JPH07140884A - Image forming device - Google Patents

Abstract

PURPOSE:To miniaturize a cooling means and to save lavor by providing movable partition plate on a ventilating duct, adjusting the quantity the air in the duct according to the necessity of each heat source and preferentially and surely cooling a part required for more cooling. CONSTITUTION:Temperature sensors 77 and 76 are disposed on a fixing device 64 and a power source 68 respectively to detect their temperatures and output the signals to a controller 69, so that the partition plate 75 can be timely rocked with the signals. When a control circuit judges that it is necessary that the fixing device 64 is preferentially cooled by the temperatures detected by the sensors 76 ad 77, the partition plate 75 is turned to a solid line position with the signals emitted from the control circuit and the quantity of the air in a duct 70 connected to a fan 3 from the fixing device 64 is made large to accelerate the cooling of the device 64. On the contrary, when the power source 68 is preferentially cooled, the partition plate 75 is turned to a chain line side to increase the quantity of the air in a duct 71 and quickly cool the power source 68.

Description

Detailed Description of the Invention

[0001]

[Object of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus utilizing an electrostatic transfer process, such as an electrostatic copying machine and a printer, and more particularly to a cooling device therefor.

[0002]

2. Description of the Related Art In the known image forming apparatus as described above, a driving source for driving each internal mechanism, a fixing unit for fixing an unfixed image carried on a transfer material, and each section in the apparatus. Since there is a heat source such as a controller that controls the operation of the device and a part that may be deteriorated in function due to an increase in temperature, it is essential to cool these parts so that a predetermined function can be maintained.

This will be briefly described below. First, a typical example of this type of image forming apparatus will be roughly described. FIG. 6 is a side sectional view schematically showing this type of image forming apparatus, in which the transfer material P in a transfer material accommodating portion such as a cassette arranged below the apparatus main body is taken out by the paper feed roller 52, The image carrier 60 in the cartridge 86 and the transfer roller 6 are passed through the guide path 55, the pair of conveyance rollers 54, the pair of registration rollers 57, and the sensor lever 59 and the conveyance path 61.
3 reaches the opposite transcription site.

By this time, the surface of the image carrier 60 is uniformly charged by a charging means (not shown), and the image-modulated light beam L is projected from the scanner unit 50 onto this charged surface to form an electrostatic latent image. It is assumed that the toner image formed, and further, the toner image formed by applying toner to the latent image from a developing device (not shown) reaches the transfer portion at the same timing as the transfer material P. .

Next, the toner image on the image carrier side is transferred to the transfer material by the action of the transfer bias applied to the transfer roller.
Thus, the transfer material carrying the toner image is separated from the image carrier, conveyed to the left in the drawing and reaches the fixing device 64, passes through the nip portion of the fixing roller pair 65 having a heat source inside, and the toner image is transferred. It is assumed that the transfer material is fixed and fixed to the material, and then the transfer material is discharged to the tray 67 through the discharge roller pair 66.

As described above, in the apparatus having such a structure, there are a heat source such as a motor for driving each part and a fixing device which itself generates a large amount of heat, and a controller for controlling the whole is further provided. Since there is a member that must avoid the temperature rise, a cooling means is required in order to always operate the whole stably.

"FIG. 7" is a view of the apparatus of "FIG. 6" seen from the opposite side (back side of the drawing), and "FIG. 8".
7 is a schematic view of the part as viewed from the direction of arrow A in FIG. 7 except for the image forming portion shown in FIG.

In FIGS. 7 and 8, reference numeral 64 is a fixing device, 68 is a power source for driving each part in the device, and 69.
Is a controller for controlling the operation of the main body. As shown in the figure, the fixing duct 70 and the power supply duct 71 are provided in the main body device.
Are extended in the vertical direction, and these ducts are fixed to the main body side plate 72. A cooling fan 73 is attached to the upper ends of the ducts 70 and 71 and faces a louver 74a provided on the exterior of the main body.

With such a structure, heat from the fixing device, which is the main heat source in this type of device, and the drive motor is discharged to the outside through the duct 70 and the duct 71 to reduce the temperature rise and at the same time. The temperature of the controller 69 is also prevented from rising due to the air flow generated inside the machine.

However, with the cooling means having such a structure, since cooling is always performed with a constant air flow, waste is inevitable. That is, even with one device,
When this is used in a high temperature environment, in a low temperature environment, or when continuous printing is performed or intermittently, there is a large change in the degree of temperature rise of each heat source.

When the known cooling means as described above is used, it is premised that a sufficient cooling effect is obtained even in the most unfavorable conditions that may occur. The amount of air flow is added, which inevitably leads to an increase in the size of the fan and an increase in power consumption.

The present invention has been made to cope with such a situation, and a duct connecting two heat sources and a cooling means such as a cooling fan is provided between one of the heat sources and the cooling means. By providing a means that can be selectively coupled, it is always possible to preferentially cool the site that requires the most cooling, downsizing of the drive source for cooling,
An object of the present invention is to provide an image forming apparatus provided with a cooling device capable of effectively cooling each part in the main body device while limiting the amount of air required for cooling.

[0013]

[Constitution of the invention]

In order to achieve the above object, the present invention provides an image forming apparatus having a plurality of heat sources or members for avoiding temperature rise, and a cooling means. A plurality of ducts that connect the source or the member to the cooling unit, a switching unit that switches the plurality of ducts and is displaced so as to increase the amount of air supplied to the predetermined duct, and the state of the heat source or the member It is characterized by comprising a detecting means for detecting a change, and activating the switching means by a signal from the detecting means.

With such a structure, it is possible to reduce the size of the cooling means, save labor, reduce noise, and reduce costs.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS "FIG. 1" shows a first embodiment of the present invention, and shows the image forming apparatus viewed from the same position as in "FIG. 8" described above. Are denoted by the same reference numerals. The fixing duct 70 as shown
A swingable partition plate 75 is provided at the end of the side plate 72 that divides the power supply duct 71 from the power duct 71 and at a portion near the cooling fan 73. As will be described later, the partition plate 75 can selectively take the solid line position and the chain line position shown in the figure, whereby the air volume of the fixing device side duct 70 (solid line position) and the power source side duct (chain line position). Can be increased.

The fixing device 64 and the power source 68 are provided with temperature sensors 77 and 76, respectively, for detecting the temperatures of these members and outputting the signals to the controller 69. Thus, the partition plate 75 can be appropriately swung.

FIG. 2 is a perspective view of an essential part showing a means for swinging the partition plate 75. A bearing 78 is attached to the upper end of the side plate 72, and a sector gear 75b provided at an end of a partition plate 75 provided on a shaft 75a pivotally supported by the bearing 78 is provided with a gear provided at a rotary shaft of a step motor 79. 80 meshes with the sector gear 75b.

The step motor 79 is a controller 6
It is assumed that the partition plate 75 is connected to the control circuit 9 and rotates in the forward and reverse directions according to a signal from the control circuit to swing the partition plate 75 via the gear 80 and the sector gear 75b.

With this structure, for example, according to the temperatures detected by the sensors 76 and 77,
When the control circuit determines that the fixing device 64 needs to be preferentially cooled, the partition plate 75 is rotated to the position shown by the solid line in FIG. The amount of air in the interior increases, which promotes cooling of the fixing device. On the contrary, when the control circuit determines that the power supply 68 needs to be preferentially cooled, the partition plate rotates to the side of the chain line in FIG. 1 to increase the air volume of the duct 71 and quickly cool the power supply 68. can do.

FIG. 3 shows another embodiment of the present invention. The arrangement of the power source, the fixing device and the like in the image forming apparatus, the duct configuration for them, etc. are the same as those in FIG. Therefore, description of their control and operation will be omitted.

In this apparatus, the duct 8 is attached to the scanner unit 50 which is apt to cause troubles due to temperature rise.
1 is provided, and this duct 81 opens at an appropriate position on the fixing device side duct 70.

A second partition plate 82 is swingably provided at a portion where the duct 81 is opened to the duct 70, and the partition plate 75 and the swing structure described in the embodiment of FIG. Depending on the detection value of the temperature sensor 83 provided in the scanner unit 50, the fixing device 64 and the power source 6 are positioned when the partition plate 82 is positioned at any of the solid line and the dotted line in the figure.
In the same manner as in No. 8, necessary members are selectively cooled.
It will be readily understood that it is also possible to cool the cartridge in the main unit instead of the scanner unit 50.

FIG. 4 shows still another embodiment. This apparatus has the structure and operation of the fixing device 64, the power source 68, the ducts 70 and 71, the cooling fan 73, etc., for the fixing device 64, the power supply 68, and the like. Similar to that shown.

Further, in this apparatus, the duct 81 connected to the scanner unit 50 is connected to the second cooling fan 85 arranged facing the louver 74b on the side of the apparatus main body, and the fan 85 is connected to the second cooling fan 85. The duct 84 opens to the fixing device 64 side. At the confluence of the ducts 81 and 84, a partition plate 82 having the same structure as the partition plate 75 described above and oscillating between the solid line and the dotted line in the figure according to an instruction from the control circuit is provided. .

With this structure, the heat from the power source 68 is discharged by the duct 71 and the fan 73, the heat from the scanner unit 50 is discharged by the duct 81 and the fan 85, and the heat from the fixing device 64 is discharged to the duct 70. Fan 7
3 and the duct 84 and the fan 85.

FIG. 5 shows still another embodiment, and the constitution of this apparatus is basically the same as that shown in FIG. 4 and the fixing device 6 in the apparatus of this embodiment is shown.
4, the power source 68, the sensor provided in the scanner unit 50 are omitted, and each partition plate 7 is provided depending on the image forming mode.
5 and 82 are operated.

That is, in this apparatus, when a print signal is input to the control circuit and printing is being performed (print mode), the partition plates 75 and 82 take the positions indicated by the solid lines in the figure to cool the fixing device. I try to hasten it.

In the standby mode in which printing is not performed, the partition plates 75 and 82 take the positions of the chain lines to reduce the air volume from the fixing device and increase the air volume from the power supply 68 and the scanner unit 50. There is.

It is well known that the amount of heat generated by the fixing device during operation of the device is larger than that of the power source, the scanner unit, etc. Therefore, by constructing in this way, the actual temperature of each part is raised. Cooling that substantially matches the temperature tendency is performed, and the configuration of the control means can be simplified. Needless to say, if it is desired to change the cooling conditions other than the above-mentioned members, another mode suitable for the cooling conditions can be set.

[0030]

As described above, according to the present invention,
A movable partition plate is provided in a ventilation duct for cooling a plurality of heat sources arranged in the main body of the apparatus, and the air volume of the duct is adjusted according to the need of each heat source, and further cooling is required. Since the parts are configured to be cooled preferentially and reliably, there is no need to make the cooling fan larger than necessary or to increase the rotation speed silently, and the cooling means can be made compact, labor-saving, and low noise. It has a great contribution.

Further, it is possible to prevent functional deterioration due to temperature rise even at a portion other than the heat source, and by setting the adjustment of the air volume to each duct so as to match the actual operation mode of the main body of the sensor. It is possible to reduce the cost by eliminating the requirement.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part showing a first embodiment of the present invention.

FIG. 2 is a perspective view of an essential part showing a configuration of an operating means of the partition plate.

FIG. 3 is a side sectional view of an essential part showing a second embodiment of the present invention.

FIG. 4 is a side sectional view of a main part showing a third embodiment of the present invention.

FIG. 5 is a side sectional view of a main part showing a fourth embodiment of the present invention.

FIG. 6 is a side sectional view of a known image forming apparatus suitable for applying the present invention.

FIG. 7 and

FIG. 8 is an explanatory diagram showing an arrangement of a heat source such as a power supply and a fixing device in which the above apparatus is arranged.

[Explanation of symbols]

 50 Scanner Unit 60 Image Carrier 64 Fixing Device 68 Power Supply 69 Controller 70, 71, 81, 84 Duct 73, 85 Cooling Fan 75, 82 Partition Plate 76, 77, 83 Temperature Sensor 79 Step Motor 86 Cartridge

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kimi Tsuka Eiichiro 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masao Amano 3-chome Shimomaruko, Ota-ku, Tokyo 30 No. 2 Canon Inc.

Claims (5)

[Claims] 1. An image forming apparatus having a plurality of heat sources or members for avoiding temperature rise, and a cooling unit, wherein a plurality of ducts connecting the heat sources or the members to the cooling unit are provided. The switching means includes a switching means for switching a plurality of ducts and displacing the duct so as to increase the amount of air supplied to the predetermined duct, and a detection means for detecting a change in the state of the heat source or the member. An image forming apparatus characterized by operating a means. 2. The image forming apparatus according to claim 1, wherein the heat source is a fixing device and a power source. 3. The image forming apparatus according to claim 1, wherein the members whose temperature rise is to be avoided are a scanner unit and a cartridge. 4. The image forming apparatus according to claim 1, wherein the state change detecting means is a temperature sensor. 5. The method according to claim 1, wherein the state change detecting means is means for detecting whether the apparatus main body is in image formation or non-image formation. Image forming apparatus.