JPH07311519A - Ozone processor - Google Patents

Abstract

PURPOSE:To highly efficiently reduce ozone with a small space by providing an ozone removing means absorbing or decomposing ozone in a discharged air flow at the discharging port of a sirocco fan. CONSTITUTION:The sirocco fan 10 sucks air from in shaft direction (x) of an impeller 10a, and discharges the air in the radius direction, and, the discharged air flow is collected by a scrolling shape of the casing of the impeller 10a, and is discharged from the discharging port. Difference between flow rate on the side close to the shaft center of the impeller 10 and flow rate on the side far from the shaft center occurs from the air flow, however, the vector direction of the air flow is nearly uniform, that is, in direction (y) in parallel with the tangent of the impeller 10a, and such rotary flow as the one caused by an axial flow fan does not occur. An ozone filter 11 as the ozone removing means absorbing or decomposing ozone in the discharged passing air flow is set on the discharging port of the fan 10. Since the direction of an average flow velocity coincides with the direction of a partial flow on the optional point of the discharging port, pressure drop is small on the entering side of the filter 11 having a fine cell, so that the air flow can easily enter.

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 electrostatic latent image corresponding to a recorded image on an electrostatic latent image carrier and developing the electrostatic latent image, and more particularly to charging and discharging of the electrostatic latent image carrier. The present invention relates to an ozone processing device for removing ozone generated when the image on the photosensitive material of the carrier is transferred onto a transfer paper. This type of image forming apparatus is used, for example, in copying machines, printers, facsimiles, and the like.

[0002]

2. Description of the Related Art A photoconductor is generally used as the electrostatic latent image carrier of the above-mentioned image forming apparatus, and the photoconductor is uniformly charged by a charging charger, a contact charging roller, a belt or the like. . The charged surface of the photoconductor is exposed by an exposure device which is an original image projection optical system including an illuminating lamp, a reflecting mirror, an imaging lens or the like, or a laser projection device, whereby an electrostatic latent image is formed. This electrostatic latent image is developed by a developing device to become a toner image, and after the charge is removed by the charge removing charger as necessary,
The toner image is transferred onto the transfer paper by a transfer charger, a transfer belt, a roller or the like. After the transfer, the photoconductor is discharged by a discharging charger as needed. An erasing exposure apparatus may be used for the erasing. Further, in order to separate the transfer paper from the photoconductor, separate charge or charge removal may be performed.

A corona discharger is most typically used for the above-mentioned charging or discharging. Since the corona discharger discharges by applying a strong electric field around a thin discharge wire, a large amount of ozone is generated. Since the amount of ozone generated mainly increases depending on the discharge discharge current, it is mainly generated from a corona charger that uniformly charges a photoconductor having a large discharge discharge current. Even in a mode in which the contact roller or belt is used for charging or discharging, ozone is generated although the amount is small.

It is not preferable in terms of pollution to release the generated ozone to the outside of the machine. For this reason, an ozone filter is used to collect or decompose ozone (hereinafter simply referred to as “decomposition”) in the machine. The ozone filter is typified by two types: an activated carbon paper filter and a catalyst filter. In both filters, the ozone decomposing ability has a filter cross-sectional area (direction orthogonal to the flow direction of the air flow passing through the filter). Area), the roughness (number of meshes) of the filter, the thickness of the filter (length in the direction of flow of the air flow), and inversely proportional to the gas passage speed.

[0005]

Therefore, if it is attempted to increase the ozone decomposing ability in a limited space, it is easy to make the mesh of the ozone filter fine, but the pressure loss of the filter increases, and the ozone decomposing is increased. It can significantly reduce efficiency. In this case, the flow from the corona discharger also flows to other parts of the machine apart from the flow to the ozone filter, and it is discharged to the outside of the machine without passing through the ozone filter.

Further, when an ozone filter is set in the vicinity of the axial fan, since the flow of the axial fan is a flow accompanied by swirling (see FIG. 8), the ozone filter is a set of straight flow passages having a small cross-sectional area. The pressure loss on the inlet side of the filter increases when the filter is placed in the vicinity. Furthermore, when an ozone filter is installed near the corona discharger (that is, in the immediate vicinity of the ozone source), a filter with a large cross-sectional area is required (an ozone filter that is long in the direction of the photoconductor thrust), and The operability of replacement also deteriorates.
A filter having a large cross-sectional area, that is, a large volume also has a high cost.

Therefore, the present invention has a first object to reduce ozone efficiently in a small space, and a second object to effectively reduce ozone with a small ozone filter, and replaces the ozone filter. The third purpose is to facilitate the above.

[0008]

The ozone processing apparatus of the present invention is for absorbing ozone generated by means (3) for charging or discharging the electrostatic latent image carrier of the image forming apparatus together with the air around it. A sirocco fan (10) and an ozone removing means (11) which is connected to the discharge port of the sirocco fan (10) and through which the discharge air flow passes, for adsorbing or decomposing ozone in the air flow (11). In addition, in order to facilitate understanding, the symbols of the corresponding elements of the embodiments shown in the drawings and described later are added in parentheses for reference.

[0009]

[Function] The sirocco fan (10) blows air in the axial direction of the impeller.
Suction from (x) and discharge in the radial direction. The discharged flow is collected by the scroll shape of the casing of the impeller and discharged from the discharge port. This flow causes a difference in flow rate between the side closer to the shaft center of the impeller and the side farther from it, but the direction of the flow vector is almost uniform and parallel to the tangent to the impeller (y). No swirling flow like the flow fan (Fig. 8) is generated. Thus, at any point on the discharge port, the direction of average flow velocity and the direction of partial flow match,
Even in the ozone filter (11) having a fine cell, the pressure loss on the inlet side is small, and the airflow easily enters the ozone filter (11).

As a result, in the ozone filter (11), the cross-sectional area (area of the surface orthogonal to the air flow direction) So is defined as the cross-sectional area of the outlet of the sirocco fan (opening area orthogonal to the air flow direction) Ss.
Even if it has the same size as the above, the discharge airflow of the sirocco fan (10) sufficiently flows, and it becomes possible to use a small ozone filter. Since the cost of the ozone filter is determined by the volume, cost reduction can be expected by using a small ozone filter.

By the way, since the sirocco fan (10) has a small amount of flow having an angle with respect to the main flow as described above, it is possible to efficiently feed air to the ozone filter (11). Immediately after the exit, the impeller axial direction (x)
And the direction (z) orthogonal to the direction (y) parallel to the tangent to the impeller
Has a non-uniform velocity distribution, and the velocity is low at a position close to the center of rotation of the impeller in the direction (z) and high at a position far from it. Therefore, when the ozone filter (11) is directly attached to the discharge port, the ozone filter (11) causes a difference in ozone decomposing ability due to a difference in inlet flow velocity in the direction (z).

Therefore, in a preferred embodiment of the present invention, the air flow discharged from the discharge port of the sirocco fan (10) and the ozone removing means (11) is directed to the ozone filter (11).
A relay flow path (10b) for guiding to is provided. This reduces the speed difference in the direction (z) while flowing through the relay channel (10b),
The flow velocity distribution on the inlet side of the ozone filter (11) becomes uniform, and the ozone reduction efficiency increases. The ozone filter (11) can also be located near the outer cover of a copying machine or the like. An ozone filter (11) was detachably connected to the relay flow path member (10b) to facilitate replacement when the ozone filter deteriorates.

Further, in one embodiment of the present invention, the ventilation area So of the ozone filter (11) which receives the air flow from the relay flow passage (10b) is larger than the ventilation area Ss of the discharge port of the sirocco fan (10). did. This allows the ozone filter (11)
At, the flow velocity of the air flow becomes low, the time for ozone to pass through the ozone filter (11) becomes long, and therefore the ozone decomposition efficiency is improved. When the ozone decomposition efficiency is sufficient, it is possible to reduce the thickness of the ozone filter. This is particularly effective when a sufficient space of the relay channel + filter thickness cannot be secured in the discharge direction (y).

By the way, even if the cross-sectional area So of the ozone filter (11) is simply increased, if the air flow only flows through the central portion of the cross-section, ozone decomposition at the periphery cannot be expected, and the ozone filter ( If the thickness of 11) (y direction) is reduced, the ozone treatment capacity will decrease. Therefore, the present inventor takes the ozone filter (11) and the sirocco fan (10) discharge port cross-sectional area ratio (So / Ss) and the distance L between the discharge port and the filter inlet as parameters, and uses the ozone filter (11) as a parameter. The same materials and the same thickness were used to compare the ozone treatment capacities. The distance L is the distance from the position of the discharge port of the sirocco fan (10) closest to the impeller to the air inlet side surface of the ozone filter (11). Actually, it is presumed that the flow velocity through the ozone filter (11) changes due to the change in the cross-sectional area So of the ozone filter (11).
(Estimated to be low) is omitted. Discharge port cross-sectional area Ss is 43 x 3
By fixing 1 mm ² and L to 24 mm, the sectional area So of the ozone filter (11) is 43 × 31 mm ² , 55 × 48 mm ² , 67 ×
There are four types, 44 mm ² and 80 × 53 mm ² . The results are shown by black dots in FIG. Since the distance L is the same, the influence of the filter cross-sectional area So is strong, but it can be seen that even if the cross-sectional area is simply increased, such an effect cannot be obtained. This is because even if the filter cross-sectional area So is increased, the flow is not uniform and does not spread. Ss ≦
By setting to So, the variation of the flow velocity in the z direction at the discharge port of the sirocco fan (10) is reduced, the ozone treatment effect of the filter (11) is increased, and the data shown in FIG.
By setting So ≦ Ss × L × 0.1, the substantially maximum ozone treatment effect can be obtained. Therefore, in one embodiment of the present invention, Ss ≦ So ≦ Ss × L × 0.1 (the unit is m
unified with m).

Further, the sectional area S of this ozone filter (11)
With the expansion of o, the relay flow path from the discharge port to the filter
In (10b), the flow path area orthogonal to the direction of the air flow (y) is also changed smoothly (linearly or in a bellmouth shape),
The pressure loss of the flow was reduced, the flow was stabilized, and the flow velocity distribution on the inlet side of the filter (11) was made uniform.

In one embodiment of the present invention, the flow velocity distribution on the inlet side of the ozone filter (11) is also provided in the relay passage (10b) from the outlet of the sirocco fan (10) to the inlet of the ozone filter (11). A uniform guide vane (14) was provided. This is also effective in increasing the ozone treatment efficiency. Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0017]

【Example】

First Embodiment FIG. 1 shows a printer incorporating the first embodiment of the present invention. The photoconductor 1 is uniformly charged by the corona discharger 3, and
The exposure is performed at the exposure position 4 by the exposure device (not shown). The electrostatic latent image generated by the exposure is developed by the developing device 5 and becomes a toner image. This toner image is transferred onto the recording paper by the transfer device 6. The recording paper showing the toner image is sent to a fixing device (not shown). The residual toner on the photoconductor 1 is cleaned by the cleaning device 2. This electrophotographic image forming process is common. By an exterior and an air flow guide plate (not shown), the air outside the exterior becomes an air flow 7 that flows from the left side of the cleaning device 2 through the corona discharger 3 in the rotation direction of the photoconductor 1 and around the corona discharger 3. Containing ozone, the flow direction around the exposure position 4 is changed to the axial direction x of the photoconductor 1 (air flow 8), and the ozone is sucked by the sirocco fan 10 through the duct 9. Sirocco fan 1
The airflow 8 sucked at 0 passes through the relay duct 10b, the ozone filter 11, and is discharged outside the printer (airflow 12).

The sirocco fan 10 is, as shown in FIG.
Air is sucked in from the axial direction x of the impeller 10a, discharged in the radial direction, collected by the scroll shape of the casing of the fan 10, and discharged from the discharge port in the tangential direction y of the impeller 10a. Due to this flow, at the discharge port, in the z direction orthogonal to the above directions x and y, a difference in flow rate, that is, a flow velocity difference occurs at a position close to and far from the axis center of the impeller, but the direction of the flow vector. Is almost uniform in the y direction, and a swirling flow unlike the axial fan shown in FIG. 8 does not occur.
In this way, since the direction of the average flow velocity and the direction of the partial flow match at any point on the fan discharge port, even with respect to the ozone filter 11 having fine cells, the pressure loss can be reduced. It is possible to send in air. The ozone filter 11 may have a cross-sectional area So perpendicular to the y-direction that is the same size as the discharge port cross-sectional area Ss of the sirocco fan, so that a small ozone filter can be used.
Since the cost of the ozone filter 11 is determined by the volume, cost reduction can be expected by using a small ozone filter.

As shown in FIG. 2, the ozone filter 11
Is installed in the filter support frame 11a inserted into the outer side opening of the relay duct 10b that penetrates the opening that opens from the inside to the outside of the exterior cover 15 of the printer. The filter support frame 11a has a pair of claws projecting above and below the edge wall of the inboard opening for inserting the filter 11, and the inner surface of the edge wall of the outboard opening of the relay duct 10b is provided on the inner surface. There is a pair of taper recesses that receive these pawls. When the ozone filter 11 is replaced, for example, in the state shown in FIG. 2, when the filter support frame 11a is rotated clockwise around the upper claw, the lower claw is disengaged from the lower taper recess and the duct is removed. 10b enters inward, the upper claw comes out of the upper taper recess and goes out of the duct 10b. Next, the filter support frame 11a is supported by the support frame 11a centering on the upper claw.
When is rotated counterclockwise (direction opposite to 13), the lower claw comes out of the duct 10b. That is, the filter support frame 11a
Comes out of the duct 10b. The ozone filter 11 in the removed support frame 11a is taken out, and an unused ozone filter is inserted into the support frame 11a instead. The support frame 11a is reattached to the duct 10b by an operation in the reverse process of the above-described removal operation. Thus, the ozone filter 11 can be easily replaced outside the printer when the ozone filter 11 deteriorates.

As described above, since the sirocco fan 10 has a small amount of flow having an angle with respect to the mainstream (y direction) as described above, it is possible to efficiently feed air to the ozone filter 11, but at the discharge port. , The speed is different at each position in the z direction. Therefore, if the ozone filter 11 is attached directly to the discharge port, a difference in ozone decomposing ability occurs due to a difference in flow rate in the z direction. In order to avoid this, in this embodiment, the relay duct 10b is fixed to the discharge port of the sirocco fan 10, and the filter support frame 11a is detachably attached to the relay duct 10b. In the relay duct 10b, the flow velocity difference of the air flow in the z direction is reduced, and the flow velocity difference is significantly reduced on the inlet side of the ozone filter 11, and the ozone decomposition efficiency of the ozone filter 11 is improved.

-Second Embodiment- A second embodiment is shown in FIG. In this case, the relay duct 10b has a wider opening on the ozone filter side than on the discharge port side, and the cross-sectional area So of the ozone filter 11 is larger than the cross-sectional area Ss of the discharge port. By increasing the cross-sectional area So of the ozone filter 11, the velocity of the airflow passing through the ozone filter 11 becomes low, the time for ozone to pass through the ozone filter 11 becomes long, and the ozone decomposition efficiency is improved correspondingly. If the ozone decomposition efficiency is sufficient, ozone filter 1
It is possible to make the thickness of 1 thin. In the discharge direction y,
This is effective when the total length of the duct 10b + the filter 11 cannot be taken sufficiently.

As already explained, the ozone filter 1
Even if the cross-sectional area So of 1 is increased, the flow does not reach around the ozone filter. That is, if the thickness of the ozone filter is reduced without the expected decrease in the flow velocity, the ozone treatment capacity will decrease. As already described, by setting So ≦ Ss × L × 0.1, the substantially maximum ozone treatment effect can be obtained. Note that L is the distance from the position of the discharge port of the sirocco fan 10 closest to the impeller to the air inflow side surface of the ozone filter 11. Therefore, in the above-described second embodiment, So ≦ Ss ×
L × 0.1.

-Third Embodiment- A third embodiment of the present invention is shown in FIG. In this third embodiment,
Although the structure is substantially the same as that of the second embodiment described above, the relay duct 10b moves away from the discharge port and approaches the filter 11 as the sectional area So of the ozone filter 11 increases. ) The shape is such that the cross-sectional area of the channel increases. Thereby, the pressure loss of the air flow in the relay duct 10b is small, the flow is stable, and the flow velocity distribution in the z direction is more uniform. As a result, the ozone treatment efficiency is further improved.

-Fourth Embodiment- Similar to the fourth embodiment, the relay duct 10b moves away from the discharge port and approaches the filter 11 as the sectional area So of the ozone filter 11 increases. The shape of the flow passage cross-sectional area is increased, that is, a bell mouth shape, and in addition, in the relay duct 10b, pressure recovery means,
That is, the guide vanes 14 are provided as means for evenly rectifying the flow. The guide vanes 14 allow a high-speed flow in the z-direction of the discharge port to flow smoothly in the low-speed region on the inlet side of the filter 11, and as a result, make the flow velocity distribution in the z-direction on the inlet side of the filter 11 more uniform. It is a plurality of linear straightening vanes. Thereby, the ozone treatment efficiency is further improved.

[0025]

EFFECTS OF THE INVENTION The sirocco fan (10) has an ozone filter (11) having a fine cell because the direction of the average flow velocity and the direction of the partial flow match at any point of the discharge port.
However, the pressure loss on the inlet side is small, and the airflow easily enters the ozone filter (11). As a result, even if the ozone filter (11) has the same cross-sectional area (So) as the cross-sectional area (Ss) of the discharge port of the sirocco fan, the discharge air flow of the sirocco fan (10) sufficiently flows and the ozone treatment effect is high. Is obtained. It is also possible to use a small ozone filter.
Since the cost of the ozone filter is determined by the volume, cost reduction can be expected by using a small ozone filter.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mechanism main part of a printer equipped with a first embodiment of the present invention.

FIG. 2 is an ozone treatment apparatus of the printer shown in FIG.
(Embodiment) is an enlarged front view, the duct 10b and the filter support frame 11a shows a fractured surface.

FIG. 3 is an enlarged perspective view of the sirocco fan 10 shown in FIG.

FIG. 4 is a front view of the second embodiment of the present invention, in which the duct 10b and the filter support frame 11a show broken surfaces.

FIG. 5 is a cross-sectional area S o of the ozone filter 11 in the embodiment shown in FIG. 2 or FIG. 4, a discharge cross-section Ss of the discharge port of the sirocco fan 10 and a discharge port / filter 11 distance L, and the ozone filter 11 It is a graph which shows the relationship with the ozone processing amount.

FIG. 6 is a front view of the third embodiment of the present invention, in which the duct 10b and the filter support frame 11a show broken surfaces.

FIG. 7 is a front view of the fourth embodiment of the present invention, in which the duct 10b and the filter support frame 11a show broken surfaces.

FIG. 8 is a perspective view showing an external appearance of an axial flow fan that is conventionally generally used for ventilation for removing ozone.

[Explanation of symbols]

1: Photoconductor 2: Cleaning device 3: Corona discharger 4: Exposure position 5: Developing device 6: Transfer device 7: Airflow 8: Airflow 9: Duct 10: Sirocco fan 10a: Impeller 10b: Relay duct 11: Ozone filter 11a: Filter support frame 12: Airflow 13: Rotation direction 14: Guide blade 15: Exterior cover

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 15/02 103

Claims (6)

[Claims] 1. A sirocco fan for sucking ozone generated by means for charging or discharging an electrostatic latent image carrier of an image forming apparatus together with air around the sirocco fan, and a sirocco fan connected to an outlet of the sirocco fan. The discharge air flow passes through,
An ozone treatment apparatus comprising: an ozone removing means for adsorbing or decomposing ozone in the air stream. 2. The ozone processing apparatus according to claim 1, further comprising a relay passage between the discharge port of the sirocco fan and the ozone removing unit, which guides an air stream discharged from the discharge port to the ozone removing unit. 3. The ozone processing apparatus according to claim 2, wherein the ventilation area So of the ozone removing means for receiving the airflow from the relay channel is larger than the ventilation area Ss of the discharge port of the sirocco fan. 4. The ozone processing apparatus according to claim 3, wherein Ss ≦ So ≦ L × Ss × 0.1, L is a gap length between the discharge port and the ozone removing means. 5. The ventilation area of the relay flow passage, which is orthogonal to the direction y in which it extends, smoothly increases from the discharge port side of the sirocco fan toward the ozone removing means side. The ozone treatment device described. 6. A rectifying means for equalizing the flow velocity distribution of the sirocco fan discharge air flow in the direction x in which the rotation center line of the impeller of the sirocco fan extends and in the direction z orthogonal to the direction y in which the relay passage extends. The ozone treatment device according to claim 2, claim 3, claim 4, or claim 5, which is provided in the flow path.