JP2002351215A - Developing device, image forming device and developing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems that it was difficult in the past to adjust the necessity of adjusting among a developer conveying quantity of a developer carrier, a supplying quantity to the developer carrier, and recovering quantity from the developer carrier, even though it is possible to form an image of uniform density in a developing device of one circulation system. SOLUTION: To attain the above mentioned adjustment by executing an actuating control of a supply means and a recovery means, and stop control at proper timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus for forming an image by an electrophotographic method, a developing device incorporated in the image forming apparatus, and a developing method.

[0002]

2. Description of the Related Art (1) As a developing device of an image forming apparatus for forming an image by an electrophotographic system, a developing device using a two-component developer containing a toner and a carrier is widely used.

A developing device using a two-component developer transports the developer to a developing area, and carries a developer carrying member that carries the developer in the developing area, a supply unit that supplies the developer to the developer carrying body, and a developer after developing. A collecting section for collecting the developer from the developer carrier is a main component.

In the development, it is important that the toner density does not fluctuate with time and that the density of the image forming body carrying the latent image to be developed does not vary in the moving direction. It is important that the toner density in the developer is uniform so that density unevenness does not occur in a direction perpendicular to the direction (hereinafter, referred to as an image width direction).

On the other hand, since the toner is replenished at one place in the developing device, various devices have been devised such as using a stirring screw to uniformly disperse the replenished toner in the developer.

[0006] Japanese Patent Application No. 2000-343075 discloses that the developer recovered from a developer carrier in a recovery section is returned to a stirring / transporting / feeding section in which toner is supplied without returning to a supply section, so that the image width direction is reduced. There has been proposed a developing device in which a developer having a uniform toner concentration is supplied to a supply portion, and the developer having a uniform toner concentration is supplied from the supply portion to a developer carrier.

(2) Characteristics of the developer, that is, the bulk density, fluidity, Q / M (charge amount of toner, μC / g
Is known to change as the operation time of the developing device elapses. Since such a change in the characteristics of the developer affects the density of an image formed by development, the control of toner replenishment may be changed between the start of operation of the image forming apparatus in the first morning and after the operation is repeated. Measures have been taken.

(3) As a means for detecting the toner concentration of a developer for the purpose of toner replenishment control, a means for measuring the magnetic permeability of the developer is widely used. However, since the magnetic permeability of the developer varies not only with the toner concentration but also with the usage of the developer, a technique for detecting only a change in the magnetic permeability due to a change in the toner concentration, or correcting the measured magnetic permeability. Technology has been developed.

[0009]

(1) A conventional developing device, that is, a developer recovered from a developer carrier is stirred and
For the developing device dispersed and returned to the transport unit and the supply unit,
The developing device proposed in Japanese Patent Application No. 2000-343075, that is, all of the developer recovered from the developer carrier,
The developing device of the type in which the developer is returned from the stirring / conveying section to the stirring / transporting section and the developer is supplied from the stirring / conveying section enables the toner density in the image width direction to be uniform, thereby enabling to form an image having a uniform density. . In such a developing device, matching between the amount of developer supplied from the supply unit, the amount of developer transported by the developer carrier, and the amount of developer collection and transport in the recovery unit is established. is important. If the alignment is broken, a shortage or excess of the developer may occur, which may affect the image quality and the operation of the developing device.

Incidentally, it is possible to obtain a constant image density by changing the moving speed of the developer carrier in response to a change in image density due to a change in various characteristics (for example, a change in the characteristics of a developer or a photoreceptor). For this purpose, it is desirable to separately provide a developing unit driving unit for driving the developer carrier and a collecting unit driving unit for driving the collecting unit. However, when the developing unit driving unit and the collecting unit driving unit are separately provided,
In some cases, the developer is accumulated in the collecting section, and further, packing occurs in which the accumulated developer is solidified.

This is because even if the developing unit driving means and the collecting unit driving means are turned off at the same time when the developing device is stopped, the developer carrier may rotate even after the collecting unit is stopped due to inertia. This is caused by the developer being transported from the developer carrying member to the collection section whose operation has been stopped.

A first object of the present invention is to prevent the above-mentioned undesired phenomena occurring when the developing device is stopped, to prevent the developer from being accumulated in the collecting section, and to form a high-quality image. It is an object of the present invention to provide a developing device and an image forming apparatus which perform the following.

(2) In the developing device described in the above-mentioned Japanese Patent Application, when the developing unit driving means and the supply unit driving means are separately provided, the amount of the developer conveyed to the developing area when the developing device is started up. However, there is a problem that image quality is impaired due to instability.

This is because even if the developing unit driving means and the supply unit driving means are turned on at the same time when the developing device is started, if there is a difference between the rising characteristics of the developer carrier and the rising characteristics of the supply unit, the This is a phenomenon in which image unevenness occurs because the amount of developer supplied to the developer carrier may be insufficient.

A second object of the present invention is to provide a developing apparatus and an image forming apparatus for forming a high-quality image by preventing the above-mentioned undesirable phenomenon occurring when the developing apparatus is started. I do.

(3) Conventionally, in response to a change in the characteristics of the developer, control is performed to change the operating conditions between the start of operation such as in the morning and a stable state after a certain amount of operation. Not enough. In particular, it has been found that an undesirable phenomenon occurs due to a change in the bulk density of the developer at the start of operation and during stable operation of the image forming apparatus.

That is, since the substantial amount of the developer conveyed by the developer carrying member fluctuates due to the change in the bulk density, in the developing device described in the above-mentioned Japanese Patent Application, the supply amount of the supply portion and the developer carrying amount It has been found that the matching between the amount of body transported and the amount collected by the collection unit is broken, and the problem that the accumulation of the developer in the collection unit or the shortage of the amount of the developer in the supply unit is likely to occur. . Another problem is that the image density changes.

A third object of the present invention is to provide a developing apparatus and an image forming apparatus which can solve the above-mentioned problems caused by a change in the characteristics of the developer and can stably form a high quality image. The purpose is to do.

(4) With respect to correction for fluctuation factors other than the toner density, a method of predicting a fluctuation value in advance, determining a correction value, and performing correction has been adopted, but such correction is not sufficient. Absent. Particularly, in a color image forming apparatus, when an image is formed on a thick paper or an OHP sheet, the conveying speed of the recording material in the fixing device is reduced in order to secure the fixing property and to form a glossy image. However, since the operating speed of the photoconductor and the developing device is reduced in response to the reduction in the fixing device, the degree of stirring of the developer changes, and the bulk density of the developer changes. Since the output of the toner density detecting means for detecting a change in magnetic susceptibility changes, the conventional correcting means cannot perform an appropriate correction.

In particular, when the development is performed using the developing device and the polymerized toner described in the above (1) and (2), the conventional correction means is insufficient.

A fourth object of the present invention is to solve the above-mentioned problem of the prior art when toner density is detected by measuring magnetic permeability and toner replenishment control is performed based on the detection result. It is an object to provide a developing device and an image forming apparatus that can form an image.

[0022]

The object of the present invention described above is achieved by the following invention.

1. A developer carrying member that transports the developer to the developing region and carries the developer in the developing region, a supply unit provided with a supply unit that supplies the developer to the developer carrying member, and develops the developer from the developer carrying member. A collection unit provided with a collection unit for collecting the developer, wherein the supply unit and the collection unit are separated at least in an image area, and at least a developing unit driving unit that drives the developer carrier. In a developing device in which a collecting unit driving unit that drives the collecting unit is separately provided, such that a stop time of the developer carrier is simultaneous with or before a stop time of the collecting unit.
A developing device provided with control means for controlling the developing section driving means and the collecting section driving means.

2. 2. The developing device according to claim 1, wherein the control unit controls the turning off of the developing unit driving unit before the turning off time of the collecting unit driving unit.

3. Wherein the control means applies a brake to stop the developing unit driving means.
Or the developing device according to the above item 2.

4. The developing device according to any one of claims 1 to 3, wherein the developing unit driving unit includes a DC motor, and the collection unit driving unit includes a stepping motor.

5. A developer carrying member that transports the developer to the developing region and carries the developer in the developing region, a supply unit having a supply unit that supplies the developer to the developer carrying member,
A collection unit having a collection unit for collecting the developer from the developer carrier, wherein the supply unit and the collection unit are separated at least in an image area, and at least drive the developer carrier. A developing device in which a developing unit driving unit and a supplying unit driving unit that drives the supplying unit are separately provided, and an on time of the developing unit driving unit is simultaneously or simultaneously with an on time of the supplying unit driving unit. A developing device, comprising: a control unit that controls the developing unit driving unit and the supply unit driving unit.

6. The developing device according to claim 5, wherein the developing unit driving unit has a DC motor, and the supply unit driving unit has a stepping motor.

7. 6. The developing device according to claim 5, wherein a recovery unit driving unit that drives the recovery unit of the recovery unit is also used as the supply unit driving unit.

8. 8. The developing device according to claim 1, wherein the supply unit is disposed below the collection unit. 9.

9. The developing device according to any one of the above items 1 to 8, wherein the development is performed using a polymerized toner.

10. A developer carrying member that transports the developer to the developing region, carries the developer in the developing region, a developing unit driving unit that drives the developer carrying unit, and a supply unit that supplies the developer to the developer carrying unit. And a regulating unit that regulates the amount of developer on the developer carrying member, the developing device being transported to the developing region by changing the rotation speed of the developing unit driving unit. A developing device, comprising: a control unit that performs control for maintaining a constant rate of transport of the developer.

11. The developing device according to claim 10, further comprising a collecting unit provided with a unit for collecting a developer from the developer carrier, wherein the supply unit and the collecting unit are separated at least in an image area. apparatus.

12. The developing device according to claim 11, wherein the supply unit is disposed below the collection unit.

13. The developing device according to any one of claims 10 to 12, wherein the regulating unit regulates an amount of the developer on the developer carrier to 70 mg / cm ² or less.

14. An image forming apparatus comprising: an image forming body; a latent image forming means for forming an electrostatic latent image on the image forming body; and the developing device according to any one of 1 to 13 above.

15. An image forming body, a latent image forming unit for forming an electrostatic latent image on the image forming body, and a two-component magnetic developer conveyed to a developing area by a developer carrier to form an electrostatic latent image on the image forming body. Developing device, toner concentration detecting means for detecting the toner concentration of the two-component magnetic developer by measuring the magnetic permeability of the two-component magnetic developer in the developing device, and toner supply for replenishing toner to the developing device Means for controlling the toner replenishing means based on an output of the toner concentration detecting means, wherein the control means is configured to perform control based on data set for each recording material conveyance speed. An image forming apparatus for controlling the toner replenishing means by changing a threshold value in control or changing an output value of the toner density detecting means.

16. A storage unit for storing the data obtained from the operation experiment of the developing device, wherein the storage unit stores, based on an output value of the toner density detection unit for each recording material conveyance speed at an initial adjustment when a developer is supplied. The data of a control threshold value of the control unit, a control voltage for changing an output value of the toner density detection unit, or a correction value of an output of the toner density detection unit obtained by calculation is stored. 16. The image forming apparatus according to item 15.

17. The developing device has a weight average particle size of 3
The amount of magnetization in a non-magnetic toner of ８8 μm and a magnetic field of 79 × 10 ³ A / m is 3.8 × 10 ^{-5 to} 8.8 × 10 ^-5 wb.
17. The image forming apparatus as described in 15 or 16 above, wherein development is performed using a two-component developer containing a carrier having a m / kg and a weight average particle diameter of 30 to 70 μm.

18. The image forming apparatus according to any one of Items 15 to 17, wherein the nonmagnetic toner is a polymerized toner.

19. Developing method for developing an electrostatic latent image on an image forming body by controlling toner replenishing means for replenishing toner to a developing device based on an output of a toner density detecting means for detecting a toner density in a two-component magnetic developer And controlling the toner replenishing unit by changing a threshold value for driving the toner replenishing unit or changing an output of the toner density detecting unit based on data set for each moving speed of the image forming body. A developing method.

20. Non-magnetic toner having a weight average particle diameter of 3 to 8 μm and a magnetization amount in a magnetic field of 79 × 10 ³ A / m of 3.8 × 10 ^{−5 to} 8.8 × 10 ⁻⁵ wb · m / kg; 20. The developing method as described in 19 above, wherein a two-component developer containing a carrier having an average particle diameter of 30 to 70 μm is used.

21. 21. The developing method according to 19 or 20, wherein the non-magnetic toner is a polymerized toner.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A configuration of a color copying machine as an example of an image forming apparatus according to an embodiment of the present invention, on which a plurality of sets of developing devices according to the embodiment of the present invention are mounted, will be described.

<Structure of Image Forming Apparatus> FIG. 1 is an overall structural diagram of a color copying machine according to an embodiment of the present invention, comprising an image forming apparatus main body GH and an image reading apparatus YS.

The image forming apparatus main body GH includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, a belt-shaped intermediate transfer body 6, a sheet feeding and conveying unit, and a fixing device 24.

Image forming unit 1 for forming a yellow image
0Y includes a charging unit 2Y, an exposing unit 3Y, a developing unit 4Y, and a cleaning unit 8Y arranged around a photoreceptor 1Y as an image forming body. An image forming unit 10M that forms a magenta image includes a photoconductor 1M as an image forming body,
It has a charging unit 2M, an exposure unit 3M, a developing device 4M, and a cleaning unit 8M. The image forming unit 10C for forming a cyan image has a photoreceptor 1C as an image forming body, a charging unit 2C, an exposing unit 3C, a developing unit 4C, and a cleaning unit 8C. Image forming unit 1 for forming a black image
0K is a photoconductor 1K as an image forming body, a charging unit 2K,
Exposure unit 3K, developing unit 4K and cleaning unit 8K
Having. Charging means 2Y and exposure means 3Y, 2M and 3M,
2C and 3C and 2K and 3K constitute a latent image forming unit.

The intermediate transfer member 6 is wound around a plurality of rollers and is rotatably supported. Image forming unit 10Y,
Images of each color formed from 10M, 10C, and 10K are:
Transfer means 7Y, 7M, 7C, on the rotating intermediate transfer body 6,
The images are sequentially transferred by 7K (primary transfer), and a combined color image is formed. The recording material P accommodated in the paper cassette 20 is fed by the paper feeding means 21 and is conveyed to the transfer means 7A via the paper feeding rollers 22A, 22B, 22C, the registration rollers 23, etc. The color image is transferred (secondary transfer). The recording material P to which the color image has been transferred is subjected to a fixing process by a fixing device 24, and is sandwiched by sheet discharging rollers 25 and placed on a sheet discharging tray 26 outside the apparatus.

On the other hand, after the color image is transferred to the recording material P by the transfer means 7A, the intermediate transfer body 6 from which the recording material P is separated by curvature is cleaned by the cleaning means 8A.

5Y, 5M, 5C and 5K are the developing devices 4
A toner replenishing unit that replenishes new toner to Y, 4M, 4C, and 4K.

An image reading device YS comprising an automatic document feeder 201 and a document image scanning and exposing device 202 is provided above the image forming apparatus main body GH. The document d placed on the document table of the automatic document feeder 201 is conveyed by a conveying means, and one side or both sides of the document is scanned and exposed by the optical system of the document image scanning and exposing device 202, and is scanned by a line image sensor CCD. Image reading is performed.

The analog signal photoelectrically converted by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing and the like in an image processing section, and then to an image writing section (exposure means) 3Y. 3
Send signals to M, 3C, 3K.

The automatic document feeder 201 has an automatic double-sided document conveying means. The automatic document feeder 201 can continuously read the contents of a large number of documents d fed from the document table and accumulate them in the storage means (electronic RDH function). It is conveniently used when copying a large number of documents or when transmitting a large number of documents d by a facsimile function.

<Structure of Developing Apparatus> FIG. 2 is a central sectional view of the developing apparatus according to the embodiment of the present invention. Hereinafter, the developing devices 4Y, 4M, 4C, and 4K are referred to as developing devices 4.

The developing device 4 includes a developing device frame 40, a developer carrying member 41 composed of a developing roller, a magnetic field generating means (magnet roll) 42, a regulating means 43 composed of a cutting board, a water wheel type supplying means 44, and a screw. And a stirring / conveying means 46 comprising a screw, a conveying roller 47, a stripping plate 48, a collecting means 49 comprising a screw, a toner concentration sensor TS as a toner concentration detecting means, and the like.

The developer carrying member 41 is arranged to face the image forming member 1 carrying an electrostatic latent image, is rotatably supported, and rotates as shown by the arrow to move the developer to the developing region DR.
To form a layer of the developer necessary for development by carrying the developer in the development region DR.

The magnetic field generating means 42 is arranged inside the developer carrier 41 and has a plurality of magnetic poles N1, N2, S1, S2,
S3. Two magnetic poles S2 and S3 adjacent to each other among the plurality of magnetic poles of the magnetic field generating means 42 are arranged with the same polarity to form a repulsive magnetic field. Magnetic pole S2 for removing developer
Removes and scatters the developer on the developer carrier 41. The developer receiving magnetic pole S <b> 3 sucks the developer supplied by the supply unit 44 and attaches the developer onto the developer carrier 41.

The supply means 44 is a rotatable water wheel type transport means for supplying the developer to the developer carrier 41, and the developer transported from the supply / transport means 45 is supplied to the developer carrier 4.
No. 1 is uniformly supplied near the developer receiving magnetic pole S3.
Note that the supply unit 44 may be a screw having a transport function in the rotation axis direction.

The supply / conveyance means 45 is disposed in parallel with the supply means 44, and conveys the developer conveyed from the stirring / conveyance means 46 to the supply means 44 while conveying the developer in the direction of its rotation axis.

The agitating / conveying means 46 mixes the replenished new toner and the developer refluxed from the supplying / conveying means 45, agitates and transports the mixed toner to an upstream portion of the supplying / conveying means 45.

In the vicinity of the developer stripping magnetic pole S2 of the developer carrier 41, a transport roller 47 is disposed. The transport roller 47 includes a rotatable rotating member (sleeve) 47.
A and the developing device main body 4 housed inside the rotating member 47A.
And a columnar magnet body 47B fixed to zero. The magnet body 47B includes, for example, five magnetic poles of N1, N2, S1, S2, and S3. The magnetic pole N1 faces the developer stripping magnetic pole S2 of the developer carrier 41 and is adjacent to the two magnetic poles S2 and S2.
3 forms a repulsive magnetic field of the same polarity.

The tip of the stripping plate 48 is close to or slightly in contact with the magnetic pole S2. The stripping plate 48 and the transport roller 47 form stripping means. The developer released from the surface of the developer carrier 41 by the developer stripping magnetic pole S2 of the developer carrier 41 is attracted by the magnetic pole N1 in the transport roller 47, and is carried and transported by the rotating rotating member 47A. In the vicinity of the magnetic pole S <b> 2, it is stripped off by the stripping plate 48 and falls into the collection unit 403.

The collecting means 49 rotatably arranged in the collecting section 403 collects and collects the developer which has been peeled off and dropped by the transport roller 47 and the peeling plate 48, and is supplied and supplied.
The developer is transported downstream of the image forming area G of the developer carrier 41 on the downstream side in the transport direction of the transport unit 45. If the developer does not return to the developer carrier 41, the collected developer is supplied to the downstream of the supply / transport unit 45 in the transport direction and into the development area of the developer carrier 41. Is also good. Alternatively, the developer recovered by the recovery unit 49 may be returned to the upstream of the stirring / transporting unit 402.

Supply / transportation means 45, stirring / transportation means 46
Each of the collecting means 49 is formed of a spiral screw, transports the developer in the rotation axis direction while stirring the developer, and discharges the developer in a direction substantially perpendicular to the rotation axis.

The developing device frame 40 includes a developer carrier 41,
A lower frame 40A that supports the transport roller 47, the supply unit 44, the supply / transport unit 45, and the stirring / transport unit 46, and a middle frame 40B that supports the stripping plate 48 and the collection unit 49.
And an upper lid 40C for closing the upper opening of the middle frame 40B.

The lower frame 40A forms a supply section 401 for accommodating the supply means 44 and the supply / conveyance means 45, and a stirring / conveyance section 402 for accommodating the stirring / conveyance means 46. The supply unit 401 and the stirring / transporting unit 402 are formed on both sides of the first partition 404 that stands upright from the bottom of the lower frame body 40A.

The second partition 405 formed at the bottom of the middle frame 40B that rotatably supports the collecting means 49 is
01 and the collection unit 403. A part of the middle frame 40B closes the upper opening of the stirring / transporting unit 402.

The downstream side of the developer transport of the recovery section 403 and the downstream side of the developer transport of the supply section 401 communicate with each other through a first opening 406 formed near the end of the second partition 405.

The downstream side of the developer transport of the supply unit 401 is agitated
The upstream side of the developer transport of the transport section 402 is the first partition 404.
Are communicated by a second opening 407 formed in the vicinity of one end (shown in FIG. 4).

The downstream side of the developer transport of the stirring / transport section 402 and the upstream side of the developer transport of the supply section 401 are connected to the first partition 404.
Are connected by a third opening 408 formed near the other end (shown in FIG. 4).

The toner concentration sensor TS provided at the bottom of the supply section 401 on the downstream side of the developer conveyance detects the toner density of the conveyed developer by measuring the magnetic permeability of the developer. In response to the toner concentration detection signal, the control unit 100 drives the toner replenishing unit 51 to agitate and transport the new toner
02 is supplied to the toner supply opening 409 provided near the upstream side of the developer conveyance. Note that it is also possible to optically detect the density of a developed image and perform toner replenishment control based on the detection result of the image density.

The developer peeled off by the transport roller 47 and the peeling plate 48 is recovered in the recovery section 403, and the recovered developer is transported to the downstream side of the developer transport by the recovery means 49, and is transferred to the second partition 405. The liquid flows back into the supply unit 401 from the first opening 406 provided.

The developer in the supply section 401 is conveyed by the supply / conveyance means 45 into the stirring / conveyance section 402 from the second opening 407 formed in one end of the first partition 404. The developer conveyed into the stirring / conveying section 402 is conveyed by the stirring / conveying means 46 while mixing and stirring the toner supplied from the toner supply opening 409 and the developer. The gas is discharged from the third opening 408 formed in the other end and returned to the supply unit 401.
In the supply unit 401, the developer is conveyed in the axial direction by the supply / conveyance unit 45, discharged, and supplied to the supply unit 44. The supply means 44 supplies the developer to the developer carrier 41 while radiating the developer while conveying it in the axial direction.

The first opening 40 provided near the end of the second partition 405 that separates the collecting section 403 from the supply section 401.
6, and a second opening 4 provided near both ends of the first partition 404 separating the supply unit 401 and the stirring / transporting unit 402
07 and the third opening 408 are both arranged outside the image forming area GR of the developer carrier 41.

The rotation direction of the supply means 44 and the supply / conveyance means 45 is set to be the same as the rotation direction of the developer carrier 41, so that the efficiency of the developer supply to the developer carrier 41 is improved. Not only is achieved, but also stable developer supply becomes possible, and a good image can be obtained.

The direction of rotation of the collecting means 49 is reversed from the direction of rotation of the developer carrier 41 so that
It is possible to reduce the backflow of the developer in the area 3.

In the developing device described above, it is preferable to use a two-component developer containing a non-magnetic polymerized toner and a small-diameter magnetic carrier. Particularly, such a two-component developer has a magnetization amount of 3.8 in a magnetic field of 79 × 10 ³ A / m.
× 10 ^{−5 to} 8.8 × 10 ⁻⁵ wb · m / kg, a carrier having a weight average particle diameter of 30 to 70 μm, and a nonmagnetic polymerized toner having a weight average particle diameter of 3 to 8 μm. A two-component developer is preferable, and it is preferable to apply a developing bias in which an alternating electric field is superimposed on the developer carrier 41 to develop the electrostatic latent image on the photoconductor 1.

When the weight average particle size of the carrier is smaller than 30 μm, carrier adhesion is likely to occur, and
If it is larger than μm, the image quality is liable to be deteriorated, for example, the density unevenness called a dent is generated in the image.

When the weight average particle diameter of the toner is smaller than 3 μm, the image quality is easily deteriorated due to fogging and the like, and when it is larger than 8 μm, the characteristic of high image quality is reduced.

The polymerized toner is a toner obtained by forming a toner binder resin and forming the toner shape by polymerization of a raw material monomer or prepolymer of the binder resin and subsequent chemical treatment. More specifically, it means a toner obtained through a polymerization reaction such as suspension polymerization or emulsion polymerization and, if necessary, a step of fusing particles together. In the polymerized toner, since the raw material monomer or prepolymer is polymerized after being uniformly dispersed in an aqueous system,
A toner having a uniform particle size distribution and shape of the toner can be obtained.

The weight average particle diameter of the carrier and the weight average particle diameter of the toner are average particle diameters on a mass basis, and are “Coulter Counter TA-11” or “Coulter Multisizer” equipped with a wet disperser. These are values measured by Coulter Corporation.

FIG. 3 shows a drive control system of the developing device 4. The developer carrier 41 and the transport roller 47 are driven by a motor M1 as a developing unit driving unit,
The supply / transportation unit 45, the stirring / transportation unit 46, and the collection unit 49 are driven by a motor M2 which is also used as a supply unit drive unit and a collection unit drive unit. Developer carrier 4
1, the braking force by the restricting means 43 acts,
A motor having a relatively large driving torque is used as the motor M1. Therefore, it is preferable to use a DC motor as the motor M1. On the other hand, the supply means 44
The motor M2 for driving the collecting means 49 may be a DC motor, but is preferably a stepping motor so that the developer can be changed while being reversely rotated at a desired interval and ratio with high accuracy.

The electrostatic latent image is developed in the developing region DR by the counterclockwise rotation of the photosensitive member 1 indicated by the arrow and the clockwise rotation of the developer carrier 41 indicated by the arrow. A developing bias in which a DC bias having the same polarity as the polarity of the latent image is superimposed on the AC bias is supplied to the developer carrier 41 by a bias power source B.
S is applied, and reversal development is performed.

The rotation speed of the photosensitive member 1 and the developer carrier 41 is changed depending on the image forming mode. That is, in a mode in which an image is formed on thick paper or OHP, the rotation speed of the photosensitive member 1 and the developer carrier 41 is reduced to about a fraction of that in the normal mode. Image formation is performed. In such a change of the image forming mode, it is desirable to change the speed while maintaining the ratio of the rotation speed of the photoconductor 1 to the rotation speed of the developer carrier 41 in order to maintain the developing property constant. .

<Circulation of Developer and Replenishment of Toner> The circulation of the developer will be described with reference to FIG. 4 showing a developer circulation system.

(1) On the upstream side of the stirring / transporting section 402, the developer refluxed from the supply section 401 and the recovery section 403 and the new toner are carried in, and are stirred and mixed by the stirring / transporting means 46, and are indicated by arrows. The developer is transported in the developer movement direction indicated by V1.

(2) The mixed developer passes through the third opening 408 on the downstream side of the stirring / transporting section 402 and is supplied to the supply section 4.
01 upstream. In the supply unit 401,
The developer is conveyed to the supply unit 44 as indicated by an arrow V3 while being conveyed by the supply / conveyance unit 45 in the developer movement direction indicated by the arrow V2.

(3) The supply means 44 does not have a transport function in the rotation axis direction, and transports the developer transported from the supply means 44 to the developer carrier 41 as shown by an arrow V4.

(4) The developer on the developer carrier 41 develops an electrostatic latent image on the photoconductor 1 in a development area DR (shown in FIG. 2) facing the image carrier 1. The developer indicated by the white arrow whose toner concentration has decreased due to the development is collected by the collection unit 403.
The transfer roller 47 is peeled off from the developer carrier 41 as indicated by an arrow V5, and moves on the transfer roller 47.

(5) The collected developer on the transport roller 47 is
It is peeled off by the peeling plate 48 and housed in the collecting section 403 as shown by an arrow V6.

(6) The recovered developer stored in the recovery section 403 is transported by the rotating recovery means 49 as shown by an arrow V7.

(7) The collected developer is collected in the collecting section 403.
Discharged from the first opening 406 on the downstream side,
Is carried out outside the image area GR on the downstream side as shown by the arrow V8.

(8) The developer supplied to the first opening 406 of the supply unit 401 is transported as shown by an arrow V9,
After the toner concentration is detected by the toner concentration sensor TS, the toner passes through the second opening 407 and is introduced upstream of the stirring / transporting unit 402 as indicated by an arrow V10.

(9) In the agitating / conveying section 402, toner replenishment is performed by the first toner replenishing means 51 according to the toner density detection signal of the toner density sensor TS, and the developer joins the arrow V1.

The developer is conveyed in the circulation system as described above, and a part of the developer is supplied to the supply section 401 and the stirring / conveyance section 402.
It circulates between the points as indicated by arrows V1, V2, V9 and V10.

As is clear from the above description, after the developer is recovered from the developer carrier 41 to the recovery unit 403, the developer is not returned to the supply unit 401 in the image area GR, but as shown by an arrow V8, The flow returns to the supply unit 401 outside the image area GR. Then, the developer carrier 41 is supplied from the supply unit 401.
After the toner is replenished, the developer
This is sufficiently stirred and uniformed in the transport unit 402 and the supply unit 401.

As described above, the structure is such that the developer recovered from the developer carrier 41 does not recirculate to the supply section 401 in the image area GR.
Hereinafter, a developer circulation system in which the developer recovered from the developer carrier is not directly mixed into the developer supplied to 1 is referred to as a single circulation system.

<Embodiment 1> FIG. 5 shows control timings of a developer carrier and a collecting means in Embodiment 1 in comparison with a conventional one.

In a one-circulation type developing device, it is important that the amount of developer transported in the developer carrier 41 and the amount of developer transported in the supply unit 401 and the recovery unit 403 are matched. . If this alignment is lost, supply of the developer to the developer carrier 41 becomes insufficient,
Is more likely to occur.

The rotation speed of the developer carrier 41 is variably controlled in relation to the image forming process.
Even when the rotation speed 1 changes, it is desirable that the stirring and conveyance of the developer be kept constant to maintain the characteristics of the developer.

For these reasons, as described above, the developing unit driving means for the developer carrier 41 and the conveying roller 47 and the supplying units for the supply means 44, the supply / conveyance means 45, the stirring / conveyance means 46 and the recovery means 49 are provided. The driving unit and the collection unit driving unit are provided separately like the motors M1 and M2.

FIG. 5A shows a conventional stop control of the motors M1 and M2. In the conventional driving method, as shown in the figure,
The driving signal DDS of the motor M1 and the driving signal D of the motor M2
RS and zero at the same time. That is, the motors M1 and M
2 were simultaneously turned off at time t1.

According to such a control method, FIG.
As shown in (2), the difference between the falling characteristic of the developer carrying member 41 and the falling characteristic of the collecting means 49 causes a phenomenon that the stopping time t3 of the developer carrying member 41 is later than the stopping time t2 of the collecting means 49. Occurs. In particular, when a DC motor is used as the motor M1 and a stepping motor is used as the motor M2, the above-described phenomenon becomes remarkable due to a difference in fall characteristics of each motor.

As a result, the developer is supplied to the collection unit 403 even after the collection unit 49 stops, and the collection unit 403 is supplied with the developer.
The phenomenon that the developer accumulates in the stagnation occurs. As the accumulation progresses, the developer accumulates up to the leading end of the stripping plate 48, lowering the stripping performance of the stripping plate 48, causing the developer to pass through the stripping plate 48 and developing the collected developer. The phenomenon of flowing back to the agent carrier 41 occurs. As the accumulation further progresses, a packing phenomenon in which the developer in the collection unit 403 solidifies may occur.

To make the developing device 4 compact, for example,
When the diameter of the screw constituting the collecting means 49 is set to 20 mm or less, accumulation of the developer and packing are particularly likely to occur.

In the present embodiment, in order to prevent such an undesired phenomenon, control is performed such that the stop time of the developer carrying member 41 is the same as or after the stop time of the collecting means 49.

One example is shown in FIGS. 5C and 5D. When the control means 100 turns off the motor M1,
That is, the time t when the drive signal DDS of the motor M1 is set to zero.
Control is performed such that 1 is set before the time point when the motor M2 is turned off, that is, the time point t2 when the drive signal DRS of the motor M2 is set to zero. By this control, as shown in FIG. 5D, the stop time t3 of the developer carrier 41 is changed to the stop time t of the collection unit.
Prior to step 4, the accumulation of the developer is prevented.

FIG. 6 shows another example of the present embodiment for preventing the phenomenon that the developer accumulates in the collecting section 403. In the present example, the control unit 100 turns off the motor M2 at the time point t1, supplies the reverse rotation drive signal DGS to the motor M1 a little later than the time point t1, applies a brake, and stops the motor M1. With this control, the developer carrier 41 and the collecting unit 49 are stopped at the same time at the time t2.

<Second Embodiment> FIG. 7 shows control timings of a developer carrier and a supply means in the first embodiment in comparison with a conventional one. 7 is controlled by the control means 10 shown in FIG.
Performed by 0.

In a one-circulation type developing device, it is important that the amount of developer transported in the developer carrier 41 and the amount of developer transported in the supply unit 401 and the recovery unit 403 are matched. . If the alignment is broken, the supply of the developer to the developer carrier 41 becomes insufficient,
Is more likely to occur.

In particular, in the configuration of the developing device 4 which is a one-circulation system in which the supply unit 401 is disposed below the recovery unit 403 and the developer is supplied to the developer carrier 41 from below, the supply amount is insufficient. It is important to eliminate

In the present embodiment, as shown in FIG. 7, the time when the motor M2 is turned on, that is, the time when the current supply to the motor M2 is started is determined by the time t when the motor M1 is turned on.
1 (FIG. 7 (a)) or after (FIG. 7 (c)) t2
By doing so, the shortage of the amount of developer transported to the developer carrier 41 is prevented. Particularly, in the present embodiment, the DC motor is used as the motor M1 and the stepping motor is used as the motor M2 as described above, so that the control shown in FIGS.
As shown in (b) and (d), the time point t4 at which the rotation speed of the developer carrier 41 reaches the steady state is surely later than the time point t3 at which the supply unit 44 reaches the steady state, and the developer is supplied. The shortage is resolved.

<Embodiment 3> It has been confirmed that the amount of the developer conveyed by the developer carrier 41 varies depending on the operation of the image forming apparatus, specifically, the operation of the developing apparatus 4. FIG. 8 shows the unit area (c) of the developer carrier 41.
The developer amount Dws (mg) per m ² ) is a value measured by operating the image forming apparatus. In the figure, the vertical axis represents the mass Dw of the developer on the developer carrier 41 per unit area.
The horizontal axis indicates the moving distance (km) of the surface of the developer carrier 41. A curve C1 shows a tendency of a change in the amount of developer transported immediately after the start of the image forming apparatus in the morning of a day called "morning one". 4 shows a tendency of a change in the amount of developer transported when is stabilized. As is clear from FIG. 8, the developer transport amount differs between immediately after the image forming apparatus has been stopped for a long time as in the morning and when the image forming apparatus has stabilized after the operation history, and the developer transport amount and the The amount of developer transported at the time of stabilization also changes with the movement distance of the developer carrier 41, in other words, as the operation time of the image forming apparatus elapses.

As a result, a phenomenon occurs in which the amount of the developer supplied to the developing region DR changes and the image density fluctuates. Further, in a single-circulation developing device, the developer carrier 41
The consistency between the amount of the developer transported by the developer, the amount of the developer supplied by the supply unit 44, and the amount of the developer recovered by the recovery unit 49 is broken, and the amount of the developer on the developer carrier 41 is insufficient. Undesirable phenomena such as accumulation of the developer in the collection unit 403 and the collection unit 403 are likely to occur.

In the present embodiment, in order to prevent the undesirable phenomenon as described above, the control means 100 controls the developer transport ratio Drate represented by the following equation (1) to be constant. I have. Specifically, the motor M1
Is controlled by the control means 100 to maintain the developer transport ratio Drate constant. (1) Drate = Vs × Dws where Vs (cm / sec) is the peripheral speed of the developer carrier 41 and Dws is the amount of developer per unit area on the developer carrier (mg / cm ² ). is there.

The developer transfer ratio Drate is obtained by an experiment. For example, the developer amount Dws at the time of the stable state
Is 35 mg / cm ² and the peripheral speed of the developer carrying member is 27 mg / cm ^2.
When an appropriate developing performance is obtained at cm / sec, the developer transport ratio Drate = 945 mg / cm · s
ec. The control means 100 calculates Drate = 945 m
The motor M1 is controlled so as to be g / cm · sec.

In the above control, the developer carrier 41
It is desirable that the amount of the upper developer be 70 mg / cm ² or less.

Next, the operation history of the image forming apparatus and the developer carrier 4 will be described with reference to the flowcharts of FIGS.
A description will be given of a control for correcting a change in the developer amount Dws due to the movement distance of 1 and always maintaining a constant developer transport ratio.

In the rotation speed control of the developer carrier 41 shown in FIG. 9, an operation / non-operation coefficient T representing the operation history of the developing device 4 is used. The operation / non-operation coefficient T is a coefficient for correcting the tendency as shown in FIG. 8 that the developer conveyance amount Dws is large in the morning and small when the image forming apparatus is stabilized after the continuous operation. Therefore, the operation / non-operation coefficient T is subtracted according to the operation time of the developing device 4 and added according to the non-operation time, as described below. The non-operation time includes a non-operation time of the developing device 4 when the power of the image forming apparatus is turned off and a non-operation time of the developing device 4 when the power of the image forming apparatus is turned on and in a standby state. It is. The operation / non-operation coefficient T is stored in a non-volatile memory (not shown), and the operation / non-operation coefficient is stored even when the power of the image forming apparatus is turned off.

In FIG. 9, when the power switch of the image forming apparatus is turned on, the time is measured by a clock (not shown) which is built in the image forming apparatus and measures the time when the power of the image forming apparatus is off. The operation / non-operation coefficient T is calculated from the non-operation time, and the calculated operation / non-operation coefficient T is loaded into the work memory of the control means 100 (F
1) Then, an interrupt timer for executing an interrupt routine (shown in FIG. 10) at one-second intervals is turned on (F).
2). As will be described later, the operation / non-operation coefficient T is a coefficient that increases when the developing device 4 is not operating and decreases when the developing device 4 is operating, and is calculated according to the following equation (2).

(2) T = T + t, where t is the time in seconds measured by the clock.

When the copy button is turned on (Yes in F3) in a standby state where the copy button is operated and turned on (No in F3), Vs, that is, the peripheral speed of the developer carrier 41 is set. (F4). The setting of the peripheral speed Vs will be described later.

The developer carrying member 41 rotates at the set peripheral speed Vs to execute copying (F5). During copying, Vs is always reset in response to a change in conditions in the image forming apparatus. That is, the peripheral speed Vs is set (F4) periodically (for example, every single copy) during the execution of the copy. When the copy is completed (Yes in F6), the process returns to the standby state.

FIG. 10 shows an interrupt routine executed at one-second intervals by a timer which is turned on at F2. This interrupt routine is one of the parameters for determining the peripheral speed Vs of the developer carrying member 41 of the developing device 4. This is a step of calculating the value of T, which is an activation / deactivation coefficient.

The operation / non-operation coefficient T is a predetermined value, for example, T0 = 7200 as an initial value T0 in a state where the developing device 4 is not operated, that is, in a state where a new developer is loaded and is not operated. Is set.

After the start of the interruption, first, at F10, it is checked whether the developing device 4 is operating. During the operation, the operation / non-operation coefficient T is subtracted by 4 (F1
1, T = T-4), and if it is paused, 1 is added (F12, T = T + 1). The calculations in F11 and F12 are examples of formulas based on experiments, and may be different formulas depending on the type of document device.

In this manner, the operation / non-operation coefficient T is reduced while the developing device 4 is operating, that is, while the developer carrier 41, the supply / conveyance means 45, and the stirring / conveyance means 46 are operating. In, a calculation for increasing the activation / deactivation coefficient T is performed. The activation / deactivation coefficient T has a lower limit of 0,
7200 is the upper limit.

FIG. 11 shows the process of setting the peripheral speed Vs of the developer carrier 41, that is, the contents of F4 in FIG.

In the step of setting Vs, first, F2
At 0 and F21, the operation / non-operation coefficient T and the moving distance coefficient L of the developer carrier 41 are loaded. The moving distance coefficient L is a moving distance of the developer carrying surface of the developer carrying body 41 in a unit of km (kilometer), and is a value obtained by integrating an initial state in which a new developer is supplied with zero. Memory 10
1 stores data shown in Table 1 representing the developer amount Dws corresponding to the activation / deactivation coefficient T and the moving distance coefficient L.

[0130]

[Table 1]

The data shown in Table 1 was obtained by a long run test in which the image forming apparatus was operated to form an image. The operation / non-operation coefficient T is obtained by a calculation process shown in FIG. 11, and the moving distance coefficient L is obtained from the operation time of the developing device 4. Therefore, the control means 10
0 refers to Table 1 stored in the memory 101 from the operation / non-operation coefficient T and the moving distance coefficient L obtained from FIG. 10 to determine the developer amount Dws, and the equation (1) Drate =
The peripheral speed Vs of the developer carrier 41 is obtained from Vs × Dws and set (F22, 23, 24).

In the above control, the control means 10
In the data processing at the time of creating the data of Table 1 and at the time of reading the data from Table 1, “0” performs an arithmetic processing of rounding down the decimal point when calculating the operation / non-operation count T.

FIG. 12 shows an example of such control. In FIG. 12, a curve C3 is an optimum condition, that is, an image of an appropriate density is formed, the developer transport ratio of the developer carrier 41, the supply amount to the developer carrier 41, and the developer carrier 41
7 is a curve connecting the peripheral speeds of the developer carrier 41 that maintains consistency with the amount collected from the developer carrier. Curve C4 shows the tendency in the morning, and curve C5 shows the tendency in the stable state.

<Fourth Embodiment> Control of toner supply to the developing device 4 is performed by the control unit 100 based on toner density information detected by a toner density sensor TS as a toner density detection unit. The toner density sensor TS detects the toner density by measuring the magnetic permeability of the developer.

It is known that the magnetic permeability of the developer changes due to factors other than the toner concentration. Since the magnetic permeability is a parameter reflecting the bulk density of the developer, the magnetic permeability changes according to the change in the bulk density of the developer. It is known to change.
This is mainly because when the developer is sufficiently stirred and its bulk density is low, and when the developer is left standing, the bulk density of the developer is high, even if the toner density does not change. This is a phenomenon that the output of the sensor TS changes.

The speed called the process speed of the image forming apparatus, that is, the rotation speed of the photosensitive member, the conveying speed of the recording material, and the conveying speed of the recording material of the fixing device maintain a fixed fixing property in the thick paper mode or the OHP mode. To be changed to
In the glossy image mode, in order to increase the gloss of the image, a change is made to reduce the recording material conveyance speed for the purpose of increasing the fixing degree. Along with such a change in the process speed, the rotation speed of the developer carrier 41, the supply / conveyance unit 45, and the stirring / conveyance unit 46 in the developing device 4 is changed. When the rotation speed is changed, that is, when the rotation speed of at least one of the developer carrier 41, the supply / conveyance unit 45, and the stirring / conveyance unit 46 is changed, the bulk density of the developer changes. , Toner concentration sensor TS
The output will change.

Table 2 shows the output of the toner density sensor TS when the peripheral speed of the developer carrier 41 is changed in three stages for the same developer. As is clear from Table 2, the output of the toner density sensor TS fluctuates even with the same developer, that is, a developer having no change in toner density.

As described above, the output of the toner density sensor TS for detecting the toner density by measuring the magnetic permeability varies in a complicated manner according to various parameters.

[0139]

[Table 2]

In the toner supply control, the toner density sensor T
The output of S is compared with a predetermined threshold value, and when the threshold value is exceeded, the toner replenishing means 51 is operated. However, according to the conventional control method, the change in Thus, a change in the output of the toner density sensor TS is predicted, and a threshold or a control voltage for controlling the output of the toner density sensor TS is corrected based on the predicted value. However, it has been found that accurate correction cannot be performed by such predictive control.

In the present embodiment, the thick paper mode, O
The correction value for the output of the toner density sensor TS when the process speed changes in the HP mode or the like is calculated based on the process speed to be changed, that is, for each recording material conveyance speed.
The toner replenishment control is set in advance by measurement and based on the correction value set at the time of image formation. Such a correction value for each process speed is measured and set when the image forming apparatus is adjusted after a new developer is supplied. The correction data may be set as correction data for a threshold, or may be set as a control voltage for controlling the output of the toner density sensor TS. Further, the correction data may be added to the output of the toner density sensor TS.

By such correction, proper correction is performed for all the fluctuation factors of the toner density sensor TS, and an image having a proper density can be formed.
The consistency between the transport amount, the supply amount, and the collection amount of the developer carrying member 41 is favorably maintained.

The control means 100 controls the toner supply means 51 based on the threshold value. That is, the toner concentration sensor TS
The output of the toner supply unit 5
1 is operated to supply toner. Therefore, the correction in the toner replenishment control is performed by changing the control voltage for changing the output level of the toner density sensor, changing the threshold value, or correcting the output value of the toner density sensor TS.

Table 3 shows an example of the control voltage correction, Table 4 shows an example of the threshold value correction, and Table 5 shows the correction of the output value of the toner density sensor TS. As is clear from Tables 3, 4 and 5, the toner density is maintained at a constant value by any of the corrections.

[0145]

[Table 3]

[0146]

[Table 4]

[0147]

[Table 5]

The above correction is performed by a two-component developer containing a polymerized toner having a small particle size and a carrier having a small particle size, that is, a magnetization amount of 3.8 × 1 in a magnetic field of 79 × 10 ³ A / m.
0 ^-5 8.8 a ^{× 10 -5 wb · m / kg} , and weight average particle diameter of 30~70μm carrier, weight average particle diameter of 3
It is particularly effective when a two-component developer having a non-magnetic toner polymerization in the range of from 8 to 8 μm is used.

[0149]

According to the first, second, third or fourteenth aspect of the present invention, the overrun when the developer carrier is stopped is eliminated, so that the accumulation of the developer in the collecting section is effectively prevented. Undesirable phenomena such as slip-through of the developer and packing are prevented, and a good image is always formed.
In particular, since the above-mentioned undesired phenomenon in the one-circulation system developing device is prevented, the advantages of the one-circulation system developing device can be fully utilized, and uniform and high-quality images can be formed. Become.

According to the fourth aspect of the present invention, it is possible to prevent the developer from being accumulated in the collecting section when the developing device is stopped by using appropriate driving and moving means for the developer carrying member and the collecting means. .

According to the fifth, seventh or fourteenth aspects of the present invention, the shortage of the developer supply amount to the developer carrier which tends to occur when the developing device is started is solved, and an image of a constant density is always formed. You.

According to the sixth aspect of the present invention, an appropriate driving means is used for the developer carrier and the supply means, and the insufficient supply of the developer is eliminated when the developing device is started, so that a good image is always obtained. Is formed.

According to the eighth aspect of the present invention, even in a developing device having a configuration in which the supply section is disposed below the recovery section, the insufficient supply of the developer is eliminated and a good image is formed.

According to the ninth aspect of the present invention, it is possible to use a toner having a small particle diameter, so that an image having excellent image quality such as resolution and reproducibility of image details can be formed. By using the toner having the particle size, the shortage of the developer which tends to occur can be solved, and a high-quality image can be stably formed.

According to the invention of claim 10, 13 or 14,
Since development is performed in accordance with the characteristics of the developer that changes in accordance with the operation of the developing device, a high-quality image having a constant image quality is always formed.

According to the eleventh or twelfth aspect of the present invention, a high-quality image having a uniform density is formed by using a one-circulation type developing device.

According to the invention of claim 15, 16 or 19,
As a result of the toner supply control using the magnetic permeability being performed under appropriate corrections for complicated fluctuation factors such as changes in the process speed and the operation history of the image forming apparatus, high-quality images without fluctuations in density can be obtained. It is formed stably.

According to the present invention, a high-quality image excellent in resolution, reproducibility of image details, and the like is formed.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a color copying machine according to an embodiment of the present invention.

FIG. 2 is a central sectional view of the developing device according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating a drive control system of the developing device.

FIG. 4 is a diagram showing a circulation system of a developer.

FIG. 5 is a diagram illustrating control timings of a developer carrier and a collecting unit according to the first embodiment of the present invention in comparison with a conventional one.

FIG. 6 is a diagram illustrating another example of the control timing of the developer carrier and the collecting unit according to the first embodiment of the present invention.

FIG. 7 is a diagram showing control timings of a developer carrier and a supply unit according to the first embodiment of the present invention in comparison with a conventional one.

FIG. 8 is a graph showing a change in a developer conveyance amount.

FIG. 9 is a flowchart of a rotation speed control of the developer carrier.

FIG. 10 is a flowchart of an interrupt routine.

FIG. 11 is a flowchart of a peripheral speed setting process of a developer carrier.

FIG. 12 is a graph showing control of a peripheral speed of a developer carrying member according to the third embodiment of the present invention.

[Explanation of symbols]

 1, 1Y, 1M, 1C, 1K Photoconductor 4, 4Y, 4M, 4C, 4K Developing device 41 Developer carrier 42 Magnetic field generating unit 43 Restricting unit 44 Supply unit 45 Supply / conveying unit 46 Stirring / conveying unit 47 Conveying roller 49 Collection unit 401 Supply unit 402 Stirring / conveying unit 403 Collection unit 100 Control unit 101 Memory TS Toner density sensor M1, M2 Motor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 9/087 G03G 15/08 507H 9/10 507E 15/00 303 21/00 372 21/14 15/08 507L 507X 9/08 384 101 (72) Inventor Kazutoshi Kobayashi 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation F-term (reference) 2H005 AA02 AB06 BA00 EA02 EA05 FA01 2H027 DA17 DA38 DC03 DD07 DE04 DE07 DE10 EA04 EA06 EC06 EC09 EC20 ED02 ED08 ED16 EE01 EE02 EE03 EE04 EE05 EE07 EE08 2H077 AA15 AA37 AB02 AB03 AB07 AB15 AB18 AC02 AC04 AD02 AD06 AD13 AD18 AD24 AD31 AD32 BA01 BA02 BA03 BA08 DA10 DA42 DA52 DB02 DB14 DB22 DB25 EA03

Claims (21)

[Claims] A developing unit that conveys a developer to a developing area and carries the developer in the developing area; a supply unit provided with a supply unit that supplies the developer to the developer supporting body; A recovery unit provided with a recovery unit for recovering the developer from the developer carrier, wherein the supply unit and the recovery unit are separated at least in an image area, and at least drive the developer carrier. A developing device in which a developing unit driving unit and a collecting unit driving unit that drives the collecting unit are separately provided, wherein the stop time of the developer carrier is the same as or before the stopping time of the collecting unit. A developing unit provided with a control unit for controlling the developing unit driving unit and the collecting unit driving unit. 2. The developing device according to claim 1, wherein the control unit controls the turning off of the developing unit driving unit before the turning off time of the collecting unit driving unit. 3. The control unit according to claim 1, wherein the control unit applies a brake to stop the developing unit driving unit.
Or the developing device according to claim 2. 4. The developing device according to claim 1, wherein the developing unit driving unit has a DC motor, and the collecting unit driving unit has a stepping motor. 5. A developer carrying member that transports a developer to a developing area and carries the developer in the developing area, a supply unit having a supply unit that supplies the developer to the developer carrying body, and the developer A recovery unit having a recovery unit for recovering the developer from the carrier, wherein the supply unit and the recovery unit are separated at least in an image area, and at least a developing unit driving the developer carrier Means and a supply unit drive unit for driving the supply unit, wherein the on-point of the development unit drive unit is simultaneous or before the on-point of the supply unit drive unit. Thus, the developing device is provided with control means for controlling the developing section driving means and the supply section driving means. 6. The developing device according to claim 5, wherein said developing unit driving means has a DC motor, and said supply unit driving means has a stepping motor. 7. The developing device according to claim 5, wherein a collecting unit driving unit that drives the collecting unit of the collecting unit is also used as the supply unit driving unit. 8. The developing device according to claim 1, wherein the supply unit is disposed below the collection unit. 9. The developing device according to claim 1, wherein development is performed using a polymerized toner. 10. A developer carrying member for transporting a developer to a developing region and carrying the developer in the developing region, a developing unit driving unit for driving the developer carrying member, and a developer carrying the developer on the developer carrying member. A supply unit having a supply unit that supplies the developer, a regulating unit that regulates an amount of the developer on the developer carrier, and a rotation speed of the development unit driving unit is changed to change the development area. And a control unit for controlling the transport ratio of the developer transported to the printer to be constant. 11. A method according to claim 11, further comprising a collecting section provided with a unit for collecting the developer from the developer carrying member, wherein the supply section and the collecting section are separated at least in an image area. Item 11. The developing device according to Item 10. 12. The developing device according to claim 11, wherein the supply unit is disposed below the recovery unit. 13. The developing device according to claim 10, wherein the regulating unit regulates the amount of the developer on the developer carrier to 70 mg / cm ² or less. 14. An image forming body, a latent image forming means for forming an electrostatic latent image on the image forming body, and a developing device according to any one of claims 1 to 13. Image forming device. 15. An image forming body, a latent image forming means for forming an electrostatic latent image on the image forming body, a two-component magnetic developer conveyed to a developing area by a developer carrier, and A developing device that develops the electrostatic latent image of the toner; a toner concentration detecting unit that detects a toner concentration of the two-component magnetic developer by measuring a magnetic permeability of the two-component magnetic developer in the developing device; An image forming apparatus comprising: a toner replenishing unit that replenishes the toner; and a control unit that controls the toner replenishing unit based on an output of the toner concentration detecting unit. An image forming apparatus for controlling the toner replenishing unit by changing a threshold value in control or changing an output value of the toner density detecting unit based on the obtained data. 16. A storage unit for storing the data obtained from an operation experiment of the developing device, wherein the storage unit detects the toner concentration for each recording material conveyance speed at the time of initial adjustment when a developer is supplied. The control threshold value of the control unit, the control voltage for changing the output value of the toner density detection unit, or the data of the correction value of the output of the toner density detection unit, which is obtained by calculating from the output value of the unit, is stored. The image forming apparatus according to claim 15, wherein: 17. The developing device, wherein the weight average particle diameter is 3 to
Magnetization in a non-magnetic toner of 8 μm and a magnetic field of 79 × 10 ³ A / m is 3.8 × 10 ^{−5 to} 8.8 × 10 ⁻⁵ wb ·
17. The image forming apparatus according to claim 15, wherein development is performed using a two-component developer containing a carrier having a weight average particle diameter of 30 to 70 [mu] m. 18. The image forming apparatus according to claim 15, wherein said non-magnetic toner is a polymerized toner. 19. An electrostatic latent image on an image forming body by controlling toner replenishing means for replenishing toner to a developing device based on an output of a toner density detecting means for detecting a toner density in a two-component magnetic developer. In the developing method of developing, based on data set for each moving speed of the image forming body, a threshold value for driving the toner replenishing unit is changed or an output of the toner density detecting unit is changed. A developing method comprising controlling a toner replenishing unit. 20. A non-magnetic magnetic powder having a weight average particle diameter of 3 to 8 μm.
Gnar and 79 × 10 ^ThreeThe amount of magnetization in a magnetic field of A / m is
3.8 × 10^-Five~ 8.8 × 10^-Fivewb · m / kg
Containing a carrier having a weight average particle size of 30 to 70 μm.
20. The method according to claim 19, wherein a two-component developer is used.
The developing method described in the above. 21. The developing method according to claim 19, wherein the non-magnetic toner is a polymerized toner.