JPH06167875A - Developer circulating/stirring device - Google Patents

Abstract

PURPOSE:To moderately mix the developers of the left and right regions in a developer circulating/stirring device, to improve the dispersibility of toner and to stabilize an image density by providing a moving device for moving back and forth a first stirring/ carrying member along a first developer carrying path. CONSTITUTION:A developer circulating/stirring part is composed of a main stirring part 11 and a substirring part 21 at a one-step higher up position on the rear of the main stirring part 11. When the rotation of a driving motor not shown in the Figure is transmitted to a driving gear 39, a backet roller 12 is rotated via the gears 39 and 17 and simultaneously, the rotation is transmitted to the first stirring/carrying member 24 via the gears 17, 86 and 81 to rotate the member 24. Further, the rotation of the gear 86 is transmitted to a cam 82 via bevel gears 87 and 88 and the first stirring/carrying member 24 is periodically moved in an axial direction. Therefore, an extruding member 26 is horizontally moved in the axial direction and a position where the developer is supplied from the substirring part 21 to the main stirring part 11 is changed. Thus, the developers in the left and right regions of the main scanning part 11 and the subscanning part 21 are moderately mixed and the dispersibility of the toner can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer circulating stirring device for mixing and stirring powder developer in a developing device such as a copying machine or a printer while stirring and circulating.

[0002]

2. Description of the Related Art Conventionally, as the developer circulating agitator,
Inside the developing tank, there are provided a first screw for moving the developer from both end sides to the central part, and a second screw arranged in parallel with the first screw for moving the developer from the central part to the both end sides, The one in which the developer is circulated and conveyed in a figure eight shape by the first screw and the second screw is proposed in Japanese Utility Model Publication No. 50-27333.

[0003]

However, in the developer circulation agitator, the developers conveyed from the left and right ends by the first screw merge at the central portion, and the second screw makes a boundary at the merge position. It is sent back to both ends. That is, the developer conveyed from the left side area by the first screw is sent back to the original left side area by the second screw, and the developer conveyed from the right side by the first screw is the original right side area by the second screw. Sent back to. Therefore, this developer circulation agitator has the advantages that the developer circulation cycle is short and the replenished toner diffuses uniformly early. However, the developer in the left and right areas is circulated only in each area, the developers in both areas do not actively mix, and only the toner concentration of the developer in one area may decrease or increase. Had a point. Therefore, the present invention is made in order to improve the dispersibility of the toner and stabilize the image density by appropriately mixing the developers in the left and right regions in the developer circulating and stirring device.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems and includes a first developer carrying path, a second developer carrying path adjacent to the first developer carrying path, and a second developer carrying path. A first stirring / transporting member provided on the first developer transporting path;
In the first developer transport path, the developer is transported from both end sides to the central portion based on the second stirring transport member provided in the developer transport path and the driving of these stirring transport members. In the developer circulating agitator, which is sent to the second developer carrying path, and in the second developer carrying path, the developer is carried from the central portion to both ends while being sent back to the first developer carrying path, A moving device for reciprocating the first agitating / conveying member along the first developer conveying path is provided.

[0005]

In the developer circulating / stirring device, the first stirring / transporting member reciprocates along the first developer transporting path. Corresponding to this reciprocal movement, the position at which the developer is sent from the first developer stirring / transporting path to the second developer stirring / transporting path moves. As a result, the developer conveyed from the right side (left side) area of the first developer agitation path is positively fed also to the left side (right side) area of the second developer agitation path, and the left and right areas are The developer mixes reasonably well.

[0006]

EXAMPLES A specific example of the developer circulating and stirring device having the above-mentioned configuration will be described.
A developing device equipped with this will be described together. I. Configuration of Developing Device FIG. 1 shows the overall configuration of the developing device. The developing device is roughly composed of a developer circulation stirring unit 1, a developing unit 3, a recycling conveying unit 4, a toner replenishing unit 5, and a toner collecting unit 7. ing.

I. Developer Circulation Stirring Unit 1 The developer circulation stirring unit 1 is composed of a main stirring unit 11 and a sub stirring unit 21 provided at a higher position behind the main stirring unit 11. Main Stirring Section 11 The main stirring section 11 is provided with a bucket roller 12. The bucket roller 12 has side plates 14 and 14 on both ends of the shaft 13.
(One of them is not shown) is attached to these side plates 1
Buckets 15 are laterally provided on the outer circumference of 4, 14 at predetermined intervals. Further, as shown in FIG. 3, gears 17, 17 are fixed to both ends of the shaft 13, respectively, and one gear 17 is engaged with a drive gear 39. Further, among the plurality of buckets 15, a pair of opposing buckets 15a,
A plurality of feed blades 16 are attached to the inner surface of 15b at predetermined intervals, and as shown in FIG. 2, the feed blade 16a in the left side area and the feed blade 16b in the right side area are bordered by the center line CL.
By setting the mounting angles for the buckets 15a and 15b to be opposite and rotating the bucket roller 12 in the direction of arrow a, the feed blade 16a in the left side region is leftward (arrow m ′).
Direction), and the feed blade 16b in the right side area has a rightward direction (arrow n'direction). A plurality of partition walls 19 are symmetrically provided between the sub stirring unit 21 and the main stirring unit 11 at predetermined intervals, and the main stirring unit 1 is provided via a plurality of passages 20 formed between them.
1 and the sub-stirring part 21 are connected.

Sub-stirring part 21 The sub-stirring part 21 is provided with a stirring / transporting member 24. A cylindrical regulating member 27 having a pushing member 26 in the center is concentrically attached to the shaft 25 of the stirring and conveying member 24, and a screw 28 is provided on both sides of the regulating member 27.
a and 28b are attached. The screw 28a,
The blades 29a, 29b of 28b are attached in the opposite direction, and by rotating the stirring and conveying member 24 in the direction of arrow b,
The screw 28a in the left side region has a property of conveying to the right side (direction of arrow m), and the screw 28b in the right side region has a property of conveying to the left side (direction of arrow n). The stirring and conveying member 24
3 is rotatably and axially movably supported on the side wall of the developing tank 10 as shown in FIG.
It is designed to periodically reciprocate.

Moving Device 80 In the moving device 80, the gear 81 is fixed to one end of the shaft 25. The cam 82 is arranged in a direction orthogonal to the shaft 25 and fixed to a shaft 83 fixed to the developing tank 10 or the main body (not shown) of the image forming apparatus, and is provided between the gear 81 and the developing tank 10. The end face of the shaft 25 or the side face of the gear 81 is pressed against the outer peripheral face of the cam 82 by the urging force of the spring 84. The cam 82 has an eccentric cam,
It is preferred to use an elliptical cam. The shaft 85 is the developing tank 10.
Is rotatably attached to the side wall of the shaft 25 in parallel with the shaft 25, and a gear 86 provided on the shaft 85 is meshed with the gear 81 and the gear 17 of the bucket roller 12.
Bevel gear 87 fixed coaxially with the end of the shaft 8
It is meshed with the bevel gear 88 provided on the No. 3.

Ii. Developing Unit 3 The developing unit 3 includes a developing roller 31 facing the photoconductor 100.
Is provided. The developing roller 31 is a fixed magnet body 32.
And a sleeve 33 which is externally mounted on the fixed magnet body 32. As shown in FIG. 3, a gear 37 provided on a shaft 36 of the sleeve 33 is meshed with a drive gear 39. The outer periphery of the magnet body 32, a plurality of magnetic poles _N 1 which extends in the axial _{direction, N 2, S 1, N} 3, N 4, S 2, N 5, S 3 is in this order in the direction of the arrow c Between the magnetic poles N ₁ and N ₂ that are arranged and have magnetic poles of the same polarity arranged side by side, the non-magnetic pole portion M ₁ and the magnetic pole N similarly.
₃ and N ₄ form a non-magnetic pole portion M ₂ and the non-magnetic pole portion M ₁
Is located above the closest position P between the sleeve 33 and the photoconductor 100, and the non-magnetic pole portion M ₂ is located at the portion facing the bucket roller 12. The first limiting plate 34 and the second regulating plate 35 are both positioned above the sleeve 33, the distal end of the first limiting plate 34 is Yes to face the sleeve outer peripheral surface at the opposite end of the magnetic pole N _5, the second regulating plate 35 Is opposed to the outer peripheral surface of the sleeve at a position where the tip of the sleeve slightly moves in the direction from the magnetic pole N ₁ to the magnetic pole N ₂ .

Iii. Recycle Transport Unit 4 In the recycle transport unit 4, the structure 41 is disposed above the developer circulation stirring unit 1, and the first transport unit 43 is located in the front part and the rear part is located in the upper part of the structure body 41 with the wall 42 interposed therebetween. The second transport unit 44 is formed, and the first transport unit 43 includes the first transport member 47,
A second transport member 48 is provided in the second transport section 44. Further, between the front end portion (the right end portion in FIG. 1) of the structure 41 and the first regulation plate 34, an entrance 45 communicating with the first transport portion 43 is formed, and the second portion is provided at the rear portion of the structure 41. A drop path 46 that connects the transport unit 44 and the main stirring unit 11 is formed. Further, on the lower surface of the structure 41, a scraping member 49 protruding to the main stirring section 11 is provided.

Iv. Toner Replenishing Section 5 The toner replenishing section 5 is generally composed of a housing section 51 and a drop replenishing section 61.
It is composed of. Housing 51 The housing 51 is provided with stirring blades 52 and 53. Between the accommodation portion 51 and the drop supply portion 61, the accommodation portion bottom plate 54
And an opening 56 provided between the walls 55 located above the
Have been contacted via. Drop Replenishing Section 61 The drop replenishing section 61 is provided with a brush roller 62.
An opening 64 communicating with the second carrying unit 44 of the recycling carrying unit 4 is formed at the bottom of the drop replenishing unit 61. The opening 64 is covered with a mesh 65, and the bristle tips of the brush roller 62 are The upper surface of the mesh 65 is contacted. The lower end of the wall 55 is a flicker portion 66 that bends toward the brush roller 62 and engages with the brush roller 62.

V. Toner Collection Section 7 In the toner collection section 7, the duct 71 is arranged along the bottom surface of the developing device, and a suction port 72 is formed at a portion facing the photoconductor 100. In addition, the duct 71 is the suction unit 7.
It is connected to a recovery device (not shown) via 3.

II. Operation In the above configuration, the main stirring unit 1 of the developer circulating stirring unit 1
1 and the sub-stirring portion 21 store a developer including toner and carrier, and the toner storing portion 51 stores toner. When the rotation of the drive motor (not shown) is transmitted to the drive gear 39, the bucket roller 12 rotates in the direction of arrow a via the gears 39 and 37, and the gear 3
The sleeve 33 rotates in the direction of the arrow c via 9, 36. Further, the rotation of the bucket roller 12 causes the gears 17 and 8 to rotate.
It is transmitted to the stirring and conveying member 24 via 6, 81, and the stirring and conveying member 24 rotates in the direction of arrow b. Further, the rotation of the gear 86 is transmitted to the cam 82 via the bevel gears 87 and 88, and the stirring / transporting member 24 periodically moves in the directions of arrows m and n based on the rotation of the cam 82. Furthermore, the first part of the recycle transfer unit 4 is connected via a gear (not shown).
The transport member 47 and the second transport member 48 are respectively indicated by arrows d and e.
Move in the direction. i. Therefore, in the sub-stirring section 21, in the sub-stirring section 21, as the stirring / transporting member 24 rotates in the direction of the arrow b, the developer in the left side area is screwed to the right side (direction of the arrow m) as shown in FIG. And the developer in the right area is mixed and conveyed by the screw 28b to the left (in the direction of arrow n), the developers in both areas merge around the restricting member 27, and the pushing member 26 rotates to rotate the central passage 20. Via the main stirring section 1
Sent to 1. In addition, the stirring and conveying member 24 is indicated by an arrow m,
By moving in the n direction, the pushing member 26 moves to the left and right, and the feeding position of the developer from the sub stirring unit 21 to the main stirring unit 11 changes. That is, as shown in FIG. 3, when the pushing member 26 is on the center line CL, the developer conveyed from the right side region of the sub stirring unit 21 is conveyed from the right side region and the left side region of the main stirring unit 11. The developing agent is sent to the left side area of the main stirring section 11.

However, as shown in FIG. 4, when the pushing member 26 is on the right side of the center line CL, the developer conveyed from the right side area of the sub stirring section 21 is sent to the right side area of the main stirring section 11. In addition to being discharged, the developer conveyed from the left side area is positively sent to the right side area based on the sending action of the pushing member 26. Further, as shown in FIG. 5, when the pushing member 26 is on the left side of the center line CL, the developer conveyed from the left side region of the sub stirring unit 21 is simply sent to the left side region of the main stirring unit 11. Instead, the developer conveyed from the right side area is positively sent to the left side area. Therefore, the developer in the left and right regions is positively mixed with the developer in the other region by the main stirring unit 11 and the sub stirring unit 21. Further, the weight mixing ratio of the toner to the carrier of the developer merged in the central portion (hereinafter, referred to as “toner concentration”) is detected by the toner concentration detection sensor 30, and as a result, the toner concentration of the developer is a predetermined reference value. In the following cases, the toner is replenished to the developer from the toner replenishing section 5.

Ii. Operation in Main Stirring Unit 11 In the main stirring unit 11, as the bucket roller 12 rotates in the direction of arrow a, the developer sent from the sub stirring unit 21 via the central passage 20 as shown in FIG. Are conveyed left and right by the feed blades 16a and 16b. The developer conveyed to the left and right areas of the main stirring section 11 is fed by the feed blade 1.
It is conveyed while being agitated at both ends by 6a and 16b. Further, based on the rotation of the bucket 15, the developer is lifted rearward along the bottom surface and passes through the passage 20 to cause the sub agitation unit 2 to move.
Sent to 1. Further, as shown in FIG. 1, the developer scooped by the bucket 15 in the main agitating unit 11 is conveyed in the direction of the arrow a, and the scraping member 49 provided in the structure 41 scrapes off the excess and supplies the developer. It is supplied to the developing roller 31 in the area A.

Iii. Operation in Developing Unit 3 The developer supplied to the developing roller 31 is held on the outer peripheral portion of the sleeve 33 by the magnetic force of the magnet body 32, is conveyed in the direction of arrow c as the sleeve 33 rotates, and is regulated by the first regulating plate 34. To be done. Then, the developer regulated by the first regulation plate 34 is sent to the recycling conveyance section 4 via the entrance 45. On the other hand, the developer that has passed through the tip of the first regulation plate 34 is continuously conveyed in the direction of arrow c while forming a magnetic brush along the magnetic lines of force generated from the magnetic poles. The developer conveyed to the opposing portion of the pole N _1, by where the magnetic field lines of the magnetic pole N ₁ is occurring toward the magnetic pole S _3, forms a reservoir at the opposite end of the magnetic pole N _1, this The developer, which cannot be retained due to the accumulation, sequentially flies over the non-magnetic pole portion M ₁ and is transported to a region (hereinafter, referred to as “developing region”) B where the photoconductor 100 and the sleeve 33 face each other. It should be noted that the developer that moves to the developing area B from the pool formed at the portion facing the magnetic pole N ₁ is regulated and directed by the second regulating plate 35, and the amount of the developer that enters the developing area B does not fluctuate and is stable. To do. In the developing area B, the developer comes into contact with the surface of the photoconductor 100, and if an electrostatic latent image is formed on the surface of the photoconductor 100, the toner is attached to the surface of the photoconductor 100 for development. In the developing area B, the developer retained on the sleeve 33 without adhering to the photoconductor 100 continues to be indicated by the arrow c.
Is released from the magnetic force of the magnet body 32 in the area facing the non-magnetic pole portion M ₂ , separated from the surface of the sleeve 33, and falls onto the main stirring portion 11.

Iv. Operation in Toner Collection Unit 7 In the toner collection unit 7, a duct 71 is provided by a collection device (not shown).
Air is sucked from the opening 72 via the
The toner that falls from the portion facing 00 is sucked into the opening 72. The toner sucked into the opening 72 receives the duct 72,
It is recovered by the recovery device via the suction unit 73.

V. Operation in Recycle Conveying Section 4 In the recycling conveying section 4, the developer conveyed to the first conveying section 43 is mixed by the first conveying member 47 and is sent to the second conveying section 44 over the wall 42. The developer in the second transport section 44 is mixed by the second transport member 48 while being dropped.
Sent to the main stirring path 11 and collected.

Vi. Operation in Toner Replenishing Section 5 When the toner replenishing section 5 confirms that the toner concentration of the developer is lower than the predetermined reference value based on the detection result of the toner concentration detecting sensor 30, the stirring blade 52, 53
Rotates in the directions of arrows f and g, the toner is mixed and stirred, and is sent to the drop replenishing unit 61 through the opening 56. In the drop replenishing section 61, the brush roller 62 rotates in the direction of arrow h, and the toner taken in by the brush roller 62 is conveyed in the direction of arrow h. Further, the brush roller 62 engages with the flicker portion 66 as it rotates, and the electrostatic attraction of the toner to the brush is released by the vibration when the engagement is released, and the toner is easily separated from the brush. Next, the toner is separated from the brush when the brush roller 62 comes into contact with the mesh 65, and is dropped and supplied to the recycle transport unit 4 through the mesh 65. At this time, the toner drops in a dispersed state, and when mixed with the developer mixed in the second transport unit 44, the toner quickly contacts the carrier and is charged.

The moving device for moving the stirring / transporting member 24 of the sub-stirring section 21 to the left and right is not limited to the above-mentioned embodiment, but may be as shown in FIGS. Here, FIG.
In the moving device 80 ', a shaft 25 protruding from the developing tank 10 is provided with a swash plate cam 90 having one side formed obliquely with respect to the shaft, and the swash plate cam 9 is urged by a biasing force of a spring 84.
The one side surface of No. 0 is in contact with the guide portion 91 provided in the developing tank 10. Therefore, when the agitating / conveying member 24 rotates, based on the engaging action of the swash plate cam 90 and the guide 91,
The stirring / transporting member 24 and the pushing member 26 periodically move in the axial direction, whereby the sub-stirring unit 21 moves to the main stirring unit 1.
The developer feeding position to 1 is periodically changed, and the developers in the left and right regions are mixed appropriately.

Further, the moving device 80 ″ of FIG. 7 is a further improvement of the moving device 80 ′ of FIG. 6, in which the shaft 13 of the bucket roller 12 is provided with the first belt wheel 92, while the stirring and conveying member 24 is provided. The shaft 25 is provided with a second belt wheel 93 having a wide belt winding portion in the axial direction.
A belt 94 is wound around 2,93. Therefore, when the bucket roller 12 rotates based on the rotation of the drive gear 39, the rotation of the bucket roller 12 causes the first belt wheel 92, the belt 93,
It is transmitted to the stirring and conveying member 24 via the second belt wheel 94. Further, when the stirring / transporting member 24 moves based on the engaging action of the swash plate cam 90 and the guide portion 91, the belt 94 axially moves on the outer periphery of the belt wheel 93 to allow the movement, whereby the left and right sides are moved. The developer in the area is mixed.

A comparative experiment was conducted on the developer agitation efficiency of the developing device and the conventional developing device having no moving device. In the experiment, the right end side of the stirring / transporting member 24 of the sub stirring unit 21 (position B
₁ ) (see FIG. 2), a predetermined amount of toner is charged, the respective developing devices are mounted on the same copying machine to develop the same image, and the right side end portion (corresponding to the toner charging position) B ₁ , The copy image densities of the portions corresponding to the right-side area central portion side B ₂ , the left-side area end portion A ₁ , and the left-side area central portion side A ₂ were measured for each predetermined number of sheets. As a result, in the developing device of the present invention equipped with the moving device, as shown in FIG. 8, the image densities of the portions corresponding to the positions B ₁ and B ₂ on the toner input side drastically decrease as the number of copies increases. The image densities of the portions corresponding to the positions A ₁ and A ₂ in the opposite area tend to increase sharply as the number of copies increases, and the number of copies is only 10%.
At the stage of 0 sheets, the image densities at the right end (B ₁ ) and the left end (A ₁ ) converged within a range of about 0.1. On the other hand, in the conventional developing device having no moving device, as shown in FIG. 9, the convergence of the image density is very slow, and when the number of copies is 100, the right end (B ₁ ) and the left end (A ₁ The image density difference of ₁ ) is about 0.
3, and even after that, when the number of copied sheets was 200, the image density difference was reduced to only about 0.2. From this experiment, it can be understood that in the developing device according to the present invention, the developers in the left and right regions in the sub-stirring part 21 and the main stirring part 11 are mixed rapidly and in a mixed manner, as compared with the conventional developing device.

Next, a toner density detecting sensor is provided in each of the left and right areas of the developing device of the present invention and the conventional developing device,
A document having an image only in a portion corresponding to one region with the center line CL of the developing device as a boundary and a document having no image in the other region is continuously copied to change the toner density in the left and right regions. It was measured. As a result, in the developing device of the present invention, as shown in FIG. 10, the toner density on the toner consuming side corresponding to the area with the image and the toner density on the toner non-consuming side corresponding to the area without the image are the same as the number of copies. The value was almost the same regardless of the increase. On the other hand, in the conventional developing device, as shown in FIG.
As shown in No. 1, the toner density on the toner consumption side showed a gradual decrease, but the toner density on the toner non-consumption side showed a gradual increase, and the difference in toner density between the left and right regions increased. The toner density on the toner consuming side increases because new toner is replenished from the toner replenishing device due to the lowering of the toner density, but the developer in the left and right areas does not mix and the toner non-consuming side increases. This means that the supplied toner is not supplied to the toner consuming side. Therefore,
From this experiment, it can be understood that in the developing device according to the present invention, the developers in the left and right regions are mixed rapidly and mixed.

[0025]

As is apparent from the above description, in the developer circulating and stirring apparatus according to the present invention, the first developer carrying path, the second developer carrying path adjacent to the first developer carrying path, and the first developer carrying path are provided. A first stirring / conveying member provided in the developer conveying path of
In the first developer transport path, the developer is transported from both end sides to the central portion based on the second stirring and transporting member provided in the developer transporting path and the driving of these stirring and transporting members. In the developer circulating agitation device, the developer circulating and agitating device is configured to send the developer to the first developer transport path and to transport the developer from the central portion to both end sides in the second developer transport path. A moving device that reciprocates along the first developer transport path is provided. Therefore, by moving the pushing member with the moving device, it is possible to improve the dispersibility of the toner by mixing the developers in the left and right regions of the main stirring unit and the sub stirring unit appropriately. Therefore, even when a document having a large number of image portions is continuously printed on one side, there is no inconvenience that the image density of the corresponding area is reduced, and an image with stable image density can be obtained as a whole.

[Brief description of drawings]

FIG. 1 is a sectional view of a developing device according to the present invention.

FIG. 2 is a plan view showing a state where a developer is circulated in a developer circulating and stirring section according to the present invention.

FIG. 3 is a diagram showing a movement of a developer in a sub stirring unit.

FIG. 4 is a diagram showing a movement of a developer in a sub stirring unit.

FIG. 5 is a diagram showing the movement of the developer in the sub agitation unit.

FIG. 6 is a diagram showing a second embodiment of the present invention.

FIG. 7 is a diagram showing Embodiment 3 of the present invention.

FIG. 8 is a diagram showing the circulation efficiency of the developing device according to the present invention.

FIG. 9 is a diagram showing the circulation efficiency of a conventional developing device.

FIG. 10 is a diagram showing a change in toner concentration in the sub-agitation unit of the developing device according to the present invention.

FIG. 11 is a diagram showing a change in toner concentration in a sub-agitation unit of a conventional developing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Developer circulation conveyance part, 3 ... Development part, 4 ... Recycling conveyance part, 5 ... Toner supply part, 7 ... Toner collection part, 11 ... Main stirring part, 12 ... Bucket roller, 16 ... Feed blade, 18
... drive gear, 21 ... sub-stirring section, 24 ... stirrer conveying member, 2
7 ... Regulating member.

Claims (1)

[Claims] 1. A first developer carrying path, a second developer carrying path adjacent to the first developer carrying path, a first agitating and carrying member provided in the first developer carrying path, and the second developer carrying path. On the basis of the second stirring / transporting member provided in the developer transporting path and the driving of these stirring / transporting members, the developer is transported from both end sides to the central portion in the first developer transporting path, In the developer circulating and stirring device, the developer circulating agitator is configured to send the developer to the second developer carrying path, and to carry the developer back to the first developer carrying path from the central portion in the second developer carrying path. A developer circulating / stirring device comprising: a moving device that reciprocates the first stirring / transporting member along a first developer transporting path.