JPH06242653A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device capable of efficiently and securely exhausting ozone and hot air without requiring an exhaust fan motor with a large capacity and with a single exhaust fan. CONSTITUTION:A duct guiding ozone-containing air and hot air generated during image formation, to the exhaust fan 30 side is divided into two sections of a first duct 37 and a second duct 40. An ozone removal filter 38 is fitted only in the exit of the first duct 37 through which the ozone-containing air passes, that is, a first outlet 34. Therefore, because the ozone removal filter 38 is not fitted in a second outlet 35, the hot air efficiently flows out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image on a sheet by using a process unit including a photoconductor and a heat fixing device.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus of this type, a photosensitive drum is uniformly charged by a charging device of a process unit, and an electrostatic latent image is formed on the photosensitive drum by an exposing device. Then, toner is attached to the electrostatic latent image by the developing device, and the toner is transferred onto the paper by the transfer device. After that, the toner image transferred onto the paper is heat-fixed by the heat fixing device.

Further, in this type of image forming apparatus, corona discharge is carried out at the time of charging of the charger, but harmful ozone is generated along with the corona discharge. Further, since the heat fixing device is maintained in a high temperature state by energization, the heat causes the temperature of the air around the heat fixing device and the process unit to become high.
Therefore, the image forming apparatus is provided with an exhaust fan for discharging the ozone and high temperature air to the outside. When discharging ozone, it is necessary to make the ozone harmless to the human body and other devices through an ozone removing filter. By the way, the high temperature air thermally expands the photosensitive drum and the like to make the gap between the photosensitive drum and peripheral devices unstable, which adversely affects the image quality.

By the way, when the charging device and the heat fixing device are arranged vertically apart from each other, if ozone or high temperature air generated from each device is surely discharged,
It is necessary to install exhaust fans at the upper and lower positions corresponding to each device. Therefore, a plurality of exhaust fans are required, the number of parts is increased, and the manufacturing cost is increased.

[0005]

Therefore, it is conceivable that one large exhaust fan is opposed to both the ozone generator and the fixing device so that ozone and high temperature air are exhausted by one exhaust fan.

In this case, the high temperature air which does not require the ozone removing filter passes through the ozone removing filter, so that the discharge resistance of the high temperature air becomes large. As a result, the exhaust efficiency of the high-temperature air may decrease, the temperature inside the device case may increase, and the print image quality may deteriorate.

In order to solve this problem, a method of using a large capacity motor for the exhaust fan can be considered. However, in this case, since power consumption is improved, not only problems in terms of cost and economical efficiency but also problems of noise occur.

The present invention has been made in order to solve the above problems, and an object of the present invention is to efficiently use ozone and high-temperature air with one exhaust fan without using the exhaust fan motor as a large-capacity motor. An object of the present invention is to provide an image forming apparatus that can reliably and reliably discharge the image.

[0009]

In order to achieve the above object, according to the present invention, an image forming apparatus for forming an image on a sheet by a process unit in an apparatus case and a heat fixing device is provided in the apparatus case. An exhaust fan for discharging the air in the device case to the outside is provided, and the suction side of the exhaust fan is divided into a first passage through which ozone-containing air passes and a second passage through which ozone-free air passes, The gist of the invention is that an ozone removing filter is provided at the outlet of the first passage.

[0010]

According to the structure of the present invention, when the image forming operation is started, the toner image is formed on the sheet based on the charging of the photoconductor. After that, the toner image is thermally fixed on the paper by the heat fixing device. At this time, ozone is generated in the device case as the peripheral surface of the photoconductor is charged, and
High temperature air is generated by the heat generated by the heat fixing device.

The ozone-containing air containing ozone generated by the photoconductor is firstly attracted by the suction force of the exhaust fan.
After passing through the ozone removal filter from the passage to remove ozone, the ozone is discharged to the outside of the device case. Further, the high-temperature air containing no ozone generated from the heat fixing device is discharged from the second passage to the outside of the device case by the suction force of the exhaust fan. At this time, since the ozone removing filter is not provided between the second passage and the exhaust fan, the high temperature air is smoothly discharged to the outside of the device case.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the device case 1 is formed in a substantially box shape having an upper surface opened, and a lid body 2 is supported by a support shaft 3 in the upper surface opening portion so as to be openable and closable.
A photosensitive drum 4 as a photosensitive member for forming an image is rotatably supported in the apparatus case 1, and a photoconductive film 5 is formed on the outer peripheral surface thereof. The charger 6 is arranged to face the outer periphery of the upper portion of the photosensitive drum 4, and uniformly charges the photoconductive film 5 to a predetermined potential. The charger 6 has a discharge wire 7 shown in FIG. 2, and corona discharge is performed by energizing the discharge wire 7 to uniformly charge the photoconductive film 5 to a predetermined potential. The exposure device 8 forms an electrostatic latent image of a predetermined potential on the photosensitive drum 4 by irradiating light.

The developing device 9 includes a toner case 10 for containing the toner T, a toner cartridge 11 detachably mounted on the toner case 10, and a photosensitive drum 4.
And a developing roller 12 disposed at the lower end opening in the toner case 10 so as to closely face it. A predetermined potential is applied to the toner T by the developing roller 12, and the toner T is attached to the electrostatic latent image based on the difference between the potential and the potential of the electrostatic latent image to visualize the electrostatic latent image. To be done.

The paper cassette 13 contains a large number of recording papers P in a stacked state. Then, the feeding-side end of the recording paper P is pressed against the outer peripheral surface of the lower portion of the paper feed roller 15 via the push-up plate 14 by a spring (not shown). Then, the paper feeding roller 15 is rotated to cause the paper cassette 13 to rotate.
The recording papers P are fed one by one from the inside, and the recording papers P are transported to the lower part of the photosensitive drum 4 via a paper guide 16 and a pair of feed rollers 17.

The transfer device 18 and the guide roller 19 are arranged so as to face the outer periphery of the lower portion of the photosensitive drum 4 with the sheet transfer path interposed therebetween. Then, the recording paper P is brought into close contact with the photosensitive drum 4 by the guide roller 19, and a predetermined potential is applied to the close contact portion by the transfer device 18, and based on the difference between the potential and the potential of the toner image, The toner image is transferred onto the recording paper P.

The static elimination lamp 20 exposes the outer peripheral surface of the photosensitive drum 4 after the transfer to eliminate static electricity. The cleaning brush 21 removes paper dust and the like adhering to the photosensitive drum 4 after transfer. The memory removal brush 22 made of a conductive brush disturbs the toner T remaining on the photosensitive drum 4 after transfer, and uniformly disperses the toner T on the photosensitive drum 4.

A process unit is constituted by the photosensitive drum 4 and the devices such as the charger 6 around them. The heat fixing device 23 is disposed on the downstream side of the photosensitive drum 4, and is provided with a heating roller 24 and a pressure roller 25 which comes into contact with the heating roller 24 at a required pressure across the paper transfer path.
It has and. Then, the recording paper P is fed between the heating roller 24 and the pressure roller 25 via the paper guide 26, and the toner image on the recording paper P is heated and fixed at a predetermined temperature. The recording paper P, on which the image fixing is completed, is passed through a paper guide 27 and a pair of guide rollers 28 to a tray 29.
Discharged on top.

As shown in FIGS. 1 and 2, one exhaust fan 30 is arranged on one side of the apparatus case 1 so as to face both the photosensitive drum 4 and the heat fixing device 23, and is illustrated. Not rotated by fan motor. The exhaust port 31 is formed on one side of the device case 1 at a position facing the exhaust fan 30. The exhaust port 32 is formed in the device case 1 so as to face the exhaust fan 30. A partition plate 33 is provided in the approximate center of the discharge port 32, and the partition plate 33 partitions the discharge port 32 into a first discharge port 34 and a second discharge port 35.

The guide plate 36 is attached to the inner surface of the lid 2 so as to correspond to the upper position of the charger 6 and the heat fixing device 23, and has a U-shaped cross section. Guide plate 3
A first duct 37 is formed between 6 and the charger 6. The first duct 37 communicates with the first outlet 34. An ozone removal filter 38 that removes ozone is attached to the first outlet 34. Therefore, ozone generated during corona discharge of the charger 6 is guided from the first duct 37 to the exhaust fan 30 side through the ozone removing filter 38 of the first outlet 34. The first outlet 34 and the first duct 3
The first passage is constituted by 7 and.

The guide plate 39 is arranged on one side of the photosensitive drum 4, and a second duct 40 is formed between the guide plate 39 and the second discharge port 35. The inlet of the second duct 40 is open to the heat fixing device 23 side. Therefore, the air heated to a high temperature by the heat generation of the heat fixing device 23 in the device case 1 is guided to the exhaust fan 30 side by the second duct 40. The first discharge port 34 and the second duct 40 form a second passage.

Therefore, by the rotation of the exhaust fan 30, the air containing ozone generated from the charger 6 is guided to the first duct 37 and passes through the ozone removing filter 38 attached to the first outlet 34. The ozone is removed,
It is discharged from the exhaust port 31 to the outside of the device case 1. Also,
The air heated to a high temperature by the heat of the heat fixing device 23 is guided to the second duct 40, sucked into the exhaust fan 30 from the second exhaust port 35, and discharged from the device case 1 through the exhaust port 31.

As described above, in the image forming apparatus of this embodiment, the duct for guiding the ozone-containing air or high temperature air generated during image formation to the exhaust fan 30 side is the first duct 3.
7 and the second duct 40 are divided into two parts. And the outlet of the first duct 37 through which the ozone-containing air passes,
That is, the ozone removal filter 38 is provided only at the first outlet 34.
I put on. Therefore, since the ozone removing filter 38 is not attached to the second discharge port 35, the high temperature air can be discharged efficiently.

As a result, the high temperature air is surely kept in the device case 1.
Since it can be discharged to the outside, it is possible to maintain the temperature inside the apparatus case 1 substantially constant, which is advantageous in terms of ensuring high printing quality, cost, and economy. Moreover, it is not necessary to use a large and large capacity fan motor, so that power consumption can be suppressed and noise can be reduced. The exhaust fan 30 and the motor are 1
As it is only a set, assembly work etc. can be done easily.
In addition, the ozone removing filter 38 may be small enough to correspond to the first duct 37, which is advantageous in terms of cost.

In the above embodiment, the transfer device 18 is also subjected to corona discharge, but since the transfer device 18 is a positive side corona discharge, no harmful ozone is generated. Of course, a separate duct corresponding to the transfer device 18 may be added and an ozone removal filter may be provided there.

The present invention is not limited to the above embodiments, but may be configured as follows, for example, within the scope of the invention. (1) In the above embodiment, the main cause of the generation of high temperature air is the heat generation of the heat fixing device 23.
To form an opening on the heat fixing device 23 side. This may be embodied, for example, by branching the second duct 40 with an auxiliary duct that opens toward a power source unit (converter or the like) other than the heat fixing device 23 that generates heat.

(2) In the above embodiment, the facsimile apparatus is embodied, but it may be embodied in a printer or a copying machine using a photosensitive drum and a heat fixing device.

[0027]

As described above in detail, according to the present invention, 1
Since ozone and high-temperature air can be discharged efficiently and reliably with one exhaust fan, the inside of the device case can be maintained at a substantially constant temperature, and as a result, the print image quality can be improved. Further, it has an excellent effect that power consumption and noise can be suppressed low.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a configuration of an exhaust fan and two ducts.

[Explanation of symbols]

1 ... Device case, 4 ... Photosensitive drum as photoconductor, 6 ...
Charging device, 23 ... Heating fixing device, 30 ... Exhaust fan, 34 ...
1st discharge port which comprises 1st passage, 35 ... 2nd discharge port which comprises 2nd passage, 37 ... 1st duct which comprises 1st passage, 38 ... Ozone removal filter, 40 ... which constitutes 2nd passage Second duct, P ... Recording paper.

Claims (1)

[Claims] 1. An image forming apparatus for forming an image on a sheet by a process unit and a heat fixing device in the apparatus case, wherein the apparatus case is provided with an exhaust fan for discharging the air in the apparatus case to the outside. An image in which the intake side of the exhaust fan is divided into a first passage through which ozone-containing air passes and a second passage through which ozone-free air passes, and an ozone removal filter is provided at the outlet of the first passage. Forming equipment.