JPH09274380A - One-component developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent image over a long period, by preventing an overflow of the developer from an end part of a developing roller and clouding of the developer, in the developing device making a latent image on the image carrier visualized, with use of the one-component developer. SOLUTION: This device is provided with a toner electrification member 4 held in contact with the developing roller 2 across a thin film of the one- component developer on the developing roller 2, for electrifying the one- component developer by applying voltage between the toner electrification member 4 and the developing roller 2. In such a case, the toner electrification member 4 is composed, that the volume resitivity of a material forming the part held in contact with the visinity of a end part of the developing roller 2 is set < the volume resistivity of the part held in contact with the developing roller 2 within the image forming width. As a result, an electric discharging quantity from the toner electrification member 4 becomes larger, in the part held in contact with the visinity of the end part of the developing roller 2, therefore the electrification quantity of the toner on the developing roller 2 is raised corresponding thereto. Thus, adhesion of the toner can be made to be strong in the end part visinity of the developing roller 2.

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 electrophotographic image forming apparatus such as a copying machine or a printer, which visualizes a latent image formed on an image bearing member by adhering toner. In particular, it relates to a one-component developing device using a one-component developer.

[0002]

2. Description of the Related Art Conventionally, as a developing device for visualizing a latent image formed on an image bearing member such as a photoconductor by adhering toner, a device using a magnetic or non-magnetic one-component developer is known. . Such a one-component developing device is provided with a rotatable developing roller at a position facing the image carrier, and a toner layer is formed on the developing roller and conveyed to a position facing the image carrier. Then, a developing bias voltage is applied between the developing roller and the image carrier to form a developing electric field, and the toner on the developing roller is transferred to the latent image on the image carrier.

In the one-component developing device as described above, in order to attach the developer onto the developing roller and convey the developer, a method using magnetic force is used in the case of a magnetic developer, and static electricity is used in the case of a non-magnetic developer. The method used is adopted. However, in either case, when the developer attached to the peripheral surface is conveyed by the rotation of the developing roller, the developer also moves to some extent in the axial direction of the developing roller. For this reason, the developer jumps out from the end portion of the developing roller to cause developer spillage. In particular, when a non-magnetic developer is used, the adhesion to the developing roller is weak, and the developer is clouded at the end of the developing roller, causing a problem of scattering of the developer.

In order to prevent such a problem, for example, in Japanese Unexamined Patent Publication No. 61-28972, a seal member made of a fluororesin cloth is provided in the gap between the housing of the apparatus and both ends of the developing roller. There is proposed a developing device which is arranged so as to be in contact with the peripheral surface of the developer and mechanically prevents the developer from leaking from the end portion.

[0005]

However, the developing device as described above has the following problems. Since the sealing member is a flexible member and easily deformed with time, the developer leaks from the deformed portion. Therefore, it is difficult to prevent developer spilling for a long period of time. Further, there is a problem that frictional heat is generated at the contact portion between the seal member and the developing roller, the developer is melted and softened and fused to the seal member, and the developing roller is damaged.

The present invention has been made in view of the above problems, and an object thereof is to prevent developer spillage from the end of the developing roller and scattering of the developer outside the apparatus due to cloud formation. However, it is an object of the present invention to provide a one-component developing device capable of stably producing a good image for a long period of time.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 is such that an image carrier having a latent image formed on its surface by a difference in electrostatic potential is brought into proximity or contact with the image carrier. And a layer forming member that forms a thin layer of a one-component developer on the peripheral surface of the developing roller, and a developing region where the image carrier and the developing roller face each other is thin. In a one-component developing device for selectively transferring the layered one-component developer to the latent image to visualize the latent image, the one-component developer is in contact with the developing roller through a thin layer of the one-component developer. A toner charging member that charges the thinned one-component developer by a voltage applied between the developing roller and the developing roller, the developing device being outside the image forming width of the toner charging member. At least the part that contacts the end of the roller Shall volume resistivity of the material forming the near surface is smaller than the portion in contact with the developing roller in the image forming width.

According to a second aspect of the present invention, a developing roller is disposed so as to come close to or in contact with an image carrier on the surface of which a latent image due to a difference in electrostatic potential is formed, and a peripheral surface of the developing roller. A layer forming member that forms a thin layer of a one-component developer, and selects the thinned one-component developer for the latent image in a developing area where the image carrier and the developing roller face each other. In a one-component developing device that visualizes the latent image by transferring the latent image by contacting the developing roller through a thin layer of the one-component developer and applying a voltage applied between the developing roller and the developing roller. A toner charging member for charging the thin-layered one-component developer,
A portion outside the image forming width and in contact with the vicinity of the end portion of the developing roller is finished so that the surface roughness is rougher than a portion in the image forming width and in contact with the developing roller.

According to a third aspect of the present invention, in the one-component developing device according to the second aspect, a portion of the toner charging member outside the image forming width and in contact with the vicinity of the end of the developing roller is contacted. Is provided with a plurality of protrusions having a height of about 8 μm to 200 μm.

According to a fourth aspect of the present invention, a developing roller is disposed so as to come close to or in contact with an image carrier on the surface of which a latent image due to a difference in electrostatic potential is formed, and a peripheral surface of the developing roller. A layer forming member that forms a thin layer of a one-component developer, and selects the thinned one-component developer for the latent image in a developing area where the image carrier and the developing roller face each other. In a one-component developing device that visualizes the latent image by transferring the latent image by contacting the developing roller through a thin layer of the one-component developer and applying a voltage applied between the developing roller and the developing roller. A toner charging member for charging the thinned one-component developer, wherein the toner charging member comprises:
On the surface of the portion outside the image forming width and in contact with the vicinity of the end portion of the developing roller, there is a groove for moving the developer toward the central portion side in the width direction of the developing roller as the developing roller rotates. It has been formed.

According to a fifth aspect of the present invention, a developing roller is disposed so as to come close to or in contact with an image carrier on the surface of which a latent image due to a difference in electrostatic potential is formed, and a peripheral surface of the developing roller. A layer forming member that forms a thin layer of a one-component developer, and selects the thinned one-component developer for the latent image in a developing area where the image carrier and the developing roller face each other. In a one-component developing device for visualizing the latent image by transferring the latent image, there is a seal member which is made of a high resistance conductive member and is brought into pressure contact with the peripheral surfaces of both ends of the developing roller. Is applied with a voltage for charging the one-component developer on the developing roller.

According to a sixth aspect of the present invention, in the one-component developing device according to the fifth aspect, the contact surface of the seal member with the developing roller is provided with a developer as the developing roller rotates. It is assumed that a groove for moving the developing roller toward the central portion in the axial direction is formed.

According to a seventh aspect of the invention, in the one-component developing device according to the fifth or sixth aspect, the voltage applied to the seal member is an alternating voltage.
The toner charging member used in the above invention can be appropriately selected in shape and the like as long as it is a member that can generate electric discharge in the gap with the developing roller, and for example, a roller, a film, a blade or the like can be used.

The material for forming the toner charging member is, for example, carbon black as conductive fine particles,
A resin containing a metal such as magnetite, silver or copper can be used. Such a material is used as one having an appropriate volume resistance value by adjusting the content of carbon black or the like. Further, the surface layer of the toner charging member, which comes into contact with the developing roller, may be formed with a resin whose volume resistance is adjusted as described above.

The one-component developer used in the above invention is a magnetic or non-magnetic one-component developer. This one-component developer may be any method such as a pulverization method and a polymerization method, and if necessary, in addition to a black developer mixed with magnetite or carbon black, a color developer containing a color pigment is used. You can also

Since the present invention has the above-mentioned structure, it operates as follows. In the one-component developing device according to the first aspect of the present invention, the volume resistance value of the material forming the portion of the toner charging member that contacts the vicinity of the end of the developing roller contacts the developing roller within the image forming width. Since it is smaller than the portion, the amount of discharge from the toner charging member increases in the portion in contact with the vicinity of the end of the developing roller, and the amount of charge of the developer increases with this discharge. That is, the amount of charge of the developer attached near the end of the developing roller becomes higher than the amount of charge of the developer attached within the image forming width of the developing roller, and the developer and the developing roller near the end of the developing roller. It becomes possible to strengthen the adhesive force with. For this reason, it is possible to prevent the developer from clouding and to prevent the developer from leaking from the end portion of the developing roller.

In the one-component developing device according to the second aspect of the present invention, the surface roughness of the portion of the toner charging member that contacts the vicinity of the end portion of the developing roller has a portion that contacts the developing roller within the image forming width. Since the finish is made rougher, a portion having a gap in the contact area near the end portion of the developing roller increases, and discharge from the toner charging member easily occurs. Therefore, the charge amount of the developer attached near the end of the developing roller can be made higher than the charge amount of the developer attached within the image forming width of the developing roller. As a result, the adhesive force between the developer and the developing roller becomes strong in the vicinity of the end of the developing roller, and it is possible to prevent the developer from clouding and the developer from spilling. Further, on the surface of the toner charging member, as in the invention according to claim 3, the height is 8 μm to
It is desirable to provide a plurality of protrusions of about 200 μm. As a result, a gap suitable for stable discharge to be generated near the end of the developing roller is formed, and the developer is sufficiently charged to obtain good adhesion with the developing roller.

In the one-component developing device according to the fourth aspect of the present invention, the developer is applied to the surface of the portion of the toner charging member that comes into contact with the vicinity of the end portion of the developing roller to the central portion side in the axial direction of the developing roller. Since the groove to be moved is formed, the developer drops into the groove due to the pressure contact force between the toner charging member and the developing roller, and the developer is pushed by the rotation of the developing roller, and the developer is pushed along the groove toward the central portion side of the developing roller. Move to. This can prevent the developer from spreading in the axial direction and prevent the developer from leaking. Furthermore, it is possible to prevent clouding of the developer at the end of the developing roller.

In the one-component developing device according to the fifth aspect of the present invention, there is provided a seal member which is made of a conductive material having a high resistance and is brought into pressure contact with the peripheral surfaces of both ends of the developing roller.
Since the voltage is applied to the seal member, discharge occurs in the gap with the developing roller. As a result, the developer can be surely charged and the electrostatic adhesion force with the developing roller can be strengthened. Therefore, it is possible to prevent the developer from leaking and clouding.

In the one-component developing device according to the sixth aspect of the present invention, a groove for moving the developer toward the central portion in the axial direction of the developing roller is formed on the contact surface of the seal member with the developing roller. Therefore, by rotating the developing roller,
The developer spilled into the groove can be returned to the central portion side of the developing roller. Therefore, it is possible to prevent the developer from spreading in the axial direction and prevent the developer from leaking. Further, it is possible to suppress clouding of the developer at the end portion of the developing roller.

In the one-component developing device according to the seventh aspect of the invention, since an alternating voltage is applied to the seal member,
The developer reciprocates due to the alternating electric field formed between the seal member and the developing roller. Therefore, the state of motion of the developer on the developing roller becomes violent, the developer is prevented from remaining on the seal member, and fusion to the seal member can be prevented. Further, the developer swings in the groove to promote the movement of the developer and prevent the groove from being filled with the developer. Therefore, it is possible to stably prevent the developer from leaking over a long period of time.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a one-component developing device which is an embodiment of the invention described in claim 1. FIG. 2 is a schematic perspective view showing the developing roller and the toner charging member of this one-component developing device. This one-component developing device is provided at a position facing the image carrier 1 capable of forming a latent image on the surface due to a difference in charging potential,
In the housing 10, a developing roller 2 that closely faces the image carrier 1 and adheres toner to the surface of the developing roller 2 is conveyed, a layer forming member 3 that regulates the toner on the developing roller to form a toner layer, and a developing roller. A toner charging member 4 that applies an electric charge to the upper toner and a stirring supply member 5 that stirs the toner in the housing 10 and supplies the toner to the developing roller are provided. Further, a developing bias power source 6 that applies a developing bias voltage between the developing roller 2 and the image carrier 1, and a toner charging bias voltage between the toner charging member 4 and the developing roller 2. A developer charging power source 7 is provided. Further, as shown in FIG. 2, the end portion of the developing roller 2 is covered with a seal member 8 so as to cover a gap between the side surface portion of the layer forming member 3 and the housing 10 and the developing roller 2.
Are arranged.

The developing roller 2 is rotatably supported, and a voltage having the same polarity as the toner is applied from a developing bias power source 6. As a result, an electric field is formed between the developing roller 2 and the image carrier 1, and the toner is transferred to the image carrier 1.
It is designed to be transferred to the upper latent image. At this time, the image carrier 1 and the developing roller 2 are supplied from the developing bias power source 6.
The voltage applied between and is set to a DC voltage of about -50V to -700V or a DC superimposed AC voltage in which AC is superimposed on the DC voltage.

The layer forming member 3 is a blade in which urethane rubber is attached near the tip of a stainless steel plate spring,
Urethane rubber is supported so as to be pressed against the developing roller 2. The contact pressure of the layer forming member 3 is about 10 to 10.
The toner layer is set to about 0 g / cm, so that a toner layer of about 5 to 30 μm is formed on the developing roller 2.

The toner charging member 4 is a roller-shaped member supported so as to come into contact with the peripheral surface of the developing roller 2, and as shown in FIG. 3, silicone rubber is provided on the peripheral surface of the conductive core material 4a. An elastic layer 4b is formed by mixing carbon black as conductive particles. This elastic layer 4b
Is a portion where the volume resistance value of the material forming the portion (area B shown in FIG. 2) that contacts the outside of the image forming area of the developing roller 2 (see FIG. 2).
It is smaller than the area A) shown inside. That is, the conductivity of each part (region A and region B) of the elastic layer 4b is adjusted by increasing or decreasing the content of the carbon black. Further, in the portion A of the elastic layer 4b that comes into contact with the image forming portion, it is difficult to transfer to the image carrier 1 if the electrostatic adhesion between the developer and the developing roller 2 is too strong. The content of carbon black is adjusted so that the charge amount becomes. In this example, the developing roller 2
The volume resistance value of the portion B contacting the outside of the image forming portion is 1
The volume resistance value of 0 ³ to 10 ⁵ Ω · cm and the volume resistance value of the portion A of the developing roller 2 that contacts the image forming portion are set to 10 ⁶ to 10 ¹⁰ Ω · cm. In addition to the silicone rubber, EPDM rubber or the like can be used as the material of the toner charging member. Further, as conductive particles, magnetite,
It is also possible to use a metal powder such as copper or silver. A developer charging power source 7 is connected to the conductive core material 4a, and a DC voltage of about -1000V is applied.

The seal member 8 is wound around the developing roller 2 so as to fill the gap between the housing 10 and the layer forming member 3 and the end of the developing roller 2, and is made of a soft cloth, felt, urethane rubber or the like. Is formed of an elastic member. The seal member 8 reduces the leakage of the developer from the end portion of the developing roller 2, but it cannot be completely prevented by this alone, and the seal member 8 is not attached from the portion where the seal member 8 is not mounted. Toner leakage is also a problem.

The developer used in the above-mentioned developing device is a non-magnetic one-component toner, and a polar control agent such as a pigment or a metal-containing azo dye is contained in various thermoplastic resins such as styrene resin, acrylic resin or polyester resin. It is dispersed, ground and classified to a size of 3 to 20 μm. Further, a charge control agent is added to impart a negative charge. As the charge control agent, fine particles of 0.1 μm or less such as silica, alumina, and titanium which have been subjected to hydrophobic treatment are used, and hydrophobic silica is most preferable. A selenium photoconductor or an organic photoconductor is used as the image carrier 1, and the gap between the image carrier 1 and the developing roller 2 is 100 μm to 400 μm.
It is set to about μm, preferably about 150 to 300 μm.

In such a one-component developing device, the toner in the vicinity of the surface of the developing roller 2 passes through the position facing the layer thickness regulating member 3, and a thin layer of toner is formed on the developing roller 2 by the pressing force. . After that, the toner layer passes a position facing the toner charging member 4 by the rotation of the developing roller 2. When a voltage is applied between the toner charging member 4 and the developing roller 2, discharge is generated in these gaps. This discharge gives a negative charge to the developer on the developing roller 2, and the charge amount of the developer increases accordingly. At this time, since the electrical resistance of the portion B of the toner charging member 4 that contacts the end portion of the developing roller is smaller than the electrical resistance of the portion A that contacts the image forming area, the amount of discharge near the end portion of the developing roller. Will increase. Therefore, the charge amount of the developer becomes large near the end of the developing roller 2, a developer layer having a strong electrostatic adhesive force can be formed, and leakage of the developer can be prevented. Further, it is possible to prevent the developer from becoming a cloud and to prevent the developer from scattering outside the apparatus.

The toner layer on the developing roller 2 which has passed the position facing the toner charging member 2 is conveyed to the developing area facing the image carrier 1 by the rotation of the developing roller 2. Then, due to the developing electric field formed between the developing roller 2 and the image carrier 1, the toner on the developing roller is transferred to the latent image on the image carrier 1 for development.

When a long-time print test was conducted using the above-described one-component developing device, the developer leaked from the end of the developing roller and the scattering of the developer due to clouding of the developer, which has been a problem in the past, occurred. It was confirmed that it was excellent in maintainability.

FIG. 4 is a sectional view and a partial perspective view showing a toner charging member used in a one-component developing device which is another embodiment of the invention described in claim 1. The toner charging member 14 is provided with a semiconductive elastic body layer 14b around a conductive core material 14a, and a resin layer 14c mixed with conductive powder is formed on the peripheral surface of the elastic body layer 14b. Is. In the resin layer 14c, the volume resistance value of the portion B in contact with the outside of the image forming area of the developing roller 2 is
Is smaller than the portion A in contact with the image forming area. Carbon black or the like can be used as the conductive powder, and silicone resin, fluororesin, acrylic resin, phenol resin, polyurethane resin, polyester resin or the like can be appropriately selected and used as the resin.

In the toner charging member 14 as described above, the amount of discharge in the portion B that contacts the vicinity of the end portion of the developing roller increases, and the amount of charge of the developer increases, as in the above case. Therefore, it is possible to form a developer layer having a strong electrostatic adhesive force in the vicinity of the end portion of the developing roller 2, and it is possible to prevent the developer from leaking or forming a cloud.

FIG. 5 is a partial perspective view showing a toner charging member used in the one-component developing apparatus according to the second embodiment of the invention. The toner charging member 24 includes a conductive core material 24a and a semiconductive elastic body layer 24b formed around the conductive core material 24a. The surface roughness of a portion B of the elastic body layer 24b in contact with the vicinity of the developing roller end portion is roughened. Is rougher than the portion A in contact with the image forming area. In this example,
By selecting abrasive particles of an appropriate size and subjecting the outer peripheral surface of the elastic layer 24 to mechanical processing, rough unevenness is formed in the portion B that contacts the end portion of the developing roller. Further, in addition to this, the mold for forming the toner charging member 24 may be roughened.

In such a toner charging member 24, a minute gap is formed by the above-mentioned unevenness at the contact portion with the vicinity of the end portion of the developing roller, and discharge easily occurs. Therefore, the amount of charge of the developer that adheres to the vicinity of the end portion of the developing roller increases, and the electrostatic adhesion of the developer to the developing roller increases. A long-term print test was performed using a one-component developing device provided with such a toner charging member 24, and it was confirmed that there was no leakage of developer or cloud formation, and the maintainability was excellent. It was

FIG. 6 is a partial perspective view showing a toner charging member used in the one-component developing device according to the third embodiment of the present invention and an enlarged cross-sectional view near the end. The toner charging member 34 has a plurality of protrusions 34c formed on a portion B of the elastic layer 34b that contacts the end portion of the developing roller, and the height of the protrusions 34c is set to about 100 μm. This method of manufacturing the protrusion can be manufactured by providing irregularities on a mold or the like for manufacturing the toner charging member. In addition, there are a method of forming roughness by selecting abrasive particles of an appropriate size, a method of applying fine particles of a certain size to a material forming the surface layer and applying the fine particles to the surface of the toner charging member. To be

In such a toner charging member 34, a plurality of protrusions 34c form a minute gap in the contact portion with the developing roller, and discharge easily occurs, so that the charge amount of the developer attached near the end portion of the developing roller. Becomes higher. As a result, the electrostatic adhesion of the developer to the developing roller becomes strong, and the developer can be prevented from leaking or clouding. A long-term print test was performed using a one-component developing device provided with such a toner charging member 34, and it was confirmed that the developer did not leak and the maintenance was excellent.

Further, when the development is performed by changing the size of the protrusion of the toner charging member, in the case of 200 μm or more, the discharge is concentrated, so that the developer having a high charge amount is reduced, and many other developers are not. Since the amount of charge is low, clouding and leakage cannot be prevented. On the other hand, when the thickness is 50 μm or less, the discharge becomes weak, and a preferable charge amount of the developer cannot be obtained. Therefore, the size of the protrusion is 50 μm to 200 μm.
m is desirable.

FIG. 7 is a partial perspective view showing a toner charging member used in the one-component developing device according to the fourth embodiment of the invention. The toner charging member 44 is provided with a spiral groove 44c in the axial direction of the developing roller on the surface of a portion B that contacts the vicinity of the end of the developing roller. The cross-sectional shape of the spiral groove 44c may be such that the developer can pass through it, but the depth and width are preferably 200 times or more the average particle diameter of the developer. Further, in order to reduce the resistance during the transportation of the developer, it is preferable to coat it with a fluorine-based or silicone-based resin.

In such a toner charging member 44, the developer attached near the end portion of the developing roller is mechanically pushed into the groove 44c by the pressure contact force between the toner charging member 44 and the developing roller. Then, as the developing roller rotates, the developer in the groove 44c is pushed and moved to the central portion side of the developing roller. This prevents the developer from staying near the edge of the developing roller, and prevents the developer from clouding or leaking at the edge of the developing roller.
A long-term print test was carried out using a one-component developing device provided with such a toner charging member 44, and it was confirmed that leakage of the developer was prevented and the maintainability was excellent.

FIG. 8 shows claims 5, 6 or 7.
FIG. 3 is a schematic view showing a seal member used in the one-component developing device which is an embodiment of the invention described in FIG. This one-component developing device includes a seal member 54 wound around the peripheral surface of the developing roller 52 so as to come into pressure contact with the peripheral surface of the developing roller 52. As with the seal member 8 shown in FIG. It is arranged so as to prevent leakage of the developer between the housings of the apparatus or between the end portion of the developing roller and the layer forming member. The seal member 54 is made of a high resistance conductive member, and a voltage for charging the developer is applied to the seal member from a power source (not shown).
Further, a spiral groove 54c is provided in a portion of the seal member 54, which is in contact with the developing roller 52, in the axial direction of the developing roller.

The seal member 54 is made of silicone rubber,
An elastic member such as EPDM rubber mixed with conductive particles such as carbon black. The surface is coated with a nylon-based, styrene-based, or fluorine-based coating agent to reduce frictional resistance with the developer. Has been done. Also,
The groove 54c is set to have a depth and a width of 200 times or more the average particle diameter of the developer, and the developer can be moved to the central portion side of the developing roller 52 as the developing roller 52 rotates. It is a thing.

The voltage applied to the seal member 54 is an alternating voltage in which a DC component and an AC component are superposed,
In this example, the voltage of the AC component has a frequency of 0.5 kHz,
The peak-to-peak voltage is set to 1.0 kV.
Further, the voltage of the DC component is set to substantially the same potential as the DC component of the voltage applied to the developing roller or the average value of the applied voltage so that the toner may easily move alternately. The other configuration of the one-component developing device using the seal member 54 is the same as that of the one-component developing device shown in FIG.

In such a one-component developing device, the developer near the end of the developing roller 52 enters the groove 34c,
By the rotation of the developing roller 52, it moves in the groove 54c and is transferred to the central portion side. At the same time, an alternating electric field is formed between the seal member 54 and the developing roller 52, and the developer on the developing roller 52 vibrates according to the electric field. Therefore, the transfer of the developer in the groove is promoted, the clogging of the groove 54c is prevented, and the developer can be smoothly moved. Moreover, when the moving state of the developer was confirmed by changing the alternating voltage, the frequency of the AC component was 0.5 kHz or more, and the peak-to-peak voltage was 1.0 kV.
It was confirmed that preferable results were obtained as described above.

[0044]

As described above, in the one-component developing device according to the present invention, even if it is used for a long period of time, the inside of the image forming device and the image are not stained due to the clouding of the developer, and the image forming device is excellent. Image quality can be obtained. Further, the developer does not leak from the vicinity of the end portion of the developing roller, and a developing device having high maintainability can be realized.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a one-component developing device which is an embodiment of the invention described in claim 1.

FIG. 2 is a perspective view showing a main part of the one-component developing device.

3A and 3B are a sectional view and a partial perspective view showing a toner charging member used in the one-component developing device.

FIG. 4 is a sectional view and a partial perspective view showing a toner charging member used in a one-component developing device according to another embodiment of the invention described in claim 1.

FIG. 5 is a partial perspective view showing a toner charging member used in the one-component developing device according to the second embodiment of the invention.

FIG. 6 is a partial perspective view showing a toner charging member used in a one-component developing device according to an embodiment of the invention described in claim 3 and an enlarged cross-sectional view around an end portion.

FIG. 7 is a partial perspective view showing a toner charging member used in a one-component developing device according to an embodiment of the present invention.

FIG. 8 is a schematic perspective view and a cross-sectional view showing a seal member used in a one-component developing device according to an embodiment of the invention described in claim 5, claim 6 or claim 7.

[Explanation of symbols]

 1 image carrier 2, 52 developing roller 3 layer forming member 4, 14, 24, 34, 44 toner charging member 34c protrusion 44c groove 5 stirring supply member 6 developing bias power supply 7 developer charging power supply 8 side sealing member 10 housing 54 seal member 54c groove A portion in contact with image forming area B portion in contact with non-image forming area

Claims (7)

[Claims] 1. A developing roller disposed so as to come close to or in contact with an image carrier on the surface of which a latent image is formed due to a difference in electrostatic potential, and a thin layer of a one-component developer on the peripheral surface of the developing roller. A layer forming member that forms a layer, and selectively transfers the thinned one-component developer to the latent image in a developing area where the image carrier and the developing roller face each other, In a one-component developing device for visualizing a latent image, in contact with the developing roller through a thin layer of the one-component developer, by a voltage applied between the developing roller,
A toner charging member for charging the thin-layered one-component developer is provided, and a portion of the toner charging member outside the image forming width and in contact with the vicinity of the end of the developing roller is at least near the surface. The one-component developing device is characterized in that the volume resistance value of the material forming the is smaller than that of the portion in contact with the developing roller within the image forming width. 2. A developing roller which is arranged so as to be close to or in contact with an image carrier on the surface of which a latent image due to a difference in electrostatic potential is formed, and a thin layer of a one-component developer on the peripheral surface of the developing roller. A layer forming member that forms a layer, and selectively transfers the thinned one-component developer to the latent image in a developing area where the image carrier and the developing roller face each other, In a one-component developing device for visualizing a latent image, in contact with the developing roller through a thin layer of the one-component developer, by a voltage applied between the developing roller,
A toner charging member for charging the thinned one-component developer is provided, and a portion of the toner charging member outside the image forming width and in contact with the vicinity of the end portion of the developing roller has a surface roughness. Is finished so as to be rougher than a portion in contact with the developing roller within the image forming width. 3. The one-component developing device according to claim 2, wherein the portion of the toner charging member outside the image forming width and in contact with the vicinity of the end portion of the developing roller has a height of 8 mm.
A one-component developing device, characterized in that a plurality of protrusions having a size of from about μm to about 200 μm are provided. 4. A developing roller arranged so as to come close to or in contact with an image bearing member on the surface of which a latent image due to a difference in electrostatic potential is formed, and a thin layer of a one-component developer on the peripheral surface of the developing roller. A layer forming member that forms a layer, and selectively transfers the thinned one-component developer to the latent image in a developing area where the image carrier and the developing roller face each other, In a one-component developing device for visualizing a latent image, in contact with the developing roller through a thin layer of the one-component developer, by a voltage applied between the developing roller,
The toner charging member for charging the thin-layered one-component developer is provided, and the surface of the portion of the toner charging member that is outside the image forming width and is in contact with the vicinity of the end portion of the developing roller is A one-component developing device, characterized in that a groove is formed to move the developer toward the central portion side in the width direction of the developing roller with the rotation of the developing roller. 5. A developing roller which is arranged so as to be close to or in contact with an image carrier on the surface of which a latent image due to a difference in electrostatic potential is formed, and a thin layer of a one-component developer on the peripheral surface of the developing roller. A layer forming member that forms a layer, and selectively transfers the thinned one-component developer to the latent image in a developing area where the image carrier and the developing roller face each other, In a one-component developing device for visualizing a latent image, there is provided a seal member which is made of a high-resistance conductive member and is brought into pressure contact with the peripheral surfaces of both ends of the developing roller. A one-component developing device, wherein a voltage for charging a component developer is applied. 6. The one-component developing device according to claim 5, wherein the contact surface of the seal member with the developing roller is provided with a developer in the axial direction of the developing roller as the developing roller rotates. A one-component developing device characterized in that a groove for moving to the side of the unit is formed. 7. The one-component developing device according to claim 5, wherein the voltage applied to the seal member is an alternating voltage.