JP2002006619A - Developing device and method for manufacturing developer carrier used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device with which an image with excellent image quality is stably obtained for a long period of time by suppressing developer sleeve contamination by melt-sticking of a toner and by stabilizing the quantity of carried developers of a developer sleeve to a developing area. SOLUTION: In the developing device having the developer sleeve, blast processing for the surface of the developer sleeve is performed with spherical particles with a fixed form which have the mean diameter d satisfying a relation of D<=d<=10 D for the average particle diameter D of a magnetic carrier in a two-component developer, and he ten-point average roughness Rz of the surface of the developer sleeve is set so as to satisfy a relation of D/6<=Rz<=D/2 for the average particle diameter D of the magnetic carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for visualizing an electrostatic latent image formed on an image bearing member (hereinafter, referred to as a "photosensitive drum") by attaching a developer to the electrostatic latent image. A developing device used in an image forming apparatus such as a copying machine and a laser beam printer using an electrophotographic method or an electrostatic recording method, and a developer carrying member (sleeve shape is representative) used to transport the developer. In particular, the present invention relates to a method for manufacturing a developer sleeve for making the conveying surface of the developer sleeve an appropriate surface shape.

[0002]

2. Description of the Related Art In a developing apparatus used in an image forming apparatus such as a copying machine using an electrophotographic method, a developer is attached to a latent image formed on a photosensitive drum to visualize the image by attaching a developer. As the developer sleeve, for example, a metal developer sleeve is used, the developer contained in the developing container is carried on the sleeve, and is transported to a development area facing the photosensitive drum, and is placed on the photosensitive drum. The formed electrostatic latent image is developed with a developer to visualize the latent image.

[0003] 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 developer sleeve is selected depending on the developer. In the case of the two-component developer which is the object of the present invention, a developer sleeve provided with a magnetic field generating means such as a magnet inside is used, and the material thereof is a non-magnetic metal such as stainless steel or aluminum material. Is conventionally mainly used.

In the above-described developing device, the surface of the developer sleeve is roughened, so that the transportability of the two-component developer composed of the toner and the carrier to the developing area is improved. As a result, a uniform developer layer can be coated on the surface of the developer sleeve. As a method for roughening the surface of the developer sleeve, in the case of the two-component developing method, an irregular blast method (sand blast method) using irregular particles has been mainly performed.

In the irregular blasting method, fine irregularities are formed on the metal surface by spraying irregular-shaped sand having sharp edges, alumina particles, silicon oxide, or the like at a high speed. When the surface of the developer sleeve subjected to the irregular blast processing is enlarged, it is in a rough state where countless fine grooves are present. As described above, the surface of the developer sleeve is roughened by the irregular blasting, thereby improving the transportability of the developer.

[0006]

However, on the other hand, the following problems exist in the developer sleeve whose surface is subjected to irregular blast processing. In the case of a developer sleeve whose surface is roughened by an irregular blasting method, the surface of the developer sleeve is rough with many fine grooves. It becomes caught in the valleys of the fine irregularities on the surface that has been converted, and is easily attached thereto. The toner adhering to the valley is fused to the surface over a long period of use by pressing the layer thickness regulating member or the like that regulates the layer thickness of the developer on the surface of the developer sleeve. There is a possibility that the toner is contaminated (hereinafter, a state in which the toner is fused to the surface of the developer sleeve is referred to as “developer sleeve contamination”).

Further, when a two-component developer containing a carrier is used, if the surface of the developer sleeve has irregularities, the toner or a component in the toner is reduced by the pressing of the carrier to the valleys of the fine grooves on the roughened surface. It becomes easy to be embedded in. The toner embedded in the valley is fused to the toner after a long use, and the surface of the developer sleeve tends to be contaminated with the toner. In particular, in response to the demand for high image quality and reduction in power consumption of copiers in response to increasing demand for color copiers and the like in recent years, as toner particle size and softening point are reduced, long-term use The toner or a component in the toner is fused to the uneven portion on the surface of the developer sleeve, and the tendency to cause contamination of the developer sleeve is increased.

When the toner is fused on the surface of the developer sleeve, first, the amount of the developer transported to the developing area decreases, and the density of the formed image decreases. Conventionally, an alternating electric field (development bias) is often applied to the developer sleeve at the time of development in order to perform good development. However, when toner fusion occurs on the surface of the developer sleeve, the developer sleeve is The fused material on the surface becomes a high-resistance layer, and a desired electric field is not formed in a developing region between the developer sleeve and the photosensitive drum during development. As a result, a sufficient developing effect cannot be obtained by the developing bias, and the density of an image to be formed is reduced, and image defects such as white spots occur.

In particular, in the two-component developing system, the development efficiency (the ratio of toner that can be consumed for development among the toner present in the developing section) is improved and the size of the apparatus is reduced. A method of forming a thin layer of a developer and applying an alternating electric field to a developing portion to perform development is often used. In this method, since the magnetic carrier ears on the developer sleeve are sparse, toner attached to the surface of the developer sleeve can be supplied to the photosensitive drum without being hindered by the magnetic carrier ears. Thus, high development efficiency is achieved by causing the toner attached to the surface of the developer sleeve to fly from the surface of the developer sleeve to the surface of the photosensitive drum by an alternating electric field. However, when this method is used, toner fusing occurs on the surface of the developer sleeve, and a high-resistance layer is formed by the fusing material. Efficiency is reduced and image defects occur.

[0010] Actually, a non-contaminated developer sleeve and a contaminated developer sleeve were prepared, and an image was evaluated using the same developer. In the sleeve, the image density was reduced by 0.2 or more at the maximum, and image defects such as white spots occurred. From this, it is apparent that the contamination of the surface of the developer sleeve by the fusion of the toner causes a decrease in the density of a formed image, a decrease in development efficiency, and an image defect.

As described above, in the case of the developer sleeve subjected to the irregular blasting using the irregular particles, the surface is contaminated by the fusion of the toner, so that some problems arise. However, the purpose of applying the irregular blast to the surface of the developer sleeve was to improve the transportability when transporting the two-component developer to the development area. Therefore, if blasting is not performed, a problem will arise in the transportability of the developer.

An object of the present invention is to solve the above-mentioned problems of the prior art and to prevent toner from being buried in valleys on the surface of a developer sleeve by a carrier when a two-component developer is used. Developing device capable of suppressing developer sleeve contamination due to toner fusion and stabilizing the amount of developer transport of the developer sleeve to a developing area, thereby stably obtaining a high-quality image for a long period of time. It is to provide. The present inventors have conducted various studies to achieve the above object, and as a result, the surface of the developer sleeve is roughened with a brass material satisfying a specific condition, and the surface is set to a specific surface roughness. The present inventors have found that contamination of the developer sleeve is prevented, and that the transportability of the developer is also stabilized and improved, thereby completing the present invention.

[0013]

The above object is achieved by the present invention described below. That is, the present invention is used in an image forming apparatus having means for forming an electrostatic latent image corresponding to an image information signal on a photosensitive drum, and the electrostatic latent image on the photosensitive drum has a non-magnetic toner and a magnetic carrier. In a developing device having a developer sleeve that carries the two-component developer and conveys the toner to a development area when a toner image is formed by developing using a two-component developer, a surface of the developer sleeve includes: The average particle diameter D of the magnetic carrier in the two-component developer is blasted with regular spherical particles having an average diameter d that satisfies the following relationship: D ≦ d ≦ 10D, and ten points on the surface of the developer sleeve Average roughness Rz
Is set so as to satisfy the following relationship with respect to the average particle diameter D of the magnetic carrier: D / 6 ≦ Rz ≦ D / 2.

Further, the present invention is used in an image forming apparatus having means for forming an electrostatic latent image corresponding to an image information signal on a photosensitive drum. A method for manufacturing a developer sleeve for carrying a two-component developer and transporting it to a development area, provided in a developing device that forms a toner image by developing using a two-component developer having a carrier, A step of blasting the surface of the developer sleeve with regular spherical particles having an average diameter d that satisfies the following relationship with respect to the average particle diameter D of the magnetic carrier in the two-component developer. The ten-point average roughness Rz of the surface of the developer sleeve is, with respect to the average particle diameter D of the magnetic carrier,
A method for producing a developer sleeve is provided, wherein the method is adjusted so as to satisfy the following relationship: D / 6 ≦ Rz ≦ D / 2. In the present invention, the average particle diameters of the magnetic carrier, the toner and the blast particles are all weight average particle diameters.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in more detail with reference to embodiments and examples. Preferred embodiments of the developing device in the present invention are as follows. (1) The developing device having an electric field forming means for forming an alternating electric field between the photosensitive drum and the developer sleeve. (2) After the surface of the developer sleeve is subjected to diamond polishing, the surface is cleaned. (3) The developing device, wherein the blast processing is performed with the regular spherical particles, (3) the developing device, wherein the surface of the developer sleeve is subjected to the blast processing with the regular spherical particles, and then the surface is further subjected to electroless plating; The developing device in which the material of the developer sleeve is aluminum or stainless steel; (5) the electroless plating is electroless Ni-P plating, electroless Ni-B plating, or electroless P;
(6) the non-magnetic toner has an average particle diameter of 2 to 10;
μm.

A preferred embodiment of the method for manufacturing a developer sleeve according to the present invention is as follows. (1) a method for producing the developer sleeve in which the regular spherical particles are glass beads, stainless steel spheres, or ceramic spheres; and (2) a surface of the developer sleeve,
A method of manufacturing the developer sleeve, comprising a step of polishing the surface of the developer sleeve with diamond before the step of blasting with the regular spherical particles; (3) blasting the surface of the developer sleeve with regular spherical particles (4) a method for manufacturing the developer sleeve, comprising a step of performing electroless plating on a surface of the developer sleeve after the processing step;
A method for manufacturing the developer sleeve, wherein the material of the developer sleeve is aluminum or stainless steel,
(5) the method of manufacturing the developer sleeve, wherein the electroless plating is electroless Ni-P plating, electroless Ni-B plating, electroless Pd-P plating, or electroless Cr plating; Non-magnetic toner having an average particle size of 2 to 10 μm
The method for manufacturing the developer sleeve, wherein

According to the above configuration, when the two-component developer is used, the carrier prevents the toner from being embedded in the valleys of the irregularities on the surface of the developer sleeve, and eliminates the contamination of the developer sleeve due to the fusion of the toner. The amount of developer transported by the developer sleeve to the developing area is also stabilized, and the quality of an image formed by the developer can be stably guaranteed for a long time, thereby achieving the object of the present invention.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a developing device according to the present invention. The developing device of the present invention is used, for example, in an image forming apparatus described below, but is not necessarily limited to this embodiment. <Embodiment 1 and Comparative Examples 1-4> FIG. 1 shows one of the stations Y, M, C and Bk in the full-color image forming apparatus as shown in FIG.
The Y, M, C, and Bk stations have substantially the same configuration, and form yellow (Y), magenta (M), cyan (C), and black (Bk) images, respectively, in a full-color image. In the following description, for example, if there is the developing device 1, the developing device 1Y, the developing device 1M, the developing device 1C, and the developing device 1Bk in each of the Y, M, C, and Bk stations are commonly referred to.

First, the operation of the entire image forming apparatus of the present invention will be described with reference to FIG. The photosensitive drum 4 is rotatably provided. The photosensitive drum 4 is uniformly charged by a primary charger 21 and, for example, light modulated according to an image information signal by a light emitting element 22 such as a laser. To form an electrostatic latent image on the photosensitive drum 4. The electrostatic latent image is visualized by the developing device 1 as a toner image in a process described below. Next, the visible image is transferred to the transfer paper 27 conveyed by the transfer paper conveyance sheet 24 by the transfer charger 23, and further fixed by the fixing device 25 to obtain a permanent image. The transfer residual toner on the photosensitive drum 4 is removed by the cleaning device 26. Further, the toner consumed in the image formation is supplied from the toner supply tank 6.

Next, the operation of the developing device will be described with reference to FIG. In FIG. 1, a developing device 1 arranged to face a photosensitive drum 4 has a developer container 2, a developer sleeve 3 as a developer carrying means, and a blade 5 as a developer height control member. . The developer container 2 is divided into two by a partition.
And a two-component developer containing a non-magnetic toner and a magnetic carrier.

The developer container 2 of the developing device 1 has an opening in a developing region facing the photosensitive drum 4, and a developer sleeve 3 is rotatably disposed so as to be partially exposed at the opening. . The developer sleeve 3 is made of a non-magnetic material and rotates in the direction of the arrow in FIG. 1 during a developing operation, and a magnet 7 serving as a magnetic field generating means is fixed inside the sleeve. The developer sleeve 3 containing the magnet 7 carries and transports the layer of the two-component developer whose thickness is regulated by the blade 5 from the developer reservoir to the developing area. To the photosensitive drum 4 to develop the electrostatic latent image formed on the photosensitive drum 4.

Here, the magnet 7 will be further described. The magnet 7 is composed of five poles, and the developer stirred by the stirring screw 8 is moved by the magnetic force of the transport magnetic pole (pumping pole) N2 for pumping. The developer is constrained on the sleeve 3, and then a layer of developer is formed by the action of the regulating magnetic pole (S <b> 2) and the regulating blade 5, and is conveyed while forming a magnetic brush. Next, the developer is conveyed to the developing area by the magnetic force of the conveying magnetic pole N1 and the rotation of the developer sleeve 3. The developer after developing the electrostatic latent image on the photosensitive drum 4 in the developing area is transported from the developing area to the developing container 2 by the magnetic force of the take-in pole N3 and the rotation of the developer sleeve 3.

Here, the take-in pole N3 and the pumping pole N2
Have the same polarity, and a region (repulsion pole) where the magnetic force is approximately 0 Gauss is provided between the two magnetic poles. As a result, the developer after developing the electrostatic latent image is stored in the developing container 2 without being continuously drawn up and restrained by the pole N2. In the case of the configuration in which the repelling pole is provided as in the present embodiment, the rotation of the developer is reduced by the repelling pole, so that the toner adheres to the surface of the developer sleeve 3 and becomes less likely to stay. This has the effect of reducing toner fusion to the toner. Therefore, when the magnet 7 having the repulsive pole and the developer sleeve 3 having the surface configuration described below are used in combination as in this embodiment, it is effective to reduce the contamination of the developer sleeve.

Next, the characteristic portions of this embodiment will be described in more detail. As described in the section of the prior art, in a developer sleeve having a roughened surface by irregular blasting, toner or components in the toner adhere to fine irregularities on the surface of the roughened developer sleeve. Alternatively, the surface of the developer sleeve may be contaminated due to easy fusion. Therefore, in this embodiment, it is necessary to perform blast processing different from irregular blast processing.

Therefore, glass beads were prepared as regular blast particles, and blasting was performed. The method of blast processing is as follows. A blast nozzle having a diameter of 7 mm, which is 100 mm away from the developer sleeve, is moved in parallel to the axis of the developer sleeve with respect to the developer sleeve rotating at 12 rpm. Blast pressure)
Glass beads were sprayed on the surface of the developer sleeve at 3 kg / cm ² . In this way, the surface of the developer sleeve was blasted, and the surface was roughened.

After the blast treatment, the surface of the developer sleeve was washed and dried. The conditions such as the rotation speed, the distance of the blast nozzle from the developer sleeve, and the blast pressure were slightly changed depending on the material of the developer sleeve tube. The blast conditions are not limited to these. Further, in the present embodiment, glass beads were used as the regular blast particles.However, the regular blast particles are not limited to these.For example, using stainless steel balls, ceramic balls, steel balls, ferrite balls, and the like. Is also good. However,
Since steel balls and ferrite balls are magnetic materials, they are not very suitable for blasting by incorporating a permanent magnet member in a developer sleeve.

First, as Experiment Example 1 (Comparative Example 1), # 40
SUS developer sleeve whose surface has been roughened by blasting using amorphous alumina particles (ARD # 400) of 0 mesh (according to JIS standard), and # 400 mesh standard as Experimental Example 2 (Comparative Example 2) A SUS developer sleeve whose surface was roughened by blasting using glass bead particles (FGB # 400) was prepared.

Using each of these developer sleeves,
The degree of contamination of the developer sleeve after the long-term use of 40,000 sheets was evaluated. At this time, the magnetic carrier has an average particle size of 40.
μm, and the toner used had an average particle diameter of 7 μm. The contamination density was evaluated using a reflection type densitometer, and the reflected light from the surface of the developer sleeve before and after use was measured, and the optical density difference ΔD was taken as the contamination density. The results are shown in Table 1 below. In the developer sleeve subjected to the irregular blast treatment of Comparative Example 1 after the long-term use of 40,000 sheets, the toner was fused to the surface of the developer sleeve. on the other hand,
The amount of the toner fused to the surface of the developer sleeve of the developer sleeve of the comparative example 2 which was subjected to the regular blast treatment with the regular glass bead particles was smaller than that of the developer sleeve of the comparative example 1 which had undergone the irregular blast treatment. Also, the effect on image quality due to developer sleeve contamination was small.

Compared with the irregularly blasted developer sleeve of Experimental Example 1 (Comparative Example 1), the fixed blasted developer sleeve of Experimental Example 2 (Comparative Example 2) has toner and the like on the surface of the developer sleeve. The surface of the developer sleeve of Experimental Example 2 (Comparative Example 2) is enlarged to investigate the reason why it is difficult to adhere, and it is different from the rough state in which infinite number of fine grooves were present in the case of irregular blasting. The grooves were substantially spherical, reflecting the regular glass beads used for blasting, and were composed of relatively smooth grooves with few fine grooves. As described in the section of the prior art for a while, according to the idea of the present inventors, when the amorphous blast processing is performed,
When toner is buried in the fine and jagged grooves with a rough surface by pressing a magnetic carrier or the like, the toner becomes difficult to move, and heat is stored by compression of a layer thickness regulating member or the like,
It is believed that it will fuse during prolonged use. Therefore,
The surface of the developer sleeve blasted with spherical glass beads is compared to the surface blasted with irregular shaped blast.
It is considered that there were few fine irregularities, and the developer sleeve surface was less likely to be contaminated with toner.

As in Experimental Example 2 (Comparative Example 2), if the surface of the developer sleeve is subjected to a regular blasting treatment with spherical glass beads or the like, the surface of the developer sleeve becomes smooth and the level of contamination of the developer sleeve can be reduced. . However, when the surface of the developer sleeve becomes smooth, the transportability of the developer decreases,
There is a concern that it may be difficult to supply sufficient developer to the photosensitive drum. Actually, spherical glass beads of # 400 mesh (FGB # 4) as in Experimental Example 2 (Comparative Example 2)
In the case of the SUS developer sleeve subjected to the standard blasting process according to (00), the transportability when the two-component developer is transported to the development area is reduced, and as a result, the formed image quality starts to be affected.

Therefore, for some SUS developer sleeves and aluminum developer sleeves, their surfaces were roughened by blasting using spherical glass bead particles (FGB), and the surface roughness was measured. A comparison was made between the surface roughness and the degree of contamination of the developer sleeve after long-term use of 40,000 sheets and the transportability. Table 1 shows the results.

For measuring the surface roughness, a contact type surface roughness meter (manufactured by Kosaka Laboratory Co., Ltd .: Surfcoder SE-3300)
Was used to measure the ten-point average roughness Rz of the surface of the developer sleeve. The measurement conditions are a cutoff value of 0.8 mm, a measurement length of 2.5 mm, a feed speed of 0.1 mm / sec, and a magnification of 5000 times. Here, Rz is JIS B
0601 is a ten-point average roughness, which qualitatively represents a height difference between uneven peaks and valleys.

[0033]

[Table 1]

The evaluation criteria in the above Table 1 are as follows. Contamination level ×: toner fusion is severe and affects the image (white spots, etc.) ○: toner fusion occurs slightly, but does not affect image quality ◎: toner fusion hardly occurs Transportability ×: transport The transport amount of the developer on the developer sleeve is conspicuous due to the deterioration of the performance. Δ: The transport amount is uneven depending on the environment and conditions. ○: The transport amount of the developer on the developer sleeve is stable. There is a problem in both the level and the transportability. △: A problem may occur in either the contamination level or the transportability. ○: There is no problem in both the contamination level and the transportability.

The SUS developer sleeve of the above-described Experimental Example 2 (Comparative Example 2), the surface of which has been subjected to a regular blast treatment with # 400 mesh spherical glass beads (FGB # 400),
As mentioned earlier, contamination of the developer sleeve has been reduced,
The transportability of the developer also deteriorated, and there was a practical problem. On the other hand, from the results in Table 1, it can be seen from the results of (1) that the ten-point average roughness Rz of the surface of the developer sleeve becomes large, and that (2) the particles for blasting the developer sleeve become coarse (the number of mesh is made small). Then, it can be seen that the transportability of the developer is improved without deterioration of the toner contamination on the surface of the developer sleeve.

The present inventors have considered that this phenomenon occurs for the following reasons. First, (1) the reason why the developer transportability is improved when the ten-point average roughness Rz of the developer sleeve surface is increased will be described. Aluminum has a lower hardness than SUS. Therefore, when blasting is performed under the same conditions, the surface of the aluminum developer sleeve is blasted more deeply than the surface of the SUS developer sleeve. In fact,
The ten-point average roughness of the SUS developer sleeve surface of Experimental Example 3 (Comparative Example 3) was Rz = 3 μm, whereas the ten-point average roughness of the aluminum developer sleeve surface of Experimental Example 5 (Example 1-1). Rz is 10 μm, and the surface of the aluminum developer sleeve is rougher. As described above, since the surface of the aluminum developer sleeve of Experimental Example 5 (Example 1-1) has a larger surface roughness, that is, the height difference between the peaks and valleys of the irregularities on the surface of the developer sleeve is larger. It is considered that the frictional force between the developer and the surface of the developer sleeve was increased to improve the transportability of the developer.

In general, it is considered that increasing the value of the ten-point average roughness Rz on the surface of the developer sleeve makes it easier for the toner to be caught in the concave portions on the surface of the developer sleeve, and that the contamination of the developer sleeve becomes worse. As long as the surface of the developer sleeve is kept to some extent smooth using the glass beads or the like, there is not much problem. This is considered for the following reasons. As described above, when toner is embedded in small grooves enough to allow toner to enter and becomes difficult to move, when toner is most likely to fuse to the surface of the developer sleeve during long-term use. Conceivable. However, in the aluminum developer sleeve of Experimental Example 5 (Example 1-1), although the level difference of the unevenness on the surface was large and rough, the groove on the surface of the developer sleeve was subjected to the blast treatment with the shaped glass beads. Has a substantially spherical shape and is formed of relatively smooth grooves with few small jaggies. Therefore, the toner is not embedded in the groove, and is less likely to be fused.

Furthermore, as a result of a detailed study including the types of regular spherical particles used for the carrier and the blast particles, the ten-point average roughness Rz is defined as D / D, where D is the average particle diameter of the carrier.
It was found that the range of 6 ≦ Rz ≦ D / 2 was good for preventing the contamination of the developer sleeve and improving the transportability of the developer. The ten-point average roughness Rz of the developer sleeve surface is D /
In the case of 6 or more, the carrier is sufficiently caught by the irregularities on the surface of the developer sleeve, the frictional resistance between the developer and the developer sleeve is increased, and the transportability of the developer can be improved. However, if the ten-point average roughness Rz exceeds D / 2, the edge portion corresponding to the uneven portion on the surface of the developer sleeve becomes very sharp, which affects the formation of carrier spikes and consequently affects the image. Effect. Also, it is very difficult to manufacture such a developer sleeve. As described above, by adjusting the ten-point average roughness Rz, the transportability is improved without deteriorating toner contamination on the surface of the developer sleeve.

Next, the reason why (2) when the particles for blasting the developer sleeve are coarsened (the number of meshes is reduced), the transportability is improved will be described. Experimental example 4
Blasting with # 400 mesh regular glass beads (FGB # 400) of (Comparative Example 4) and Experimental Example 5
In comparison with the case of blasting with # 300 mesh regular glass beads (FGB # 300) of Example 1-1 (all of which are made of aluminum), Experimental Example 5 in which blasting was performed with # 300 mesh (implemented) In the case of Example 1-1), the transportability of the developer was improved. # 400 used for classification
The mesh and # 300 mesh are based on the standard mesh standard sieve standardized as a sieve for particle size measurement according to JIS Z8810.
7 μm, # 300 mesh corresponds to 50 μm. On the other hand, the average particle size of the magnetic carriers used in Experimental Examples 4 and 5 was 40 μm. From the above, the developer sleeve of Experimental Example 4 (Comparative Example 4) was blasted with spherical glass beads having a smaller diameter than the magnetic carrier.
The developer sleeve of Example 1-1 was blasted with spherical glass beads having a larger diameter than the magnetic carrier.

When the state of the magnetic carrier on the developer sleeve in each case is compared, when the magnetic carrier is blasted with spherical beads having a smaller diameter than the magnetic carrier, as shown in FIG. Cannot reach the depth of the spherical groove, and a gap is left between the magnetic carrier and the spherical groove on the developer sleeve. Therefore, the magnetic carrier cannot be securely caught in the spherical groove, and the magnetic carrier easily rolls on the groove on the developer sleeve. Therefore, the frictional resistance between the developer and the developer sleeve decreases, and the conveyance force of the developer sleeve decreases. On the other hand, when blasting is performed with spherical beads having a diameter larger than that of the magnetic carrier, the magnetic carrier can penetrate deep into the spherical groove on the developer sleeve as shown in FIG. There is no gap between the upper spherical grooves. Therefore, the magnetic carrier can be firmly caught in the spherical groove, and the magnetic carrier is hard to roll on the developer sleeve. Therefore, it is considered that the frictional resistance between the developer and the developer sleeve was increased, and the transportability of the developer sleeve was improved.

As described above, when the surface of the developer sleeve is blasted with the spherical beads having a diameter larger than that of the magnetic carrier, the transportability of the developer by the developer sleeve is improved. However, the advantage of blasting the surface of the developer sleeve with spherical beads having a diameter larger than that of the magnetic carrier is not limited to this, and the results in Table 1 show that the developer sleeve is improved with respect to contamination. this is,
It is thought to be due to the following reasons. When blasted with spherical beads smaller in diameter than the magnetic carrier,
As described above, as shown in FIG. 3, the magnetic carrier cannot enter the bottom of the spherical groove on the developer sleeve, and there is a gap between the magnetic carrier and the spherical groove on the developer sleeve. Will happen. Since the toner that has entered the gap cannot be scraped off by the magnetic carrier, the toner stays in the gap and tends to stay. As a result, the residual toner accumulates heat and is fused. On the other hand, when the surface of the developer sleeve is blasted with spherical beads having a diameter larger than that of the magnetic carrier, the magnetic carrier can penetrate to the bottom of the spherical groove on the developer sleeve as shown in FIG. There is no gap between the carrier and the spherical groove on the developer sleeve. Therefore, in the process of carrier circulation,
The toner adheres to the carrier and is carried, and the toner does not remain on the surface of the developer sleeve. As a result, contamination is less likely to occur.

Further, as a result of a detailed study including the type of carrier, etc., the developer sleeve was found to have an average diameter d (D ≦ d ≦ 10D) of not less than the average particle diameter D of the magnetic carrier and not more than 10 D
It has been found that the blast treatment with the regular spherical particles having the following characteristics is effective for preventing the contamination of the developer sleeve and improving the transportability of the developer. When the diameter d of the regular spherical particles is equal to or larger than the average particle diameter D of the magnetic carrier, as described above, the frictional resistance between the developer and the developer sleeve is increased, and the transportability of the developer is improved. Agent sleeve contamination is also reduced. However, the carrier forms ears in the developing part, and the distance between the ears varies depending on the magnetic force, the carrier diameter or the carrier magnetization. When a ferrite carrier is used, the carrier is arranged at intervals of about 10 times the carrier diameter. To form a magnetic brush. Therefore, if the diameter of the regular particles exceeds 10 times the carrier diameter, the ears of the magnetic brush become random, and the layer of the developer becomes uneven due to the unevenness, which affects the formed image. As described above, by adjusting the average diameter d of the regular spherical particles used for the blasting of the surface of the developer sleeve, the transportability of the surface of the developer sleeve is improved, and the contamination of the developer sleeve is further reduced.

According to the studies by the present inventors, (1) the ten-point average roughness Rz of the surface of the developer sleeve is in the range of D / 6 ≦ Rz ≦ D / 2, where D is the average particle diameter of the carrier;
(2) When the developer sleeve is blasted with regular spherical particles having an average diameter d of not less than D and not more than 10 D (D ≦ d ≦ 10 D) of the magnetic carrier, the surface of the developer sleeve It was found that the developer transportability was improved without worsening the toner contamination. However, in the above-mentioned experimental example, the above-mentioned (1), but not (2), which was not applied to (2), was subjected to the standard blast treatment of the surface of the aluminum tube of Example 4 (Comparative Example 4) with spherical glass beads of # 400 mesh. SUS of Experimental Example 3 (Comparative Example 3) which is applicable to the above-mentioned (2) but not applicable to (1).
A developer sleeve having a base tube subjected to regular blasting on the surface with # 300 mesh spherical glass beads can improve the transportability to some extent, but does not reach a level without any problem. However, there have been cases where problems such as a problem of transportability appear during long-term use. Therefore, with respect to the transportability, in order to obtain a good image stably for a long period of time, (1) the ten-point average roughness Rz of the surface of the developer sleeve is defined as D / 6 ≦ Rz, where D is the average particle diameter of the carrier. ≦ D / 2, and (2) the developer sleeve has an average particle diameter D of the magnetic carrier.
It is most desirable and necessary that the blast treatment be carried out with regular spherical particles having an average diameter d (D ≦ d ≦ 10D) of not less than 10D.

In this embodiment, only the developer sleeve made of aluminum has been described as the developer sleeve. However, the material of the developer sleeve is not limited to aluminum. If so, SUS or the like may be used. However, using aluminum has the following advantages. First, SUS is expensive, but if aluminum is used, the cost of the developer sleeve can be reduced. In addition, since aluminum is softer than SUS, glass beads collide with the surface of the developer sleeve during the blasting process. A developer sleeve which has a strong tendency to be eliminated and has high uniformity can be obtained.

Further, when an a (amorphous) -Si drum is used as a photosensitive drum of a high-speed machine, a heater is provided in the a-Si drum in order to prevent a flow phenomenon of image quality in the first use in the morning. There are many cases. If the developer sleeve is made of stainless steel, it is easily deformed by the heat of the drum heater because of its low thermal conductivity. On the other hand, if aluminum having a high thermal conductivity is used for the developer sleeve, thermal deformation by the drum heater can be avoided.

As described above, according to the present invention, the surface of the developer sleeve of the developing device has an average particle diameter d of not less than the average particle diameter D of the magnetic carrier and not more than 10D (D ≦ d ≦ 10
D) is blasted with the regular spherical particles, and the ten-point average roughness Rz of the treated surface is adjusted to the range of D / 6 ≦ Rz ≦ D / 2, where D is the average particle diameter of the carrier. Accordingly, when a two-component developer is used, the toner is prevented from being buried in the valley of the uneven portion on the surface of the developer sleeve by the carrier, and the occurrence of contamination of the developer sleeve due to the fusion of the toner is suppressed, and the development is performed. The developer transport amount of the developer sleeve to the region is also stabilized, thereby making it possible to guarantee the image quality stably for a long period of time.

Here, a method for measuring the average particle size of the carrier will be described. The method for measuring the average particle size of the carrier in the present invention is as follows. 1. Weigh about 100 g of sample to the nearest 0.1 g. 2. The sieve is 100 mesh to 400 mesh JI
S standard sieve (hereinafter simply referred to as “sieve”)
Stacked in the order of 0, 145, 200, 250, 350, 400, place a saucer on the bottom, put the sample in the top sieve and cover. 3. Using a vibrator, the number of horizontal turns is 285 ± 6 per minute.
And shake at 150 ± 10 times per minute for 15 minutes. 4. After sieving, weigh the iron powder in each sieve and tray to the nearest 0.1 g. 5. Calculated to the second decimal place by weight percentage, JIS-Z8
Rounded to the first decimal place by 401. At this time, the size of the sieve frame is 20 mm above the sieve surface.
0 mm, the depth from the top surface to the sieve surface is 45 mm,
Also, the sum of the weights of the iron powders in each part should not be less than 99% of the mass of the sample initially taken.

The average particle diameter is determined from the above-mentioned constant value on the particle size distribution side by the following equation.

(Equation 1)

<Embodiment 2> A developer sleeve whose surface has been roughened by cutting a SUS tube and then blasting the tube with spherical glass bead particles (FGB) is used. Although the example used was described, the surface subjected to blasting after cutting has a fine jagged state reflecting the roughness of the surface during cutting. When such minute jaggies are present, toner having a small particle size contained in the toner is caught and adhered to the minute grooves, and is likely to be in a fused state, so that the developer sleeve is likely to be contaminated. Therefore, as a method for solving such a problem, in this embodiment, the surface of the developer sleeve tube is roughened by performing diamond polishing after cutting and then blasting. When this developer sleeve was used, no developer sleeve contamination occurred. This is due to the fact that the diamond polishing almost eliminates the jaggedness at the time of cutting, and has been modified to a mirror-like surface state with no microscopic unevenness.

<Embodiment 3> In this embodiment, the surface of the surface-developed developer sleeve of Experiment 3 in Embodiment 1 is
It is characterized by electroless plating. As the electroless plating, for example, electroless Ni-P, electroless Ni-B plating, electroless Pd-P plating, or electroless Cr plating may be used, but it is not limited thereto.
The feature of electroless plating is that, in other plating, for example, electrolytic plating such as electrolytic Ni plating, plating is easily attached to an edge portion, and plating thickness is more uniform than that of plating. There is an advantage that the roundness caused by the collision can be maintained. In addition, there is an advantage that the rotation is good, plating can be performed even in a deep hole, and there is no unevenness on the surface, and a smoother surface can be obtained. From the above, by performing electroless plating, it is possible to eliminate fine jaggedness present on the surface after blasting while maintaining the surface shape after blasting by the regular spherical particles, and to achieve smoothness without microscopic irregularities. It is possible to obtain a surface. However, if the thickness of the plating is too large, the plating may be too smooth and the transportability of the developer sleeve may be reduced.
Therefore, the plating thickness is desirably 20 μm or less, which is a range in which the shape caused by the collision of the spherical particles can be maintained to some extent.

[0051]

As described above, according to the present invention,
The surface of the sleeve of the developing device is coated with the average particle diameter D of the magnetic carrier.
The blast treatment is carried out with regular spherical particles having an average diameter d (D ≦ d ≦ 10D) of not less than 10D and the ten-point average roughness Rz of the surface is D / 6, where D is the average particle diameter of the carrier.
≦ Rz ≦ D / 2, 2
When the component developer is used, the carrier prevents the toner from being buried in the valleys of the uneven portion on the surface of the developer sleeve, the occurrence of contamination of the developer sleeve due to the fusion of the toner is significantly reduced, and The developer conveyance amount of the developer sleeve is also stabilized, thereby making it possible to stably guarantee image quality for a long period of time.

According to the preferred embodiment of the present invention, the surface of the developer sleeve is polished with diamond and then subjected to blasting with regular spherical particles, so that micro-jagged portions on the surface of the developer sleeve are eliminated, and more effective. It is. According to a preferred embodiment of the present invention, the surface of the developer sleeve is blasted with regular spherical particles, and then the surface is further subjected to electroless plating. Lost and effective.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a developing device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an image forming apparatus using a developing device according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating an embodiment of the present invention;
FIG. 4 is an enlarged view of the surface of the developer sleeve of FIG.

FIG. 4 is a view for explaining one embodiment of the present invention;
FIG. 4 is an enlarged view of the surface of the developer sleeve of FIG.

[Explanation of symbols]

 1: developing device 3: developer sleeve 4: photosensitive drum 5: blade 6: toner supply tank 21: primary charger 22: light emitting element 23: transfer charger 24: transfer paper transport sheet 25: fixing device 26: cleaning device 27 : Transfer paper Y: Yellow M: Magenta C: Cyan K: Black

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Yuji Sakami 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H005 AA00 BA00 EA05 FA02 2H031 AC10 BA08 BA09 2H077 AD06 AD36 EA03 FA03 FA14 FA26

Claims (14)

[Claims] 1. An image forming apparatus comprising: means for forming an electrostatic latent image corresponding to an image information signal on an image carrier;
When the electrostatic latent image on the image carrier is developed using a two-component developer having a non-magnetic toner and a magnetic carrier to form a toner image, the two-component developer is carried to the developing area. In the developing device having the developer carrier to be conveyed, the surface of the developer carrier is an average satisfying the following relationship with respect to the average particle diameter D of the magnetic carrier in the two-component developer. Blasted with regular spherical particles having a diameter d, the ten-point average roughness Rz of the surface of the developer carrier is:
A developing apparatus characterized in that the average particle diameter D of the magnetic carrier is set to satisfy the following relationship: D / 6 ≦ Rz ≦ D / 2. 2. The developing device according to claim 1, further comprising electric field forming means for forming an alternating electric field between said image carrier and said developer carrier. 3. The developing device according to claim 1, wherein the surface of the developer carrying member is polished with diamond particles, and then the surface is blasted with regular spherical particles. 4. The developing device according to claim 1, wherein the surface of the developer carrying member is subjected to blasting with regular spherical particles, and then the surface is further subjected to electroless plating. 5. The developing device according to claim 1, wherein the material of the developer carrying member is aluminum or stainless steel. 6. The electroless plating according to claim 1, wherein the electroless plating is electroless Ni-P plating, electroless Ni-B plating, electroless Pd-P plating,
5. The developing device according to claim 4, wherein the developing device is electroless Cr plating. 7. The non-magnetic toner has an average particle diameter of 2 to 10.
The developing device according to claim 1, wherein the particle size is μm. 8. An image forming apparatus comprising: means for forming an electrostatic latent image corresponding to an image information signal on an image carrier;
The electrostatic latent image on the image carrier is developed by using a two-component developer having a non-magnetic toner and a magnetic carrier to form a toner image. In the method for producing a developer carrier to be conveyed to a developing area, the surface of the developer carrier is expressed by the following relationship with respect to the average particle diameter D of the magnetic carrier in the two-component developer: D ≦ d ≦ 10D Blasting with regular spherical particles having an average diameter d that satisfies the following relationship. The ten-point average roughness Rz of the surface of the developer carrier is expressed by the following relationship with the average particle diameter D of the magnetic carrier. A method for producing a developer carrier, wherein the method is adjusted to satisfy D / 6 ≦ Rz ≦ D / 2. 9. The method according to claim 8, wherein the regular spherical particles are glass beads, stainless steel spheres, or ceramic spheres. 10. The method according to claim 8, further comprising, before the step of blasting the surface of the developer carrying member with the regular spherical particles, polishing the surface of the developer carrying member with diamond.
Or a method for producing a developer carrier according to item 9. 11. The method according to claim 8, further comprising the step of performing electroless plating on the surface of the developer carrier after the step of blasting the surface of the developer carrier with regular spherical particles.
0. The method for producing a developer carrying member according to any one of items 0 to 10. 12. The method for producing a developer carrier according to claim 8, wherein the material of the developer carrier is aluminum or stainless steel. 13. The electroless plating method according to claim 1, wherein the electroless plating is performed using an electroless Ni—P
The method for producing a developer carrier according to claim 11, wherein the method is plating, electroless Ni-B plating, electroless Pd-P plating, or electroless Cr plating. 14. The non-magnetic toner having an average particle size of 2 to
The method for producing a developer carrier according to claim 8, wherein the thickness is 10 μm.