JP2961809B2 - Developer supply device - Google Patents

Description

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

[Conventional technology]

Conventionally, as the developer supply device, Japanese Patent Publication No.
And US Pat. No. 4,595,277.

The former (Japanese Patent Publication No. 40-13231) includes a developer tank provided with a developer accommodating section and a developer replenishing section, and a developer tank disposed in the developer replenishing section and in contact with the developer supplied from the developer accommodating section. And a slit provided on an appropriate peripheral surface of a developer tank that covers the rotating brush.

In this developer replenishing device, the developer held by the rotating brush is conveyed to the slit-facing portion, and the developer held between the brushes is dropped and replenished below the slit through the slit by contact between the rotating brush and the slit. You.

In the latter (U.S. Pat. No. 4,595,277), the bottom of the toner hopper is covered with an upwardly curved screen having a plurality of holes, and an agitator provided with a plurality of rods around the inside of the toner hopper is rotated by the rods. It is provided so as to slide on the upper surface.

In this developer replenishing device, the screen moves up and down due to the rotation of the agitator, and toner is dropped and supplied through holes in the screen.

[Problems to be solved by the invention]

However, in the developer replenishing apparatus described in Japanese Patent Publication No. 40-13231, the charged developer and the rotating brush are electrically attracted by contact with the casing, and the developer is interposed between the brushes. May be clogged.

In this case, since the developer once adhered to the brush is stably held between the brushes, there has been a problem that the developer replenishing ability of the rotating brush is significantly reduced, and the necessary developer cannot be supplied.

In addition, the clogging of the slit eyes due to the toner due to long-time use causes the same problem.

As another problem, the developer replenishing apparatus described in Japanese Patent Publication No. 40-13231 and U.S. Pat. No. 4,595,277 does not include a developer tank that forms a slit or a means for cleaning the lower surface of a screen.

Therefore, the developer powder generated in a portion (for example, a developer mixing and stirring unit) where the developer is supplied via the slit or the screen of the developer tank adheres to the lower surface of the developer tank and the screen, and a crosslinking phenomenon occurs. There has been a problem that the effective cross section of the slit and the screen hole is reduced, and the ability to supply the developer is reduced.

Certainly, in the case where the rod slides on the screen as in the latter, a slight amount of adhered toner drops due to the vibration of the screen, but cannot be completely removed.

[Means for solving the problem]

As a specific means for solving the above-mentioned problems, the present invention described in claim 1 rotates a mesh, a powder developer contained on the mesh, and the mesh upper surface while slidingly contacting each other. A rotating brush for dropping the developer below the mesh, wherein a flicker member is provided upstream of the mesh in the rotating direction of the rotating brush, and the flicker member is repelled by the rotating brush based on the rotation of the rotating brush. The brush material is configured to hit the mesh surface.

Similarly, in the developer supply device according to the present invention, in the developer supply device, the mesh, the powder developer contained on the mesh, and the top surface of the mesh are rotated while being in sliding contact with each other, and the developer is provided below the mesh. And a cleaning unit disposed opposite to the lower surface of the mesh and for removing the developer adhered to the lower surface of the mesh.

[Action]

According to the developer replenishing device according to the present invention, when the rotating brush rotates, the brush constituting the rotating brush repeatedly engages with the flicker member, and the developer attached to the brush and the space between the brushes. The retained developer falls.

In addition, the surface of the mesh is hit by the repelling force when the tip of the brush material leaves the flicker member, and the developer clogged in the mesh is also dropped.

Therefore, the replenishing performance of the rotating brush and the mesh is restored every time the rotating brush contacts the flicker member, and the original replenishing performance can be maintained.

According to the developer replenishing apparatus according to the present invention, the developer is dropped and replenished below the mesh via the mesh by the rotation of the rotating means.

Further, the developer adhered to the lower surface of the mesh is removed by the cleaning means arranged opposite to the lower surface of the mesh.

The developer powder soared from the dropped and supplied developer and adhered to the lower surface of the mesh is removed by the cleaning unit.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

A. Configuration of Developing Device The developing device 1 shown in FIG. 1 generally includes a supply unit 10, a density detecting unit 20, a developing unit 30, a collecting unit 40, and a toner replenishing unit 50.

i. Supply Unit 10 The supply chamber 11 of the supply unit 10 is provided with a supply blade 12. The supply blades 12 are provided with side plates 14, 1 provided at both ends of the shaft 13, respectively.
A plurality of scooping plates 15 are laid horizontally on the outer periphery of 4, and arrow a
It can be driven to rotate in the direction.

ii. Density Detection Unit 20 The concentration detection unit 20 is provided at the rear (left side in the figure) of the supply unit 10, and is connected to the transport path 21 which is continuous with and parallel to the supply chamber 11.
Is provided with a transfer blade 22. As shown in FIG. 2, the transport blade 22 has a scooping plate 24 at the center of a shaft 23, and a plurality of blades 25 on both sides thereof at predetermined intervals. These feathers 25
The mounting angle is different between the left and right sides of the scooping plate 24, and the transportability due to the rotation of the transport blades is different between the left and right sides.
In other words, in FIG. 2, the left blade 25 has a transport property to the right, and the right blade 25 has a transport property to the left.
Also. An opening 27 is provided in a portion of the wall 26 between the supply chamber 11 and the transport path 21 where the scooping plate 24 faces. Further, a toner concentration detection sensor 28 for measuring a change in the magnetic permeability of the developer is provided at a central bottom portion of the transport path 21, and its sensor surface is made substantially coincident with the bottom surface of the transport path 21.

iii.Developing unit 30 In the developing unit 30, the cylindrical body 31 is made of a non-magnetic material, and is opposed to the photoconductor 100 with a predetermined gap.
It is driven to rotate in the direction of arrow c about an axis (not shown). Further, the cylindrical body 31 is connected to a power supply 32, a predetermined bias voltage V _B is adapted to be applied.

The magnet body 33 has a plurality of magnetic poles (N ₁ , N ₂ , S ₁ , N ₃ , N ₄ , S ₂ , N ₅ , S ₃ ) extending in the axial direction of the cylindrical body 31 on the outer periphery in this order. The magnetic poles N ₁ and N ₂ and the magnetic poles N ₃ and N ₄ of the same polarity are adjacent to each other, and the middle between them is a non-magnetic pole region M ₁ , M ₂ respectively. Fixed, said non-magnetic pole region
The M ₁ located above the facing portion of the cylindrical body 31 and the photosensitive member 100, no magnetic pole region M ₂ is are then positioned in opposing portions of the supply blades 12.

The thin-film member 34 is a thin-walled (thickness 0.2 mm) cylindrical body having a circumference slightly longer than the circumference of the cylindrical body 31, and is provided on the cylindrical body 31. The thin film member 34 is made of nylon, polyimide, or polycarbonate, and has conductivity by adding carbon.

The regulating member 36 is attached to the upper part of the developing tank, and the tip thereof is opposed to the upper outer peripheral surface of the cylindrical body 31 with a predetermined gap _DB1 .

Leveling member 37 is attached to the developing tank through the regulating member 36, it is allowed to face each other with a predetermined gap D _B2 in the vicinity of the region where the tip is opposed to the free pole area M ₁ of the thin film member 34.

iv. Collection unit 40 The collection unit 40 is located above the supply unit 10 and the supply unit
10, a front wall 42 of the partition wall 41 is formed at a predetermined interval from the cylindrical body 31, a passage 43 is provided between the upper end thereof and the regulating member 36, and the rear wall 44 of the partition wall 41 has a concentration Measuring unit 20
A drop path 45 communicating with the supply chamber 11 is provided between the supply path 11 and the upper cover 29. Further, the collection unit 40 is provided with two feed blades 47 and 48 at the front and rear, and is configured to be driven to rotate in the directions of arrows d and e, respectively.

v. Toner Replenishing Unit 50 In the toner replenishing unit 50, a storage chamber 51 and a replenishing chamber 54 are formed, and an opening is provided at the bottom of the replenishing chamber 54 so that the opening is located above the empty chamber 46. is there. The stirring blades 52 and 53 are disposed in the storage chamber 51, respectively, and are driven to rotate in the directions of arrows f and g. The brush roll 55 has a brush provided around the shaft, is arranged in the supply chamber 54, and is driven to rotate in the direction of arrow h. The housing of the supply chamber 54 facing the lower part of the brush roll 55 has a curved surface so that the tip of the brush is lightly in contact.

The mesh 56 is composed of a net-like body formed by knitting wires in a grid or a plate-like body having a large number of holes formed in a thin plate, and is arranged so as to close the bottom opening of the supply chamber 54.
The upper surface of 56 is slid lightly. Flicker stick 57
Is the area where the brush moves, and the brush roll is located upstream of the mesh 56 with respect to the moving direction of the brush roll 55.
It is provided in parallel with 55.

The mesh 56 can be moved in the left-right direction in the figure, and the mesh cleaning device 60 cleans the lower surface of the mesh according to the movement.

As shown in FIGS. 4 to 6, the mesh cleaning device 60 includes a support table 61 provided in a region below the mesh 56 and just below the bottom opening of the supply chamber 54, and A brush 62 that has been planted and has a bristle tip capable of contacting the lower surface of the mesh, a leaf spring 63 that urges the mesh 56 to the left at the right end in the figure, and fixed to both ends of a shaft 53a of a stirring blade 53, And cams 64 for intermittently pressing the left end in the figure.

B. Development Operation The development operation will be described.

As the developer, a two-component developer composed of a toner and a magnetic carrier is used. The developer is also magnetically attracted to the outer peripheral portion of the thin film member 34, and the excess portion of the thin film member 34,
The longer portion than the peripheral length of 31 is concentrated to the portion facing the non-pole area M ₁ to form a 35 bulge, the outer peripheral portion of the bulge 35 is the photoconductor
It is in contact with the outer circumference of 100. The contact width α of the bulge 35 is wider than the width of the contact between the developer and the photosensitive member in the magnetic brush type developing device, and is set to, for example, about 6 to 12 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 the carrier are brought into frictional contact to be charged to opposite polarities. A part of the developer is transported by the scooping plate 15 to the concentration measuring unit 20 over the wall 26, and the developer scooped by the scooping plate 15 is supplied 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 15 is regulated by a regulating member 49 composed of a brush provided below the partition 41, and the supply amount is adjusted to be constant. Therefore, even if the developer with a relatively high toner concentration supplied from the falling path 45 falls on the developer on the scooping plate 15, the high-concentration developer is scraped off by the regulating member 49 and directly enters the supply area P. It will not be sent.

The developer sent to the density measuring unit 20 is conveyed toward the center by the blades 25 by the rotation of the conveying blades 22, and is joined and mixed at the center, and is scooped by the scooping plate 24 to be supplied to the supply chamber 11 by the scooping plate 24.
Sent back to. The developer sent back to the supply chamber 11 is dispersed right and left by the mixing and stirring action of the supply blade 12. As shown in FIG. 2, when two blades 16 and 16 are provided at the center of the supply blade 12 and the respective angles with respect to the shaft 13 are set to be opposite, the developer sent back from the transport path 21 is positively affected. A part of the developer returned from the left side of the transport path 21 is supplied to the right side of the supply chamber 11 and a part of the developing unit returned from the right side of the transport path 21 is supplied to the right and left sides. The left and right developers are mixed by being transported to the left side of the chamber 11,
There is no inconvenience that the toner concentration (the weight mixing ratio of the toner to the carrier) of only the left or right developer decreases.

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

On the other hand, the developer held on the outer peripheral portion of the thin film member 34 in the supply area P is held based on the magnetic attractive force of the magnet 33,
It is conveyed in the direction of the arrow c by the rotation of the cylindrical body 31, and the regulating member
Regulated to 36.

The developer regulated by the regulating member 36 is collected by the collection unit 40 through the passage 43. Therefore, there is no possibility that the developer stays forever and receives stress before the regulating member 36.
The deterioration of the developer is reduced.

As shown in FIG. 3, the developer that has passed through the tip of the regulating member 36 is conveyed in a magnetic brush state at a portion facing the magnetic poles N ₅ , S ₃ , and N ₁ . The developing agent passes through the opposing portions of the magnetic poles N _1, continue to fly a lump in the conveying direction is released from restraint of the magnetic pole at the opposite end of the non-magnetic pole area M _1. The flying developer collides with the leveling member 37 and has a certain layer thickness (gap D).
_B2 ), and is transported in the direction of arrow c while being held by the thin film member 34, and is brought into contact area X between the thin film member 34 and the photoconductor 100.
Sent to.

The developer conveyed in the contact area X is pressed against the surface of the photoconductor 100 moving in the direction of arrow i by the contact pressure of the thin film member 34, and an electrostatic latent image is formed on the surface of the photoconductor 100. lever, based on the potential difference between the developing bias voltage V _B transmitted from the surface potential and the cylindrical body 31 of the electrostatic latent image on the thin film member 34, the toner is electrostatically adhered to the electrostatic latent image portion.

When there is a relative speed difference between the thin film member 34 and the photoconductor 100, the developer conveyed in these contact areas X is in a state where the magnetic binding force by the magnet body 33 provided in the cylindrical body 31 is weak. And undergoes a shearing action. Therefore, the carrier that has lost the toner due to the development and the carrier that still retains the toner are mixed, and the carrier that has lost the toner does not continuously contact the photoconductor. Therefore, the photoconductor 10
The toner attached to the 0 electrostatic latent image is not robbed by the carrier that has lost the toner, and the toner adheres to the electrostatic latent image at a substantially uniform density, and a flat image (only edges are emphasized) Not image) is obtained.

Developer that has passed through the contact area X is subjected to a magnetic restraint force of the magnetic pole N _2, held by the thin film member 34 in a magnetic brush state again, and is conveyed in the direction of arrow c. Then, it is released from the restraining force of the magnetic pole without pole region M ₂ between the magnetic poles N ₃ and N ₄ drops into the supply chamber 11.

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

When it is determined from 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 and 53 of the toner
Is fed into the supply chamber 54. The toner supplied to the replenishing chamber 54 is held by the brush roll 55 and transported in the direction of arrow h.

The brush roll 55 is sequentially bent and bent by the engagement with the flicker bar 57, and the toner held between the brushes falls onto the mesh 56. When the brush comes out of engagement with the flicker bar 57, the brush returns to a linear state due to its own elasticity. At this time, the bristle tip hits the mesh 56, and the toner on the mesh falls and is supplied to the empty chamber 46 therebelow. I do. Further, the toner adhering to the brush itself falls on the mesh due to the vibration at the time of returning or the impact at the time of hitting the mesh 56. Therefore, even if the brush and the toner are charged by the contact with the casing, and the toner adheres to the brush by their electric attraction force, the toner is easily separated from the brush by the impact or the like.
Therefore, the toner transportability of the brush roll 55 is maintained satisfactorily.

The toner that has passed through the mesh 56 falls in a dispersed state, is quickly mixed into the developer in the empty space 46, and is quickly charged by mixing with the developer. Therefore, the uncharged toner is not subjected to the development, and generation of toner dust, fog on the image, and the like are reduced.

In the empty room 46, toner dust is generated due to the mixing of the developer, and a part of the dust adheres to the mesh 56. The attached toner is removed by the mesh cleaning device 60. That is, as shown in FIGS. 4 to 6, the cam 64 rotates together with the rotation of the stirring blade 53, and the tip of the cam 64 presses the mesh 56 in the direction of arrow j. The removed toner is removed. Also cam 64 and mesh
When the engagement with the mesh 56 is released, the mesh 56 returns to the state shown in FIGS. 5 to 4 by the urging force of the leaf spring 63.

Therefore, the aperture ratio of the mesh 56 is kept constant,
Stable replenishment of toner becomes possible.

The apparatus for cleaning the lower surface of the mesh is not limited to the above-described embodiment. For example, the apparatus for cleaning the lower surface of the mesh may be as shown in FIGS. The means for operating the mesh or the cleaning member may be other than the cam 64.

The mesh cleaning device shown in FIG. 7 has brushes 62 arranged on the right and left sides of the mesh 56 in the drawing.
5 is the same as that shown in FIG. 5, but according to the present embodiment, since the entire lower surface of the mesh 56 is cleaned, there is an advantage that the toner attached to the mesh 56 does not drop as a lump.

The cleaning device shown in FIGS. 8 and 9 urges the back side and the front side of the support base 65 supporting the brush 66 to the left side in the figure by springs 67 and 67, and against the spring 67 by the rotation of the cam 64. 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 opposite portion (see FIG. 13), and when the output of the toner concentration detection sensor 28 varies, the toner concentration of the developer is measured. Also changes (see Figure 12). Therefore, in measuring the toner concentration of the developer, it is important to stabilize the amount of the developer located at the opposite portion of the toner concentration detection sensor 28 in measuring the accurate toner concentration. In particular, when an image is continuously formed by an image forming apparatus such as a copier, the fluidity of the developer decreases with an increase in the temperature inside the machine or an increase in stress applied to the developer, and the sensor surface of the toner density detection sensor is changed. There is a disadvantage that the amount of developer passing therethrough is reduced, so that an accurate toner density cannot be obtained, and that proper toner density management cannot be performed.

For this reason, as shown in FIG. 10, it is desirable to provide a regulating member 126 at the center of the transport blade 22.

Here, the regulating member 126 has truncated cone-shaped inclined portions 128 and 128 on both sides of the base 127 having a circular cross section larger than the shaft 123, and includes a flexible scooping plate 124 on the outer periphery of the base 127. The base 127 is opposed to the sensor surface of the toner concentration detection sensor 28.

Therefore, the developer of the density detecting section 20 is
5,125, respectively, is conveyed toward the central portion, is conveyed along the inclined portion 128 to the region of the base 127, and the scooping plate 124
And sent back to the supply unit 10.

And since the base 127 has a larger diameter than the shaft 123,
Even if the amount of developer in the density detecting section 20 is small, a certain amount of developer passes between the base 127 and the toner density detecting sensor 127, so that the output of the toner density detecting sensor 28 is stabilized and accurate density detection is performed. Becomes possible.

Further, since the inclined portions 128, 128 are provided on both sides of the base portion 127, the developer sent by the blade 125 is smoothly transported along the inclined portions 128, 128 to the region opposed to the base portion 127.

Therefore, as shown in FIG. 11, when the regulating member 126 does not have an inclined portion, the developer stays at the step between the shaft 123 and the regulating member 126, so that its transportability is reduced, While unnecessary stress is applied, the transfer blade 22 shown in FIG.
In this case, there is no such inconvenience, and the developer is smoothly moved.

In the above description, the case where the present invention is applied to a developing device using a two-component developer including a toner and a carrier has been described, but the present invention can also be applied to a developing device using only a toner.

〔The invention's effect〕

As is apparent from the above description, in the developer supply device according to the first aspect of the present invention, when the brush of the rotating brush is engaged with the flicker member, the developer held between these brushes is removed. Fall. Further, due to the vibration when the engagement with the flicker member is released, the developer electrostatically attracted to the brush also drops. Further, the brush flipped by the flicker member strikes the mesh, and the developer adhering to the mesh and the developer clogged with the mesh are forcibly dropped.

Therefore, the developer replenishment of the rotating brush and the mesh is properly maintained, and a sufficient amount of developer can be supplied to the development.

Similarly, in the developer supply device according to the present invention described in claim 2, the mesh, the powder developer contained on the mesh, and rotating while slidingly contacting the upper surface of the mesh,
A rotating unit for dropping the developer below the mesh; and a cleaning unit disposed opposite to the lower surface of the mesh to remove the developer adhered to the lower surface of the mesh. Try to remove toner.

Therefore, the cross-linking of the toner on the lower surface of the mesh is prevented, the mesh opening ratio is maintained at a constant value, and the toner can be supplied stably.

[Brief description of the drawings]

FIG. 1 is a sectional view of the developing device, FIG. 2 is a diagram showing the flow of the developer in a supply section and a concentration measuring section, FIG. 3 is a partially enlarged sectional view of the developing apparatus, and FIGS. FIG. 6 is a side view of the device, FIG.
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. 8, FIG. 10 is a front view of another embodiment of the conveying blade, and FIG. FIG. 12 is a diagram showing the relationship between the toner density detection sensor output and the toner density, and FIG. 13 is a diagram showing the relationship between the toner density detection sensor output and the developer amount for comparison. is there. 1 ... developing device, 50 ... toner supply section, 54 ... supply chamber,
55 ... brush roll, 56 ... mesh, 60 ... mesh cleaning device, 62 ... brush, 63 ... leaf spring, 64 ... cam.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tamotsu Shimizu 2-3-13-1 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Kokusai Building Minolta Camera Co., Ltd. (72) Inventor Masahiko Matsuura Azuchi, Chuo-ku, Osaka-shi, Osaka 2-3-3, Osaka-cho, Osaka International Building Minolta Camera Co., Ltd. (56) References JP-A-60-249173 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G03G 15 / 08

Claims (2)

(57) [Claims] 1. A mesh and a powder developer accommodated on the mesh are rotated while slidingly contacting the upper surface of the mesh,
A rotary brush for dropping the developer below the mesh, wherein a flicker member is provided upstream of the mesh in the direction of rotation of the rotary brush, and the flicker member is repelled by the flicker member based on the rotation of the rotary brush. A developer replenishing device, wherein a brush material hits the mesh surface. 2. A mesh, a powder developer contained on the mesh, rotating means for rotating the mesh upper surface while slidingly contacting the mesh upper surface, and dropping the developer below the mesh, and opposing the lower surface of the mesh. And a cleaning means for removing the developer attached to the lower surface of the mesh.