JPH07295463A - Cooling apparatus - Google Patents

Abstract

PURPOSE:To provide an image forming apparatus in which the effect of a cooling fan is not degraded even having used for a long time by controlling an air current generating means to generate first or second air current responding to the temperature detected by a temperature detecting means. CONSTITUTION:When the mode is turned into a print mode based on an print instruction, a fan 18 as an air current generating means is actuated by signals relating to the feeding of paper as sheets such as pick-up signals, etc., for a paper feeding roller 9 and is controlled by a controlling means as to generate second air current which suck outside air to the inside of a main body I. When no print instruction is given, the main body 1 is shifted to a waiting state, that is the stand-by mode, and at that time, the fan 18 is so controlled as to generate first air current to discharge the air inside the main body I to the outside. In this way, the fan 18 is switched to air suction and air discharge state based on the print mode and stand-by mode, so that the temperature rise of the paper and the inside of the apparatus at the time of printing can be prevented efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a cooling fan such as a copying machine and a printer to which an electrophotographic method is applied.

[0002]

2. Description of the Related Art FIG. 11 is a vertical sectional view of a conventional image forming apparatus I. The photosensitive drum 1 rotates in the direction of the arrow, and its surface is charged to a uniform potential by the charging roller 2. The output light of the laser 3 is reflected by the polygon mirror 4 on the photosensitive drum 1.
Is scanned in the longitudinal direction, the output of the laser 3 is turned on / off to provide the exposure 5, and the portion exposed to the light is discharged to obtain an electrostatic latent image. Colored charged particles (hereinafter referred to as toner) 7 are applied to the electrostatic latent image by the developing device 6 to visualize it. Sheet-shaped sheets in the form of cassette sheets are stacked and held in the cassette 8. The sheets are taken out one by one by the paper feed roller 9, and the photosensitive drum is synchronized with the visible image on the photosensitive drum 1 by the register roller 10. 1 and the transfer roller 11 are inserted into the nip portion. The transfer roller 11 applies a charge having a polarity opposite to that of the toner 7 to the back surface of the paper sheet, and the toner 7 is electrostatically transferred to the paper sheet. The untransferred toner on the photosensitive drum 1 is wiped by the cleaner 12, and the photosensitive drum 1 is used in the next image forming process. The paper sheet on which the toner 7 has been transferred is inserted into a fixing nip formed by a fixing roller 13 having a heater 15 and a pressure roller 14, and is heated and pressed to permanently fix the toner 7 on the paper sheet and eject the paper. It is discharged onto the tray 16. In the figure, the solid line indicates the path of the paper sheet.

The heater 15 is kept in a constant temperature range by inputting an output of a surface temperature sensor (not shown) of the fixing roller 13 to a temperature controller (not shown) and turning on / off the power to the heater 15. However, the temperature range thereof needs to be as high as 130 ° C. to 200 ° C. according to the melting point of the toner 7, and the power consumption of the heater 15 is generally 300 W to 1500 W depending on the peripheral speed of the photosensitive drum 1. Is. The heat generated by the heater 15 is mainly used for fixing the toner 7. However, a part of the heat is increased by the fixing roller 13 and the pressure roller 14, and the temperature of the parts of the image forming apparatus I and the air (hereinafter referred to as “in-machine temperature rise”). ) Is invited. For example, the temperature of the cleaner 12, which is often placed near the fixing roller 13 in terms of arrangement, has a softening point of the toner 7 (about 50 to 60 ° C.).
If it exceeds the range, the toner clogging causes no waste toner to be collected in the cleaner 12, resulting in serious problems such as toner spilling in the machine and image stains. Therefore, it is general that a fan 18 is provided near the fixing roller 13 to discharge excess heat inside the machine to the outside of the machine. At this time, if relatively cool air outside the machine is taken in from the louver 19 to increase the cooling efficiency, or if the peripheral speed of the photosensitive drum 1 is relatively high,
As the electric power of the heater 15 also increases, the temperature rise inside the machine also increases. Therefore, the fan 17 is provided to take in the air outside the machine into the machine, and the air flow inside the machine is made to suppress the temperature rise of each component. It is designed for efficient cooling. FIG. 12 is a plan view of the image forming apparatus I showing the relationship between main components and airflow. In the case of the fan 17 that sucks in air outside the machine, dust inside the machine may contaminate parts inside the machine or cause functional deterioration. Therefore, the filter 20 is generally provided.

FIG. 13 is a vertical sectional view of the image forming apparatus I (hereinafter referred to as the main body) to which the automatic duplex unit II is attached. That is, the main body I itself functions as a single-sided printing device, but the automatic double-sided unit II
By combining the above, it is possible to automatically print on the back surface of the leaf-like body that has been printed on one side. The paper sheet exiting the fixing nip as one-sided print is guided to the automatic double-sided unit II by the flapper 21, the traveling direction is reversed by the reversing roller 22, and is re-fed to the main body I by the re-feeding roller 24 for single-sided printing. The double-sided print is completed through the same steps as the above. The flapper 21 is at the position of the broken line during single-sided printing or after the second side of double-sided printing is fixed, and guides the paper sheet to the paper discharge tray 16 through the path of the broken line. The path of the paper sheet in the automatic duplex unit II after fixing the print on the first side is shown by a solid line. The fan 23 is provided in the automatic double-sided unit II , and exhausts the paper sheet immediately after being discharged from the fixing nip and the gas such as steam generated from the paper sheet to the outside of the machine to form the paper sheet in the fixing process of the first side. It is prevented that the temperature rise inside the main body I due to the accumulated heat increases.

It should be noted that the second side is printed on the same side as the first side by a known method without switching the front and rear ends of the paper sheet in the automatic double-sided unit II without using the reversing roller 22. You can also print.

[0006]

However, in the above-mentioned conventional example, since the air flow direction of the cooling fan is fixed, such as the fan 17 is intake air, the fan 18 is exhaust air, and the fan 23 is exhaust air. It turned out that there were some drawbacks.

1. When paper sheets are continuously fed, the heater 15 is kept on and the temperature rise inside the machine increases, but the fan 18 exhausts air, so the cooling efficiency is poor, and especially the paper sheet after fixing can be sufficiently cooled. Since there is no such sheet, there is a problem that overlapping prints on the discharge tray 16 are glued with the toner 7 or the toner 7 falls off. This is 200-5
This is a remarkable phenomenon when loading a large number of 00 sheets.

2. In the case of the intake fan 17, the filter 19 is clogged during long-term use, and the intake amount decreases,
There is a problem that the motor of the fan 17 is overheated and cannot rotate.

3. When the automatic duplex unit II is additionally connected to the main body I, there are the following problems.

(1) Since both the fan 18 and the fan 23 have an air flow in the exhaust direction, the fixing roller 13
The air in the vicinity is not exhausted smoothly, the air flow becomes stagnant, and the temperature rise inside the machine rather increases.

(2) The water vapor generated from the paper sheet heated by the fixing roller 13 is guided to the reversing roller 22 by the air flow produced by the fan 23, and the reversing roller 22
Condensation on the portion, the paper sheet gets wet, and water droplets adhere to the photosensitive drum 1 at the time of transfer of the second surface, which disturbs the electrostatic latent image at the time of subsequent image formation and causes image deletion. This is a particularly noticeable phenomenon in the morning when the entire apparatus is familiar with the outside air.

(3) The automatic double-sided unit II closes the opening of the harbor 19 to lower the cooling efficiency of the fan 18, and particularly when the fan 23 is turned off during standby or single-sided printing. As a result, the temperature rise inside the machine of I increases, and the waste toner in the cleaner 12 solidifies.

An object of the first invention of the present application is to provide an image forming apparatus in which the effect of suppressing the temperature rise inside the machine by the cooling fan is dramatically improved and the effect of the cooling fan does not deteriorate even after long-term use. That is.

A second object of the present invention is to effectively prevent the temperature rise inside the main body I to which the automatic duplex unit II is added.

[0015]

In order to achieve the above object, the first invention according to the present application is characterized in that the air flow direction of the cooling fan is switched between exhaust and intake air according to the image forming process. . With such a configuration, the inside of the main body I can be effectively cooled and the filter 1
Prevents 9 clogging. Further, when the automatic double-sided unit II is added, the fan 18 and the fan 23 can cooperate to form a series of air flows, so that dew condensation does not occur and temperature rise can be prevented.

Further, the second invention according to the present application is to prevent the temperature rise inside the main body I by operating the fan 23 of the automatic double-sided unit II even at the time of double-sided printing.

[0017]

【Example】

(First Embodiment) FIG. 1 is a vertical sectional view of an image forming apparatus I according to a first embodiment of the present invention.
For convenience of explanation, only main members related to the gist of the present invention are shown, and other parts are omitted. When the image forming apparatus I receives a print command from an external host computer (not shown) and enters an operating state, that is, a print mode, a blower means (blower) as an air flow generating means or a fan 18 causes a pickup signal of the paper feed roller 9 to be picked up. Is actuated by a signal related to the feeding of the paper sheet as a sheet, and the outside air is exposed to the main body.
It is controlled by the control means to generate a second airflow that is drawn into I. In this way, while the paper sheet is being discharged to the discharge tray 16 along the path indicated by the solid line arrow, the fan 18 applies external air to cool the paper sheet immediately after it is heated by the fixing nip, and the sheet is discharged even during continuous printing. It is possible to prevent the peeling of the toner on the sheets stacked on the tray 16. When the paper sheet is between the fixing nip in the main body I and up to the discharge tray 16, the outside air does not go to the inside of the main body I , and after the paper sheet is cooled, is discharged from the louver 19 to the outside of the main body I. Exhausted.
Since the paper sheets are continuously conveyed during continuous printing, even if the outside air contains dust, it does not diffuse into the main body I.

When the print command from the host computer (not shown) is interrupted, the main body I shifts to the standby state, that is, the standby mode. At this time, the fan 18 generates the first air flow for discharging the air inside the main body I to the outside of the machine. Controlled to occur. Thus, the heat generated by the heater 15 during standby is also exhausted to the outside of the machine by utilizing natural convection. The standby mode occupies a relatively large proportion of the moving time of the main body I , but during this time, the fan 18 is performing the exhaust operation, and there is no concern that the inside of the machine is contaminated with dust contained in the outside air.

As described above, by switching the fan 18 to intake / exhaust according to the print mode / standby mode, it is possible to efficiently prevent the temperature of the paper sheet and the temperature inside the machine during printing from increasing, and the main body I becomes dirty with dust. It is possible to prevent functional deterioration. The intake / exhaust of the fan 18 can be switched by a known method such as switching the polarity of the applied voltage so as to reverse the rotation direction of the fan using an axial fan. Further, the airflow amount during intake and exhaust or the rotation speed of the fan may be optimized according to the purpose. For example, the fan rotation speed during exhaust (standby mode) is half that of intake (print mode). It is also possible to prevent extra noise by, for example,

FIG. 2 shows an example in which the purpose of the present embodiment is applied to an automatic double-sided unit II as a casing having a feeding means for sending an image-formed sheet again to the image forming means. Automatic double-sided print mode is entered, and the paper sheet is automatically double-sided.
When the conveyance path II is used, the fan 23 is used for intake so as to apply the outside air to the paper sheet, and the paper sheet is efficiently cooled. On the other hand, in the modes other than the automatic double-sided print mode in which the conveyance path of the automatic double-sided unit II is not used, that is, the single-sided print mode or the standby mode, the fan 2 is used.
No. 3 is used for exhaust and does not blow dust from the outside air into the main body I.

(Second Embodiment) When the cooling fan is used by switching between intake and exhaust, the following effects are obtained in addition to the effects described in the first embodiment.

FIG. 3 shows a fan 1 having a filter 20.
7 is a cross-sectional view of a main part of the image forming apparatus I for switching the intake / exhaust operations of No. 7 between (a) print mode and (b) standby mode. The dust in the outside air is captured by the filter 20 in the print mode (a), but in the standby mode (b), clean air inside the machine forms an air flow in the opposite direction to that in the print mode (a). (A) The dust accumulated in the filter 19 in the print mode is blown out of the machine and the filter 19 is cleaned. Originally, (a) the print mode occupies a small proportion, so that the filter 20 is less contaminated, but (b) exhausting in the standby mode can further extend the life of the filter 20. By controlling the fan 17 to (a) print mode intake and (b) standby mode exhaust, dust in the outside air does not enter into the main body I itself, so that a low speed machine (heater) that requires a small amount of airflow. 15 has a relatively small power consumption of 200 W to 500 W, etc.), the filter 20 is unnecessary, but in a high-speed machine requiring a large amount of airflow (the power consumption of the heater 15 is relatively large, such as 600 W to 1500 W),
A filter 20 is preferably provided.

FIG. 4 shows the airflow in the vicinity of the operator A in (a) print mode and (b) standby mode when the fan 17 is provided at the position of the operation portion of the image forming apparatus I. Generally, in the print mode (a) in which the operator A is in the vicinity of the operation unit, by making the fan 17 perform an intake operation, the wind of the fan 17 is not blown to the operator A, and a comfortable operation environment can be provided. . On the other hand, in the standby mode (b), the operator A does not exist near the operation section, and the fan 17 can be exhausted without causing any harm. Switching between intake and exhaust of fan 17
Depending on the arrangement of the fan 17, the operation environment can be made friendly to the operator A in this way.

(Third Embodiment) FIG. 5 is a vertical sectional view of an image forming apparatus according to a third embodiment of the present invention, in which the main body I is shown in (a).
When used as a single-sided machine, the fan 18 is used for exhaust operation, but when (b) automatic double-sided unit II is added as a double-sided machine to perform double-sided printing, the fan 18 is switched to intake air and the fan 23 is exhausted. In conjunction with the operation, hot air does not stagnate in the vicinity of the fixing roller 15 and a series of air flows from the fan 18 to the fan 23 via the louver 19 'on the automatic duplex unit II side corresponding to the louver 19 on the main body I side. By forming the above, the outside air is efficiently cooled without being diffused into the main body I or the automatic double-sided unit II . Further, the actuating signal of the reversing roller 22 is used to switch the intake / exhaust directions of the fan 18 and the fan 23, and when the paper sheet exists in the main body I (b), the fan 18 is taken as the intake and the fan 23 is taken as the exhaust. If the paper sheet is present in the automatic duplex unit II (c), the fan 18 may be exhausted and the fan 23 may be sucked in to cool the paper sheet more efficiently. In any case, when the automatic double-sided unit II is added to the main body I , the fans 18 and 23 in the respective devices are made to cooperate with each other so that the air that enters from one fan does not go into the other so that the stagnation of the air flow does not occur. By forming the airflow so that it exits from the fan, it is possible to effectively prevent the temperature rise inside the machine.

(Fourth Embodiment) FIGS. 6 to 7 are vertical sectional views of an image forming apparatus according to a fourth embodiment of the present invention.
When (a) the in-machine temperature T of the main body I is equal to or lower than the predetermined temperature To, the fan 18 is exhausted during double-sided printing, and the fan 2
3 is stopped, and (b) when the in-machine temperature T exceeds To, the fan 18 is sucked in and the fan 23 is discharged in double-sided printing. The temperature T in the machine is detected by disposing a temperature detector (not shown) such as a thermistor near the fixing roller 13 to the fan 18. That is, since the automatic duplex unit II is farther from the main body I than the heater 15 that is a heat source, the temperature rise inside the machine is relatively small, and when performing double-sided printing from a state where the apparatus as a whole is accustomed to the outside air temperature, a fan is used. 90g when exhausted when 23 is activated
When a thick paper sheet having a thickness of r / m ² or more is used, the vapor after fixing the paper sheet may be drawn into the automatic double-sided unit II and be condensed on the reversing roller 22 to cause image deletion, Further, if the air is taken in, the cold outside air is sent to the vicinity of the fixing roller 13 to lower the fixing property, and the heater 1
This causes a problem that 5 consumes extra power. Therefore, the in-machine temperature T in the main body I is the predetermined value To (for example, 30
When the temperature is lower than or equal to (° C.), the fan 32 should be turned off. On the other hand, when the internal temperature T exceeds To, the automatic duplex unit I
I has also obtained a suitable temperature rise in the machine, and since the reversing roller 22 is also sufficiently high in temperature, no condensation occurs, so the fan 2
3 is an exhaust gas, and the fan 18 is an intake air to create a series of air flows to suppress the temperature rise inside the main body I.

In FIG. 7, the time t at the start of double-sided printing is measured by a time measuring means such as a timer, and a predetermined elapsed time t after the surface temperature of the fixing roller 15 reaches the fixable temperature.
Compared to o, when (a) t ≦ to, the fan 18 is exhausted, the fan 23 is intake air, and (b) to <t, the fan 18 is intake air and the fan 23 is exhausted air. It is controlled by the control means. That is, when the surface temperature of the fixing roller 15 reaches the fixing possible temperature, to (mi
During n), the temperature rise in the machine is small, so automatic duplex unit
An air flow that does not guide the water vapor of the paper sheet to the II side is created, and there is no risk of dew condensation on the reversing roller 22 after the increase in the machine temperature to (min). Therefore, the air flow is switched to increase the machine temperature increase. The purpose of this embodiment is to positively suppress it. When (a) t ≦ to and a thick paper sheet is used, in order to secure the fixing property,
When the fan 23 is turned off, the efficiency of the heater 13 is better, but in the case of a thin letter of less than 90 gr / m ² , the fixing property is originally good, and the purpose is to prevent the deformation of the paper sheet such as curl. Thus, the fan 23 can be used as an intake air, and a series of air flows can be created in cooperation with the fan 18 to effectively cool the paper sheet. As described above, by monitoring the temperature control time t of the fixing roller 13, the temperature detecting element can be omitted as compared with the case where the temperature T is monitored, and the timer originally provided for sequence control is used. Can control at lower cost.

(Fifth Embodiment) FIGS. 8 and 9 are longitudinal sectional views of an essential part of an image forming apparatus according to a second embodiment of the present invention. Indicates.

FIG. 8 shows the operating state of the fan during single-sided printing when the automatic double-sided unit II is additionally installed in the main body I. At this time, the paper sheet does not enter the automatic double-sided unit II and the paper is conveyed. Although the function does not operate at all, the fan 23 operates to suppress the temperature rise inside the main body I during single-sided printing. In this way, it is possible to compensate for the decrease in the cooling effect of the fan 18 due to the blockage of the louver 19, prevent the waste toner from sticking to the cleaner 12 and prevent toner spillage, and obtain a clean print output. Figure 9 is intended to also showing the operating condition of the fan in the standby mode, the automatic duplex unit II of the fan 23 Again to prevent temperature rise in the apparatus main body I, the cooling effect in cooperation with the fan 18 of the body I Demonstrate. The exhaust of the fan 23 /
The intake air volume is made smaller than the value for double-sided printing, and
As shown in FIG. 1, it is preferable that the number of revolutions be controlled so as to minimize the noise accompanying the rotation of the fan, such as 0.5 times for single-sided printing and 0.2 times for standby. The gist of the present invention is that the effect of suppressing the in-machine temperature rise of the main body I , which is impaired by the addition of the automatic duplex unit II, is achieved in print modes other than the automatic duplex print mode.
It is obvious that the automatic double-sided unit II compensates by the fan 23, and can be applied, for example, even when the fan 18 of the main body I is not provided, and the intake / exhaust of the fan 23 is set according to the conditions unique to the device. do it. The route of the automatic duplex unit II of the fan 23 inhales or exhaust air of flight of the body I is a body I along the path of the sheet material for automatic duplex printing out of the opening of the louver 19, 19 'automatically It goes without saying that there is also a paper sheet delivery port (not shown) of the duplex unit II .

[0029]

As described above, according to the present invention,
By switching the intake and exhaust of the cooling fan 18,
When the automatic double-sided unit II is added to the main body I by suppressing the temperature rise inside the machine, the paper sheet can be cooled effectively, and the clogging of the filter 20 can be prevented.
The fan 23 and the fan 23 cooperate to form a series of airflows, so that dew condensation on the reversing roller 22 does not occur, and the effective temperature rise in the machine can be suppressed. Further, by operating the fan 23 of the automatic double-sided unit II during standby or single-sided printing, clogging of the waste toner of the cleaner 12 can be prevented and a clean print can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an image forming apparatus main body I according to a first embodiment of the present invention, in which (a) printing is performed and (b) standby is performed.

FIG. 2 is a longitudinal sectional view of the main body I and the automatic duplex unit II according to the first embodiment of the present invention, in which (a) printing and (b) standby are performed.

FIG. 3 is a cross-sectional view of the main part of the main body I of the second embodiment of the present invention, showing (a) during printing and (b) during standby.

FIG. 4 is a sectional view of a main part of a main body I of a modified example of the second embodiment of the present invention, showing (a) printing and (b) standby.

FIG. 5 is a vertical sectional view of a main body I and an automatic double-sided unit II according to a third embodiment of the present invention, (a) single-sided printing, (b)
Modified examples of double-sided printing and (c) double-sided printing.

FIG. 6 is a vertical sectional view of a main body I and an automatic duplex unit II according to a fourth embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view of a main body I and an automatic duplex unit II according to a modified example of the fourth embodiment of the present invention.

FIG. 8 is a vertical sectional view of a main body I and an automatic duplex unit II according to a fifth embodiment of the present invention.

FIG. 9 is a vertical cross-sectional view of a main body I and an automatic duplex unit II according to a modified example of the fifth embodiment of the present invention.

FIG. 10 is a diagram showing a relationship between a device operation mode and a fan intake or exhaust amount according to a fifth embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view of a conventional image forming apparatus (main body) I.

FIG. 12 is a plan view of a conventional image forming apparatus (main body) I.

FIG. 13 is a vertical sectional view of a conventional image forming apparatus (main body) I and an automatic duplex unit II .

[Explanation of symbols]

1 Photosensitive Drum 6 Developing Device 7 Toner 8 Cassette 9 Paper Feed Roller 11 Transfer Roller 12 Cleaner 13 Fixing Roller 14 Pressure Roller 15 Heater 16 Paper Ejection Tray 17, 18, 23 Fan 19, 19 'Louver 20 Filter 21 Flapper 22 Reverse Roller 24 Refeed Roller I Main Body II Automatic Duplex Unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuko Ogama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yozo Horita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Satoru Izawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shoji Maruyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (16)

[Claims] 1. A first flow from inside the apparatus body to outside the apparatus body
Air flow generating means for selectively generating a second air flow flowing from the outside of the apparatus main body to the inside of the apparatus main body, a temperature detecting means for detecting the temperature inside the apparatus main body, and a temperature detecting means for detecting the temperature. A cooling means for controlling the air flow means so as to generate a first or a second air flow according to the temperature; 2. The air flow generation means for generating a first air flow when the temperature detected by the temperature detection means is below a predetermined value, and generating a second air flow when the temperature detected by the temperature detection means is above a predetermined value. The cooling device according to claim 1, wherein the cooling means controls the means. 3. The apparatus according to claim 1, further comprising a second airflow generating means for generating an airflow flowing from the inside of the device body to the outside of the device body when the temperature detected by the temperature detecting means is equal to or higher than a predetermined value. Cooling system. 4. The apparatus according to claim 3, wherein the second air flow generating means is provided in a housing mounted on the apparatus main body and generates an air flow flowing into the apparatus main body through the housing. Cooling system. 5. A first device that flows from inside the apparatus body to outside the apparatus body
And an air flow generating means for selectively generating a second air flow flowing from outside the device body into the device body, and a time measuring means for measuring an elapsed time after the operation switch of the device body is turned on. A cooling unit for controlling the airflow generating unit so as to generate the first or second airflow according to the time measured by the time measuring unit. 6. The air flow generation means for generating a first air flow when the time measured by the time measuring means is a predetermined value or less, and a second air flow when the time measured by the time measuring means is a predetermined value or more. 6. The cooling device according to claim 5, wherein the cooling means controls the means. 7. When the airflow generating means generates a first airflow, an airflow flowing from the outside of the apparatus body into the apparatus body is generated, and when a second airflow is generated, from inside the apparatus body to outside the apparatus body. The cooling device according to claim 5, further comprising a second air flow generating unit that generates an air flow flowing to the cooling device. 8. The apparatus according to claim 7, wherein the second air flow generating means is provided in a housing mounted on the apparatus main body and generates an air flow flowing into and out of the apparatus main body through the housing. Cooling system. A second airflow generating means for generating an airflow flowing from the inside of the apparatus main body to the outside of the apparatus main body at the time of the second airflow generating means is provided in a housing attached to the apparatus main body, and through the housing. The cooling device according to claim 3, wherein an air flow flowing into the device body is generated. 9. An image forming means for forming an image on a sheet, a first airflow flowing from inside the apparatus main body to the outside of the apparatus main body, and a second airflow flowing from the outside of the apparatus main body to the inside of the apparatus main body selectively. Airflow generating means for generating, temperature detecting means for detecting the temperature inside the apparatus main body, and controlling the airflow generating means so as to generate a first or second airflow according to the temperature detected by the temperature detecting means An image forming apparatus, comprising: 10. The image forming apparatus according to claim 9, wherein the image forming unit has a fixing unit that applies heat to the sheet to fix the image formed on the sheet. 11. An air flow generation means for selectively generating a first air flow flowing from the inside of the device main body to the outside of the device main body and a second air flow flowing from the outside of the device main body to the inside of the device main body, and the device main body is on standby. A cooling means for controlling the airflow generating means so as to generate a first airflow in the state and a second airflow in the operating state. 12. An image forming unit for forming an image on a sheet, a first airflow flowing from inside the apparatus body to the outside of the apparatus body, and a second airflow flowing from outside the apparatus body to the inside of the apparatus body selectively. An air flow generation means for generating the air flow, and a control means for controlling the air flow generation means so as to generate a first air flow when the apparatus main body is in a standby state and generate a second air flow when the apparatus main body is in an operating state. An image forming apparatus characterized by the above. 13. The image forming apparatus according to claim 12, wherein the image forming unit has a fixing unit that applies heat to the sheet to fix the image formed on the sheet. 14. The image forming apparatus according to claim 13, further comprising a unit that sends the sheet on which the image is formed by the image forming unit to the image forming unit again. 15. An image forming unit disposed inside the apparatus body to form an image on a sheet, a first airflow flowing from inside the apparatus body to the outside of the apparatus body, and a second airflow flowing from outside the apparatus body to inside the apparatus body. A first airflow generating means for selectively generating an airflow, and a housing that is mounted on the apparatus main body and has means for sending the sheet on which the image is formed by the image forming means to the image forming means again. Second airflow generating means for selectively generating a third airflow flowing from the body to the outside of the housing and a fourth airflow flowing from the outside of the housing to the inside of the housing; and when the seat is inside the apparatus main body, The first and second airflow generating means are controlled so that the second airflow and the third airflow are generated, and when the seat is in the housing, the first airflow and the fourth airflow are generated. And the first and second air flow generating means An image forming apparatus comprising: the Gosuru control means. 16. An image forming unit that is disposed in the apparatus main body and forms an image on a sheet; a first airflow generating unit that generates an airflow flowing from the inside of the apparatus main body to the outside of the apparatus main body; A casing having a feeding unit for sending the sheet on which the image is formed by the image forming unit to the image forming unit again; a second air flow generating unit for generating a flow from outside the casing body into the casing; And the airflow generated by the second airflow generating means is
In the standby state, the number of cases in which only the apparatus main body is operated is larger, and more cases in which both the apparatus main body and the feeding means are operated than in the case of operating only the apparatus main body. 2. An image forming apparatus, comprising: a control unit that controls the air flow generating unit.