JPH0412379A - Developer supply device - Google Patents

Abstract

PURPOSE:To prevent the supply capacity of a developer by dropping and supplying the developer to the lower side of a rotary means by rotating the rotary means via a mesh, and removing developer powder blown up from the developer and attached on the lower plane of the mesh with a cleaning means. CONSTITUTION:The mesh 56, a powder developer housed on the mesh 56, the rotary means 55 rotating as connecting slidably with the upper plane of the mesh 56 and drops the developer to the lower side of the mesh 56, and the cleaning means 60 which removes toner attached on the lower plane of the mesh 56 are provided. The toner attached on the lower plane of the mesh 56 can be removed by the cleaning means 60. Thereby, it is possible to prevent the bridging of the toner on the lower plane of the mesh 56 occurring, which maintains the numerical aperture of the mesh 56 at a constant value, and stable supplies the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developer replenishing device for replenishing powder developer to a developing section in a developing device such as a copying machine.

[Conventional technology]

Conventionally, as the developer replenishing device, Japanese Patent Publication No. 401323
There are some methods proposed in Publication No. 1 and US Pat. No. 4,595,277.

The former (Japanese Patent Publication No. 40-13231) includes a developer tank that includes a developer storage section and a developer supply section, and a developer tank that is placed in the developer supply section and comes into contact with the developer supplied from the developer storage section. This device includes a rotating brush that rotates while rotating, and a slit that is appropriately provided on the circumferential surface of a developer tank that covers the rotating brush.

In this developer replenishment device, the developer held by the rotating brush is conveyed to the part facing the slit, and due to the contact between the rotating brush and the slit, the developer held between the brushes falls through the slit and is replenished below. Ru.

The latter (U.S. Pat. No. 4,595,277) covers the bottom of the toner hopper with an upwardly curved screen having a plurality of holes, and installs an agitator inside the toner hopper with a plurality of ronds around its periphery as the toner hopper rotates. The rod is provided to slide on the top surface of the screen.

In this developer replenishing device, the screen moves up and down as the agitator rotates, and toner is supplied falling through holes in the screen.

[Invention or problem to be solved]

However, these developer supply devices do not have a means for cleaning the developer tank constituting the slit or the lower surface of the screen.

Therefore, developer powder generated at a portion of the developer tank that receives developer supply through the slit or screen (for example, the developer mixing and stirring section) settles on the lower surface of the developer tank and screen, causing a crosslinking phenomenon. This has resulted in a problem in that the effective cross section of the slits and screen holes is reduced, and the ability to replenish developer is reduced.

It is true that in the case of the latter type in which a rod slides on the screen, some of the adhered toner falls off due to the vibration of the screen, but it cannot be completely removed.

[Means to solve the problem]

The present invention has been made to solve the above problems,
The developer replenishing device includes a mesh, a powder developer accommodated on the mesh, 111 a rotation means that rotates while slidingly contacting the upper surface of the mesh and drops the developer below the mesh, iv, the mesh/ A cleaning means for removing developer attached to the lower surface of the unit.

[Effect]

According to the above configuration, as the rotating means rotates, developer is dropped and replenished below the mesh through the mesh.

Developing particles that have fallen from the replenished developer and adhered to the lower surface of the mesh are removed by the cleaning means.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

A. Structure of Developing Device The developing device 1 shown in FIG.
It is composed of

Supply section 10 A supply chamber 11 of the supply section 10 is provided with a supply blade 12 . The supply blade 12 is constructed by side plates 14, 14 provided at both ends of a shaft 13, with a plurality of scooping plates 15 placed horizontally on the outer periphery thereof, and is rotatable in the direction of arrow a.

ii. Concentration Detection Section 26 The concentration detection section 20 is provided at the rear of the supply section 10 (on the left side in the figure), and a conveyance blade 22 is provided on a conveyance path 21 that is continuous with and parallel to the supply chamber 11.

As shown in FIG. 2, the conveying blade 22 has a scooping plate 24 at the center of a shaft 23, and a plurality of blades 25 on both sides of the scooping plate 24 at predetermined intervals. These blades 25 are attached at different angles on the left and right sides of the scooping plate 24, so that the conveying performance due to the rotation of the conveying blades is different between the left and right sides. That is, the second
In the figure, the left wing 25 has the ability to convey to the right side,
The right wing 25 has the ability to convey to the left. Further, the scooping plate 2 is provided on the wall 26 between the supply chamber 11 and the conveyance path 21.
An opening 27 is provided in the portion where 4 faces each other.

Furthermore, a toner concentration detection sensor 28 is provided at the center bottom of the conveyance path 21 to measure changes in magnetic permeability of the developer.
The sensor surface is approximately aligned with the bottom surface of the conveyance path 21.

11] Developing section 30 In the developing section 30, the cylindrical body 31 is made of a non-magnetic material,
It is arranged to face the photoreceptor 100 with a predetermined gap therebetween, and is configured to be rotated in the direction of arrow C about an axis (not shown). Further, the cylindrical body 31 is connected to a power source 32, and a predetermined bias voltage 8 is applied thereto.

The magnet body 33 has a plurality of magnetic poles (N, , N2.S, , N3.N4.S) extending in the axial direction of the cylindrical body 31.

N5. S3) are provided on the outer periphery in this order, magnetic poles N1 and N2 of the same polarity and magnetic poles N3 and N4 are adjacent to each other, and the intermediate areas thereof are designated as non-magnetic pole regions M, , M2, respectively, and then the cylindrical body 3
1, the non-magnetic pole region M;
is located above the opposing portion of the cylindrical body 31 and the photoreceptor 100, and the non-magnetic pole region M2 is located at the opposing portion of the supply vane 12.

The thin film member 34 is a thin-walled (0.2 mm thick) cylindrical body having a circumference slightly longer than the circumference of the cylindrical body 31.
It is packaged in 1. This thin film member 34 is made of nylon,
It is made of polyimide and polycarbonate, and carbon is added to give it electrical conductivity.

The regulating member 36 is attached to the upper part of the developer tank, and its tip is formed on the outer peripheral surface of the upper part of the cylindrical body 31 by a predetermined gap Dr3.
They are facing each other.

The leveling member 37 is attached to the developing tank via the regulating member 36, and its tip is opposed to the area near the area facing the non-magnetic pole area M1 of the thin film member 34 with a predetermined can knob DB2.

iv. Recovery section 40 The recovery section 40 is located above the supply section 10 and is partitioned from the supply section 10 by a partition wall 41. The front wall 42 of the partition wall 41 is formed with a predetermined distance from the cylindrical body 31, and its upper end A passage 43 is provided between the rear wall 44 of the partition wall 41 and the upper cover 29 of the concentration measurement section 20, and a drop path 45 leading to the supply chamber 11 is provided between the rear wall 44 of the partition wall 41 and the upper cover 29 of the concentration measuring section 20. In addition, the collection section 4
0 is provided with two sending blades 47 and 48 at the front and back, and are designed to rotate in the directions of arrows d and e, respectively.

v. Toner Replenishment Section 50 The toner replenishment section 50 is formed with a storage chamber 51 and a replenishment chamber 54 , and an opening is provided at the bottom of the replenishment chamber 54 so that this opening is located above the empty chamber 46 . be. Stirring blade 5
2.53 are respectively arranged in the storage chamber 51, and arrows f,
It is designed to rotate in the g direction. The brush roll 55 is provided with brushes around the shaft, and the supply chamber 54
It is arranged so that it is rotated in the direction of the arrow. Note that the supply chamber 5 facing the lower part of the brush roll 55
The housing of No. 4 has a curved surface so that it makes light contact with the tips of the brush bristles.

The mesh 56 is made of a mesh made of wires organized in a lattice shape or a plate-like material made of a thin plate with a large number of holes, and is arranged so as to close the bottom opening of the supply chamber 54, so that the ends of the flan bristles are placed on the upper surface of the mesh 56. Make sure to lightly slide them into contact. The flicker rod 57 is a region where the brush moves, and is provided parallel to the brush roll 55 on the upstream side of the mesh 56 with respect to the moving direction of the brush roll 55.

Further, the mesh 56 is movable in the horizontal direction in the figure, and as it moves, the lower surface of the mesh is cleaned by a mesh cleaning device 60.

As shown in FIGS. 4 to 6, this mesh cleaning device 60 includes a support base 61 provided below the mesh 56 and in an area outside the bottom opening of the supply chamber 54, and a support base 61 provided on the support base 61. A brush 62 with bristles that can be brought into contact with the lower surface of the mesh, a leaf spring 63 that biases the mesh 56 to the left at the right end in the figure, and a leaf spring 63 that is fixed to both ends of the shaft 53a of the stirring blade 53 and is attached to the mesh 56. It is composed of cams 64 and 64 that intermittently press the left end in the figure.

B Developing operation The developing operation will be explained.

A two-component developer consisting of toner and magnetic carrier is used, and is stored in the supply chamber 11. The developer is also magnetically attracted to the outer periphery of the thin film member 34, and the magnetic attraction force of the developer causes the surplus part of the thin film member 34, that is, the part longer than the circumference of the cylindrical body 31, to face the non-magnetic pole region M1. The bulge 35 is formed in a concentrated manner at a certain area, and the outer circumference of the bulge 35 is brought into contact with the outer periphery of the photoreceptor 100 . Note that the contact width α of the bulge 35 is wider than the width at which the developer contacts the photoreceptor in a magnetic brush type developing device, for example, 6 to 1
It is set to about 2 mm.

The developer in the supply chamber 11 is mixed by the surrounding scooping plate 15 based on the rotation of the supply blade 12, and the toner and carrier come into frictional contact and are charged to opposite polarities. Further, due to the conveying action of the scooping plate 15, a part of the developer is sent over the wall 26 to the concentration measuring section 20, and the developer scooped by the scooping plate 15 is transferred to the outer periphery of the thin film member 34 in the supply area P. supplied to the department. The developer scooped by the scooping plate I5 is regulated by a regulating member 49 consisting of a brush provided under the partition wall 41, and the supply amount is adjusted to be constant. Once upon a time, Fall Road 4
Even if the developer with a relatively high toner concentration supplied from 5 lands on the developer on the scooping plate 15, this high concentration developer is scraped off by the regulating member 49 and is not sent directly to the supply area P. do not have.

The developer sent to the concentration measuring section 20 is conveyed toward the center by the blades 25 as the conveying blade 22 rotates, and then merges and mixes at the center, and is scooped up by a scooping plate 24 and sent to the supply chamber 11. be returned.

The developer sent back to the supply chamber 1N is dispersed left and right by the mixing and stirring action of the supply blades 12. In addition, as shown in FIG. 2, two blades 16.1 are provided at the center of the supply blade 12.
6 and set their respective angles with respect to the shaft 13 to be opposite, the developer sent back from the conveyance path 21 is actively distributed to the left and right, and the developer sent back from the left side of the conveyance path 21 is A part of the developer sent back from the right side of the conveyance path 21 is conveyed to the left side of the supply chamber 11, so that the left and right developers are mixed, and the developer is mixed with the left side or the right side. There is no inconvenience that the toner concentration (weight mixing ratio of toner to carrier) of only the developer decreases.

Further, the toner concentration of the developer is measured by a toner concentration detection sensor 28 located at the center. The toner concentration measured here is
Since this relates to a mixture of the developer sent by the left and right blades, the detected value is an average value, and the detected value does not vary greatly due to a local decrease in toner concentration. Therefore, stable toner concentration management is possible.

On the other hand, the developer held on the outer periphery of the thin film member 34 in the supply area P is held based on the magnetic attraction J of the magnet 33 and is conveyed in the direction of arrow C by the rotation of the cylindrical body 31. regulated by.

The developer regulated by the regulating member 36 passes through the passage 43 and is collected by the collecting section 40 . Therefore, the developer does not remain indefinitely in front of the regulating member 36 and is not subjected to stress, and deterioration of the developer is reduced.

As shown in FIG. 3, the developer that has passed through the tip of the regulating member 36 passes through the magnetic pole N5. S3. It is conveyed in the state of a magnetic brush by the opposing part of N. Further, when the developer passes through the opposing portion of the magnetic pole N1, it is released from the restraining force of the magnetic pole at the opposing portion of the non-magnetic pole area M, and flies in the form of a lump in the transport direction. This flying developer collides with the leveling member 37 and is leveled to a constant layer thickness (corresponding to the gap DB2), is held by the thin film member 34 and conveyed in the direction of arrow C, and is moved between the thin film member 34 and the photoreceptor 100. is sent into contact area X with

The developer conveyed through the contact area X moves from the direction of arrow i due to the contact pressure of the thin film member
If an electrostatic latent image is formed on the surface of the photoreceptor 100, the electrostatic latent image is pressed against the surface of the photoreceptor 100, and the potential difference between the surface potential of the electrostatic latent image and the developing bias voltage VB transmitted from the cylindrical body 31 to the thin film member 34 is applied. As a result, toner electrostatically adheres to the electrostatic latent image area.

When there is a relative speed difference between the thin film member 34 and the photoconductor 100, the developer transported through the contact area Then, it undergoes a pancreatic effect. Therefore, the carrier that has lost toner due to development is mixed with the carrier that still retains toner, and the carrier that has lost toner does not come into continuous contact with the photoreceptor. Therefore, the toner attached to the electrostatic latent image on the photoconductor 100 is not taken away by the carrier that has lost the toner, and the toner is attached to the electrostatic latent image at an approximately -like density, resulting in a flat and soft image. (An image in which only the edges are not emphasized) is obtained.

The developer which has passed through the contact region
It is transported in the direction of arrow C. Then, in the non-magnetic pole region M between the magnetic poles N3 and N4, it is released from the restraining force of the magnetic poles and falls into the supply chamber 11.

The developer regulated by the regulating member 36 and collected in the collecting section 40 is conveyed backward through the empty chamber 46 based on the rotation of the feeding blades 47 and 48, and is supplied to the supply chamber 11 through the falling path 45.

If it is determined based on the output of the toner concentration detection sensor 28 that the toner concentration of the developer is lower than a predetermined reference value, the blades 52 . 53 each rotate,
The toner in the storage chamber 51 is sent to the supply chamber 54. Supply room 5
The toner supplied to No. 4 is held by a brush roll 55 and conveyed in the direction of the arrow.

The brush roll 55 is sequentially deflected by engagement with the flicker rod 57, causing the toner held between the brushes to fall onto the mesh 56. Further, when the brush is disengaged from the flicker rod 57, it returns to a straight state due to its own elasticity, and at this time, the bristles hit the mesh 56, and the toner on the mesh falls and is supplied to the empty space 46 below. do.

Furthermore, due to the vibration when the brush returns to its original position and the impact when hitting the mesh 56, toner adhering to the brush itself falls onto the mesh. Therefore, even if the brush and toner are each charged with an electric charge due to their contact with the casing, and the toner adheres to the brush due to their electrical attraction, the toner is easily peeled off from the brush due to the impact or the like. Therefore, the toner conveying performance of the brush roll 55 is maintained satisfactorily.

The toner that has passed through the mesh 56 falls in a dispersed state and is quickly mixed with the developer in the empty chamber 46, and is quickly charged by being mixed with the developer. Therefore, uncharged toner is not subjected to development, and the generation of toner powder smoke and fog on images are reduced.

Toner powder smoke is generated in the empty chamber 46 due to the mixing of the developer, and either a part of it adheres to the mesh 56, or this adhered toner is removed by a mesh cleaning device 60. That is, as shown in FIGS. 4 to 6, the cam 64 rotates with the rotation of the stirring blade 53, and its tip presses the mesh 56 in the direction of arrow J, and the lower surface of the mesh comes into contact with the brush 62, and the cam 64 is attached thereto. removed toner. Further, when the cam 64 and the mesh 56 are disengaged, the mesh 56
is restored to the state shown in FIGS. 5 to 4 by the biasing force of the plate spring 63.

Therefore, the aperture ratio of the mesh 56 is maintained constant,
Stable supply of toner becomes possible.

Note that the device for cleaning the lower surface of the mesh is not limited to the above-mentioned embodiment, and may be, for example, as shown in FIG. The means for operating the mesh or cleaning member may be a cam 64.
It may be something other than that.

The mesh cleaning device shown in FIG. 7 may be basically the same as that shown in FIGS. Since the entire lower surface of the mesh 56 is cleaned,
Toner attached to 6 will not fall in clumps,
There is an advantage.

In the cleaning device shown in FIGS. 8 and 9, springs 67 and 67 urge the rear and front sides of a support base 65 that supports a brush 66 to the left in the figure, and the rotation of a cam 64 causes the springs to
7, the brush 66 is moved left and right to clean the lower surface of the mesh.

By the way, the output of the toner concentration detection sensor 28 varies depending on the amount of developer passing through the opposing portion (see FIG. 13), and if the output of the toner concentration detection sensor 28 varies, the toner concentration of the developer measured also changes. (See Figure 12). Therefore, when measuring the toner concentration of the developer, it is important to stabilize the amount of the developer located at the portion facing the toner concentration detection sensor 28 in order to accurately measure the toner concentration. In particular, when images are formed continuously in an image forming apparatus such as a copying machine, the fluidity of the developer decreases as the internal temperature rises and the stress on the developer increases, causing the sensor surface of the toner concentration detection sensor to drop. There is a problem in that the amount of developer passing above decreases, making it impossible to obtain an accurate toner concentration and making it impossible to properly manage the toner concentration.

For this reason, as shown in FIG.
It is desirable to provide a regulating member 126 in the center of the control member 126.

Here, the regulating member 126 has truncated conical inclined portions 1 on both sides of a base portion 127 having a circular cross section and a larger diameter than the shaft 123.
28, 128, a flexible scooping plate 124 is provided on the outer periphery of the base 127, and the M portion 127 is opposed to the sensor surface of the toner concentration detection sensor 28.

Therefore, the developer in the concentration detection section 20 is
25 and 125 toward the center, along the slope 128 to the area of the base 127, scooped by the scooping plate 124, and sent back to the supply section 10.

Since the base 127 has a larger diameter than the shaft 123, even if the amount of developer in the concentration detection section 20 is small, the base 127
7 and the toner concentration detection sensor 127, the output of the toner concentration detection sensor 28 becomes stable, and accurate concentration detection becomes possible.

Further, since the slope portions 128.1-28 are provided on both sides of the base portion 127, the developer sent by the blades 125 is smoothly conveyed to the opposing area of the base portion 127 along the slope portions 128,128.

Therefore, as shown in FIG. 11, if the regulating member 126 does not have an inclined portion, the developer may accumulate at the step between the shaft 123 and the regulating member 126, reducing the conveyance of the developer. In contrast, the conveying blades 22 shown in FIG. 10 do not cause such inconvenience, and the developer is smoothly moved.

In the above description, the present invention is applied to a developing device that uses a two-component developer consisting of toner and carrier, but it can also be applied to a developing device that uses only toner.

〔Effect of the invention〕

As is clear from the above description, the developer replenishing device of the present invention rotates while sliding the mesh, the powder developer accommodated on the mesh, and the upper surface of the mesh, and supplies the developer below the mesh. The mesh includes rotating means for dropping and cleaning means for removing toner adhering to the lower surface of the mesh, and the cleaning means removes toner adhering to the lower surface of the mesh.

Therefore, cross-linking of toner on the lower surface of the mesh is prevented, the mesh opening ratio is maintained at a constant value, and stable toner replenishment is possible.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the developing device, Figure 2 is a diagram showing the flow of developer in the supply section and concentration measuring section, Figure 3 is a partially enlarged cross-sectional view of the developing device, and Figures 4 and 5 are mesh cleaning. A side view of the device, FIG. 6 is a partially cutaway perspective view of the mesh cleaning device, and FIG. 7 is a side view of the device.
, 8 is a side view showing another embodiment of the mesh cleaning device,
FIG. 9 is a perspective view of the mesh cleaning device shown in FIG.
Figure 0 is a front view of another embodiment of the conveyance blade, Figure 11 is a front view of the conveyance blade shown for comparison, Figure 12 is a diagram showing the relationship between the output of the toner concentration detection sensor and the toner concentration, and Figure 13. 2 is a diagram showing the relationship between the toner concentration detection sensor output and the amount of developer. FIG. ■...Developing device, 50...Toner supply section, 54...Supplementary fQL55 - Brush roll, 56 - Mesh, 6
0...Mesh cleaning device, 62...Bluff, 63...
Board blade, 64 cam. Patent Applicant Minolta Camera Co., Ltd. Agent Patent Attorney Seihaku Ao and 1 other person■ Also -ii θ Figure 7 Figure 8 Negative 'S12 Figure Y ner trace (wt%) Negative '513 Figure Moonshii, Yes1) Quantity

Claims (1)

[Claims] (1) A mesh, a powder developer accommodated on the mesh, a rotation means that rotates while slidingly contacting the upper surface of the mesh and drops the developer below the mesh, and a developer attached to the lower surface of the mesh. A developer replenishing device comprising: cleaning means for removing.