forced intake means and the forced exhaust means provided on the exposure unit 3 and the housing wall. In contrast, this is an advantageous member in that a relatively desired flow rate can be secured even in a small size. In this embodiment, the flow rate (Q of the sirocco fan 102 depends on the size of the recording paper to be fixed. ) as ^the relationship between 0.03m ³ /min<Q<0.15m 3 / min it is set.
The color printer 1 having such a configuration is provided with a configuration for forcibly discharging superheated air that tends to stay inside to the outside. This configuration will be described below.

  In FIG. 5, the members used for forcibly discharging the superheated air are provided in the axial fan 110 as the first forced air intake means provided in the exposure unit 3 and the printer casing in the vicinity of the fixing device 14. The axial flow fan 111 used as the forced exhaust means and the sirocco fan 102 provided as the second forced intake means provided in the electromagnetic induction heating source 100 provided in the fixing device 14 are applicable. In FIG. 5, the image forming units 2Y, 2M, 2C and 2B shown in FIG. 2 are omitted for convenience.

In the present embodiment, not only a forced airflow is generated using each of the above-described fans, but also a device for effectively moving the airflow in the housing is devised. That is, the outside air taken in by the axial fan 110 serving as the first forced intake means does not move according to the pressure difference in the housing or the applied speed, but by taking the movement process into consideration, the exposure unit 3 is prevented from adversely affecting the other units due to the prevention of toner from entering 3 and the heat from the fixing device 14.
That is, the exposure unit 3 is formed with an emission opening 3A for emitting writing light toward the photosensitive drum on the upper surface of the unit case facing the bottom surface of the image forming units 2Y, 2M, 2C, 2B. The exit opening 3A is used as a discharge unit for the outside air taken into the housing of the image forming apparatus.
Furthermore, as shown in FIGS. 2 and 5, the axial fan 110 provided in the exposure unit 3 as the first forced intake means is in the longitudinal direction of the exposure unit 3, that is, the image forming units 2Y, 2M, 2C. , 2B on the one side of the juxtaposed direction and away from the fixing device 14, the units are arranged side by side, in other words, on both sides of the direction perpendicular to the direction of air movement from the axial fan 110, respectively. Has been placed.

FIGS. 6A and 6B are diagrams for explaining the reason why the axial fan 110 is provided on both sides. FIG. 6A shows the case of the both-side arrangement in this embodiment, and FIG. 6B shows the arrangement on only one side. Each case is shown.
In FIG. 6, the black-painted portion indicates a portion where the flow velocity is 0.5 m / s or more. As is clear from this drawing, in the case of the both-side arrangement in this embodiment, the outside air taken in is shown. Can be moved in a substantially uniform distribution state from the upstream side to the downstream side in the moving direction. On the other hand, in the case where the arrangement is only on one side as shown in (B), the uniform velocity distribution state is biased near the discharge portion of the axial fan 110, in other words, only on the upstream side in the movement direction of the outside air. Therefore, it is difficult to obtain a uniform state from the upstream side to the downstream side in the moving direction.

  On the other hand, in FIG. 5, the axial flow fan 111 which is a forced exhaust means is a support position of the electromagnetic induction heating source 100 in the housing wall plate 1 </ b> A supporting the electromagnetic induction heating device 100 provided in the fixing device 14. It is provided inside an exhaust duct 1B connected to an air intake opening 1A1 formed above the air intake. Thereby, the air in the apparatus taken into the exhaust duct 1B from the air intake opening 1A1 is discharged to the outside of the housing. In FIG. 1, for convenience, reference numeral 1 </ b> B is attached to indicate the position of the duct.

In this embodiment, the relationship between the total intake amount (Qin) by the axial fan 110 as the first forced intake means and the total exhaust amount (Qout) by the axial fan 111 as the second forced intake means is Qin> The Qout relationship is set.
As a result, the inside of the housing is made positive by the intake of the outside air from the axial fan 110 used as the first forced air intake means, and the outside air enters from the places other than the exposure unit 3 in the housing. It can be blocked. As a result, the movement of the outside air taken into the exposure unit 3 by the axial fan 110 is rectified and can be moved toward the axial fan 111 as the second forced exhaust means. Due to such a relationship, turbulent flow does not occur in the air moving in the housing, so that the air does not stagnate in a part of the housing and the heat radiation efficiency can be prevented from being lowered.

Further, the total intake amount (Qin) of the axial flow fan 110 as the first forced intake means is equal to the intake amount (Qmid) of the sirocco fan 102 as the second forced intake means and the axial flow fan 111 as the forced exhaust means. As a relationship with the total exhaust amount (Qout), a relationship of Qin> Qout + Qmid is set.
As a result, the air taken into the housing is positively pressured, and outside air inadvertently enters from a location other than the taking-in position, for example, a gap formed on a joint surface of a cover used to close the housing. It is possible to rectify the air that moves in the housing.

  Since the present embodiment is configured as described above, only the exposure unit 3 is set as the outside air taking-in position into the housing, and the exposure units 3 and 3 move from the upstream side to the downstream side in the moving direction of the air moving in the housing. The image forming unit and the fixing device 14 are arranged in this order.

  In FIG. 5, the outside air F <b> 0 taken in by the axial flow fan 110 which is the first forced intake means provided in the exposure unit 3 is discharged from the exit opening 3 </ b> A formed in the exposure unit 3, thereby causing the image forming unit 2. The inside of the housing is crossed along the juxtaposed direction. That is, the air moving in the housing is discharged from the exit opening 3A of the exposure unit 3 (reference F1), and the air moves to the bottom surface of the image forming unit 2 and to the side thereof. In this case, since the total amount of intake air of the axial fan 110, which is the first forced air intake means, is larger than the flow rate of the other fans in the housing, the pressure is positive, so that the image forming units are arranged in the juxtaposition direction. Sufficient pressure will be maintained to traverse along and move toward the sides of the imaging unit.

  The air (reference numeral F2) moved to the side of the image forming unit can flow into the sirocco fan 102 as the second forced air intake means when flowing sideways from the housing side wall 1C. The air taken into the sirocco fan 102 moves in the electromagnetic induction heating device 100 (reference F2A), and the superheated air inside the heating source is discharged to the outside from the exhaust duct 103 (reference F2B).

  On the other hand, the air that has moved along the juxtaposition direction of the image forming units 2Y, 2M, 2C, and 2B moves in the upward direction by colliding with a wall surface in the housing or by generating an upward airflow due to the atmospheric temperature of the fixing device 14 ( Reference sign F3) is taken into the air intake opening 1A1 of the wall plate 1A and discharged outside (reference signs F4 and F5) by the axial fan 111 which is a forced exhaust means in the duct 1B.

  In the present embodiment having such a configuration, since the heat source approaches the heat source as it moves from the upstream side to the downstream side in the moving direction of the air, the hot air from the fixing device 14 that is the heat source toward the image forming unit or the exposure unit. Propagation will be prevented by the movement of air. In particular, the air flowing from the upstream side in the moving direction is lifted in the vicinity of the fixing device 14 and is forcibly moved and discharged to the outside by the suction action of the axial fan 111 as the forced exhaust means. There is no stagnation in the vicinity. Accordingly, it is possible to prevent the atmospheric temperature around the fixing device, which is caused by the staying air from being overheated, from rising abnormally.

  Further, the air taken into the housing from the outside is discharged toward the lower surface of the image forming unit through the emission opening 3A of the exposure unit 3, and moves so as to cross along the juxtaposing direction of the image forming units. Intrusion of toner into the exposure unit is prevented, and contamination of optical system components in the exposure unit 3 is prevented. As a result, it is possible to prevent the writing image from being lost due to the contamination of the optical system parts, thereby preventing the occurrence of a defective image.

  Further, since the outside air intake portion is only the exposure unit 3, unlike the case where an opening portion is provided as an outside air intake portion corresponding to a place where cooling is required, the generation of intake noise can be suppressed, and the environment can be suppressed. Noise can be reduced.

1 is an external view showing an example of an image forming apparatus equipped with a fixing device adopting a heat exhaust structure according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining a configuration of an image formation processing unit in the image forming apparatus shown in FIG. 1. 2A and 2B are diagrams for explaining a configuration of a part of an electromagnetic induction heating device used for a fixing device in the image forming apparatus shown in FIG. 1, in which FIG. The state where the inside is exposed is shown. It is an external view which shows the structure of the housing for heat sources of the electromagnetic induction heating apparatus which is the characteristic part in a present Example. It is a schematic perspective view for demonstrating the exhaust heat structure used for the image forming apparatus by a present Example. FIGS. 6A and 6B are diagrams for explaining the flow of air in the exhaust heat structure shown in FIG. 5, in which FIG. 5A shows the case of the first forced intake means in this embodiment, and FIG. Each case is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 1A, 1C Support wall board 1B Duct 2Y, 2M, 2C, 2B Image forming unit 3 Exposure unit 14 Fixing apparatus 14A Pressure roller 14B, 14C Roller 14D Heating roller 14E Fixing belt 100 Electromagnetic induction heating apparatus 101 For heat source Housing 102 Sirocco fan as second forced intake means 103 Exhaust duct 110 Axial fan as first forced intake means 111 Axial fan as forced exhaust means

Claims (7)

After an image obtained by performing visible image processing on the electrostatic latent image formed by image writing on the latent image carrier is transferred to a recording medium, the image on the recording medium is heat-fixed to obtain a copy. In an image forming apparatus capable of executing the method,
The image writing unit for the latent image carrier and the visible image processing unit of the latent image carrier and the electrostatic latent image formed thereon are provided in the writing unit and the image forming unit, respectively.
A writing light exit opening is provided at a position facing the image forming unit in the writing unit, and a first forced intake means capable of taking outside air into the writing unit is provided at a position different from this. ,
In addition to the first forced intake means, a forced exhaust means for exhausting the air inside the apparatus to the outside is provided in the apparatus casing near the fixing apparatus that heat-fixes the recording medium.
In the middle of the movement direction of the air in the apparatus that moves between the first forced intake means and the forced intake means, the second forced intake that can take in the air moving in the apparatus into the heating source of the fixing device. Means are provided,
The writing unit, the image forming unit, and the fixing device are arranged from the upstream side to the downstream side in the moving direction of the outside air taken in by the first forced intake unit, and the air moving from the writing unit is: An image characterized by traversing the image forming unit by being discharged through the emission opening of the writing light and air moving in the vicinity of the writing unit moving toward the second forced air intake means. Forming equipment. The image forming apparatus according to claim 1.
An image forming apparatus, wherein a relationship between a total intake amount (Qin) by the first forced intake means and a total exhaust amount (Qout) by the forced exhaust means is set to Qin> Qout. The image forming apparatus according to claim 1 or 2,
The image forming apparatus according to claim 1, wherein the first forced air intake means is arranged at both ends in a direction perpendicular to the moving direction of the air taken in by the first forced air intake means. The image forming apparatus according to claim 1.
An image forming apparatus, wherein a sirocco fan is used as the second forced air intake means. The image forming apparatus according to any one of claims 1 to 3,
An image forming apparatus using an axial fan as the first forced intake means. The image forming apparatus according to claim 1 or 4,
The relationship among the total intake amount (Qin) by the first forced intake means, the total exhaust amount (Qout) by the forced exhaust means, and the intake amount (Qmid) by the second forced intake means is set to Qin> Qout + Qmid. An image forming apparatus. The image forming apparatus according to claim 1,
The writing unit in which the first forced air intake means is disposed is configured to be capable of forming an electrostatic latent image corresponding to a plurality of color images, and a latent image carrier on which the electrostatic latent image is formed. An image forming apparatus comprising: an image forming unit configured to form an image of a plurality of colors.

Images