JPH06317950A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device having the usable time of the whole filter extended as much as possible by using a winding type filter and increasing the air flow volume of a fan when the filter gets clogged so as to successively perform the function of the filter. CONSTITUTION:The winding type filter 25 is provided opposite to the fun 27 by which the sucking air flow is generated, and minute suspended matter such as toner and paper particles in the image forming device is stuck to the filter 25. Then, this device is constituted so that the air flow volume of the fun 27 is increased when the filter 25 gets clogged in accordance with the sticking.

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 having a fan and a filter, such as a copying machine, a printer and a facsimile.

[0002]

2. Description of the Related Art This type of image forming apparatus is provided with a corona discharger for performing various kinds of charging, but when corona is discharged by this, products such as ozone are generated.
Also, in electrophotographic and electrostatic recording type image forming apparatuses, fine particles such as toner and paper dust are floating around the photoconductor, and such fine floating particles are applied to the charge wire of the corona discharger. If attached, discharge unevenness is likely to occur.

Therefore, in this kind of image forming apparatus, a predetermined slit (which will be described later) is provided in the charge wire case of the corona discharger, and a suction air flow path is connected to this portion, and this air flow path is connected to this air flow path. The fan provided is driven to remove fine suspended matter while placing it on the suctioned air stream. Furthermore, ozone generated during corona discharge is captured and decomposed by an ozone filter provided at a predetermined position in the suction air flow path.

On the other hand, in an electrophotographic image forming apparatus, a halogen lamp or a fluorescent lamp is used to illuminate and scan a document, but if such a light source continues to be turned on, the inside of the image forming apparatus is changed. Gets quite hot. Further, when offset-preventing silicone oil vaporized from the fixing device provided in the image forming apparatus or scattered toner in the image forming apparatus enters the optical system, they adhere to optical components such as mirrors and lenses. This causes image blurring and the like.

Therefore, in this type of image forming apparatus, a fan is driven to take in the outside air into the image forming apparatus to cool the inside of the apparatus or to guide the internal airflow toward the optical system, such as a mirror and a lens. Prevents dirt on optical parts. In this case, an air filter is used to prevent dust in the outside air from entering the image forming apparatus.

As described above, the image forming apparatus is provided with various filters such as an ozone filter and an air filter which are paired with a fan, and the air flow generated by the fan is passed through the filter to allow ozone, fine suspended matter or dust. However, if the filter becomes clogged and becomes awful, the air volume will decrease and the function of the filter will be impaired.

Therefore, in the past, a service person regularly inspected the image forming apparatus, and at this time, the filter having the clogging was cleaned or replaced, but this is not done. In this case, the function of the filter remains impaired as described above, causing various problems as described above.

On the other hand, the present applicant has already proposed a technique for detecting clogging of a filter and urging a person who handles the image forming apparatus to clean or replace the filter (Japanese Patent Application No. 2000-242242). No. 3-159507). However, even with this technique, the filter may not function properly until the service person or user cleans or replaces the filter, and the image may be adversely affected during that time. In addition, a service person may have to go out and inspect each time.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to increase the fan air flow rate when the filter is clogged so that the function of the filter can be continued.
An object of the present invention is to provide an image forming apparatus which extends the usable period of the filter as much as possible.

[0010]

In order to achieve the above object, the present invention forms a pair of a fan whose air volume can be changed according to the magnitude of a drive current, and which is arranged in a fan air passage. A filter, a detection unit that detects clogging of the filter, and a control unit that changes the magnitude of the drive current so that the fan air volume becomes larger when the clogging is detected by the detection unit than before the detection. An image forming apparatus including the above is proposed.

In order to achieve the above object, another invention is a wind-up type fan, which is paired with a fan whose air volume can be changed according to the magnitude of a drive current and which is arranged in a fan air passage. A filter, a detection unit that detects clogging of the filter, and a control unit that changes the magnitude of the drive current when the clogging is detected by the detection unit so that the fan air volume becomes larger than before detection. The present invention proposes an image forming apparatus including a filter winding means for winding a filter and positioning a new filter surface in a fan air passage when a drive current of the fan exceeds a predetermined reference value. .

It is effective that the filter is an ozone filter for trapping products generated by corona discharge.

Further, it is effective that the filter is an air filter for capturing fine suspended matter.

Further, it is effective that the fan is a fan for cooling the inside of the apparatus and the filter is an air filter for preventing dust from entering the inside of the apparatus.

Further, it is effective that the control means is a means for changing the magnitude of the drive current so that the drive current returns to the initial state after the filter is wound up.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view of an installation component such as a fan and a filter, which is provided in the image forming apparatus according to the embodiment of the present invention. The general outline of the apparatus will be clarified below with reference to FIG.

The image forming apparatus shown in this figure is of an electrophotographic type, and in this image forming apparatus, as is well known, the steps of charging, exposing, developing, transferring, fixing, cleaning and discharging are performed. Are being carried out sequentially.

A drum-shaped photosensitive member 1 disposed substantially in the center of the image forming apparatus is driven to rotate in the direction of the arrow shown in the figure. During this rotation, first, corona discharge of the charger 2 causes the surface of the photosensitive member 1 to rotate. A static charge is applied to the surface, and its surface is uniformly charged. This is the charging process.

On the other hand, in the next exposure step, the original 4 placed on the contact glass 3 is illuminated and scanned with an image by the light source 5, and this scanning light image is reflected by the mirrors 6.
An image is projected on the photoconductor 1 via the lenses 7, 8 and 9 and the mirror 10, respectively, whereby an electrostatic latent image corresponding to the image of the original 4 is formed on the photoconductor 1.

Then, the electrostatic latent image is visualized as a toner image by the toner of the developing device 12. And
The toner image is transferred onto the transfer paper 15 by corona discharge by the transfer charger 13. After this transfer, the transfer paper 15 is separated from the photoconductor 1 by the separation charger 14, passes through the fixing device 16, and is discharged onto the tray 17.

Untransferred toner remains on the surface of the photoconductor 1 after the transfer of the toner image, and this toner is removed from the photoconductor surface by the cleaning member of the cleaning device 18. Then, the charge removal lamp 11 removes the residual charges on the surface of the photoconductor, and the surface of the photoconductor is returned to the initial state.

By the way, as described above, ozone is generated from the chargers 2, 13 and 14 for charging, transferring and separating when corona discharge occurs. Therefore, in order to capture and decompose the ozone, a duct having a fan and an ozone filter is provided on the inner side of the image forming apparatus in FIG.

Returning to FIG. 1, a slit-shaped exhaust port 21 is formed in the main body exterior plate 19 on the back side (back side) of the image forming apparatus, and the exhaust port 21 has one end of a duct 22. Parts are connected. The duct 22 is branched at an intermediate portion in the image forming apparatus, and each branched portion (not shown)
Are connected to the chargers 2, 13 and 14 shown in FIG. That is, the casing slits 2a, 1 in the figure
3a and 14a, respectively.

A fan 27 is provided in the duct 22,
This fan has an integrated motor for rotating the fan. Then, the fan 27 rotates at the same time when the main switch (not shown) of the image forming apparatus is turned on, and the rotation speed changes according to the magnitude of the drive current,
This allows the amount of air sent to be changed. When the fan 27 rotates, air flows through the fan air passage 24 in the duct 22, and the direction A of the air flowing through the air passage 24 is the direction in which the air travels from the above-mentioned chargers to the air outlet 21. Has become. An ozone filter 26 is arranged in the air passage 24 so as to face the fan 27. The ozone filter 26 is fixedly provided in the duct 22.

The ozone generated during the corona discharge rides on the suctioned air flow in the duct 22 and reaches the site of the ozone filter 26. Then, ozone is captured and decomposed at this portion. After this, the air from which ozone has been removed is the exhaust port 21.
More discharged. That is, it appears on the back side of the main body of the image forming apparatus.

However, toner, paper powder, and the like are floating in the ozone generating portion described above, and when the fine suspended matter is clogged in the ozone filter 26, the ozone decomposing performance is deteriorated. Therefore, a wind-up type air filter 25 is provided so as to face or face the surface of the ozone filter 26 on the side opposite to the fan 27, and the windable air filter 25 can freely move in and out of the duct 22. The air filter 25 forms an example of a filter that forms a pair with a fan and is arranged in the fan air passage. The fine suspended matter moving along with the suctioned air flow adheres to the ozone filter 26 before reaching the ozone filter 26.
It does not adhere to and does not deteriorate the ozone decomposing performance.

However, fine suspended matter such as toner and paper powder adheres to the air filter 25, increasing the adhered amount,
If the air filter 25 becomes severely clogged, the fan 27
As a result, the amount of air blown by the air filter 25 decreases, the ability of the air filter 25 to capture fine suspended matter decreases, and the ozone decomposing function of the ozone filter 26 also becomes impaired. Furthermore, it becomes difficult to place fine suspended matter at each charger site, products such as ozone associated with corona discharge, on the suctioned air stream.

Here, as shown in FIG.
A light emitting element 28 made of a light emitting diode and a light receiving element 29 made of a phototransistor are fixedly provided on the upper and lower inner wall portions of these elements 28, 29, respectively.
Thus, the light reflection type clogging detection sensor 34 (FIGS. 4 and 5) is configured. As I explained earlier, fan 2
When 7 rotates, a suction air flow is generated in the direction of arrow A, and fine suspended matter such as toner riding on this suction air flow causes the duct 2 to move.
It adheres to the air filter 25 in the inside of 2, and as the adhered amount increases, it becomes a clogging state. In such a state, the light amount of the reflected light 20 from the filter surface decreases.

As shown in FIG. 4, the clogging detection sensor 34
Outputs from the light emitting element (light emitting diode) 28 and the light receiving element 29 of the light receiving element (phototransistor) 29 enter the control unit via the operational amplifier 35 and the A / D converter 36. When the air filter 25 is clogged, toner or paper dust adheres to the filter surface as described above, and the amount of reflected light decreases, so a reference value for the amount of reflected light should be set in advance. This makes it possible to detect clogging (dirt) on the filter surface.

By detecting the difference in the reflected light amount,
The clogging state of the filter can be detected. Clogging detection sensor 34 having light emitting element 28 and light receiving element 29
Is an example of a detection unit that detects clogging of the filter. When the filter is clogged, the drive current of the fan changes. However, as a means for detecting the filter clogging, a means for detecting such a change in the drive current may be used.

When the clogging detection sensor 34 detects clogging of the air filter 25, the number of rotations of the fan 27 is increased to increase the air volume thereof before the clogging is detected. There is. As a result, the air filter 25 in the fan air passage 24 can be continuously used until the air filter 25 becomes severely clogged so that it does not function, and the use period of the filter can be extended. Here, the clogging of the filter is clogging before reaching a severe clogging state in which the function of the filter cannot be maintained.

FIG. 5 is a control block diagram corresponding to the embodiment of the present invention, in which the value detected by the clogging detection sensor 34 is compared with a preset reference value, and the air filter is based on the comparison result. When the clogging of 25 is detected, a control signal is sent from the control unit to the drive power source of the fan 27, and the fan 27 is rotationally driven so as to increase its air volume more than ever. Thus, when clogging is detected by the filter clogging detection means, the magnitude of the drive current of the fan 27 is changed by the control means composed of the control unit and the driving power source, whereby the rotation speed of the fan 27 is clogged. The air volume is increased from that before detection, and the air volume is increased from that before detection of clogging. Accordingly, even if the air filter 25 is clogged, the air volume by the fan 27 can be brought close to the initial state (the state before the clogging occurs), and the filter 25 can be continuously used.
The usage period of can be extended.

The number of times the above operation is performed, the air filter 25 becomes more and more clogged. Therefore, there is a limit in the above-mentioned operation alone, and an excessive load is applied to the motor of the fan 27, which may cause a failure. Therefore, the present example is further configured as follows.

Returning to FIG. 1, the air filter 25 is of the winding type as described above, and is supplied from one roll portion 25A and the other roll portion 25B.
It is designed to be wound around. The motor 31 drives the filter 25 to be wound up, and when the motor 31 rotates, the filter 25 rolls through the motor pinion 32 and the roll shaft gear 33.
Is wound up by. When the motor 21 is operated and the filter part which has been used so far is wound around the roll part 25B and the new filter surface is supplied to the part of the ozone filter 26, the function of the filter can be continued. Become.

As described above with reference to FIG. 5, when the clogging of the air filter 25 is detected by the clogging detection sensor 34, within the range of the lower limit and the upper limit of the rotational speed of the fan 27, the above-mentioned operation is performed. Thus, the air volume by the fan 27 is increased more than before the clogging is detected. Then, the air filter 25 is further clogged, and even if the drive current of the fan 27 is further increased, the function of the filter 25 cannot be performed or the motor of the fan 27 is adversely affected. When the actual drive current exceeds the drive current before the above, that is, the upper limit (predetermined reference value) of the drive current of the fan 27, the control unit drives the drive power source of the filter take-up motor 31 which is the filter take-up means. A control signal is output to the motor 31, the motor 31 is activated, and the air filter portion that has been used so far is wound up, and at the same time, a new filter surface is placed in the fan air passage 24, that is, in a portion opposite to the ozone filter 26.

According to this embodiment, it is not necessary to clean or replace the filter, and the use period of one roll of the filter can be greatly extended. Note that the control means for changing the magnitude of the drive current according to the detection of clogging is a means for changing the magnitude of the drive current so that the drive current returns to the initial state after the air filter 25 is wound up. Since the magnitude of the input current to the fan 27 is returned to the initial state, it is possible to surely suppress the fluctuation of the air volume over time, and to reduce the load on the motor of the fan while continuing the function of the filter. Can be carried out.

As described above, when the filter 25 is clogged, a roll-up type filter capable of automatically delivering a new filter surface is used so that cleaning and replacement of the filter can be avoided. Become. Moreover, when clogging occurs, the function of the filter can be continuously maintained by not increasing the new filter surface immediately and increasing the air volume of the fan. Then, if a new filter surface is provided in a clogging condition where the function maintenance of the filter can no longer be performed, the use period of the entire filter can be extended.

In the above embodiment, the case where the filter for which clogging is detected is the air filter 25 for trapping fine suspended matter has been described. However, such a filter is used as an ozone filter for trapping products accompanying corona discharge. The present invention can be applied even when Further, the fan may be a fan for cooling the inside of the apparatus, and the filter paired with the fan may be an air filter for preventing dust from entering the inside of the apparatus. In this case, the air filter is used for image formation. It is provided close to an air intake port provided on an exterior plate (not shown) of the apparatus body.

Although it is different from the configuration in the claims, when the filter clogging is detected by the detecting means as described above, it is judged that it is time to replace the filter, and the fan drive current is determined. The filter take-up motor is immediately activated by the control signal output from the control unit to the drive power supply without changing the current, the take-up filter part is taken up, and the new filter surface is used as the fan air passage. It can also be configured to be located.

[0041]

According to the image forming apparatus of the first aspect, even if the filter is clogged, the fan air volume increases and the filter can be continuously used, so that the period of use of the filter can be extended.

According to the image forming apparatus of the second aspect,
When the filter becomes clogged, a new air filter surface can be automatically delivered, which eliminates the need for cleaning the filter and frequent filter replacement.
It is possible to extend the use period of one roll of the roll-up type filter.

According to the image forming apparatus of claim 3,
Products such as ozone associated with corona discharge can be stably captured over a long period of time.

According to the image forming apparatus of claim 4,
It is possible to stably capture fine suspended matter such as toner and paper powder for a long period of time, and it is possible to prevent such fine suspended matter from adhering to the charge wire and the like for a long period of time.

According to the image forming apparatus of the fifth aspect,
It is possible to prevent dust from entering the image forming apparatus for a long period of time, and it is possible to prevent the dust from adhering to a light source or a fixing device that generates heat for a long period of time.

According to the image forming apparatus of the sixth aspect,
The function of the filter can be performed for a long time while reducing the load on the fan.

[Brief description of drawings]

FIG. 1 is provided in an image forming apparatus according to an embodiment of the present invention,
FIG. 3 is a perspective view of installation components such as a fan and a filter.

FIG. 2 is a schematic configuration diagram of the image forming apparatus.

FIG. 3 is a duct cross-sectional view of a portion where a sensor that detects clogging of a filter is installed.

FIG. 4 is a circuit diagram showing an example of filter clogging detection means.

FIG. 5 is a control block diagram for driving a filter winding motor when a filter is clogged and for increasing a fan air volume.

[Explanation of symbols]

 24 Fan Blower 25 Filter 27 Fan

Claims (6)

[Claims] 1. A fan whose air volume can be changed according to the magnitude of a drive current, a filter which is paired with this fan and which is disposed in a fan air passage, and a detection means which detects clogging of this filter. An image forming apparatus comprising: a control unit that changes the magnitude of a drive current so that the fan air flow becomes larger than that before detection when clogging is detected by the detection unit. 2. A fan whose air volume can be changed according to the magnitude of a drive current, a wind-up type filter which is paired with this fan and which is arranged in a fan air passage, and detects clogging of this filter. Detecting means, a control means for changing the magnitude of the drive current so that the fan air volume becomes larger than that before detection when clogging is detected by the detecting means, and the drive current of the fan is a predetermined reference. An image forming apparatus comprising: a filter winding means for winding a filter and positioning a new filter surface in the fan air passage when the value is exceeded. 3. The image forming apparatus according to claim 1, wherein the filter is an ozone filter for capturing products generated by corona discharge. 4. The image forming apparatus according to claim 1, wherein the filter is an air filter for capturing fine suspended matter. 5. The image forming apparatus according to claim 1, wherein the fan is a fan for cooling the inside of the apparatus, and the filter is an air filter for preventing dust from entering the inside of the apparatus. 6. The image forming apparatus according to claim 2, wherein the control unit is a unit that changes the magnitude of the drive current so that the drive current returns to the initial state after the filter is wound up.