JPH063917A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device excellent in cooling efficiency. CONSTITUTION:This device is provided with a control means 140 controlling the cooling operation time of a cooling means(fan) 111 after finishing image forming actuation in an image forming device main body so as to be in proportion to the number of times of image forming actuation. An air passage changing means 202 is provided near the aperture part of the device main body. Then, an air capacity changing means 319 changing the rate of the air capacity per unit time formed by 1st and 2nd air passage forming means 317 and 318 is provided. An outside air suction path 458 communicating between a 2nd temperature rise part 450 side and the outside of the device main body 401 is provided to introduce the outside air from the path 458 by an air blowing means, whereby the outside air is sent with gas near a 1st temperature rise part 451 to the 2nd temperature rise part 450.

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 such as an electrophotographic copying machine or a laser beam printer, and more particularly to a cooling technique for preventing a temperature rise inside the apparatus body.

[0002]

[Prior art]

[First Conventional Example] A conventional image forming apparatus of this type has a main body cooling fan 111 as a cooling unit as shown in, for example, FIG. 4 (a sectional view of the image forming apparatus).

The main body cooling fan 111 generates heat (for example, the fixing device 12) generated during image forming operation inside the main body of the apparatus.
6, heat generated from the light source lamp 127 and a motor for driving the main body of the apparatus (not shown) is released to the outside of the main body of the apparatus to prevent temperature rise inside the main body of the apparatus.

Further, the main body cooling fan 111 is "reverse rotation".
Is also going. “Post-rotation” is to rotate the main body cooling fan 111 for a certain period of time after the operation of the main body of the apparatus is completed. The following items are listed as the purpose of the post-rotation of the main body cooling fan 111.

It prevents the temperature rise inside the apparatus body when the apparatus body is stopped (during standby: power is on). This is because the fixing device 126 maintains a constant temperature in preparation for the next copy even during standby, so that air stagnates and the temperature easily rises.

Prevent overshoot. The overshoot is a phenomenon in which the temperature of the inside of the apparatus main body, the process cartridge 128 and the like slightly rises due to the stagnation of air immediately after the operation of the apparatus main body ends.

The temperature rise (overshoot) of the document glass 110 immediately after the copying operation of the apparatus main body is finished is prevented.

However, the post-rotation time of the conventional cooling fan is always constant regardless of the number of copies (the number of copies set by the operator of the apparatus before copying). [Second Conventional Example] Conventionally, as a cooling fan provided in an image forming apparatus, there is a main body cooling fan 201 or an optical cooling fan 205 as shown in FIG. 13, for example.

The body cooling fan 201 is provided inside the apparatus body 21.
By radiating the heat of No. 4 (for example, the heat generated by the fixing device 211, the main body driving motor (not shown), etc.) to the outside of the machine, the temperature rise inside the apparatus main body 214 is prevented. The arrow 204 in the figure indicates the flow of air discharged outside the machine by the main body cooling fan 201.

Next, the optical cooling fan 205 sucks the air outside the machine into the inside of the optical system 208 (the air flow is indicated by the arrow 20).
6) prevents the temperature rise inside the optical system 208 due to the heat generated by the light source lamp in the first mirror base 207. In addition, the main body cooling fan 201 and the optical cooling fan 20
5 both perform post-rotation (rotate the cooling fan for a certain period of time or at a low rotational speed after the end of the operation of the apparatus). The purpose of the post-rotation is as follows in the case of the main body cooling fan 201.

Prevent overshoot. Here, the overshoot is similar to the above-mentioned conventional technique,
This is a phenomenon in which the temperature of the inside 214 of the apparatus main body, the process cartridge 210, and the like slightly rises due to the stagnation of air immediately after the operation of the apparatus main body is completed.

The temperature rise inside the apparatus body 214 is prevented when the apparatus body 209 is stopped (standby). This is because the fixing device 211 maintains a constant temperature in preparation for the next copy even during standby, so that air stagnates and the temperature easily rises.

Similarly, the purpose of post-rotation in the case of the optical cooling fan 205 is as follows.

A first mirror base 20 holding a light source
By cooling 7 the phenomenon in which the temperature of the platen glass 215 directly above the optical system 207 rises when the overshoot device body is stopped is prevented. Particularly, in the case of an image forming apparatus of a fixed platen type, the first mirror stand 207
Since it also stops at a specific position, the temperature of the platen glass 215 directly above the first mirror table 207 is likely to rise.

The temperature rise of the platen glass 215 is prevented immediately after the image forming operation is completed. This is one of the safety measures for users.

[Third Conventional Example] FIG. 23 shows the configuration of a conventional image forming apparatus of this type. As shown in FIG.
Is an illumination lamp, which irradiates a document 303 placed on the document table glass 302 in the left-right direction in the drawing to perform optical scanning, and the reflected light is reflected on a photosensitive drum 305 via a mirror 304. It is exposed and a latent image is formed. Then, the latent image is visualized by the developing device 306. On the other hand, the recording sheets 307 are registered in the cassette 308 by the sheet feeding roller 309 or manually by the sheet feeding roller 311 through the manual sheet feeding port 310.
Sent to 12. Then, the recording sheet 307 is sent to the photosensitive drum 305 in synchronism with the above-described image position, an image is formed by the transfer charger 313, and then the image is fixed by the heat fixing device 315 via the conveyance belt 314. It is discharged to the outside of the machine.

The cooling system in the image forming apparatus is composed of fan devices 316 and 317. The fan device 316 discharges heat generated by the heat fixing device 315 and elements of a power circuit (not shown) to the outside of the machine. The temperature of each part of the developing device 306 and the like is prevented from rising excessively, and the fan device 317 takes in cool air from the outside of the device to prevent the original plate glass 30
Illumination lamp 301 by forming an air passage around 2
The temperature is prevented from rising excessively due to the irradiation, and the user is prevented from being burned when touching the glass.

[Fourth Conventional Example] FIG. 28 is a front sectional view of an electrostatic copying machine according to a fourth conventional example. In the figure, 40
Reference numeral 0 denotes an apparatus main body, and an original placing table 402 made of glass or the like is provided on the upper side of the apparatus main body 400, and the original a is placed on the original placing table 402 for use. This original a is scanned by the irradiation light of an illumination lamp 403 provided below the original table 402, and its reflected light is reflected by mirrors 404 to 409.
Are sequentially reflected by and are exposed on the photosensitive drum 410. The original placing table 402, the illumination lamp 403, the mirrors 404 to 407, etc. are the second temperature raising unit 4200.

The photosensitive drum 410, whose surface charge distribution has been flattened by the charging device 411 before the exposure, forms a latent image through the above-described exposure process and then develops the latent image by the developing device 4.
The toner in 12 forms a development.

On the other hand, in synchronization with the above operation, the paper feed cassette 4
The transfer papers 414 in the sheet 13 are fed one by one by a paper feed roller 415, and penetrate into a nip portion of a registration roller 417 via a guide member 416.

In addition to the above cassette sheet feeding, the present apparatus can also be manually fed one by one. In this case, the transfer paper 414 is manually inserted along the upper surface of the manual feed tray 418 up to the vicinity of the feed roller 419. At this time, the rotation of the feeding roller 419 is started as detected by the transfer sheet detecting means (not shown) near the feeding roller 419,
It is sent to the registration roller 417 as in the case of the cassette paper feeding.

As described above, the transfer paper 414 fed by the cassette 413 or the manual feed is the registration roller 41.
7, the photosensitive drum 410 is synchronized with the toner image.
And the toner image is transferred by the charger 420. Thereafter, the transfer paper 414 is sent to the fixing device 422 by the conveyor belt 421, the toner image is fixed on the transfer paper 414, and the transfer paper 414 is ejected onto the paper ejection tray 423. The fixing device 422 has a heating roller 422a and a pressure roller 422b. Further, the residual toner remaining on the photosensitive drum 410 after the transfer is
The cleaning device 424 scrapes off the photosensitive drum 410.

The fixing device 422 and the chargers 411 and 42
0 and the like are the first temperature raising unit 4202. A partition 4201 is provided between the first temperature raising unit 4202 and the second temperature raising unit 4200.
Is provided to prevent the disturbance of the image light formed in the second temperature raising section.

A blowing fan (blowing means) 425 is provided above the fixing device 422, and as shown by the arrow, the gas in the main body 400 of the apparatus, that is, the heat generated in the fixing device 422 and the chargers 411, 420. Inhale ozone generated in. Then, the ozone absorption filter (not shown) and the discharge port 4203 on the side surface of the apparatus main body 400 are discharged to the outside of the machine to prevent malfunctions and toner fusion due to excessive temperature rise, and also to prevent the ozone on the photosensitive drum 410. It prevents deterioration of the photosensitive layer.

Reference numeral 426 denotes a blower fan as a blower provided on the side of the second temperature raising unit 4200, which takes in outside air from the suction port 4204 of the main assembly 400 of the apparatus and mainly places the original table 40.
After being blown toward the lower surface of No. 2, the discharge port 4205 is again discharged to the outside of the machine to prevent the temperature of the document placing table 402 from being excessively raised by the illumination lamp 403.

FIG. 29 is a front sectional view showing an electrostatic copying machine according to another mode of the fourth conventional example. In this conventional example, an air passage 4206 that connects the first temperature raising unit 4202 side and the second temperature raising unit 4200 side is provided inside the apparatus main body 400, and the air passage 4206 serves as a single air blowing unit. Blower means 427 is provided. Other configurations are similar to those of the conventional example shown in FIG.

In the conventional example thus constructed, the air is blown from the first temperature raising section 4202 by the blower fan 427 to remove the heat of the first temperature raising section 4202 to cool it.
The gas is sent as it is to the second temperature raising unit 4200 via the air passage 4206 to cool the second temperature raising unit 4200.

[0028]

[Problems to be Solved by the Invention]

[First Problem] In the first conventional example, as described above, the post-rotation time of the body cooling fan 111 is constant regardless of the number of copies (for example, even if the number of copies is 1, 100).
Even if the number of sheets is the same, the post-rotation time is the same), so there were the following drawbacks.

Immediately after a large amount of continuous copying (for example, 100 sheets or more) is performed, the temperature of the platen glass 110 and the inside of the apparatus main body becomes very high. Therefore, the platen glass 10
There are drawbacks such that there is a risk of human being touching 0 and being burned, and toner (developer) is melted at a high temperature to deteriorate image quality.

Conversely, when the number of copies is small (for example, 1
(About 2 sheets), the temperature inside the platen glass 110 and the inside of the apparatus body hardly rises. However, since the main body cooling fan 111 rotates for a predetermined post-rotation time, waste of power consumption and unnecessary noise from the main body cooling fan 111 are maintained more than necessary (although the copying operation is completed, the main body cooling fan 111 does not operate). (111 is rotating more than necessary).

[Second Problem] In the second conventional example, since the main body cooling fan 201 and the optical cooling fan 205 are simultaneously used for the rearward rotation, there are the following drawbacks.

After the main body of the apparatus is stopped, the main body cooling fan 2
01 and the optical cooling fan 205 are simultaneously rotated backward, so that noise is large. Especially, since the device itself is stopped, fan 2
The wind noises of 01 and 205 are easy to hear.

Since the main body cooling fan 201 and the optical cooling fan 205 are rotated at the same time, power consumption is higher than that in the case where there is only one cooling fan.

Since the post-rotation amount has to be taken into consideration in the life time of the optical cooling fan 205, the optical cooling fan 205 having a higher cost, which is one rank higher, has to be adopted.

[Third Problem] In the third conventional example, the relationship between the temperature change and the elapsed time from the start of the operation of the upper surface of the original platen glass 302 and the periphery of the developing device 306, for example, is shown in FIG. The horizontal axis indicates time h, A indicates the upper surface of the platen glass, and B indicates the periphery of the developing device). The temperatures of both of them are rapidly increased in the initial stage, and then the gradient is gradually decreased to a certain temperature ( (x, y degrees), the temperature rise gradient of both is different, and the time until the temperature reaches the saturation is different from the saturation temperature. Generally, the temperature A of the platen glass 302 rises more rapidly and becomes saturated. It takes a short time to reach and the saturation temperature is high.

According to the experiments conducted by the present inventors, x is about 60 degrees C, y is about 35 to 40 degrees C, and the saturation time of x and y is about 1 hour and about 2 hours. The temperature of the upper surface of the glass and the temperature around the developing device, which are given as examples here, are extremely important factors in the performance of the image forming apparatus such as a copying machine.

That is, the upper surface of the original platen glass 302 is one of the portions that the user directly touches as described above, and it is, of course, necessary to keep the temperature sufficiently lower than the temperature at which the hand or finger is burned. In addition, since the toner contained inside the developing device is mainly made of resin as a raw material, there is a risk that the toner may be melted on the photosensitive drum 305 or the like due to high temperature and deteriorate the image. For cooling, sufficient cooling is required.

As described above, the platen glass 302
Although the temperature gradient between the top surface and the developing device is different, the fan device 31
7 around the platen glass 302, the fan unit 316
The respective units such as the developing device 306 are individually cooled by, and the first copy, the 100th copy, and the 1st copy
It is constant regardless of the number of copies, such as the 000th copy, and the cooling efficiency cannot be said to be effective.

Further, in a small-sized copying machine for personal use, it is rare that it is continuously used for 1 hour or 2 hours.
Since most of them are used before reaching the saturation temperature shown in FIG. 24, it is necessary to improve the cooling efficiency especially before such saturation temperature.

[Fourth Problem] In the fourth conventional example, since the blower fans 425 and 426 are provided separately corresponding to the first temperature raising section 4202 and the second temperature raising section 4200, respectively, the number of parts is reduced. The increase in manufacturing cost leads to an increase in the weight and size of the device.

Further, in the conventional example of FIG. 29, the blower fan 4
Since 27 alone cools both the first and second temperature raising parts 4202 and 4200, the above problem does not occur, but there is the following new problem.

The temperature of the gas sucked from the first temperature raising unit 4202 is higher than that of the outside air because it takes away its heat, and the second temperature raising unit 420 is higher than that of the conventional example shown in FIG.
The cooling efficiency at 0 decreases.

To eliminate the above, the blower fan 42
It is necessary to have a large capacity so that the blower fan 425, 426 alone or a blower fan having a blower amount of 7 or more.

However, in order to increase the air volume, the blower fan 427
It is necessary to change the shape of the blade and the shape of the casing, or to increase the number of revolutions, but at this time, noise such as wind noise and operating noise also increases. Therefore, it is not preferable to increase the air flow rate.

[Common Object of the Invention] The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object common to all the inventions is to provide an image forming apparatus excellent in cooling efficiency. It is in.

[Object of the First Invention] Particularly, the object of the first invention is to solve the problems of the first conventional example, and to control the cooling operation time of a cooling fan or the like after image formation to achieve cooling. To improve efficiency.

[Object of the Second Invention] The object of the second invention is to solve the problems of the second conventional example so that the main body of the apparatus is divided into upper and lower components and the inside of each component is cooled. In doing so, it is to efficiently cool with one cooling fan.

[Object of Third Invention] An object of the third invention is to solve the problems of the above-mentioned third conventional example to prevent the temperature rise of the first and second heat generating parts. The cooling efficiency is increased by controlling the ratio of the air volume of the air passage forming means.

[Object of Fourth Invention] An object of the fourth invention is to solve the problems of the above-mentioned fourth conventional example so that both the first and second temperature raising parts can be efficiently provided by a single blowing means. Moreover, it is to cool without increasing noise.

[0050]

[Means for Solving the Problems]

[First Invention] In order to achieve the above object, the first invention is
In an image forming apparatus in which the apparatus body is provided with a cooling means for cooling heat generated during the image forming operation, the cooling operation time after the image forming operation of the apparatus body of the cooling means is finished,
It is characterized in that a control means is provided so as to be controlled in proportion to the number of image forming operations.

The number of image forming operations is preferably counted according to the number of image-formed transfer materials on which an image is formed.

Further, it is preferable to provide a control circuit which charges the capacitor during the image forming operation and determines the operating time of the cooling means after the operation of the apparatus main body is in proportion to the discharge voltage of the capacitor after the image forming is completed. .

[Second Invention] A second invention comprises a cooling fan for cooling the upper structure of the apparatus main body and a cooling fan for cooling the lower structure of the apparatus main body, and comprises a cooling fan for the upper structure and the lower structure. An image forming apparatus having an opening at the boundary is characterized in that an air passage changing unit is provided near the opening.

It is preferable that, when the apparatus body is stopped, the air passage changing means is moved to a position where the air passage to the outside of the apparatus body is blocked.

[Third Invention] According to a third invention, a first heat generating portion having at least one illuminating means for irradiating an original placed on an original placing table to perform optical scanning, and optical scanning. A second heat generating portion having at least one fixing means for fixing the image information obtained by the method to the recording medium, and a first heat generating portion for forming an air passage around the first heat generating portion to prevent an excessive temperature rise. An image forming apparatus comprising: an air passage forming unit; and a second air passage forming unit that forms an air passage around the second heat generating portion to prevent an excessive rise in temperature, wherein the first and second air passages are provided. It is characterized in that an air volume changing means for changing the rate of each air volume formed by the forming means per unit time is provided.

It is preferable that the air flow rate changing means comprises a wind direction switching plate that changes a passage path of an air passage formed by at least one of the first and second air passage forming means. Is.

The wind direction switching plate is preferably made of a highly heat insulating material.

It is preferable that the air volume changing means be operation-controlled in accordance with the value of the number of continuous images formed on the recording medium.

It is preferable that the first and second air passage forming means are constituted by a single fan device.

[Fourth Invention] In the fourth invention, a first temperature raising section and a second temperature raising section are provided inside the apparatus main body, and the gas in the vicinity of the first temperature raising section is sucked into the first invention. In the image forming apparatus, which is provided with a blowing unit that cools the temperature raising unit and sends the sucked gas to the second temperature raising unit to cool the second temperature raising unit, the second temperature raising unit side and the device body. An outside air intake passage communicating with the outside is provided, and the outside air can be introduced from the outside air intake passage by the blower unit, and the outside air can be blown to the second temperature raising unit together with the gas in the vicinity of the first temperature raising unit. Is characterized by.

[0061]

[Action]

[Operation of First Invention] In the first invention, when the number of image forming operations is small, the cooling operation time of the cooling means after the image forming operation is shortened. Conversely, if the number of image forming operations is large,
Increase the cooling operation time. [Operation of the Second Invention] In the second invention, the air passage changing means is provided in the vicinity of the opening, and the air passage changing means is moved to a position where the air passage to the outside of the apparatus body is blocked when the apparatus body is stopped. As a result, the optical system is cooled only by the rear rotation of one cooling fan. [Operation of the third invention] A third invention is provided with an air volume changing means for changing the ratio of the air volume per unit time formed by the first and second air passage forming means, and the continuous operation of the device, It is possible to always perform efficient cooling of each of the first and second heat generating portions irrespective of changes in various factors such as temperature rising gradients of the first and second heat generating portions. [Operation of the Fourth Invention] In the operation of the fourth invention, the air blower sucks the gas in the vicinity of the first temperature raising portion to remove the heat of the first temperature raising portion to cool it. This gas is sent to the second temperature raising section. At this time, although the temperature of the sucked gas is rising, the blowing means sucks the outside air of the apparatus main body through the outside air suction port and sends the outside air to the second temperature raising unit, so that the cooling efficiency is increased.

[0062]

【Example】

[First Embodiment of the Invention] FIG. 1 shows an image forming apparatus according to a first embodiment of the first invention.

As shown in the figure, 127 is an illuminating lamp, which irradiates an original placed on the original table glass 110 while moving it in the left-right direction of the figure to perform optical scanning, and an image of the original is displayed. A latent image 133 is formed by being exposed on the photosensitive drum 132 of the process cartridge via the imaging lens 131. Then, the latent image is visualized by the developing device 6.

On the other hand, the recording paper 134 is supplied from the cassette 135 by the paper feed roller 136 or the manual paper feed port 13
The sheet is manually fed through the sheet feeding roller 7 through the sheet feeding roller 1361 to the registration rollers 1372.

Then, the recording paper 134 is sent to the photosensitive drum 132 in synchronism with the above-mentioned image position, an image is formed by the transfer charger 138, and thereafter, the image is formed by the heat fixing device 126 via the conveyor belt 139. Is fixed and discharged outside the machine.

The cooling system in the image forming apparatus is composed of a cooling fan 111 as a cooling means, and the cooling fan 111 generates heat from the heat fixing device 126, an illumination lamp, a motor for driving the main body of the device (not shown), and the like. By discharging it outside, the temperature rise inside the main body of the device is prevented.

Then, the cooling fan 111 is controlled by the control means 140 so that the cooling operation time after completion of the image forming operation of the apparatus main body is proportional to the number of image forming operations.

FIG. 2 is a circuit diagram showing an embodiment of the control means of the present invention. Here, 101 is a switch, which receives a signal from the drive motor of the apparatus main body. 102 is a capacitor,
Reference numeral 103 is a comparator, 104, 105 and 106 are different resistors, and 107 is a main body cooling fan.

In this embodiment, the comparator 103 discharges the discharge voltage V _i of the capacitor 102 and the discharge voltage V _ref after the number of copies (for example, 50) as a predetermined number of times of image formation is performed. Compare with.

When V _i ≤V _ref (for example, when the number of copies is 50 or less), only for a fixed time (for example, 3).
The cooling fan 111 is rotated again for 0 seconds.

When V _i > V _ref (for example, when the number of copies is more than 50), the post-rotation time is lengthened in proportion to the number of copies.

In other words, in the present embodiment, the number of copies is proportional to the operating time (that is, the higher the number of copies, the higher the temperature rise of the main body). Therefore, this is replaced with the discharge voltage and is further proportional to the time. Utilizing that, the cooling fan 111
The post-rotation time is controlled.

This is shown in the graph of FIG. For example,
Time T _A of the case of the graph 108 to the discharge voltage becomes V _ref, since the T _B For graph 109, as long as each T _A, T _B time period or T _A, time proportional to T _B The cooling fan 111 is rotated. That is,
It means that the post-rotation time is controlled. By applying the present embodiment, the post-rotation time of the cooling fan increases in proportion to the number of copies, so that the temperature rise of the main body due to the increase in the number of copies (continuous copy) can be reliably prevented.

Moreover, since the post-rotation time is proportional to the number of copies, unnecessary cooling of the main body is not necessary, and the noise caused by the cooling fan 111 can be suppressed to the necessary minimum.

FIG. 5 shows the discharge curve of the capacitor in the second embodiment.

Here, the reference voltage V _ref (for example, the discharge voltage of the capacitor when copying 100 sheets) and V _i
The post-rotation time of the cooling fan 111 is determined based on the magnitude relationship with (discharge voltage).

For example, in FIG. 5, in the case of the graph 112 (for example, the number of copies is 80), V _ref > V _A, so the post-rotation time is T _A (for example, 60 seconds), and the graph 113 (for example, the number of copies). 120 sheets)
_{Since ref} <V _B , the post-rotation time is T _B (for example, 120
Seconds).

As described above, in the second embodiment, the post-rotation time is determined by determining whether the number of copies is larger or smaller than a predetermined number of copies, so that the circuit can be more simply constructed.

In the third embodiment, the post-rotation time of the cooling fan 111 according to the number of copies is controlled by the microcomputer.

Table 1 shows the post-rotation time of the fan depending on the number of copies.

[0081]

[Table 1] FIG. 6 shows a flow chart of the third embodiment, and FIG. 7 shows a circuit diagram.

That is, in FIG. 7, the number of copies is set by the "copy number setting key" 114, and the "copy start key" 11
When 5 is pressed, a signal is sent to the microcomputer 116, and as shown in the flowchart of FIG.
6 sends a command to the driver 117, and the cooling fan 1
07 works. Next, a fourth embodiment will be shown. FIG. 8 shows a flowchart and FIG. 9 shows a circuit diagram.

Here, a signal from a registration solenoid 119 (a solenoid that is turned on each time one sheet of paper is sent) is sent to a counter 120, and a switch S ₁ is sent according to the number X of copies.
121, the switch S ₂ 122, and the switch S ₃ 123 are O
Therefore, the driver 125 is instructed to operate the fan for a predetermined time.

Further, in FIG. 10, the main body cooling fan 129
In addition to the optical cooling fan 130 (cools the optical system 13)
The sectional view of the example which attached is shown.

The optical cooling fan 130 in this embodiment.
The post-rotation time is also proportional to the number of copies as described above. Further, in the first embodiment, the main body cooling fan 111 was used to cool the entire apparatus, but in the present embodiment,
The main body cooling fan 129 cools the inside of the apparatus main body, the optical cooling fan 130 cools the optical system 131, and so on. Further, in the apparatus of the type in which the optical system 131 is moved as in the present embodiment, the optical system 131 stops at a specific position after the copying operation is completed, so that the original platen glass 110 at the stop position becomes particularly hot.

Therefore, by changing the post-rotation time of the optical cooling fan 130 depending on the number of copies, it is possible to prevent excessive temperature rise of the original platen glass 110 and burns (touching the original platen glass immediately after a large number of copies).

[Embodiment of the Second Invention] FIG. 11 is a sectional view of an image forming apparatus embodying the first embodiment of the second invention.

Reference numeral 201 denotes a main body cooling fan (cooling is performed by discharging the air inside the apparatus main body 214 to the outside). Reference numeral 202 denotes a partition plate in the direction of arrow 203 by a driving means (not shown). It is movable as indicated by broken lines 202a → 202b. 204 is a main body cooling fan 2
01 indicates the flow of air discharged to the outside of the apparatus main body 209. Reference numeral 205 denotes an optical cooling fan that sucks outside air to prevent the temperature inside the optical system 208 from rising excessively. Reference numeral 206 denotes an air flow by the optical cooling fan 205.
A first mirror stand 207 includes a light source 207a.
210 is a process cartridge, and 211 is a fixing device.

Then, while illuminating the original 3 with the illumination lamp 207a of the first mirror base 207, the first mirror base 207 is moved left and right for optical scanning, and the image light of the original is passed through the mirror to the photosensitive drum 230. The latent image is formed on the exposed surface. Then, the latent image is visualized by the developing device 231.

On the other hand, the recording paper 232 is sent to the registration rollers 234 by the carrying roller 233 one by one.

Then, the recording paper 232 is sent to the photosensitive drum 230 in synchronism with the above-mentioned image position, an image is formed by the transfer charger 235, and thereafter, the image is formed by the heat fixing device 211 via the conveyor belt 236. Is fixed and discharged outside the machine.

Next, the contents of the first embodiment of the present invention will be described. The apparatus main body of the present embodiment is a fixed document table type (the first mirror table 207 scans and moves).

First, during the normal copying operation, the main body cooling fan 2
Reference numeral 01 cools the inside of the apparatus main body 214, and the optical cooling fan 205 cools the inside of the optical system 208. In this case, the flow of exhaust air by the main body cooling fan 201 is indicated by the arrow 20.
4 and the flow of exhaust air by the optical cooling fan 205 is in the direction indicated by arrow 206.

When the operation of the apparatus main body 209 is stopped, the partition plate 202 is rotated counterclockwise as indicated by an arrow 203, and the 202
It moves to the position of 202b via the position of a.

Then, an opening 216 is formed between the inside 214 of the apparatus main body and the inside 208 of the optical system, and the air flow in the direction of the arrow 204 is blocked, so that the air flow by the main body cooling fan 201 changes to the broken arrow 204a. The air flow indicated by the arrow 204a is substantially equal to the air flow 206 of the optical cooling fan 205.

Therefore, even if the operation of the apparatus main body 209 is stopped and the optical cooling fan 205 is also stopped at the same time, the flow of the exhaust air of the main body cooling fan 201 changes from the arrow 204 to the arrow 204a, so that the main body fan 201 is the optical cooling fan. The function of 205 can be shared.

In other words, "post-rotation" of the main body cooling fan 201
Is used for the “post-rotation” of the optical cooling fan 205.

In this way, the optical cooling fan 205 may be turned off at the same time when the operation of the main body of the apparatus is stopped, and the number of fans that rotate backward can be reduced from two to one, which greatly contributes to noise reduction.

Further, since the operation time of the optical cooling fan 205 is also reduced, it is only necessary to use an optical cooling fan having a short life and a low cost, which leads to cost reduction. The second in FIG.
The sectional view of the second embodiment of the invention is shown.

Here, below the main body cooling fan 201,
Similar to the first embodiment, a partition plate 212 which is movable (212 ← → 212a) in the direction of arrow 213 by a driving means (not shown) is provided. Also, since there is an opening 216,
The exhaust air of the main body cooling fan 201 is mainly divided into two directions, 204 to the outside of the apparatus main body and 204a to the inside 208 of the optical system.

That is, the flow 204a of exhaust air is 20
As a result, the inside of the optical system 208 is cooled along with the air flow of 6. The above is the state in which the apparatus main body 209 is in operation.

When the operation of the apparatus main body 209 is stopped, the partition plate 212 moves to the position of 212a. Therefore, the air flow in the direction of arrow 204 is blocked, and instead of arrow 2
Since the air flow in the 04a direction is enhanced, the optical cooling fan 205 can be stopped at the same time as the apparatus main body 209.

That is, after the apparatus main body 209 is stopped, the post-rotation optical cooling fan 205 of the main body cooling fan 201 functions. This eliminates the need for post-rotation of the optical cooling fan 205, which contributes to noise reduction and cost reduction as in the first embodiment.

Further, a sectional view of the third embodiment is shown in FIG.

Also in this case, as in the second embodiment, the opening 21 is formed.
6, the air discharged from the main body cooling fan 201 flows to the outside of the main body 209 of the apparatus and the inside 20 of the optical system.
It is divided into two, the flow 204 to 8.

Also in the present embodiment, even if the optical cooling fan 205 is stopped at the same time when the apparatus main body 209 is stopped, by rotating the main body cooling fan 201 backward, the arrow 204a
The air inside the optical system 208 can be cooled by using the air. Therefore, it is possible to obtain the same effects as those of the first and second embodiments.

[Embodiment of the Third Invention] FIGS. 15 and 16 are views showing the arrangement of an image forming apparatus according to the first embodiment of the third invention, which is the same as FIG. 22 used in the description of the prior art. The same reference numerals are given to the constituents, and the description thereof will be omitted. In the image forming apparatus according to this embodiment, the fan device 3
18, the fan device 318 discharges heat generated from the heating and fixing device 315 and the like to the outside of the machine, but the case 318a forming the air passage of the fan is provided with the wind direction switching plate 319. ing.

One end of the wind direction switching plate 319 is rotatably attached to the main body by a shaft 323.
9 is urged clockwise by a spring member (not shown) as shown in FIG. 15, and its other end is normally in contact with the case 318a.

17 and 18 show the detailed structure of the wind direction switching plate 319. As shown in these drawings, an engaging portion 320 that is integral with the wind direction switching plate 319 is formed substantially at the center thereof, and one end of a link member 322 is pivotally supported by the engaging portion 320 and the other end is movable. The movable iron core 324 is pivotally supported by the iron core 324, and the movable iron core 324 is attached to the solenoid 321.

In the state shown in FIG. 15, the solenoid 321
Is not energized, and as a result, the movable iron core 324 is projected by the above-mentioned spring member.
Is in contact with the case 318a. In this state, the wind discharged by the fan device 318 is the wind direction switching plate 31.
9. The flow rectifying plate 325 flows in the direction indicated by the arrow C, and joins the wind D formed by the other fan device 317 to flow near the lower surface of the original platen glass 302 for cooling.

As described in the prior art, for example, the temperature rising gradient of the developing device 306 is considerably smaller than that of the original platen glass 302. That is, the wind C exhausted by the fan device 318 for a while after the start of the operation.
Since the temperature of is much lower than that of the platen glass 302,
The cooling effect is further enhanced as compared with the case where the fan device 317 alone is used to cool the glass as in the conventional example. As a result, FIG.
As shown in FIG. 4, the slope of A, that is, the surface temperature curve of the platen glass 302 becomes small like A1, and the time to reach saturation also becomes longer from X to X1. Further, the amount of heat transferred from the platen glass 2 side to the periphery of the developing device 306 is also reduced, so that the curve B becomes B1, and the time to reach saturation also becomes Y to Y1.

In other words, the exhaust air of the fan device 318 is combined with that of the fan device 317 to increase the air volume, so that it is possible to reduce the temperature rise and the temperature gradient of the original platen glass 302, the developing device 306 and other surroundings.

However, in FIG. 24, when the elapsed time from the start of operation exceeds X1 and reaches saturation, the platen glass 3
Although the temperature of 02 does not change, it enters a region where only the temperature around the developing device 306 rises. Therefore, the platen glass 2
The temperature difference between the surface and the developing device 6 gradually decreases, and the effect of cooling the platen glass 2 by the exhaust of the fan device 18 decreases.

Therefore, the exhaust temperature of the fan device 18 is detected by a temperature sensor (not shown in the figure), and when a certain temperature is reached, the solenoid 21 is energized to attract the movable iron core 24. Then, the wind direction switching plate 19 is rotated to the position shown in FIGS. 2 and 4 via the link member 22 to rotate the cover 18b.
The wind C that had been heading toward the platen glass 2 until then.
Is discharged directly out of the machine as indicated by arrow E.

Therefore, the heat exhausted by the fan unit 18 does not flow toward the platen glass 2, so that the cooling efficiency of the glass 2 is not significantly reduced.

Further, the wind direction switching plate 19 is not made of a metal plate having a high heat conductivity but is made of a resin having a lower resinity, so that the heat conduction of the exhaust heat of the fan unit 18 to the periphery of the glass can be suppressed and the efficiency can be improved. Cooling can be performed.

As described above, according to this embodiment, as shown in FIG. 10, even if the respective saturation temperatures x and y of the temperature curves A and B do not decrease, the temperature gradient until saturation is reduced. In addition, the effect of the present embodiment can be expected effectively in a small-sized image forming apparatus for individuals, which has a practically short continuous operation time.

Furthermore, in this embodiment, since the solenoid is not normally energized, it is possible to contribute to the prevention of temperature rise in terms of heat generation of the solenoid itself.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same components as those described above are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, a fan device 326 is provided, and unlike the case of the first embodiment, the fan device 326 raises the temperature by the heat transmitted from the periphery of the original platen glass 302 and the heat fixing device 315. It also has a cooling function for the periphery of the device 306. The fan device 326 takes in the cool air H from outside the machine, sucks the cool air through the vicinity of the lower surface of the original platen glass 302 as shown by the arrow F, and at the same time the heat around the heat fixing device 315 and the developing device 306 as shown by the arrow G. It is being taken out of the machine.

Part of the case 327 of the fan unit 326
Is rotatably supported by a shaft 328 as an air volume switching plate. At the initial stage of the continuous operation, that is, while the temperature rise gradient of the platen glass 302 surface is higher than other portions, the air volume switching plate 327 is rotated counterclockwise as shown in FIG. The amount of air flow F from is sucking in much more air than G.

After that, when the temperature rise on the surface of the glass 302 approaches a saturation state to some extent, the air volume switching plate 327 is rotated clockwise as shown in FIG. The surface of the glass 302 and other parts can be cooled well.

The switching operation of the air volume switching plate 327 is as follows.
Similar to the case of the first embodiment, it can be performed using a solenoid and a temperature sensor.

As described above in the first and second embodiments, regardless of whether the number of fan units is one or a plurality of fan units, the cooling of the entire image forming apparatus is balanced with good balance. Needless to say, it can be performed effectively.

Next, the third embodiment of the present invention will be described with reference to FIG.
1 and FIG. 22 will be described. The configuration of the image forming apparatus according to this embodiment is similar to that shown in FIG.
22 shows the relationship between the set number of copies and the amount of air discharged by the fan device 316 per unit time.
17 shows that.

In this embodiment, the air volume by the fan device is changed according to the number of copies made by the user. For example, the number of copies set by the user by the copy number setting means is 10.
Depending on whether it is within the number of sheets or 11 or more, the air volume of the fan device 316 is selected from two types of J and J1.
The air volume of 7 is automatically selected from K and K1. Although not shown here, the air volume is selected by controlling the rotation speed by, for example, the fan rotation speed control means.

J and K are temperature rise curves B and A shown in FIG.
In the case of, the air volumes are J1 and K1 and have a relationship represented by the following equation.

J1 / J> K1 / K When comparing the temperature rises A and B in the continuous copying operation of the original platen glass 302 and the developing device 306, the curve A has a larger rising gradient and a higher saturation temperature, and is saturated. Short time to reach. Of these, the glass having the largest rising gradient is the glass 30.
2 Due to the reason that the distance between the lower surface and the heat source which is the illumination lamp 301 is smaller than that between the developing device 306 and the heat fixing device 315, on the contrary, after the completion of the entire copying operation (the fan devices 316 and 317 are stopped). Even when the temperature of both of them falls, the glass 302 surface has a larger descending gradient, and the time required to return to the initial temperature is shorter.

When the time required to return to the initial temperature is T1 (glass surface) and T2 (around the developing device),
These ratios T2 / T1 are expressed by the following equations in comparison with the ratio Y / X in the case of increase.

T2 / T1> Y / X The reason for such a relationship is that the glass 302 is more outside than the periphery of the developing device 306 in the entire device and is close to the outside air, and the heat dissipation efficiency is good.

Considering the gradients of temperature rise and fall of both, the glass surface is more likely to be hot than the developing device, but is more likely to be cooled than that ratio.

Further, as a result of the experiments conducted by the inventors of the present invention with a copying machine, the temperature change on the glass surface at 10 sheets / minute increased by about 3 degrees in the first minute (corresponding to copying 10 sheets). After that, when the operation was stopped (fan stop), it took about 4 minutes to return to the initial temperature. In the vicinity of the developing device 306,
They were about 0.5 degree and 6 minutes, respectively.

In the low-speed copying machine of about 10 sheets / minute like this experimental machine, a long-time continuous copying operation of several hundred sheets is not often performed, and the ratio of continuous operation of several sheets is very large. Further, since the interval between the continuous operation and the next continuous operation is relatively longer than that of the medium-high speed machine, there is substantially no problem even if the air volume is reduced as described above. This is more effective in terms of fan drive power and wind noise as the personal computer becomes smaller and operates at a lower speed.

As described in detail above, the wind direction switching plate 3
19 and the air volume switching plate 327 to change the air volume ratio, it is possible to efficiently and efficiently cool each of them independently of changes in various factors of the temperature rising gradient of the platen glass and the developing device.

Further, as a result of being able to reduce the rising gradient until the temperature on the glass surface reaches saturation, the temperature rises substantially in a small image forming apparatus for individuals, etc., which has a shorter continuous operation time in actual use. It is possible to provide a small device.

Furthermore, by utilizing the fact that it is easy to return to the initial temperature substantially in the glass portion where the temperature drop gradient is large between the continuous operation and the next continuous operation, for example, during continuous operation with 10 or less copies. By reducing only the air volume, the rotation speed of the fan can be lowered to contribute to the prevention of noise such as wind noise.

[Fourth Embodiment of the Invention] FIG. 25 is a front sectional view of the present invention. Reference numeral 401 denotes a box-shaped apparatus main body, and an original placing table 40 made of glass or the like is provided on the apparatus main body 401.
2 is provided, and the document A is placed on the document placing table 402 for use. The original A is scanned by the irradiation light of the illumination lamp 403 provided below the original placing table 402, and the reflected light L is sequentially reflected by the mirrors 404 to 409 and is exposed on the photosensitive drum 410. The document placing table 40
2, the illumination lamp 403, the mirrors 404 to 407, etc. are the second temperature raising unit 450.

The photosensitive drum 410, whose surface charge distribution has been flattened by the charging device 411 before the exposure, forms a latent image through the above-described exposure process and then develops the latent image by the developing device 4.
Develop with 12 toners.

On the other hand, the transfer paper 41 in the paper feed cassette 413 is
The sheets 4 are fed one by one by the sheet feeding roller 415, and then enter the nip portion of the registration roller 417 via the guide member 416.

In addition to the above-described cassette paper feeding, the present apparatus can also be manually fed one by one. In this case, the transfer paper 414 is manually inserted along the upper surface of the manual feed tray 418 up to the vicinity of the feed roller 419. At this time, the rotation of the feeding roller 419 is started as detected by the transfer sheet detecting means (not shown) near the feeding roller 419,
It is sent to the registration roller 417 as in the case of the cassette paper feeding.

As described above, the transfer paper 414 fed by the cassette 413 or the manual feed is the registration roller 4
17, the photosensitive drum 41 is synchronized with the toner image.
Then, the toner image is transferred by the charger 420. After that, the transfer paper 414 is sent to the fixing device 422 by the conveyor belt 421 to fix the toner image, and is discharged onto the paper discharge tray 423. The fixing device 422 has a heating roller 422a and a pressure roller 422b. Further, the residual toner remaining on the photosensitive drum 410 after the transfer is scraped off from the photosensitive drum 410 by the cleaning device 424.

The fixing device 422 and the chargers 411 and 42
0 and the like are the first temperature raising unit 451. Then, the first temperature raising unit 4
A partition 452 is provided between 51 and the second temperature raising unit 450 to prevent disturbance of the image light L formed by the second temperature raising unit 450 and intrusion of dust.

Inside the apparatus main body 401, that is, the partition wall 4
A cross flow fan 428 is provided between 52 and the fixing device 422 as a blowing unit that sucks gas near the second temperature raising unit 451. This cross flow fan 428
26 has a suction port 255 on the first temperature raising unit 251 side, extends from the front side of the apparatus main body 401 toward the back side, and has blades 453 provided therein.
The blade 453 is rotated by a motor 429 in the direction of arrow C in the figure.

Reference numeral 454 is a first air passage provided integrally with the front half of the cross flow fan 428. The first air passage 454 penetrates the partition wall 452 and the second temperature raising unit 45.
It communicates with the 0 side. In addition, the cross flow fan 42
8 is connected to one end side of an intake duct 430 as an outside air intake passage. The other end of the intake duct 430 is shown in FIG.
7 (A), it is connected to the suction port 458 provided in the rear wall 401a of the apparatus body 401 and communicates with the outside of the apparatus body 401. The suction port 455 is provided with a filter 456.

On the other hand, a second air passage 457 is provided for the rear half of the cross flow fan 428. The second air passage 457 communicates with both the suction port 455 and the suction port 458, penetrates the partition wall 452, and then the second temperature raising unit 450.
Is in communication with. A discharge port 459 is provided on the side surface of the apparatus main body 401 opposite to the first and second air passages 454 and 455.

In the above structure, when the blades 453 are rotated by the motor 429, the gas in the vicinity of the second temperature raising portion 451 is sucked into the cross flow fan 428 through the suction port 455 as shown by arrow E. As a result, the fixing device 42
The heat generated in 2 and the ozone generated in the chargers 411 and 420 are removed to cool the portion.

Most of the sucked gas is the first air passage 4
It is sent to the second temperature raising unit 450 side via arrow 54 as shown by arrow F. On the other hand, at the same time, the outside air outside the apparatus main body 401 is sucked into the intake duct 430 through the suction port 458 by the suction force of the blades 453 as shown by the arrow D. This outside air is mixed with a part of the gas sucked from the suction port 455 in the cross flow fan 428 to lower the temperature of the gas.

After that, the air-fuel mixture of the gas and the outside air is sent to the second temperature raising section 450 side through the second air blowing passage 457 as shown by an arrow G. Then, together with the gas sent from the first air passage 454, the illumination lamp 403 and the mirrors 404 to 40.
7. After cooling the document placing table 402 and the like, the document placing table 402 and the like are discharged to the outside of the apparatus main body 401 through the ejection port 459.

As described above, in the present invention, the second temperature raising unit 45
The cooling efficiency at 0 is improved.

Further, since both the first temperature raising section 451 and the second temperature raising section 450 are cooled by only the single cross flow fan 428, the number of parts is small, the manufacturing cost can be suppressed, and the apparatus can be downsized. ， We can realize weight reduction. Further, since the amount of blown air itself does not change, there is no increase in wind noise or noise. Furthermore, the transfer paper 4 on the conveyor belt 421 is blown.
It is possible to accurately send the toner to the fixing device 422 without disturbing the behavior of the toner.

When a temperature rise experiment is conducted by the method of the present invention, if the wind speed of the gas sucked from the suction port 455 and the outside air sucked from the intake duct 430 are about 5: 3, different fans are used. It has been found to give results comparable to those used.

FIG. 27B shows another example of the structure of the blowing means. The cross roller fan 431 is provided with blades (not shown), and has a suction port 455 and an air passage 460. On the other hand, on the back end side of the cross roller fan 431,
An intake duct 430 leading to the intake port 458 is provided,
Inside the duct 430, blades 432 similar to an axial fan are provided. This blade 432 is a cross roller fan 43.
Since it is mounted on the same rotary shaft as the blade in 1, the number of parts does not increase. In addition, the duct 430 communicates with the second temperature raising unit 450 side via the air passage 461.

In this embodiment, the gas and the outside air are mixed on the side of the second temperature raising unit 450. Others can obtain the same effects as those of the first embodiment.

The present invention is not limited to a copying machine, but may be a printer,
Not only can it be used for cooling various office equipment such as facsimiles, but it can also be applied to air conditioning equipment for buildings.

[0155]

【The invention's effect】

[Effects of the first invention] According to the first invention, when the number of image forming operations is large by making the cooling operation time after the image forming operation of the cooling means in the apparatus main body proportional to the number of image forming operations. Can prevent an excessive temperature rise in the apparatus body.

When the number of image forming operations is small,
Since extra post-rotation is eliminated, it is possible to obtain effects such as waste of power consumption and generation of noise to a minimum.

[Effect of Second Invention] According to the second invention,
In an image forming apparatus having a fan for cooling the upper component of the device body and a fan for cooling the lower component of the device body, an opening and a movable partition plate are provided at the boundary between the upper component and the lower component. As a result, the following effects can be obtained.

Since the cooling is performed by using the post-rotation after the main body of the apparatus is stopped, only one cooling fan needs to be used, so that the noise can be reduced (silence).

Similar to the above, since it is sufficient to use only one cooling fan, power consumption can be saved (energy omitted).

Since the cooling fan that does not rotate afterward does not need to add the amount of time after rotation to the life, the cost is low (1
Cooling fan (lower rank) can be adopted (cost reduction).

[Effects of Third Invention] According to the third invention,
Since the air volume changing means for changing the ratio of the air volume per unit time formed by the first and second air passage forming means is provided, continuous operation of the device, intermittent operation, or the first and second operation is performed. It is possible to constantly and efficiently cool each of the heat generating portions irrespective of changes in various factors such as temperature rise gradients.

[Effect of Fourth Invention] According to the fourth invention,
The gas whose temperature has risen by cooling the first temperature raising section is cooled by the outside air to lower the temperature, so that the cooling efficiency in the second temperature raising section improves.

Further, since both the first temperature raising part and the second temperature raising part are cooled by a single blowing means, the number of parts is small, the manufacturing cost can be suppressed, and the size and weight of the device can be reduced. it can. Further, since the amount of blown air itself does not change, there is no increase in wind noise or noise.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the first invention.

FIG. 2 is a circuit diagram of a control means shown in FIG.

FIG. 3 is a graph showing a relationship between discharge voltage of a capacitor and time in the control circuit of FIG.

FIG. 4 is a schematic configuration diagram of an image forming apparatus of a conventional example related to the first invention.

5 is a graph showing a relationship between discharge voltage of a capacitor and time as a second embodiment of the control circuit of FIG.

FIG. 6 is a flowchart of a third embodiment of the first invention.

FIG. 7 is a circuit diagram of a third embodiment of the first invention.

FIG. 8 is a flow chart of a fourth embodiment of the first invention.

FIG. 9 is a circuit diagram of a fourth embodiment of the first invention.

FIG. 10 is a schematic configuration diagram of an image forming apparatus according to a fifth embodiment of the first invention.

FIG. 11 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the second invention.

FIG. 12 is a schematic configuration diagram of an image forming apparatus according to a second embodiment of the second invention.

FIG. 13 is a schematic configuration diagram of an image forming apparatus according to a third embodiment of the second invention.

FIG. 14 is a schematic configuration diagram of an image forming apparatus of a conventional example related to the second invention.

FIG. 15 is a sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment of the third invention.

FIG. 16 is a sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment of the third invention.

FIG. 17 is a perspective view showing a detailed configuration of an airflow direction switching plate in the image forming apparatus.

FIG. 18 is a perspective view showing a detailed configuration of an airflow direction switching plate in the image forming apparatus.

FIG. 19 is a sectional view showing a schematic configuration of an image forming apparatus according to a second embodiment of the third invention.

FIG. 20 is a sectional view showing a schematic configuration of an image forming apparatus according to a second embodiment of the third invention.

FIG. 21 is a graph showing the relationship between the set number of copies and the discharge air volume according to the third embodiment of the present invention.

FIG. 22 is a graph showing the relationship between the set number of copies and the discharge air volume according to the third embodiment of the present invention.

FIG. 23 is a schematic sectional view showing a configuration of a conventional image forming apparatus.

FIG. 24 is a diagram showing a temperature rise curve of each part in the image forming apparatus.

FIG. 25 is a front sectional view of a copying machine to which the fourth invention is applied.

FIG. 26 is a perspective view around the cross flow fan used in FIG. 25.

27 (A) is a perspective view in which the upper part of the apparatus main body of FIG. 25 is cut away, and FIG. 27 (B) is a perspective view showing another configuration example of the blowing unit.

FIG. 28 is a schematic sectional view of a first conventional example of the fourth invention.

FIG. 29 is a schematic sectional view of a second conventional example relating to the fourth invention.

[Explanation of symbols]

 111 cooling fan 129 main body cooling fan 130 optical cooling fan 201 main body cooling fan 202 partition plate 205 optical cooling fan 209 device body 318 fan device 319 airflow direction switching plate 326 fan device 327 air volume switching plate 451 first temperature raising unit 450 second temperature raising Part 454 First air passage 457 Second air passage

Claims (11)

[Claims] 1. An image forming apparatus comprising a cooling means for cooling heat generated during an image forming operation in an apparatus body, wherein a cooling operation time of the cooling means after the image forming operation of the apparatus body is completed An image forming apparatus comprising a control unit for controlling the number of forming operations in proportion to the number of forming operations. 2. The image forming apparatus according to claim 1, wherein the number of times of the image forming operation is counted by the number of images of the transfer material on which the image is formed. 3. A capacitor is charged during image forming operation,
The image forming apparatus according to claim 1, further comprising a control circuit that determines an operating time of the cooling unit after the operation of the apparatus main body is completed in proportion to a discharge voltage of the capacitor after the image formation is completed. 4. An image having a cooling fan for cooling an upper component of the apparatus main body and a cooling fan for cooling a lower component of the device main body, and having an opening at a boundary portion between the upper component and the lower component. The image forming apparatus according to claim 1, wherein an air passage changing unit is provided near the opening. 5. The image forming apparatus according to claim 4, wherein when the apparatus main body is stopped, the air passage changing unit moves to a position that blocks an air passage to the outside of the apparatus main body. 6. A first heat generating portion having at least one illuminating means for irradiating a document placed on a document placing table to perform optical scanning, and image information obtained by the optical scanning. A second heat generating portion having at least one fixing means for fixing to the medium as a heat source; and a first air passage forming means for forming an air passage around the first heat generating portion to prevent an excessive temperature rise.
An image forming apparatus comprising: a second air passage forming means for forming an air passage around the second heat generating portion to prevent an excessive rise in temperature, the image forming apparatus being formed by the first and second air passage forming means. An image forming apparatus comprising: an air volume changing unit that changes a rate of an air volume per unit time. 7. The air flow rate changing means includes the first and second air flow rate changing means.
7. The image forming apparatus according to claim 6, further comprising: an air flow direction switching plate that changes a passage path of an air passage formed by at least one of the air passage forming means. 8. The image forming apparatus according to claim 7, wherein the wind direction switching plate is made of a highly heat insulating material. 9. The image forming apparatus according to claim 6, wherein the air volume changing means is controlled in operation in accordance with a value of the number of continuous images formed on the recording medium. 10. The image forming apparatus according to claim 6, wherein the first and second air passage forming means are constituted by a single fan device. 11. A first temperature raising section and a second temperature raising section are provided inside the apparatus main body, and gas near the first temperature raising section is sucked to cool the first temperature raising section, In an image forming apparatus provided with a blowing unit that sends the sucked gas to the second temperature raising unit and cools the second temperature raising unit, an outside air suction passage that connects the second temperature raising unit side and the outside of the apparatus main body is provided. An image forming apparatus, which is provided so that the outside air can be introduced from the outside air suction passage by the air blower, and the outside air can be blown to the second temperature raising unit together with the gas in the vicinity of the first temperature raising unit.