JPH0212169A - Image forming device - Google Patents

Abstract

PURPOSE:To lower ozone concentration in exhaust and to suppress the rising of temperature in the title device by forming plural air conducting paths opposed to a suction means for exhausting air in the device to the outside, making one of the air conducting paths connect to a corona discharger through an air path and providing a filter means on the air path. CONSTITUTION:The air whose ozone concentration is high around a primary electrostatic charger 4 and a pre-exposing device 10 which is the corona discharger is sucked by a fan 14 which becomes the suction means and passes through a pre-exposing window 13 as illustrated by an arrow (a). Then it flows in a main body duct 16 constituting the air path in parallel with the window 13, is conducted a guide duct 18 and exhausted to the outside of the device through an ozone filter 17. The fan 14 not only exhausts the air containing ozone from a cartridge K but also performs the function of discharging heat of a power source 15 and a fixation device 8, etc. Thus, the ozone concentration of the air exhausted to the outside of the device can be lowered and the rising of temperature is suppressed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an image forming apparatus that forms an image on an image carrier using an image forming means having a corona discharger such as a copying apparatus or a laser beam printer. .

<Prior Art> Today, with the development of information processing technology, various copying devices or image forming devices have been developed and are in use. These image forming methods include thermal recording methods.

There are thermal transfer recording methods, impact recording methods, electrophotographic methods, etc. Among these, electrophotographic methods are widely used in copying machines and the like for boat fishing.

In addition, recently, with the personalization of copying machines, laser beam printers, and the like, there has been a strong demand for image forming apparatuses to be smaller and cheaper.

The electrophotographic image forming apparatus charges a drum-shaped photoreceptor, which serves as an image carrier, with a corona discharger, and then
The photoreceptor is exposed to light to form an electrostatic latent image, and the latent image is developed with toner and transferred to a recording material to form an image.

Ozone (
03) Nitrogen oxides (NOx) are generated. When these concentrations are high, the surface of the photoreceptor is altered by ozone, NOx etc. adhere to the photoreceptor, the surface resistance of the photoreceptor decreases, and the charge on the photoreceptor is diffused, resulting in a phenomenon called image blurring. This may cause image deterioration.

In order to prevent such a phenomenon, the air around the corona discharger is sucked in by a fan or the like and exhausted to the outside.

As mentioned above, when corona discharge occurs, the air around the corona discharger contains ozone and NOx. The ozone concentration is more than I PPM, which is 0.1PP? I
It is necessary to exhaust the air at preferably 0.05 PPM or less. For this purpose, an activated carbon filter or a manganese filter having a thickness of about 10 mm is placed opposite the fan.
A catalyst filter made of metal such as titanium, aluminum, or silicon is arranged to suction filter the air inside the image forming apparatus and exhaust it to the outside.

Figure 10 shows the configuration of the above conventional ozone filter.
In the figure, the guide duct 31 is shown by arrow a and is configured to guide air from the corona discharger side to the ozone filter 32. Furthermore, air from a power source or the like indicated by arrow C is sucked directly through the ozone filter 32 without passing through the guide duct 31. In this way, all the air inside the device passes through the ozone filter 32, is sucked in, and is exhausted to the outside of the device. In addition, 33 is an ozone filter 32
It is a holder for holding.

<Problems to be Solved by the Invention> In the above conventional example, the ozone concentration contained in the air exhausted to the outside of the image forming apparatus is about 0.05 PPM.

Said ozone? In order to lower the seismic intensity, it is necessary to increase the thickness of the ozone filter or increase the number of cells.However, if the thickness of the ozone filter is increased or the number of cells is increased, The pressure loss when passing through the filter becomes large, and therefore it is necessary to increase the fan capacity.In order to reduce the ozone concentration contained in the exhaust air, it is necessary to increase the size of the image forming apparatus. There is a risk of increasing the cost of ozone filters and ozone filters.

In addition, as in the conventional example above, when all the air inside the device is sucked through the ozone filter by one fan, air containing almost no ozone from the power supply section and fixing section and ozone from the corona discharger are mixed. Since highly concentrated air passes through the ozone filter, there is a risk that the decomposition efficiency of the filter may deteriorate or that partial deterioration of the filter may be accelerated.

An object of the present invention is to suck and exhaust air with a high ozone concentration through an ozone filter when exhausting air inside an image forming apparatus to the outside, and to suck and exhaust other air without passing through a filter. It is an object of the present invention to provide an image forming apparatus that can increase the decomposition efficiency of the ozone filter, thereby lowering the ozone concentration in the exhaust gas and lowering the temperature rise inside the VT apparatus.

Means for Solving the Problems> Means for solving the above problems is provided in an image forming apparatus that forms an image on an image carrier by an image forming means having a corona discharger. A suction means for suctioning and exhausting air to the outside, a plurality of air conduction passages formed opposite to the suction means, and a corona discharge TL device formed between one of the plurality of air conduction passages and the corona discharge TL device. It has an air passage for conducting air around the corona discharger to the suction means, and a filtration means for filtering the air passing through the 11th layer I air passage.

According to the above means, the image forming apparatus is formed with a plurality of four air passages facing the suction means for exhausting the air inside the apparatus to the outside, and one of the air passages is connected to the corona discharger. Because the air passage conducts through the air passage and the air passage is provided with a filtration means, ozone and N generated by corona discharge are removed.
The air containing O8 is sucked through one of the plurality of air passages formed opposite the suction means, flows along the air passage connecting the corona discharger and the suction means, and is filtered by the filtration means. be done.

Furthermore, air outside the vicinity of the corona discharger is sucked through a plurality of air conduction paths formed opposite to the suction means, other than the conduction path that conducts the air path from the corona discharger. . Immediately after passing through the air guide path, the air sucked from the corona discharger and the air sucked from sources other than the corona discharger are mixed and exhausted to the outside of the image forming apparatus.

Further, in the above means, the air with high ozone concentration around the corona discharger passes through the ozone filter, and the air with low ozone concentration outside the corona discharger is directly sucked by the suction means without passing through the ozone filter. This reduces the amount of air passing through the ozone filter,
Therefore, pressure loss in the filter can be reduced.

Therefore, it is possible to increase the amount of suction air by the suction means, improve the amount of ventilation inside the device, and reduce the temperature rise inside the device. In addition, by passing only air with high ozone concentration through the ozone filter,
The ozone splitting efficiency in the filter can be increased.

<Embodiment> An embodiment of an image forming apparatus to which the above means is applied will be described below with reference to the drawings.

FIG. 1 is a cross-sectional explanatory diagram of the image forming apparatus, FIG. 2 is a plan view thereof, FIG. 3 is an explanatory diagram of the cartridge attachment/detachment state, and FIG.
The figure is an explanatory diagram of the holder.

First, the schematic structure of the image forming apparatus will be explained with reference to the drawings. In the figure, a laser beam modulated according to an image signal is scanned and outputted from a scanner unit 1 including a laser and a polygon mirror correction lens system, and a folding mirror 2
The light is reflected and irradiated onto the photosensitive drum 3, which serves as an image carrier. The photosensitive drum 3 is uniformly charged by a primary charger 4, which is a corona discharger, and forms an electrostatic latent image by laser beam irradiation. The electrostatic latent image is developed with toner 5a in the developing device 5 to form a toner image.

On the other hand, a recording material 7 such as plain paper or plush film stored in the force set 7a is fed by a paper feed roller p to a registration roller r in synchronization with the formation of a latent image on the photosensitive drum 3. The recording material 7 is a registration roller r
In synchronization with the leading edge of the latent image formed on the photosensitive drum 3, the toner image is conveyed to a transfer charger 6, which is a corona discharger, and the toner image is transferred onto a recording material 7 by the transfer charger 6. The recording material 7 to which the toner image has been transferred is transported by the conveyance guide g.
, is permanently fixed by the fixing device 8, and is discharged to the outside of the apparatus.

Further, toner remaining on the photosensitive drum 3 is removed by a cleaning device 9. Further, the charging history of the photosensitive drum 3 is erased by a pre-exposure device 10 which is a corona discharger.

The photosensitive drum 3. -Charger 4. The developing device 5 cleaning device 9 and cover 11 are integrally formed as an image forming unit (hereinafter referred to as a cartridge) K, which is attached to and detached from the main body of the apparatus as shown in FIG. Note that the cover 11 protects the photosensitive drum 3 when the cartridge K is removed from the main body of the apparatus.
It has the function of blocking light and preventing dust from adhering to the surface.

The air with high ozone concentration around the charger 4 and the pre-exposure device 10 is sucked by the fan 14 serving as a suction means, and is drawn through the pre-exposure window 13 as shown by arrow a in FIGS. 1 and 2. The air passes through the main body duct 16 that forms an air passage in parallel with the window 13 (in FIG. 1, the flow is from the top to the bottom of the drawing and is indicated by ■), and is led to the guide duct 18 and passes through the ozone filter 17. and is exhausted to the outside of the device. In addition to exhausting ozone-containing air from the cartridge K, the fan 14 is also connected to a power source 15. It functions to exhaust heat from the fixing device 8, etc.

Next, a detailed explanation will be given of a configuration for exhausting air inside the image forming apparatus to the outside.

First, the main body dowel 6 has side walls 16a, 16b, and 16c.

16d is formed into a cylindrical shape, and one end is connected to the closing member 1.
6e. As shown in FIG. 2, an opening 16f facing the guide duct 18 is formed at the other end. A pre-exposure device l is installed at a predetermined position on the side wall 16d.
O is fixed.

Also, when cartridge K is installed in the main body of the device, the first
As shown in the figure, the cover 11 for cleaning 59 cases is fitted into the main body guide 16, and the pre-exposure window 13 formed along the cleaning device 9 is located within the main body guide 16, facing the pre-exposure device 10. It is configured to open.

The cartridge also includes a photosensitive drum 3. Developing device5. The cleaning device 9 and the cover 11 house the primary charger 4 in a substantially airtight manner.

Therefore, the primary charger 4 and the pre-exposure device 10 are arranged in a substantially sealed space formed by the cartridge and the main body duct 16. Then, when the fan 14 is driven to suck air, the air inside the device enters the cartridge through the exposure window 12, as shown by the arrow, passes around the charger 4, and exits from the pre-exposure window 13. It flows into the main body duct (16), passes around the pre-exposure device 1O arranged in the main body duct 16, and reaches the ozone filter 17.

Next, the guide duct 8 is constructed as shown in FIG. This guide duct 18 is located between the main body duct 16 and the fan 14, and guides the airflow between them. For this reason, the guide duct ratio is 0, which is formed in a shape that matches the positional relationship between the main body duct 16 and the fan 14. In this embodiment, the guide duct ratio is 0. Since the guide duct H8 and the fan 14 are provided perpendicularly to each other, the guide duct H8 is configured to change the direction of the air from the main body duct 1-16 by 90 degrees and flow it in the direction of the fan 14.

11; The guide duct 18 has the opening 1 of the main body duct eye 6.
It is formed with an opening 18a approximately equal to 6" and an opening 18b approximately equal to the air conduction path 19a formed in the holder 19.

Next, the ozone filter 17 is removably attached to a holder 19 fixed to the main body of the apparatus. In this embodiment, the ozone filter 17 is a honeycomb activated carbon filter with 500 cells per square inch and a thickness of 2011 mm.

Next, the holder 19 serves as an air guide path when the fan 14 sucks the air inside the apparatus body. For this reason, the holder 19 is fixed to the main body of the apparatus at a position facing the fan 14, and a plurality of air conduction passages 19a and 19b are formed as shown in FIG. 4.

The conduction path 19a is a conduction path for allowing air with a high ozone concentration to pass through the ozone filter 17.

Further, the conduction path 19b is a conduction path for passing air from the power supply section 15 or the fixing device 8, which is indicated by an arrow C in FIG. In this embodiment, the conduction path 19
An ozone filter 17 is removably attached to a. However, there is no filter in the conduction path 19b, and there is nothing that obstructs the airflow.

Therefore, no pressure loss occurs when the air shown by arrow C passes through the conduction path 19b, and therefore the amount of air from the power supply section 15 or the fixing device 8 passing through the conduction path 19b increases.

Next, the fan 14, which serves as a suction means, sucks the air inside the main body of the apparatus and exhausts it to the outside. As the fan 14, conventionally known devices such as a sirocco fan or an axial fan can be used.

Next, ozone removal in the image forming apparatus configured as described above will be explained.

As the ozone filter 17, a filter having a thickness of 20 to 40 mm, which is thicker than conventionally used filters, can be used.

In other words, in the conventional technology, air with high ozone concentration and air containing no ozone are sucked through an ozone filter.
When the filter is exposed to illumination, the pressure loss is large, and if the filter is made thicker, the air volume decreases, and the amount of ventilation inside the device decreases. Also, in this case, since almost all of the air in the device that is sucked passes through the filter, the amount of air passing through the filter increases, which may reduce the efficiency of ozone decomposition by the filter, or cause dust in the air to adhere to the filter. This reduces ozone decomposition efficiency.

However, in this embodiment, only air with a high ozone concentration is sucked through the ozone filter 17, and air that does not contain ozone is sucked in without passing through the filter, so the thickness of the filter is
In this case, the volume of air with high ozone concentration will decrease (the wind speed when passing through the ozone filter 17 will decrease), but it will be possible to increase the volume of air that does not contain ozone, which will reduce the amount of ventilation inside the device. You can do a lot.

Furthermore, as shown in Figure 5, which shows the relationship between wind speed and removal rate in an ozone filter, when filters with the same number of cells are used, the lower the wind speed of the air passing through the filter, the better the ozone removal rate. . Therefore, if air with high ozone concentration is uniformly passed through the ozone filter 17 and the thickness of the filter 17 is increased to lower the wind speed of the air passing through the filter 17, the ozone decomposition efficiency will be increased. That is, the ozone removal rate is improved.

For example, in a conventional image forming apparatus, the thickness lQm (50
When using a honeycomb activated carbon filter with 0 cells, the wind speed of the air with high ozone concentration indicated by arrow a is approximately 1.0 m/
s, and the wind speed of the air not containing ozone, indicated by arrow C, was approximately 0.4 m8. At this time, the ozone exhausted to the outside of the device is approximately 0.05 PPM, and the power supply section 15
The temperature rise in the temperature was also large.

In this example, as a result of using a honeycomb-shaped activated carbon filter with a thickness of 20+n and 500 cells, the wind speed of the air with high ozone concentration, indicated by arrow a, was 0.8 m/s, and the wind speed of air with high ozone concentration, indicated by arrow C, was 0.8 m/s. Air wind speed is 0.5n+/s
Met. At this time, the ozone concentration inside the device did not increase, and as the wind speed when passing through the ozone filter 17 decreased, the ozone decomposition efficiency increased, and the ozone concentration exhausted to the outside of the device was 0.0 IPPM or less. . Also, because the air wind speed indicated by arrow C has increased compared to before,
The upper temperature limit inside the device was also lowered.

Furthermore, in this example, since air with high ozone concentration uniformly passed over substantially the entire surface of the ozone filter 17, extreme deterioration did not occur in a portion of the filter 17.

In addition, the occurrence of scratches on the surface of the ozone filter 17 was reduced, and the life of the ozone filter 17 could be extended.

Further, in this embodiment, the air from the conduction path 19a that has passed through the ozone filter 17 and has a reduced ozone concentration, and the ozone-free air that has passed through the conduction path 19b are transferred to the conduction path 19a.
By stirring and mixing the air with the fan 14 immediately after passing through the air passages a and 19b, the ozone-containing air is diluted with the ozone-free air, and the ozone concentration of the exhausted air can be reduced.

When air containing ozone and air not containing ozone were stirred and mixed in this way, the ozone concentration of the mixed air was actually measured to be lower than that of simple dilution. The reason for this is thought to be that the temperature of the air that does not contain ozone has increased due to the temperature rise of the power supply unit 15 and the like, and that this air contacts the air that contains ozone to promote the decomposition of ozone.

In this embodiment, by providing a slight gap between the main body duct 6 and the guide duct 18 as shown in FIG. It is suctioned through.

[Other Examples]

6 and 7 are explanatory diagrams of other embodiments, and FIG.
7 is a plan view of the image forming apparatus, and FIG. 7 is an explanatory view of the surroundings of the holder 19. In FIG. The explanation will be omitted.

In this embodiment, the shape of the guide duct 20 is changed, and the outer wall 20a of the guide duct 20 clearly separates the flow of ozone-concentrated air from the main body duct 16 and ozone-free air from sources other than the main body duct 16. Separate. : is possible. That is, the air with high ozone concentration from the main body duct 16 is conducted from the opening 20b of the guide duct 20 to the conduction path 21a formed in the holder 21. In addition, ozone-free electricity or air from the fixing device 8 flows along the outer wall 20a of the guide duct 20 and flows through the conduction path 21.
Conducts to b.

By forming the guide duct 20 and the conductive paths 21a and 21b as described above, it becomes possible to clearly separate air with a high ozone concentration and air that does not contain ozone for suction, thereby extending the life of the ozone filter 17. It can be made longer.

8 and 9 are explanatory diagrams of still another embodiment, with FIG. 8 being a plan view thereof and FIG. 9 being a side view thereof. In the drawings, the same parts and parts having the same functions as those in the previous embodiment are given the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, in addition to providing an ozone filter 17 in a conduction path 19a formed in a holder 19, an ozone filter 22 is also provided near the opening 16f of the main body duct 6.

Since the wind speed near the opening 16 of the main body duct 16 is relatively slow and the ozone concentration is high, by placing the ozone filter 22 here, the main body duct 16
This makes it possible to efficiently remove ozone from air with high ozone concentration passing through the air. Therefore, the ozone concentration of the air sucked in by the fan 14 and exhausted to the outside of the apparatus can be lowered.

<Effects of the Invention> As described above in detail, the image forming apparatus of the present invention has a plurality of air conduction passages formed opposite to the suction means for exhausting the air inside the apparatus to the outside, and one of the air conduction passages. Since the air passage and the corona discharger are connected to each other by an air passage, and the air passage is provided with a filtering means, the air containing ozone and NOx generated by the corona discharge is filtered through the air passage formed opposite the suction means. It is drawn in through one of the passages, flows along an air passage communicating between the corona discharger and the suction means, and is filtered by the filtration means. Furthermore, air outside the vicinity of the corona discharger is sucked through a plurality of air conduction paths formed opposite to the suction means, other than the conduction path that conducts the air path from the corona discharger. . Immediately after passing through the air guide path, the air sucked from the corona discharger and the air sucked from sources other than the corona discharger are mixed and exhausted to the outside of the image forming apparatus.

Further, in the above means, the air with high ozone concentration around the corona discharger passes through the ozone filter, and the air with low ozone concentration outside the corona discharger is directly sucked by the suction means without passing through the ozone filter. This reduces the amount of air passing through the ozone filter,
Pressure loss in the filter can be reduced. Therefore, the amount of air sucked by the suction means from the part that does not generate ozone can be increased, so the amount of ventilation inside the device is increased, and therefore the temperature rise inside the device can be reduced.

In addition, because only air with high ozone concentration passes through the ozone filter, increasing the thickness of the filter has little effect on the amount of ventilation inside the device, which reduces the ozone decomposition efficiency of the ozone filter. It has the characteristic of being able to increase the

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram of the image forming apparatus, FIG. 2 is a plan view thereof, FIG. 3 is an explanatory diagram of the cartridge attachment/detachment state, and FIG.
FIG. 5 is an explanatory diagram of the holder, FIG. 5 is a filter performance curve, FIGS. 6 to 9 are explanatory diagrams of other embodiments, and FIG. 10 is an explanatory diagram of the prior art. 1 is a scanner unit, 2 is a mirror, 3 is a photosensitive drum,
4 is a primary charger, 5 is a developer, 6 is a transfer charger, 7 is a recording material, 8 is a fixing device, 9 is a cleaning device, 1O is a front exposure device, 11 is a cover, 12 is an exposure window, 13 is a front exposure window, 1
4 is a fan, 15 is a power supply section, 16 is a main body duct, 17.
22 is an ozone filter, 18.20 is a guide tallit,
19.21 is a holder, 19a, 19b. 21a and 21b are conductive paths.

Claims (1)

[Scope of Claims] In an image forming apparatus that forms an image on an image carrier by an image forming means having a corona discharger, there is provided a suction means for sucking air inside the image forming apparatus and exhausting it to the outside. and a plurality of air conduction passages formed to face the suction means; and a plurality of air conduction passages formed between one of the plurality of air conduction passages and the corona discharger for conducting air around the corona discharger to the suction means. An image forming apparatus comprising: an air passage; and a filter for filtering air passing through the air passage.