JP2002229331A - Toner scattering preventing device and image forming device equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner scattering preventing device capable of continuously attaining a toner scattering preventing effect and having no possibility that image quality is deteriorated. SOLUTION: This toner scattering preventing device is equipped with an exhaust means 72 exhausting air inside a developing device 14 through an exhaust path made of tubes 71 and 73, a toner collecting means collecting toner from the air exhausted by the exhaust means and made of oriented porous PTFE, for example, and a toner storage means 74 positioned on the upstream side of the toner collecting means and storing the toner collected by the toner collecting means without dropping it in the toner in the device 14. For example, by attaching the toner collecting means to a tank constituting the toner storage means so as to cover the opening of the tank, the toner is collected though the air is made to pass.

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 such as a copying machine, a printer, a facsimile, or a multifunction peripheral thereof, in which charging, writing, development, transfer, cleaning, etc. are repeated on an image carrier. The present invention can be applied to an image forming apparatus such as a color / multicolor / monochrome image forming apparatus in which toner images are sequentially formed by an electrophotographic method, and the toner images are sequentially transferred and recorded on a sheet. Also, the present invention relates to a toner scattering prevention device for preventing toner from floating and scattering from a developing device in such an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus,
For example, there is a problem that toner not involved in development scatters from a developing opening of the developing device and contaminates the inside of the image forming apparatus main body, and for example, there is a problem that image quality is deteriorated by being attached to an image carrier or a sheet. In addition, there is a problem that the area around the developing opening is stained and adheres to an operator during maintenance.

In order to avoid such a problem, in a conventional image forming apparatus, a suction port 3 is formed in a developing device 2 arranged around an image carrier 1 as shown in FIG. A toner scattering prevention device 7 in which a filter case 6 having a fan 4 and a filter 5 is attached to the suction port 3.
Some are provided.

In this toner scattering prevention device 7,
By driving the fan 4, the air in the developing device 2 is discharged from the suction port 3 through the exhaust path 8, thereby creating a flow of air that enters the developing device 2 through the developing opening 2 a of the developing device 2, and from the developing opening 2 a. While the toner is scattered, the filter 5 collects the toner from the discharged air. (See JP-A-10-3220)

[0005]

However, in such a conventional toner scattering prevention device 7, the collected toner adheres to the filter 5 and accumulates on the filter 5, causing clogging and weak suction airflow. Therefore, there is a problem that the effect of preventing toner scattering is not achieved.

Further, the toner accumulated on the filter 5 eventually falls into a large lump from the suction port 3 into the developing device 2, and adheres to the image carrier 1, causing density unevenness in the toner image. There was a problem that the quality deteriorated.

SUMMARY OF THE INVENTION It is, therefore, a first object of the present invention to provide a toner scattering preventing device which can continuously exert a toner scattering preventing effect and which does not cause a deterioration in image quality.

A second object of the present invention is to solve the first object by providing a toner scattering prevention device having an exhaust means, a toner collecting means, and a toner storing means, and particularly a layout of the toner storing means. An object of the present invention is to increase the degree of freedom and facilitate the attachment / detachment of the toner storing means.

A third object of the present invention is to solve the first object by providing a toner scattering prevention device having an exhaust means, a toner collecting means and a toner storing means, in particular, limiting the type of the exhaust means. Is to make it unnecessary.

A fourth object of the present invention is to solve the first object by providing a toner scattering prevention device having an exhaust means, a toner collecting means, and a toner storing means, wherein the toner collected by the toner collecting means is provided. Is to make the processing easier.

A fifth object of the present invention is to solve the first object by providing a toner scattering prevention device having an exhaust means, a toner collecting means, and a toner storing means, in which toner is reliably collected by the toner collecting means. To be able to collect.

A sixth object of the present invention is to solve the first object by providing a toner scattering prevention device having an exhaust means, a toner collecting means and a toner storing means, in which a toner which has just been replenished into a developing device is provided. Is to be sucked from the suction port and not immediately discharged through the exhaust path.

A seventh object of the present invention is to provide an image forming apparatus having a toner scattering prevention device which solves the above problems.

An eighth object of the present invention is to solve the seventh problem, and in an image forming apparatus having a toner scattering prevention device, it is possible to recycle the toner collected by the toner scattering prevention device, thereby reducing maintenance costs. Is to reduce.

[0015]

According to the first aspect of the present invention, in order to solve the above-mentioned first problem, a latent image on an image carrier is made visible by attaching toner with a developing device. Exhaust means for exhausting air in the developing device through an exhaust path in the toner scattering prevention device in the image forming apparatus,
A toner collecting means for collecting the toner from the air discharged by the exhaust means, and the toner collected by the toner collecting means located upstream of the toner collecting means falls into the toner of the developing device And a toner storing means for storing the toner without the toner.

According to a second aspect of the present invention, in order to solve the above-mentioned second problem, the toner scattering prevention apparatus according to the first aspect further comprises a toner storage means provided downstream of the exhaust means. Features.

According to a third aspect of the present invention, in order to solve the third problem, in the toner scattering prevention apparatus according to the first aspect, a toner storage means is provided upstream of the exhaust means. Features.

According to a fourth aspect of the present invention, in order to solve the fourth problem, in the toner scattering prevention apparatus according to any one of the first to third aspects, the toner storing means is detachable. It is characterized by the following.

According to a fifth aspect of the present invention, in order to solve the fifth problem, in the toner scattering prevention apparatus according to any one of the first to fourth aspects, expanded porous PTFE is used as a toner collecting means. Characterized by using

According to a sixth aspect of the present invention, there is provided a toner scattering prevention apparatus according to any one of the first to fifth aspects, wherein the toner is supplied to the developing device. The suction port of the exhaust path is provided on both sides of the supply area.

According to a seventh aspect of the present invention, in order to solve the seventh problem, an image forming apparatus includes the toner scattering preventing device according to any one of the first to sixth aspects. It is characterized by.

According to an eighth aspect of the present invention, in order to solve the eighth problem, in the image forming apparatus according to the seventh aspect, the toner stored in the toner storing means is returned to the developing device and reused. A toner recycling unit.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a laser copying machine provided with a toner scattering prevention device according to the present invention,
The overall schematic structure of the copying machine internal mechanism is shown. In FIG.
The partial enlarged configuration of the main part is shown.

Reference numeral 10 in the figure denotes an image forming apparatus main body. A drum-shaped image carrier 12 is provided in the apparatus main body 10. Around the image carrier 12, a charging device 13, a developing device 14, a transfer / transport device 15, a cleaning device 1
6. Discharge device 17 and the like are arranged.

On top of them, a laser writing device 18
Is provided. The laser writing device 18 includes a light source 20 such as a laser diode, a rotating polygon mirror 21 for scanning, a polygon motor 22, a scanning optical system 23 such as an fθ lens, and the like.

A fixing device 25 is disposed on the left side of the cleaning device 16 in the drawing. The fixing device 25 includes a fixing roller 26 having a built-in heater, and a pressure roller 27 pressing the fixing roller 26 from below.

A document reading device 30 is provided at an upper portion in the apparatus main body 10. The document reading device 30 includes a light source 3
1, a plurality of mirrors 32, an imaging lens 33, an image sensor 34 such as a CCD, and the like are provided.

On the other hand, a double-sided unit 35 is provided at a lower portion in the apparatus main body 10. A re-feeding path 37 is provided from the duplex unit 35 to a sheet feeding path 36 extending below the image carrier 12. The reversing path 39 is formed in the duplex unit 35 by branching from the middle of the sheet discharge path 38 extending from the exit of the fixing device 25.

A contact glass 40 is provided on the upper surface of the apparatus main body 10. The contact glass 4
An automatic document feeder 41 is mounted on the apparatus main body 10 so as to be openable and closable so as to cover 0.

Incidentally, the image forming apparatus main body 10 as described above is mounted on a paper feed table 43. In the paper feed table 43, paper feed cassettes 44 are provided in multiple stages. Each paper feed cassette 44 has a paper feed roller 4 corresponding thereto.
5 is provided. The feed roller 45 feeds the fed sheet,
The sheet is put in a transport path 46 that leads to a paper feed path 36. Transport path 46
Is provided with a plurality of pairs of transport rollers 47.

When making a copy using this laser copying machine, the original is set on the automatic document feeder 41, or the original is set directly on the contact glass 40 by opening the automatic document feeder 41. I do. Then, by pressing a start switch (not shown), the automatic document feeder 41 is driven, and the original conveyed onto the contact glass 40 or the original set on the contact glass 40 in advance is scanned by the original reading device 30 as a pixel. Read in units.

At the same time, a suitable paper feed roller 45 is rotated,
The sheet is fed out from a corresponding one of the plurality of paper cassettes in the plurality of paper cassettes in the paper table 43,
, And is conveyed by a conveying roller 47, and is fed into a paper feed path 36, where it abuts against a registration roller 48 and is stopped. Then, the registration roller 48 is rotated in synchronization with the rotation of the image carrier 12, and is sent below the image carrier 12.

On the other hand, when a start switch (not shown) is pressed, the image carrier 12 is simultaneously rotated clockwise in the figure.
With the rotation of the image carrier 12, the charging device 13 first uniformly charges the surface, and then irradiates a laser beam L in accordance with the read content read by the above-described document reading device 30 to irradiate the laser writing device 18 with the laser light L. To form an electrostatic latent image on the surface of the image carrier 12, and then the developing device 1
At step 4, toner is adhered to visualize the electrostatic latent image.

Then, the visible image is transferred by the transfer / conveyance device 15 onto the sheet fed below the image carrier 12 as described above. After transfer of the image, the surface of the image carrier 12 is cleaned by removing the residual toner with the cleaning device 16, the charge is removed by the charge removing device 17, and the image is prepared for the subsequent image formation.

On the other hand, the sheet after the image transfer is conveyed by the transfer / conveyance device 15 and enters the fixing device 25 where the fixing roller 2
6 and the pressure roller 27 apply heat and pressure to fix the transferred image. Thereafter, the sheet is discharged onto a tray (not shown) attached to the apparatus main body 10 through the sheet discharge path 38, for example.

When recording is also performed on the back side of a sheet using this copying machine, after recording on one side, the recording sheet is put into the duplex unit 35 through the reversing path 39, where it is reversed and again moved below the image carrier 12. Then, the image formed on the image carrier 12 is transferred to the rear surface in the same manner, and then discharged onto, for example, a tray (not shown).

Incidentally, the developing device 14 described above is
As can be seen from FIG.

In the developing tank 50, the first developing roller 5
First, a second developing roller 52, a paddle wheel 53, a stirring roller 54, a conveying screw 55, a separator 56, a doctor blade 57, a toner density sensor 58, and the like are provided in a developing case 59. Then, in the developing case 59, a two-component developer including a carrier and a toner is stored.

In the developing hopper 60, a gear-shaped toner supply member 61, a supply control plate 62, an agitator 63 and the like are provided. The developing hopper 60 contains toner.

In the developing device 14, the two-component developer in the developing case 59 is agitated by the rotation of the agitating roller 54 to be frictionally charged, and is flipped up by the rotation of the paddle wheel 53. The first developing roller 51 and the second developing roller 52 are attracted by the magnet in the second developing roller 52.

The developer adsorbed on the first developing roller 51 and the second developing roller 52 is removed from the first developing roller 51.
And after being conveyed by a sleeve on the outer periphery of the second developing roller 52 and scraping off the excess by the doctor blade 57,
The electrostatic latent image adheres to the image carrier 12 by the developing bias and is developed on the image carrier 12.

In the developing device 14, the image carrier 1
When the toner adheres to No. 2 and the toner is consumed, the ratio (toner density) decreases. Therefore, when the toner concentration in the developer becomes a predetermined value or less with respect to the target value of the toner concentration, the agitator 63 is rotated to agitate the toner and transport the toner to the toner replenishing member 61. Then, the supply regulating plate 62 is swung to supply the toner from the developing hopper 60 into the developing tank 50 to maintain the toner concentration in the developer.

The toner concentration in the developer is determined by
Is measured by a toner density sensor 58 attached to the printer. The target value of the toner density is set by a value obtained by measuring a measurement toner image (P pattern) formed on the image carrier 12 with a photosensor.

In general, there is often no image on both sides of the sheet. Therefore, the toner is replenished from the developing hopper 60 in the range of the toner replenishment area b excluding both sides so that the amount of toner on both sides does not increase.

By the way, as described above, the image carrier 12
The toner attached to the sheet is electrostatically transferred to a sheet by the transfer / transport device 15. However, about 10% of the toner remains untransferred on the image carrier 12. The untransferred toner remaining on the image carrier 12 is scraped off the image carrier 12 by a cleaning blade 65 and a brush roller 66 provided in the cleaning device 16.

The image carrier 1 is cleaned by the cleaning device 16.
2 the toner scraped off from above
6 enters the collection tank 67. And the collection screw 6
By 8, it is conveyed to one side of the cleaning device 16, discharged from a discharge port (not shown), and guided to the toner recycling device.

As shown in FIG. 1, the illustrated laser copying machine is provided with a toner scattering preventing device 70 connected to the developing device 14. The toner scattering prevention device 70 is connected to the developing device 14 by an intake tube 71 and includes an exhaust unit 72 in the apparatus main body 10, and is connected to the exhaust unit 72 by an exhaust tube 73 to Is provided with a toner storing means 74.

At the tip of the suction tube 71, a suction duct 75 is attached as shown in FIG. Suction duct 75
Has a connection port 76 for connecting one end of the intake tube 71 at the center of the upper surface, and has a large opening 77 on the lower surface as shown in FIG. However, a sheet member 78 such as a mylar is adhered to the lower surface thereof in correspondence with the toner supply area b of the developing hopper 60 to close the center of the opening 77,
Suction ports 79 are provided on both sides. A seal member 80 is attached around the opening 77 except for the side of the developing hopper 60.

As shown in FIG. 2, both ends of the suction duct 75 are inserted into guide grooves 82 provided on both sides of the developing case 59 so as to face each other in the direction indicated by an arrow.
9 is attached to the opening 83, and then the developing hopper 60 is attached to the developing tank 50 to prevent the developing tank 50 from coming off. A seal member 84 for sealing between the developing hopper 60 and the suction duct 75 is attached. Thus, the opening 83 of the developing case 59 is completely closed.

Next, as shown in FIG. 5, the exhaust means 72 shown in FIG.
1 and the other end of the exhaust tube 73 to the exhaust port 88. The eccentric pin 91 attached to the drive shaft 90 of the motor 89 is fitted to a part 93 of the rubber member 92.

Then, the motor 89 is driven in conjunction with a developing motor (not shown), and the center of the rubber member 92 reciprocates in the direction of the arrow in FIG. The illustrated exhaust valve is closed, air in the developing device 14 is sucked through the suction port 79 of the suction duct 75 described above, and is introduced into the pump 86 from the intake port 87 through the exhaust path in the intake tube 71, or the intake valve is closed. The exhaust valve is opened, and the air in the pump 86 is sent to the toner storing means 74 through the exhaust path of the exhaust tube 73.

In this manner, when the developing device 14 is operating, the air in the developing device 14 is sucked by the toner scattering prevention device 70 by always driving the exhaust means 72, so that the floating in the developing device 14 is achieved. In addition to sucking the toner, a suction airflow is generated in the developing opening 95 of the developing case 59 shown in FIG. 2, and for example, the surrounding air is sucked as shown by an arrow a in FIG. Can be prevented.

Even if the toner scattering prevention device 70 is not provided,
The rotation of the developing rollers 50 and 51 generates an airflow that sucks the surrounding air from the developing opening 95. However, by providing the toner scattering prevention device 70, more air is sucked and the toner scattering from the developing device 14 is further prevented. be able to.

As shown in FIG. 7, the toner storing means 74 is a tank 97 having a width and a height and a small depth, and as shown in FIG.
Along the outside. One side of the upper surface has an inlet 98 for connecting the other end of the exhaust tube 73, and the outer surface has an opening at a slightly higher position. Then, a large filter-shaped toner collecting means 100 is attached to the tank 97, and the opening is closed by the toner collecting means 100.

The toner collecting means 100 is obtained by stretching PTFE (polytetrafluoroethylene) having the highest scientific stability among fluororesins by a special technique to have a fine continuous porous structure. Air is allowed to pass, but toner is collected and stored in the tank 97.

When the expanded porous PTFE is used as the toner collecting means 100 as described above, unlike other filters such as an electrostatic filter, there is no toner leakage even when air is applied while applying pressure, and the toner is reliably removed. Can be collected.

Thus, the air sent from the exhaust means 72 through the exhaust tube 73 is transferred to the toner storing means 74.
The toner is collected by a toner collecting means 100, the collected toner is stored in a tank 97, and the air after the collection of the toner is discharged to the outside of the apparatus main body 10 through an exhaust grill.

The toner storing means 74 is provided with a toner full detecting means (not shown) for detecting the toner full state. When the toner is full, the toner in the tank 97 is discarded or the tank 97 is replaced with a new one.

Of course, the toner storing means 74 is not limited to the shape as shown in FIG.
The shape shown in FIG. Further, the opening of the tank 97 and the toner collecting means 100 for closing the opening are
It is better to be as large as possible so that clogging does not occur. In FIG. 8, the reference numerals used for the corresponding parts in FIG. 7 are used as they are, and redundant description thereof will be omitted.

In the example described above, the intake tube 71
Although the exhaust passage is formed using the exhaust tube 73 and the exhaust tube 73, the exhaust passage may be formed using a pipe or the like without being limited to the tube.

Incidentally, in the illustrated example described above, the toner storing means 74 and the toner collecting means 100 are provided downstream of the exhaust means 72. However, for example, as shown in FIG. 9, a toner storing unit 74 and a toner collecting unit 100 may be provided at a position upstream of the exhaust unit 72.

In the illustrated example, the toner collected by the toner collecting means 100 is received by the tray-shaped toner storing means 74 without falling into the toner of the developing device 14. The toner storing means 74 is detachable so that the stored toner can be discarded,
The processing of the toner collected by the toner collecting means 100 is facilitated.

In this way, the toner collecting means 100
The toner collected in the step (a) can be stored in the upstream toner storage means 74 so that the toner does not reach the downstream exhaust means 72. Therefore, the type of the exhaust means 72 is not required. Evacuation means 72 used
However, the exhaust means 72 is optimally used in consideration of the price, size, ease of assembly, and the like.

Further, the toner recycling means 110 may be provided as shown in FIG. 10, for example, without discarding the toner. Illustrated toner recycling means 11
0, a recess 104 in which the toner to be stored is formed in the toner storage means 74, and a toner conveying member 105 such as a screw for moving the toner to one side is provided in the recess 104;
The toner brought to one side is returned to the developing device 14, for example.
A toner collecting member 106 using a screw, a belt, a coil, or the like is provided.

When the toner recycling means 110 is provided,
The toner collected by the toner collecting means 100 can be recycled and used, and maintenance costs can be reduced.

[0066]

As described above, according to the first aspect of the present invention, the exhaust means for discharging the air in the developing device through the exhaust path, and the toner is collected from the air discharged by the exhaust means. The toner collecting means includes a toner collecting means and a toner storing means which is located upstream of the toner collecting means and stores the toner collected by the toner collecting means without falling into the toner of the developing device. The toner collected by the collecting means is stored in the toner storing means, and the toner scattering prevention effect can be continuously exhibited without causing clogging or the like.

Further, it is possible to provide a toner scattering preventing device which does not cause a drop in image quality by preventing the toner collected by the toner collecting means from falling into the toner of the developing device.

According to the invention described in claim 2, according to claim 1
In order to achieve the effect of the invention described in (1), in the toner scattering prevention device including the exhaust unit, the toner collecting unit, and the toner storing unit, the arrangement of the exhaust unit is considered because the toner storing unit is provided downstream of the exhaust unit. In addition, the toner storage means can be freely arranged, the degree of freedom in layout can be increased, and the attachment and detachment of the toner storage means can be facilitated.

According to the third aspect of the present invention, a first aspect is provided.
In order to achieve the effect of the invention described in (1), in a toner scattering prevention device including an exhaust unit, a toner collecting unit, and a toner storing unit, a toner storing unit is provided upstream of the exhaust unit. Storing the toner in the upstream toner storage means so that the toner does not reach the downstream exhaust means, and it is not particularly necessary to limit the type of the exhaust means,
The most suitable one can be used in consideration of price, size, ease of assembly, and the like.

According to the fourth aspect of the present invention, the first aspect is provided.
In order to achieve the effects of the invention described in (1), in the toner scattering prevention device including the exhaust means, the toner collecting means, and the toner storing means, since the toner storing means is detachable, the toner collected by the toner collecting means Can be easily performed.

According to the invention set forth in claim 5, according to claim 1,
In order to achieve the effects of the invention described in (1), in a toner scattering prevention device provided with an exhaust unit, a toner collecting unit, and a toner storing unit, since expanded porous PTFE is used as the toner collecting unit, the pressure is increased while applying pressure. Expanded porous PTFE
Even if air is passed through the filter, there is no toner leakage unlike other filters such as an electrostatic filter, and the toner can be reliably collected.

According to the sixth aspect of the present invention, the suction port of the exhaust path is provided on both sides of the toner supply area for supplying the toner into the developing device. It can be sucked and not immediately discharged through the exhaust path.

According to the invention of claim 7, according to claim 1,
Since the image forming apparatus includes the toner scattering prevention device according to any one of the first to sixth aspects, it is possible to provide an image forming apparatus including the toner scattering prevention device having the above-described effects.

According to the invention described in claim 8, such an image forming apparatus is provided with a toner recycling means for returning the toner stored in the toner storing means to the developing device and reusing it. The collected toner can be recycled and the maintenance cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a laser copier including a toner scattering prevention device according to the present invention, and is an overall schematic configuration diagram of an internal mechanism of the copier.

FIG. 2 is a partially enlarged configuration diagram of a main part thereof.

FIG. 3 is a perspective view of a suction duct attached to a distal end of an intake tube, which constitutes the toner scattering prevention device.

FIG. 4 is a perspective view of the intake duct viewed from a lower surface side.

FIG. 5 is an exploded perspective view of an exhaust unit constituting the toner scattering prevention device.

FIG. 6 is a partially enlarged perspective view of the vicinity of a developing opening of a developing device in the laser copying machine.

FIG. 7 is a perspective view of a toner storing unit included in the toner scattering prevention device.

FIG. 8 is a perspective view of another example of the toner storing unit.

FIG. 9 is a configuration diagram of another example of the toner scattering prevention device used in the developing device.

FIG. 10 is a configuration diagram of still another example of the toner scattering prevention device.

FIG. 11 is a configuration diagram of a toner scattering prevention device used in a conventional developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Image forming apparatus main body 12 Image carrier 14 Developing device 59 Developing case 70 Toner scattering prevention device 71 Intake tube 72 Exhaust means 73 Exhaust tube 74 Toner storage means 75 Suction duct 79 Suction port 86 Pump 95 Development opening 97 Tank 100 Toner collection Means 102 Fan 104 Concave part 105 Toner transport member 106 Toner recovery member 110 Toner recycling means b Toner supply area

Claims (8)

[Claims] 1. An image forming apparatus for visualizing a latent image on an image carrier by attaching toner in a developing device, comprising: an exhaust unit for exhausting air in the developing device through an exhaust path; A toner collecting means for collecting the toner from the air discharged by the toner collecting means, and the toner collected by the toner collecting means positioned upstream of the toner collecting means without falling into the toner of the developing device. A toner scattering prevention device, comprising: a toner storing means for storing. 2. The toner scattering prevention device according to claim 1, further comprising the toner storage unit downstream of the exhaust unit. 3. The toner scattering prevention device according to claim 1, further comprising the toner storage unit upstream of the exhaust unit. 4. The toner scattering prevention device according to claim 1, wherein said toner storing means is detachable. 5. An expanded porous P as the toner collecting means.
5. The method according to claim 1, wherein TFE is used.
3. The toner scattering prevention device according to 1. 6. The toner scattering prevention device according to claim 1, wherein suction ports of the exhaust path are provided on both sides of a toner supply area for supplying toner into the developing device. 7. An image forming apparatus comprising the toner scattering prevention device according to claim 1. 8. The image forming apparatus according to claim 7, further comprising a toner recycling unit that returns the toner stored in the toner storage unit to the developing device and reuses the toner.