JPH0651618A - Developing device - Google Patents

Abstract

PURPOSE:To provide a developing device capable of stably obtaining an excellent image in long-term work. CONSTITUTION:In this developing device 20 carrying toner 6 as a one-component developer following the rotation of a developing sleeve 3, the surface of the developing sleeve 3 is roughened so as to form a large number of comparatively smooth recessed part areas, and the roughness of the surface is set within the range of 0.4mum-1.0mum in center line average surface roughness (Ra). Thus, the carrying capacity of the toner 6 on the developing sleeve 3 is enhanced, simultaneously, the quantity of the toner on the developing sleeve 3 and an electrostatic charging amount are properly kept as well and the toner 6 on the developing sleeve 3 is surely stuck to a photosensitive drum 1 so that the excellent image can be stably obtained in the long-term work, as well.

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.

[0002]

2. Description of the Related Art Conventionally, as a developing device, a roller as a toner carrier is rotatably provided at an opening in a toner hopper provided with an agitating member, and a blade as a regulating member is evenly pressured on the roller. The toner held on the surface of the roller is conveyed while the layer thickness of the toner is regulated by the blade, and the toner is directly used for developing the electrostatic latent image on the photoconductor, or a thin layer toner is used. It is known that the toner is once supplied to a developing sleeve, mixed with a carrier, and then used for developing.

For example, there is a developing device as disclosed in Japanese Patent Laid-Open No. 54-43038. In this developing device, an elastic blade made of rubber or metal which is a developer regulating means is brought into contact with a developing sleeve which is a developer carrying member, and a toner which is a developer is allowed to enter and pass through the abutting portion to develop the toner. A thin layer of toner is formed on the sleeve, and an electric charge (hereinafter referred to as tribo) due to frictional charging is applied to the toner at the contact portion.

In such a developing device, when a magnetic toner is used, if a magnet is provided in the developing sleeve, the magnetic force of the magnet can supply the toner onto the developing sleeve.

However, there is a problem that a new mechanical supply means is required to use the non-magnetic toner.

Therefore, the present applicant has proposed the developing device shown in FIG. 14 (see Japanese Patent Laid-Open No. 58-116559). In such a developing device, on the upstream side in the developing sleeve rotation direction from the contact portion between the elastic blade 4 and the developing sleeve 3,
A supply roller 5, which is a developer supply / separation unit, is arranged so as to contact the developing sleeve 3, and toner is supplied to the developing sleeve 3 and undeveloped toner on the developing sleeve 3 is peeled off. According to this, with a simple structure, high concentration,
It is possible to faithfully reproduce a solid black image of a wide area and always obtain a good image.

In addition, the developing sleeve of the conventional apparatus has irregular shaped blast particles (hereinafter referred to as horny powder particles) having sharp edges.
It has also been proposed to subject the one-component developer to an appropriate charged state and further stabilize the carrying capacity by subjecting the surface thereof to a roughening treatment by sandblasting with amorphous particles).

However, the grain size # 4 on the developing sleeve.
A surface-roughened development sleeve sand-blasted with irregular-shaped particles of No. 00 (standard of particle size according to JIS-R6001 "Abrasive"; hereinafter the same with respect to particle size) is used, and a non-magnetic one-component developer is used. When a toner was used and an image development durability test was conducted in a developing device in which an elastic blade and a supply roller were in contact with the developing sleeve, the following phenomenon occurred. That is, when the continuous copying operation is continued, the number of printed images is about 500.
The image density has decreased from the sheet position and fog has occurred.

In the developing device described above, when the toner on the entire circumference of the surface of the developing sleeve was removed, and then the developing sleeve was further cleaned with a solvent and image formation was performed, the image density was recovered.

Therefore, regarding the above phenomenon, first, the triboelectric charge amount (tribo) of the toner on the developing sleeve was measured.
It was found that the reduction of the tribo caused the image density to be lowered and the fog to be generated.

When the surface of the developing sleeve at this time was observed with an electron microscope or the like, it was possible to observe a state in which something was embedded in the concave and convex portions of the surface, especially the concave portions. Analysis revealed that the substance embedded in the recess was a resin binder in the toner components. Since the binder with which the concave portions are covered and the toner are both resin, contact between the resins occurs frequently, sufficient charging cannot be obtained, and tribo is reduced. In particular, it was found that the resin adhered strongly in the deep part of the recess and was blasted with the irregular particles, so that the sharpness of the shape further strengthened the adhesion of the resin.
It was also found that the toner was hardly scraped off by the supply roller in the deep and sharp portion of the recess.

The toner carried and conveyed by the developing sleeve in the above-described state is toner (resin embedded in the surface layer of the developing sleeve (or embedded in the recess) under the contact pressure between the elastic blade and the developing sleeve). ), The toner becomes unstable in the charged state (the amount of charge is low, or the opposite polarity is charged). As a result, when these toners contribute to the development in the developing section, there is a problem that a phenomenon of low density and fogging occurs.

Next, since it has been found that a resin having a sharp shape causes the resin to adhere to the surface of the developing sleeve, conversely, instead of using irregular particles for sandblasting, it is preferable to use a developing sleeve whose surface is made smooth by using regular particles. If so, the above problem was considered to be solved.

Therefore, image development and durability are achieved by using a developing sleeve that has been sandblasted using regular blast particles having a particle size of # 400 (hereinafter referred to as regular particles) having a smooth surface like granular powder particles. As a result (see Japanese Patent Application Laid-Open No. 57-116372), no resin adhered to the surface of the developing sleeve even during long-term operation, and good images could be obtained.

[0015]

However, in order to further improve the image quality, when a small particle size toner is used as the developer, the surface of the developing sleeve is formed with only a relatively large number of recessed areas which are relatively smooth. Even under the roughened condition, under the special condition, the following new phenomenon occurs.

When the surface roughness of the developing sleeve is less than 0.4 μm in terms of the center line average surface roughness (Ra), the image density was reduced by copying an original with a lot of white background with extremely low toner consumption in a low humidity environment. Immediately dropped.

The surface roughness (Ra) of the developing sleeve is 1.
When the grain size was made coarser than 0 μm, when the image was copied after being left for a long time in a high humidity environment, remarkable fog was generated on the image. Then, when the surface of the developing sleeve having the above phenomenon was observed, it was confirmed that the thickness of the toner layer on the sleeve surface was thin and the average tribo amount was measured, and it was considerably higher than the initial tribo value. This is because the roughness (Ra) of the surface of the developing sleeve is as small as less than 0.4 μm, so that the amount of toner conveyed is reduced, and as a result, the toner particles and the sleeve surface and the blade surface are separated from each other at the elastic blade contact portion. This is because the contact probability increases and the charge amount increases. In particular, when the toner has a small particle size, the above tendency is promoted, and as a result, the charge amount is remarkably increased, and
The flight rate of the toner to the electrostatic latent image carrier is reduced.

When the surface of the developing sleeve having the above phenomenon is observed, the thickness of the toner layer on the sleeve surface is large, and
When the average tribo amount was measured, it was confirmed to be considerably low. This is the opposite of the phenomenon, and since the surface roughness (Ra) of the developing sleeve is rougher than 1.0 μm, the amount of toner conveyed increases, which causes the elastic blade abutting portion to contact the sleeve surface and the blade surface. Has a low contact probability of, that is, toner particles having a small charge amount increase, and as a result, the toner having a low charge amount cannot faithfully fly to the electric field formed between the latent image carrier and the developing sleeve,
This causes so-called fog that adheres to the white background of the document.

The above phenomenon also occurs when a one-component magnetic toner is used as the developer. or,
The surface of the toner-bearing roll, which is disposed in the opening of the toner hopper, forms a thin layer of toner on the surface, supplies the toner layer to the developing sleeve, mixes the toner with the carrier, and then develops the toner. Regarding the roughness (Ra), the amount of toner adhered to the developing sleeve, the image density, and the fog, the same phenomenon as the above phenomenon occurs.

The first aspect of the present invention has been made in view of the above problems, and an object thereof is to increase the amount of the developer and the amount of charge on the developer carrier while enhancing the conveying ability of the developer carrier. By properly maintaining and surely adhering the developer on the developer carrier to the image carrier or the developer carrier,
It is an object of the present invention to provide a developing device capable of stably obtaining a good image even in long-term operation.

By the way, in the conventional developing device shown in FIG. 14, the elastic roller 5 having a fur brush structure is used, but in addition to this, a continuous foamed material such as polyurethane foam having a foamed skeleton structure is supplied to the toner. It is also generally known to be used as a roller. According to this, due to the appropriate unevenness of the surface of the open-cell foam, the toner is supplied to the developing sleeve 3 and the undeveloped toner is scratched like the fur brush structure. It can be taken well.

The above-described structure, that is, the structure in which the elastic roller 5 as the toner supply member is brought into contact with the developing sleeve 3 has the same operation and effect even when the one-component magnetic toner is used as the developer 6. is there.

In order to further improve the image quality, when a toner having a small particle diameter is used or when a toner having a low melting point is used as a developer for the purpose of low power consumption and quick start,
When a developing device using a fur brush or an elastic roller having an open-cell foam structure is repeated a large number of times, the following problems particularly occur in a high temperature and high humidity environment.

While the developing operation is repeated, the elastic roller gradually becomes inside the elastic roller (in the case of the fur brush, the air bubbles are in communication between the fibers, and in the case of the foamed foam, the air bubbles are in communication with each other). Toner becomes clogged, resulting in hardening of the elastic roller.

When this hardening occurs, the contact pressure of the elastic roller with respect to the developing sleeve becomes excessive, and the function of the elastic roller to rub the toner against the developing sleeve is too strong, so that the toner is fused to the developing sleeve and the toner Change (deteriorate) in the physical properties of the developing roller, the fog increases, and the driving torque of the developing sleeve and the elastic roller significantly increases.

Since the degree of toner clogging in the elastic roller tends to be uneven in the longitudinal direction of the roller, the function of the elastic roller such as applying and scraping toner to the developing sleeve is also uneven in the longitudinal direction. As a result, unevenness in image density occurs due to tribo of the toner layer on the developing sleeve and unevenness of the layer thickness.

Therefore, in order to eliminate the inconvenience caused by the hardening of the elastic roller, it has been proposed to adopt the following configuration.

(A) A rubber skin layer is provided on the surface of the open-cell foam.

(B) A foamed rubber having a single foam property is used.

However, if the structure (a) is adopted, that is, the structure in which the rubber skin layer is provided on the surface of the foamed foam, the contact area of the skin layer surface with respect to the surface of the developing sleeve is increased as compared with the foam. In addition to the problem of toner fusion to the developing sleeve and toner deterioration, the same as when the toner supply roller made of the open-cell foam is hardened because the function of rubbing the toner onto the developing sleeve is too strong. However, problems such as toner fusion to the skin layer itself occurred.

Further, in order to reduce the contact area, it is necessary to roughen the surface of the skin layer or mold it into a concavo-convex shape. Even with such a structure, the initial surface of the open-cell foam is formed. Compared with, the local pressure on the developing sleeve was still high (lacking flexibility like a foam), and the same problem could not be solved.

Next, when the roller is composed of the above-mentioned structure (b), that is, the foam is composed of a foam of a single foam, the toner is applied / scraped to the developing sleeve and an electric charge is imparted by the appropriate unevenness of the foam of the single foam on the roller surface. However, in this case, it is necessary to pay sufficient attention to the influential factors relating to the elastic roller so that the roller can be prevented from being hardened due to toner clogging.

According to experiments conducted by the present inventors, when an elastic roller made of foamed rubber having a single foam property is used as a supply roller for supplying toner by abutting on a developing roller, the function of the roller is sufficiently exhibited. The main influencing factors for this are the sliding contact width between the developing roller and the elastic roller, and the hardness of the elastic roller, and it is necessary to define these factors within an appropriate range.

However, conventionally, these factors have not been taken into consideration, so that the following inconvenience has occurred.

That is, if the sliding contact width is too wide, the driving torque is increased as in the case where the skin layer is covered, and the load on the developing roller and the toner becomes excessive and the toner on the developing roller is increased. It causes fusion and toner deterioration.

Further, if the sliding contact width is too narrow, the contact of the elastic roller with the developing roller tends to be uneven, resulting in unevenness in toner application and scraping to the developing sleeve of the elastic roller, and copying. Problems such as density unevenness may occur even on the image. Even if the sliding contact width is set to an appropriate range, if the hardness of the elastic roller is low, the low molecular weight component (oil content) in the roller will seep out, and this oil will develop at the sliding contact portion with the developing roller. It may adhere to the roller and contaminate the developing roller.

On the other hand, when the hardness is high, there arises a problem that the timing of occurrence of toner fusion and toner deterioration on the developing roller is advanced. These inconveniences similarly occur when the elastic roller made of foamed foam rubber is used as a regulating member for regulating the toner layer thickness on the developing roller.

Next, when the single-foam elastic roller is brought into contact with the photosensitive drum as a toner carrier and used as a developing roller for carrying out contact development, in addition to the sliding contact width and hardness, its surface shape is Will also be an important influencing factor. Usually, as shown in FIG. 15, the roller of this type has its surface processed by grinder polishing or the like in order to obtain a desired outer diameter, and as a result, the single-cell partition wall 11 on the surface is cut to form a protrusion. It has a shape having twelve.

The height and interval of the above-mentioned projecting partition walls 12 are important factors in terms of toner transportability and latent image visualization when a single foam foam is used as the developing roller. Is, of course, determined by the number of cells that make up the single-foam foam rubber. For example, when the number of cells is large, the height and interval of the protruding cells are reduced, and the toner transportability is reduced. Of the toner and the load on the toner at the contact portion of the photosensitive drum tending to increase, the degree of toner deterioration and fusion is increased. If the number of cells is small, on the contrary, the height and spacing of the protruding cells increase, so that the sliding contact traces of the protruding cells are likely to remain on the photosensitive drum sliding contact portion, and problems such as roughness on the image may occur. There was a case where it ended up.

The second invention has been made in view of the above problems. The object of the second invention is that it does not cause fusion of the developer to the developer carrier or deterioration of the developer even during long-term operation. An object of the present invention is to provide a developing device capable of forming a stable image with low torque.

According to experiments conducted by the inventors, the influencing factor δ for making the elastic roller composed of a single foam foam sufficiently exert its function is the penetration amount δ of the elastic roller into the developing sleeve. It is necessary to specify the factor within an appropriate range.

Here, the penetration amount δ (mm) is expressed by the following equation.

[0043]

## EQU1 ## δ = 1/2 (α + β) -x where α: diameter of developing sleeve (mm) β: diameter of elastic roller (mm) x: axial distance between developing sleeve and elastic roller (mm) In the past, the above-mentioned factors were not taken into consideration, so that the following inconvenience occurred.

That is, when the penetration amount δ is too large, the penetration amount δ when an elastic roller made of an open cell foam is used.
Even within the appropriate range of the above, since the foam having a single foam has a higher hardness than the foam having a continuous foam, the contact pressure of the elastic roller to the developing sleeve and the toner becomes excessive, and the developing roller moves to the developing sleeve. The function of rubbing the toner is too strong, which causes fusing of the toner on the developing sleeve and increase of fog due to change (deterioration) of physical properties of the toner, and the driving torque of the developing sleeve and the elastic roller is remarkably increased.

When the amount of penetration is too small, the elastic roller is liable to be unevenly contacted with the developing sleeve in the longitudinal direction, so that toner is applied to the developing sleeve of the elastic roller.
This is not preferable because unevenness is caused in the stripping and density unevenness in the longitudinal direction is caused on the image.

The third invention has been made in view of the above problems, and an object thereof is to apply the developer to the developer carrying member and peel off the undeveloped developer satisfactorily and stably. It is possible to prevent the generation of defective images such as image density unevenness and fog that occur when the amount of penetration of the elastic roller into the developer carrying member is inappropriate, and it is possible to stably obtain good images for a long period of time. To provide a developing device.

[0047]

[Means for Solving the Problems] To achieve the above object,
According to a first aspect of the present invention, a regulating member is brought into pressure contact with a developer carrying member disposed in an opening of a one-component developer accommodating container provided with a stirring member so as to be endlessly movable, and the developing member is regulated by the regulating member. In a developing device that conveys a one-component developer in the one-component developer accommodating container with the movement of the carrier, a relatively smooth large number of recessed areas are formed on the surface of the developer carrier. It is characterized in that the surface is roughened and the surface roughness is set in the range of 0.4 μm to 1.0 μm in terms of center line average surface roughness (Ra).

A second aspect of the invention is a developing device in which a rotatable elastic roller made of a single-foam foam rubber for supplying a one-component developer to a developer carrier is brought into sliding contact with the developer carrier. The sliding contact width between the developer carrying member and the elastic roller is set within a range of 2.0 mm to 6.0 mm.

Further, the third invention is a developing device in which a rotatable elastic roller made of a single-cell foam rubber for supplying a one-component developer to a developer carrier is slidably contacted with the developer carrier. The amount of penetration of the elastic roller into the developer carrying member is set within a range of 0.3 mm to 1.5 mm.

[0050]

According to the first aspect of the present invention, the amount of developer and the amount of charge on the developer carrier can be properly maintained while the ability of transporting the developer on the developer carrier is improved. By reliably adhering the developer of (1) to the image bearing member or the developer bearing member, a good image can be stably formed even in a long-term operation.

Further, according to the second aspect of the invention, a good and stable image can be formed with a low torque without causing fusion of the developer to the developer carrier or deterioration of the developer even during long-term operation. .

Further, according to the third aspect of the invention, the application of the developer to the developer carrying member and the stripping of the undeveloped developer can be performed satisfactorily and stably, and the elastic roller can be applied to the developer carrying member. A good image can be stably obtained for a long period of time by preventing generation of a defective image such as image density unevenness or fog that occurs when the amount of penetration is inappropriate.

[0053]

【Example】

[First Invention] An embodiment of the first invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a sectional view of a developing device according to the present invention. In FIG. 1, reference numeral 1 denotes a photosensitive drum as an image carrier which rotates in the direction of arrow a. The photosensitive drum 1 is, for example, a so-called xerographic photoreceptor on which an electrostatic latent image is formed by the Carlson process, Japanese Patent Publication No. S42.
No. 23910, a photoreceptor having an insulating layer on the surface on which an electrostatic latent image is formed by the NP process, an insulator on which a latent image is formed by an electrostatic recording method, and an insulation on which an electrostatic latent image is transferred by a transfer method. A member on which an electrostatic latent image (or potential latent image) or a magnetic latent image is formed and held by a body or other appropriate method is used.

A developing device 20 according to the present invention is arranged opposite to the photosensitive drum 1. The developing device 20 includes a developer supply container (hereinafter simply referred to as a container) 2 and a developer carrier. Developing sleeve 3, an elastic blade 4 as a developer regulating means, and a supply roller 5 as a developer supply / separation means.
And a toner stirring member 8.

The container 2 has an opening 2a extending in the longitudinal direction of the developing device 20 (direction perpendicular to the paper surface of FIG. 1), and the developing sleeve 3 is arranged in the opening 2a. .

The developing sleeve 3 is made of a non-magnetic material such as aluminum and has a surface described later.
In FIG. 1, the developing sleeve 3 has a right substantially semi-peripheral surface projecting into the container 2 and a left substantially semi-peripheral surface exposed to the outside of the container 2 and is rotatably rotatably laid horizontally. , Is driven to rotate in the direction of arrow b in the figure. The exposed surface of the developing sleeve 3 to the outside of the container 2 faces the surface of the photosensitive drum 1 with a small gap therebetween. The developing sleeve 3 is not limited to the cylindrical body (sleeve), and may be an endless belt that is rotationally driven, a conductive rubber roller, or the like.

The supply roller 5 is disposed behind the developing sleeve 3 so as to rotate in sliding contact with the sliding contact portion S on the surface of the developing sleeve 3 projecting into the container 2. The supply roller 5 rotates in the same direction as that of the developing sleeve 3 to supply the toner 6 as a developer to the developing sleeve 3, and also makes elastic contact with the developing sleeve 3 to separate the toner 6 on the developing sleeve 3. Excuse me.

Further, the elastic blade 4 is arranged so as to abut on the developing sleeve 3 at the abutting portion T on the downstream side of the sliding contact portion S between the supply roller 5 and the developing sleeve 3 in the rotation direction of the developing sleeve 3. The contact portion T regulates passage of the toner 6 on the developing sleeve 3.

Thus, in the present embodiment, the stirring member 8
The toner 6 supplied near the developing sleeve 3 by the rotation of the supplying roller 5 is conveyed to the sliding contact portion S of the supplying roller 5 and adhered onto the developing sleeve 3, and then the elastic blade 4 and the developing sleeve 3 are separated from each other. It enters the contact portion T and is carried on the surface of the developing sleeve 3.

Further, when the toner 6 passes through the contact portion T between the elastic blade 4 and the developing sleeve 3, the toner 6 is brought into sliding contact with the surface of the developing sleeve 3 by the elastic blade 4 and is frictionally charged. In this way, the toner 6 can receive sufficient triboelectrification.

The toner 6 which has been sufficiently frictionally charged as described above passes through the contact portion T and is formed as a thin toner layer on the developing sleeve 3, and opposes the photosensitive drum 1 on the developing sleeve 3. It is carried to the developing section F.

In the developing section F, part of the toner 6 is consumed in the developing operation, and the other part is collected from the lower part of the developing sleeve 3 as the developing sleeve 3 rotates. The recovery member is provided with a seal member 7, and the seal member 7 is
While not being developed, the toner 6 is allowed to pass into the container 2, and the toner 6 in the container 2 is prevented from leaking from the lower portion of the container 2.

The collected toner 6 on the developing sleeve 3 is scraped off by elastic contact at the sliding contact portion S between the supply roller 5 and the developing sleeve 3. Then, most of the scraped off toner 6 is conveyed as the supply roller 5 rotates, mixes with the toner 6 in the container 2, and the charge of the charged toner 6 is dispersed. At the same time, new toner 6 is supplied onto the developing sleeve 3 and the toner 6
Is again tribo-applied and thinned at the contact portion T between the elastic blade 4 and the developing sleeve 3, and is conveyed to the developing portion F.

Since the undeveloped toner 6 on the developing sleeve 3 is scraped off in this manner, the toner 6 on the developing sleeve 3 is replaced, and the excessive charging of the toner 6, that is, the charge-up is prevented.

Now, the developing sleeve 3 will be described in detail.

In this embodiment, the surface shape of the developing sleeve 3, which is a toner carrier, is roughened so as to have a number of relatively smooth recessed areas, and the surface roughness is the center line average. Surface roughness (Ra) 0.4 μm to 1.0
It is in the range of μm.

The present inventors changed the center line average surface roughness (Ra) of the surface of the developing sleeve 3 and examined the relationship between the toner conveyance amount and average tribo amount by the developing sleeve 3 and the image density and fog. , Ra is 0.4 μm to 1.0 μ
Within the range of m, the developing sleeve 3 can be used even for long-term use.
It has been found that the above toner transport amount and average tribo amount are maintained at appropriate values, and good images can be formed.

2 and 3, Ra is 0.3 μm and 0.6.
7 shows experimental results such as the toner conveyance amount and average tribo amount with respect to the number of durable sheets in the case of μm and 1.2 μm.
As is clear from these figures, when Ra is 0.6 μm, both the toner conveyance amount and the average tribo amount are stable with respect to long-term operation, and the fluctuations as in other cases are small.

Next, the operation of this embodiment configured as described above will be described.

The toner 6 conveyed to the vicinity of the developing sleeve 3 by the supply roller 5 enters the contact portion T between the developing sleeve 3 and the elastic blade 4 as the developing sleeve 3 rotates. At this time, the toner 6 is rubbed against the relatively smooth concave portion of the developing sleeve 3 and the surface of the blade 4 to give a tribo, and the pressure of the elastic blade 4 is applied by an appropriate conveying force of the convex portion having a raised shape. Get out of the bottom. Here, since the developing sleeve 3 is roughened so that the surface roughness Ra thereof falls within the range of 0.4 μm to 1 μm, an appropriate amount of conveyance and tribo with respect to the toner layer on the developing sleeve 3 are provided. Grants are maintained over the long term.

When the surface roughness Ra of the developing sleeve 3 is out of the above range, for example, when Ra is below the lower limit,
The decrease in the toner conveying force on the developing sleeve 3 reduces the amount of the toner 6 used for development, and the probability of applying tribo to the toner 6 at the contact portion T between the developing sleeve 3 and the elastic blade 4 is increased. This increase increases the mirroring power with respect to the developing sleeve 3, and the flying rate of the toner 6 at the developing portion F decreases, resulting in a decrease in image density. Further, since the mirroring power is increased, it becomes difficult to scrape off the toner 6 which has not been developed by the supply roller 5.

On the other hand, when Ra exceeds the upper limit,
Since the toner carrying force on the developing sleeve 3 increases, the thickness of the toner layer on the developing sleeve 3 increases, and tribo is imparted at the contact portion T between the developing sleeve 3 and the elastic blade 4,
A difference occurs between the upper layer and the lower layer of the toner layer on the developing sleeve 3, and especially the intermediate layer has a lower contact probability with the surface of the developing sleeve 3 and the elastic blade 4, so that the charge amount is remarkably reduced, and as a result, fog on an image is generated. Will appear.

Next, an experimental example conducted under the following conditions based on this embodiment will be described.

<Experimental example> In this experimental example, an aluminum developing sleeve having a diameter of 16 mm was used, and the surface of the developing sleeve was grained.
Blasted with regular particles such as glass beads of 600 (particle size standard is JIS-R6001 "abrasive"),
A large number of relatively smooth recesses were formed. The surface center line average roughness (Ra) of the developing sleeve 3 at this time was 0.6 μm.

Next, as the material of the elastic blade, for example, rubber having JIS hardness of 40 ° to 80 °, preferably hardness of 5
Those of 0 ° to 70 ° are good for stable formation of a thin developer layer, and in this experiment, 30 parts of dry silica was added as a filler to a silicon HTV rubber having a hardness of 60 °. Then, the end portion of the elastic blade is urged to come into contact with the developing sleeve.

Here, the end portion of the elastic blade means
It is the tip of the elastic blade, the vicinity including the tip, or the tip not including the tip. Further, the set value of the pressing force of the elastic blade against the developing sleeve (the linear pressure in the generatrix direction of the developing sleeve) is preferably 1 g / cm to 100 g / cm, and in this experimental example, it was set to 10 g / cm.

Further, as the material of the supply roller, a sponge roller having a skeleton structure with a low degree of foaming (high density) is preferable. In this experimental example, a urethane foam having a thickness of 5 mm (a density of 0.025 g / cm ³ ) was wound around a core rod. The sponge roller softly contacts the developing sleeve, but the contact width is 1 mm to 10 m.
m is effective and is 4 mm in this experimental example. In order to improve the peeling of the undeveloped toner on the developing sleeve,
It is preferable that the peripheral speed of the sponge roller and the peripheral speed of the developing sleeve have a difference, and the relative speed of the sponge roller with respect to the developing sleeve is 5 mm / sec to 600 mm / se.
c is effective, and in this experimental example, it was set to 100 mm / sec.

Further, as the toner, a toner powder comprising a copolymer of styrene / acrylic resin and styrene-butadiene resin and a pigment and having an average particle diameter of 12 μm and 1.4% of colloidal silica is externally added.

As the developing method in this experimental example, for example, the method described in JP-B-58-32375, that is,
A so-called non-contact developing method is used in which an alternating current with a direct current superimposed is applied between the photosensitive drum and the developing sleeve to transfer the thin layer toner on the developing sleeve to an electrostatic latent image on the photosensitive drum in an image form. I was there. Alternatively, a contact development method may be used.

The developing device having the above-mentioned structure is incorporated in an FC-1 copying machine manufactured by Canon Inc., and the bias power source has a frequency of 1800 Hz and a peak / peak voltage of 1200 V.
AC voltage of -300V superimposed on the AC voltage, the surface potential of the latent image on the photosensitive drum is -600V in the dark area,
The light portion was set to -1500 V, the distance between the developing sleeve and the photosensitive drum was set to 200 μm, and development was performed by non-contact development.

As a result, about 30 μm is left on the developing sleeve.
Was obtained, and the charge amount of this layer was measured by the blow-off method. The charge amount was +15 μc / g. This charge amount is a value sufficient to obtain a good image.

The obtained image was a good image with a reflection density of 1.3.

Further, when 2,000 sheets of images were continuously formed, the charge amount of the toner was 15 μc / g to 20 μm.
It was possible to obtain a good image without sleeve ghost and density reduction until the final image formation, while maintaining c / g.

Further, when development was performed using a toner of the same kind as the above-mentioned toner and a small diameter of 8 μm in average diameter in a low humidity environment, the triboelectric charge amount of the toner increased abnormally up to the formation of 1000 images. Not, electric charge +18 μc / g to +
The image density was maintained at 22 μc / g, and an image was obtained in which the density did not decrease and fogging did not occur.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. Incidentally, FIG. 4 is an enlarged sectional view of the surface of the developing sleeve.

In this embodiment, as the surface material of the developing sleeve 3 which is a developer carrying member, a resin in which conductive fine powder such as carbon is dispersed is used. With such a configuration, the resin layer 9 has a smooth concave region and the conductive fine powder portion 10
In this case, the undulating convex portions are respectively formed and the surface roughness Ra of the developing sleeve 3 is set to 0.4 μm to 1.0 μm, and the same effect as that of the first embodiment described above can be obtained.

If the resin material is one whose charging polarity is opposite to the normal charging polarity of the toner particles, the force of applying tribo from the surface of the developing sleeve 3 to the toner is improved, and high humidity is obtained. It is effective under the environment. In this embodiment, the resin layer 9 on the surface of the sleeve 3 is made of Teflon resin for positively charged styrene-acrylic toner.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. 5 is a sectional view of the developing device according to the third embodiment.

In this embodiment, the toner supply roller 11 shown in FIG. 5 is used as the developer carrying member.

Thus, the developing device according to the present embodiment is a two-component developing device, and the toner supply roller 11 is rotatably arranged in the opening 2b of the hopper 2A for accommodating the one-component non-magnetic toner 6. There is. The toner supply roller 11 has an elastic blade 4 that abuts the toner 6 sent by the toner stirring member 8 in the hopper 2A on the roller 11.
The toner 6 by the electric field formed between the roller 11 and the developing sleeve 3 while being regulated by the developing sleeve 3.
The toner 6 is mixed with the magnetic carrier 12 existing in the vicinity of the developing sleeve 3 and agitated to serve for development.

In this structure, the surface of the toner supply roller 11 is roughened so as to have a large number of recessed areas which are relatively smooth as in the first and second embodiments.
Moreover, the surface center line average roughness (Ra) is 0.4 μm or more.
By setting the thickness within the range of 1.0 μm, the transport amount of the toner 6 to the developing sleeve 3 can be stably maintained for a long period of time. [Second Invention] An embodiment of the second invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 6 is a schematic configuration diagram of a developing device 20 according to the first embodiment. In FIG. 6, reference numeral 2 is a developing container containing a non-magnetic toner 6 which is a one-component developer. The developing device 20 is provided with a developing sleeve 3 that is installed opposite to the photosensitive drum 1, which is an image bearing member that rotates in the direction of the arrow a, inside the developing container 2, and the electrostatic latent image toner on the photosensitive drum is provided. The image is developed and visualized.

In the developing container 2, an elastic blade 4 as an elastic restricting member is provided above the developing sleeve 3, and a position upstream of the elastic blade 4 in the rotational direction of the developing sleeve 3. Is provided with an elastic roller 5 made of a single foam foam rubber as a toner supply roller.

The elastic blade 4 is attached so as to incline downward toward the upstream side of the developing sleeve 3 in the rotational direction, and is abutted against the outer peripheral surface of the upper portion of the developing sleeve 3 in the rotational direction. ing.

Further, the elastic roller 5 is the developing sleeve 3
Is abutted on the opposite side of the photosensitive drum 1 and is rotatably supported.

Thus, in the developing device 20, the elastic roller 5 rotates in the direction of the arrow c in the figure to carry the toner 6 and supply the toner 6 in the vicinity of the developing sleeve 3, thereby developing the developing sleeve 3 and the elastic roller 5. The toner 6 on the elastic roller 5 is rubbed against the developing sleeve 3 at the contact portion (nip portion) where and contact with each other, so that the toner 6 adheres to the developing sleeve 3. The operation of the elastic roller 5 at the contact portion with the developing sleeve 3 will be described in detail later.

After that, as the developing sleeve 3 rotates, the toner 6 attached to the developing sleeve 3 is removed by the elastic blade 4.
And a developing sleeve 3 at a contact portion between them, and when passing therethrough, they are rubbed by both the surface of the developing sleeve 3 and the elastic blade 4 and sufficiently frictionally charged.

The toner 6 charged as described above is
The thin film is formed on the developing sleeve 3 through the abutting portion between the elastic blade 4 and the developing sleeve 3, and a small gap is formed between the photosensitive drum 1 and the photosensitive drum 1, and the toner is conveyed to the developing portion. Then, in the developing section, by applying an alternating voltage, in which a direct current and an alternating current are superposed, as a developing bias between the developing sleeve 3 and the photosensitive drum 1, the toner 6 on the developing sleeve 3 becomes an electrostatic latent image on the photosensitive drum 1. Corresponding to the above, and is adhered to the electrostatic latent image and developed as a toner image to be visualized.

By the way, the toner 6 remaining on the developing sleeve 3 without being consumed for development in the developing section is collected in the developing container 2 from below the developing sleeve 3 as the developing sleeve 3 rotates. A seal member 7 is provided at the toner collecting portion of the developing container 2. The seal member 7 allows passage of the toner 6 remaining on the developing sleeve 3 into the developing container 2, and prevents the toner 6 in the developing container 2 from leaking from the lower portion of the container 2.

Thus, the toner 6 collected in the developing container 2 is peeled off from the developing sleeve 3 by the elastic roller 5 at the contact portion with the developing sleeve 3. At the same time, the new toner 6 is supplied onto the developing sleeve 3 by the rotation of the elastic roller 5, and the new toner 6 is again supplied to the developing sleeve 3.
Is conveyed to the contact portion between the developing sleeve 3 and the elastic blade 4 with the rotation of.

On the other hand, most of the peeled toner 6 is
As the elastic roller 5 rotates, it is conveyed into the toner 6 in the developing container 2 and mixed with the toner 6, and the charge of the toner 6 that has been peeled off is dispersed.

By the way, a moderately rough surface is formed on the surface of the developing sleeve 3, whereby the probability of rubbing between the surface of the developing sleeve 3 and the toner 6 is increased, and the transportability of the toner 6 is improved. To be

The uneven surface of the developing sleeve 3 has a surface roughness R
It is obtained by subjecting the surface of the developing sleeve 3 to sandblasting with irregular-shaped alundum abrasive grains or sandblasting with regular-shaped glass beads so that z is 1 μm to 10 μm. Alternatively, a convex rough surface is formed on the surface of the developing sleeve 3 using conductive particles such as metal oxide particles, graphite, or carbon that can independently form a convex, and the convex rough surface is formed. The particles may be bound with a binding resin such as a phenol resin or a fluororesin to form recesses on the surface of the binding resin, thereby obtaining a rough surface on the surface of the developing sleeve 3.

In this embodiment, as the developing sleeve 3, an aluminum sleeve having a diameter of 16 mm is used as a base,
The surface of this was subjected to a blast treatment with regular glass beads (# 600) to have a surface roughness Rz of about 3 μm.

The elastic blade 4 is in contact with the developing sleeve 3, and the toner 6 which has entered between the elastic blade 4 and the developing sleeve 3 is applied onto the developing sleeve 3 to form a thin layer of the toner 6. The elastic blade 4 is made of silicon if
Rubber member such as urethane (JIS A has a hardness of 40 °
Is about 90 °), and a part of the surface of the elastic blade 4 facing the developing sleeve 3 abuts in a surface contact to press the developing sleeve 3 under pressure.

The contact pressure of the elastic blade 4 to the developing sleeve 3 in the present invention is preferably 1 g / cm to 100 g / cm in linear pressure in the generatrix direction of the developing sleeve 3, and in this embodiment, the elastic blade 4 has a hardness of 60. Use a silicon rubber blade with a thickness of 1.0 mm and 10g / c
It was brought into contact with the developing sleeve 3 with a linear pressure of m.

The linear pressure is measured by stacking three thin plates of known friction coefficient, inserting them into the contact portion of the elastic blade 3, and pulling out the central thin plate with a spring balance. The linear pressure was converted from.

The non-magnetic toner 6 is used as a non-magnetic one-component developer, and is made of styrene resin, acrylic resin,
It is formed by dispersing a pigment such as carbon in various thermoplastic resins such as polyethylene resin. In this embodiment, the toner 6 is styrene resin / acrylic resin and styrene.
Average particle size consisting of butadiene resin copolymer and pigment 1
A toner powder of 2 μm to which 1.0% of colloidal silica was externally added was used.

Next, the elastic roller 5 as the toner supply roller made of the single-foam foam rubber in this embodiment will be described in detail.

The elastic roller 5 for toner supply in this embodiment has a metal cored bar 51 as a support shaft, and a silicon rubber, EPDM rubber, CR rubber, or the like, on the outer side of which a wall surface of the air bubble portion is adjacent to the air bubble portion. It is a single foam foam that does not communicate with each other and has a roller shape. Its hardness is Asker C, 300.
It is set in the range of 8 ° to 25 ° with g load. The elastic roller 5 is slidably contacted with the developing sleeve 3 by the width W.
Of 2.0 mm to 6.0 mm, and the elastic roller 5 is rotationally driven in the direction of arrow c in the figure.

The inventors of the present invention changed the sliding contact width W between the elastic roller 5 and the developing sleeve 3 and the hardness of the elastic roller 5,
The copying operation is repeated many times, the toner is fused on the developing sleeve 3, the developing sleeve 3 is contaminated by the low molecular weight component (oil) exuding from the elastic roller 5, and the elastic roller 5
As a result of examining the relationship between the contact unevenness and the density unevenness on the image, the sliding contact width W is in the range of 2.0 mm to 6.0 mm, and the elastic roller 5 has a hardness of 8 ° to 25 ° (Asker C,
It was found that within a range of (with a load of 300 g), a good image can be formed with a low driving torque even for long-term use.

FIG. 7 is a graph showing the above relationship. Figure 7
Is the hardness of the elastic roller 5 on the horizontal axis and the sliding contact width W on the vertical axis, and due to toner fusion on the developing sleeve 3, toner deterioration, a large torque region, and oil seepage from the elastic roller 5. The relationship between the contaminated area of the developing sleeve 3 and the image density uneven area due to contact unevenness or the like is shown. In FIG. 7, a region surrounded by three lines is a region where a proper image can be formed, and if it deviates from the region, an adverse effect occurs for the reason described in the conventional example.

In this embodiment, the elastic roller 5 has a metal core 51 having an outer diameter of 4 mm and a silicon single-foam foam rubber having a hardness of 10 ° (Asker C, 300 g load) and a roller thickness of 4 mm. The coated roller having an outer diameter of 12 mm was used, and the sliding contact width W of the elastic roller 5 with respect to the developing sleeve having an outer diameter of 16 mm was set to 4.0 mm. Further, the elastic roller 5 has a relative speed with respect to the developing sleeve 3, and its range is preferably 5 mm / sec to 200 mm / sec, and in this embodiment, it was set to 80 mm / sec.

The apparatus as described above is manufactured by Canon Inc. F
Built in a C-1 copying machine, a bias power source having a frequency of 1800 Hz and a peak-to-peak voltage of 1200 V superimposed with a DC of -300 V was used, and the surface potential of the latent image on the photosensitive drum 1 was -600 V in the dark area. The non-contact development was carried out by setting the light section to -150 V and the distance between the developing sleeve 3 and the photosensitive drum 1 to 200 μm.

As a result, about 30 μm is left on the developing sleeve 3.
A uniform toner coating layer of m was obtained, the charge amount of Toner 6 was a good value of +15 μc / g, and the image was a good image with a reflection density of 1.3. Further, when 2000 sheets of images are continuously formed, the developing sleeve 3 is not contaminated due to the fusion of the toner 6 onto the developing sleeve 3 or the exudation of oil until the final image formation. ,
A good image without density unevenness, ghost, density reduction, and fog could be obtained with low driving torque.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. 8 is a sectional view of the developing device according to the second embodiment.

In this embodiment, an elastic roller made of foamed foam rubber is used as the regulating roller 8 for regulating the thickness of the toner layer on the developing sleeve 3, and the regulating roller 8 makes sliding contact with the developing sleeve 3. The width W is set in the range of 2.0 mm to 6.0 mm, and the hardness thereof is 8 ° to 25 ° (Asker C, 3
(With a load of 00 g). By setting the contact width W and the hardness of the regulation roller 8 in the above range,
It is possible to maintain a uniform and proper toner layer thickness on the developing sleeve 3 without causing contamination of the developing sleeve 3 due to fusing of the toner 6 on the developing sleeve 3 and seeping of oil from the regulation roller 8. Become.

In the case of the present embodiment, the sliding width W and the hardness of the regulating roller 8 are within the above ranges so that the toner 6 can be appropriately charged at the sliding contact portion of the regulating roller 8 with the developing sleeve 3. In addition, it is preferable that the charging polarity is set to the inside and the charging polarity is opposite to the normal charging polarity of the toner 6.

For the purpose of improving the scraping force of the undeveloped toner 6 on the developing sleeve 3, in addition to the regulating roller 8, another elastic roller made of foamed foam rubber is applied onto the developing sleeve 3. You may contact.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. 9 is a sectional view of the developing device according to the third embodiment.

In this embodiment, the elastic roller made of foamed rubber having a single foam is used as the developing roller 9 by dispersing conductive fine powder such as carbon therein, and the developing roller 9 is an image carrier. And the electrostatic latent image on the photosensitive drum 1 is developed as a toner image and visualized.

The appropriate range of the sliding contact width W and the hardness of the developing roller 9 at this time is the same as in the first and second embodiments,
In addition to these, the number of cells per unit length of the developing roller 9 which determines the surface property of the developing roller 9 is set to 100 to 300 cells / inch, and the surface is treated by grinder polishing or the like to form a single-cell partition wall. By forming the protrusions, it is possible to prevent the fusion of the toner 6 to the photosensitive drum 1 from being promoted, and a good image without a rubbing streak on the surface of the photosensitive drum 1 due to the protruding partition wall on the surface of the developing roller 9 is formed. Can be formed. [Third Invention] An embodiment of the third invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 10 is a schematic structural view of a developing device according to the first embodiment.

In FIG. 10, reference numeral 2 denotes a developing container containing a non-magnetic toner 6 as a one-component developer, and the main developing device 20 opposes the photosensitive drum 1 which is an image carrier rotating in the direction of the arrow a. The developing sleeve 3 installed as a container is provided inside the developing container 2, and the electrostatic latent image on the photosensitive drum 1 is developed and visualized as a toner image.

The elastic blade 4 is provided so as to be inclined downward toward the upstream side of the developing sleeve 3 in the rotational direction, and is in contact with the upper outer peripheral surface of the developing sleeve 3 in the rotational direction.

The elastic roller 5 is in contact with the portion of the developing sleeve 3 opposite to the photosensitive drum 1 and is rotatably supported.

Thus, in the developing device 20, the elastic roller 5 rotates in the direction of the arrow in the drawing to carry the toner 6 and supply the toner 6 to the vicinity of the developing sleeve 3, so that the developing sleeve 3 and the elastic roller 5 are separated from each other. At the abutting portion (nip portion) that abuts, the toner 6 on the elastic roller 5 is rubbed against the developing sleeve 3, so that the toner 6 adheres to the developing sleeve 3.

After that, as the developing sleeve 3 rotates, the toner 6 attached on the developing sleeve 3 is removed by the elastic blade 4.
And a developing sleeve 3 at a contact portion between them, and when passing therethrough, they are rubbed by both the surface of the developing sleeve 3 and the elastic blade 4 and sufficiently frictionally charged.

The toner 6 charged as described above is
The elastic blade 4 and the developing sleeve 3 come out of the contact portion, form a thin layer on the developing sleeve 3, form a minute gap with the photosensitive drum 1, and are conveyed to the opposing developing portion. Then, in the developing section, by applying an alternating voltage, in which a direct current and an alternating current are superposed, as a developing bias between the developing sleeve 3 and the photosensitive drum 1, the toner 6 on the developing sleeve 3 becomes an electrostatic latent image on the photosensitive drum 1. Corresponding to
The electrostatic latent image adheres to the electrostatic latent image and is developed as a toner image to be visualized.

By the way, the toner 6 remaining on the developing sleeve 3 without being consumed for development in the developing section is collected in the developing container 2 from below the developing sleeve 3 as the developing sleeve 3 rotates. A seal member 7 is provided at the toner collecting portion of the developing container 2. Seal member 7
Is a developing container 2 for the toner 6 remaining on the developing sleeve 3.
The toner 6 in the developing container 2 is prevented from leaking from the lower portion of the container 2 while allowing the toner to pass through the inside.

Thus, the toner 6 collected in the developing container 2 is peeled off from the developing sleeve 3 by the elastic roller 5 at the contact portion with the developing sleeve 3. At the same time, the new toner 6 is supplied onto the developing sleeve 3 by the rotation of the elastic roller 5, and the new toner 6 is again supplied to the developing sleeve 3.
Is conveyed to the contact portion between the developing sleeve 3 and the elastic blade 4 with the rotation of.

On the other hand, most of the peeled toner 6 is
As the elastic roller 5 rotates, it is conveyed into the toner 6 in the developing container 2 and mixed with the toner 6, and the charge of the toner 6 that has been peeled off is dispersed.

By the way, a moderately rough surface is formed on the surface of the developing sleeve 3, so that the probability of rubbing between the surface of the developing sleeve 3 and the toner 6 is increased, and the transportability of the toner 6 is improved. Has been elevated.

The uneven surface of the developing sleeve 3 has a surface roughness Rz of 1 μm to 10 μm.
The surface is formed by sandblasting with irregular-shaped alundum abrasive grains or sandblasting with regular glass beads. Alternatively, the developing sleeve 3 may be formed by using conductive particles such as metal oxide particles, graphite, and carbon that can form the protrusions independently.
A rough surface is formed on the surface of the convex surface, and the particles forming the rough surface of the convex surface are bound with a binder resin such as phenol resin or fluororesin to form a concave portion on the surface of the binder resin. A rough surface may be formed on the surface of No. 3.

In this embodiment, as the developing sleeve 3,
An aluminum sleeve having a diameter of 16 mm was used as a substrate, and the surface thereof was subjected to a blast treatment with regular glass beads (# 600) to have a surface roughness Rz of about 3 μm.

The elastic blade 4 is pressed against the developing sleeve 3, and the toner 6 that has entered between the two is applied onto the developing sleeve 3 to form a thin layer.

The elastic blade 4 is made of silicon if it is laid down.
Rubber member such as urethane (JIS A has a hardness of 40 °
Is about 90 °), and a part of the surface of the elastic blade 4 facing the developing sleeve 3 abuts in surface contact to press the developing sleeve 3 under pressure.

In the present invention, the contact pressure of the elastic blade 4 against the developing sleeve 3 is preferably 5 g / cm to 200 g / cm in the linear pressure in the generatrix direction of the developing sleeve 3.
In this embodiment, a urethane rubber blade having a hardness of 65 ° and a thickness of 1.2 mm is used as the elastic blade 4, and the blade is brought into contact with the developing sleeve 3 with a linear pressure of 50 g / cm.

The linear pressure is measured by inserting three thin plates of known friction coefficient into the contacting part of the elastic blade 3,
The central thin plate is pulled out with a spring scale, and the linear pressure is converted from the pulling force at that time and the friction coefficient.

The non-magnetic toner 6 is used as a non-magnetic one-component developer, and is made of styrene resin, acrylic resin,
It is formed by dispersing a pigment such as carbon in various thermoplastic resins such as polyethylene resin. In this embodiment, the toner 6 is composed of a copolymer of styrene / acrylic resin and styrene / butadiene resin and a pigment, and has an average particle diameter of 12 μm.
The toner powder of 1. was externally added with 1.0% of colloidal silica.

Next, the elastic roller 5 in this embodiment will be described in detail.

The elastic roller 5 peels off the toner 6 remaining on the developing sleeve 3 and supplies new toner 6 as described above.

As the elastic roller 5, a metal cored bar 51 is used.
On the outer side of the spindle, silicone rubber, EPDM rubber,
A roller foam made of a single-foam foam body, such as CR rubber, whose wall surface does not communicate with the adjacent air bubble part, is used.
The elastic roller 5 is rotationally driven in the direction of arrow c in the figure.

In this embodiment, as shown in FIG. 11, as the elastic roller 5, a metal cored bar 51 having an outer diameter of 5 mm and a silicon rubber foam 52 having a thickness of 5 mm and having an outer diameter of 15 mm was used. I am using. And outer diameter 16
With respect to the developing sleeve 3 of mm, the rotation center A of the elastic roller 5 is movable on a straight line connecting the rotation center B of the elastic roller 5 and the rotation center B of the developing sleeve 3, and the axial distance x between the development sleeve 3 and the elastic roller 5 can be changed. It is configured.

The amount δ (mm) of penetration of the elastic roller 5 into the developing sleeve 3 is the diameter of the developing sleeve 3 α (m
m) and the diameter β (mm) of the elastic roller 5,

[0147]

## EQU2 ## This is expressed by δ = 1/2 (α + β) -x, and in this embodiment, the penetration amount δ (mm) is

[0148]

## EQU00003 ## .delta. = 1/2 (16 + 15) -x = 15.5-x.

The present inventors changed the axial distance x in order to examine the proper range of the penetration amount δ (mm), and conducted an experiment under the following conditions.

That is, the developing device 20 is incorporated in the Canon copying machine FC-2, the surface potential of the electrostatic latent image on the photosensitive drum 1 is set to -600 V in the dark portion and -150 V in the bright portion, and the photosensitive drum 1 and the developing sleeve 3 are set. And the development bias applied between the frequency of 1800Hz, peak-peak voltage 1200V
A DC voltage of -250 V was superposed on the AC voltage of the above, and the gap between the developing sleeve 3 and the photosensitive drum 1 was set to 250 μm. The peripheral speed of the photosensitive drum 1 is 50 m.
The peripheral speed of the developing sleeve 3 is 70 mm / m / sec.
sec, and the peripheral speed of the elastic roller 5 was set to 50 mm / sec.

Under the above conditions, the copying operation of about 2000 sheets was performed while changing the penetration amount δ (mm). The result is shown in Figure 1.
2 shows. In FIG. 12, ◯ means good, Δ means good, and × means bad.

As is apparent from FIG. 12, the elastic roller 5
When the penetration amount δ of the toner is set to 0.2 mm, unevenness occurs in the application of the toner 6 to the developing sleeve 3 by the elastic roller 5 and peeling in the longitudinal direction, which causes uneven density in the image, which is not preferable.

On the contrary, if the penetration amount δ is set to 2.5 mm, the toner 6 is deteriorated and the toner 6 is fused to the developing sleeve 3, causing fog, which is not preferable.

Therefore, the appropriate range of the penetration amount δ of the elastic roller 5 composed of a closed cell foam is 0.3 mm to 2.0 mm.
And more preferably 0.5 mm to 1.5 mm.

Within the above range, unevenness in density due to uneven contact of the elastic roller 5 with the developing sleeve 3 and fogging due to deterioration of the toner 6 due to excessive contact pressure with the developing sleeve 3 do not occur, and the elastic roller 5 is prevented. Can stably supply the toner 6 to the developing sleeve 3 and peel off the undeveloped toner 6 satisfactorily, and an image faithful to the electrostatic latent image on the photosensitive drum 1 can be obtained. .

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. 13 is a sectional view of the developing device according to the second embodiment.

In this embodiment, unlike the first embodiment, the developing sleeve 3 and the photosensitive member 8 are in contact with each other via the toner 6. In order to have such a configuration, in this embodiment, a flexible belt photosensitive member is used as the photosensitive member 8. This Baltic photosensitive member 8 is made of polyethylene terephthalate (trade name: Mylar) or the like having aluminum deposited on the surface layer. For example, an OPC photosensitive layer is formed on the surface of the belt base layer, which is rotationally driven in the direction of arrow d in the figure.

In this embodiment, the peripheral speed of the belt photosensitive member 8 is set to 50 mm / ec, and the developing sleeve 3 is set to a peripheral speed of 100 mm / sec faster than this.
The developing sleeve 3 is provided with a relative speed to the belt photosensitive member 8.
By rubbing the upper toner thin layer against the belt photoreceptor 8, tribo is positively applied to the toner 6 even in this rubbing portion.

The bias applied to the developing sleeve 3 is −
Only the DC component is used, and development is performed by the potential difference from the belt photosensitive member 8.

In this embodiment, the developing sleeve 3 and the belt photosensitive member 8 are in contact with each other.
As compared with the non-contact development of the embodiment, since the force received by the toner 6 in the developing portion is increased, it is expected that the appropriate range of the penetration amount of the elastic roller 5 is narrowed. Therefore, the penetration amount δ is the same as in the first embodiment. (Mm) was changed and about 2000 copy operations were performed. If the penetration amount δ (mm) was small,
Similar to the first embodiment, the penetration amount δ = 0.3 mm or more was good, but when the penetration amount δ (mm) was large, the appropriate range was narrowed.

That is, when the penetration amount δ = 2.0 mm or more,
Unlike the result of the first embodiment, the toner 6 on the developing sleeve 3
Fusing due to fusing of the toner and deterioration of the toner 6 is caused.

As described above, when the belt photosensitive member 8 and the developing sleeve 3 are in contact with each other, it is necessary to keep the special penetration amount δ within an appropriate range. In this embodiment, the proper range of the penetration amount δ (mm) of the elastic roller 5 is 0.3 mm to 1.5 mm from the above result, and the proper range of the first embodiment is actually 0.3 mm to 2.0 mm. It is narrower than.

Within the proper range, even if the belt photosensitive member 8 and the developing sleeve 3 are in contact with each other as in this embodiment, a good image without density unevenness and fog can be obtained.

Although the non-magnetic toner is used in the first and second embodiments, the present invention can be applied to a one-component developing device using a magnetic toner by providing a magnet in the developing sleeve. However, other various modifications are possible within the scope of the invention.

[0165]

As is apparent from the above description, according to the first aspect of the invention, the surface of the developer carrying member is roughened so that a large number of relatively smooth recessed areas are formed, and the surface thereof is roughened. The centerline average surface roughness (Ra) is 0.4 μm to 1.0 μ.
Since it is set within the range of m, the amount of developer and the amount of charge on the developer carrier are properly maintained, and the developer on the developer carrier is surely attached to the image carrier or the developer carrier. Thus, it is possible to obtain an effect that a good image can be stably formed even in a long-term operation.

Further, according to the second invention, since the sliding contact width between the developer carrying member and the elastic roller is set within the range of 2.0 mm to 6.0 mm, the development on the developer carrying member can be performed even during long-term operation. It is possible to obtain an effect that a good and stable image can be formed with low torque without causing fusion of the agent and deterioration of the developer.

Further, according to the third aspect of the invention, since the penetration amount of the elastic roller into the developer carrying member is set within the range of 0.3 mm to 1.5 mm, the developer is not applied to the developer carrying member and is not applied. The developer can be stripped off steadily and satisfactorily, and it is possible to prevent the occurrence of defective images such as image density unevenness and fog when the amount of penetration of the elastic roller into the developer carrier is inappropriate. The effect that a stable image can be stably formed for a long period of time is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a developing device according to a first embodiment of the first invention.

FIG. 2 is a diagram showing a measurement result of a toner conveyance amount with respect to a durable number of sheets.

FIG. 3 is a diagram showing a measurement result of an average amount of tribo with respect to the number of durable sheets.

FIG. 4 is a sectional view of a developing device according to a second embodiment of the first invention.

FIG. 5 is a sectional view of a developing device according to a third embodiment of the first invention.

FIG. 6 is a sectional view of the developing device according to the first embodiment of the second invention.

FIG. 7 is a diagram showing the relationship between roller hardness and sliding contact width.

FIG. 8 is a sectional view of a developing device according to a second embodiment of the second invention.

FIG. 9 is a sectional view of a developing device according to a third embodiment of the second invention.

FIG. 10 is a sectional view of the developing device according to the first embodiment of the third invention.

FIG. 11 is an enlarged cross-sectional view of an elastic roller and a developing sleeve of the developing device according to the first embodiment of the third invention.

FIG. 12 is a diagram showing image quality (density unevenness, fog) with respect to the penetration amount δ of the elastic roller.

FIG. 13 is a sectional view of a developing device according to a second embodiment of the third invention.

FIG. 14 is a cross-sectional view of a conventional developing device.

FIG. 15 is an enlarged cross-sectional view of an elastic roller made of single-cell foam rubber.

[Explanation of symbols]

 1 photosensitive drum (developer carrier, image carrier) 2 developer container 3 developing sleeve (developer carrier) 4 elastic blade (developer regulating member) 5 elastic roller 6 toner (one-component developer) 8 toner stirring Member 20 Developing device

Claims (11)

[Claims] 1. A developer carrying member disposed endlessly movably in an opening of a one-component developer accommodating container having a stirring member is pressed against a restricting member, and the developer is regulated by the restricting member. In a developing device that conveys a one-component developer in the one-component developer accommodating container with the movement of the carrier, a relatively smooth large number of recessed areas are formed on the surface of the developer carrier. A developing device, characterized in that the surface is roughened, and the surface roughness is set in the range of 0.4 μm to 1.0 μm in terms of center line average surface roughness (Ra). 2. The developing device according to claim 1, wherein the one-component developer is non-magnetic. 3. The surface of the developer carrying member is blasted with regular particles.
The developing device described. 4. The surface of the developer carrying member is formed by dispersing conductive powder in a resin to form a relatively smooth concave region with the resin and a raised convex portion with the conductive powder. The developing device according to claim 1, wherein the developing device is a developing device. 5. A developing device comprising a rotatable elastic roller made of a single-foam foam rubber for supplying a one-component developer to a developer carrier, which is in sliding contact with the developer carrier. And the elastic roller have a sliding contact width of 2.0 mm to 6.
A developing device characterized by being set within a range of 0 mm. 6. The developer carrying member is composed of a developing roller rotatably disposed in an opening of a developing container, and the hardness of the elastic roller slidingly contacting the developing roller is 8 ° to 10 °.
The developing device according to claim 5, wherein the developing device is set within a range of (Asker C, 300 g load). 7. An elastic blade for regulating the layer thickness of the developer on the developer carrying member is pressure-contacted on the downstream side in the rotation direction of the developer carrying member with respect to the sliding contact portion between the developer carrying member and the elastic roller. The developing device according to claim 5 or 6, wherein 8. The developer carrying member is a photosensitive drum which is an image carrying member, and the elastic roller that is in sliding contact with the photosensitive drum has a hardness of 8 ° to 1 cell per unit length.
0 ° (Asker C, 300g load), 100 to 300
6. The developing device according to claim 5, wherein the developing device is set within a range of pcs / inch and the surface thereof is polished. 9. The developing device according to claim 5, wherein the one-component developer is non-magnetic. 10. A developing device in which a rotatable elastic roller made of a single-foam foam rubber for supplying a one-component developer to a developer carrier is slidably contacted with the developer carrier, wherein the elastic roller comprises: 0.3mm penetration into developer carrier
A developing device characterized by being set within a range of up to 1.5 mm. 11. The developing device according to claim 10, wherein the one-component developer is non-magnetic.