JP2000206776A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of preventing developer carrying force from being lowered and soiling from being caused by toner fusion on the surface of a developing sleeve, even in the case of using an elastic blade and stably obtaining an image without void for a long time. SOLUTION: In this developing device, positively charged magnetic toner being one-component developer is used as developer. The surface of the developing sleeve 2 installed in the developing device is formed so that average inclination Δa is >=0.001 and <=0.1, the toner regulating pole N1 of a magnet 6 in the sleeve 2 is arranged so that the peak of magnetic force may be held in the vicinity of the free end of the elastic blade 3, and further the half-value width of the regulating pole N1 is set to >=20 deg. and <=50 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a laser beam printer, a facsimile, etc. using an electrophotographic system, and more particularly, to a developer carrier used for transporting the developer. It is related to the improvement of.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine using an electrophotographic method, an electrostatic latent image formed on an image carrier is developed by a developing device.

In such a developing device, for example, a metal developing sleeve is used as a developer carrying member, and a developer contained in a developing container is carried on the developing sleeve, and a developing area facing the image carrying member is used. The electrostatic latent image formed on the image carrier is developed with a developer to visualize the latent image.

The developers include a magnetic one-component developer composed of a magnetic toner, a non-magnetic one-component developer composed of a non-magnetic toner, and a two-component developer composed of a non-magnetic toner and a magnetic carrier. The material of the developing sleeve is selected depending on the developing sleeve.

In the case of jumping development using a magnetic one-component developer, that is, a magnetic toner, the developing sleeve is made of SUS.
A magnetic generating means such as a magnet is provided in the developing sleeve. During development,
In order to perform good development, a development bias is applied to the development sleeve. AC voltage,
A voltage obtained by superimposing both DC voltages is used.

[0006] In the above-described developing apparatus, for example, as disclosed in Japanese Patent Application Laid-Open No. 56-113172, the surface of the developing sleeve is roughened to transfer the magnetic toner on the developing sleeve to the developing area. The transportability at the time of transport is improved, and a uniform toner layer can be coated on the surface of the developing sleeve.

As a method for roughening the surface of the developing sleeve,
A sandpaper method in which the surface of the developing sleeve is rubbed with sandpaper, a bead blast method using spherical particles, a sandblast method using irregular particles, a mixture method thereof, and a chemical etching method by chemical treatment have been proposed and implemented.

[0008]

However, the conventional developing sleeve has the following problems.

In the developing sleeve roughened by the above-mentioned various methods, the toner or the components in the toner adhere to the roughened surface of the roughened surface due to long-term use, and are easily fused to each other. Be contaminated.

The toner on the developing sleeve originally obtains electric charge by frictionally charging with the surface of the developing sleeve. However, when toner contamination on the surface of the developing sleeve occurs, the toner on the developing sleeve is fused to the surface. Because of friction with the toner itself, the toner is hardly charged or charged to the opposite polarity. In this case, the triboelectric charge (triboelectric charge) of the toner does not increase, so that the image density decreases. In particular, when the toner is fused to a specific part of the surface of the developing sleeve, the image density is reduced only at that portion, resulting in an uneven image.

Further, when contamination with toner progresses with an increase in use, phenomena such as white spots occur in the obtained image in the rotation cycle of the developing sleeve. As an example, FIG. 19 shows a solid image in which unevenness due to a periodic white spot has occurred. When the contact method such as an elastic blade is regulated, although there is an advantage that a high triboelectric charge is high and high image quality is easily obtained, the toner is mechanically controlled because the elastic blade and the developing sleeve surface contact to regulate the toner. Such white spots and the like are particularly remarkable because they are easily pressed by the developing sleeve and are likely to receive a shearing force.

In order to prevent such an image defect,
It is necessary to use a developing sleeve having a surface shape to which the toner is not easily fused. The parameters generally representing the surface shape include a center line average roughness Ra and a ten-point average roughness R.
There is z. Various abrasive grains FGB, ARD + FGB, ARD
20 and 21 show the results of examining the effect of these parameters on the image density by a blast method that wants to use a method such as
Shown in

In FIGS. 20 to 21, the density difference ΔD on the vertical axis is shown.
Is the difference between the initial density of the image and the density after 10,000 copies, and ΔD
The larger the value, the greater the decrease in image density due to long-term use. As can be seen from FIGS. 20 and 21, the conventional parameters Ra and Rz could not be correlated with toner contamination (toner fusion) of the developing sleeve.

As a method for preventing or reducing the toner contamination, it is desired to make the surface of the developing sleeve smoother. However, if the surface is made smoother, the toner transportability is reduced, and the developing sleeve is not sufficiently developed. It was difficult to supply toner. Further, the toner is charged up, and a ghost occurs in the image in the rotation cycle of the developing sleeve.

As a method for solving these problems,
As described in JP-A-2-64561 and JP-A-2-284163, there is a method in which irregularities due to a plurality of spherical trace dents are formed on the surface of a developing sleeve by a blast treatment with regular particles.

By performing this surface treatment on the developing sleeve, in a non-contact developer regulating system using a magnetic blade, toner fusion on the developing sleeve surface can be slightly reduced, and at the same time, a uniform toner layer is formed on the developing sleeve. Can be coated. However, even with this surface treatment, the development sleeve in the contact regulation system using the elastic blade does not sufficiently prevent the fusion of the toner on the surface,
There were still points that were not satisfactory, such as the appearance of sleeve ghosts.

Therefore, although the developing device of the developer regulating type using the elastic blade has an advantage that high image quality can be easily obtained, it is possible to reduce the conveying force of the magnetic toner, to prevent the fusion of the toner on the surface of the developing sleeve, and to make the image white. It was an issue to achieve both prevention of missing (white streaks).

An object of the present invention is to obtain an image which is stable for a long period of time without a decrease in developer conveyance force and no contamination due to toner fusion on the surface of a developing sleeve even when an elastic blade is used. It is an object of the present invention to provide a developing device which is enabled.

[0019]

The above object is achieved by a developing apparatus according to the present invention. In summary, the present invention provides:
The developer is carried on a rotating developer carrier having a magnet on the inside, and the layer thickness of the developer carried on the developer carrier is regulated by an elastic regulating member in contact with the developer carrier, and the development is performed. A developing device for developing the electrostatic latent image formed on the image carrier with the developer conveyed to a developing unit facing the image carrier by the rotation of the developer carrier; Wherein the average inclination Δa is 0.001 or more and 0.1 or less, and the magnet is provided with a magnetic pole having a magnetic force peak near the free end of the elastic regulating member. It is.

According to the present invention, the half width of the magnetic pole is 20
It is set to be not less than {not more than 50}. By performing a roughening treatment on the surface of the developer carrying member, the average inclination Δa is set to 0.0
It can be adjusted to a range from 01 to 0.1. Further, the surface of the developer carrying member is subjected to a surface roughening treatment and a resin layer containing crystalline graphite and conductive carbon is coated thereon, or a Ni-P plating layer or Ni-B By coating a plating layer or a Cr plating layer, the average slope Δa can be adjusted to 0.001 or more and 0.1 or less. The material of the developer carrier may be stainless steel or aluminum, and the developer may be a magnetic one-component developer that is positively charged.

According to another aspect of the present invention, a developer is carried on a developer carrier, and the layer thickness of the developer carried on the developer carrier is regulated by a regulating member. In a developing device for supplying the developer conveyed to the developing section facing the image carrier by movement to develop an electrostatic latent image formed on the image carrier, the surface of the developer carrier has an average inclination Δa Is not less than 0.001 and not more than 0.1, and the center line average roughness Ra is not less than 0.3 μm and not more than 3 μm.

According to the present invention, the surface of the developer carrying member is polished with diamond, blasted, and a resin layer containing crystalline graphite and conductive carbon is coated thereon, or Ni is coated thereon. -P plating layer, Ni-B plating layer, or Cr plating layer, the average inclination Δa
Can be adjusted to 0.001 or more and 0.1 or less, and the center line average roughness Ra can be adjusted to 0.3 μm or more and 3 μm or less. The material of the developer carrier is aluminum, and the developer is a magnetic one-component developer, a non-magnetic one-component developer, or a two-component developer. The regulating member may be an elastic regulating member or a magnetic regulating member, and the material of the developer carrier may be aluminum.

In still another embodiment of the present invention, a developer is carried on a rotating developer carrier having a magnet on the inside, and the layer thickness of the developer carried on the developer carrier is measured. The developer conveyed to the developing section opposed to the image carrier by the rotation of the developer carrier is regulated by the elastic regulating member in contact with the body, and the developer is developed into an electrostatic latent image formed on the image carrier. In the developing device, the surface of the developer bearing member has an average inclination Δa of 0.001 or more and 0.1 or less, and the relationship between the center line depth Rp and the center line height Rv of the surface roughness is Rp <Rv. A developing device characterized in that the developing device is formed as follows.

According to the present invention, the surface of the developer carrying member is polished with diamond, blasted, and a resin layer containing crystalline graphite and conductive carbon is coated thereon, or Ni is coated thereon. −P
By coating a plating layer, a Ni-B plating layer, or a Cr plating layer, the average inclination Δ
When a is 0.001 or more and 0.1 or less, the relationship between the center line depth Rp and the center line height Rv of the surface roughness can be adjusted to Rp <Rv. After the coating of the resin layer, the relationship between the average inclination Δa and the center line depth Rp and the center line height Rv can be adjusted by further performing polishing with a wrapping tape. The developer is a magnetic one-component developer or a non-magnetic one-component developer.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a sectional view showing an embodiment of the developing device of the present invention. This developing apparatus employs a jumping development method using a magnetic toner of a magnetic one-component developer. An image forming apparatus using this developing apparatus has a process speed of 300.
It is an analog device having a performance of 60 mm / sec.

The developing device includes a developing container 7 containing a magnetic toner, and a photosensitive drum (image carrier) 1 of the developing container 7.
A developing sleeve (developer carrying member) 2 having a diameter of 20 mm. The developing sleeve 2 carries the magnetic toner and conveys it to the photosensitive drum 1, and imparts a triboelectric charge appropriate for developing the latent image. Developing sleeve 2
Inside, a roller-shaped permanent magnet 6 having four magnetic poles is arranged. An electromagnet can be used as the magnet.

On the upper part of the developing sleeve 2, an elastic blade (elastic regulating member) 3 is disposed as a developer regulating member. The elastic blade 3 is formed by laminating a silicone rubber plate having a thickness of 0.35 mm and a SUS plate having a thickness of 0.05 mm so as to be integrally formed to have a total thickness of 0.4 mm. Sleeve 2 and contact pressure 15g / cm
Is in contact with. With this elastic blade 3, the magnetic toner carried on the developing sleeve 2 is formed in a thin layer, and a triboelectric charge is applied to the toner.

The inside of the developing container 7 is divided into two chambers, and each chamber has a first stirring member 4,
A second stirring member 5 is provided, and performs stirring of the toner and conveyance of the toner to the developing sleeve 2.

In this embodiment, a positively charged toner is used as the magnetic toner.
Is made of SUS, and its surface is made uneven so as to impart a toner conveying force. However, as described in the conventional example, in a roughened developing sleeve, toner or a component in the toner easily adheres and fuses to the uneven portion of the roughened surface, and the surface is contaminated.

Microscopic photographs of the surface of the developing sleeve without toner contamination and the surface with toner contamination are shown in FIG.
(A) and (b) show. As can be seen from comparison with FIG. 2A, in the contaminated surface portion shown in FIG. 2B, the toner is fused in black at the concave portion of the surface. It was confirmed that the density of the image portion corresponding to the contaminated portion of the developing sleeve was reduced by 0.5 compared to the image portion corresponding to the portion having no contamination. From this, it can be understood that the toner is fused to the surface of the developing sleeve and contaminated, which causes an image defect.

For some SUS developing sleeves, irregular alumina particles (ARD) or spherical glass beads (FGB) are used as abrasive grains, and blasting is performed while changing the blast pressure to roughen the surface. And surface roughness were measured.

For the measurement of the surface roughness, a contact type surface roughness meter (manufactured by Kosaka Laboratory Co., Ltd .: Surfcoder SE-330)
0) was used. This measuring instrument provides Δa, R
a and Rz can be measured simultaneously. The measurement conditions are
The cut-off value is 0.8 mm, the measurement length is 2.5 mm, the feed speed is 0.1 mm / sec, and the magnification is 5000 times.

By comparing this surface roughness information with the degree of toner contamination of the developing sleeve after 10,000 sheets of long-term use, the level of contamination can be determined by the average slope Δa of the developing sleeve surface.
And that the smaller the value of Δa, the lower the value. That is, the toner contamination on the developing sleeve surface is not the magnitude of the surface roughness represented by Ra and Rz,
This is largely due to the surface shape of the developing sleeve.

Here, the average inclination Δa is given by the equation of FIG. Qualitatively, the slope of the roughness curve in FIG.
Represents The significance of this Δa is as follows from the various wavy curves shown in FIGS. 4A to 4C in the wavy curve A of FIG.
4C is different from the slope of the wavy curve C in FIG. 4C. The slope of the curve C in FIG. 4C having a small value of Δa causes less toner adhesion to the developing sleeve. Also, the image density is high.

This is because the smaller the inclination of the surface roughness is microscopically, the less the toner is caught on the surface of the developing sleeve,
This is considered to be due to no adhesion. From this, it is possible to reduce the level of toner contamination on the surface of the developing sleeve by reducing the average inclination Δa.

FIG. 5 shows that the abrasive grains are FGB, ARD, FGB +
The graph shows the relationship between the average inclination Δa and the density difference ΔD between the initial stage of image formation and after long-term use, that is, the decrease in density, for a developing sleeve subjected to blast processing with some changes to ARD. From this graph, it was found that the value of Δa on the developing sleeve surface was about 0.1
It is possible to keep the contamination level low by processing as follows.

More specifically, the surface of a SUS developing sleeve is treated with an amorphous alumina particle (ARD) No. 400 at a blast pressure of 4.0 kg / cm ² , and then a spherical glass bead (FGB) 300 Blast pressure 3.0kg /
cm ² , and finally with an FGB No. 600 at a blast pressure of 3.0 kg / cm ² to obtain an average slope Δ
a could be reduced to 0.1 or less.

However, if the average inclination Δa is set to 0.1 or less, the toner conveyance force is extremely reduced, and a problem occurs that a sufficient amount of toner cannot be conveyed to the developing area. This embodiment is characterized in that Δa is set to 0.1 or less and, as shown below, a high-quality image without developing sleeve contamination and toner transportability is obtained by optimally combining magnetic field patterns. Can be provided.

As described above, 4
A magnet 6 having two magnetic poles is arranged, and each magnetic pole has a magnetic force of about several hundred to several thousand gauss (G). In this example, four poles are used, but any of six poles and eight poles may be used, and the effect is the same.

FIG. 6 shows a general arrangement of magnetic poles of the magnet 6 in a conventional developing device of the toner regulating system using an elastic blade. The magnetic pole S1 of the magnet 6 is a pole related to development, and is disposed at a position facing the photosensitive drum 1. The magnetic pole N1 is a pole that regulates the layer thickness of the toner.
And the magnetic poles S2 and N2 are the poles for carrying the toner, and are disposed substantially opposite to the magnetic poles S1 and N1, respectively. Table 1 shows the magnetic flux density and position of each magnetic pole.
Shown in

[0042]

[Table 1] According to the study by the present inventors, it has been clarified that the toner contamination level of the developing sleeve greatly changes and the toner conveyance amount also changes depending on the arrangement position of the toner regulating pole N1 among these magnetic poles. All the developing sleeves used here were made of SUS, and the surface was subjected to the above-described processing.

Regarding the position of the toner regulating pole N1 (defined by the peak position of the magnetic force of the magnetic pole N1), several modes shown in FIG. 7 were examined. That is, in the rotation direction of the developing sleeve 2,
The downstream side (FIG. 7A), 20 ° downstream (FIG. 7B) of the toner regulating portion (the contact portion between the elastic blade 3 and the developing sleeve 2), the regulating portion (opposite) (FIG. 7C) )), Near the free end of the elastic blade 3 (10 ° upstream to 10 ° downstream of the free end) (FIG. 7D), 20 ° upstream of the free end (FIG. 7D).
(E)). Table 2 shows the results.

[0044]

[Table 2] As shown in Table 2, the toner coating amount M on the developing sleeve
/ S is maximized when it is arranged near the free end of the elastic blade 3 so as to have a magnetic force peak position of the regulating pole N1.
Also, the contamination level on the surface of the developing sleeve is minimized when the magnetic force peak position of the regulating pole N1 is arranged near the free end of the elastic blade 3 and the image density is maximized even if the magnetic force peak position is arranged on the upstream side of the toner regulating section. I understood that.

Table 3 shows the magnetic flux densities and positions of the respective magnetic poles when the regulating pole N1 is arranged near the free end.

[0046]

[Table 3] As for the cause of the blank image (streak), when the regulating pole N1 was disposed in the toner regulating portion, as shown in Table 2, the streak-like unevenness of the toner on the developing sleeve occurred. This is because the toner is attracted to the magnetic pole N <b> 1 in the regulating portion, and the toner is clogged in the nip of the regulating portion.

The difference in the degree of contamination of the developing sleeve depending on the position of the regulating pole N1 is due to the difference in the flow of toner. FIG. 8 shows the result of observing the movement of the toner near the elastic blade 3 with a microscope.

As shown in FIG. 8A, when the regulating pole N1 is disposed downstream of the toner regulating section (contact section) where the developing sleeve 2 and the elastic blade 3 contact each other, the developing sleeve 2
In addition to the toner conveyed in the circumferential direction, the toner falling from the upper portion together flows into the regulating portion, and the toner density increases. FIG.
When the regulating pole N1 is opposed to the toner regulating section as shown in (b), only the toner conveyed in the circumferential direction of the developing sleeve 2 enters the regulating section, and the upper toner stays.

As shown in FIG. 8 (c), when the regulating pole N1 is arranged near the free end of the elastic blade 3 on the upstream side of the regulating section (10 ° upstream to 10 ° downstream of the free end), The flow is such that the toner layer is divided into two parts in the foreground, and only the toner in the lower layer enters the regulating part. This is because the presence of a magnetic force near the free end of the elastic blade 3 causes the magnetic toner to rise and the volume of the toner layer to increase. As a result, the density of the toner layer decreases before the elastic blade nip, and passes through the nip portion in this state, so that the degree of freedom of movement of the toner is increased as compared with the case where the regulating pole N1 is disposed downstream ( (Not pressed by the nip), thereby reducing the shearing force of the toner on the surface of the developing sleeve. This is the reason why toner contamination of the developing sleeve can be reduced.

As shown in FIG. 8D, if the regulating pole N1 is disposed further upstream, although the toner is once conveyed by the magnetic pole N1, there is no magnetic pole from the free end of the elastic blade 3 to the contact portion. , Approaching the state arranged downstream.

Table 4 shows the toner density between the free end of the elastic blade and the contact portion when the position of the regulating pole N1 is changed.
Toner coating amount M / S when the position of magnetic pole N1 is changed
Is as described above (Table 2).

[0052]

[Table 4] Here, the reason why the toner coating amount can be increased when the magnetic force of the regulating pole N1 is near the free end of the elastic blade 3 is that the peak of the regulating pole N1 is near the free end, so that the toner magnetic brush This seems to be due to the fact that the ears are hardened and the hardened ears act to push up the end of the elastic blade 3.

Regarding the peak position of the regulating pole N1 with respect to the free end of the elastic blade 3, that is, the arrangement position of the regulating pole N1, both the toner contamination of the developing sleeve and the toner coating amount are about 15 ° to the downstream side of the upstream side of the free end. The effect is significant at about 15 ° on the side, and the effect is particularly large at less than 10 ° on the upstream side and the downstream side. Therefore, in this embodiment, this range is set to a position near the free end of the elastic blade 3 with respect to the arrangement of the regulating pole N1.

Therefore, the decrease in the amount of toner transported by reducing the average inclination Δa of the developing sleeve 2 is caused by the fact that the peak position of the magnetic force of the regulating pole N1 is located near the free end of the elastic blade 3 as in this embodiment. By doing so, it is possible to increase the amount of toner coating, prevent contamination of the developing sleeve, and secure the amount of toner required for development.

FIG. 9 shows the relationship between the average inclination Δa of the developing sleeve and the toner coating amount M / S. In the figure, the shaded area is a region where both the toner coating amount and the developing sleeve contamination are at a preferable level. Incidentally, the standard of the amount of toner necessary for development is 0.85 mg / cm ² or more.

Conversely, if the amount of toner coating increases but the amount of triboelectric charge of the toner decreases, the development efficiency decreases and the density of the image decreases. FIG.
Amount of toner, development sleeve contamination, and triboelectric charge (density) when the position of the regulating pole N1 is changed
Are indicated by oblique lines.

This region is a region where Δa is set to 0.1 or less and the regulating pole N1 is set near the free end of the elastic blade 3. By setting the Δa on the surface of the developing sleeve to 0.1 or less, the charge amount Q / M of the toner is reduced to 10.0.
μC / g or more, and good image density was maintained. This shows the same tendency even when the contact pressure of the elastic blade with the developing sleeve is changed.

As described above, the flow of the toner varies greatly depending on the position of the regulating pole N1, which causes the load on the developing sleeve and the amount of toner transported by the developing sleeve to change. However, if Δa is less than 0.001,
The toner charge amount Q / M becomes too high, and conversely, the image density decreases.

If the half width of the regulating pole N1 is too wide, the effect of changing the position of the magnetic pole is reduced. Therefore, the half width of the regulating pole N1 is set to 50 ° or less. Table 5 shows the toner coating amount and the level of development sleeve contamination prevention when the half width of the regulating pole N1 is variously changed.

[0060]

[Table 5] As shown in Table 5, as the half width of the regulating pole N1 is reduced, the amount of toner coating increases, and the prevention of contamination of the developing sleeve tends to be improved.
゜ By setting the value to the following, the developing sleeve can be kept in a good state without contamination. However, if the half width is less than 20 °, a sufficient toner regulating force cannot be obtained, and a toner layer having a stable layer thickness cannot be formed.

As described above, in this embodiment, the surface of the developing sleeve of the developing device has an average inclination Δa of 0.00
The toner regulating pole N1 of the magnet in the developing sleeve is formed so as to have a magnetic force peak near the free end of the elastic blade, and the half width of the regulating pole is further reduced. Since the angle is set to 20 ° or more and 50 ° or less, contamination due to fusion of the toner on the surface of the developing sleeve can be significantly improved, and further, the toner conveying force does not decrease. However, a sufficiently high-quality image could be stably obtained over a long period of time.

Embodiment 2 This embodiment is different from the embodiment 1 shown in FIG. 1 in that after the surface of the developing sleeve 2 is roughened, a resin layer containing crystalline graphite and conductive carbon is coated thereon. By doing so, the surface of the developing sleeve 2 is characterized in that the average inclination Δa is formed to be 0.001 or more and 0.1 or less.

In this embodiment, a silicone rubber plate having a thickness of 0.35 mm and a thickness of 0.05 mm
And a SUS plate is bonded, and an elastic blade 3 integrally molded to a total thickness of 0.4 mm is used. The elastic blade 3 is brought into contact with the developing sleeve 2 at a contact pressure of 12 g / cm to form a developing sleeve. 2 to form a thin layer of the magnetic toner and to apply a triboelectric charge to the toner. Similarly, the development is performed by a jumping development method using a positively charged magnetic toner.

When the surface of the developing sleeve 2 is coated with a resin layer, the average inclination Δa can be easily controlled within the range of 0.001 to 0.1, and the wear resistance of the surface of the developing sleeve 2 is improved. There is also an effect of suppressing generation of a ghost image.

When aluminum is used as the material of the developing sleeve 2, although the cost can be reduced as compared with stainless steel, the wear resistance of the developing sleeve surface is reduced, and the life of the developing sleeve is shortened. Even if this is coated with a resin layer on the surface even with an aluminum developing sleeve,
The surface hardness is higher than that of aluminum, and the life of the developing sleeve can be extended.

In a document in which an image portion having a black portion (character) in a white background portion exists in the front in the developing direction, and a halftone image portion follows the image portion, the halftone portion of the developed image has Traces of characters on the front side in the developing direction (ghost)
However, a phenomenon that occurs in the cycle of the developing sleeve is known. This ghost is caused by the selective development of the toner on the surface of the developing sleeve and the charge-up of the toner. By coating the resin layer on the surface of the developing sleeve, the ghost can be suppressed.

In this embodiment, the average inclination Δ
a is not less than 0.001 and not more than 0.1, and the half width is 20
The arrangement of the magnetic pole N1 of not less than ゜ and not more than 50 ゜ so as to have a magnetic force peak near the free end of the elastic blade 3 for regulating the toner is the same as in the first embodiment.
As described above, the average inclination Δa of 0.001 to 0.
A value of 1 was obtained with the resin layer coated on the roughened surface of the developing sleeve.

One of the purposes of coating the resin layer is to improve the abrasion resistance of the surface of the developing sleeve 2 as described above. This will be further described.

When an a-Si drum is used as a photosensitive drum of a high-speed machine, a heater is provided in the a-Si drum for the purpose of preventing an image flowing phenomenon at first use in the morning. If the developing sleeve is made of stainless steel, it is easily deformed by the heat of the drum heater because of its low thermal conductivity. In order to avoid thermal deformation due to the drum heater, aluminum having a high thermal conductivity may be used for the developing sleeve, but aluminum has lower abrasion resistance than stainless steel. If the surface of the aluminum developing sleeve is coated with a resin layer, the surface is hardened and the wear resistance can be easily improved.

Another purpose of the coating of the resin layer is to suppress generation of a ghost image. The generation of the ghost is caused by the selective development of the toner on the surface of the developing sleeve and the toner as described above. Due to charge-up. Therefore, when the toner is negatively charged, by coating a phenol resin or a silicone resin containing crystalline graphite and conductive carbon black, when the toner is positively charged,
Ghost generation can be suppressed by coating a polycarbonate resin instead of a phenol resin or a silicone resin.

In the present embodiment, the surface of the developing sleeve 2 was blasted, and a resin layer in which a phenol resin, conductive carbon and crystalline graphite were blended in a weight ratio of 100: 5: 45 was formed thereon. The thickness of this resin layer was 25 μm for adjusting the average inclination Δa. The blast processing was performed only once using # 600 of FGB.

Average slope Δa due to coating of resin layer
Table 6 shows the results of examining the change in the value of.

[0073]

[Table 6] As shown in Table 6, the value of the average slope Δa depends on the thickness of the coated resin layer, and the larger the thickness, the smaller the value of Δa. This is considered to be due to the effect of filling the unevenness of the roughened surface with the coating resin and smoothing the surface. As described above, by coating the resin layer, the value of Δa can be easily controlled by the film thickness, and the number of blasting processes performed on the base can be reduced.

As described above, in this embodiment, the surface of the developing sleeve is coated with the resin layer containing graphite or the like.
It can be easily formed so that a is 0.001 or more and 0.1 or less. As in the first embodiment, the average inclination Δa of the developing sleeve and the half width of the magnet in the developing sleeve are 20 ° or more and 50 ° or more.
配置 By arranging the toner regulating pole N1 below in the vicinity of the free end of the elastic blade, contamination of the developing sleeve surface due to toner fusion can be significantly improved without lowering the toner conveying force. A high-quality image with sufficient density without any omission was stably obtained over a long period of time. Further, since the resin layer was coated, the abrasion resistance of the developing sleeve surface was improved, and the effect of preventing ghost images was also improved.

Example 3 In this example, as in Examples 1 and 2, a silicone rubber plate (thickness 0.35 mm) and a SUS plate (thickness 0.05 mm) were used.
An elastic blade 3 (0.4 mm in total thickness) integrally formed by laminating the developing sleeve 2 and the developing sleeve 2 was brought into contact with each other at a pressure of 12 g / cm
To form a thin layer of magnetic toner on the developing sleeve 2 and to apply a triboelectric charge to the toner. Similarly, the development is performed by a jumping development method using a positively charged magnetic toner. Further, the toner regulating pole N1 having a half width of 20 ° or more and 50 ° or less is arranged near the free end of the elastic blade 3 so as to have a magnetic force peak.

As in the case of the second embodiment, the surface of the developing sleeve 2 is subjected to a surface roughening treatment, and then a coating is applied thereon to obtain a desired surface shape having an average inclination Δa of 0.001 or more and 0.01 or less. However, this embodiment is different in that Ni-P plating, Ni-B plating, or Cr plating is applied.

The Ni—P, NB, and Cr platings are intended to harden the surface of the developing sleeve 2, suppress the generation of ghost images, and control Δa, similarly to the resin coat of the second embodiment.

As described in the second embodiment, when the material of the developing sleeve is aluminum, the wear resistance is inferior to that of stainless steel. Therefore, it is not possible to apply each plating of Ni-P, Ni-B, and Cr. This is effective for improving the wear resistance of the aluminum developing sleeve. When a positively charged toner is used as the magnetic toner, Ni-P plating can provide an appropriate positive charge to the toner, and is thus effective in preventing ghosting. In particular, the Cr plating has a high positive charge imparting ability and a high hardness, so that the abrasion resistance is more excellent.

Further, for example, Ni-P plating with a P concentration of 8% is performed, and at this time, the value of the average inclination Δa of the developing sleeve can be adjusted by adjusting the thickness of the plating. A surface shape having Δa can be easily formed. In this example, the film thickness of the Ni-P plating is 2
The thickness was 5 μm.

Table 7 shows the results of examining the change in the value of Δa depending on the film thickness of the Ni—P plating.

[0081]

[Table 7] As shown in Table 7, the larger the film thickness of the Ni-P plating, the smaller the value of Δa, and the value of Δa can be controlled by the film thickness of the plating. Similar control is possible for Ni-B and Cr plating.

As described above, in this embodiment, since the surface of the developing sleeve is coated with Ni-P plating, Ni-B plating, or Cr plating, the surface of the developing sleeve has an average inclination Δa of 0. 001 or more.
1 and the elastic blade of the toner regulating pole N1 in which the average inclination Δa of the developing sleeve and the half width of the magnet in the developing sleeve are 20 ° or more and 50 ° or less as in Examples 1 and 2. , Near the free end, can greatly reduce contamination due to toner fusion on the surface of the developing sleeve without causing a decrease in toner transport force. Image could be obtained stably over a long period of time. The plating coating also improved the abrasion resistance of the developing sleeve surface and the effect of preventing ghost images.

Embodiment 4 FIG. 11 is a sectional view showing still another embodiment of the developing device of the present invention. This developing device adopts a jumping developing method using a magnetic toner of a magnetic one-component developer. The image forming apparatus using this developing device has a process speed of 520 mm / sec and an image output of 90 sheets / min. Having.

The developing sleeve 2 installed in the developing container 7 containing the magnetic toner has a diameter of 32 mm. The developing sleeve 2 carries the magnetic toner and conveys it to the photosensitive drum 1, and imparts a triboelectric charge appropriate for developing the latent image. Roller-shaped magnet 6 in developing sleeve 2
Is arranged. In the present embodiment, there is no characteristic in the arrangement of the magnetic poles of the magnet 6, and the magnet 6 may have a general magnetic pole arrangement, for example, four magnetic poles.

In this embodiment, on the upper part of the developing sleeve 2,
As a toner regulating member, a magnetic blade (magnetic regulating member) 8 having a thickness of 1.6 mm is arranged. The magnetic blade 8 is positioned with a gap of 240 μm from the developing sleeve 2, regulates the toner carried on the developing sleeve 2 by a magnetic force in cooperation with the magnet 6, and forms a thin toner layer on the developing sleeve 2. I do. As the toner regulating system, an elastic blade 3 may be used as in the first embodiment shown in FIG.

In the present embodiment, a positively (positive) charged toner is used as the magnetic toner.
Is made of aluminum A6063 having a thickness of 1.0 mm. This embodiment is characterized in that the surface of the developing sleeve 2 is formed so that the average inclination Δa is 0.001 or more and 0.1 or less and the center line average roughness Ra is 0.3 μm or more and 3 μm or less. .

The aluminum sleeve blank is blasted using ARD (amorphous alumina particles), FGB (spherical glass beads), or ARD + FGB as abrasive grains to roughen the surface, or perform diamond polishing. Were blasted to roughen the surface, and several aluminum developing sleeves were prepared, and their surface roughness was measured. In addition, the developing sleeve is subjected to
Ten thousand sheets of images were formed, and the degree of toner contamination on the surface of the developing sleeve was examined. The contamination of the developing sleeve was evaluated by a difference (density reduction amount) ΔD between the initial density of the image and the density after 10,000 copies.

For the measurement of the surface roughness, the above-mentioned contact type surface roughness meter (Surfcoder SE-3 manufactured by Kosaka Laboratory Co., Ltd.) was used.
300) was used. The measurement conditions are as follows:
mm, measuring length 2.5mm, feed speed 0.1m
m / sec, magnification is 5000 times.

By comparing the surface roughness information with the degree of contamination of the developing sleeve after the long-term use of 10,000 sheets,
As shown in FIG. 12, it was found that the contamination level of the aluminum developing sleeve can be reduced by setting the average slope Δa of the developing sleeve surface to 0.1 or less, as shown in FIG. However, if Δa is less than 0.001, the charge amount of the toner becomes too large, and the image density decreases.

Next, Ni-P plating is applied to the surface of the blasted developing sleeve which has been blasted or polished with diamond and then blasted.
The toner was subjected to development using a positively chargeable magnetic toner to form 10,000 images, and the degree of toner contamination of the developing sleeve was examined. The abrasive used for the blasting process is FGB # 600
The blast pressure was 3.0 kg / cm ² . Also Ni
-P plating has a P concentration of 8% and a thickness of 5 μm or 2
It was 0 μm. Table 8 shows the results.

[0091]

[Table 8] As shown in Table 8, the developing sleeve of Comparative Example 1 in which the sleeve tube was blasted and subjected to Ni-P plating with a thickness of 5 μm had an average slope Δa = 0.18 and a contamination level, that is, Sleeve contamination with a density decrease ΔD = 0.43 occurred. As shown in FIGS. 2 (a) and 2 (b), in the contaminated surface portion of the developing sleeve, the toner is fused in black at the concave portion of the surface. It was confirmed that the density of the image portion corresponding to was clearly reduced by 0.43 compared to the image portion corresponding to the portion having no contamination.

On the other hand, a blast treatment was applied to
In the developing sleeve of Comparative Example 2 in which the i-P plating was performed to a thickness of 20 μm, the average slope Δa = 0.07, and the density decrease Δ
The contamination level was reduced to D = 0.17. However, the density decrease ΔD = 0.17 causes toner fusion to a small extent, and in order to maintain the density at 1.2 or more up to 200,000 sheets, which is the useful life of the developing device, this ΔD must be reduced. It needs to be 0.1 or less, which is still insufficient.

In contrast, after cutting the aluminum tube,
Polished with diamond and blasted, 20μm
In the case of the developing sleeve of the present embodiment plated with Ni-P, the average inclination Δa = 0.07 and the density decrease ΔD = 0.0
6 and the contamination level was significantly reduced.

These differences are explained as follows. As shown in FIG. 13 (a), the surface blasted after cutting into the aluminum base tube is finely jagged reflecting the roughness of the surface at the time of cutting. It is undulating,
The toner adheres to the undulation valleys on the surface and becomes stuck in a fused state, so that toner contamination increases.

On the other hand, when the Ni-P plating is performed after the blasting, the improvement is not so large when the film thickness is small, but when the film is relatively thick, the average inclination Δa becomes small, and as shown in FIG. Thus, the surface is slightly jagged, and the overall undulation is loosened. For this reason, it is difficult for the toner to adhere to the undulation valley on the surface and to be in a fused state in which the toner cannot move, and the contamination of the developing sleeve is reduced.

However, in the case of FIG. 13B, the surface is still jagged, so that the toner is caught by the jagged portion, and as described above, the toner is fused to a lesser extent.

On the other hand, in the present embodiment, the diamond is polished after the aluminum pipe is cut, so that as shown in FIG. 14, the jaws at the time of cutting (FIG. 14 (a))
Is almost eliminated by diamond polishing (FIG. 14).
(B)) The surface is modified into a mirror-like surface state without micro-jaggedness even in microscopic view. Thereafter, the surface subjected to the blast treatment and the Ni-P plating is free from fine knurls and deformed by blasting as shown in FIG.
The undulation made gentle by the i-P plating prevents the toner from being caught. As a result, the average slope Δa = 0.
At 07, the contamination level was significantly reduced, with a density decrease ΔD = 0.06.

The surface condition shown in FIG. 13C is difficult to obtain by polishing with another grindstone or sandpaper, and can be easily obtained by performing diamond polishing as in this embodiment. Also in this embodiment, similarly to the third embodiment, Ni-B plating or Cr plating can be used instead of Ni-P plating.

As described above, in the present embodiment, the surface of the developing sleeve made of aluminum has an average inclination Δa of 0.001 to 0.001.
0.1, and at this time, preferably, a series of processing such as diamond polishing, blasting and Ni-P plating, or Ni-B plating, or Cr plating is performed on the surface of the aluminum tube. Control the average inclination Δa to the above-mentioned predetermined value.

By applying these platings, as described above, the surface of the aluminum developing sleeve having poor abrasion resistance can be easily hardened and the abrasion resistance can be improved.
It can be suitably used as a developing sleeve to be combined with an a-Si drum containing a heater. When a positively charged magnetic toner is used as the one-component developer, the above plating can impart an appropriate positive charge to the toner, and is thus effective in preventing ghosting.

In this embodiment, the average inclination Δa is controlled to 0.001 to 0.1 by the surface treatment of the developing sleeve, and at the same time, as described above, the surface roughness (center line average roughness) is controlled.
Ra is controlled to 0.3 to 3 μm.

In order to ensure a certain level of toner conveying force by the developing sleeve, the surface roughness Ra must be increased to some extent. If the surface roughness Ra is not greater than 0.3 μm, the photosensitive drum is sufficiently developed. This is because a large amount of toner cannot be supplied. However, when the surface roughness Ra exceeds 3 μm, the toner conveying force is too large,
Insufficiently charged toner is also conveyed, causing problems such as low image density.

As described above, in this embodiment, the surface of the aluminum developing sleeve is made to have an average inclination Δa of 0.0
01 or more and 0.1 or less, and the center line average roughness Ra is 0.3 to
3 μm, preferably diamond polishing,
Since it is formed by a series of blasting and Ni-P, Ni-B plating, or Cr plating, contamination of the developing sleeve surface due to toner fusion is greatly reduced without lowering the toner conveyance force. And a high quality image with sufficient density without white spots was obtained stably over a long period of time. Further, when the plating was performed, the abrasion resistance of the developing sleeve surface was improved, and the effect of preventing ghost images was also improved.

Embodiment 5 FIG. 15 is a sectional view showing still another embodiment of the developing device of the present invention. The outline of the developing device of this embodiment is shown in FIG.
Is the same as that of the fourth embodiment shown in FIG.
A method of reversal development using a C drum and a non-magnetic toner charged to a negative polarity as a developer is adopted. The image forming apparatus is a digital copier of 600 dpi at 16 sheets per minute.

The toner regulating system is a contact system, and the elastic blade 3 is integrally formed by bonding a urethane rubber plate (thickness 0.35 mm and a SUS plate (thickness 0.05 mm)) to a thickness of 0.45 mm. The toner was brought into contact with the developing sleeve 2 at a contact pressure of 15 g / cm, at which time the triboelectric charge of the toner was 21 μC / g. Has no magnet.

The developing sleeve 2 has a diameter of 20 mm. The surface of the developing sleeve 2 is mirror-finished by diamond polishing. Then, the surface of the developing sleeve 2 is blasted with spherical glass beads (FGB # 800) to give a surface roughness (center). Line average roughness) R
The surface was roughened to a = 0.38 μm to give a toner conveying ability.

In this embodiment, the surface of the developing sleeve 2 after diamond polishing and blasting was coated with a phenol resin layer containing crystalline graphite and conductive carbon. The coating of the resin layer has an effect of hardening the surface of the aluminum developing sleeve and suppressing generation of a ghost image. The use of a negatively charged toner is particularly effective because ghosts are more likely to occur than a positively charged toner.

In the present example, a resin solution was prepared by mixing a phenol resin with carbon and conductive graphite at a weight ratio of 100: 4: 36 to form a resin layer having a thickness of 20 μm. The aluminum sleeve blank was blasted and the resin layer was formed to a thickness of 5 μm as Comparative Example 3, the resin layer was formed to a thickness of 20 μm as Comparative Example 4, and the aluminum sleeve blank was diamond-polished. Table 9 shows the average inclination Δa, the developing sleeve contamination level, and the like of a case in which the resin layer was formed to a thickness of 20 μm as Example 2 of the present invention.

[0109]

[Table 9] The average inclination Δa of the developing sleeve having the 20 μm resin layer of the present embodiment is 0.08 as shown in Table 9.

As described above, in this embodiment, the surface of the aluminum developing sleeve is polished with diamond, blasted, and coated with a 20 μm-thick resin layer containing crystalline graphite and conductive carbon. And an average inclination Δa of 0.001 or more and 0.1 or less and a center line average roughness Ra of 0.3 μm or more and 3 μm or less. As a result, both the prevention of toner contamination of the developing sleeve and the toner conveying force can be improved, and even when 200,000 sheets of image are formed, the image density is 1.3.
The above was maintained.

As described above, according to the present embodiment, the non-magnetic toner charged to the negative polarity is used, and the developing device which regulates the non-magnetic toner by the elastic blade 3 is used in the digital copying machine. It was possible to maintain a high quality image with sufficient density up to 200,000 sheets, to improve the abrasion resistance of the developing sleeve, and to suppress the generation of a ghost image which is remarkable when a negatively charged toner is used.

Embodiment 6 In this embodiment, an OP having an outer diameter of 180 mm was used as a photosensitive drum.
The C photoreceptor was used, and the developing device performed reversal development using a two-component developer in which the nonmagnetic toner was negatively charged.

The two-component developer comprises a toner having an average particle size of 8 μm and a magnetic carrier having an average particle size of 50 μm. The developing device is the same as the developing device shown in FIG. 11, and, when described with reference to FIG. 11, the gap between the photosensitive drum 1 and the developing sleeve 2 is 500 μm, and the magnetic blade 8 having a thickness of 1.6 mm is connected to the developing sleeve 2. The layer thickness of the two-component developer on the developing sleeve 2 was regulated by providing a gap of 500 μm. The developing bias is such that the peak-to-peak voltage Vpp = 2 kV, the frequency f =
A rectangular wave of 3.0 kHz was used.

The surface of the developing sleeve 2 is polished with diamond, and spherical glass beads (FGB # 10
0), followed by amorphous alumina particles (A
(RD # 400) to roughen the surface to a surface roughness (center line average roughness) Ra = 0.3 to 3 μm, thereby imparting a developer conveying ability.

As in Example 5, the surface of the developing sleeve 2 is blasted and then coated with a phenol resin layer containing crystalline graphite and conductive carbon black to harden the aluminum surface, The average inclination Δa was adjusted to 0.001 to 0.1.

As an example, aluminum A6063
Diamond polishing the surface of the sleeve tube of FGB
(# 100), blasting pressure 3.0 kg / cm ^2, followed by ARD (# 400), after the two blasting blasting pressure 4.0 kg / cm ^2, on which conductive carbon phenolic resin, 1% by weight of crystalline graphite
A resin layer blended at 00: 3: 27 was formed to a thickness of 20 μm. As a result, the average inclination Δa =
A value of 0.06 and a surface roughness Ra of 0.45 were obtained.

As for the developing sleeve on which the resin layer is formed as in the present embodiment, the average inclination Δa is 0.001 or more.
One having a surface roughness Ra of not more than 1 and a surface roughness Ra of not less than 0.3 μm and not more than 3 μm was excellent in both the sleeve contamination level and the toner conveying force.

According to the present embodiment, since the surface of the developing sleeve is controlled as described above, it is possible not only to prevent the toner from adhering to and fusing to the surface of the developing sleeve, but also to develop the carrier even after long-term use. It does not come into contact with the undulations forming the fine irregularities and roughness on the sleeve surface many times, and therefore, it is possible to suppress the carrier deterioration more than before.

As described above, in the present embodiment, it is possible to reduce sleeve contamination and carrier deterioration by using a developing device using a two-component developer in which a non-magnetic toner is negatively charged in a digital copying machine. It is possible to stably obtain a high quality image with sufficient density without white spots for a long period of time. By the way, according to this embodiment, the density of 1.6 or more could be maintained for all four colors of yellow, magenta, cyan, and black even after forming 70,000 sheets of images.

Embodiment 7 The developing device of this embodiment is similar to Embodiment 1 shown in FIG.
A jumping development method using a magnetic toner of a magnetic one-component developer is employed. An image forming apparatus using this developing device has a process speed of 300 mm / sec and an image output of 60 sheets / min. Hereinafter, description will be made with reference to FIG.

The diameter of the developing sleeve 2 is 24.5 mm.
The elastic blade 3 (a total thickness of 0.4 mm obtained by bonding a silicone rubber plate having a thickness of 0.35 mm and a SUS plate having a thickness of 0.05 mm) is in contact with the developing sleeve 2 at a contact pressure of 12 g / cm.
Contacted.

This embodiment is characterized in that the surface of the developing sleeve 2 has an average inclination Δa of 0.001 or more and 0.1 or less, and the center line depth Rp and the center line height Rv satisfy Rp <Rv. It was formed in.

As described above, the toner contamination of the developing sleeve has no correlation with the surface roughness of the developing sleeve, that is, the center line average roughness Ra and the ten-point average roughness Rz.
There is a correlation with a. However, even on the surface of the developing sleeve having the same value of the average inclination Δa, as shown in FIG. 16 and Table 10, depending on the surface shape, that is, the magnitude relation between the center line depth Rp and the center line height Rv, It has been found that when the relationship of Rp <Rv is satisfied, there is a difference in the contamination of the developing sleeve, and the contamination level is greatly improved. The center line depth Rp and the center line height Rv are defined as shown in FIG.

[0124]

[Table 10] FIG. 18 shows the surface shape of the developing sleeve when Rp> Rv.
FIG. 18A shows the surface shape of the developing sleeve when Rp <Rv. Average inclination Δa of developing sleeve
Is the same in FIGS. 18A and 18B. FIG.
(A) and (b) show one toner particle by a dotted line.

Even if the average inclination Δa of the developing sleeve is the same, as shown in FIGS. 18A and 18B, Rp <
In the case of Rv (FIG. 18 (b)), the toner easily passes over the unevenness on the surface, and the contamination by adhesion and fusion of the toner on the surface of the developing sleeve is small. This is because the toner contamination on the surface of the developing sleeve is
It is considered that the toner contamination is reduced in the case of Rp <Rv where the resistance to the catch at the peak portion is small, since it is considered to occur when the peak cannot be crossed.

As described above, in this embodiment, by setting the average slope Δa of the developing sleeve surface to 0.1 or less, toner contamination of the developing sleeve is reduced, and the center line depth Rp is further reduced.
By setting the relationship between Rv and the center line height Rv as Rp <Rv, the toner contamination of the developing sleeve is further reduced.

Specifically, the surface of the sleeve tube made of aluminum A6063 is polished with diamond, and the pressure is 3.0 kg / cm ² with spherical glass beads (FGB # 300).
And a phenolic resin layer containing crystalline graphite and conductive carbon is coated thereon with a film thickness of 2
The average inclination Δa is 0.0
Center line depth Rp <center line height R from 01 to 0.1
An aluminum developing sleeve having a surface of v was obtained.

In this embodiment, as in the case of the fourth embodiment and the like, the pre-treatment for the blasting is polished with diamond. Similarly, the jaggedness at the time of cutting as shown in FIG. As shown in FIG. 14 (b), the surface state is almost completely eliminated by diamond polishing to improve the surface state. As a result, even if the toner is restricted by strongly pressing the magnetic toner against the developing sleeve 2 by the elastic blade 3 as in the present embodiment, the toner can be hardly adhered to the surface, and the control of the average inclination Δa can be achieved. The toner contamination on the surface of the developing sleeve can be satisfactorily prevented.

As described above, in this embodiment, the surface of the aluminum sleeve tube was polished with diamond, blasted, and coated with a resin layer containing crystalline graphite and conductive carbon to a thickness of 20 μm. Since the surface of the developing sleeve is formed so that the inclination Δa is 0.001 or more and 0.1 or less and the center line depth Rp <the center line height Rv, it is excellent in preventing toner contamination on the surface,
The image density of 1.3 or more could be maintained even after the image formation of 10,000 sheets.

According to the present embodiment, the developing device in which the magnetic toner is regulated by the elastic blade is used in a copying machine, so that toner contamination of the developing sleeve can be reduced, there is no white spot, and the density is sufficiently high. An image of high quality could be obtained stably over a long period of time. By the way, according to this embodiment,
Sufficient density can be maintained up to 300,000 sheets of image formation.

Example 8 In this example, a sleeve tube made of aluminum A6063 was used, and the surface thereof was polished with diamond, blasted, and provided with irregularities to impart toner transfer force. From Ni-P plating or Ni
By performing -B plating or Cr plating, the average inclination Δa was controlled to 0.001 to 0.1, and the centerline depth Rp was controlled to be less than the centerline height Rv.

The other points of the developing device of this embodiment are shown in FIG.
5, the elastic blade 3 was in contact with the developing sleeve 2 at 12 g / cm.

As described above, if the above plating is applied,
The average inclination Δa of the developing sleeve surface can be easily adjusted to the desired value of 0.0.
In addition to being easily controllable to a value of from 0.1 to 0.1, the surface of aluminum having poor abrasion resistance can be easily hardened to improve the abrasion resistance of the developing sleeve. When a neutrally charged magnetic toner is used, the above-mentioned plating surface can provide an appropriate positive charge to the magnetic toner, which is effective in preventing ghosting.

In this embodiment, aluminum A606
The surface of the sleeve tube of No. 3 was polished with diamond and pressed with spherical glass beads (FGB # 800) at a pressure of 4.0 kg /
blasting with cm 2, and Ni-
By applying P plating to a thickness of 20 μm, the surface of the developing sleeve can be formed so that the average inclination Δa is 0.001 or more and 0.1 or less, and the center line depth Rp <center line height Rv. A developing sleeve excellent in preventing contamination was obtained. Also in this case, Ni-B plating or Cr plating may be used instead of Ni-P plating.

As described above, according to this embodiment, the surface of the aluminum developing sleeve is plated with Ni-P, so that the surface of the developing sleeve has an average inclination Δa of 0.001 to 0.1. And the center line depth Rp <center line height Rv, and the contamination of the surface of the developing sleeve due to the fusion of the toner can be greatly improved, and there is no white spot. A high-quality image with a sufficient density could be stably obtained over a long period of time. The plating coating also improved the abrasion resistance of the developing sleeve surface and the effect of preventing ghost images.

Example 9 In this example, a non-magnetic cyan cyan toner having an average particle diameter of 6 μm and being negatively charged was used as a one-component developer. The other points of the developing device of this embodiment are the same as those of Embodiment 7 shown in FIG. 15, and the elastic blade 3 is made of a urethane rubber plate (thickness 0.35 mm) and a SUS plate (thickness 0.05 mm). They were laminated and integrally formed, and the contact pressure against the developing sleeve 2 was 15 g / cm.

In this example, the aluminum sleeve blank was blasted at 2.0 kg / cm ² with FGB # 800 without diamond polishing, and phenol resin, crystalline graphite and carbon were weighed on top of it. A resin layer mixed at a ratio of 100: 2: 18 with a thickness of 25 μm
m, and as a finishing treatment # 300
Polishing was performed using a wrapping tape of No. 0 at a pressure of 500 g / cm. Thus, the center line depth Rp = 1.1 μm and the center line height Rv = 2.3 μm are formed on the surface of the developing sleeve 2.
Thus, a surface state having an average inclination Δa = 0.07 was obtained.

Some experiments have shown that it is effective to set the center line depth Rp to preferably not more than half of the center line height Rv. However, the above values Rp and Rv are:
It is controlled that way.

The present embodiment is configured as described above, and the surface of the developing sleeve has an average inclination Δa of 0.001 to 0.1.
And the centerline depth Rp <centerline height Rv, so that contamination of the surface of the developing sleeve due to fusion of the toner can be greatly improved, and the developing device can be used in a color image forming apparatus. A high-quality color image with sufficient density and no white spots was obtained stably up to 200,000 sheets with a long service life.

[0140]

As described above, according to the present invention,
The surface of the developing sleeve of the developing device has an average inclination Δa of 0.
001 and 0.1 or less, and the toner regulating pole N1 of the magnet in the developing sleeve is disposed so as to have a magnetic force peak near the free end of the elastic blade. Since it is 20 ° or more and 50 ° or less, it is possible to greatly reduce the contamination due to the fusion of the toner on the surface of the developing sleeve without causing a decrease in the toner conveying force, and to obtain a high quality image having a sufficient density without white spots. Image could be obtained stably over a long period of time. When the surface of the developing sleeve is coated with a resin layer containing crystalline graphite and conductive carbon, or when Ni-P plating, Ni-B plating, or Cr plating is applied, the surface of the developing sleeve is Not only can the abrasion resistance be improved and the ghost image can be effectively prevented, but also there is an effect that the control of the average inclination Δa becomes easy.

According to another aspect of the present invention, the surface of the aluminum developing sleeve is provided with an average inclination Δa of 0.001 or more and 0.1 or less and a center line average roughness Ra of 0.3 to 3 μm.
Similarly, contamination of the developing sleeve surface due to fusion of the toner can be significantly improved without a decrease in the toner conveying force, and there is no white spot and the density is sufficiently high. An image of high quality could be obtained stably over a long period of time. At this time, the surface of the developing sleeve was polished with diamond, blasted, and Ni-P
When a series of plating, or Ni-B plating, or Cr plating, or coating of a resin layer containing crystalline graphite and conductive carbon is performed, the abrasion resistance of the developing sleeve surface is improved and a ghost image is formed. Not only can be effectively prevented, but also the average slope Δa
Control becomes easy.

According to still another aspect of the present invention, the surface of the aluminum developing sleeve is provided with an average inclination Δa of 0.0
Since it is formed so that the center line depth Rp is less than or equal to 0.1 and the center line depth Rp is less than the center line height Rv, similarly, the toner conveying force due to the toner fusing on the developing sleeve surface does not decrease. Contamination can be greatly reduced, and a high-quality image with sufficient density without white spots can be stably obtained over a long period of time. Similarly, the surface of the developing sleeve is polished with diamond, blasted, and Ni-P
Plating, Ni-B plating, or Cr plating, or coating a resin layer containing crystalline graphite and conductive carbon, effectively improves the wear resistance of the developing sleeve surface and prevents ghost images. And the average inclination Δa can be easily controlled.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a developing device of the present invention.

FIG. 2 is a diagram illustrating a state of a surface when a developing sleeve of the developing device of FIG.

FIG. 3 is an explanatory diagram for defining an average inclination Δa of a developing sleeve surface defined in the embodiment of FIG. 1;

FIG. 4 is an explanatory diagram schematically showing the surface shapes of developing sleeves having different average inclinations Δa in FIG. 3;

5 is a graph showing the relationship between the average inclination Δa of the developing sleeve and the density difference ΔD at the beginning of image formation and after long-term use in the embodiment of FIG.

FIG. 6 is a cross-sectional view illustrating a conventional toner-regulating developing device using an elastic blade.

FIG. 7 is an explanatory diagram showing various examples of an arrangement position of a toner regulating pole N1 of a magnet in a developing sleeve with respect to an elastic blade in the embodiment of FIG. 1;

8 is an explanatory diagram showing a state of toner flow near an elastic blade in some arrangement examples of the regulating pole N1 in FIG. 7;

FIG. 9 is a diagram illustrating a range of the average inclination Δa of the developing sleeve in which both the toner coating amount and the developing sleeve contamination level are preferable.

FIG. 10 is a diagram showing the average inclination Δa of the developing sleeve and the range of the arrangement position of the regulating pole N1 satisfying all of the toner coating amount, the developing sleeve contamination, and the application of the triboelectric charge.

FIG. 11 is a sectional view showing another embodiment of the developing device of the present invention.

12 is a graph showing the average inclination Δa of the developing sleeve and the density difference ΔD between the initial stage of image formation and after long-term use in the embodiment of FIG.
6 is a graph showing a relationship with the graph.

FIG. 13 is an explanatory view schematically showing the shapes of a blasted surface of a developing sleeve, a surface subjected to Ni-P plating after blasting, and a surface subjected to Ni-P plating after diamond polishing and blasting. It is.

FIG. 14 is an explanatory view schematically showing the shape of the surface of the developing sleeve as-cut before blasting and the surface polished with diamond after cutting.

FIG. 15 is a sectional view showing another embodiment of the developing device of the present invention.

FIG. 16 shows the relationship between the average inclination Δa of the developing sleeve and the density difference ΔD at the initial stage of image formation and after long-term use in a developing device according to another embodiment of the present invention. It is a graph which shows that it changes with the magnitude relationship between Rv.

FIG. 17 is an explanatory diagram defining a center line depth Rp and a center line height Rv defined in the embodiment of FIG. 17;

FIG. 18 is a view schematically showing that the surface shape of the developing sleeve differs depending on the magnitude relationship between the center line depth Rp and the center line height Rv.

FIG. 19 is a view showing a solid image having unevenness due to periodic white spots that has occurred due to toner contamination of a developing sleeve in a conventional developing device.

FIG. 20 is a graph showing the relationship between the surface roughness Ra of the developing sleeve and the density difference ΔD at the beginning of image formation and after long-term use.

FIG. 21 is a graph showing the relationship between the surface roughness Rz of the developing sleeve and the density difference ΔD at the beginning of image formation and after long-term use.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum 2 developing sleeve 3 elastic blade 6 magnet 8 magnetic blade N1 toner regulating pole

Claims (23)

[Claims] 1. An elastic regulating member which carries a developer on a rotating developer carrier having a magnet on the inside, and which has a layer thickness of the developer carried on the developer carrier in contact with the developer carrier. The developer transported to the developing unit facing the image carrier by the rotation of the developer carrier is used for developing an electrostatic latent image formed on the image carrier. The surface of the agent carrier has an average inclination Δa of 0.001 or more and 0.1
And a magnet having a magnetic pole having a magnetic force peak near the free end of the elastic regulating member. 2. The developing device according to claim 1, wherein a half width of said magnetic pole is not less than 20 ° and not more than 50 °. 3. The surface of the developer carrying member is subjected to a surface roughening treatment so that the average inclination Δa is 0.001 or more.
3. The developing device according to claim 1, wherein the developing device is adjusted to 1 or less. 4. The surface of the developer carrying member is subjected to a surface roughening treatment, and a resin layer containing crystalline graphite and conductive carbon is coated thereon, so that the average inclination Δa is 0.001 or more. 3. The developing device according to claim 1, wherein the developing device is adjusted to 1 or less. 5. The surface of the developer carrying member is subjected to a roughening treatment, and a Ni—P plating layer, a Ni—B plating layer, or a Cr plating layer is coated thereon, so that the average inclination Δa is reduced. 3. The developing device according to claim 1, wherein the developing device is adjusted to 0.001 or more and 0.1 or less. 6. The developing device according to claim 1, wherein the material of the developer carrier is stainless steel or aluminum. 7. The developing device according to claim 1, wherein the developer is a magnetic one-component developer charged to a positive polarity. 8. A developer-carrying member, wherein the developer is carried on the developer-carrying member, and the layer thickness of the developer carried on the developer-carrying member is regulated by a regulating member. In the developing device, the developer conveyed to the developing section is used for developing an electrostatic latent image formed on the image carrier, the surface of the developer carrier has an average inclination Δa of 0.001 or more. A developing device having a center line average roughness Ra of not more than 1 and not more than 0.3 μm and not more than 3 μm. 9. The surface of the developer carrying member is polished with diamond, blasted, and a resin layer containing crystalline graphite and conductive carbon is coated thereon, so that the average inclination Δa is 0.001 or more. 0.1
9. The developing device according to claim 8, wherein the center line average roughness Ra is adjusted to 0.3 μm or more and 3 μm or less. 10. The surface of the developer carrier is polished with diamond, blasted, and a Ni—P plating layer, a Ni—B plating layer, or a Cr plating layer is coated thereon, so that the average inclination is increased. 9. The developing device according to claim 8, wherein Δa is adjusted to 0.001 or more and 0.1 or less, and the center line average roughness Ra is adjusted to 0.3 μm or more and 3 μm or less. 11. The developing device according to claim 8, wherein a material of said developer carrier is aluminum. 12. The developing device according to claim 8, wherein said developer is a magnetic one-component developer. 13. The developing device according to claim 8, wherein the developer is a non-magnetic one-component developer. 14. The developing device according to claim 8, wherein said developer is a two-component developer. 15. The developing device according to claim 12, wherein said regulating member is an elastic regulating member. 16. The developing device according to claim 12, wherein said regulating member is a magnetic regulating member. 17. The developing device according to claim 8, wherein a material of said developer carrying member is aluminum. 18. An elastic regulating member which carries a developer on a rotating developer carrier having a magnet on the inside, and which has a layer thickness of the developer carried on the developer carrier in contact with the developer carrier. The developer transported to the developing unit facing the image carrier by the rotation of the developer carrier is used for developing an electrostatic latent image formed on the image carrier. The surface of the agent carrier has an average slope Δa of 0.001 or more.
1 or less, the center line depth Rp and the center line height Rv of the surface roughness
Wherein Rp <Rv. 19. The surface of the developer bearing member is polished with diamond, blasted, and coated with a resin layer containing crystalline graphite and conductive carbon, so that the average inclination Δa is 0.001 or more. 0.
1 or less, the center line depth Rp and the center line height Rv of the surface roughness
19. The developing device according to claim 18, wherein Rp <Rv. 20. The surface of the developer carrying member is polished with diamond, blasted, and a Ni—P plating layer, a Ni—B plating layer, or a Cr plating layer is coated thereon, thereby obtaining the average inclination. Δa is 0.001 or more and 0.1 or less, and the center line depth R of the surface roughness is
19. The developing device according to claim 18, wherein the relationship between p and the center line height Rv is adjusted so that Rp <Rv. 21. A surface of the developer carrying member is blasted, a resin layer containing crystalline graphite and conductive carbon is coated thereon, and the surface is polished with a lapping tape. 0.001 or more and 0.1 or less, and the center line depth R of the surface roughness
19. The developing device according to claim 18, wherein the relationship between p and the center line height Rv is adjusted so that Rp <Rv. 22. The developing device according to claim 18, wherein said developer is a magnetic one-component developer. 23. The developing device according to claim 18, wherein said developer is a non-magnetic one-component developer.