JPS63266466A - Air discharger of image forming device - Google Patents

Abstract

PURPOSE:To enhance the cooling effect around an image carrier by providing partitions which are so formed that the sections thereof decrease toward the inner side of a paper discharge cover between vent ports. CONSTITUTION:An exhaust fan 11 provided in a housing 12 takes in air from the vent port, not shown, on a base 12a and generates air flow in the direction of an arrow A toward the vent port 32 of the paper discharge cover 30 via the part near a photosensitive drum 13. The many vent ports 32 partitioned by the partitions 31 are formed to the paper discharge cover 30. These partitions 31 are so formed that the sections thereof decrease gradually from the outer side toward the inner side of the paper discharge cover 30. The air heated in an image forming stage is thereby forcibly discharged from the side face of the housing 12 without being hindered in the air flow through the vent ports 32. As a result, the air around the drum 13 circulates smoothly and the temp. rise of the drum 13 is surely prevented.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to an improvement in an exhaust system in an image forming apparatus such as an electrophotographic apparatus for preventing temperature rise around an image bearing member of the image forming apparatus. .

(Prior Art) In image forming apparatuses such as electrophotographic apparatuses and printers that form an electrostatic latent image on an image carrier to obtain an image.

The characteristics of the image carrier vary significantly due to the temperature increase, which causes blurring and blurring of the image. For this reason, in an apparatus using a fixing device having a heating section such as a heat roller, it is necessary to prevent the temperature rise of the surrounding area due to the fixing device and the temperature rise of the image carrier. A device as shown in FIG. 5 is commonly used.

That is, in this device, a cylindrical exhaust fan (11) is provided above the heat roller (1o), and by driving this,
An airflow in the direction of arrow A is generated within the casing (12), and the casing (
12) While taking in fresh air from the bottom surface (12a) toward the photoreceptor drum (13) as an image carrier, the heated air around the photoreceptor drum (13) and above the heat roller (1o) is transferred to the housing ( 12) side paper ejection cover (1
2b) is forcibly discharged to the outside through a vent hole (14) formed in the hole.

However, in such devices, the thickness of approximately 2 (
Paper ejection cover (mm) made of integrally molded plastic
12b) and a large number of vent holes (14) formed in the vent hole (12b).
As shown in FIG. 5, the width of the partition (16) provided between the sheets (14) and 14) is constant at about 3 (nun) from the inside to the outside of the paper discharge cover (12b). Therefore, during exhaustion, the airflow generated by driving the exhaust fan (11) hits the partition (16) and is blocked, reducing the exhaust efficiency.

For this reason, if a large number of continuous copies are made, 200
('C) Hot air around the fixing device (17), which is heated back and forth, gradually stagnates around the photoreceptor drum (13).

The temperature of the photoreceptor drum (13) increases, which in turn causes variations in characteristics, and if the image forming process is continued as it is, one image becomes blurry and blurred, resulting in a significant deterioration in image quality.

(Problems to be Solved by the Invention) Conventionally, regardless of the drive of the exhaust fan, the exhaust efficiency at the ventilation port of the paper ejection cover was poor, and when continuous copying etc. were performed, the temperature of the image carrier increased and the image It has the disadvantages of being cluttered and deteriorating the image quality.

SUMMARY OF THE INVENTION Therefore, the present invention aims to eliminate the above-mentioned drawbacks, and provides an image forming apparatus that can improve the exhaust efficiency at the vent, prevent the temperature of the image carrier from rising, and always obtain clear and high-quality images. shall be.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a partition between the ventilation holes, the cross section of which becomes narrower toward the inside of the paper ejection cover. By providing this, the inside of the vent, which is the intake port for airflow, is expanded.

(Function) According to the present invention, by using the above-mentioned means, it is possible to smoothly exhaust the air through the vent and prevent a rise in temperature within the housing, thereby preventing fluctuations in the characteristics of the image carrier and obtaining a good image. .

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. The same parts as those of the conventional device are given the same reference numerals, and the explanation thereof will be omitted.

A main charger (18) and an erasing array (20
), a first developing device (21), a second developing device (22), a transfer charger (23), a peeling charger (24), a cleaner (26), and a static eliminator (27). On the other hand, an exhaust fan (11) is provided above the fixing device (28) having a heat roller (28a) and a press roller (28b) for forcibly exhausting the air inside the housing (12).
Due to this drive, inside the casing (12), the bottom surface (12
External air is taken in through the vent hole (not shown) formed in a), passes near the photoreceptor drum (13), and heads toward the vent hole (32) of the exhaust cover (30) as shown in the direction of arrow A. Air bubbles are generated. In addition, there is a partition (31) on the paper ejection cover (30) made of plastic on the side of the housing (12).
) are formed, and the cross section of these partitions (31) is similar to that of the paper ejection cover (
30), the width is approximately 3 (mm) on the outside, while it gradually becomes narrower towards the inside, and the width on the inside is approximately 0.5 (mm). There is.

Note that (32) is an exposure device, (33) is a paper feed device, and (34) is an exposure device.
) is the upper paper feed cassette, (36) is the lower paper feed cassette, (37) is the document holder, and (38) is the paper output tray.

Next, we will discuss the operation. First, by turning on the main switch (not shown), each device is made ready for image formation.
The heat roller (28a) is heated and the exhaust fan (11) is driven. Next, when image formation is started by turning on a print switch (not shown), the photosensitive drum (13) is rotated in the direction of arrow The toner image is transferred by the transfer charger (23) onto a sheet of paper (not shown) fed, for example, from the upper paper feed cassette (34), and then the sheet of paper is transferred to the fixing device ( 28), the paper is discharged onto a paper discharge tray (38).

Furthermore, after the transfer is completed, the photosensitive drum (13) is cleaned.

After each step of static elimination, the next image can be formed.

On the other hand, during such an image forming process, the exhaust fan (11) is constantly driven, and the airflow generated by the exhaust fan (11) in the six directions of the arrows causes the heated air around the photoreceptor drum (13) to be taken in. The ventilation hole (32) is widened on the inside of the paper ejection cover (30) so that the opening is wider.
The airflow is forcibly discharged from the side of the casing (12) without being blocked. Along with this, the bottom surface (12a) of the casing (12) is always placed around the photoreceptor drum (13).
External cold air is supplied through the In this way, the image forming process is repeated while exhausting air using the exhaust fan (11), and after all necessary images are completed,
Turn off the main switch (not shown) and turn off the heat roller (
The heating of 28a) and the drive of the exhaust fan (11) are stopped, and all image formation is completed.

With this configuration, a large number of vents (32) and vents (
The shape of the partition (31) between the exhaust fan (1
1) is formed to reduce the resistance force against the airflow in the six directions of the arrows, and the airflow is efficiently discharged without being blocked or stagnated at the vent (32). A rise in air temperature around the drum (13) is prevented. Therefore, even during continuous copying, the temperature of the photoreceptor drum (13) does not rise, its characteristics are maintained well, and deterioration in image quality due to blurring or blurring can be prevented, resulting in clear and high-quality images. I can do things.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways.1 For example, the paper ejection cover may be made of any material, and the partitions may be formed to become narrower toward the inside of the paper ejection cover. For example, the width and other sizes are not limited.

Furthermore, the shape of the partition may be chamfered or streamlined to further reduce resistance to airflow.

Note that the slits of the first ventilation port may be horizontally long, and further, the shape of the ventilation port may be grid-like.

〔Effect of the invention〕

As explained above, according to the present invention, the airflow generated by the exhaust fan is not blocked by the partition of the vent,
Because it is efficiently discharged, the air heated by the fixing device, etc. does not stagnate around the image carrier, and the air around the image carrier is circulated smoothly, ensuring that the temperature of the image carrier increases. In addition, the characteristics of the image carrier are not deteriorated, and a clear and high-quality image can be obtained.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, and FIG. 1 is an explanatory diagram showing the entire image forming apparatus. Fig. 2 is a partial perspective view of the case seen from the side, Fig. 3 is a partial sectional view showing the vent, and Figs. 4 and 5 show the conventional device, and Fig. 4 is the image forming device. FIG. 5 is a partial sectional view showing the vent. DESCRIPTION OF SYMBOLS 12... Housing, 13... Photosensitive drum, 28... Fixing device, 30... Paper discharge cover, 31... Partition, 32.
··vent.

Claims (2)

[Claims] (1) In a device that uses an exhaust fan to generate airflow from the inside of a casing containing an image carrier toward a large number of vents separated by partitions, the vents widen as they go inside the casing. An exhaust device for an image forming apparatus characterized by having a cross-sectional shape as shown in FIG. (2) The exhaust device in the image forming apparatus according to claim 1, wherein the airflow by the exhaust fan is directed from the vicinity of the image carrier toward the vent.