JP2001209290A - Recovery toner transport device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recovery toner transport device which can transport toner efficiently, without leaving recovery toner in a cleaning unit. SOLUTION: The angle θ to the vertical direction of a scraper 26 which abuts on the free end on the magnet roller 24 which collects and transports toner from the surface of a photosensitive drum 11 is set at a angle below the angle of repose of the magnetic toner transported. The toner which is not transported by the magnetism of the magnet roller 24 falls by the dead weight by the inclination of the scraper 26, is again caught and transported by the magnetism of the magnet roller 24, and does not remain in the cleaning unit 13.

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 using an electrophotographic method, such as a copying machine, a printer, a facsimile, and the like, and more particularly, to a collected toner conveying device for collecting and reusing transfer residual toner.

[0002]

2. Description of the Related Art In recent years,
As a countermeasure against environmental pollution caused by collected toner, an electronic image forming system for reusing toner has been increasing. This means that after transferring a developed image from an image carrier such as a photoconductor to a transfer sheet, the toner remaining on the photoconductor is collected by a removing means such as a cleaning blade, and then returned to the developing device and reused. It is assumed that.

[0003] As a device for transporting such collected toner,
Metal thickness of 0.3 to 0.3 mm
A member obtained by winding a sheet metal of 0.5 mm in a spring coil shape has been generally used. This coil prevents the collected toner, whose cohesion degree has deteriorated, from adhering to itself or forming a bridge due to self-vibration during rotational conveyance, and maintains a stable conveyance force both initially and over time. Is what you can do.

However, in this transport system, the toner powder is transported while being packed on the outer wall of the transport path when transporting the toner. Therefore, if a part of the outer wall is a weak member such as a seal member,
There is a problem that the air blows out from the gap between the seal members. This is conspicuous in an apparatus having a configuration for vertically transferring transfer paper as shown in FIG. 1 which has recently been increasing in number because of the ease of removing jammed paper.

In the image forming apparatus having such a configuration, the cleaning device is disposed above the photosensitive drum serving as the image carrier due to layout restrictions. However, in this structure, the collected toner collected at the edge of the cleaning blade does not fall due to gravity, and thus stays on the scraped photosensitive drum as it is. Inevitably, the seal members at both ends of the cleaning blade are arranged in the toner conveying path. For this reason, in the toner conveying method using a conveying member such as a coil spring or a screw, there is a problem that the toner is pushed into the conveying member such as the conveying coil, and the toner blows out from a gap of the seal portion in the middle of the conveying path. Was.

That is, the transfer means using a coil or a screw is a method in which the outer wall around the transfer means is fixed, and the powder is transferred while being pressed against the outer wall. Therefore, a part of the outer wall is covered with the seal as described above. In this configuration, the pressure of the toner powder acts intensively on the gap between the seals, so that the toner easily blows out and easily pollutes the inside of the apparatus. As a result, there is a case where the edge of the cleaning blade is pushed up with time and cleaning failure occurs.

[0007] In order to prevent this, a mechanism for constantly discharging toner from near the edge is required. An ideal function required of such a toner collecting device is that the conveying member can be arranged as close as possible to the vicinity of the edge of the cleaning blade, and can convey while pulling in the toner immediately after being scraped from the photosensitive drum. The closer the transport member is to the edge of the cleaning blade, the higher the cleaning and transport effect. Therefore, even if the transport member interferes with the edge of the cleaning blade, it must be such that the edge made of urethane rubber or the like is not damaged. That is, it is not desirable that the conveying member has a hard member rotating on the surface,
When the cleaning device is arranged above the photosensitive drum having a small diameter of 30 mm or less, the space is greatly restricted and space saving is required.

As a solution to this problem, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 5392 and Japanese Patent Application Laid-Open No. 8-95456, a magnetic roller is disposed upstream of a blade to collect magnetic toner. However, the former does not mean collecting and reusing toner.
The only effect is to prevent toner scattering.
The collected toner could not be transported in a direction parallel to the blade ridgeline, and was intended only to prevent toner scattering.

The applicant of the present invention has already proposed a technique for solving the above-mentioned problem, in which the recovered toner is conveyed by a spirally magnetized magnet roller and a scraper in contact with the magnet roller.

FIG. 1 is a schematic configuration diagram of an image forming apparatus provided with the above-described transfer paper vertical transport mechanism and the toner recycling mechanism. This image forming apparatus cleans the surface of the photosensitive drum 11 by rubbing against the charging roller 12 as a contact charging rotator that rotates in contact with the surface of the photosensitive drum 11 as an image carrier. In addition to the cleaning unit 13, the transfer unit 14 further includes a transfer roller 14. The transfer sheet P is conveyed from a sheet tray 15 by a sheet feed roller 16, and the developed image on the photosensitive drum 11 is transferred to the transfer sheet P at the same time.

The photosensitive drum 11 is an image carrier having a photoconductive layer such as an OPC, and rotates counterclockwise in the drawing during an image forming operation. A high voltage is applied to the charging roller 12 at the time of image formation, and the surface of the photosensitive drum 11 is uniformly charged and charged. Then, the negative charge on the photosensitive drum 11 is erased by the laser beam from the writing device 17 to form an electrostatic latent image.

In the drawing, reference numeral 18 denotes a developing device, in which toner and carrier are accommodated.
The rotation of 9 causes the toner to adhere to the surface of the image bearing member on the photosensitive drum 11 and visualizes the electrostatic latent image formed thereon. The toner is supplied from a toner supply unit (not shown) while the density is controlled by the T sensor 20 and the P sensor 21. The toner is a magnetic toner.

On the other hand, the transfer paper P, which has been transported to the registration roller 22 and is on standby, is sent out by the registration roller 22 in synchronism with the image on the photosensitive drum 11. A transfer bias is applied to the transfer roller 14 at the same time that the leading end of the transfer paper P enters the nip portion with the photosensitive drum 11, and a charge having a polarity opposite to that of the toner on the photosensitive drum 11 is applied to the transfer roller 14. Transfer is performed.
In the drawing, reference numeral 23 denotes a static elimination needle for neutralizing the transfer paper P.

The photosensitive drum 11 is not transferred to the transfer paper P.
The magnetic toner remaining on the photosensitive drum 11 is separated from the photosensitive drum 11 by a conveying member having a magnetic force, that is, a magnet roller 24 and a blade 25, adheres to the conveying member 24 with a magnetic force, and is stopped by a scraper 26 abutting on the conveying member 24. While being conveyed along the longitudinal direction of the photoconductor drum 11 from the back to the front in the vertical direction with respect to the paper surface of FIG.
Reused. Finally, the photosensitive drum 11 is recharged at the same time as the residual charge is erased by the charge eliminating lamp (QL) 28, and prepares for the next print.

FIG. 2 shows a magnetization pattern of the magnet roller 24. The magnet roller 24 is driven to rotate counterclockwise in FIG. 3 from a gear integrated with a flange of the photosensitive drum 11 via an idler gear. Illustration of each drive element is omitted. The magnet roller 24 has a right-handed spiral magnetized pattern and has 4 to 8 poles. In the illustrated example, there are six poles, and the pitch at which the six poles make a round on the cylinder of the magnet roller 24 is 36 mm. The magnet roller 24 includes, for example, BQG manufactured by TDK Corporation.
14 (Surface maximum magnetic flux density 50-60 mT (500-60
0G), rubber thickness t = 1.5, outer diameter φ9 mm). The scraper 26 has, for example, a thickness t = 0.05.
Use 0.2 mm PETP or the like.

FIG. 3 is an enlarged sectional view showing the cleaning unit 13 of the above-described apparatus and its vicinity. The magnetic toner attracted to the magnet roller 24 and scraped off by the scraper 26 is mainly conveyed through the portion A in FIG. 3, but the unconveyed toner remains around it as shown in B in FIG. Would be. On the other hand, if the wall 29 is provided at the position shown in FIG. 4, the toner will be pushed into the portion C, and there is a disadvantage that toner aggregation and image deterioration are caused. If the collected toner is returned to the developing device 18 and reused, there is a problem that an image is deteriorated due to too much stress.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a collected toner conveying device capable of efficiently conveying toner without leaving the collected toner in the cleaning unit.

Another object of the present invention is to provide a collected toner conveying device capable of preventing the blade edge from being damaged due to insufficient toner input to the cleaning blade.

Further, according to the present invention, the toner can be efficiently conveyed without leaving the toner in the cleaning device while preventing the magnet roller from being damaged by the sliding of the magnet roller and the scraper, and preventing the scraper from being turned up. It is an object of the present invention to provide a collected toner conveying device that can perform the above operation.

Still another object of the present invention is to provide a collected toner conveying device which can apply a small stress to the conveyed toner and can prevent image deterioration when the collected toner is reused.

[0021]

According to a first aspect of the present invention, there is provided a recovered toner conveying apparatus, comprising: a cleaning unit for removing magnetic toner remaining on an image carrier; The recovered toner conveying device, comprising: a cylindrical rotating member having a helically magnetized pattern provided upstream of the image carrier in the rotation direction; and a member abutting in parallel with a rotation axis of the rotating member. The inclination of the member with respect to the vertical direction is smaller than the angle of repose of the toner.

According to a second aspect of the present invention, in order to achieve the above object, the rotating direction of the rotating member is set to a counter direction with respect to the image carrier.

According to a third aspect of the present invention, in order to achieve the above-mentioned object, the rotating direction of the rotating member is set to the direction of rotation with the image carrier.

According to a fourth aspect of the present invention, to achieve the above object, a cleaning means for removing magnetic toner remaining on the image carrier, and a cleaning means provided upstream of the cleaning means in the rotation direction of the image carrier. The recovered toner conveying device, comprising: a cylindrical rotary member having a helical magnetic force; and a coating member that covers the rotary member and partially extends parallel to the rotation axis of the rotary member. Wherein the angle of the extending portion with respect to the vertical direction is smaller than the angle of repose of the toner.

According to a fifth aspect of the present invention, in order to achieve the above object, a cleaning means for removing magnetic toner remaining on the image carrier, and a cleaning means provided upstream of the cleaning means in the rotation direction of the image carrier. A toner conveying device having a cylindrical rotating member having a magnetic force in a spiral shape, and a covering member having a surface that covers a cylindrical surface of the rotating member and a part of which extends parallel to the rotation axis of the rotating member. In the apparatus, the surface of the covering member and the extending surface are connected by a curved surface having a curvature equal to or larger than the curvature of the toner particle diameter.

According to a sixth aspect of the present invention, in order to achieve the above object, the extension portion has a cylindrical shape which is coaxial with a rotation axis of the rotating member.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. In the following, portions common to the related art are denoted by the same reference numerals, and redundant description is omitted. FIG. 5 is an enlarged cross-sectional view corresponding to FIG. 3 showing the first embodiment of the recovered toner transport device according to the present invention. In the present embodiment, the relationship between the angle θ with respect to the vertical direction of the scraper 26 whose free end abuts on the magnet roller 24 and the angle of repose θa (14.8 °) of the magnetic toner to be conveyed is defined. That is, the angle θ of the scraper 26 with respect to the vertical direction
However, if the inclination is greater than the angle of repose, the toner does not fall down the inclination due to its own weight. Therefore, the angle θ of the scraper 26 with respect to the vertical direction is equal to or less than the angle of repose θa, for example, θ = 10 °.

As a result, the toner that has not been conveyed from the back of the drawing to the near side by the magnetic force of the magnet roller 24 falls by its own weight due to the inclination of the scraper 26, and is again captured by the magnetic force of the magnet roller 24 and conveyed. Therefore, it does not remain in the cleaning unit 13.

FIG. 6 is an enlarged sectional view corresponding to FIG. 3 showing a second embodiment of the recovered toner conveying device according to the present invention. In this embodiment, the rotation direction of the magnet roller 24 is
The photosensitive drum 11 is rotated in the forward direction, and the scraper 26 is rotated.
Are also reversed from the first embodiment. The angle θa of the scraper 26 with respect to the vertical direction is set to 10 °.
As a result, the toner that cannot be conveyed from the back of the paper to the front is again captured by the magnet roller 24,
What is not captured by the magnetic force further falls on the edge of the cleaning blade 25.

That is, in the case of the first embodiment, since the toner is always removed by the magnet roller 24, if the toner is removed too much, the toner input to the edge of the cleaning blade 25 becomes insufficient, and the edge may be damaged. However, by setting the rotation direction of the magnet roller 24 and the arrangement of the scraper 26 in this way, the possibility that the edge of the cleaning blade 25 is damaged is almost eliminated.

FIG. 7 is an enlarged sectional view corresponding to FIG. 5 showing a third embodiment of the recovered toner conveying device according to the present invention. In this embodiment, the magnet roller 24 is covered with the covering member 30, and the magnet roller 24 rotates inside the covering member 30. The covering member 30 is a resin member having a thickness t = 0.05 to 0.5 mm, such as PETP or POM, and has a cylindrical surface of the magnet roller 24 along the longitudinal direction (perpendicular to the plane of the drawing) as illustrated. And a part thereof extends along the rotation axis of the magnet roller 24 in parallel in the entire longitudinal direction. The extended portion 31 performs a function corresponding to the scraper 26 of the above embodiment. For this reason, the first and second
Unlike the embodiment, the surface of the magnet roller 24 and the scraper 26 do not slide directly, so there is no possibility that the surface of the magnet roller 24 is shaved, filmed with toner, or the scraper 26 is turned up. Disappears. Further, since the surface of the magnet roller 24 does not wear or film, the magnet roller 2
4 can be easily reused.

FIG. 8 is an enlarged cross-sectional view corresponding to FIG. 6, showing a fourth embodiment of the recovered toner conveying device according to the present invention. In this embodiment, the relationship between the rotation direction of the magnet roller 24 and the extension direction of the extension portion 31 is the same as that of the second embodiment, and the other configurations and operations are the same as those of the embodiment of FIG. Therefore, duplicate description will be omitted.

FIG. 9 is an enlarged cross-sectional view of a toner conveying portion in the third and fourth embodiments. In order to convey the toner without giving stress, it is better to increase the helical pitch of the magnetization of the magnet roller 24, or to increase the angle θb between the covering member 30 and the extending portion 31 to more than 90 °. Good, so that toner deterioration hardly occurs. Further, the joint between the covering member 30 and the extended portion 31 must have a radius of curvature larger than the curvature of the particle diameter of the toner to be conveyed.

With this configuration, as shown in FIG. 9, the toner is conveyed from the back side of the drawing to the front side while the toner circulates smoothly. When the radius of curvature of the joint between the covering member 30 and the extended portion 31 was set to 10 μm or more when the toner particle diameter was 7.5 μm, the toner could be smoothly transported.

FIG. 10 is an enlarged sectional view (A) and a perspective view (B) corresponding to FIG. 6, showing a fifth embodiment of the recovered toner conveying device according to the present invention. In this embodiment, a portion 32 extending from the surface of the covering member 30 is formed into a cylindrical shape as shown, and its free end is opened in the longitudinal direction. The opening width is a gap where the toner can be captured by the magnetic force of the magnet roller 24 and the toner does not drop.

However, as in the modification shown in FIG. 11, an entrance seal 33 made of a polyurethane rubber sheet is provided at the tip of the free end, and the toner on the surface of the covering member 30 passes through the entrance seal 33 without peeling. It is good also as a structure which makes contact with a belly by the pressure of about.

In FIG. 10, the extension 3
Although 2 is drawn very large, the size of the magnetic force of the magnet roller 24 is actually set to be large enough to efficiently transport the toner. The toner captured by the magnetic force of the magnet roller 24 is conveyed in the longitudinal direction while circulating in the extending portion 32 as shown in FIG.

[0038]

As described above, the recovered toner conveying device according to the present invention has a helically magnetized structure provided upstream of the cleaning means for removing the magnetic toner remaining on the image carrier in the image carrier rotation direction. A cylindrical rotating member having a pattern, and a member abutting in parallel with a rotation axis of the rotating member,
Since the inclination of the contact member with respect to the vertical direction is smaller than the angle of repose of the toner, the toner can be efficiently collected and transported without accumulating in the cleaning unit.

According to the third aspect of the present invention, as described above, the rotating direction of the rotating member is
In addition to the above-mentioned common effects, the toner that cannot be completely conveyed is appropriately supplied to the cleaning blade edge of the cleaning unit, so that the edge of the cleaning blade is damaged due to insufficient toner. There is an effect that can be prevented.

According to the fourth and sixth aspects of the present invention, as described above, the helical spiral provided upstream of the cleaning means for removing the magnetic toner remaining on the image carrier in the image carrier rotation direction. The angle with respect to the vertical direction of a cylindrical rotating member having a magnetic force and a portion of the member covering the rotating member, which extends in parallel with the rotation axis of the rotating member, is set to be smaller than the angle of repose of the toner. Therefore, in addition to the above-mentioned common effects, the rotating member and the scraper of the cleaning means can be prevented from directly contacting each other, and the effect of preventing wear of the rotating member, filming, and damage to the entrapment of the scraper can be prevented. is there.

According to the fifth and sixth aspects of the present invention, as described above, the spirally provided spirally provided upstream of the cleaning means for removing the magnetic toner remaining on the image carrier in the rotation direction of the image carrier. A cylindrical rotating member having a magnetic force, and a part of the member covering the cylindrical surface of the rotating member, which extends parallel to the rotation axis of the rotating member, and the surface of the covering member are set to be equal to or larger than the curvature of the toner particle diameter. In addition to the above common effects, the stress applied to the toner to be conveyed can be reduced, and the toner can be conveyed without being deteriorated by the stress. Is not deteriorated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus using a conventional collected toner conveying device.

FIG. 2 is a view showing a magnetization pattern of a toner conveying magnet roller used in the apparatus of FIG. 1;

FIG. 3 is an enlarged sectional view showing a cleaning unit of the apparatus shown in FIG. 1 and a portion in the vicinity thereof;

FIG. 4 is a cross-sectional view showing an example in which a defect in the example of FIG. 3 is dealt with.

FIG. 5 is an enlarged cross-sectional view corresponding to FIG. 3 showing the first embodiment of the recovered toner transport device according to the present invention.

FIG. 6 is an enlarged cross-sectional view corresponding to FIG. 3, showing a second embodiment of the recovered toner conveying device according to the present invention.

FIG. 7 is an enlarged cross-sectional view corresponding to FIG. 5, showing a third embodiment of the recovered toner transport device according to the present invention.

FIG. 8 is an enlarged cross-sectional view corresponding to FIG. 6, showing a fourth embodiment of the recovered toner conveying device according to the present invention.

FIG. 9 is an enlarged sectional view of a toner conveying portion in the embodiment of FIGS. 7 and 8;

FIG. 10 is an enlarged sectional view (A) and a perspective view (B) corresponding to FIG. 6, showing a fifth embodiment of the recovered toner conveying device according to the present invention.
It is.

FIG. 11 is a sectional view showing a modification of the embodiment of FIG. 10;

[Explanation of symbols]

 Reference Signs List 11 photosensitive drum 12 charging roller 13 cleaning unit 14 transfer roller 15 paper tray 16 paper feed roller 17 writing device 18 developing device 19 developing sleeve 20 T sensor 21 P sensor 22 registration roller 23 static elimination needle 24 magnet roller 25 blade 26 scraper 27 Conveying pipe 28 Static elimination lamp 29 Wall 30 Covering member 31 Extension part 32 Extension part 33 Inlet seal part P Transfer paper θ, θa Angle of scraper with respect to vertical direction θb Angle between coating member and extension part

Claims (6)

[Claims] A cleaning means for removing magnetic toner remaining on the image carrier; a cylindrical rotating member having a helical magnetization pattern provided upstream of the cleaning means in the rotation direction of the image carrier; And a member that abuts in parallel with the rotation axis of the rotating member.
A recovery toner conveying device wherein the inclination of the contact member with respect to the vertical direction is smaller than the angle of repose of the toner. 2. The recovered toner conveying device according to claim 1, wherein the rotating direction of the rotating member is set to a counter direction with respect to the image carrier. 3. The image forming apparatus according to claim 1, wherein the rotation direction of the rotation member is set to be a rotation direction along with the image carrier.
Collection toner transport device. 4. A cleaning means for removing magnetic toner remaining on an image carrier, a cylindrical rotary member having a helical magnetic force provided upstream of the cleaning means in the rotation direction of the image carrier, and In a recovered toner conveying device having a covering member that covers a member and a part of which extends parallel to a rotation axis of the rotating member, an angle of the covering member with respect to a vertical direction of the extending portion is set to a toner resting angle. A collected toner conveying device characterized by being smaller than a corner. 5. A cleaning means for removing magnetic toner remaining on the image carrier, a cylindrical rotary member having a helical magnetic force provided upstream of the cleaning means in the rotation direction of the image carrier, and In a toner conveying device having a covering member having a surface that covers a cylindrical surface of a member and a part of which extends parallel to a rotation axis of the rotating member,
A toner conveying device, wherein the surface of the covering member and the extending surface are connected by a curved surface having a curvature equal to or larger than a curvature of a toner particle diameter. 6. The apparatus according to claim 4, wherein the extending portion has a cylindrical shape coaxial with a rotation axis of the rotating member.
Or 5, the collected toner conveying device.