JP2002031948A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome the problem of an unevenness in image density due to a gradient in the toner concentration in the direction of a rotating shaft of a screw agitating developer and feeding the developer to a developing roll and moreover to solve any developing failure due to any failure in carrying the developer in an edge part of an image that is generated when the unevenness in the image density is solved. SOLUTION: In the device, a feeding part of the developer and a recovery part of the developer are separated within a range of a developing width and the speed of revolution of the developing roll is set so that the quantity of the developer that is carried to the developing roll does not exceed the quantity of the developer that is fed to the developing roll.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image by an electrophotographic method, and more particularly to an improvement of a developing device for developing an electrostatic latent image.

[0002]

2. Description of the Related Art (1) One of the conditions to be satisfied by a developing device of an image forming apparatus for forming an image by an electrophotographic method is as follows.
That is, uniform development is performed over the entire image. The basic configuration of a developing device that performs development using a two-component developer is as follows:
A developing roller for transporting the developer to the developing area, a supply and transport unit for supplying the developer to the developing roller, and a stirring and transporting unit for uniformly stirring and transporting the developer in the developing device, that is, the developer including the toner and the carrier. This is a recovery unit that returns the developer on the conveying unit and the developing roller to the stirring / conveying unit.

In many cases, the supplying / transporting means and the collecting means are also used, and a rotating screw is often used as the supplying / transporting / collecting means. In the process, the developer is uniformly supplied to the developing roller in the axial direction. The toner is added to the developer conveyed by the agitating / transporting unit, and the developer having the added toner and having a high toner concentration is supplied from the agitating / conveying unit to the supply / conveying / collecting unit.

FIG. 1 schematically shows the structure of the conventional developing device. The developer is transported by a supply / transport / collection unit SK composed of a screw along the rotation axis of the supply / transport / collection unit SK as indicated by an arrow D1. In the course of transport, the toner is supplied to the developing roller RR as indicated by an arrow D2. The developer that has passed through the developing area is a developing roller RR.
At the release pole, and is returned to the supply / transport / collection means SK as shown by the arrow D3. Conveyed. In the stirring / transporting means KH, as shown by an arrow D4, the stirring / transporting means KH is transported with stirring in the rotation axis direction of the stirring / transporting means KH.
From the supply / transport / collection means SK. As shown by the arrow T, the toner is added to the developer at the upstream end of the stirring / transporting means KH.

[0005] By the circulation of the developer as described above, the transport and stirring of the developer are efficiently performed. (2) A basic configuration of a developing device that performs development using a developer includes a developing roller that transports the developer to a developing area, a supply / transport unit that supplies the developer to the developing roller, and a developer in the developing device. And a collecting means for returning the developer to the stirring and conveying means on the developing roller.

As the collecting means, a stripping member whose leading end contacts the developing roller or a stripping roller provided in the vicinity of the developing roller is used. The peeling roller is widely used as a collecting means having few defects such as abrasion of the surface of the developing roller.

The peeling roller has a function of peeling the developer from the developing roller by magnetic force and rotation, and is driven and rotated by a common driving means with the developing roller.

[0008]

(1) The structure of the developing device described above is such that the space for transport and stirring is reduced as much as possible for the purpose of making the developing device compact. The configuration has the following problem in making the device compact.

In the flow of the developer indicated by arrows D1 to D4 in FIG. 1, the black arrow indicates the flow of the developer having a high toner concentration, and the white arrow indicates the flow of the developer having a low toner concentration.
The arrow of the intermediate density indicates the flow of the developer having the intermediate toner density.

As shown, supply / transport / collection means SK
In the upstream part, the toner concentration of the developer is sufficiently high, but as a result of the developer having a low toner concentration being added from the developing roller RR to the supply / transport / collection means SK, the toner concentration becomes lower toward the downstream. As a result, in the flow of the developer indicated by the arrow D2, the toner concentration decreases downstream of the supply / transport / collection unit SK. That is, the density in the developing width direction becomes non-uniform.

Accordingly, the density of the image developed at the portion of the developing roller to which the developer having a low toner concentration is supplied is reduced.

The gradient of the toner concentration as described above devises the mutual positional relationship among the developing roller RR, the supply / transport / collection means SK, and the stirring / transport means KH, the shape of each component, and the like. However, this cannot be corrected when the developing device is made more compact, and there is a problem that the developability becomes non-uniform in the developing width direction.

In Japanese Patent Application Laid-Open No. 62-28871, as a measure to prevent the above-mentioned nonuniform density, the
There has been proposed a developing device in which the transporting means and the collecting means are separately provided without being shared, and the developer recovered by the collecting means by separating the two is returned to the supply / transporting means outside the developing width. ing.

On the other hand, the gradation and the maximum density of an image are adjusted by controlling the number of revolutions of the developing roller. When the number of revolutions of the developing roller is changed, the developer supplied to the developing roller is adjusted. If the balance between the amount of the developer and the amount of the developer conveyed on the developing roller is not set properly, the amount of the developer on the developing roller may be insufficient, and the image density may be rapidly reduced locally. is there. In the developing device disclosed in Japanese Patent Application Laid-Open No. 62-28871, it is possible to avoid unevenness in image density due to unevenness in toner density in the developing width direction. It may drop sharply.

A first object of the present invention is to solve the above-mentioned problems in the conventional developing device and to provide an image forming apparatus provided with a developing device having a uniform developing property. (2) For the purpose of controlling the developing property of the developing device, that is, controlling the image density, the number of rotations of the developing roller is changed. By increasing the rotation speed of the developing roller,
The amount of developer supplied to the developing area increases, and a high-density image is formed.

In the conventional apparatus in which the peeling roller of the collecting means is driven by a common driving means with the developing roller, when the number of rotations of the developing roller is changed for controlling the image density or the like, unevenness of the image density or the like is reduced. It has been found that image quality may deteriorate.

FIG. 7 shows this phenomenon according to an embodiment of the present invention.
This will be described with reference to FIG. The developer DV on the developing roller 31 is
The arrangement of the magnetic poles of the magnet M1 included in the developing roller 31 and the arrangement of the magnetic poles of the magnet M2 included in the stripping roller 37 transfer to the stripping roller 37, and the developer DV on the stripping roller 37 It is peeled off by the stripping member 38 and transported by the collection / transport screw 39.

When the number of rotations of the stripping roller 37 is reduced, the stripping member 38 is not completely stripped, and the developer DV slips between the stripping roller 37 and the stripping member 38. It is easy to occur. As a result, the developer DV on the peeling roller 37 may make a round on the peeling roller 37 and adhere to the developing roller 31 again. The developer DV that has re-adhered to the developing roller 31 has a low toner concentration. When such a developer DV is supplied to the developing area, development unevenness occurs.

A second object of the present invention is to provide an image forming apparatus capable of forming a high-quality image by preventing the above-mentioned deterioration in image quality caused when a peeling roller is used as the collecting means. With the goal. (3) In a developing device using a peeling roller as a collecting means, the developing roller is conveyed by the developing roller according to environmental conditions, that is, changes in temperature or humidity, or the degree of deterioration of the developer and the surface condition of the developing roller. There is a problem that the amount of developer and the peeling performance of the peeling roller change to affect the image quality.

The third and fourth aspects of the present invention prevent such a change in image quality as described above due to a change in environmental conditions, a degree of deterioration of a developer, or a degree of deterioration of a surface of a developing roller or the like. An object is to provide an image forming apparatus capable of forming an image. (4) When the peeling roller is used as the collecting means and the peeling roller is driven independently of the developing roller, the drive control of the developing roller and the peeling roller is performed separately. If the cleaning is not performed correctly, the transportability of the developer on the developing roller may not be constant, which may affect the image quality.

According to a fifth aspect of the present invention, there is provided an image forming apparatus which can solve the above-described problem when the peeling roller of the collecting means is driven independently of the developing roller, and can always form a high quality image. The purpose is to provide.

[0022]

The above-mentioned object of the present invention is achieved by the following inventions.

1. A developing roller comprising a developing unit, a supplying unit and a collecting unit separated from the supplying unit at least within a range of a developing width, including a plurality of fixed magnets, and transporting a developer to a developing area in the developing unit. A regulating unit provided in the developing unit, for regulating an amount of the developer conveyed to the developing region, a supply / conveyance screw for conveying the developer in the rotation axis direction while supplying the developer to the developing unit side in the supply unit An image forming apparatus comprising: a supply unit that supplies a developer to the developing unit; and a developing device that is provided in the collection unit and that includes a collection unit that returns the developer on the developing roller to the supply unit. , The diameter of the developing roller is A [m
m], the amount of the developer regulated by the regulation means and conveyed on the developing roller is D [mg / cm ² ], the conveyance width of the developer is L [mm], and the diameter of the supply / conveyance screw is B [mm], the screw shaft diameter of the supply / conveyance screw is C [mm], the rotation speed of the supply / conveyance screw is R1 [rpm], the pitch of the supply / conveyance screw is P [mm], An image forming apparatus wherein the developing roller rotates at a rotation speed Rs [rpm] satisfying the following conditions, where the bulk density is K [g / cm ³ ] and the developer supply rate is α. ≦ {25 × α × K × (B ² −C ² ) × P × R1} /
(D × A × L).

2. 2. The image forming apparatus according to claim 1, wherein the image density is controlled by controlling at least one of the voltage of the electrostatic latent image and the developing bias without changing the rotation speed of the developing roller.

3. 2. The image forming apparatus according to claim 1, wherein the number of rotations of the developing roller is variable.

4. 2. The image forming apparatus according to claim 1, wherein the number of rotations of the developing roller is variable, and the image density is controlled by controlling at least one of a voltage of an electrostatic latent image and a developing bias.

5. A developing unit, a stirring unit, a supply unit separated from the stirring unit at least within a range of the developing width, and a collecting unit separated from the supplying unit and at least within a range of the developing width, including a plurality of fixed magnets. A developing roller that conveys the developer to a developing region in the developing unit; a regulating unit that is provided in the developing unit and regulates an amount of the developer conveyed to the developing region; and agitates the developer in the stirring unit. A stirring / conveying screw that conveys the developer in the direction of the rotating shaft, and a supply / conveying screw that conveys the developer in the direction of the rotating shaft while stirring and supplies the developing unit to the developing unit in the supply unit; An image forming apparatus including a developing device having a collecting unit that collects the developer from above the developing roller and returns the developer to the downstream side of the flow of the developer from outside the range of the developing width on the downstream side in the supply unit. To The collection means has a collection and conveyance screw that conveys the developer collected from the developing roller in the direction of the rotation axis, and the collection and conveyance screw allows the collected developer to be developed in the stirring section. By returning to the upstream part of the flow of the agent,
Forming a circulating transport system for the developer returning from the stirring section to the stirring section via the supply section, the developing section and the recovery section, and lowering the stirring section and the supply section with respect to the developing section. And providing the collecting sections above, respectively.
The diameter of the developing roller is A [mm], the amount of developer transported on the developing roller regulated by the regulating means is D [mg / cm ² ], and the transport width of the developer is L [m
m], the diameter of the supply / transport screw is B [mm], and the screw shaft diameter of the supply / transport screw is C [m
m], the number of rotations of the supply / conveyance screw is R1 [rp
m], and the pitch of the supply / transport screw is P [m
m], when the bulk density of the developer is K [g / cm ³ ] and the developer supply rate is α, the developing roller rotates at a rotation speed Rs [rpm] satisfying the following condition. Rs ≦ {25 × α × K × (B ² −C ² ) × P × R1} /
(D × A × L).

6. 6. The image forming apparatus according to claim 5, wherein the collection unit includes a peeling roller that peels off the developer on the developing roller.

7. 7. The image forming apparatus as described in 5 or 6, wherein a water wheel for conveying the developer conveyed by the supply / conveyance screw to the developing roller is provided.

8. A toner replenishing section for replenishing toner is provided in the upstream portion of the stirring section.
8. The image forming apparatus according to claim 7.

9. The toner replenishment position in the upstream portion is located downstream of the flow of the developer from the position where the developer is returned from the collection portion, and the toner concentration of the developer is between the return position and the toner replenishment position. 9. The image forming apparatus according to claim 5, further comprising: a toner density detecting unit configured to detect the toner density.

10. 10. The image density is controlled by controlling at least one of the voltage of the electrostatic latent image and the developing bias without changing the rotation speed of the developing roller. Image forming apparatus.

11. The image forming apparatus according to any one of claims 5 to 9, wherein the number of rotations of the developing roller is variable.

12. The method according to any one of the above items 5 to 9, wherein the number of rotations of the developing roller is variable, and the image density is controlled by controlling at least one of the voltage of the electrostatic latent image and the developing bias. The image forming apparatus as described in the above.

13. The image forming apparatus according to any one of 1 to 12, wherein the supply rate α is 0.35 or more.

14. A developing roller that conveys the developer to the developing region by rotation, a supply unit that supplies the developer to the developing roller by rotation, a regulating unit that regulates the amount of the developer conveyed to the developing region, and In an image forming apparatus including a developing device having a collecting unit that collects a developer, the collecting unit includes a plurality of fixed magnets, and has a peeling roller that peels the developer from the developing roller, The peel roller is driven independently of the developing roller, and the rotational speed of the peel roller is constant when the rotational speed of the developing roller is changed to change the developing property of the developing device. An image forming apparatus comprising:

15. The diameter of the developing roller is A [mm],
When the diameter of the stripping roller is E [mm] and the maximum value of the number of rotations of the developing roller is RsMax, the number of rotations Rr of the stripping roller is Rr ≧ RsMax (A / E).
15. The image forming apparatus according to the above 14, wherein:

16. A developing roller that conveys the developer to the developing region by rotation, a supply unit that supplies the developer to the developing roller by rotation, a regulating unit that regulates the amount of the developer conveyed to the developing region, and In an image forming apparatus including a developing device having a collecting unit that collects a developer, the collecting unit includes a plurality of fixed magnets, and has a peeling roller that peels the developer from the developing roller, An image characterized in that the stripping roller and the supply unit are driven by a common driving unit, and the developing roller is driven by a driving unit different from the driving unit of the stripping roller and the supply unit. Forming equipment.

17. The diameter of the developing roller is A [mm],
When the diameter of the stripping roller is E [mm] and the maximum value of the number of rotations of the developing roller is RsMax, the number of rotations Rr of the stripping roller is Rr ≧ RsMax (A / E).
17. The image forming apparatus as described in 16 above, wherein

18. A developing roller that conveys the developer to the developing region by rotation, a supply unit that supplies the developer to the developing roller by rotation, a regulating unit that regulates the amount of the developer conveyed to the developing region, and In an image forming apparatus including a developing device having a collecting unit that collects a developer, the collecting unit includes a plurality of fixed magnets, and has a peeling roller that peels the developer from the developing roller, The peeling roller is driven independently of the developing roller, and has an environment detecting means and a control means. The controlling means controls the number of revolutions of the peeling roller based on detection information of the environment detecting means. An image forming apparatus.

19. A developing roller that conveys the developer to the developing region by rotation, a supply unit that supplies the developer to the developing roller by rotation, a regulating unit that regulates the amount of the developer conveyed to the developing region, and In an image forming apparatus including a developing device having a collecting unit for collecting a developer, the collecting unit includes a plurality of fixed magnets, and has a peeling roller that peels off the developer from the developing roller. A first integrating means for driving the peeling roller independently of the developing roller and integrating a sliding distance of the surface of the developing roller, and a developing means for the developing roller based on an integrated result of the first integrating means. An image forming apparatus comprising control means for controlling the number of rotations.

20. A developing roller that conveys the developer to the developing region by rotation, a supply unit that supplies the developer to the developing roller by rotation, a regulating unit that regulates the amount of the developer conveyed to the developing region, and In an image forming apparatus including a developing device having a collecting unit that collects a developer, the collecting unit includes a peeling roller that peels off the developer from the developing roller, and the peeling roller is independent of the developing roller. And a control means for controlling the number of revolutions of the peeling roller based on the result of the integration by the second integrating means. An image forming apparatus comprising:

21. The diameter of the developing roller is A [mm],
When the diameter of the stripping roller is E [mm] and the maximum value of the number of rotations of the developing roller is RsMax, the number of rotations Rr of the stripping roller is Rr ≧ RsMax (A / E).
21. The image forming apparatus according to any one of the above items 18 to 20, wherein

22. A developing roller that conveys the developer to the developing region by rotation, a supply unit that supplies the developer to the developing roller by rotation, a regulating unit that regulates the amount of the developer conveyed to the developing region, and In an image forming apparatus including a developing device having a collecting unit for collecting a developer, the collecting unit is driven independently of the developing roller, and has a peeling roller that peels off the developer on the developing roller. An image forming apparatus, wherein the peeling roller is driven to rotate during a time that includes a rotation time of the developing roller.

23. 23. The image forming apparatus according to claim 22, wherein the rotation of the peeling roller when the operation of the developing device is started is performed earlier than the rotation of the developing roller.

24. 24. The image forming apparatus as set forth in 22 or 23, wherein a stop of the peeling roller when the developing device is stopped is delayed from a stop of the developing roller.

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) First Embodiment FIG. 2 shows an image forming apparatus according to a first embodiment of the present invention.

FIG. 3 is a diagram showing the flow of the developer in the embodiment shown in FIG. 1, and FIG. 4 is a diagram showing the distribution of the amount of the developer in the developer supply section.

In FIG. 2, reference numeral 1 denotes a photosensitive member. As the photoreceptor, an organic photoreceptor having a photosensitive layer in which an organic photoconductor is dispersed in a resin is preferable from the viewpoint of environmental friendliness and cost.

Reference numeral 2 denotes a charging device that charges the photosensitive member 1 and forms a uniform potential on the photosensitive member 1. As a charging device,
It is preferable to use a scorotron charger having a control grid and a discharge electrode or a contact charger using a roller to which a transfer voltage is applied. In the present embodiment, the photoconductor 1 is negatively charged.

Reference numeral 3 denotes an exposure device for exposing the photosensitive member 1 in accordance with image data. As the exposure apparatus, a scanning exposure apparatus using a laser diode as a light source and having a scanning optical system composed of polygons, lenses and mirrors, and a scanning optical apparatus having a light emitting diode array and an image forming optical fiber are preferable. The exposure device 3 performs dot exposure on the photoconductor 1 according to the image data.

Reference numeral 4 denotes a developing device, which contains a two-component developer, transports the developer to a developing area DE by a developing roller 11 to develop an electrostatic latent image on the photoconductor 1, and Form a toner image. A DC developing bias having the same polarity as the charging polarity of the charging device 2 or a developing bias in which an AC voltage is superimposed on a DC voltage is applied to the developing roller 11.
Is performed to cause the toner to adhere to the exposed portion. Note that, as the developing device 4, a developing device that performs regular development in which toner is adhered to an unexposed portion of the photoconductor 1 can be used.

Reference numeral 5 denotes a transfer device including a corona charger. The transfer device 5 charges the recording paper P with a polarity opposite to that of the toner on the photoconductor 1, and transfers the toner image to the recording paper P.

Reference numeral 6 denotes a separation device including a corona charger, which performs AC corona charging on the recording paper P, removes electricity from the recording paper P, and separates the recording paper P from the photoreceptor 1.

A fixing device 7 fixes a toner image on the recording paper P by a heating roller 71 having a built-in heat source such as a halogen lamp and a pressure roller 72 pressed against the heating roller 71.

Reference numeral 8 denotes a cleaning device, which removes untransferred toner adhered to the photoreceptor 1 after transfer and particles separated from the recording paper P.

In accordance with the rotation of the photosensitive member 1 in the direction indicated by the arrow X1, an electrostatic latent image is formed on the photosensitive member 1 by charging by the charging device 2 and exposure by the exposure device 3. The formed electrostatic latent image is developed by the developing device 4 to form a toner image on the photoconductor 1. The formed toner image is transferred to the recording paper P by the transfer device 5. After the recording paper P to which the toner image has been transferred is separated from the photoreceptor 1 by the separation device 6,
The fixing process is performed by the fixing device 7. The photoreceptor 1 after the transfer is cleaned by the cleaning device 8 to be in a state where a next image can be formed.

As shown in FIGS. 2 and 3, in the outer frame 10 of the developing device 4, the photosensitive member 1 is disposed so as to face the photosensitive member 1.
A developing area DE is formed at a position opposite to the arrow X2.
, A developing roller 11 for transporting the developer DV to the developing area DE by rotating in the direction of FIG. And a regulating member 1 as a regulating means for regulating the amount of the developer DV conveyed on the developing roller 11.
3. A supply / conveyance screw 14 that constitutes a supply unit and supplies the developer DV to the developing roller 11 while stirring the developer DV, a stripping member 15 that strips the developer DV from the developing roller 11, and a stripped member 15 A collection / conveyance screw 16 for stirring and conveying while collecting the developer DV is provided.

The inside of the developing device 4 is divided into a developing section CH1 provided with a developing roller 11, a supply section CH2 separated by a partition plate 17, and a collecting section CH3.

The magnet M forms a developing magnetic pole with the magnetic pole S1, and facilitates stripping of the developer between the magnetic pole N3 and the magnetic pole N2. Arrows W1, W2, W in FIG.
3. A flow of the developer as shown by W4 is formed.

The toner is supplied to the supply unit CH2 as indicated by the arrow T.
Is supplied at the most downstream portion of the developer and mixed into the developer.
The supply portion CH2 and the recovery portion CH3 are separated by a partition plate 17 into a developing width H (the maximum width of the image in the rotation axis direction of the developing roller 11,
Hereinafter the same). As a result, within the range of the developing width H, the developer DV moves from the collecting section CH3 to the supplying section C.
It does not move to H2. The developer DV is supplied to the supply section CH.
From the position 2 to the collecting portion CH3, the portion outside the range of the developing width H, that is, the portion of the opening 17b moves as indicated by an arrow W2. Then, the developer DV is supplied from the recovery unit CH3 to the supply unit C.
At the opening 17a provided outside the range of the development width H to H2, the opening 17a moves as indicated by an arrow W4.

In the image formation, the developing roller 11 rotates as shown by the arrow X2 with respect to the photosensitive member 1 which rotates as shown by the arrow X1, and the electrostatic latent image on the photosensitive member 1 becomes the developer D.
The toner image is formed on the photoreceptor 1 by being developed by V. The developer DV is supplied with an arrow W by the supply / transport screw 14.
As shown by 1, in the process of being conveyed in the screw rotation axis direction, the toner is uniformly supplied to the developing roller 11 within the range of the developing width H. The developing width H is substantially equal to the length of the developing roller 11. In the development area DE, the developer DV whose toner concentration has been reduced due to the consumption of the toner is peeled off from the developing roller 11 by the peeling member 15, and as shown by an arrow W <b> 3, After being conveyed along the opening 17, an opening 17 provided at an end position outside the developing width H of the partition wall 17 is provided.
As shown by the arrow W4 from a, the process returns to the supply unit CH2. The developer DV after the development moves from the opening 17b provided in the partition wall 17 to the collecting part CH3 as shown by an arrow W2. As shown by the arrow T, the toner is supplied from the opening 10a, and the amount consumed in the development is replenished. The replenished toner is uniformly mixed with the developer in the conveyance process indicated by W3 by the collection / conveyance screw 16.

In the developing device 4 which performs development by circulating and transporting the developer DV as described above, the developer DV that has been peeled off from the developing roller 11 and collected, that is, the developer DV whose toner concentration has decreased, has a developing width of At the end position in the direction
It is returned to the supply / transport screw 14. Then, the toner is similarly added to the developer DV at the end position in the developing width direction. In such a circulation system of the developer DV, the toner concentration of the developer DV conveyed by the supply / conveyance screw 14 is basically in the developing width direction (the same applies to the direction of the rotation axis of the developing roller 11 and below). The toner density of the developer DV supplied to the developing roller 11 is uniform in the developing width direction without any gradient of the toner density in the developing width direction, and uniform developing performance is secured.

On the other hand, in the developer circulation system, the developer DV moves from the supply / transport screw 14 to the developing roller 11 in the process of flowing from the upstream side to the downstream side of the end position in the developing width direction. The amount of the developer transported by the transport screw 14 decreases as going downstream.

FIG. 4 shows the distribution of the developer amount in the supply section CH2 where the supply screw 14 is disposed. As shown, the upstream portion CH2a of the supply portion CH2 is connected to the downstream portion CH2.
A developer distribution DVM is formed which gradually decreases towards 2c. In the downstream portion CH2c, as long as an appropriate amount of the developer DV is present, the normal transport of the developer DV is performed on the developing roller 11, and an image having a uniform density is formed. If the amount of the DV is insufficient or the developer runs out, normal conveyance of the developer DV on the developing roller 11 is not performed, and a defective development occurs at an end position in the developing width direction.

FIG. 5 shows the amount of the developer on the developing roller 11 when the number of revolutions of the developing roller 11 is changed [mg / cm ² ].
Shows the results of the measurement. As shown in FIG. 5, when the rotation speed of the developing roller 11 is increased, the supply portion C of the developing portion CH1 is changed.
In the portion CH1a and the central portion CH1b corresponding to the upstream portion CH2a of H2, even when the rotational speed of the developing roller 11 is changed, the values are almost constant without changing as shown by the curves RP and CP. Downstream section CH of supply section CH2
In the portion CH1c corresponding to 2c, the amount of developer sharply decreases as shown by the curve FP. That is, it was observed that the image density at the position corresponding to the end position CH1c in FIG. This is the developing section CH1
Is caused by the shortage or absence of the developer DV in the downstream corresponding portion CH1c.

The inventor of the present invention has searched for conditions for eliminating such a phenomenon of developer conveyance failure at an end position in the developing width direction, and as a result, the rotational speed Rs of the developing roller 11 satisfies the following equation (1). By setting the value to a value, it was possible to prevent the above-described developer conveyance failure.

Equation (1) Rs ≦ {25 × α × K × (B ² −C ² ) × P × R1} /
(D × A × L) In the above formula, A [mm] is the diameter of the developing roller 11 and D
[Mg / cm ² ] is the amount of developer transported on the developing roller 11 regulated by the regulating plate 13, L [mm] is the developer transport width, and B [mm] is the supply / transport screw 14
, C [mm] is the screw shaft diameter of the supply / transport screw 14, and R1 [rpm] is the supply / transport screw 14
, P [mm] represents the pitch of the supply / conveyance screw 14, K [g / cm ³ ] represents the bulk density of the developer, and α represents the developer supply rate.

In the above equation, the supply rate α is the supply / conveyance at the maximum number of rotations at which the developer conveyance failure does not occur on the development roller 11 as shown in FIG. Developing roller 11 relative to the amount of developer DV transported by screw 14 per unit time
The above is the ratio of the amount of the developer DV supplied to be stably conveyed. FIG. 5 shows a change in the amount of the developer DV conveyed on the developing roller 11 when the rotation speed of the developing roller 11 is increased. As is apparent from FIG. 5, the transported developer DV changes with the change in the number of rotations of the developing roller 11.
Although there is almost no change in the amount per unit area, the transport amount sharply decreases as indicated by the curve FP in the portion CH1c of the developing unit CH1 corresponding to the downstream portion of the supply unit CH2 when the rotation speed is increased. . This is caused by the poor conveyance of the developer, and the supply rate α is obtained by substituting the maximum number of rotations in a range that does not cause the poor conveyance of the developer downstream of the supply unit CH2 into the number of rotations Rs of the developing roller 11. Can be obtained by

The developer transport width L is the width of the developer DV transported by the developing roller 11, and is substantially equal to the length of the magnet M.

For example, A = 40 mm, L = 300 mm,
Rs = 200 rpm, B = 24 mm, C = 8 mm, P =
35 mm, R1 = 400 rpm, K = 1.9 g / c
When the developing device is operated under the device condition of m ³ ,
The amount D of the developer DV conveyed on the developing roller 11 is 10
In the case of 0 mg / cm ² , Rs = 200 rpm was the upper limit value at which developer conveyance failure did not occur. When these numerical values are substituted into the above equation, the supply rate α of the developing device under the above developing conditions becomes α = 0.70.

In this example, the developing roller 11 is set to 200 rpm
By rotating at a number of rotations equal to or less than m, it is possible to form an image with a uniform density without a developer conveyance failure as shown by a curve FP in FIG. Also, the supply rate α =
In the developing device of 0.70, if the amount D of the developer DV conveyed by the developing roller 11 is 50 mg / cm ² , the developing roller 11 is rotated at 397 rpm or less,
An image having a uniform image density can be formed without causing a conveyance failure of the developer on the developing roller 11. (2) Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. 6, reference numeral 21 denotes a photoconductor, 22 denotes a charging device, 23 denotes an exposure device, 24 denotes a developing device, 25 denotes a transfer device, 26 denotes a separation device, 27 denotes a fixing device, and 28 denotes a cleaning device.

Although the detailed description of the components 21 to 28 is the same as that of FIG. 2 and omitted, 21 in FIG. 6 corresponds to 1 in FIG. 2, and 22 in FIG.
Is equivalent to Similarly, 23 to 28 in FIG. 6 correspond to 3 to 8 in FIG. 29 is an environment sensor for detecting temperature and relative humidity, and TS is a toner density sensor.

FIG. 7 shows details of the developing device 24 according to the second embodiment of the present invention. Embodiment 2 of the present invention shown in FIG. 7 includes a system for supplying a developer having a specified toner concentration to a developing roller by supplying a developer to a circulating transport system of the developer,
This is completely separated from a system for recovering a developer in which the toner is consumed and the toner concentration is reduced by the development.

First, an outline of the flow of the developer in the second embodiment will be described with reference to FIG. In the second embodiment,
The flow of the developer from the supply / conveyance screw 35 to the collection / conveyance screw 39 via the developing roller 31 and further from the development roller 31 to the collection / conveyance screw 39 is performed within the range of the development width H1. The flow of the developer returning to the stirring / transport screw 34 via the supply / transport roller 35 and the flow of the developer between the stirring / transport screw 34 and the supply / transport screw 35 are performed in a range including outside the development width H1. . The transport of the developer outside the range of the development width H1 is performed, for example, through an opening provided at an end of the partition plate as shown in FIG. Also in FIG. 8, the flow of the developer having a high toner concentration is indicated by a black arrow, and the flow of the developer having a low toner concentration is indicated by a white arrow. The toner is replenished at the position indicated by T and mixes with the developer. In the circulation process between the supply section CH2 and the stirring section CH4 indicated by arrows V1 and V2, the replenished toner is uniformly mixed into the developer, and becomes a developer having a high toner concentration.

The developer having the flow indicated by V3 and V4 from the supply / transport screw 35 to the developing roller 31 via the water wheel 36 has a high toner concentration. In the developing roller 31, as a result of the toner being consumed by the developing action, the toner density decreases. The developer having a low toner concentration in the flow indicated by V5 and V6 is collected by the collection and conveyance screw 39, and returns to the stirring and conveyance screw 34 via the supply and conveyance screw 35. As shown by the arrow T, as a result of toner supply,
The toner concentration of the developer is high enough for development.

In FIG. 7, a developing roller 31, a magnet M1, a regulating member 33, a stirring /
Transport screw 34, supply / transport screw 35, water wheel 36, stripping roller 37, magnet M2, stripping member 3
8 and a collection / transport screw 39 are provided. Water wheel 3
Reference numeral 6 denotes a conveying member having a length including the developing width and having four blades parallel to the rotation axis direction, and having a conveyance function in the rotation direction, but having a conveyance function in the rotation axis direction. Do not have.

The peripheral surface of the developing roller 31 moves in the same direction X2 as the photosensitive member 21, and supplies the developer DV to the developing area DE to perform development. The stirring / conveying screw 34 conveys the developer DV in the rotation axis direction while stirring the developer.

The inside of the developing device 24 includes an outer frame 30 and a partition wall 40.
41, a developing unit CH1, a supply unit CH2, and a collecting unit CH
3 and a stirring section CH4.

The toner is replenished to the developer in the width of the developing roller 31, that is, in a range H3 outside the range of the developing width H1. The developer replenished with the toner is conveyed as indicated by V1 while being stirred by the stirring / conveying screw. The stirring section CH4 and the supply section CH2 are substantially separated at least within the range of the developing width H1, and the developer conveyed through the stirring section CH4 is outside the range of the developing width H1 at the downstream portion of the stirring section CH4 at an arrow V1 at H2. Is transported to the supply unit CH2. The developer is uniformly moved in the direction of the developing width within the range of the developing width H1 as shown by the arrow V3 while moving in the direction of its rotation axis as shown by the arrow V2 by the supply / conveying screw 35 in the supply section CH2. Move to 36. The water wheel 36 does not have a transport function in the rotation axis direction, and transports the developer from the supply / transport screw 35 to the developing roller 31 as shown by an arrow V4. The supply / transport screw 35 and the water wheel 36 Constitute. Developing roller 3
The developer, which has been conveyed by 1 and has passed through the developing area, has its toner concentration reduced due to the developing action, is peeled off from the developing roller 31 as shown by an arrow V5, passes through a peeling roller 37, and as shown by an arrow V6. Then, it moves to the collection / conveyance screw 39. Stripping roller 37 and stripping member 3
The collection screw 8 and the collection / transport screw 39 constitute collection means.

The developer is further conveyed by the collection / conveyance screw 39 as indicated by an arrow V7, and joins the developer flow V1 in the stirring section CH4 via the supply section CH2 at H3 outside the development width range.

The developer is conveyed in the circulation system as described above, but a part of the developer circulates between the supply section CH2 and the stirring section CH4 as shown by arrows V1, V2, V9 and V10. The developer from the recovery section CH3 is supplied to the supply section C in the circulation system.
It merges from the downstream part of H2 at the position of the upstream part of the stirring part CH4, and returns to the stirring part CH4. Then, the toner is similarly added to the developer at a position from a downstream portion of the supply portion CH2 to an upstream portion of the stirring portion CH4.

It is desirable to detect the toner concentration between the downstream portion of the supply portion CH2 and the upstream portion of the stirring portion CH4 and from the developer upstream of the toner replenishment position. The toner concentration is detected by the toner concentration sensor TS in the flow V9 of the collected developer DV between the merging position of the developer DV from the supply / transport portion CH2 and the collecting portion CH3.

The collected developer DV is supplied to the supply section CH2.
May be directly returned to the stirring section CH4 without passing through. In this case, the detection of the toner concentration is performed downstream of the merging position of the collected developer in the stirring section CH4, and the toner supply is performed further downstream of the toner concentration detection.

In the second embodiment, the developing roller 3
1 indicates that the amount of the developer conveyed thereon is the developing roller 31
Is less than or equal to the amount of developer supplied to
It is driven to rotate at a rotation speed satisfying the expression (1).

In the formula (1), A [mm] is the diameter of the developing roller 31, D [mg / cm ² ] is the transport amount of the developer conveyed on the developing roller 31 regulated by the regulating member 33, L [Mm] is the developer conveyance width, B [mm] is the supply
The diameter of the transfer screw 35, C [mm] is the supply / conveyance screw 35 screw shaft diameter, and R1 [rpm] is the supply
The rotation speed of the transport screw 35, P [mm] is the pitch of the supply / transport screw 35, K [g / cm ³ ] is the bulk density of the developer, and α is the developer supply rate.

The supply rate α is a coefficient which mainly changes depending on the positional relationship between the developing roller 31 and the supply means, and is constituted by a supply / conveyance screw 35 and a water wheel 36 below the developing roller 31 as shown in FIG. Supply means are arranged,
A collecting means including a stripping roller 37, a stripping member 38, and a collection / conveyance screw 39 has a structure arranged above the developing roller 31. The rate α indicates a value of 0.35.

A = 30 mm, Ds = 60 mg / cm ² ,
L1 = 306 mm, B = 24 mm, C = 8 mm, P1 =
30 mm, R1 = 367 rpm, K = 1.90 g / cm
^{3. When the} supply rate α = 0.35, the rotation speed Rs of the developing roller 31 is set to 170 rpm or less. In an example where the supply unit is disposed at a position higher than the developing roller 31,
The supply rate α = 0.70 is obtained. In this case, the rotation speed Rs of the developing roller 31 can be set at 340 rpm or less.

The image forming apparatus is provided with an image density adjusting function for adjusting the image density for various purposes. That is,
These include image density adjustment performed in accordance with operator settings, image density adjustment for correcting changes in the characteristics of the developer and the photoconductor, and image density adjustment for correcting changes in the environment. These image density adjustments can be performed by changing the number of rotations of the developing roller 31 within a range satisfying the expression (1) (A method). However, by controlling the charging device 22, the electrostatic latent image can be adjusted. Performing by controlling the image voltage or controlling the developing bias applied to the developing roller 31 in the developing device 24 (B method)
It is also possible to use the method A and the method B in combination.

When the number of revolutions of the developing roller 31 is changed, the stirring time for changing the number of revolutions is slightly longer in order to make the entire developer circulating in the developing device 24 stable and stable. It is desirable to do. Such stirring may be performed during the execution of the image forming step or may be performed during idling.

In the present embodiment, the peeling roller 37 is driven independently of the developing roller 31. Therefore, even when the rotation speed of the developing roller 31 is changed to change the image density as described above, the rotation speed of the peeling roller 37 is not changed, and the rotation is driven at a constant rotation speed. When the rotation speed of the stripping roller is reduced, the developer slips through between the stripping roller 37 and the stripping member 38, and the slipped developer remains on the stripping roller 37 or transfers to the developing roller 31. In some cases, the peeling performance may be reduced and affect the image. Stripping roller 3
In a configuration in which the developing roller 7 is driven by a common drive unit with the developing roller 31, such an undesirable phenomenon is likely to occur when the rotation speed of the developing roller 31 is reduced. The above phenomenon can be prevented by driving independently of the roller 31 and keeping the rotation speed of the peeling roller 37 unchanged.

In the above-described configuration in which the peeling roller 37 is driven independently of the developing roller 31, the supply means including the stirring / transport screw 34, the supply / transport screw 35, and the water wheel 36 is driven in common with the peel roller 37. It is desirable to drive with.

In the present embodiment, the peeling roller 37 is driven independently of the developing roller 31 as described above, but this configuration prevents deterioration of image quality due to environmental changes.

As a result of changes in the properties of the developer due to changes in the environment, that is, changes in temperature and / or humidity,
It has been confirmed that the amount of the developer conveyed on the developing roller 31 while being regulated by the regulating member 33 as the regulating means changes. If the number of rotations of the peeling roller 37 is not changed in response to the change in the amount of developer transported, for example, when the amount of developer transported under low temperature and low humidity becomes large, the peeling roller 37 can sufficiently remove the developer. Since the developer is not peeled off, the developer stays on the developing roller 31 to affect development. In order to cope with such a phenomenon, in the present embodiment, control is performed to change the number of revolutions of the peeling roller 37 in response to a change in the environment, thereby maintaining a constant image quality with respect to the change in the environment. are doing. That is, an environment sensor 29 is provided as environment detection means for detecting at least one of the temperature and the relative humidity, and the number of rotations of the peeling roller 37 is controlled based on the detection result of the environment sensor 29.

Table 1 shows an example of correction control for environmental changes in the rotational speed r0 of the developing roller 31 and the rotational speed r1 + r2 of the peeling roller 37. Table 1 shows the developing roller 31
This is an example of a case where a roller having a diameter of 30φ and a roller having a diameter of 18φ are used as the peeling rollers 37. The rotation speed of the peeling roller 37 is set by setting an appropriate value for the temperature change as the reference value r1 and correcting the reference value r1 by the correction value r2 for the humidity change (calculating r1 + r2). The correction table for such an environment is stored in the nonvolatile memory of the control means MC (shown in FIG. 9).

[0096]

[Table 1]

By performing the correction shown in Table 1 with respect to environmental changes, an image having a good image quality is always formed without being affected by environmental changes.

The developing roller 31 and the peeling roller 37 have rough surfaces, and the developer is conveyed by utilizing the frictional action of the rough surfaces. In addition, it has been confirmed that the use of these rollers over a long period of time causes the roughened surface to wear, causing a change in the developer transportability. Developing roller 31
When SUS is used as the material, the material is durable and has a relatively low degree of wear, but it is still desirable to take measures against wear. Stripping roller 37
When aluminum is used as the material, it is desirable to make correction for the above-mentioned wear.

Table 2 shows the developing roller 31 and the peeling roller 3
7 shows an example of correction of the number of rotations of these rollers with respect to the sliding time of No. 7. Table 2 shows an example in which a SUS roller having a diameter of 30φ is used as the developing roller 31, and an aluminum roller having a diameter of 18φ is used as the peeling roller 37.

[0100]

[Table 2]

In Table 2, the sliding distance 1 corresponds to the developing roller 3
1 is the movement distance of the surface, which is a value obtained by multiplying the circumferential length of the roller surface by the cumulative value of the number of rotations of the roller, and has a unit of kilometer (km). The sliding distance 2 is the peeling roller 37
And the unit is kilometer (km).

The rotational speed r0 of the developing roller 31 is increased in accordance with the increase of the sliding distance 1, and the rotational speed of the peeling roller 37 is set to a value obtained by adding the corrected rotational speed r2 to the reference value r1. , Constant developing performance and stripping performance are obtained.

In Table 2, as in Table 1, the number of rotations of the peeling roller 37 is divided into the reference number of rotations r1 and the number of corrections, stored in the memory of the control means MC, and used for correction.

By performing the correction shown in Table 2, a stable high-quality image is formed over a long period of time.

When it is not necessary to correct the rotation speed of the developing roller 31 using a highly durable SUS, for example, a correction table as shown in Table 3 is used. Table 3
In the example, the rotation speed r0 of the developing roller 31 is maintained at a constant value irrespective of the sliding distance 1, and the peeling roller 3
The rotation number 7 is also corrected as the rotation number obtained by adding the supplementary rotation number r2 to the reference rotation number r1 in response to the increase in the sliding distance 2.

[0106]

[Table 3]

As described above, in the configuration in which the peeling roller 37 is driven independently of the developing roller 31, it is desirable to set the number of rotations to a certain value or more to secure the peeling performance. That is, the rotation speed Rr of the peeling roller 37 is set to R
It is desirable that r ≧ RsMax (A / E). Here, RsMax is the maximum value of the number of revolutions of the developing roller 31 in which development is performed without causing the above-described developer conveyance failure, and the developer conveyance failure phenomenon indicated by the curve FP shown in FIG. 5 does not occur. This is the highest value of the rotation speed. A is the diameter of the developing roller 31, and E is the diameter of the peeling roller. When the rotation speed Rr of the peeling roller 37 falls below the above condition,
The developer tends to slip through.

When the peeling roller 37 is driven independently of the developing roller 31 as described above, the start and stop of the driving of the peeling roller 37 when the operation of the developing device 24 is started and stopped is determined. Is desirably related to the driving of

That is, when the operation of the developing device 24 is started, the driving of the peeling roller 37 is started before the driving of the developing roller 31 is started, and when the developing device 24 is stopped, the peeling roller 37 is driven after the driving of the developing roller 31 is stopped. It is desirable to stop driving. Thus, the peeling roller 37
If the condition that the driving time of the developing roller 31 includes the driving time of the developing roller 31 is not satisfied, the developer on the developing roller 31 is difficult to peel off and easily slips through, so that the image quality is affected or the developer is scattered. May occur.

FIG. 9 is a block diagram of a control system according to the second embodiment of the present invention. The control means MC including a microcomputer controls the bias power supply 31E of the charging device 22 or the developing roller in accordance with the setting of the image density in the operation unit OP.
Is controlled to adjust the image density. Further, the control unit MC controls the drive motor 31D of the developing roller 31 together with the drive motor 21D of the photoconductor 21 based on a pixel density conversion command signal, for example, to change and control the respective rotation speeds. In the control for changing the number of revolutions of the developing roller 31, the control means MC performs control for keeping the drive motor 37D of the peeling roller 37 constant. Further, the control means MC includes a temperature sensor 29 which constitutes the environment sensor 29.
T, the drive motor 37D is controlled based on the detection information from the humidity sensor 29H to control the rotation speed of the peeling roller 37 to an appropriate value. Further, the control means MC includes a motor 31D.
Is the first integrating means for calculating the information on the cumulative number of rotations of the developing roller 31 from the operation information and the sliding distance on the surface of the developing roller 31 from the information on the cumulative number of rotations. Control the speed. Similarly,
The control means MC is a second integrating means for obtaining information on the cumulative number of rotations of the peeling roller 37 from the operation information of the motor 37 and the sliding distance of the surface of the peeling roller 37 from the information on the cumulative number of rotations. The number of rotations of the motor 37D is controlled based on the moving distance.

[0111]

According to the first, fifth, sixth, seventh and eighth aspects of the present invention, high image quality can be maintained by preventing density unevenness and always ensuring stable developer circulation.

According to the second or tenth aspect of the present invention, the gradation of the image and the maximum density are adjusted while maintaining the stability of the circulation of the developer in the developing device. An image can be formed.

According to the invention of claim 3 or 11, for example,
In the case of pixel density conversion or the like, it becomes possible to appropriately adapt the developability of the developing device.

According to the fourth or twelfth aspect of the present invention, the image density can be stably adjusted, and the developing device can appropriately cope with other image forming conditions.
Under various image forming conditions, a high quality image can be stably formed.

According to the ninth aspect of the present invention, since the toner concentration of the developer contributing to the development is accurately detected, it is possible to always maintain the toner concentration properly.

According to the thirteenth aspect of the present invention, there is little stagnation of the developer in the developing device having the configuration in which the supply means is disposed below the developing roller, and a clear image can always be formed.

According to the fourteenth and fifteenth aspects of the present invention, even when the rotation speed of the developing roller is reduced, the developer is effectively prevented from slipping out in the developer collecting section, and the image quality is prevented from being deteriorated due to the slipping phenomenon. You.

According to the sixteenth aspect of the present invention, even when the number of rotations of the developing roller is changed, the stirring and transporting performance of the developer in the image device is properly maintained, and a high quality image is stably obtained. Can be formed.

According to the invention of claim 18 or 21, a stable image can be formed with respect to environmental changes.

According to the nineteenth aspect, a change in developability due to wear of the developing roller is prevented, and high image quality is always maintained.

According to the twentieth aspect, a change in developability due to wear of the peeling roller is prevented, and high image quality is always maintained.

According to the invention of claim 22, 23 or 24,
When the developing roller and the stripping roller are driven by different driving means, it is possible to prevent the occurrence of image unevenness and the scattering of the developer when the developing device is started or stopped.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flow of a developer in a conventional developing device.

FIG. 2 is a diagram showing a first embodiment of the present invention.

FIG. 3 is a diagram illustrating a flow of a developer according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a distribution of a developer amount in a supply unit.

FIG. 5 is a graph showing the amount of developer conveyed with respect to the number of rotations of a developing roller.

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

FIG. 7 is a diagram showing a main part of a second embodiment of the present invention.

FIG. 8 is a diagram showing a flow of a developer according to a second embodiment of the present invention.

FIG. 9 is a block diagram of a control system according to a second embodiment of the present invention.

[Explanation of symbols]

 1,21 photoconductor 4,24 developing device 10,30 outer frame 11,31 developing roller 13,33 regulating member 14,35 supply / transport screw 15,38 stripping member 16,39 collection / transport screw 17 partition plate 34 stirring・ Conveying screw 36 Water wheel 37 Stripping roller CH1 Developing unit CH2 Supply unit CH3 Recovery unit CH4 Stirring unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/00 303 G03G 15/08 507C (72) Inventor Naoto Tokutake 2970 Ishikawacho, Hachioji-shi, Tokyo Konica shares In-company (72) Inventor Motofumi Kawamoto 2970, Ishikawa-cho, Hachioji-shi, Tokyo Konica Intra-company (72) Inventor Hideika Sata 2970, Ishikawa-cho, Hachioji-shi, Tokyo In-company Konica (72) Inventor Nobuyasu Tamura 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation F term (reference) 2H027 DA02 DA04 DA13 DA14 DD07 EA04 EA05 EA06 EB03 EC06 EC19 ED08 ED09 2H077 AA37 AB02 AB03 AB14 AC02 AC03 AC16 AD06 AD13 AD18 AD31 AD32 AD35 BA01 BA02 BA03 DA10 DA18 DA24 DA42 DA78 DB08 DB14 DB18 DB21 DB25

Claims (24)

[Claims] A developing unit, a supplying unit, and a collecting unit separated from the supplying unit at least within a range of a developing width. The collecting unit includes a plurality of fixed magnets. A developing roller that conveys, a regulating unit provided in the developing unit, and regulates an amount of the developer conveyed to the developing region; A supply unit that supplies a developer to the developing unit; and a developing device that is provided in the collection unit and has a collection unit that returns the developer on the developing roller to the supply unit. In the image forming apparatus, the diameter of the developing roller is A [mm], the amount of the developer conveyed on the developing roller regulated by the regulating means is D [mg / cm ² ], and the conveying width of the developer is Is L [mm] Wherein the diameter of the supply-conveying screw B [mm], the supply and
The screw shaft diameter of the transport screw is C [mm], the rotation speed of the supply / transport screw is R1 [rpm], the pitch of the supply / transport screw is P [mm], and the bulk density of the developer is K [g / cm]. ³ ], when the developer supply rate is α, the rotation speed Rs [rp] of the developing roller satisfying the following condition:
m], Rs ≦ {25 × α × K × (B ² −C ² ) × P × R 1} /
(D × A × L). 2. The method according to claim 1, wherein a rotation speed of the developing roller is not changed.
2. The image forming apparatus according to claim 1, wherein the image density is controlled by controlling at least one of a voltage of the electrostatic latent image and a developing bias. 3. The image forming apparatus according to claim 1, wherein the number of rotations of said developing roller is variable. 4. The image forming apparatus according to claim 1, wherein the number of rotations of said developing roller is variable, and image density is controlled by controlling at least one of a voltage of an electrostatic latent image and a developing bias. Image forming apparatus. 5. A fixing device comprising: a developing section, a stirring section, a supply section separated from the stirring section at least within a developing width, and a collecting section separated from the supplying section at least within a developing width. A developing roller that contains the magnet that has been formed and conveys the developer to a developing area in the developing section; a regulating means that is provided in the developing section and regulates a conveying amount of the developer conveyed to the developing area; A stirring and conveying screw that conveys the developer in the direction of the rotating shaft while stirring, a supply and conveying screw that conveys the developer in the direction of the rotating shaft while stirring and supplies the developing unit to the developing unit, A developing device that is provided in the collecting unit and has a collecting unit that collects the developer from above the developing roller and returns the developer to the downstream side of the flow of the developer from outside the range of the developing width on the downstream side in the supply unit. Preparation In the image forming apparatus, the collection unit includes a collection / conveyance screw that conveys the developer collected from the developing roller in a rotation axis direction of the developer. The collection / conveyance screw stirs the collected developer. Forming a circulating transport system for the developer returning from the stirring section to the stirring section via the supply section, the developing section, and the recovery section by returning to the upstream portion of the flow of the developer in the section; The stirrer and the supply unit are provided below, and the recovery unit is provided above the unit. The diameter of the developing roller is A [mm], and the diameter of the developing roller is regulated by the regulating unit. The transport amount of the developer to be transported is D [mg / cm ² ], and the transport width of the developer is L [m
m], the diameter of the supply / transport screw is B [mm], and the screw shaft diameter of the supply / transport screw is C [m
m], the number of rotations of the supply / conveyance screw is R1 [rp
m], and the pitch of the supply / transport screw is P [m
m], the bulk density of the developer is K [g / cm ³ ], and the supply rate of the developer is α. The rotation speed Rs [rp] of the developing roller satisfying the following conditions.
m], Rs ≦ {25 × α × K × (B ² −C ² ) × P × R 1} /
(D × A × L). 6. The image forming apparatus according to claim 5, wherein the collecting unit includes a peeling roller that peels off the developer on the developing roller. 7. The image forming apparatus according to claim 5, further comprising a water wheel for conveying the developer conveyed by the supply / conveyance screw to the developing roller. 8. A toner replenishing section for replenishing toner in the upstream section of the stirring section.
8. The image forming apparatus according to claim 7. 9. A toner replenishing position in the upstream portion is located on a downstream side of a flow of the developer from a position where the developer is returned from the collecting portion, and is located between the returned position and the toner replenishing position. The image forming apparatus according to any one of claims 5 to 8, further comprising a toner concentration detecting unit configured to detect a toner concentration of the developer. 10. The image forming apparatus according to claim 5, wherein the image density is controlled by controlling at least one of the voltage of the electrostatic latent image and the developing bias without changing the rotation speed of the developing roller. The image forming apparatus according to claim 1. 11. The image forming apparatus according to claim 5, wherein the rotation number of the developing roller is variable. 12. The image forming apparatus according to claim 5, wherein the number of rotations of said developing roller is variable, and image density is controlled by controlling at least one of a voltage of an electrostatic latent image and a developing bias. The image forming apparatus according to claim 1. 13. The image forming apparatus according to claim 1, wherein the supply rate α is 0.35 or more. 14. A developing roller for transporting the developer to the developing area by rotation, a supply unit for supplying the developer to the developing roller by rotation, a regulating unit for regulating a transport amount of the developer transported to the developing area, An image forming apparatus provided with a developing device having a collecting unit for collecting a developer from the developing roller, wherein the collecting unit includes a plurality of fixed magnets and peels off the developer from the developing roller. A roller for driving the peeling roller independently of the developing roller, and changing the rotational speed of the developing roller to change the developing property of the developing device. An image forming apparatus characterized in that: 15. When the diameter of the developing roller is A [mm], the diameter of the peeling roller is E [mm], and the maximum value of the rotational speed of the developing roller is RsMax, the rotational speed of the peeling roller is Rr, Rr ≧ RsMax
The image forming apparatus according to claim 14, wherein (A / E) is set. 16. A developing roller for transporting a developer to a developing area by rotation, a supply unit for supplying the developer to the developing roller by rotation, a regulating unit for regulating a transport amount of the developer transported to the developing area, An image forming apparatus provided with a developing device having a collecting unit for collecting a developer from the developing roller, wherein the collecting unit includes a plurality of fixed magnets and peels off the developer from the developing roller. A roller, wherein the stripping roller and the supply unit are driven by a common driving unit, and the developing roller is driven by a driving unit different from the driving unit of the stripping roller and the supply unit. An image forming apparatus comprising: 17. When the diameter of the developing roller is A [mm], the diameter of the peeling roller is E [mm], and the maximum value of the rotational speed of the developing roller is RsMax, the rotational speed of the peeling roller is Rr, Rr ≧ RsMax
17. The image forming apparatus according to claim 16, wherein (A / E) is set. 18. A developing roller for transporting a developer to a developing area by rotation, a supply unit for supplying the developer to the developing roller by rotation, a regulating unit for regulating a transport amount of the developer transported to the developing area, and An image forming apparatus provided with a developing device having a collecting unit for collecting a developer from the developing roller, wherein the collecting unit includes a plurality of fixed magnets and peels off the developer from the developing roller. A roller for driving the peeling roller independently of the developing roller, and having an environment detecting means and a control means, wherein the controlling means controls the peeling roller based on detection information of the environment detecting means. An image forming apparatus for controlling the number of rotations of the image forming apparatus. 19. A developing roller for transporting a developer to a developing area by rotation, a supply unit for supplying the developer to the developing roller by rotation, a regulating unit for regulating a transport amount of the developer transported to the developing area, An image forming apparatus provided with a developing device having a collecting unit for collecting a developer from the developing roller, wherein the collecting unit includes a plurality of fixed magnets, and peels off the developer from the developing roller. A first integrating means for driving the stripping roller independently of the developing roller and integrating a sliding distance of a surface of the developing roller, based on an integration result of the first integrating means. An image forming apparatus having a control unit for controlling the number of revolutions of the developing roller. 20. A developing roller for transporting the developer to the developing area by rotation, a supply unit for supplying the developer to the developing roller by rotation, a regulating unit for regulating a transport amount of the developer transported to the developing area, and An image forming apparatus provided with a developing device having a collecting unit for collecting a developer from the developing roller, wherein the collecting unit has a peeling roller for peeling the developer from the developing roller, and A second integrating means which is driven independently of the developing roller and integrates a sliding distance of the surface of the stripping roller, and controls the rotation speed of the stripping roller based on the integration result of the second integrating means. An image forming apparatus comprising a control unit. 21. When the diameter of the developing roller is A [mm], the diameter of the stripping roller is E [mm], and the maximum value of the number of rotations of the developing roller is RsMax, the number of rotations of the stripping roller is Rr, Rr ≧ RsMax
The image forming apparatus according to claim 18, wherein (A / E) is set. 22. A developing roller for transporting the developer to the developing area by rotation, a supply unit for supplying the developer to the developing roller by rotation, a regulating unit for regulating a transport amount of the developer transported to the developing area, An image forming apparatus including a developing device having a collecting unit that collects a developer from the developing roller, wherein the collecting unit is driven independently of the developing roller,
An image forming apparatus, comprising: a peeling roller that peels off a developer on the developing roller, wherein the peeling roller is driven to rotate for a time that includes a rotation time of the developing roller. 23. The image forming apparatus according to claim 22, wherein the rotation of the peeling roller is started earlier than the rotation of the developing roller when the operation of the developing device is started. 24. The image forming apparatus according to claim 22, wherein the stop of the peeling roller when the developing device is stopped is delayed from the stop of the developing roller.