JPH086465A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To prevent the heat generated in a fixing device from being transmitted to a photoreceptor or a developing device and to prevent the fixing device from being excessively cooled by forming a ventilation path on an upstream side in the carrying direction of a printing paper and at a position where it is faced to the heat generation part of the fixing device and forming a heat storage part on a downstream side in the carrying direction of the printing paper and at a position where it is faced to the heat generation part of the fixing device. CONSTITUTION:The ventilation path 24 is formed on the upstream side in the carrying direction of the printing paper 23 and at the position where it is faced to the heat generation part 18 of the fixing device 11. The path 26 is constituted so as to be slender in a main scanning direction and made to communicate with an exhaust port formed on the left side plate of a lower housing 4. An exhaust unit is arranged at the exhaust port. Besides, the heat storage part 26 is formed on the downstream side in the carrying direction of the paper 23 and at the position where it is faced to the heat generation part 18 of the fixing device 11. Therefore, the heat generated by the fixing part 11 is not transmitted to an electrophotographic unit 10 by the path 24. By the heat stored at the storage part 26, the fixing device 11 is prevented from being excessively cooled caused by the forcible exhaust of the path 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus for forming an image on printing paper by electrophotography.

[0002]

2. Description of the Related Art Electrophotographic devices such as laser printers are
A photoconductor such as a photoconductor drum is rotatably provided, and a charging device, an exposing device, a developing device, and a transferring device are sequentially arranged at positions facing the surface of the photoconductor. A transport path for the printing paper is formed in the gap between the transfer device and the photoconductor, and a fixing device is arranged on the downstream side of the photoconductor on the transport path for the print paper.

Therefore, in such an electrophotographic apparatus, the surface of a photoreceptor which is successively rolled is charged by a charging device and then exposed by an exposing device to form an electrostatic latent image. The electrostatic latent image is developed with toner supplied from the developing device and transferred to printing paper by the electric field of the transfer device. Then, the printing paper on which the toner image is transferred is heated and pressed by the fixing device, so that the toner image is fixed on the printing paper and the image printing is completed.

However, since such a fixing device generates a great amount of heat, if the fixing device accumulates in the main body of the electrophotographic apparatus and the photoconductor and the developing device are excessively heated, the photoconductor and the toner are deteriorated. Therefore, in a general electrophotographic apparatus, an exhaust device is provided inside the opening formed in the main body housing, and the hot air generated by the fixing device is forcibly discharged to the outside of the device by the exhaust device, so that the photoconductor It prevents the vessel from overheating.

[0005]

In the electrophotographic apparatus as described above, the toner image formed on the printing paper by the electrophotographic method is heated and fixed by the fixing device, and the hot air of the fixing device is discharged to the outside of the device. It protects the photoconductor and the developing device.

However, at present, there is a demand for downsizing of the electrophotographic apparatus, and in order to realize this downsizing, the respective parts are arranged in high density. In this case, the heat generated by the fixing device is satisfactorily transmitted to the photoconductor and the developing device, and the ventilation of air is also hindered, so that it is difficult to satisfactorily discharge the hot air inside the main body to the outside of the device.

[0007] For example, in order to solve the above-mentioned problems, it is possible to envisage providing a powerful exhaust device.
If the inside of the main body of the electrophotographic apparatus is excessively cooled, the temperature of the fixing device is lowered, the fixing performance is deteriorated, and the power consumption is increased.

[0008]

At least a charging device, an exposing device, a developing device and a transfer device are sequentially arranged at a position facing a surface of a rollable photoconductor, and a gap between the transfer device and the photoconductor is provided. In an electrophotographic apparatus in which a conveyance path for the printing paper is formed on the printing paper conveyance path and a fixing device is arranged on the downstream side of the photoconductor on the conveyance path of the printing paper, the heat generating portion of the fixing device is provided on the upstream side in the conveyance direction of the printing paper. An air passage was formed at a position facing the heat generating part of the fixing device on the downstream side in the transport direction of the printing paper.

[0009]

With the ventilation passage facing the heat generating portion of the fixing device on the upstream side in the conveying direction of the printing paper, the hot air generated by the fixing device is exhausted to prevent the photoconductor and the developing device from being heated. By the heat storage section facing the heat generating section of the fixing device on the downstream side of
The heat generated by the fuser is accumulated to prevent the fuser from being excessively cooled.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the directions such as front and rear and up and down in the present embodiment are defined for convenience in order to simplify the description, and this does not limit the actual installation or use direction of the device.

First, in the laser printer 1 which is this electrophotographic apparatus, as shown in FIG. 1, a flat box-shaped main body housing 2 is formed of an upper housing 3 and a lower housing 4, and the upper portion A paper feed port 5 is formed in the rear portion of the upper surface of the housing 3, and a paper discharge port 6 is formed in the upper portion of the front surface. Inside the main body housing 2, there is formed a paper transport path 7 that communicates from the paper feed port 5 to the paper discharge port 6. On the paper transport path 7, a separation paper feed mechanism 8 and A pair of conveyance rollers 9, an electrophotographic unit 10, a fixing device 11, and a pair of paper discharge rollers 1.
2 and are sequentially arranged.

The electrophotographic unit 10 is a photosensitive drum 1 which is a cylindrical photosensitive member rotatably supported.
3, a charging blade 14 which is a charging device, a laser scanner 15 which is an exposing device, a developing device 16, and a transfer roller 17 which is a transferring device are sequentially arranged on the surface of the fixing device 3. Reference numeral 11 has a structure in which a heat roller 19 that is rotatable and generates heat inside a main body case 18 and a rotatable press roller 20 are pressed against each other. In the fixing device 11, the heat roller 19 is connected to the paper transport path 7
It is located below the main body case 1 here.
The lower half part of 8 is a heat generating part.

Therefore, as illustrated in FIG. 1 and FIG.
On the front upper surface of the bottom plate of the lower housing 4, a guide plate 21 that abuts the lower surface of the main body case 18 of the fixing device 11 and a guide plate 22 that opposes the rear surface thereof are provided in a protruding manner. , 22 to the fixing device 1 on the upstream side in the transport direction of the printing paper 23.
An air passage 24 is formed to face the first heat generating portion. Here, as illustrated in FIG. 2, the ventilation passage 24 is formed to be elongated in the main scanning direction and communicates with an exhaust port 25 formed in the left side plate of the lower housing 4, and the exhaust port An exhaust unit (not shown) in which an exhaust fan is rotatably supported by a drive motor is arranged at a position facing 25.

Further, due to the gap between the guide plate 21 and the rear surface of the front plate of the lower housing 4, the printing paper 23 is formed.
A heat storage section 26 facing the heat generating section of the fixing device 11 is formed on the downstream side in the transport direction of the above.

In the laser printer 1 having such a structure, the electrophotographic unit 10 forms a toner image on the printing paper 23 which is inserted from the paper feed port 5 into the paper carrying path 7 and separated and fed by the separating and feeding mechanism 8. (Not shown) is transferred, and the toner image is heat-pressed by the fixing device 11 to be fixed on the printing paper 23. At this time, this fixing device 11
Since the heat roller 19 that presses the printing paper 23 against the press roller 20 generates heat, the heat generated by the heat roller 19 is dissipated from the surface of the lower half of the main body case 18.

However, in the laser printer 1, since the ventilation passage 24 is located in the gap between the fixing device 11 and the electrophotographic unit 10, the heat generated by the fixing device 11 is not transmitted to the electrophotographic unit 10. The deterioration of the photosensitive drum 13 and the developing device 16 of the electrophotographic unit 10 due to excessive heating is prevented.

Moreover, in the laser printer 1, since the heat storage portion 26 is formed at the position opposite to the fixing device 11 on the side opposite to the electrophotographic unit 10, the fixing device 11 is generated inside the heat storage portion 26. It keeps the high temperature by accumulating hot air. Therefore, excessive heat of the fixing device 11 due to forced exhaust of the ventilation passage 24 is prevented by the heat storage of the heat storage unit 26, and deterioration of the fixing performance and increase of power consumption are prevented.

In this embodiment, as the fixing device 11, the heat roller 19 and the press roller 20 are in pressure contact with each other, but the present invention is not limited to the above embodiment. It is also possible to form the fixing device in a form in which a press roller is pressed against a stationary heater panel, or in a form in which a heat generating lamp and a light collecting panel are combined (both not shown).

In this embodiment, the heat storage section 26 is used as a simple space to improve productivity with a simple structure. However, the present invention is not limited to the above embodiment. It is also possible to fill the heat storage unit 26 with a heat storage material (not shown) to improve the heat storage performance.

Further, in the present embodiment, the cooling performance of the electrophotographic unit 10 is improved by disposing the exhaust device at a position communicating with the ventilation passage 24, but the present invention is limited to the above embodiment. For example, it is also possible to form such an air passage in a form that communicates in the vertical direction and to let the air flow by natural convection.

[0021]

As described above, according to the present invention, at least a charging device, an exposing device, a developing device, and a transferring device are sequentially arranged at a position facing the surface of a freely rotatable photosensitive member. In an electrophotographic apparatus in which a conveyance path for printing paper is formed in a gap between the body and a fixing device is arranged downstream of the photoconductor on the conveyance path for printing paper, the fixing is performed on the upstream side in the conveyance direction of the printing paper. An air passage is formed at a position facing the heat generating part of the fixing device, and a heat storage part is formed at a position facing the heat generating part of the fixing device on the downstream side in the transport direction of the printing paper, so that the heat generated by the fixing device is exposed. Since the air can be prevented from being transmitted to the body and the developing device, deterioration of the photoconductor and the toner can be prevented, and moreover, excessive cooling of the fixing device can be prevented by the heat storage section. As a result, fixing performance may deteriorate and power consumption may increase. Those having an effect such as can be stopped.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view illustrating the internal structure of a laser printer that is an embodiment of the electrophotographic apparatus of the present invention.

FIG. 2 is a plan view illustrating a lower housing of the laser printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic device 7 Conveyance path 11 Fixing device 13 Photoconductor 14 Charging device 15 Exposure device 16 Developing device 17 Transfer device 18 Heating part 24 Ventilation path 26 Heat storage part

Claims (1)

[Claims] 1. A charging device, an exposing device, a developing device, and a transfer device are sequentially arranged at a position facing a surface of a rotatable photoconductor, and a printing paper is placed in a gap between the transfer device and the photoconductor. In an electrophotographic apparatus in which a transport path is formed and a fixing device is arranged on the downstream side of the photoconductor on the transport path of the printing paper, a position facing the heat generating part of the fixing device on the upstream side in the transport direction of the printing paper. An electrophotographic apparatus, characterized in that a ventilation path is formed in the sheet, and a heat storage section is formed at a position facing the heat generating section of the fixing device on the downstream side in the transport direction of the printing paper.