JP3057142B2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for developing an electrostatic latent image formed on a recording medium, and applies a developing force to a developing roller when a one-component developer is transported to a developing area. The present invention relates to a developing device that transports a developer in a state where the developer is uniformly applied.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic method, such as a copying machine or a laser printer, an electrostatic latent image formed on a photosensitive member as a recording medium is colored in order to visualize the electrostatic latent image. A developing device for attaching a toner composed of a pigment to the electrostatic latent image is provided. Here, a developing device containing toner of each color to colorize the electrostatic latent image as well as black is exchangeably provided in the image forming apparatus main body.

In particular, in order to color a toner as a developer, a two-component system has hitherto been mainly used. That is,
When a toner is made of a color pigment and a resin, a desired color cannot be created if a magnetic member and other members are mixed.

[0004] Therefore, in order to obtain a one-component color toner, the one-component toner is not a magnetic toner but a non-magnetic toner. When such a non-magnetic toner is used, the magnetic brush developing method cannot be used unlike a conventional developing device. That is, the toner is attracted to the peripheral surface of the developing roller by the magnetic force and cannot be applied to a fixed amount of the developer by the regulating member.

For this reason, Japanese Patent Application Laid-Open No. 2-101485 proposes, for example, a developing device as shown in FIG. The developing device 100 shown in FIG. 1 includes a developing roller 101 that conveys a predetermined amount of developer to a photoconductor on which an electrostatic latent image is formed and visualizes the electrostatic latent image.
A toner 103 which is a one-component developer is stored in a developing tank 102 rotatably supporting the toner 1.
Is supplied to the developing roller 101 and a toner supply roller 104 is rotatably provided to adhere the toner to the developing roller 101. further,
A regulating member 105 is pressed against the peripheral surface of the developing roller 101 in order to equalize the amount of toner attached to the developing roller 101 to a constant amount. Thereby, the concave portion 1 of the supply roller 104
When the toner is supplied at 06, the toner 103 is pressed against the developing roller 101 when passing between the developing roller 101, adheres to the developing roller 101, and is conveyed according to the rotation of the developing roller 101. On the way, the toner passes through the regulating member 105 and is transported to a developing area opposed to the photoconductor in a uniform amount.

[0006]

However, in the conventional developing device 100 shown in FIG. 5, the toner 103, which is a developer, is uniformly transported to the developing position when passing through the regulating member 105. It is very difficult to do. In other words, it is necessary to uniformly press the regulating member 105 over the entire length of the developing roller 101 in the axial direction, but it is very troublesome to adjust the pressure for uniform pressing, and it is very difficult to achieve a uniform pressing state. And the distribution of the pressing force in the axial direction becomes inconsistent, so that the amount of applied toner (the amount of application)
Irregularities occur. Further, it is very difficult to make the contact portion of the regulating member 105 with the developing roller 101 a smooth and uniform plane. Therefore, if irregularities are formed in a portion that is in pressure contact with the developing roller 101, a problem remains in uniform application.
In this case, if the regulating member 105 is too smooth,
The rotation torque of the developing roller 101 also increases.

Further, even if the toner can be uniformly applied by the regulating member 105, the development is repeated, so that when a halftone image or a solid black image is developed, a portion along the paper transport direction is partially used. And the line width tends to gradually decrease. This tendency becomes remarkable when the remaining amount of the toner in the developing tank decreases. If this is further advanced, the torque of the developing device, particularly the torque for rotating the developing roller 101, increases, and the rotation of the developing roller becomes impossible, that is, there is a problem that the lock is released.

[0010] This is because the toner regulated by the toner regulating member 105 is changed to the regulating member 05 as the development is repeated.
The regulating member 10 is gradually increased by the pressure between
This is for fusing to No. 5. As a result, the fused portion becomes a convex surface, and the pressing surface of the regulating member 105 with the developing roller 101 becomes uneven.
The amount of toner applied to the surface becomes uneven in the circumferential direction along the uneven surface, and is not constant along the axial direction, but forms a line streak in the paper transport direction as described above.
In addition, the rotational torque of the developing roller 101 increases due to the fused toner.

On the other hand, according to the conventional developing device shown in FIG. 5, when toner is supplied by the supply roller 105 and adheres to the development roller 101, the toner passes between the development roller 101 and the toner supply chamber 107. As a result, the action of adhering the toner to the developing roller 101 is increased by increasing the toner powder pressure. However, if the toner powder pressure in the supply chamber 107 is not constant due to the relationship between the supply roller 105 and the developing roller 101 at this time, the charge amount due to friction of the toner 103 will not be stable, and the toner will be transferred to the developing roller 101 side. The developing roller 1
01 is not stable.

[0010] According to the developing device 100 shown in FIG. 5, the position of the member 108 for scraping the toner remaining in the concave portion 106 of the supply roller 105 for supplying the toner varies according to the rotation of the supply roller 105. Therefore, the upper toner supply chamber 10
7, the powder pressure of the toner at that position is not constant, as described above. Therefore, there remains a problem that not only the frictional charging of the toner is not stable but also greatly affects the amount of toner applied to the developing roller 101.

In the above, the amount of non-magnetic one-component toner adhering to the developing roller 101 has been described. However, even with magnetic one-component toner, it is necessary to keep the amount of toner adhering to the developing roller 101 constant. For this purpose, a regulating member 105 is similarly provided in the developing tank. The regulating member 105 also comes into pressure contact with the developing roller 101 to regulate the amount of toner adhered thereto. Therefore, the toner adheres to the regulating member 105, and if this is repeated, the toner adheres. Occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a uniform application amount of a one-component toner to a developing roller, thereby enabling stable development. In particular, according to the invention of the present application, it is an object of the present invention to minimize the adhesion of toner to a regulating member that regulates the amount of toner applied to a developing roller and to finally fuse the toner, thereby enabling uniform application. I do.

[0013]

A developing device according to the present invention is provided so as to face a recording medium, and a toner supply member is provided in a developing tank in order to attach toner to a developing roller for conveying and developing the developer. After the supplied toner adheres to the developing roller, a regulating member that regulates the amount of application at that time is formed by a rotating cylindrical regulating roller.

More specifically, the developing device of the present invention is provided so as to face a photosensitive member which is a recording medium, and transports toner to a developing area opposed to the photosensitive member to perform development. A supply member that supplies toner to the developing roller , the supplied toner has a constant pressure at a position facing the developing roller.
A coating member for forming a holding chamber such as
Toner adhered to the developing roller, and the toner
A rotating roller-shaped regulating roller that regulates the
Only be configured, the regulating roller is rotating driven in the same direction at a position in contact with the rotation direction and the developing roller of the developing roller.

The peripheral speed at which the regulating roller rotates is set higher than the peripheral speed of the developing roller.

The regulating roller is formed of a conductive member and is connected to a ground potential.

Further, in order to remove the toner adhered to the regulating roller and to prevent the adhered toner from fusing,
A cleaning member is provided in contact with the surface of the regulating roller after regulating the amount of application to the developing roller.

[0018]

According to the developing device of the present invention, the toner in the developing tank constituting the developing device is supplied to the staying chamber , which is a coating area facing the developing roller, as the supply member rotates. The supplied toner is kept under a constant pressure in a stagnant chamber.
At the same time as frictional charging with the rotating developing roller, the developing roller
Roller, which is effectively applied and applied to the regulating roller.

At this time, the amount of toner adhered to the developing roller is regulated in accordance with the rotation of the regulating roller, and after passing through the regulating roller, the toner is exposed in a state where a certain amount of the toner is regulated and applied to the developing roller. The recording medium is conveyed to a developing position facing a recording medium as a body. Here, since the developing roller and the regulating roller are rotated in the same direction at the contact portion, the friction between the toner adhering to the developing roller surface and the regulating roller is reduced, and the developing roller and the regulating roller are in contact with the toner. No wasteful energy such as heat generation is consumed, and toner can be regulated efficiently. In particular, since the regulating member has a roll (cylindrical) shape, even if some irregularities occur partially, the amount of applied toner can be made uniform by rotation. In addition, since the entire regulating roller is brought into pressure contact with the developing roller, it is easy to make the pressure contact state of the pressure contact portion uniform.

In particular, even if some irregularities are formed on the roller surface, the portion in contact with the developing roller constantly changes, so that the surface of the new regulating roller comes into contact with the developing roller during the rotation process and adheres to the roller. It acts to smooth out any uneven state. In this case, even if the toner adheres to the regulating roller,
Even if irregularities due to the toner adhesion portion are formed by the rotation of the regulating roller, the non-uniform application is leveled because the new regulating surface comes into contact with the developing roller. Therefore, it is important that the rotation of the regulating roller be faster than the rotation of the developing roller and that the position in contact with the developing roller be constantly changed.

Further, by connecting the regulating roller to the ground potential, it is possible to prevent the charged toner from electrostatically adhering to the regulating roller. For this reason, the adhered toner is fused to the regulating roller, and as a result, a factor such as forming an uneven surface on the regulating roller surface is eliminated. This makes it possible to make the amount of toner applied to the developing roller constant.

Further, by providing a means for cleaning the toner adhering to the regulating roller after the regulation of the amount of application to the developing roller is completed, it is possible to prevent the toner from adhering to the regulating roller surface due to the adhesion of the toner. Can be eliminated.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an example of a developing device used in an image forming apparatus using electrophotography according to the present embodiment. FIG. 2 is a front view showing a state in which a developing roller constituting the developing device and a regulating member for regulating the amount of toner adhering to the developing roller are pressed against each other. FIG. 3 is a diagram showing the developing device of the present invention in an image forming apparatus. FIG. 2 is a schematic view of an image forming portion applied to a certain laser printer.

The developing device of the present invention can be applied not only to the laser printer shown in FIG. 3 but also to a developing device of an image forming device that visualizes (visualizes) a formed latent image with toner. Can be used as

In FIG. 3, reference numeral 1 denotes a cylindrical shape (drum)
A photosensitive member which is a recording medium formed on the photosensitive member;
Is rotated at a constant speed in the direction of the arrow during image formation. Various devices for forming an image are arranged around the photoconductor 1.

In the figure, reference numeral 2 denotes a charger for uniformly charging the surface of the photoconductor 1, 3 denotes a laser beam irradiation device for irradiating the charged photoconductor 1 surface with an optical image, and 4 denotes the photoconductor 1 of the present invention. A developing device 5 for visualizing the electrostatic latent image formed on the surface; a transfer roller 5 for transferring the developed image, that is, a toner image to a sheet in a properly conveyed sheet state;
Reference numeral 6 denotes a cleaning device for removing toner remaining after the transfer from the surface of the photoconductor 1 and preparing for the next image formation.

The laser beam irradiation device 3 converts image information input from the outside into optical information based on a control signal from a microcomputer 7 for controlling the entire laser printer, and converts an optical image to the surface of the photosensitive member 1. The semiconductor laser is driven under the control of the control circuit 8. As a result, an electrostatic latent image is formed on the surface of the photoconductor 1 by charges corresponding to the irradiated optical image. The toner adheres to the electrostatic latent image in the next developing device 4 and is developed. In this case, the polarity of the charging is set so that the toner adheres to the region irradiated with the light.

The image formed as described above, that is, the toner image, is electrostatically transferred to an appropriately conveyed sheet by supplying a voltage to a transfer roller, and the sheet is separated from the photoreceptor 1 and fixed (not shown). After passing through the apparatus, it is carried out of the image forming apparatus.

The developing device 4 used in the image forming apparatus having the above-described structure is, for example, a one-component type, as shown in FIG. 1, which conveys non-magnetic toner to a developing area facing the photoreceptor 1. is there. The developing device 4 includes a toner 4 as a developer.
In a developing tank 41 for storing the toner 0, a stirring member 42 for stirring and conveying the toner 40 stored therein, a supply member 43 for supplying the toner conveyed by the stirring member 42 to the developing roller, and the photosensitive member 1 are opposed to each other. A developing roller 44 for conveying the toner supplied to the developing area and a regulating roller 45 for regulating the amount of toner applied to the developing roller 44 are provided rotatably.

The rotating shaft of the stirring member 42, the supply member 43, the developing roller 44 and the regulating roller 45 is
2 is rotatably supported on the side wall surface constituting
As shown in FIG. 5, a driving gear 44b fixed to one end of a rotating shaft 44a of a developing roller 44 protruding outside the developing tank 4 includes:
Rotational force from a motor as a drive source is transmitted as necessary via transmission means such as a clutch. A driven gear 45b meshing with the drive gear 44b is fixed to a rotation shaft 45a of the regulating roller 45.
It is rotated in the direction opposite to the rotation direction of. Therefore, in the region of the contact portion between the developing roller 44 and the regulating roller 45, the peripheral surface is rotationally driven so as to move in the same direction.

Further, since the stirring member 42 and the supply member 43 are rotated in the directions shown in the figure, they are transmitted via a driven gear (not shown) which meshes with a driving gear 44b of the developing roller 44.

Further, in the developing tank 41, an application member 46 is provided to form a partition for partitioning a part of the tank in order to form a circulation path of the toner 40. The stirring member 42 is separated. The coating member 46 is arranged at a predetermined distance d from the developing roller 44, and a scraping member 47 made of a polyethylene terephthalate (PET) film is fixed to the tip of the coating member 46. The distal end area of the scraping member 47 reaches the peripheral surface of the supply member 43, and at the distal end, the toner attached to the supply member 43 is scraped off, and the toner 40 supplied from the stirring member 42 like the application member 46; Stirring member 4
The toner 40 stored in the area 2 is divided.

As shown in FIG. 2, the regulating roller 45 is in pressure contact with the developing roller 44 with a constant load, and the amount of toner adhering to the developing roller 44 by this pressure contact is adjusted to a constant application amount. regulate. This regulating roller 45
In the room formed by the developing roller 44 and the applying member 46, the toner supplied by the supplying member 43
And a stagnant chamber 48 for temporarily storing toner conveyed through a narrow area facing the developing roller 44. Further, in order to prevent the sequentially supplied toner from applying a load of a certain pressure or more, the toner is returned to the toner storage area of the stirring member 42 of the developing tank 41 in correspondence with the staying chamber 48. Are formed in the application member 45. As described above, the toner 40 that has been stirred by the stirring member 42 passes through the supply member 43, the distance d between the developing roller 44 and the coating member 46, and the circulation path that passes through the retention chamber 48. Then, the developing roller 4 is
4 is circulated and conveyed to the stirring member 42.

As shown in FIG. 2, the regulating roller 45 urges both ends of the rotating shaft 45a toward the developing roller 44 by a spring 50 so as to press the developing roller 44 with a constant pressure load. ing. One end of the spring 50 is fixed to a mounting member 51 fixed to the developing tank 41, and the other end is in contact with the rotation shaft 45 a of the regulating roller 45, and presses the regulating roller 45 against the developing roller 44.

In the developing device 4 having the above structure, the toner agitated and conveyed by the agitating member 42 is supplied to the supplying member 43.
Is supplied to the developing roller 44 through a passage at the bottom of the developing tank 41. Toner 40 supplied by supply member 43
Is fed into a narrow region (interval d) between the developing roller 44 and the coating member 46. Before this, the toner 40 attached to the supply member 43 is scraped off by the scraping member 47.
Then, the toner 40 is pressed and applied to the developing roller 44 when passing through the interval d of the narrow region. Also,
At this time, when the toner 40 is compressed, the toner 40 is applied in close contact with the developing roller 44, and at the same time, frictional charging occurs.

The toner 40 that has passed through the interval d in the narrow region between the developing roller 44 and the coating member 46 is temporarily stored in the staying chamber 47, and if the pressure becomes higher than a predetermined pressure by the sequentially supplied toner, the coating member 46 Is returned to the toner storage area where the agitating member 42 is disposed through the opening 49 provided in the toner container. The toner 40 in the stagnation chamber 47 is compressed by the supplied toner and charged by friction caused by rotation with the developing roller 44. In this case, the stagnant chamber 47 has a constant volume, and when the amount of supplied toner increases and becomes equal to or higher than a certain pressure, the toner is supplied to the agitating member 4 through the opening 49.
Since it is returned to the two sides, a stable and constant pressure is applied. This stabilizes the amount of the toner 40 applied to the developing roller 44, and also stabilizes the triboelectric charging.

On the other hand, the amount of the toner 40 applied and adhered to the developing roller 44 is regulated by a rotating regulating roller 45. In this case, since it is pressurized to a constant pressure at the residence chamber 4 8, the toner of a predetermined thickness is applied to the developing roller 44. The rotation of the regulating roller 45 further regulates the toner layer to a constant thickness, and
Is transported to the developing area opposite to.

At this time, since the regulating roller 45 rotates in the same direction as the direction in which the toner is conveyed, that is, the direction in which the developing roller 44 rotates, the friction between the regulating roller 45 and the toner is reduced. Useless energy consumption such as heat generation in a portion is small, and the amount of toner applied to the developing roller 44 can be efficiently and uniformly regulated. Then, the toner 40 is regulated by the regulating roller 45 due to the unnecessary heat generation.
No fusing occurs.

That is, the toner regulating roller 4
5 is prevented from being fused, and no irregularities are formed on the surface of the regulating roller 45 due to the fusion of the toner, so that a factor that hinders the uniform application of the toner can be eliminated. Even if the toner as the developer adheres to the regulating roller 45, the regulating roller 45 does not always contact the applied toner on the developing roller 44 at a fixed place, and its surface constantly changes by rotating. Therefore, the coating is not uniform over the entire length of the peripheral surface of the developing roller 44, but is not uniform over the entire length of the peripheral surface of the developing roller 44.

This is because the regulating roller 45 is
And the area to be regulated is substantially widened, so that the toner layer after application can be further regulated.
4 can be thinner and more uniform.

Here, if the rotation speed of the regulating roller 45, particularly the speed (peripheral speed) of the peripheral surface of the regulating roller 45, is made faster than the speed (peripheral speed) of the peripheral surface of the developing roller 44, the developing roller 44 is regulated. The position of the regulating roller 45 gradually shifts, and the new position regulates the part that has been regulated earlier. Therefore, even if coating failure occurs due to the partial uneven surface of the regulating roller 45, regulation by the new regulating surface is performed. Thereby, the previously applied portion is leveled and uniform application becomes possible. That is, if the peripheral speed of rotation is the same for the regulating roller 45 and the developing roller 44, the position where the regulating roller 45 regulates is the same until the position is separated from the developing roller 44. However, if the peripheral speed of the regulating roller 45 is high, Since the regulated position changes in the rotational direction until the regulated position is separated from the developing roller 44, the area (region) for regulating the amount of application of the developing roller 44 becomes wider, and even if the applied amount is partially nonuniform, the regulating roller By the rotation of 45, the non-uniform part is leveled and the whole surface can be uniformly coated.

Even if the peripheral speed of the regulating roller 45 is made slower than the peripheral speed of the developing roller 44, the toner 40 adhered to the developing roller 44 is regulated by the regulating roller 45 and the portion gradually changes. Can be obtained, but the surface regulated by the regulation roller 45 (region in the circumferential direction of rotation)
Is larger when the peripheral speed of the regulating roller 45 is increased.

Here, the regulating roller 45 is connected to the developing roller 44.
In order to increase the speed, for example, as shown in FIG. 2, a driven gear 45b fixed to a rotation shaft 45a of the regulating roller 45
By appropriately setting the gear ratio of the driving gear 44b fixed to the rotating shaft 44a of the developing roller 44, the speed ratio between the two can be easily adjusted. That is, in order to increase the peripheral speed of the regulating roller 45, the rotational speed can be increased by making the number of teeth of the driven gear 45b smaller than that of the driving gear 44a. Speed can be adjusted freely.

When the developing roller 44 and the regulating roller 45 are driven to rotate by separate driving sources, that is, individually provided driving motors without setting the speed ratio by the driving member, the rotation speed of the driving mote is reduced. By controlling, the peripheral speed of the developing roller 44 and the regulating roller 45 can be easily set freely.

The developing roller 44 is made of a material such as rubber which is elastically deformed so that the toner is applied well and the photosensitive member 1 is brought into contact with a desired nip. For example, as a material of the developing roller 44, a conductive elastic member such as urethane rubber, silicon rubber, NBR rubber, or the like is used. The hardness of the rubber used for the developing roller 44 is 50 to 50 for Asker C.
If the angle is 90 degrees, the nip with the photoreceptor 1 cannot be taken if it is hard, and the applied amount of toner will not be constant if it is too soft.
The above materials are effective when the toner to be used is a non-magnetic one-component system.

However, if the toner is a magnetic one-component toner, the developing roller needs to adsorb the toner by magnetic force. And a magnet having a plurality of magnetic poles. As a result, as described above, the toner can be adhered to the rotating sleeve by magnetic force without providing the application member 46 and the like, and at the same time, the adhered toner is regulated by the rotation regulating roller 45 so that the applied amount becomes constant. Can be controlled.

Hereinafter, a case where a non-magnetic one-component toner is used will be described. The resistance value of the developing roller 44 is preferably 10 ⁴ to 10 ⁸ Ωcm, and 10 ⁶ to 10 ⁸ Ωcm.
The one of 10 ⁷ Ωcm is optimal. If the resistance value is low, the charge of the charged toner is discharged, and a resistance that does not cause this discharge is suitable. If the resistance value is too high to apply the developing bias to the roller, the toner may adhere to a non-image area of the charged toner, that is, an area where the toner should not adhere. Here, if the resistance value of the developing roller 44 is non-uniform, shading corresponding to the variation in the resistance value occurs in the image. Therefore, it is effective to use a material having a uniform resistance value by dispersing a conductive material in rubber. In particular, a material having good dispersibility is selected as the conductive material to be dispersed.

The material of the regulating roller 45 for regulating the amount of application to the developing roller 44 is preferably a material having good abrasion resistance, such as ceramic, glass or resin.

The supply member 43 for supplying the toner 40 to the developing roller 44 is a regular polygonal roller.
In this case, the surface on which the toner is supplied becomes constant, and the supply amount can be stabilized. However, when the polygon has a large number of corners, the carrying capacity decreases, and when the number is small, the carrying capacity increases. However, if the amount is too small, the unevenness of the transport amount is not good for commercial business. For this reason, it is preferable that the shape be a quadrangle or more, and preferably 5 or more and up to an octagon.

As the load for pressing the regulating roller 45 against the developing roller 44, if the load is small, the regulating ability is reduced, and the toner may blow out at the regulated position. Conversely, if the load is large, the toner is
It becomes easy to be fused to the side. Therefore, the load on the developing roller 44 of the regulating roller 45 is optimally 500 to 2000 fg, preferably about 700 to 1200 gf.

Next, the advantages of the present invention will be described with reference to several embodiments of the present invention.

(Embodiment 1) The developing roller 44 has a diameter of 1
6mm, the material is urethane rubber, and its resistance value is 10 ⁷
Ωcm and hardness Asker C of 70 degrees were used. The developing roller 44 is arranged so as to have a fixed nip (length / width in the circumferential direction in contact with the photoconductor) of 0.3 mm with the photoconductor 1. At this time, the peripheral speed of the rotating roller 44 of the developing roller 44 is set to 32.5 mm / sec.

The regulating roller 45, which is in pressure contact with the developing roller 44, has a diameter of 10 mm, is made of ceramic, and is pressed against the developing roller 44 with a load of 800 gf.
The peripheral speed of rotation was set to 35 mm / sec. As shown in FIG. 2, the peripheral speed of this rotation was adjusted by appropriately setting the ratio of the number of gears between the drive gear 44b and the driven gear 45a.

For comparison with the developing device according to the present invention, as a comparative example, the regulating roller 45 is made of a fixed prismatic aluminum regulating member which does not rotate and is made of 1K.
The developing roller 4 having the same structure as that of the present embodiment with a load of gf
Pressurized to 4.

In particular, both of the present invention and the comparative example have the structure as shown in FIG. 1 as the developing tank 41, and the supply member 43 has a heptagonal shape with a diameter of 15 mm and a speed of 40 mm / sec. I made it.

Table 1 below shows the results of the comparative example, and Table 2 shows the results of the present invention. The toner used is a non-magnetic one-component toner.

[0058]

[Table 1]

[0059]

[Table 2]

As described above, the regulating roller 4 according to the present invention
It can be understood that the amount of application to the developing roller 44 by 5 is always stable, and the replacement time of 20K (1K = 1000 sheets) of the regulation roller 45 is 4 times larger than the conventional replacement time of 5K for the regulation member. It is about twice as long. Therefore, the service life can be extended.

In the case of a conventional prismatic regulating member, when the number of printed sheets is about 5K, streaks are formed when a halftone image is formed, so that the amount of applied toner is uniform in the circumferential direction. However, according to the regulating roller 45 of the present invention, no streak is formed until the temperature reaches about 20K, so that it is clear that uniform application is always performed.

Here, since the developing roller is always in pressure contact with the regulating roller 45 for regulating the layer thickness of the toner with a constant load, it is important that the developing roller be a rubber material having a small permanent distortion. Since the member is the regulating roller 45, the problem of distortion can be solved as compared with the prismatic regulating member.

(Embodiment 2) The developing roller 44 has a diameter of 2
0 mm, the material is silicon rubber, and its resistance value is 10 ⁶
Ωcm and hardness Asker C of 60 degrees were used. The developing roller 44 is arranged such that a constant nip width with the photoconductor 1 becomes 0.15 mm. At this time, the peripheral speed of the rotating roller 44 of the developing roller 44 is set to 25 mm /
Set to sec.

The regulating roller 45, which is in pressure contact with the developing roller 44, has a diameter of 10 mm, is made of iron, and is brought into pressure contact with the developing roller 44 with a load of 800 gf to set the peripheral speed of rotation to 35 mm.

Further, as shown in FIG.
A cleaning member 52 made of urethane sponge is provided which is pressed against the regulating roller 45 after the amount of toner applied to the surface of the regulating roller 45 is fixed, and removes toner adhered to the surface of the regulating roller 45. The load for pressing the cleaning member 52 against the regulating roller 45 was set from 50 gf to 200 gf. The supply member 43 for supplying the toner used was the same as that in the first embodiment.

With the above configuration, the same effect as in the first embodiment can be obtained, and at the same time, the toner adhering to the regulating roller 45 can be removed by the cleaning member 51. The application amount will not be unstable. The results are shown in Table 3 below.
Shown in

[0067]

[Table 3]

As shown in Table 3 above, the amount of toner adhering to the regulating roller 45 can be reduced.
Can always be kept constant. Also,
The effect of further extending the life of the regulating roller can be obtained.

(Embodiment 3) Next, an embodiment in which a one-component magnetic toner is used instead of a one-component non-magnetic toner will be described.

Here, by utilizing the magnetic toner, the developing roller 44 is provided inside a cylindrical rotary sleeve made of aluminum having a diameter of 20 mm and having a magnetic force of 600G.
It is constituted by providing a magnet consisting of poles. This developing roller 44
Of the photoconductor, for example, the selenium photoconductor 1, was kept at 200 μm. At this time, the peripheral speed of the rotating sleeve was set to 50 mm / sec.

The regulating roller 45, which is in pressure contact with the developing roller 44, particularly the rotating sleeve, presses aluminum having a diameter of 10 mm against the developing roller 44 with the same load as in the first embodiment, and the rotating peripheral speed at this time is reduced. It was set to 50 mm / sec.

Further, the toner in the developing tank is
The supply roller 43 that feeds the toner to the roller 4 is formed in a heptagon with a diameter of 15 mm and the peripheral speed at that time is set to 40 mm / sec to supply the toner.

In the case of the above-described one-component magnetic toner, the amount of the toner applied to the surface of the rotary sleeve constituting the developing roller 44 was also uniformly applied at all times, and stable development was achieved.

Further, since the regulating roller 45 is made of aluminum, if the regulating roller 45 is grounded, the charged toner does not adhere to the regulating roller 45 electrostatically. The amount to wear was also reduced.

Here, a developing bias is applied between the developing roller 44 and the photosensitive member 1. However, since the regulating roller 45 is in contact with the developing roller 44 via the toner, there is a problem that a leak occurs. It could not be confirmed in the experiment. Therefore, the regulation roller 45 can be grounded via a high-resistance element to completely eliminate the problem of leakage.

The material of the regulation roller 45 may be a metal material such as iron or stainless steel instead of aluminum, and may be grounded, or may be made of a resin containing carbon or the like as a conductive substance. Since the iron is a ferromagnetic material, the magnetic toner may be magnetically adsorbed.
Not very suitable. However, if the toner is a one-component non-magnetic toner, the regulating roller 45 may be made of iron.

Although the rotation peripheral speeds of the regulating roller 45 and the rotary sleeve as the developing roller 44 are set to be the same, the rotational speed of the regulating roller 45 is set to be higher or lower than that of the developing roller. By doing so, the effect of regulating the amount of toner attached, that is, the effect of uniform application increases.

Example 4 The photosensitive layer was made of urethane conductive rubber having a diameter of 20 mm, and the photosensitive layer was an organic photoconductive layer (OPC).
Is provided with a developing roller 44 arranged with a constant nip of 0.2 mm. At this time, the rotation peripheral speed of the developing roller 44 is set to 70 mm / sec.

A regulating roller 45 having a diameter of 10 mm and made of aluminum was pressed against the developing roller 44 with a load of 800 gf, and the peripheral speed of the rotation was set to 50 mm / sec.

Further, the toner in the developing tank is
The feeding member 43 for feeding and mixing into the sample No. 4 was formed in a heptagon having a diameter of 15 mm, and the rotating peripheral speed was set to 40 mm / sec.

Then, as shown in FIG. 3, for example, as shown in FIG. 3, the regulating roller 45 having the above-described configuration is supplied with the same polarity as that of the negatively charged non-magnetic one-component toner 40 by the power supply means 9. For example, a voltage of -500 V was applied.

As a result, the charged toner 40 is not electrostatically attracted to the regulating roller 45, and the toner is not fused to the regulating roller 45. In this case, after the photoconductor is negatively charged, the image portion such as a character or a figure is irradiated with the laser, and the latent image in which the electric charge in the irradiation region of the laser light is discharged is formed. As shown in FIG. 3, a bias voltage of, for example, -300 V was applied to the developing roller 44 via the power supply unit 10 so that the charged toner was electrostatically attracted to the portion irradiated with the laser beam.

Further, the charged toner 40 is
Also, no discharge is caused via the terminal 5.

(Embodiment 5) Next, an embodiment showing the relationship with the rotation speed of the regulating roller 45 when toner is applied to the developing roller 44 will be described below. The toner used was a non-magnetic one-component toner.

The developing roller 44 has a diameter of 2 mm.
The developing roller 44 is made of urethane conductive rubber having a thickness of 0 mm, and the developing roller 44 is disposed so that the nip of the developing roller 44 is 0.2 mm on the photosensitive member 1 having an organic photoconductive layer (OPC).
At this time, the peripheral speed of the rotating roller 44 of the developing roller 44 is set to 45 mm / sec.

The regulating roller 45, which is pressed against the developing roller 44, is made of cylindrical aluminum having a diameter of 10 mm, and is pressed against the developing roller 44 with a load of 800 gf. Experiments were performed on the application state of the developing roller 44 and the amount of toner adhering to the regulating roller 45 when the rotating speed of the regulating roller 45 was variously changed.

Further, the supply member 43 has a square shape with a diameter of 10 mm and a peripheral speed of 25 mm / sec.
The toner was supplied to the developing roller 44.

As a result of the experiment, when the peripheral speed of rotation of the rotating regulating roller 45 is lower than the peripheral speed of the developing roller 44, although the amount of applied toner is stable, the degree of adhesion of the toner to the regulating roller increases. However, when the peripheral speed of the regulating roller 45 becomes faster than the peripheral speed of the developing roller 44, the amount of applied toner becomes stable and the amount of toner adhering to the regulating roller 44 decreases. This is because, when the rotation speed of the regulating roller is reduced, the developing roller 44 rotates to apply the toner to the regulating roller 45 side, and the toner adheres to the regulating roller side. Since the toner acts to regulate the toner adhered to the toner, the amount of toner adhered is reduced.

Further, if the peripheral speed of the regulating roller 45 is increased, the toner adhered to the developing roller 44 is scattered, which not only causes a problem in terms of uniform application, but also scatters the toner out of the developing tank, and the image forming apparatus The inside will be soiled with toner.

Therefore, the peripheral speed at which the regulating roller 45 rotates is 1.01 to the peripheral speed of the developing roller 44.
It is preferably set to a range of from 2.0 to 2.0, and most preferably from 1.05 to 1.5.

The supplied toner passes between the coating member 46 and the developing roller 44 and is temporarily stored in the staying chamber 48. When a predetermined pressure or more is generated, the stored portion of the stirring member 42 is opened through the opening 49. Sent back to.

As described in each of the above embodiments, in order to use a one-component toner and apply a fixed amount of the toner to the developing roller 44 which conveys the toner to the developing position facing the photosensitive member 1, It is important to provide a rotating regulating roller 45 which is a regulating member.

Further, with this rotating regulating roller 45,
In order to make the amount of toner adhering to the developing roller 44 uniform, the rotation direction of the regulating roller 45 is set to be the same as the rotation direction of the developing roller 44 in the contact area.

Further, in order to increase the uniformity in applying the toner, it is important that the peripheral speed at which the regulating roller 45 rotates is made slower or faster than the peripheral speed of the developing roller 44. In addition, if toner adheres to the regulating roller 45, the amount of toner applied to the developing roller 44 is not uniform. For this reason, it is important that the rotational peripheral speed of the regulating roller 45 be higher than the rotational peripheral speed of the developing roller 44. Become.
In this case, a cleaning means for removing toner adhering to the regulating roller 45 is provided to the regulating roller 45 and the developing roller 44.
It is also an effective method to provide pressure contact after regulating toner application.

In order to stabilize the amount of application to the developing roller 44, it is effective to provide a means for pressing the supplied toner against the developing roller 44. Therefore, it is effective that a constant pressure is always applied in a path where the supplied toner reaches the developing roller 44. As shown in FIG. 1, the passing area between the developing roller 44 and the coating member 46 is fixed. One way is to keep the distance, and before the amount of toner applied to the regulating roller 45 is regulated, when the toner adheres to the developing roller 44, the force for pressing the toner may be kept constant. It is an effective method. Therefore, the stagnation chamber 4 partitioned by the coating member 46, the regulating roller 45, and the developing roller 44.
It is effective to provide a circulation path so that the toner is returned to the position of the stirring member 42 in the developing tank 41 when a certain pressure is applied.

[0096]

According to the developing device of the present invention, the rotation of the developing device is restricted while being conveyed to the developing area facing the recording medium.
Before being regulated by the roller,
A certain thickness is applied to the image roller,
Thus, the toner can be uniformly applied to the developing roller.
At this time, the toner is prevented from adhering to the regulating roller, the applied amount is not changed by the adhered toner, the toner uniformly applied to the developing roller is always transported to the developing area, and stable developing is performed. Can be made possible.

Further, by making the peripheral speed of the regulating roller higher than that of the developing roller, the amount of application of the toner to the regulating roller can be reduced while the application amount is stabilized, and the life of the regulating roller can be extended. . In this case, the influence of toner adherence can be prevented as much as possible by providing the grounding of the regulating roller or a cleaning means, and the effect of constantly applying toner can be promoted, and the life of the regulating roller can be extended.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a specific example of a developing device according to the present invention.

FIG. 2 is a front view illustrating an example of a configuration in which a regulating roller that regulates an amount of applied toner constituting the developing device according to the present invention is pressed against the developing roller.

FIG. 3 is a cross-sectional view of the entire apparatus in which the developing device of the present invention is applied to a laser beam printer of an image forming apparatus.

FIG. 4 is a sectional view showing another example of the developing device of the present invention.

FIG. 5 is a sectional view showing a conventional developing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 4 developing device 40 one-component non-magnetic toner 41 developing tank 42 stirring member 43 supply member 44 developing roller 45 regulating roller 46 coating member 47 scraping member 48 spring 49 opening

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yuhi Yui 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References JP-A-63-259580 (JP, A) JP-A-5 -35072 (JP, A) JP-A-2-232674 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/08

Claims (6)

(57) [Claims] In a developing tank storing a one-component toner,
Developing roller that transports toner to the area facing the recording medium
A supply member for supplying toner to the developing roller;
Regulates the amount of toner attached to the developing roller
Regulating roller pressed against the developing roller
The toner supplied by the supply member has a constant pressure.
Forming a stay chamber including the developing roller and the regulating roller.
And a coating member for controlling the control roller in a region where the control roller contacts the developing roller.
Rotate the drive so that it is in the same direction as the image
A developing device characterized in that the developing device is moved . 2. The developing device according to claim 1, wherein a peripheral speed at which said regulating roller rotates is set faster than a peripheral speed at which said developing roller rotates. 3. The regulating roller is formed of a conductive member.
3. The developing device according to claim 1, wherein said regulating roller is grounded. Wherein the member for cleaning the developing roller of said regulating roller surface after regulating the application amount of the toner,
2. The developing device according to claim 1, wherein said developing device is disposed in pressure contact with said regulating roller. 5. The pressure of the staying chamber is maintained at a constant pressure in the coating member.
Opening to return toner to toner storage area
The developing device according to claim 1, wherein: 6. The developing roller according to claim 1, wherein the rotational peripheral speed of said regulating roller is controlled by a developing roller.
The rotation peripheral speed of the rotor was set to 1.01 to 2.0.
3. The developing device according to claim 2, wherein: