JP3483479B2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
Copier, laser beam printer, facsimile,
The present invention relates to a developing device used for a printing device or the like. [0002] 2. Description of the Related Art Conventionally, uniform charging has been performed on an electrostatic latent image carrier.
After exposure to analog exposure or semiconductor laser or LED
Image exposure to form an electrostatic latent image on the electrostatic latent image carrier
After the formation, this electrostatic latent image is converted into a developer image by a developing device.
After the developer image is transferred to a transfer material,
The material is separated from the electrostatic latent image carrier and sent to the fixing device.
The developer image is fixed on the transfer material in the
2. Description of the Related Art An image forming apparatus that outputs an image is known. Here, the image forming process will be described with reference to FIG.
I will tell. FIG. 14 is a sectional view of a main part of the image forming apparatus.
The image forming apparatus is, for example, a photosensitive
The photosensitive drum 1 has an OP on its surface.
A photoconductive layer of C, a-Si, etc.
Be moved. The surface of the photosensitive drum 1 is
For example, it is uniformly charged to, for example, -700V. Then, the image signal
Exposure on photosensitive drum 1 by performing image exposure 12 based on information
Attenuates the surface potential of the section to, for example, -200 V
A latent image corresponding to the image signal of the image is formed on the system 1. still,
The image exposure 12 includes, for example, a semiconductor laser or an LED array.
Is used. Next, a developing device which is a one-component developing device for developing a latent image
2 and visualized as a toner image. In addition, dry type
A developing device using a one-component developer is simple and exchanges a carrier or the like.
It has a high durability and a long service life because no replacement is required.
For example, jumping current using magnetic one-component toner
An image or the like is employed. [0006] The developing device 2 has a negatively charged black toner.
Is used, and the developer vial is
Latent image by applying a DC bias of about -500 V
Is visualized as a toner image by reversal development. After that,
Pre-transfer treatment (usually using a charger 10 if necessary)
Is to apply DC or AC corona or remove electricity
Is combined) and supplied to the photosensitive drum 1.
Transfer toner image onto the transferred transfer material by the transfer charger 4
You. Then, the transfer material on which the toner image has been transferred is fixed to the fixing device 7.
To fix the toner image on the transfer material
To get the image. The transfer residual toner on the photosensitive drum 1 is
Removed by the cleaning device 6 to prepare for the next image formation
available. [0007] By the way, in order to increase the speed of the image forming apparatus,
Indicates the development using a two-component magnetic brush in the developing device.
A plurality of developing rolls of the apparatus can be used (Japanese Unexamined Patent Publication No.
204084), the distance between the developing sleeve and the photosensitive member.
Move the separation closer to the downstream developing sleeve and
The toner supply amount is made uniform (Japanese Patent Laid-Open No. 2-18 / 1990).
8778). [0008] Further, there are a plurality of miniaturized developing sleeves.
Developing device (Japanese Patent Publication No. 3-5579)
Report). [0009] SUMMARY OF THE INVENTION
The conventional developing device has the following problems. That is, a plurality of developer carriers (developing sleeves)
A developing device having excellent development density is excellent in maintaining the density.
If there is no toner layer thickness regulating member between the
Although they are highly efficient and save space,
Has the following problems. 1. Developing device having a plurality of developing sleeves
In, the regulation of the toner layer thickness of the upstream developing sleeve
While a magnetic blade or the like is used,
Reeve controls the toner layer thickness at the upstream developing sleeve.
For this reason, the upstream developing sleeve is in addition to the normal thickness regulation.
To regulate the toner layer thickness at the bottom
More passes through the toner layer thickness regulating member than the image sleeve
And the degree of friction on the sleeve surface increases.
As a result, the shaving degree of the coating material is
Is different between the developing sleeve and the upstream developing sleeve.
The life of the leave was different. Therefore, the developing sleeve
Service intervals are different and service personnel frequently
Need to visit users, waste service costs
I was 2. Also, the toner layer thickness of the downstream developing sleeve
In the development method where regulation is performed by the upstream development sleeve,
Upstream developing sleeve layer thickness regulation method and downstream developing three
The method of regulating the layer thickness of
Counter rotation with respect to the upstream developing sleeve
The toner is rubbed violently to enforce thickness regulation, and the same toner
But the tribo was considerably higher than the upstream. this
For this reason, develop with the upstream developing sleeve and the downstream developing sleeve.
Characteristics, and are common for space saving and cost reduction.
When image bias is used, developability is
It was different, and it was difficult to control the concentration. this is
Recent digital images and images compatible with graphics
This was in conflict with the demand for gradation and gradation stability.
This phenomenon is caused by the fact that the magnetic charge amount is small and the magnetic property is low.
This is particularly severe when a component toner is used. 3. Three not coated with SUS etc.
In sleeves, a sleeve that retains the afterimage of the previous image at the sleeve pitch
A ghost image has occurred. In addition, high-speed machine
The development time is short because
Is not maintained, resulting in unstable developability and a change in density.
The movement was growing. Thus, solving the above problems simultaneously
Was difficult. Therefore, the first object of the present invention is to
Toner carrierService by sharing the service life of
Service costs are reduced by eliminating the need for manual maintenance
To provide a developing device that can reduce
You. The second object of the present invention is as follows.Tona
-CarrierDigital images of recent years have been eliminated
Gradation and gradation of images corresponding to images and graphics
Provide a developing device that can meet the requirements for stability
It is in. Further, the third object of the present invention is as follows.
No leave ghost, developability and density for high speed
To provide a developing device that can stabilize
is there. [0018] Means for Solving the Problems To achieve the above object,
,BookThe invention is directed to the rotation direction of the electrostatic latent image carrier.Side by side
And carry the upstream and downstream toner rotatable in the same direction.
And the toner layer thickness on the toner carrier on the upstream side
Blade andAnd each toner carrier is
Non-magnetic member around the conductive member and coating part covering it
LumberAnd inMake up,Toner on downstream toner carrierLayer thickness
RegulationsIt is configured to be performed by the toner carrier on the upstream side
In the developing device,SaidTrees that make up the coating material
FatB, crystalline graphite mixed with resin, and
Conductive carbon or titanium oxide and conductive carbon
Where P is the weight of the toner carrier on the downstream side,
The weight ratio P / B of the carrying member is
Of theGreater than weight ratio P / BdidThat
Features. [0019] [0020] [0021] [0022] Embodiments of the present invention are attached below.
Description will be given based on the drawings. <Embodiment 1> FIG. 3 shows a developing device according to the present invention.
FIG. 2 is a cross-sectional view of a main part of the image forming apparatus including the apparatus,
The image forming apparatus has a process speed of 460 mm / sec.
A black-and-white digital copier capable of outputting 92 sheets per minute.
A-Si photosensitive drum having a diameter of 108 mm
1 is used. a-Si is more attractive than organic photoreceptor
OP is as large as about 10 and the charging potential is relatively low.
Although latent image potential is not sufficient compared to C, high durability and long life
It is suitable for high-speed machines because there are more than 3 million
Have signs. The photosensitive drum 1 is, for example,
After being uniformly charged to 500 V, image exposure at 600 dpi
12 is made. Image exposure 12 uses semiconductor laser as light source
As a first laser modulated by a first image signal
The first laser beam is driven by a motor.
Polarized by a polygonal mirror rotating at a constant rotation speed,
After being reflected by the turning mirror
1 is raster-scanned, and the surface potential of the exposed portion is
Attenuates to + 100V to form an image-like latent image on photosensitive drum 1.
To achieve. The wavelength of the laser beam is 680 nm.
You. Thereafter, the latent image formed on the photosensitive drum 1
Is developed by the developing device 2 to form a visible image as a toner image.
Become Then, the electrostatic latent image is developed by the developing device 2 and the toner
-After being visualized as an image, the total current is
(AC + DC) -200 μA flows to charge the toner image
After the transfer, the transfer charger 4 moves the transfer material in the direction of the arrow.
Transfers the toner image and fixes the transfer material on which the toner image has been transferred.
The toner image is sent to the device 7 and fixed on the transfer material. In addition, feeling
The transfer residual toner on the optical drum 1 is removed by the cleaning device 6.
To prepare for the next image formation. In this embodiment, the developing device 2 has a simple structure.
Easy maintenance with up to 2000k development sleeve life
Unnecessary and highly durable black magnetic one-component developer
The used development is performed. In this embodiment, a plurality of developers are used.
Regular development using the carrier (developing sleeve) 20, 30
Do. The operation of toner replenishment is performed in the vicinity of 2B shown in FIG.
Is lost, the signal from the piezoelectric element 22 causes
The roll 24 is driven to rotate, and this magnet roll
24 rotates the toner from the hopper 9B to the developing device.
It is replenished in 2. Next, details of the developing device 2 according to the present invention will be described.
Will be described with reference to FIGS. FIG. 1 shows the present invention.
FIG. 2 is a sectional view of the developing device, and FIG.
FIG. In the developing device 2 according to the present embodiment,
High durability and high reliability with simple maintenance and no maintenance required
And a one-component magnetic toner having high productivity and a negative polarity was used. G
The toner is a negative toner having a particle size of 7.0 μm and S as an external additive.
iO_Two 1.0% by weight. As shown in FIG.
The two developer sleeves 20 and 30 are used as developer carriers.
The first developing sleeve 20 is provided with a non-magnetic member.
On aluminum A2017 with a diameter of 30 mm
After blasting with FGB # 300,
It is constructed by coating. Also, the second
The developing sleeve 30 is also a non-magnetic member having a diameter of φ20.
mm aluminum A2017 on FGB # 300
It is composed by blasting and coating
You. This coating forms a film that protects the A1 surface.
Which is formed in the sleeve cycle
Prevents ghost images and durable sleeve surface
It is applied to enhance sex. As the material of the sleeve tube
Means that a heater is also used when an a-Si drum is used.
For example, if the heat conductivity is poor such as SUS,
Thermal eccentricity tends to cause sleeve pitch unevenness images.
Therefore, a material having good thermal conductivity such as Al is preferable. Next, the magnetic seal member will be described. As shown in FIG. 4 and FIG.
The sleeve 20 and the second developing sleeve 30 both have 6 poles (N
1 to N3, S1 to S3), and both developing sleeves
A magnet having a shape as shown in FIG.
The air seal member 13 is located near both ends of the developing sleeves 20 and 30
It is provided in. Then, the developing sleeves 20 and 30
The gap between the surface and the magnetic seal member 13 is 420 μm ±
It is set to 100 μm. The magnetic seal member 13
Is a moldalloy made mainly of iron (KN plating, permeability 1)
0.6). In addition, the first and second magnets
The lengths are both set to 305 mm. Regarding the mounting position of the magnetic seal member 13,
The proper position of the magnetic seal with respect to the magnet
Align the outer edge of the magnet with the edge of the magnet
Is most preferred. This is a magnet from outside the magnetic seal
When the unit goes out, magnetic force exists outside the longitudinal direction.
The magnetic force will cause the toner to be carried out, causing toner leakage.
Is to cause. Conversely, outside the magnetic seal
On the other hand, if the end of the magnet is too
Forming a magnetic brush between the conductive seal and the magnet
-A magnetic seal that eliminates leakage is located at the outer end of the magnetic seal.
Despite the absence of magnetic force, magnetic
To form a magnetic brush with the width of the seal, the outer toner
Is leaked to the edge and the toner layer thickness increases at the same time.
It may fall. In the longitudinal direction, the developing sleeve 20,
Because there is backlash due to the relationship between 30 and the magnet,
1 mm from the magnet end as shown in FIG.
Side so that the magnetic seal member 13 is located
Was. By the way, in the first developing sleeve 20,
As shown in FIGS. 4 and 5 and Table 1, 6 poles (N1 to N3, S
Built-in fixed magnet with magnetic field pattern of 1-3)
Have been. [0035] Further, the first developing sleeve 20 is
It rotates at a speed of 20% and is carried on the developing sleeve 20.
The thickness of the toner is regulated by the magnetic blade 20A.
Gap S-Bga between image sleeve 20 and magnetic blade 20A
p is set to 250 μm. And the first development
The gap S-Dgap between the sleeve 20 and the photosensitive drum 1 is 23
0 μm, and +200 V
DC bias and Vpp 1400V as shown in FIG.
A square wave of several 2.7 kHz is applied as an AC bias.
The magnetic one-component non-contact development is performed. Therefore,
Trust fog removal (300V in the flight direction)
(Return) The contrast becomes 100V. As the second developing sleeve 30, a non-magnetic portion
Film on aluminum A2017 with diameter of φ30mm
Is used, and the inside thereof is shown in FIGS.
And 6-pole (N1-N3, S1-S3) magnetic fields shown in Table 2.
A magnet consisting of turns is provided. [0037]+200 V DC bias is applied to the second developing sleeve 30
And Vpp 1400V shown in FIG.
Although a shape wave is applied, the second developing sleeve 30
One developing sleeve 20 is the same and common, and has one power supply.
Cost can be reduced and space for power supply can be reduced.
It has the advantage of requiring less. The second developing sleeve 30 is attached to the photosensitive drum 1.
The developing sleeve 30 rotates at a speed of 150% with respect to the developing sleeve 30.
The gap S-Dgap with the photosensitive drum 1 is set to 230 μm.
Have been. By the way, the magnetic blades 20A, 30A
Both are plate-like magnetic blades having a thickness of 1.0 mm.
The regulation of the toner layer thickness on the developing sleeve 30 is based on the upstream developing sleeve.
Performed by leave 20. The first developing sleeve 20 and the second developing sleeve
The distance between the image sleeves 30 is set to 300 μm. This
Is the value of the toner in the first and second developing sleeves 20 and 30.
This is a value for making the supply amounts equal. This
The toner on the developing sleeves 20 and 30
-Coating amount (M / S) is about 1.0mg / cm^TwoAnd
The S-Dgap of the second developing sleeve 30 is 230 μm.
You. There are several ways to equalize the toner supply per unit time.
Match the developing characteristics of the developing sleeve to stabilize gradation
This is the most important in enabling control. In recent years, digital images and graphics
To meet the requirements of image gradation and gradation stability
In order to obtain the characteristics, the developing characteristics of the developing sleeves 20 and 30 are required.
It is most important that the (first and second development characteristics) match.
Is an important task. Toner for both developing sleeves 20 and 30
The supply amount is equal, and the developing amount of the first developing sleeve 20 is
The pole is S1, and the magnetic force and half width of both are the same. I
However, as shown in FIG.
(The upper is the second development and the lower is the first development). This will be described below. This is because the first developing sleeve 20 has a magnetic brake
20A, while the second development
Leave 30 is regulated by first developing sleeve 20.
In both cases, the first developing sleeve 20 is the second developing sleeve 30
Rotation in the direction opposite to the toner
You. Therefore, the second developing sleeve 30 and the first developing three
The toner is strongly compressed and rubbed between the brushes 20, and the friction of the toner is
The charging ability is higher than that of normal magnetic blade regulation.
That is, compared with the first development, the second development is tribo (Q / M)
Becomes larger. Generally, the developing characteristics are tribo (Q / M) × toner
-Tribo (Q / M) because it depends on supply amount (M / S)
The difference between the VD car and the development characteristic as shown in FIG.
Appear on the screen. This tendency is at a process speed of 400 mm /
If the development time is not sufficient, such as a high-speed machine
And the developing sleeve rotation speed is high and the toner layer thickness
This is noticeable when the frictional force on the toner is large at the regulating member.
You. Then, this difference corresponds to the development characteristics (30 k sheets) shown in FIG.
Time). In FIG. 8, the horizontal axis is contrast.
The vertical axis indicates the V-D characteristic, in which the vertical axis represents the concentration at the potential Vcont (V).
It is something. Next, the second problem, that of developing sleeve
The life will be described. The developing device 2 according to the present invention comprises a developing sleeve 2
Compact structure because there is no member between 0 and 30
It has become. In this method, the first developing sleeve 20
After restricting the toner with the magnetic blade 20A, the second current
The toner of the image sleeve 30 is regulated. That is, the development three
Receives two shares with toner during one rotation of valve 20
You. On the other hand, the second developing sleeve 30 is a shell at the regulating portion.
Take a once. That is, in the image forming durability,
The surface of the image sleeve 20 is on the surface of the second developing sleeve 30
Received about twice the market share and the first amount of shaved coat
The number of developing sleeves 20 increases. This is the first development
Coat life of sleeve 20 and second developing sleeve 30
Life is different. Therefore, the life of one developing sleeve has not been reached yet.
Despite that, the other developing sleeve must be replaced first.
After that, if another developing sleeve is replaced,
The cost of Bisman increases, and the life of the developing sleeve
Is expected to be common. The present embodiment has been implemented in view of the above.
It is something. Table 3 shows the film formulation, the amount of shaving, and the tribo for the conventional system.
(Q / M), toner supply amount (M / S) and tribo (Q / M
M) × Toner supply amount (M / S). [0049] The formula of the film is A1 sleeve surface with phenolic resin and crystalline
100: 36: 4 weight ratio of graphite and carbon
Mix in proportions and cure at a temperature of 150 ° C with a film thickness of 10μm
The film was used. To form a stable and uniform film
The film thickness is suitably about 10 μm. In this case, the P / B ratio
Is 1 / 2.5. B is the weight of the resin, and P is less than the resin.
Weight of outer pigment (crystalline graphite + carbon)
Quantity. As can be seen from Table 3, in the conventional system, 500
While the second developing sleeve is shaved by 6.4 μm on k sheets
However, the shaving amount of the first developing sleeve is 9.9 μm.
U. The toner is adjusted by adjusting the gap between the developing sleeves.
Although the supply amount (M / S) could be kept constant,
(Q / M) x toner supply amount (M /
S) shows different values. This is the tribo (Q
/ M). On the other hand, in this embodiment, Table 4
The above problem is solved by adopting the configuration shown
Was. [0052] The formulation of the membrane is as shown in Table 5. Resin (B) and Pygme
(P) weight ratio P / B
Set large. By the way, the ratio of graphite to carbon is
9: 1 is preferable from the dispersibility of carbon. [0053]Table 4 shows the effects of the above configuration. First, the shaving amount of 500k sheets is determined by the second current.
While the image sleeve is 6.4 μm,
The diameter was almost the same as 6.6 μm. This is shown in FIG.
This is because they have the properties shown in FIG. That is, FIG.
The relationship between the P / B ratio and the shaving amount of the film is shown.
When it gets smaller, the film becomes easier to scrape
I applied the characteristic that becomes. Next, regarding the tribo (Q / M), the second current
The image sleeve is regulated by the first developing sleeve and
The image sleeve is opposite to the toner advance direction at the toner regulating section.
Of the first and second developments caused by rotation in the opposite directions
(Q / M) differences were 10.2 and 10.5 μC / g, respectively.
Could be on the order. This is the P / B ratio shown in FIG.
And the tribo (Q / M), P / B
As the ratio increases, the tribo (Q / M) decreases and P /
Characteristics that tribo (Q / M) increases when B ratio is reduced
It is a thing using. As a result, FIG.
VD curve with development characteristics as shown (at 30k sheets)
However, as shown in FIG.
We were able to. As a result, the gradation of the image and the gradation
Qualitative control is possible and the durability of the developing sleeve
The service life can be standardized. By configuring as described above, high speed
The first purpose is to be a compact development system for
In a developing device having a plurality of developing sleeves,
It is possible to prevent the developing property from being different for each developing sleeve,
Recent digital images and images compatible with graphics
It can meet the requirements of gradation and gradation stability,
Developing device having a plurality of developing sleeves as a second object
, The life of the developing sleeve can be shared.
To reduce the maintenance work of service personnel.
Service cost can be reduced
High-density and stable developing equipment with no rust image
Could be provided. <Embodiment 2> Next, an embodiment of the present invention will be described.
State 2 will be described. Embodiment 1 of the image forming apparatus according to the present invention
Is the same as The feature of this embodiment is that it is harder to
By using a highly conductive material, the developing sleeve
The point is that the diameter has been further reduced to save space.
You. The developing device 2 used in the present embodiment
explain in detail. As a developer, a one-component magnetic toner of negative polarity
Was used. As shown in FIG. 1, the developing device 2 has two developing switches.
Leaves 20 and 30, and the first developing sleeve 20
Of aluminum A2017 of φ20mm which is a magnetic member
After blasting with FGB # 600 above,
It is configured to perform. Also, the second developing sleeve
30 is also a non-magnetic member made of aluminum of φ20 mm.
Blast processing with FGB # 600 on
It is constructed by coating. The coating is
Prevents sleeve ghost images that occur in the sleeve cycle
And to increase the durability of the sleeve surface
You. The first developing sleeve 20 is attached to the photosensitive drum 1
It rotates at a speed of 150%. Toner is magnetic
The thickness of the layer is regulated by the gap 20A, and the S-Bgap is 250
It is set to μm. First developing sleeve 20 and photosensitive
The distance S-Dgap from the drum 1 was 230 μm,
Leave 20 has a DC bias of + 200V and is shown in FIG.
Like this, a rectangular wave with Vpp of 1400V and frequency of 2.7kHz
Performs magnetic one-component non-contact development applied as an AC bias.
U. Therefore, the development contrast is 300 V in the flight direction,
The fog removal contrast becomes 100V. As the second developing sleeve 30, a non-magnetic portion
Formed on aluminum A2017 of φ20mm
What has been used is used. This developing sleeve 30 has +
200V DC bias and Vpp140 as shown in FIG.
A rectangular wave of 0 V and a frequency of 2.7 kHz is applied.
Since the application means is the same as the first developing sleeve 20,
And reduced costs because only one power source is needed.
And reduced power supply space
There is. The developing sleeve 30 is 15
Rotate at 0% speed. The developing sleeve 30 and the photosensitive drum
The distance S-Dgap from 1 is set to 230 μm. still,
The magnetic blade 20A is the same as in the first embodiment. Next, the features of this embodiment will be described.
You. The material used in the present embodiment is a resin (B)
Epoxy resin and TiO as pigment (P)_Two When
Carbon was used. This film is different from the film used in the first embodiment.
With high durability and chargeability against negative charging
There are high features. The results of using this material are shown below.
You. Table 6 shows the film formulation, amount of shaving, and triboelectricity in the conventional system.
(Q / M), toner supply amount (M / S) and tribo (Q / M
M) × Toner supply amount (M / S). [0067] [Table 6] As can be seen from Table 6, in the conventional system, 500
While 6.8 μm of the second developing sleeve is cut on k sheets
The first developing sleeve is shaved by 10.0 μm.
The overall value is larger than in the case of state 1 because the sleeve diameter is
Because it has become smaller). And with the index of development characteristics
A certain toner supply amount (M / S) x tribo (Q / M)
Shows different values. On the other hand, in the present embodiment, Table 7
The above problem is solved by adopting the configuration shown
Was. [0070] The formulation of the membrane is as shown in Table 8. Resin (B) and Pygme
(P) weight ratio P / B is the developing sleeve speed
The faster one was set smaller than the slower one. By the way,
TiO_Two And the ratio of carbon to carbon is 9: 1 due to the dispersibility of carbon.
Is preferred. [0071] Table 7 shows the effects of such a configuration. First, the shaving amount for 500k sheets is the second current value.
While the image sleeve is 6.8 μm,
The diameter was almost the same as 6.9 μm. This is three
Meaning that it was not cut even though the diameter was reduced
I do. Similarly, as the P / B ratio increases, the film becomes easier to scrape.
Conversely, if the P / B ratio is reduced,
Applied. Next, regarding the tribo (Q / M),
The image sleeve is regulated by the first developing sleeve.
In addition, the first developing sleeve is provided with a toner regulating section for controlling the progress of toner.
Developing sleeve caused by rotation in the opposite direction
The difference between the tribo (Q / M) of the
0.9, 11.1 μC / g
Was. This corresponds to the P / B ratio and Q / M (30 k) shown in FIG.
As is clear from the relationship, when the P / B ratio is increased,
When the ribo (Q / M) decreases and the P / B ratio decreases,
It utilizes the property of increasing tribo (Q / M).
You. By doing so, it is an index of development characteristics
Tribo (Q / M) × Toner supply amount (M / S)
Can be equalized, and as a result,
VD curves could be made substantially the same. This
Control of image gradation and gradation stability
Not only is possible, but also the durable life can be shared.
And development by selecting such materials
Space saving of the device 2 has become possible. With the above configuration, high
The development system is compatible with high-speed machines.
A small developing device having a plurality of developing sleeves
Therefore, it is possible to prevent the developing property from being different for each developing sleeve.
Images compatible with recent digital images and graphics
It can meet the requirements of image gradation and gradation stability,
Further, a second object of the present invention is to provide a developing device having a plurality of developing sleeves.
In the device, the life of the developing sleeve can be shared.
And eliminate the need for maintenance for service personnel.
Service costs can be reduced, and high
A stable developing device could be provided. The third object, ie, high speed operation, is
Is stable at a high concentration and can save space.
A developing device having a life of 100,000 sheets could be provided. <Embodiment 3> Next, an embodiment of the present invention will be described.
State 3 will be described. This embodiment is characterized by a reuse image forming apparatus.
That is, the developing device according to the present invention is applied to the apparatus. The reuse system is basically not transferred but remains.
Cleaning is waste toner.
Tribo is extremely small compared to New toner
And the cohesion of waste toner increases,
The share of S-Bgap increases, and the amount of film shaving increases.
This is shown in the developing characteristics of the reuse system shown in FIG.
You. The overall density is lower than that of the new toner.
And the difference between the developing sleeves is larger
You. This embodiment has been implemented in view of the above.
It is. In the present embodiment, the image formation shown in FIG.
A-Si drum was used as the photosensitive drum 201 in the apparatus
The digital copying machine will be described. The process speed of the digital copying machine is 57
0 mm / s at 110 sheets / min.
The surface is uniformly charged to +500 V by the primary charger 203
You. Next, 600 nm with a semiconductor laser having a wavelength of 680 μm.
Exposure 212 by PWM at the dpi
1 to form an electrostatic latent image. Next, regular development is performed by the developing device 202.
The electrostatic latent image is visualized as a toner image. Magnetic as developer
Jumping development using a neutral one-component negative toner. G
The particle size of the toner is 6.0 μm. With a conventional two-component developer
A service person must replace the carrier every 100,000
Is not maintenance-free.
The benefits cannot be reflected much. On the other hand, durability is ignored
Uses dry magnetic one-component toner that requires no maintenance
Was. The developing bias is 2400 Hz, 1 for both the first and second.
500Vpp, Duty 50% AC voltage + 200V DC
A bias voltage on which a voltage is superimposed is applied. S-Bgap is
Both were 250 μm, and S-Dgap was 250 μm. That
Then, a total current of -200 μA is passed through the post charger 210.
After charging the toner image, the toner
Image is transferred by the transfer charger 204, and the toner image is transferred.
The transferred transfer material is sent to the fixing device 207 to define the toner image.
To wear. On the other hand, the transfer residual toner on the photosensitive drum 201
Is removed and collected by the cleaning device 206, and
The waste toner (reuse toner) is developed through
Return to upper 209B. There is no screw inside the transport pipe 208.
A transfer member in the form of a menu is provided.
By rotating, the reused toner is transported. Soshi
And the reused toner is collected in the developing hopper 209B.
And reused. The new toner is stored in the hopper 209A.
And the magnetic force of the magnet rollers 21A and 21B.
And the magnet rollers 21A, 21A
1B is conveyed to the developing device 202 by rotation.
You. In this embodiment, the reuse toner and the new toner
Was mixed in the developing device 202.
It is permissible to provide a mixing space inside the room. Thus, the toner mixed in the developing device 202
The toner is sent to the developing sleeve again, and
Is used for development of the electrostatic latent image formed on the substrate. Magnetro
The normal rotation speed of the roller 21A is 2 revolutions / minute,
The rotation speed of the net roller 21B is changed. Developing device
Self-weight of toner on piezo sensor (made by TDK) in 202
Is not applied, and when the piezo sensor vibrates, the toner
A supply signal is issued. Normally, the magnet roller 21B
Is 10/90 (magnet) with respect to the magnet roller 21A.
Roller 21A: magnet roller 21B = 9: 1)
To Configuration of developing device 202 according to the present embodiment
Is an epoxy resin and TiO, as in the second embodiment._Two ,
Both sleeve diameters are φ20mm with a membrane using carbon.
You. Table 9 shows the effects of the present embodiment. [0087] [Table 9] As shown in Table 9, the amount of shaving on 500k sheets was
While the image sleeve is 7.4 μm,
The diameter was almost the same as 7.3 μm. this isRieux
SLife is about 600k despite the aggregation of waste toner
Means that. Next, the tribo (Q / M) is the developing sleeve speed.
While the faster one is deteriorated by the mechanical share,
The chargeability of the deteriorated toner can be further increased
Was. That is, the tribo (Q / M) of the first developing sleeve is changed to the second
It could be comparable to that of the developing sleeve. this
So that the overall charge is low
In the system, tribo (Q / M) ×
It is possible to make the toner supply amount (M / S) almost equal.
As a result, the VD curve which is the development characteristic is almost
The curves could be almost identical. This allows the image
Control of the gradation and gradation stability of
The realization of a Ulysse system with a common durable life
did it. With the above-described configuration, reuse compatible
Development system, and the first purpose
In a small developing device having a developing sleeve, a developing three
Can be prevented from being different for each
Image gradation and image gradation corresponding to
The requirement of tonal stability can be satisfied, and the second object
In a developing device having a plurality of developing sleeves.
The service life of the image sleeve can be
Service maintenance.
Cost can be reduced, and the stable
An imaging device could be provided. The third object, a sleeve ghost image
There is no
Current and environmentally friendly with reuse
An imaging device could be provided. [0091] As is apparent from the above description, the present invention
According toToner carrierBy sharing a common life span
Eliminates the need for service personnel and reduces service costs
Be able toToner carrierEvery developability
Eliminate the differences to digital images and graphics in recent years
It is necessary to satisfy the requirements for gradation and gradation stability of the corresponding image.
The effect that can be obtained is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a developing device according to the present invention. FIG. 2 is a perspective view of a developing sleeve of the developing device according to the present invention. FIG. 3 is a cross-sectional view of a main part of an image forming apparatus including a developing device according to the present invention. FIG. 4 is a sectional view showing a magnetic pole arrangement of the developing device according to the present invention. FIG. 5 is a sectional view showing a magnetic pole arrangement of the developing device according to the present invention. FIG. 6 is a diagram illustrating a relationship between an arrangement of a developing sleeve of the developing device according to the present invention and a magnetic seal member. FIG. 7 is a diagram showing a developing bias waveform. FIG. 8 is a diagram illustrating development characteristics of a conventional developing device. FIG. 9 is a diagram showing development characteristics of a conventional developing device. FIG. 10 is a diagram showing the relationship between the P / B ratio of the film composition and the amount of film shaving. FIG. 11 is a diagram showing the relationship between the P / B ratio of film composition and tribo (Q / M). FIG. 12 is a diagram showing development characteristics of a conventional reuse image forming apparatus. FIG. 13 is a sectional view of a main part of a reuse image forming apparatus including a developing device according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of an image forming apparatus including a conventional developing device. DESCRIPTION OF SYMBOLS 1 Photosensitive drum (electrostatic latent image carrier) 2 Developing device 3 Primary charger 4 Transfer charger 6 Cleaning device 7 Fixing device 10 Post charger 12 Image exposure 20 First developing sleeve (upstream developing Developer carrier) 30 Second developing sleeve (downstream developer carrier)

Claims (1)

(57) [Claims] 1. An electrostatic latent image carrier is juxtaposed along the rotation direction.
And carry the upstream and downstream toner rotatable in the same direction.
And the toner layer thickness on the toner carrier on the upstream side
Blades, and each toner carrier is constituted by a non-magnetic member around the internal magnetic member and a coating member covering the same, and the layer thickness regulation of the toner on the downstream toner carrier is regulated by the upstream. in <br/> developing device configured to perform the toner carrier side, B the weight of the resin constituting the coating member, a resin
Graphite and conductive carbon mixed with water
If the weight of titanium oxide and conductive carbon is P
Weight ratio of the coating member of the toner carrier on the downstream side
P / B development apparatus, wherein a is larger than the weight <br/> weight ratio P / B of the coating member of the upstream side toner carrying member.