JPH02300771A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To provide additionally a suction fan with function to exhaust heat to efficiently exhaust the heat of a fixing device to outside of a machine by exhausting the heat of the suction fan for transfer paper conveyance through above the casing of the fixing device. CONSTITUTION:An air discharge duct 14 is guided to the side of the fixing device 15 along by and above a fixation cover 19 as the casing of the fixing device 15 and its end part is open to the side of a paper discharge tray 16. When air which is sucked by the suction fan 18 through the opening 14b is discharged to outside the machine through the air discharge duct 14, the heat which is generated in the fixing device 15 and exhausted to the air discharge duct 14 from a fixation frame 20 and the fixation cover 19 is carried out of the machine. Thus, the heat which is generated in the fixing device is exhausted efficiently to outside.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for transferring the toner image onto the lower surface side of the fed transfer material by a transfer means at a transfer position on the upper part of the image carrier on which the toner image has been formed. The upper surface of the transfer material after transfer is conveyed to a fixing device while adsorbing it with a suction fan via a guide member, and the fixing device heats and fixes the toner image onto the transfer material to form an image. The present invention relates to an electrophotographic device such as a printer, which forms images.

Conventional technology In an electrophotographic device such as a printer, an optical writing unit 1- is installed at the bottom of the main body to expose the photoreceptor from the bottom to form an electrostatic latent image on the photoreceptor, and after this is developed. There is a type in which the toner image is transferred onto a fed transfer paper at a transfer position above the photoreceptor, and the transfer paper with the toner image transferred thereto is sent to a fixing device to heat and fix the toner image to form an image.

In such a device, since an unfixed toner image is formed on the lower side of the transfer paper, it is not possible to guide the lower side of the transfer paper after transfer with a guide plate or the like to convey it to the fixing device. The transfer paper is conveyed while being sucked from both sides by a suction fan via a guide member having a guide member.

In this case, in the conventional apparatus, the exhaust air from the suction fan is discharged to the outside by providing a dedicated duct without passing through the upper part of the fixing device. In addition, the configuration was such that the flow of air could not be regulated unless such a duct was provided. For this reason, it has not been possible to make the suction fan also have the function of cooling the fixing device, or to use the cover of the fixing device as part of a duct.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and to provide an electrophotographic apparatus that can efficiently discharge heat from a fixing device to the outside of the apparatus.

Means for Solving the Problems In order to solve the above problems, the present invention has a method of transferring the toner image onto the lower surface side of the fed transfer material by means of a transfer means at a transfer position on the upper part of the image carrier on which the toner image has been formed. After transferring, the -L side of the transfer material is conveyed through a guide member to a fixing device while being adsorbed by a suction fan, and the fixing device heats and fixes the toner image onto the transfer material to form an image. The electrophotographic apparatus is characterized in that exhaust air from the suction fan is discharged through a casing of the fixing device.

According to the present invention, the exhaust air from the suction fan for conveying the transfer paper is discharged through the upper part of the fixing device casing, so the suction fan can also have the function of cooling the fixing device, and the heat in the fixing section can be reduced. can be efficiently discharged outside the machine.

An Example of Suetane FIG. 1 is a front view showing the schematic structure of a laser beam printer, which is an example of an electrophotographic apparatus to which the present invention is applied.

First, the entire device will be explained.

On the circumferential surface of the photosensitive drum 10, which is an example of an image carrier, a charger 2, a developing unit 3,
A transfer charger 4 as a transfer means and a cleaning unit 5 are arranged, and a writing optical unit is arranged so that a writing beam enters and exposes the photosensitive drum 1 at a writing position 6 between the charger 2 and the developing unit 3. 7 is provided.

The charger 2 and the writing position W6 are arranged below the photoreceptor drum 1, and the optical writing unit 7 is provided below the photoreceptor tram 1, the i-image unit 3, the cleaning unit 5, and the like. Further, the transfer charger 4 is arranged above the photosensitive drum 1. Paper feed cassette 8 is optical writing unit 7
It is provided further below.

The photosensitive drum 1 is charged by the charger 2 and the writing optical unit 7.
The electrostatic latent image formed thereon is developed by the developing unit 3 and formed as a toner image.

On the other hand, transfer paper, which is an example of a transfer material, is fed out one by one by the feed rollers 9 and corner claws 10 of the paper feed cassette 8, and further sent above the developing unit 3 by an intermediate roller pair 11, and then transferred to the registration roller pair. 12, the toner image formed on the photoreceptor drum 1 is fed to the transfer section at a timing such that the toner image is aligned with the toner image formed on the photoreceptor drum 1, and the toner image is transferred thereon by the transfer charger 4 at the transfer position 4a.

A static elimination brush 13 is provided on the transfer paper path after transfer, and the transfer paper is separated from the photosensitive drum 1 and further conveyed to the fixing device 15 while being guided by a guide portion 14a that is a part of the exhaust duct 14, which is a guide member. Ru. The fixing device heats and fixes the toner image on the transfer paper using a fixing roller 15a having a heat source to complete the image, and discharges the transfer paper to a paper discharge tray 16 provided on the discharge side thereof.

On the other hand, the toner remaining on the photoreceptor drum 1 after transfer is cleaned by the cleaning unit 5, and the charge on the photoreceptor drum 1 is removed by the static eliminator 17, and the toner is prepared for the next image forming process.

Next, the characteristic parts of this device will be explained.

The transfer paper guide portion 14a of the exhaust duct 14 is provided with an appropriate opening 14b for sucking the transfer paper, and the transfer paper is moved to the opening 14b by a suction fan 18 installed at the top.
While being sucked through the image forming apparatus, it is guided by the guide section 14a and conveyed to the fixing section M15. This exhaust duct 14 is guided toward the fixing bag M15 side along the side and top portions of a fixing cover 19, which is a casing of the fixing device 15, and its end is open toward the paper discharge tray 16 side.

With this configuration, the suction fan can reduce the opening 11 in one day.
The air sucked through b is discharged outside the machine through the exhaust duct 14, but at this time, the heat generated inside the fixing device 15 and transferred from the fixing frame 20 and fixing cover 19 to the exhaust duct 14 is removed. is carried out of the aircraft by this air flow. As a result, the heat generated from the fixing device 15 can be efficiently discharged to the outside of the apparatus by using the suction fan 18 provided for conveying the transfer paper. In this way, removing excess heat from the fixing device 15 and preventing heat dissipation into the machine prevents an increase in the ambient temperature of parts such as LDs installed in the machine where a rise in ambient temperature is undesirable. It can also be used as an auxiliary tool.

Note that by providing such a duct, the suction fan 18 can be operated efficiently by regulating the flow of exhaust gas from the suction fan I8.

FIG. 2 shows another embodiment. In this embodiment, the exhaust duct 14 is an independent duct and is stopped at a portion c of the exhaust duct 14, and the fixing cover 19 also functions as an exhaust duct. In this way, heat is removed directly from the fixing cover 19 without going through the exhaust duct 14 shown in FIG. Furthermore, the efficiency of the suction fan 18 can be improved by increasing the width of the duct in the vertical direction, increasing the cross-sectional area, and increasing the size of the duct.

Effects As described above, according to the present invention, by discharging the exhaust air from the suction fan for conveying the transfer paper through the casing of the fixing device, the suction fan also serves as a heat exhaust function, and the heat of the fixing device is efficiently transferred to the outside of the machine. can be taken away.

[Brief explanation of the drawing]

1 and 2 are schematic front views of a laser beam printer according to an embodiment of the present invention. 1... Photosensitive drum (image carrier) 4...
- Transfer charger (transfer means) 4a... Transfer position 14... Exhaust duct 14a, - Guide section (guide member) 15... Fixing device 18... Suction fan

Claims (1)

[Scope of Claims] At a transfer position on the upper part of the image carrier on which the toner image has been formed, the toner image is transferred by a transfer means to the lower surface side of the fed transfer material, and the toner image is transferred to the upper surface side of the transfer material after transfer. In an electrophotographic apparatus, the toner image is conveyed through a guide member to a fixing device while being adsorbed by a suction fan, and the fixing device heats and fixes the toner image onto the transfer material to form an image. An electrophotographic apparatus characterized in that the image is discharged through a casing of the fixing device.