JPH06194920A - Image forming device - Google Patents

Abstract

PURPOSE:To effectively discharge heat from an image forming device by means of a simple structure without increasing power consumption by providing independently of an electric motor a second exhaust member which is driven along with an operation for carrying paper in the image forming device. CONSTITUTION:The second exhaust member 8 in the form of a fan is fixed on a shaft 7-4. After printing is started and a carry roller 7-3 is rotated in the direction shown by the arrow R by the drive of a motor for ejecting paper in the direction shown by the arrow Y, the second exhaust member 8 is also rotated in the same direction along with the rotation of the shaft 7-4. Consequently, warm air in the image forming device is discharged through a louver opening 9-1 provided in an outer case 9. Therefore, because the need for an extra power source for the second exhaust member 8 is eliminated by fixing the second exhaust member 8 to the shaft 7-4 of the carry roller, the heat discharging performance of the image forming device can be improved by the simple structure without increasing power consumption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a laser beam printer, and an LED printer, in which a toner image formed on a sheet by electrophotography is heated. The present invention relates to an image forming apparatus provided with a fixing device for fixing to paper and an exhaust member for discharging heat generated from the fixing device to the outside of the main body of the device.

[0002]

2. Description of the Related Art In an image forming apparatus such as a laser beam printer for recording an image by an electrophotographic method, a toner image is formed on a sheet fed into the apparatus by a sheet feeding mechanism by an electrophotographic photoreceptor, A fixing device for fixing a toner image on a sheet is usually provided.

As the fixing device, a device for fixing by applying heat and pressure is generally known. For example, it is composed of a fixing roller which is provided with a heater and is heated, a pressure roller which is pressed against the fixing roller, and the like. Then, the paper is sandwiched between the two rollers and the rollers are rotated to perform fixing and paper feeding. The temperature of the heated fixing roller reaches a hundred and several tens of degrees on the surface, and the heat radiated from the fixing roller causes the ambient temperature around the fixing device to rise. In addition to the fixing device, if there are electric circuit parts such as a power source and a light source lamp for illuminating the original, these parts also generate heat and the ambient temperature inside the main body of the apparatus rises.

For this reason, an exhaust device is usually provided in order to release the heat to the outside of the image forming apparatus. Generally, an electric axial fan is provided in the image forming apparatus and the inside of the exterior unit rises through a louver opening. The heated air is exhausted to suppress the temperature rise inside the image forming apparatus.

In the above image forming apparatus, the number of electric fans is kept to a minimum in terms of cost and space, and the heat generated from the fixing device and the heat generated from electric parts such as a power source are reduced to one.
It is common to use an electric fan to exhaust all air. 7A and 7B show a configuration example of the conventional example.
7A is a schematic view of the image forming apparatus viewed from above, FIG.
FIG. 3B is a schematic view of the image forming apparatus as viewed from the side. In FIGS. 7A and 7B, in this image forming apparatus, air is taken in from the fixing device 101, which is the first heat source, and the power source portion 102, such as the drive circuit, which is the second heat source, and is exhausted outside the apparatus. As described above, the electric fan 103 is arranged between the heat sources, and the air passage forming member 104 such as a tact is arranged on the suction side of the electric fan 103 so as to appropriately inhale from the two heat sources. The air passage is set in two directions. As a result, hot air is sucked out in the direction of the arrow in the figure,
Exhaled outside the device.

[0006]

In the above-mentioned conventional image forming apparatus, since the electric fan is arranged between the plural heat sources so that the heat of the plural heat sources is exhausted by the single electric fan, the air passage is bent. However, a loss occurs on the intake side of the electric fan, and the exhaust performance of the electric fan cannot be fully utilized. Therefore, in the vicinity of the fixing device 101 which generates the most heat, FIG.
As shown in (a), in the end portion side a portion of the fixing device which is close to the fan 103 and the other end portion side b which is far from the fan 103, the latter portion b has a higher ambient temperature. Since there is a temperature gradient between the parts, it is difficult to uniformly lower the temperature around the fixing device.

On the other hand, in the prior art, the driving voltage of the electric fan is increased to increase the number of revolutions to increase the exhaust amount, and the temperature gradient is not eliminated, but it is possible to sufficiently cool the portion b, or the number of electric fans is increased. To increase the exhaust performance. However, in the former case, the driving voltage increases, so that the power consumption of the device increases, and in the latter case, there is a problem that the cost for the increased electric fan increases.

Therefore, the number of electric fans is not increased, and at the same time, the driving voltage of the electric fans is not increased, the cost increase is minimized, and the heat exhaustion from the inside of the image forming apparatus is effectively performed without increasing the power consumption. There was a strong desire to do it.

[0009]

An image forming apparatus of the present invention that achieves the above object has a first exhaust member that is electrically driven and a second exhaust member that is driven by a sheet feeding operation in the image forming apparatus. And a member.

[0010]

【Example】

(Embodiment 1) FIGS. 1 and 2 show a first embodiment of the present invention. 1A and 1B, FIG. 1A is a schematic view of the image forming apparatus viewed from above, FIG. 1B is a schematic view of the image forming apparatus viewed from the side, and FIG. It is a perspective view of a part.

In FIG. 1A, 1 is a fixing device, 2 is a power source,
Reference numeral 3 is an electric fan that is a first exhaust member, 4 is an air passage forming member, 7 is a sheet conveying unit, and 8 is a second exhaust member. The electric fan 3 is provided between the fixing device 1 and the power source unit 2 as in the conventional case, and sucks warm air from the respective directions of arrow A and exhausts it to the outside of the device. As shown in FIG. 1B, the transport unit 7 is disposed adjacent to the fixing device 1 and is provided at a position where the sheet that has passed through the fixing device is discharged to the outside of the image forming apparatus. Specifically, as shown in FIG. 2, two side plates 7-1 facing each other, a plurality of rollers 7-2, a conveying roller 7-3 pressed by the side plates 7-3 to convey a sheet, a shaft 7-4 to which each roller is fixed, a shaft A bearing 7-5 for rotatably supporting the side plate 7-4, a gear 7-6 for transmitting the drive from a motor (not shown) to the shaft, and the like,
The fan-shaped second exhaust member 8 is fixed to the shaft 7-4. With this configuration, printing starts and when the transport roller rotates in the direction of arrow R by the drive from the motor to eject the paper in the direction of arrow Y, the second exhaust member 8 also rotates in the same direction as the shaft 7-4 rotates. . Then, the air is sucked in the direction of arrow B in FIG. 1 and the warm air in the image forming apparatus is exhausted to the outside of the apparatus through the louver opening 9-1 provided in the exterior 9.

Therefore, the second exhaust member 8 is connected to the shaft 7 of the conveying roller.
Since the power supply for the second exhaust member 8 does not need to be particularly provided by being fixedly provided at −4, it is possible to improve the heat discharge performance of the image forming apparatus with a simple configuration without increasing power consumption. .

In the present embodiment, at the time of printing when the fixing device has a high temperature, the second exhaust member disposed on the side opposite to the first exhaust member of the fixing device in the longitudinal direction rotates to perform exhaust, which is effective. If the heat can be exhausted and the rotation speed of the transport roller increases, the rotation speed of the second exhaust member also increases. Therefore, if the print speed increases, the exhaust performance also improves, and the print speed is expected to increase in the future. In, it becomes more effective. Further, by providing the heat-exhausting members on both ends of the device that generates heat as in this embodiment, it is possible to eliminate an undesirable temperature gradient in the heat-generating member with a simple configuration.

(Embodiment 2) FIGS. 3 and 4 show a second embodiment of the present invention.
FIG. 3 is a side view of a main part of the image forming apparatus, and FIG. 4 is a perspective view of the same.

In the present embodiment, the position where the second exhaust member is provided is different, and the same members as in the first embodiment will be described with the same numbers.

In FIG. 3, a fixing device 1-1 includes a fixing roller 1-1 including a heater to be heated and a pressure roller 1-2 pressed by the fixing roller, and a sheet is sandwiched between them to heat fixing. Let The fixing roller 1-1 rotates in the direction of arrow S, and its drive is transmitted from below in the figure by a motor and a gear train G (not shown). The gear train G has gears 10, 11,
There are 12, 13, etc., and the gear 13 meshes with a gear (not shown) fixed to the fixing roller. As shown in FIG. 4, the shafts of the respective gears are rotatably supported by the two side plates 14. One end of the shaft portion of the gear 11 is extended from the side plate position, and a fan-shaped second exhaust member 8 is fixed to the tip of the gear 11 as shown in FIG.

When printing is started in this configuration, a motor (not shown) is driven and the gear 11 rotates in the direction of arrow T in FIG. 3, so that the second exhaust member 8 also rotates in the same direction and is provided on the exterior 9. Warm air inside the image forming apparatus is exhausted to the outside of the apparatus through the louver opening 9-1.

Therefore, the second exhaust member is fixedly provided to one arbitrary gear shaft in the gear train for rotating the roller of the fixing device, so that the positional relationship between the paper discharge unit and the fixing device is related. Instead, the second exhaust member can be provided at a desired position near the fixing device.

(Embodiment 3) FIG. 5 shows a third embodiment according to the present invention and is a side view of the main part of an image forming apparatus. Also in this embodiment, the same members as those in the first embodiment will be described with the same reference numerals.

In FIG. 5, the fixing roller 1 of the fixing device 1-
A gear train G is provided to rotate 1 and gears 12,
Each of the gears has a shaft portion rotatably supported by a side plate (not shown). The small gear 18-1 of the step gear 18 is separately engaged with the gear 17, and the gear 19 is engaged with the large gear 18-2. The shaft portion of the gear 19 is extended from the side plate position like the gear 11 of the second embodiment, and the second exhaust member 8 is provided at the tip thereof.

With this configuration, at the time of printing, the gear 19 rotates in the direction of the arrow T by the rotation of the motor (not shown).
The second exhaust member 8 also rotates in the same direction to exhaust warm air inside the image forming apparatus to the outside of the apparatus.

In the present embodiment, the second exhaust member can be rotated at a speed higher than that of the gear 17 by using the stepped gear 18, and the exhaust performance can be improved as compared with the second embodiment.

(Embodiment 4) FIGS. 6 (a) and 6 (b) show a fourth embodiment of the present invention. FIG. 6 (a) is a side view of an essential part of an image forming apparatus, and FIG. FIG. 6B is a diagram showing the swing of the second exhaust member. Also in this embodiment, the same members as those in the first embodiment will be described with the same reference numerals.

In order to transmit the drive of the main motor (not shown) to the fixing roller 1-1 in FIG.
2, 12, 13 and step gear 21 are provided. A swing arm 23 is swingably supported in the direction of arrow U on the shaft around which the gear 22 rotates, and a gear 24 is provided at one end of the swing arm 23.
Is rotatably held. As with the gear 11 of the second embodiment, the gear 24 has a gear 2 extending from the swing arm 23.
The second exhaust member 8 is fixed to the shaft portion of No. 4 and rotates together with the gear 24. A protrusion 23-1 is provided at the other end of the swing arm 23, and a solenoid 25 fixed to the image forming apparatus main body is freely connected to the protrusion 23-1. Further, a coil spring 26 is locked to the protrusion 23-1, and the other end of the coil spring is locked to a fixed shaft on which the step gear 21 rotates. And the fixing roller 1 of the fixing device 1
1 is controlled so as to switch to a plurality of types of temperatures so that optimum fixing is performed according to the paper size and the like.

With the above configuration, the main motor is the fixing roller 1
When -1 is driven to rotate in the direction of arrow S, each gear also rotates in a predetermined direction. The swing arm 23 is swung in the direction of the gear 12 by the coil spring 26 on the side holding the gear 24, and the gear 24 meshes with the gear 12 and rotates in the direction of arrow T. The fan-shaped second exhaust member provided integrally also performs the exhaust operation by rotating in the same direction. And when raising the fixing temperature according to the change of paper size,
The solenoid 25 operates to swing the swinging arm 23 in the direction of arrow V as shown in FIG. 6B, and switches the gear 24 from meshing with the gear 12 to meshing with the stage gear 21.
The stepped gear 21 includes a small gear portion 21-1 and a large gear portion 21-2 that transmit the rotation of the gear 20 to the gear 22, and the gear 24 meshes with the large gear portion 21-2 to rotate the second exhaust member at a rotational speed. Goes up.

Therefore, in this embodiment, the gear engaged with the gear attached to the second exhaust member 8 is switched in accordance with the switching of the fixing temperature, so that even if the fixing temperature rises, the rotation speed of the second exhaust member is increased to exhaust the exhaust gas. The performance can be improved, and the exhaust can be performed more effectively according to the fixing temperature.

In this embodiment, the fan-shaped second exhaust member has two
Although the configuration is such that the rotation speed is switched to one of the types, there may be more switching steps depending on the fixing temperature. Further, the switching means uses the coil spring and the solenoid, but the specific means is not limited to this.
It goes without saying that another configuration such as a cam may be used as long as the same operation can be performed.

The shape of the second exhaust member may be a cylindrical fan in addition to the rotary blade as in the embodiment. The second exhaust member may be attached to the support roller shaft of the conveyor belt or the like in addition to the rotation shaft of the conveyor roller.

[0029]

As described above, according to the present invention, it is not necessary to use the first exhaust member that is electrically driven and the motor dedicated to the exhaust member that rotates as the paper is fed in the image forming apparatus. By providing the driven second exhaust member, it is not necessary to increase the number of electric fans that require a power source.

Further, heat can be effectively removed from the inside of the image forming apparatus with a simple structure without raising the drive voltage for the electric fan. In other words, keep costs up to a minimum,
The exhaust heat performance can be significantly improved without increasing the power consumption.

[Brief description of drawings]

FIG. 1A is a schematic view of an image reading apparatus according to a first embodiment of the present invention viewed from above. FIG. 3B is a schematic view of the image reading apparatus as viewed from the side.

FIG. 2 is a perspective view of a paper discharge unit according to the first embodiment of the present invention.

FIG. 3 is a side view of a main part of the second embodiment of the present invention.

FIG. 4 is a perspective view of a main part of a second embodiment of the present invention.

FIG. 5 is a side view of the essential parts of Embodiment 3 of the present invention.

FIG. 6A is a side view of essential parts of Embodiment 4 of the present invention.
(B) The figure which showed the rocking | fluctuation of a 2nd exhaust member.

FIG. 7A is a schematic view of a conventional image reading apparatus viewed from above. FIG. 3B is a schematic view of the image reading apparatus as viewed from the side.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1, 101 Fixing device 2, 102 Power supply part 3, 103 Electric fan 4, 104 Air path forming member 5, 105 Paper cassette 6, 106 Paper conveyance path 7 Paper discharge part 8 Second exhaust member 9 Exterior 10, 11, 12 , 13, 15, 16, 17, 19, 2
0, 22, 24 Gear 14 Side plate 18, 21 Step gear 23 Swing arm 25 Solenoid 26 Coil spring

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G03G 15/20 109

Claims (4)

[Claims] 1. An image forming apparatus comprising: a fixing device for melting a toner image formed on a sheet by electrophotography by heat to fix the toner image on the sheet; and an exhaust member for discharging heat generated by the fixing device to the outside. In the apparatus, the exhaust member includes a first exhaust member that is electrically driven and a second exhaust member that is driven by a motor for carrying a sheet in the image forming apparatus. Fixing device. 2. The image forming apparatus according to claim 1, wherein the second exhaust member is a fan member and is fixed to an end portion of a rotary shaft to which a roller for carrying a sheet is fixed. 3. The image forming apparatus according to claim 1, wherein the second exhaust member is a fan member fixed to a gear driven by the motor. 4. An image forming apparatus in which the second exhaust member according to claim 2 or 3 is switched to at least two types of rotation speeds.