JPH0764392A - One-component developing device - Google Patents

Abstract

PURPOSE:To eliminate trouble such as developing history and the scattering of toner, to maintain stable and excellent electrostatic charging property and to obtain excellent image quality for a long time by impressing bias voltage on at least one of plural toner layer thickness regulating electrostatic charging member'. CONSTITUTION:The layer thickness of toner 6 carried on the surface of a toner carrier 2 is regulated by a regulating electrostatic charging and fitting member 4 disposed as one of the toner layer thickness regulating electrostatic charging member so as to come in press-contact with the surface of the toner carrier 2, and the toner 6 carried on the surface of the toner carrier 2 is triboelectrified, so that sufficient charge may be applied to the toner 6. DC voltage whose polarity is reverse to the electrostatically charged polarity of the toner 6 is impressed on the member 4 by a bias power source 10 as necessary. Furthermore, the toner 6 carried on the surface of the toner carrier 2 is electrostatically charged by a conductive elastic rotating member 5 disposed as a 2nd toner layer thickness regulating electrostatic charging member at the V opening part of a developing device housing 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component developing device for visualizing an electrostatic latent image formed on a latent image carrier with toner in an image forming apparatus such as an electrophotographic copying machine. .

[0002]

2. Description of the Related Art Conventionally, as a developing device of this type, for example, JP-A-47-13088 and JP-A-53-16 are known.
As already disclosed in Japanese Patent No. 7341, etc., only the toner is conveyed to the latent image carrier by the toner carrier, and the electrostatic latent image on the latent image carrier is formed by the toner carried on the toner carrier. A one-component developing device for forming a visible image is known.

In this one-component developing device, as shown in FIG. 13, a toner supply member 101 is provided on the surface of a toner carrier 100.
The toner 102 is supplied by the toner carrier 10 and the layer thickness of the toner 102 carried on the toner carrier 100 is regulated by the regulation charging fixing member 103.
A toner layer having a predetermined thickness is formed on the surface of the toner. Then, the one-component developing device visualizes the electrostatic latent image formed on the latent image holder 104 by the toner 102 carried on the toner carrier 100, and the toner carrier in which the toner 102 is consumed is visualized. The toner supply member 101 is configured to supply the toner 102 to the body 100 again.

By the way, in the one-component developing device thus constructed, the development history of the thin toner layer formed on the toner carrier 100, the toner scattering from the developing region into the copying machine and the stable charging property of the toner. Maintenance (see Figure 14) is a challenge. That is, the development history means that the thin toner layer formed on the toner carrier is divided into a portion (developed portion) developed by the electrostatic latent image and a portion not developed (non-developed portion), and once developed. , A difference occurs in the toner thin layer thickness and toner chargeability between the developing portion and the non-developing portion,
This is a phenomenon in which an image history called a ghost occurs due to a difference in development characteristics in the next development process between the developing portion and the non-developing portion.

The development history will be described further. In the above-described one-component developing device, for example, non-magnetic one-component toner is reciprocated between the toner carrier and the latent image carrier by an alternating electric field for development. A toner that is once separated from the toner carrier and contributes to the development of the electrostatic latent image,
The toner is separated from the toner carrier and once returned to the toner carrier without contributing to the development of the electrostatic latent image. Therefore, when several tens of originals as shown in FIG. 15 are continuously copied, the particle size and charge distribution of the toner on the toner carrier differ between the image part and the non-image part, and the particle size distribution of the non-image part is generated. Is slightly smaller than the image area, and as a result,
5 Image history is generated as shown in the lower part. This is
This is because toner is selectively consumed in the developing process of the original image shown in the upper part of FIG.

Further, the toner scattering from the developing area is used for developing an electrostatic latent image on the latent image bearing member among the toner flying by the developing electric field in the area near the toner bearing member and the latent image bearing member. The non-chargeable toner that could not return to the toner carrier because it did not fall off would drop due to gravity or the flow of air due to the rotation of the toner carrier and the latent image carrier, resulting in toner contamination in the copying machine. .

As for the method of preventing the development history, the Japanese Patent Publication No. 1-49945 and Japanese Patent Laid-Open No. 6-94545 have been known.
The ones disclosed in JP-A-2-251771 and JP-A-2-127669 have already been proposed.

In the developing device disclosed in Japanese Patent Laid-Open No. 62-251771, the toner scraping member 110 is mechanically pressed against the surface of the toner carrier 100 after the developing process, as shown in FIG. The toner scraping member 110 allows the toner carrier 1 after the development process to be completed.
By temporarily scraping off all of the toner 102 on 00, the development history is prevented from occurring.

However, although the developing device according to this proposal uses the toner scraping member 110 that is in mechanical contact with the surface of the toner carrier 100, the external additive of the toner 102 strongly adhered to the toner carrier 100 is used. It has a problem that it is impossible to scrape off such fine particles. In this case, when the rising of the charging property of the developer immediately after being scraped off is examined, as shown in FIG. 17, the rising of the charging property of the developer is poor, causing fog in the background portion and the like, and for a long time. Depending on the use, there is a problem that the toner is mechanically deteriorated by the embedding of the external additive.

Further, in the developing device disclosed in Japanese Unexamined Patent Publication No. 2-127669, the electric field generating means is disposed in the housing, and the toner is once transferred from the toner carrier by the electric field, thereby preventing the development history. It is configured to do.

However, in the developing device according to this proposal, when the inventors of the present invention conducted an experiment using the same developing device, the electric field generating means was all disposed inside the housing, and therefore the toner carrier It has been confirmed that the toner transferred from is mixed with the toner in the storage portion of the housing, and the effect depends on the amount of toner in the developing device.

Further, as a developing device for preventing the toner from scattering, a developing device disclosed in Japanese Patent Application No. 2-218593 is proposed. In this developing device, as shown in FIG. 18, the toner scattering prevention plate 12 is provided on the downstream side of the developing device housing 120.
1 is provided, and the toner scattering prevention plate 121 is configured to prevent the toner 102 from scattering from the developing area between the latent image holding member 104 and the toner carrier 100 to the outside of the apparatus.

The developing device according to this proposal includes a latent image carrier 1
There is a slight amount of toner 102 carried out of the copying apparatus by the flow of air created by 04, and the toner 102 accumulated on the toner scattering prevention plate 121 to some extent spills into the copying machine.

Therefore, in order to solve these problems,
The present applicant has already proposed a one-component developing device as shown in Japanese Patent Application No. 3-185239.

As shown in FIG. 19, this one-component developing device supplies the toner 102 to the carrier 100, and the regulating member 1
In the one-component developing device for forming a thin layer of the toner 102 on the carrier 100 and giving an electric charge to the carrier 102, and sending the toner 102 to the holder 104 holding the electrostatic latent image, the electrostatic latent image is visualized. , Facing the carrier 100 and the holder 104 with a slight gap downstream of the carrier 100 as viewed in the moving direction of the carrier 104, and rotating in the same direction as the surface of the carrier 100. Conductive roll 130
Is configured to be provided.

[0016]

However, in the case of the one-component developing device according to the proposal shown in FIG. 19, as a result of the research conducted by the present inventors, it is insufficient to maintain the chargeability of the toner 102. I understood. The reason for the unstable charging property is that since the regulating member 103 is constantly in pressure contact with the toner carrier 100, it deteriorates the toner 102 and causes contaminants such as external additives to remain and contaminate the toner carrier 100 after development. However, it was difficult to maintain the chargeability, which caused fog on the background.

Further, a developing device using two or more additional members (members added for charging and layer formation) for increasing and maintaining chargeability is disclosed in Japanese Patent Laid-Open No. 58-57156. JP-A-57-30860, JP-A-56-40
It is disclosed in Japanese Patent Publication No. 863.

However, in the case of these developing devices, although the initial good charge is obtained by the pressure contact of the additional member with the toner, long-term maintainability cannot be obtained in terms of stress on the developer. There is. In addition, as for the non-contact additional member, there is no stress on the developer and it is stable, but the chargeability is insufficient, and there is no one that can achieve both good chargeability and maintainability, and there are many problems in image quality. It was

Further, even when only the rotating member is charged and the layer is regulated with respect to the toner carrier, it is necessary to perform the two functions at the same time. Therefore, the rotating member needs to be strongly pressed against the toner carrier. However, there is a problem in that the contact pressure between the two members causes bending, a uniform nip pressure cannot be obtained over the entire axial direction of both members, and good layer formation cannot be obtained over the entire axial direction. In addition, there is a problem in that the developer is stressed also in terms of the maintainability of chargeability, and it is difficult to use it for a long period of time. As for this problem, as shown in FIG. 15, the chargeability of the developer was similarly reduced. As described above, in the related art, there is no developing device which has no defect in image quality and has sufficient stable maintainability without contamination in the machine due to the toner cloud.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to achieve problems such as development history and toner scattering without secondary obstacles. SUMMARY OF THE INVENTION It is an object of the present invention to provide a one-component developing device that is capable of maintaining stable and good chargeability, can obtain a good image quality for a long period of time, and is small in size and can be manufactured at low cost.

[0021]

The above-mentioned technical problems are as follows.
In the developing device according to the present invention, the toner carrier is arranged in the vicinity of the electrostatic latent image carrier, the toner is supplied onto the toner carrier, and the toner triboelectrically charged on the toner carrier is thin. In a one-component developing device that forms a layer and develops the electrostatic latent image on the electrostatic latent image carrier by the toner layer formed on the toner carrier, the toner carrier is formed around the toner carrier. A plurality of toner layer thickness regulating charging members for frictionally charging the toner supplied to the toner and regulating the toner layer thickness are provided, and a bias voltage is applied to at least one of these toner layer thickness regulating charging members. Achieved by

As the toner layer thickness regulating charging member that comes into pressure contact with the toner carrier, for example, at least one fixed member and at least one movable member are provided, and a conductive elastic moving member is arranged on the most downstream side.

Furthermore, when a bias voltage is applied to both the fixed member and the movable member, for example, the polarities of the bias voltage of the DC component are made different.

The movable member is configured to rotate in the opposite direction of the toner carrier and to be applied with a bias voltage of a DC component having the same polarity as the toner.

Further, the movable member is configured to be provided with, for example, a toner peeling and pressing member that peels off the toner and also has a function of pressing the movable member against the toner carrier.

[0026]

In the present invention, around the toner carrier,
A plurality of toner layer thickness regulating charging members for frictionally charging the toner supplied onto the toner carrier and regulating the toner layer thickness are provided, and a bias voltage is applied to at least one of the toner layer thickness regulating charging members. Since the toner is supplied to the surface of the toner carrier,
A plurality of toner layer thickness regulating charging members that are always in contact with the surface of the toner carrier are sufficiently frictionally charged, and a sufficient amount of toner is used to form a thin layer, so that a hysteresis phenomenon can be prevented. Further, since the bias voltage is applied to at least one of the toner layer thickness regulating charging members, the bias voltage applied to the toner layer thickness regulating charging member charges the toner carried on the toner carrier. The amount can be increased, and also from this point, the occurrence of a hysteresis phenomenon or the like can be reliably prevented.

[0027]

First Embodiment The present invention will be described below based on the illustrated embodiment.

FIG. 1 is an overall explanatory view of a developing device using the non-magnetic one-component toner according to the present invention.

This developing device includes a housing 1 of the developing device.
The toner carrier 2, the toner supply member 3, the regulated charge fixing member 4, and the rotating member 5 disposed inside the main body constitute a main part thereof.

In the figure, reference numeral 1 denotes a housing of the developing device. Inside the developing device housing 1, toner 6 as a developer is supplied from a toner storage box (not shown) arranged outside the developing device. It is being supplied. As the toner 6, for example, a non-magnetic one-component toner is used, and various thermoplastic resins such as styrene resin, acrylic resin, polyester resin, etc. are used, and a polarity control agent such as a pigment such as carbon or a metal-containing azo dye is contained in the thermoplastic resin. Was dispersed and pulverized and classified to a size of 3 to 20 μm, and a charge control agent was externally added. Examples of the charge control agent include hydrophobically treated silica, alumina, titanium and the like.
Fine particles of 1 μm or less are used, but hydrophobic silica is most preferable.

At the opening of the developing device housing 1,
The toner carrier 2 is arranged so as to be rotatable in the arrow direction at a predetermined rotation speed, and the toner supply member 3 is rotated in the arrow direction in the housing 1 on the back side of the toner carrier 2. It is arranged to be rotatable at a speed. The toner supply member 3 is connected to a supply member bias power supply 7 for forming an electric field for supplying toner between the toner carrier 2 and the toner supply member 3. The toner 6 supplied into the developing device housing 1 is supplied from the toner supply member 3 to the toner carrier 2 by the electric field between the toner supply member 3 and the toner carrier 2 formed by the supply member bias power source 7. To be supplied to.

The toner carrier 2 usually has a diameter Φ of 5 to 5.
The surface roughness Ra is set to 40 mm by cutting a round bar or pipe made of aluminum or stainless steel, and then machining the circumferential surface by sandblasting, liquid honing, emery polishing, or by chemical corrosion. 0.1-
Although the one having irregularities of about 1.0 μm is used,
After cutting a round bar or pipe of aluminum or stainless steel, a semiconductive layer of phenolic resin or the like is provided on the circumferential surface, a coat layer of acrylic resin is formed, and polishing such as mechanical polishing is performed. = 0.1 to 1.0 μm
A material having a surface roughness of a certain degree is also used, and preferably Ra
= 0.2 to 0.4 μm is used as the surface roughness. Further, the aluminum roll may be mechanically polished and then subjected to anodizing treatment before use. The toner carrier 2
When a semiconductive layer is provided on the substrate, the volume resistance value in the thickness direction of the carrier surface layer is set to about 10 ⁵ to 10 ¹² Ωcm. Further, the rotation number of the toner carrier 2 is 100 to
It is set to 300 rpm. The developing bias applied to the toner carrier 2 by the bias power source 9 is normally −
100 superimposed with a DC bias voltage of 50 to -400V
The AC bias voltage is 0 to 4000 V _PP , the frequency of the AC bias is 1 to 5 kHz, and the value obtained by dividing V _{peak of the} AC bias voltage by the gap between the toner carrier 2 and the latent image carrier is 4 to 7 V. The frequency is 2.
It is used as 5 to 4.0 kHz.

On the other hand, the toner supply member 3 has a diameter Φ of 10 to 20 mm and is provided with several openings on the peripheral surface of an aluminum or stainless steel pipe having a wall thickness of 1 to 4 mm. The toner carrier 2 and the toner carrier 2 are arranged so as to face each other with a gap of about 0.5 to 2.0 mm and rotate at a peripheral speed about 1 to 5 times that of the toner carrier 2. Further, the supply member bias power supply 7 supplies a DC bias voltage of about 200 to 1000 V between the toner supply member 3 and the toner carrier 2, and the toner supply member 3 has the same polarity as the toner 6. Further, in order to prevent the toner 6 from filming on the surface of the toner supply member 3, a Mylar 8 or the like having a thickness of about 50 to 500 μm may be brought into contact with the surface of the toner supply member 3.

Further, inside the developing device housing 1, there is disposed a regulated charging fixing member 4 as one of the toner layer thickness regulating charging members so as to come into pressure contact with the surface of the toner carrier 2. The regulation charge fixing member 4 regulates the layer thickness of the toner 6 carried on the surface of the toner carrier 2, and at the same time, triboelectrically charges the toner 6 carried on the surface of the toner carrier 2 so as to give a sufficient charge. Is configured. As shown in FIG. 2, a DC voltage having a polarity opposite to the charge polarity of the toner 6 may be applied to the regulated charge fixing member 4 by a bias power source 10 as needed.

As the regulated electrostatic charge fixing member 4, for example, a plate spring made of stainless steel having a thickness of about 0.03 to 0.3 mm and vulcanized with Si rubber or EPDM rubber is used. Contact pressure is 10-100
Although it is set to about g / cm, it is preferably 60 g / cm or less in order to reduce stress on the toner 6. The rubber having a hardness of 20 to 80 degrees can be used, but a hardness of 30 to 50 degrees is preferable in order to reduce the stress on the toner 6. The toner 6 is formed into a thin layer of about 5 to 30 μm by the regulated charge fixing member 4 and is given a charge of about 2 to 20 μC / g. However, in order to reduce the stress of the toner 6 as much as possible, it is preferable to make the linear pressure as low as possible. Therefore, the lower limit value is determined from the relationship with the toner carrier 2. Further, in order to obtain the charging effect more effectively with the first-stage fixing member 4, there is a method of applying a DC voltage having a polarity different from that of the toner 6. However, when a voltage of different polarity is applied to the regulated charge fixing member 4, the resistance is set to 10 ³ to 10 ¹⁰ Ω from the effective range of bias leak and voltage.
cm, more preferably 10 ⁴ to 10 ⁷ Ωcm.

FIG. 3 shows a case where a DC voltage or the like having a polarity opposite to the charge polarity of the toner 6 is applied to the regulated charge fixing member 4 as shown in FIG. As is clear from the graph shown in FIG. 3, by applying a DC voltage having a polarity opposite to the charge polarity of the toner to the regulated charge fixing member 4, good chargeability of the toner can be obtained. In FIG. 3, “TRIBO” is a triboelectric charge amount, and “TV” is TR.
IBO Value and “WST” represent reverse polarity toner, respectively. The same applies to drawings other than FIG.

Further, in the opening of the developing device housing 1, as shown in FIG. 1, on the upstream side in the rotating direction of the toner carrier 2, a conductive elastic rotating member as a second toner layer thickness regulating charging member. 5 is rotatably arranged, and the conductive elastic rotating member 5 is configured to further charge the toner 6 carried on the surface of the toner carrier 2. In addition, the conductive elastic rotating member 5 has a DC power supply 1
1, a DC voltage having the same polarity as that of the toner 6 is applied, the toner 6 having the opposite polarity is attached to the rotating member 5, and only the well-charged toner 6 is carried on the surface of the toner carrier 2. . Further, the conductive elastic rotating member 5
A peeling pressure member 12 for peeling the toner from the surface of the conductive elastic rotating member 5 is pressed against the surface of the. The peeling pressure member 12 also serves to prevent the toner 6 from leaking outside from the opening of the developing device housing 1.

The conductive elastic rotating member 5 has a diameter Φ of 3
Approximately 20mm aluminum or stainless steel round bar with EPDM
Of a two-layer structure, such as one coated with a rubber material of which the surface is PFA coated, or one coated with silicone rubber or EPDM rubber with urethane, silicone rubber,
A one-layer structure type such as EPDM rubber is used.
The conductive elastic rotating member 5 is transferred to the surface of the rotating member 5 at a position facing the toner carrying member 2 by the toner carrying member 2.
And the peripheral speed of the conductive elastic rotating member 5 is 0.1 to 2.0 of that of the toner carrier 2.
It is set to double, preferably 0.2 to 0.8 times. The nip pressure between the conductive elastic rotating member 5 and the toner carrier 2 is about 100 g / cm or less, preferably 60 g / cm or less. Further, the resistance is 10 ³ to 10 ¹⁰ Ωcm, more preferably 10 ⁴ from the effective range of bias leak and voltage.
It is about 10 ⁷ Ωcm. By doing this, 10K
Good chargeability is exhibited even after C / V copying. Here, the rotating body 5 in this embodiment is provided with a scraper 12 as a peeling pressure member for scraping off the adsorbed toner 6, and the toner 6 adsorbed on the rotating body 5 is scraped off by the scraper 12 and developed. It is returned into the device housing 1. As the scraper 12, 0.05 to
A leaf spring made of stainless steel or the like having a diameter of about 0.15 mm or an edge of a urethane rubber blade contacted at a low pressure was used. As another function of the scraper 12, it has been difficult to press the rotating body 5 onto the toner carrier 2 uniformly, as in the related art.
As a measure against the flexure, good uniform pressure contact without flexure is obtained under the entire load on the rotating body 5. That is, the scraper 12 has a function as a member that uniformly presses the toner carrier 2 without bending the rotor 5.

Incidentally, FIG. 4 shows a case where a DC voltage having the same polarity as the charging polarity of the toner 6 is applied to the conductive elastic rotating member 5.
Shown in. As is clear from the graph shown in FIG. 4, the region in which the good carrying amount and the charging property of the toner 6 are obtained is when the DC voltage having the same polarity as the toner 6 is applied, and the reason is that the toner 6 is charged in the opposite polarity. This is because the formed toner 6 has been transferred to the rotating member 5. Further, when a DC voltage of opposite polarity is applied, the positively charged toner is transferred to the rotating member 5 and an appropriate amount of conveyance cannot be obtained, so that it is not in the actual use range.

Further, as the electrostatic latent image holding member 15 on which the electrostatic latent image is developed by the developing device constructed as described above, a Se-based photoconductor or an organic photoconductor is usually used. And the toner carrier 2 are usually 100 to 400 μm
It is arranged so as to face each other with a clearance of about 15 and is preferably 15
They are opposed to each other with a gap of about 0 to 300 μm.

1 and 2, reference numeral 16 denotes a seal member which prevents the toner 6 from leaking to the outside.

With the above structure, the one-component developing device according to this embodiment develops the electrostatic latent image formed on the latent image carrier 15 as follows. That is, as shown in FIG. 1, the developing device includes a housing 1 of the developing device.
Toner 6 as a developer is supplied from a toner storage box (not shown). The toner 6 supplied to the inside of the developing device housing 1 is supplied from the toner supply member 3 to the toner carrier 2 by the bias voltage applied between the toner carrier 2 and the toner supply member 3, and the toner 6 is supplied. The supplied toner 6 is carried on the surface of the carrier 2.

After that, the toner 6 supplied to the surface of the toner carrier 2 moves to the regulated charge fixing member 4 as the toner carrier 2 rotates. Then, the toner 6 carried on the surface of the toner carrier 2 is frictionally charged by the regulation charging fixing member 4 and is regulated to have a predetermined layer thickness. On the surface,
A thin layer of the toner layer charged to a predetermined polarity (negative polarity in this embodiment) is formed.

Further, the toner 6 on the toner carrier 2 whose frictional charge and layer thickness are regulated by the regulated charge fixing member 4 moves to the conductive elastic rotating member 5. Since the conductive elastic rotation member 5 is rotating in the direction opposite to the rotation direction of the toner carrier 2, the toner 6 carried on the toner carrier 2 is further frictionally charged, and the conductive elastic rotary member is also rotated. A DC voltage having the same polarity as the charging polarity of the toner 6 applied to the toner 5 is used to adsorb and remove the toner 6 charged to the opposite polarity.

By doing so, a thin layer of toner that is sufficiently frictionally charged by the regulated charge fixing member 4 and the conductive elastic rotating member 5 and is regulated to a predetermined layer thickness is formed on the surface of the toner carrier 2. , Is formed in a state where the opposite polarity charged toner 6 is removed.

Then, the thin layer of toner carried on the toner carrier 2 is conveyed to the developing area between the toner carrier 2 and the latent image carrier as the toner carrier 2 rotates. It In the developing area between the toner carrier 2 and the latent image carrier, an AC voltage in which a DC voltage is superimposed is applied by the bias power supply between the toner carrier 2 and the latent image carrier. The thin toner layer carried on the toner carrier 2 flies back and forth between the toner carrier 2 and the latent image carrier due to the alternating electric field formed by this bias voltage, and on the latent image carrier. The electrostatic latent image formed on the surface is developed with toner 6.

By the way, in the case of this embodiment, the rising of charging is improved and the toner thin layer is rearranged by passing through the regulated charging fixing member 4 and the rotating member 5.
There is no difference in the layer formation state corresponding to the image and non-image areas. Figure 5
Shows a graph comparing the rising of charging in the example of the present invention with the conventional example. As is clear from the figure, the rise of charging is significantly improved in this embodiment. As a result, the image history was eliminated.

After that, the toner carrier 2 after the development process is rotated in the direction shown by the arrow in FIG. 1 and the toner 6 which has not contributed to the development process is adsorbed and carried on the surface,
It rotates into the developing device hound jig 1. At this time, since the toner 6 is sufficiently frictionally charged and has a sufficient charge amount, even the toner 6 that has not contributed to the development of the toner carrier 2 due to the electric field formed by the toner carrier 2. It is surely adsorbed to the surface and does not scatter to the outside.

Experimental Example Next, in the example shown in FIG.
In order to confirm the stability of the effect of the present invention over time, a long-time print test was performed under the following conditions.
Image history did not occur even after 10,000 sheets, toner scattering was extremely small, toner layer was good, and fog did not occur.

Latent image carrier Negatively charged organic photoreceptor Process speed 160 mm / sec Toner carrier Φ24 mm, 180 rpm Phenolic resin roll (10 ⁶ Ωcm) Toner supply member Φ19 mm, 600 rpm Stainless steel roll (with opening) Toner regulation charging fixing member SUS303 , 0.12 mm thick leaf spring bonded with 1 mm thick EPDM rubber Contact pressure is about 120 gf / cm, resistance 10 ⁵ Ωcm Toner regulation charging rotary member Φ10 mm, 430 rpm EPDM rubber PFA coated resistance 10 ⁵ Ωcm, 50 mm / sec Reverse rotation with the carrier Latent image carrier, carrier gap Approx. 200 μm Toner regulating charging fixing member Approx. 30 g / cm and nip pressure of the carrier Toner regulating charging rotating member Approx. 30 g / cm Nip pressure of the carrier Latent image Potential -100V Background power -350V developing bias potential DC -200V to AC 2.4 kV _PP, 2 kHz superimposed toner regulating charging fixing member DC + 400V voltage applied toner regulating charging rotary member DC -400V applied voltage the toner non-magnetic one-component color toner (polyester)

Comparative Example In a conventional developing device as shown in the figure, in order to similarly confirm the stability over time, a long-term print test was performed under the same experiment conditions.

FIG. 6 shows the results of comparison between the initial charge and the chargeability after running when a running test of 10 KC / V (10,000 sheets) was carried out together with a comparative example.

As is apparent from FIG. 6, in the present invention, there was almost no difference in the charging property in the developing area, and no increase in the developer having the opposite polarity was observed. It was found that the developer having a lower charging property than that of the present invention and having a reverse polarity was significantly increased. 1 of this test
The toner in the developing device after 0KC / V was taken with an electron microscope (SE
M) As a result of comparison by photographs, it was found that in the case of the comparative example, the embedding of the external additive into the developer (toner) was severely deteriorated, but the embedding in the present invention was small. Further, comparing the same test with and without applying a bias to the fixing member as shown in FIG. 7, although there is a difference in the chargeability of the initials, no decrease in the chargeability is observed in both cases and the maintainability is improved. It turned out to be excellent.

Further, FIG. 8 is a graph showing changes in charging property and conveyance amount in the configurations of FIGS. 2 and 1 of the present invention.
As is apparent from both, the function separation is performed by the two pressure contact members, the transport amount is almost determined by the first fixing member 4, and at that time, the charging property is also shifted to a desired polarity side to some extent. It can be seen that the rotating member 5 has little change in the carry amount, removes the reverse polarity, and further improves the charging property. The reverse polarity developer attached to the rotating member 5 is developed by the blade 11 made of urethane rubber or EPDM having a blade-shaped rubber having a hardness of about 30 to 80 degrees applied to the rotating member 5. Agent 6 is scraped and removed.

Further, the rotating member 5 is attached to the toner carrier 2.
When the sheet is pressed, the nip width at the center portion is reduced, and a phenomenon such as an increase in the amount of conveyance or occurrence of charging failure occurs, so that the variation in the width direction is reduced. Therefore, by utilizing the scraper 11, it is possible to obtain a uniform contact pressure in the axial direction. FIG. 9 shows the relationship between bending and linear pressure in this configuration. Following the above test, 100KC /
When the V test was carried out, stable maintainability was exhibited without deterioration of chargeability, image quality defects, and cloud contamination inside the machine.

On the other hand, in the conventional developing device as shown in FIG. 13, in the developing section, new toner is supplied to the carrier from the supply member, and new thin layers of toner are successively generated by the regulated charge fixing member. Although it is formed, in the non-developing portion, a thin layer of toner once formed will pass through the regulated electrification fixing member again, and in the portion where the non-image portion continues for a while, new toner is not supplied, A thin layer of the same toner will pass through the regulating member many times. When the layer thickness of the toner on the carrier is measured, the layer thickness of the new thin layer of toner in the developing area is several microns higher than that in the non-developing area, and the charge amount of toner in the developing area is higher than that in the non-developing area. It was about several μC / g lower. Further, the toner in the non-developing area is larger than that in the developing area due to the adhesion of the toner to the carrier, which causes a difference in the flying property of the toner.
Due to these causes, for example, a print sample as shown in FIG. 15 is obtained.

That is, referring to FIG. 15, when looking at about 2/3 of the A4 size document after the start of printing, it is 3 × 1.
It is divided into a 0 cm rectangular solid black development area and a non-development area, and 15 x 5 cm in the latter half of the subsequent print.
There was a halftone dot image with an area ratio of 50%, and the copy density of the halftone dot image following the non-image part was slightly lower than that following the image part. This is because the chargeability of the toner on the carrier in the non-developing area is slightly higher than that in the developing area, and the toner on the carrier in the non-image area is less likely to fly than that in the developing area. This is because the amount of toner that reciprocates between the photoconductor and the developer carrying member is reduced, and the amount of toner for neutralizing the latent image charge of a halftone image is smaller than that in the developing unit.

Embodiment 2 FIGS. 10 to 12 show other embodiments of the present invention. The same members as those in the above embodiment are designated by the same reference numerals and explained. The configuration of the charging member arranged so as to contact the toner carrier is different from that of the first embodiment.

That is, in the embodiment shown in FIG. 10, the charging member provided on the upstream side of the toner carrier 2 is not a blade but a roll-shaped member 2 arranged in a fixed state without rotating.
It is formed by 0. In the embodiment shown in FIG. 11, the charging member provided on the downstream side of the toner carrier 2 is not a roll but a blade-shaped member 21, and the blade-shaped charging member 21 is the surface of the toner carrier 2. Is configured to reciprocate in the tangential direction.
Further, in the embodiment shown in FIG. 12, the charging member provided on the downstream side of the toner carrier 2 is formed by the endless belt-shaped member 22 instead of the roll, and the endless belt-shaped member 22 is rotated and moved. It is configured.

By doing so, FIGS.
Each combination as shown in 2 (rotating member, fixed member)
However, as a premise, it is possible if a low linear pressure is applied and an appropriate bias is applied, and stable maintainability can be exhibited without deterioration in charging property and defects in image quality.

The other structure and operation are the same as those of the above-mentioned embodiment, and the explanation thereof will be omitted.

[0062]

According to the present invention, which has the above-described structure and operation, problems such as development history and toner scattering can be achieved without secondary obstacles, and stable and favorable chargeability can be maintained. Therefore, it is possible to provide a one-component developing device which is capable of obtaining a good image quality for a long period of time and which is compact and can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a one-component developing device according to the present invention.

FIG. 2 is a configuration diagram showing a modified example of the same embodiment.

FIG. 3 is a graph showing a relationship between a bias application voltage, a toner charge amount, and a toner weight.

FIG. 4 is a graph showing a relationship between a bias application voltage, a toner charge amount, and a toner weight.

FIG. 5 is a graph showing a comparison between a toner charge amount and a toner weight in the present invention and a conventional example.

FIG. 6 is a graph showing a comparison between a toner charge amount and a toner weight in the present invention and a conventional example.

FIG. 7 is a graph showing a comparison between a toner charge amount and a toner weight depending on whether or not a bias is applied.

FIG. 8 is a graph showing a comparison between a toner charge amount and a toner weight in the present invention and a conventional example.

FIG. 9 is a graph showing the relationship between the linear pressure between the carrier and the rotating body and the amount of bending of the rotating body.

FIG. 10 is a main part configuration diagram showing another embodiment of the one-component developing device according to the present invention.

FIG. 11 is a main part configuration diagram showing another embodiment of the one-component developing device according to the present invention.

FIG. 12 is a main part configuration diagram showing another embodiment of the one-component developing device according to the present invention.

FIG. 13 is a block diagram showing a conventional developing device.

FIG. 14 is a graph showing a comparison between the number of copies and the toner charge amount and toner weight.

15A and 15B are explanatory views showing image recording samples, respectively.

FIG. 16 is a block diagram showing another conventional developing device.

FIG. 17 is a graph showing a toner charge amount and a toner weight.

FIG. 18 is a block diagram showing another conventional developing device.

FIG. 19 is a block diagram showing another conventional developing device.

[Explanation of symbols]

1 housing, 2 toner carrier, 3 toner supply member, 4 regulated charge fixing member, 5 rotating member.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Mikio Yamamoto 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (5)

[Claims] 1. A toner carrier is disposed in the vicinity of an electrostatic latent image carrier, toner is supplied onto the toner carrier, and a thin layer of triboelectrically charged toner is formed on the toner carrier. Then, in a one-component developing device that develops the electrostatic latent image on the electrostatic latent image carrier by the toner layer formed on the toner carrier, the toner is supplied around the toner carrier on the toner carrier. One-component development characterized in that a plurality of toner layer thickness regulating charging members for frictionally charging the toner and regulating the toner layer thickness are provided, and a bias voltage is applied to at least one of these toner layer thickness regulating charging members. apparatus. 2. The toner layer thickness regulating charging member that is in pressure contact with the toner carrier is provided with at least one fixed member and one movable member, and a conductive elastic moving member is arranged on the most downstream side. The one-component developing device according to claim 1. 3. The one-component developing device according to claim 2, wherein when a bias voltage is applied to both the fixed member and the movable member, the polarities of the bias voltage of the DC component are made different from each other. 4. The one-component developing device according to claim 2, wherein the movable member rotates in a direction opposite to that of the toner carrier and a bias voltage of a DC component having the same polarity as the toner is applied. . 5. The toner peeling / pressurizing member for peeling toner from the movable member and having a function of pressing the movable member against the toner carrier, is provided. One-component developing device.