JPH04249275A - One-component developing device and its production - Google Patents

Abstract

PURPOSE:To reduce a change in the quantity of a developer sticking to the surface of a developer carrier when it is used for a long period and to prevent the change in a developing density in the lapse of time, in a one-component developing device which turns the developer into a thin layer on the developer carrier and sticks the developer to an electrostatic latent image to make it, visualizable. CONSTITUTION:The surface of the developer carrier 6 is roughly grounded with a grinding material having high hardness, and then, ground with a soft material such as buff, so that the surface of the developer carrier 6 has a roughened surface by a fine streak in the rotary shaft direction of the developer carrier 6, and only the vicinities of the top parts of the ruggedness of the roughened surface are made into a round cross section. Thus, in an initial stage that the developing device is started, a roughened surface state on the surface of the developer carrier is changed and the change in the sticking quantity of the developer is prevented.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a one-component developing device used in an image forming apparatus, which attaches a one-component developer to an electrostatic latent image and visualizes it. The present invention relates to a component developing device.

0002

[Prior Art] Conventionally, a developing device using a one-component developer includes a developer carrier that rotates to convey the developer, and a developer that regulates the developer attached to the developer carrier. and a developer regulating member forming a thin layer of the electrostatic latent image on the electrostatic latent image carrier in a development area where the developer carrier closely faces the electrostatic latent image carrier. There are known methods in which development is performed by attaching a chemical agent. Such developing devices include those using magnetic developers and those using non-magnetic developers. For example, developing devices using magnetic developers are disclosed in Japanese Patent Application Laid-open No. 54-51848 and Utility Model Application No. 58-146249. For example, there is a method using a non-magnetic developer as shown in Japanese Patent Application Laid-Open No. 60-53975.

In a developing device using a magnetic developer, the developer carrier is comprised of a rotatably supported cylindrical sleeve made of a non-magnetic material, and has a plurality of magnetic poles fixedly attached therein. have. The developer regulating member has a blade that contacts the surface of the developer carrier or a trimmer that is attached to protrude in close proximity to the surface of the developer carrier, and controls the amount of developer adsorbed on the surface of the developer carrier. is now regulated.

In such a developing device, the developer supplied from the developer supply means is attracted to the surface of the cylindrical sleeve by the magnetic pole in the developer carrier, and even when the cylindrical sleeve rotates, the magnetic pole does not move. Since a plurality of them are arranged along the circumference, they are conveyed while being maintained on the surface. The developer regulating member regulates the amount of developer adsorbed onto the developer carrier, and forms an even thin layer of developer on the surface of the developer carrier. The thin layer of developer is further conveyed to the development area, and due to the action of the development bias voltage applied to the developer carrier, the charged developer is transferred to the electrostatic latent image on the electrostatic latent image carrier. attached and visualized.

[0005] Furthermore, in a developing device using a non-magnetic developer,
A rotatably supported developer carrier, a developer regulating member (blade) pressed onto the developer carrier, and a supply means for supplying triboelectrically charged non-magnetic developer to the developer carrier. have.

[0006] In such a developing device, the developer supplied from the supply means is triboelectrically charged and adheres to the surface of the developer carrier, and is transported by rotation of the developer carrier. The developer regulating member rubs the developer adhered on the developer carrier with its contact pressure, thereby further triboelectrically charging the developer, and at the same time, regulates the amount of adhered developer to form a thin layer of developer. The thin layer of developer is transported to the development area, and is attached to the electrostatic latent image on the electrostatic latent image carrier by the development bias voltage applied to the developer carrier, so that the image is visualized.

In the above-mentioned developing device, the amount of developer that adheres to the surface of the developer carrier as a thin layer, which is regulated by the developer regulating member, affects the developer density. quantity must be ensured. For this reason, the surface of the developer carrier is made rough so that the developer can easily adhere to it. It is also known that the amount of developer adhered varies greatly depending on the condition of the rough surface, and generally, the higher the density of the unevenness of the rough surface and the greater the depth of the unevenness, the greater the amount of developer adhered.

Based on the above-mentioned properties, when manufacturing a developer carrier, the developer carrier is coated with a highly hard abrasive so that the density and depth of the unevenness will ensure a predetermined amount of developer adhesion. Polished in the axial direction to form a rough surface. Figure 4
2 is a schematic cross-sectional view showing an enlarged shape of the unevenness on the surface of the developer carrier formed as described above, and shows a cross section of the developer carrier in the circumferential direction. FIG. The density and depth of such unevenness can be adjusted by changing the particles of the abrasive material, but since the shape of the unevenness is due to small scratches formed by a highly hard abrasive material, many It has an acute angle.

[0009]

[Problems to be Solved by the Invention] However, the surface of the developer carrier is generally made of a material made by adding conductive material such as carbon to resin, and since this is a relatively soft material, it is difficult to interact with the developer. The state of the surface changes over time due to friction, contact pressure between the developer carrier and the developer regulating member that is in pressure contact with the developer carrier, and the like. As shown in Figure 5, this surface condition changes due to the material's unique condition, that is, the density and depth of unevenness according to the distribution of hard and soft areas caused by the inclusion of additives. It is thought that the state will converge to a state in which This surface change is large at a relatively early stage after the start of use, and there is a problem in that the amount of developer attached changes due to the change in surface condition, and the developer density changes over time.

[0010] In order to reduce this change over time, it is conceivable to finish the surface of the developer carrier so that it has a rough surface inherent to the material when manufacturing the developer carrier. It is necessary to polish the surface in a state close to that in actual use, which requires a lot of effort and time, making mass production impossible.

The present invention has been made in view of the above-mentioned problems, and it is possible to reduce the change in the amount of developer adhering to the surface of the developer carrier even when used for a long time, and to reduce the change in developer density over time. An object of the present invention is to provide a component developing device.

0012

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a rotatable device which is arranged opposite to an electrostatic latent image holder and which attaches a one-component developer to the surface and conveys it to a development area. a developer carrying member, a means for supplying developer to the developer carrying member, and a developer regulating member for regulating the conveyance amount of the developer attached to the developer carrying member, and the electrostatic latent image holding member In a one-component developing device that attaches developer to an electrostatic latent image on an electrostatic latent image holder and visualizes it in a development area where a body and a developer carrier face each other, the surface of the developer carrier is located approximately in the direction of the rotation axis. The surface has a rough surface due to fine scratches, and only the vicinity of the top of the unevenness of the rough surface has a rounded cross-sectional shape.

[0013] Furthermore, the method for manufacturing the one-component developing device described above can be modified by polishing the surface of the developer carrier in the axial direction with an abrasive material having a harder hardness than the material forming the surface.
It includes the step of forming a rough surface that can obtain an amount of developer adhesion that is equal to or more than the initial setting amount, and then polishing with a material that is less hard than the surface material until a rough surface that can obtain the initial set amount of developer adhesion is obtained. .

[0014]

[Function] In the one-component developing device according to claim 1, when developing an electrostatic latent image, the developer supplied from the developer supply means adheres to the surface of the developer carrier. is rotated and conveyed to a developing area facing the electrostatic latent image holder. At this time, since the surface of the developer carrier has a rough surface formed by fine scratches extending approximately in the axial direction, the developer adheres well, and the amount of developer required for development adheres.

When such development is repeated, the surface of the developer carrier is rubbed by the developer and the developer regulating member, and if there is an acute angle in the convex part of the rough surface, it will chip off. In the developing device, the protrusions of the rough surface formed on the surface of the developer carrier, that is, the vicinity of the top of the unevenness, have a rounded cross-sectional shape, and the sharp edges that are likely to chip off have been removed, so that the rough edges formed on the surface of the developer carrier have been removed. The change in the state of the surface of the developer carrier is reduced, and the change over time in the amount of developer attached to the surface of the developer carrier is also reduced.

In the method for manufacturing a one-component developing device according to claim 2, the surface of the developer carrier is polished in the axial direction with an abrasive material having a higher hardness than the material forming the surface, and the initial setting developer is Since a rough surface is formed that allows a larger amount of developer to adhere than the amount of adhesion, the rough surface formed here is due to many striations in the axial direction of the developer carrier, and the tops of the unevenness Both the bottom and the bottom have a cross-sectional shape with an acute angle. Further, the height of the unevenness is obtained only by polishing with a high-hardness abrasive material, and is larger than the height of the rough surface where the amount of developer adhesion is equal to the initial setting amount of developer adhesion. After that, the surface is polished using a material with lower hardness than the surface material of the developer carrier until the surface is rough enough to obtain the initial developer adhesion amount, so the sharp edges of the uneven tops are chipped off and a rounded cross-sectional shape is created. becomes. By chipping off the acute angle portion and removing small irregularities, the amount of developer adhesion is reduced, resulting in a rough surface on which the initial set amount of developer adhesion can be obtained. By forming a rough surface on the surface of the developer carrier in this manner, the developing device according to claim 1 can be easily obtained without much effort.

[0017]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. FIG. 1 is a schematic explanatory diagram showing the configuration of a one-component developing device that is an embodiment of the present invention.

A photoconductive drum 1, which is an electrostatic latent image holder, is capable of holding an electrostatic latent image 2, and a developing device 3 is provided facing the photoconductive drum 1. The developing device 3 includes a hopper 4 that stores developer (toner) T, and a magnet roll 5 that is rotatably supported around the hopper 4, which has a plurality of magnets fixed therein so as not to rotate. The developer carrier 6 includes a non-magnetic cylindrical developer carrier (sleeve) 6 and a developer regulating member (blade) 7 that regulates the amount of magnetic developer adhering to the surface of the developer carrier 6. The developer carrier (sleeve) 6 is placed close to the photoconductive drum 1, and the areas where their surfaces are close to each other serve as development areas. In addition, the multiple magnets arranged inside have S poles and N poles.
The magnetic developer is attracted to the surface of the developer carrier 6 by the magnetic field formed between adjacent magnetic poles, and can be transported. The developer regulating member 7 is made of an elastic member whose one end is fixedly supported.
The repulsive force of this elastic member causes the developer carrier 6 to
It is provided to press at 0g/cm2.

[0019] Such a configuration is effective in the width direction of the image to be formed (
1(a)), and the pressure with which the developer regulating member 7 presses the developer carrier 6 also has an equal value in the width direction of the image.

FIG. 1(b) is an enlarged schematic cross-sectional view showing the rough surface formed on the surface of the developer carrier of the developing device 3, and is a cross section taken in a direction perpendicular to the axis of the developer carrier 6. shows the shape of The unevenness having such a cross-sectional shape is formed by the axial striations of the developer carrier 6, and the surface roughness Rz
= 10 μm. Also, the acute angle portions are removed at the tops of the unevenness, resulting in a rounded shape, but there are acute angles near the bottoms of the unevenness.

In such a developing device, the one-component magnetic developer T stored in the hopper 4 is held on the surface of the developer carrier 6 by the magnetic force of the magnet roll 5, and the developer regulating member 7 Accordingly, the amount of developer adhering to the surface of the developer carrier 6 is controlled to 0.5 to 2 mg/cm2. As the developer carrier 6 rotates, this developer is sent to a development area where the photoconductive drum 1 and the developer carrier 6 face each other. A DC weight AC voltage is applied to the developer carrier 6 from an AC high voltage power supply 8 and a DC power supply 9, and the developer is attracted to the electrostatic latent image 2 on the photoconductive drum 1 in the development area and developed. be done.

At this time, the amount of developer attached to the developer carrier is controlled by the condition of the rough surface formed on the surface of the developer carrier and the developer regulating member. The surface of the developer carrier is rubbed by the developer and the developer regulating member 7 through repeated development, but in the above-mentioned developing device, the unevenness of the rough surface of the developer carrier 6 is rounded at the top. As a result, there are few changes in condition due to chipping of sharp corners. For this reason, the change in the amount of developer attached until the number of times of development is about 10,000 is small, and the change in the developed density is also small.

When the development is further repeated, the brittle parts of the material on the surface of the developer carrier are removed, and the hard parts also peel off accordingly. At this time, not only the tops but also the bottoms of the irregularities are worn away, and the small irregularities disappear and become irregularities according to the structure of the material. In such a state, the decrease in the amount of developer adhered due to the disappearance of small irregularities is offset by the increase due to the increase in the height of the irregularities due to wear of the bottom, and the change in the amount of developer adhered is slight. Along with this, there is also little change in development density.

FIG. 2 shows the results of developing 15,000 images using the one-component developing device of this embodiment and measuring changes in the amount of developer attached. The results are shown in comparison with the results obtained by forming a rough surface on the surface of the developer carrier. At this time, the developer contained 55% by weight of magnetic powder,
Containing 22.5% by weight of a styrene-dimethylaminoethyl methacrylate copolymer and polypropylene wax as a main binder, 22.5% by weight of a styrene-butadiene copolymer as a sub-binder, and furnace black type carbon. is used, with an average particle size of 11 μm.

The amount of developer adhered immediately after the start of use is set to be almost the same between the developing device of this embodiment and the conventional one, but the change in the amount of developer adhered in this embodiment is greater than that of the conventional one. At least, it is about 1/2 of the conventional one when developing 15,000 sheets. From the above results, it is confirmed that in the developing device according to the embodiment of the present invention, there is little change in the amount of developer attached when development is repeatedly performed many times.

FIG. 3(a) is a schematic structural diagram showing a one-component developing device according to another embodiment of the present invention, which uses a non-magnetic developer. In this device, a non-magnetic one-component developer is stored in a hopper 14.
A developer carrier 16 is provided at the opening facing the photoconductive drum 1 to which the developer is attached and conveyed. Further, in the hopper 14, a developer supply member (preload roll) 20 is provided that rotates in close proximity to or in contact with the developer carrier. The developer regulating member 17 that regulates the amount of developer adhering to the surface of the developer carrier 16 includes a spring plate 17a fixedly supported at one end and a soft elastic member 17b attached near the other end of the spring plate 17a. and has
This soft elastic member 17b is provided so as to be pressed against the developer carrier 16 with a predetermined pressure by the repulsive force of the spring plate 17a.

FIG. 3(b) is an enlarged schematic sectional view showing the rough surface formed on the surface of the developer carrier 16 of the developing device, and is a cross section taken in a direction perpendicular to the axis of the developer carrier 16. This shows the shape.

In such a developing device, the developer supply member 2
The developer is supplied to the developer carrier 16 by the rotation of the developer carrier 16, and the developer is conveyed to the position of the developer regulating member (blade) 17 by the rotation of the developer carrier 16. Here, the developer is formed into a predetermined uniform thin layer and triboelectrically charged, and the developer carrier 16 is sent to a development area facing the electrostatic latent image carrier 1. A DC weight AC voltage is applied to the developer carrier 16 from an AC high voltage power supply 8 and a DC power supply 9, and the developer is moved by the alternating electric field generated in the gap between the electrostatic latent image holder 1 and the developer carrier 16. It flies to the electrostatic latent image holder 1 and develops the electrostatic latent image. By repeating such development, the surface of the developer carrier 16 is coated with developer and the developer regulating member 1.
However, as in the first embodiment, since the unevenness on the surface of the developer carrier has a rounded top, there is little change in the condition of the rough surface of the developer carrier. ,
The change in development density is also slight.

Next, a method for manufacturing the developing device shown in FIG. 1 or 2, which is an embodiment of the invention as claimed in claim 2, will be described. The developer carrier used in the above developing device is
It is made of phenolic resin with carbon added as a conductive material, and is molded into a cylindrical sleeve. Its outer surface is polished axially using sandpaper. This polishing is done first with #320 sandpaper, then with #1 sandpaper.
Sand with 000 sandpaper. The rough surface formed by these polishing processes allows a developer adhesion amount of about 1.4 mg/cm<2> to be obtained.

[0030] Thereafter, this is polished with a buff. Although buffing has lower hardness than phenol resin, it can remove the sharp edges of the uneven tops formed on the surface. As a result, the rough surface formed on the surface becomes one with a small amount of developer adhesion, and when the rough surface becomes such that a predetermined amount of developer adhesion of 1.2 mg/cm2 can be obtained, polishing is performed. finish.

In polishing with the above-mentioned sandpaper, the rougher the sandpaper is used, the greater the depth of the unevenness becomes, making it possible to form a rough surface with a large amount of developer adhering. To obtain developer adhesion amount #
400 grit sandpaper is suitable. However, in this embodiment, a rougher material is used to form a rough surface that can obtain an adhesion amount greater than the initial setting value.

[0032] The other parts of the developer carrier and the other parts of the developing device can be manufactured using exactly the same method as the conventional method of manufacturing the developing device.

By such a method, it is possible to easily obtain a developing device as shown in FIG. 1 or 3, in which the amount of developer attached to the developer carrier is a predetermined initial setting value.

[0034] In the above method, the abrasive material used for the first polishing is not limited to sandpaper, but may have a hardness higher than that used for the cylindrical sleeve of the developer carrier, and can be used for polishing in the axial direction. Other abrasives can be used. In addition, the abrasive material used after polishing with a highly hard abrasive material is not limited to buffing, but is also made of a material such as cloth that has a lower hardness than the material used for the cylindrical sleeve, and is capable of chipping off the sharp edges of the rough surface. It's fine as long as it's possible.

[0035]

As explained above, in the one-component developing device according to claim 1, the surface of the developer carrier has a rough surface formed by fine striations extending approximately in the axial direction, and the surface of the developer carrier has a rough surface formed by fine striations extending approximately in the axial direction. Since the chisel has a rounded cross-sectional shape, even if it is rubbed by the developer and the developer regulating member, it is unlikely that a part of the convex part will chip off and fall off due to changes in the condition of the rough surface. Changes in concentration are reduced. In the method for manufacturing a one-component developing device according to claim 2, the surface of the developer carrier is polished in the axial direction with an abrasive material having a harder hardness than the surface material, thereby forming a rough surface. After making the surface rough enough to obtain a developer adhesion amount that is greater than the developer adhesion amount, the surface is polished with a material that is less hard than the surface material to form a rough surface that provides the initial set developer adhesion amount. A developing device that can obtain a predetermined amount of developer adhesion and that exhibits little change in developer density even when used repeatedly can be easily obtained without much effort and time.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural diagram showing a developing device that is an embodiment of the present invention, and a schematic cross-sectional view showing the state of a rough surface formed on the surface of a developer carrier.

FIG. 2 is a diagram illustrating changes in the amount of developer attached to a developer carrier when development is repeatedly performed using the developing device of the above embodiment in comparison with a conventional example.

FIG. 3 is a schematic structural diagram showing a developing device according to another embodiment of the present invention, and a schematic cross-sectional view showing the state of a rough surface formed on the surface of a developer carrier.

FIG. 4 is a schematic cross-sectional view showing the initial state of a rough surface formed on the surface of a developer carrier used in a conventional developing device.

FIG. 5 is a schematic cross-sectional view showing a rough surface formed on the surface of a developer carrier used in a conventional developing device, which has become a rough surface unique to the material due to multiple times of development. be.

[Explanation of symbols]

1 Electrostatic latent image holder 2 Electrostatic latent image 3 Developing device 4 Hopper 5 Magnet roll 6 Developer carrier (sleeve) 7 Developer regulating member (blade) 8 AC power supply 9 DC power supply 14 Hopper 16 Developer carrier ( Sleeve) 17 Developer regulating member (blade) T Developer

Claims (2)

[Claims] Claim 1: Disposed facing the electrostatic latent image carrier,
a rotatable developer carrier for transporting a one-component developer to a developing area with a one-component developer attached to the surface; a means for supplying the developer to the developer carrier; and an amount of the developer attached to the developer carrier. and a developer regulating member for regulating the electrostatic latent image on the electrostatic latent image carrier in a development area where the electrostatic latent image carrier and the developer carrier face each other to make the developer adhere to and visualize the electrostatic latent image on the electrostatic latent image carrier. A one-component developing device characterized in that the surface of the developer carrier has a rough surface with fine striations extending substantially in the direction of the rotation axis, and only the vicinity of the top of the unevenness of the rough surface has a rounded cross-sectional shape. Device 2. By polishing the surface of the developer carrier in the axial direction with an abrasive material having a higher hardness than the material forming the surface, a rough surface is obtained that can obtain a developer adhesion amount greater than the initial setting amount. 2. The production of a one-component developing device according to claim 1, further comprising the step of polishing the surface with a material having a lower hardness than the surface material until the surface becomes rough enough to obtain an initially set developer adhesion amount. Method