JPH09106172A - Non-magnetic one-component developing device - Google Patents

Abstract

(57) Abstract: The variation in toner charge amount of the developing roller and the toner layer thickness on the developing roller due to changes in temperature and humidity is reduced, and uniform image characteristics and reliability with little influence of environmental changes are excellent. Another object is to provide a non-magnetic one-component developing device. SOLUTION: A developing roller 8 on which a non-magnetic one-component toner layer is formed and a developing bias voltage is applied, and a toner 6 is provided on the developing roller 8 in contact with the developing roller 8.
A non-magnetic one-component developing device 1 comprising: a toner supply roller 10 that rotates and supplies the toner; and a developing blade 13 that is disposed above the developing roller 8 and presses against the developing roller 8 to regulate the amount of toner. Toner supply roller 10 and developing roller 8
By providing the toner supply roller bias power supply 1A, which is a constant current power supply for applying a constant current between the two, the uniform image characteristics and high reliability can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-magnetic one-component developing device which can be detachably attached to an apparatus main body and visualizes an electrostatic latent image formed on a photoconductor with toner particles.

[0002]

2. Description of the Related Art In recent years, an electrophotographic apparatus mainly uses equipment using dry toner, and has been put to practical use as many copying machines, laser printers, plain paper facsimiles, etc., and is characterized by high resolution and high image quality. Has achieved.
This electrophotographic device is a device to which an electrophotographic process technology is applied, and visualizes an electrostatic latent image formed on a photoconductor with toner particles. As a developing device for an electrophotographic apparatus, a one-component developing device and a two-component developing device have been developed. Since the one-component developing device does not use a carrier as compared with the two-component developing device, it is necessary to pay special attention to the deterioration of the carrier and the mixing ratio of the carrier and the toner such as a device for detecting and controlling the developer concentration when developing. There is an advantage that it does not. Further, since no carrier adheres to the photoconductor during development, the photoconductor surface can be used to clean the residual toner on the surface of the photoconductor after the toner image visualized on the surface of the photoconductor is transferred to the copy paper. Does not scratch the surface. Thus, unlike the two-component developing system, the one-component developing device does not require a mixing mechanism with a carrier, a toner concentration control mechanism, or the like, and is therefore advantageous in reducing the size and cost of the developing device. Further, a one-component developing device is roughly divided into one using a magnetic toner and one using a non-magnetic toner, but it is simple and inexpensive for a magnetic one-component process that requires an expensive magnet roller with a complicated mechanism. The non-magnetic one-component process using the elastic roller is excellent in ease of use and cost. Therefore, at present, the electrophotographic apparatus using the non-magnetic one-component developing device is predominant.

A conventional one-component developing device will be described below. FIG. 2 is a schematic sectional view of an electrophotographic apparatus using a conventional non-magnetic one-component developing device. Reference numeral 1'denotes a conventional non-magnetic one-component developing device. Reference numeral 2 denotes a photoconductor, which is an electrostatic latent image carrier, having a metal drum of aluminum or the like as a base material, and selenium (Se) or an organic photoconductor (hereinafter referred to as OP) on the outer peripheral surface thereof.
A photosensitive receiving layer such as C) is formed in a thin film.
Reference numeral 2a is a shaft made of metal that rotatably supports the photoconductor 2, and 3 is a charger that is disposed in the vicinity of the photoconductor 2. The charging wire 3a is made of a tungsten wire or the like, and a metal shield plate. 3b and a grid plate 3c. Corona discharge is generated by the charging line 3a, and the surface of the photoconductor 2 is uniformly charged via the grid plate 3c. Here, an electrostatic latent image is formed on the photoconductor 2 by exposure light emitted from an exposure optical system (not shown), which is subjected to light intensity modulation or pulse width modulation of an image signal by a laser drive circuit (not shown). Is formed.

Next, 4 is a developing unit, the structure of which is shown below. Reference numeral 5 is a toner hopper which is a housing of the developing unit 4, 6 is toner stored in the toner hopper 5, and 7 is a toner stirring member which stirs the toner 6. The toner stirring member rotates in a circular locus and rotates in the toner hopper 5. Agglomeration of the contained toner 6 is prevented, and the toner 6 is conveyed to a toner supply roller 10 described later. Reference numeral 8 denotes a developing roller, which is a toner carrier that is disposed in the toner hopper 5 and is brought into contact with or close to the photosensitive member 2, and 9 is a seal at both ends of the developing roller, which is disposed at both ends of the developing roller 8. ,
The toner 6 is prevented from leaking from the developing unit 4. 1
0 is the toner 6 that is agitated and conveyed by the toner agitating member 7.
Is a toner supply roller for supplying to the surface of the developing roller 8. Further, the developing roller 8 and the toner supply roller 10 are made of metal such as stainless steel as a base material, and urethane,
An elastic member such as silicon is formed in layers and is rotatably supported on the housings on both sides of the toner hopper 5 by shafts 8a and 10a. A developing bias power source 11 applies a developing bias voltage to the developing roller 8. The toner 6 transfers the toner 6 to the portion of the photoconductor 2 where the electrostatic latent image is formed to make the electrostatic latent image visible. A toner supply bias power source 12 applies a constant bias voltage to the metal shaft 10a of the toner supply roller 10. 1
A developing blade 3 is in contact with the developing roller 8, and is an elastic member such as silicon or urethane integrally formed at one end of the metal spring plate member. 14 is a developing blade 1
3 is a mounting member for fixing the metal spring plate member 3 of the developing blade 13 and is fixed by screwing. Here, a constant voltage having the same polarity as the charging polarity of the toner 6 is applied to the toner supply roller 10 by the toner supply bias power source 12, and the absolute value of the bias voltage to the toner supply roller 10 is the same as that of the developing roller 8. It is set larger than the absolute value of the bias voltage. As a result, the toner supply amount from the toner supply roller 10 to the developing roller 8 and the toner charge amount are improved.

Next, other configurations will be described. 1
Reference numeral 5 is a copy sheet which is a recording medium stored in the copy sheet cassette, 16 is a half-moon-shaped sheet feeding roller for taking out the copy sheets 15 one by one from the copy sheet cassette, and 17a and 17b are copies taken out by the sheet feeding roller 16. A conveyance roller 19 for conveying the paper 15 and a registration roller 19 for temporarily stopping and waiting the copy paper 15 in order to make the copy paper 15 coincide with the toner image formed on the photoconductor 2, and a contact roller 20 for the registration roller 19. It is a driven roller. Reference numeral 21 denotes a transfer device for transferring the toner image formed on the photoconductor 2 to the copy paper 15, and includes a transfer line 21a made of a tungsten wire or the like and a shield plate 21b made of a metal plate. By applying a high voltage to the transfer line 21a, the transfer line 21a causes corona discharge, and the toner image on the photoconductor 2 is transferred onto the copy paper 15. A fixing device 22 is composed of a heat roller 22a having a heat source inside and a pressure roller 22b. The toner image transferred onto the copy paper 15 is pressed by the nip rotation of the heat roller 22a and the pressure roller 22b. It is fixed by heat. A cleaning blade 23 transfers the toner image on the photoconductor 2 to the copy paper 15 and scrapes off the residual toner on the photoconductor 2. Further, reference numeral 24 is a static eliminator, which is a photoconductor 2
After the upper toner 6 is transferred and cleaned, the residual charge, which is the electrostatic latent image remaining on the photoconductor 2, is removed.

The operation of the developing process of the electrophotographic apparatus using the conventional one-component developing apparatus configured as described above will be described below. First, the main body of the electrophotographic apparatus is turned on, the driving force is transmitted from the developing device driving unit (not shown) to the developing unit 4 together with the print signal, and the developing roller 8, the toner supplying roller 10, and the toner stirring member 7 are Figure 2
Rotate in the direction of arrow B shown in FIG. With the rotation of the toner stirring member 7, the toner 6 is conveyed onto the toner supply roller 10. The conveyed toner 6 is frictionally charged by the contact between the toner supply roller 10 and the developing roller 8, and the toner 6 adheres to the surface of the developing roller 8 by an electrostatic force to form a toner layer. The toner layer is carried by the rotation of the developing roller 8 while being carried on the surface of the developing roller 8 to the pressure contact portion between the developing roller 8 and the developing blade 13. The conveyed toner layer is subjected to a frictional action by the pressure between the developing roller 8 and the developing blade 13, and the triboelectric charge is further increased to form a uniform thin layer state. Further, the toner layer that has passed through the developing blade 13 forms a thin layer while maintaining the triboelectric charge amount and is conveyed to the contact position (developing region) with the photoconductor 2.
Here, the developing bias power supply 11 applies a bias voltage between the developing roller 8 and the photoconductor 2 to give a potential difference, and the toner layer is transferred to the electrostatic latent image formed on the photoconductor 2. The image is attached and a visible image is formed, and the development process is completed.

[0007]

In this non-magnetic one-component developing device, since the bias between the developing roller and the toner supply roller is controlled by the constant voltage control means for the toner supply roller, the temperature and Due to changes in the environment such as humidity, the resistance value of the conductive rubber formed on the outer circumference of the toner supply roller and the developing roller may change, and the conductivity may vary during manufacturing. The potential difference between the roller and the roller varies. As a result, variations in the toner charge amount of the developing roller and variations in the toner layer thickness due to changes in the toner supply performance to the developing roller occur, causing uneven density and fogging of the printed image.
It is required to obtain a printed image without density unevenness or fog.

The present invention reduces the variation in the toner charge amount of the developing roller and the toner layer thickness on the developing roller due to changes in temperature and humidity, and makes it possible to obtain a uniform printed image with little influence of environmental changes. Another object of the present invention is to provide a non-magnetic one-component developing device having excellent reliability.

[0009]

In order to solve this problem, a non-magnetic one-component developing device according to claim 1 of the present invention comprises:
A developing roller on which a non-magnetic one-component toner layer is formed and a developing bias voltage is applied, a toner supplying roller which is disposed in contact with the rear portion of the developing roller and rotates and supplies toner to the developing roller, and an upper portion of the developing roller. A non-magnetic one-component developing device having a developing blade arranged in a pressure contact with a developing roller to regulate the amount of toner, the constant current power source applying a constant current between the toner supplying roller and the developing roller. It has a configuration including.

As a result, the resistance value of the conductive rubber or the like formed on the outer peripheral portion of the toner supply roller or the developing roller or the variation in the conductivity at the time of manufacturing is accompanied by the environmental changes such as temperature and humidity. The occurrence of variations in potential difference between the developing roller and the toner supply roller is significantly reduced. As a result, the toner charging amount of the developing roller is made extremely uniform, the toner supply performance to the developing roller is stabilized, the toner layer thickness is made uniform, and the unevenness in density of the printed image and the variation in fog are significantly reduced. A uniform printed image with little influence of changes can be obtained.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A non-magnetic one-component developing device according to claim 1 of the present invention comprises a developing roller on which a non-magnetic one-component toner layer is formed and a developing bias voltage is applied, and Non-magnetic one-component developing provided with a toner supply roller disposed in contact with the rear portion to rotate and supply the toner to the developing roller, and a developing blade disposed above the developing roller and pressingly contacting the developing roller to regulate the toner amount. The apparatus is provided with a constant current power source for applying a constant current between the toner supply roller and the developing roller, and the outer circumference of the toner supply roller and the developing roller is accompanied by environmental changes such as temperature and humidity. It has an effect of remarkably reducing the occurrence of the variation of the potential difference between the developing roller and the toner supply roller against the variation of the resistance value of the conductive rubber or the like formed on the portion and the variation of the conductivity at the time of manufacturing. . As a result, the toner charge amount of the developing roller is made extremely uniform, the performance of supplying toner to the developing roller is stabilized, the toner layer thickness is made uniform, and the unevenness in density and fog of the printed image are significantly reduced. The quality and reliability can be improved.

According to a second aspect of the present invention, in the non-magnetic one-component developing device according to the first aspect, the constant current flowing from the toner supply roller to the developing roller has the same polarity as the charging polarity of the toner. The polarity of a constant current flowing from the toner supply roller to the developing roller is set to be the same as the charging polarity of the toner, which further stabilizes the toner supply performance from the toner supply roller to the developing roller. Has the effect of.

According to a third aspect of the present invention, in the non-magnetic one-component developing device according to the first or second aspect, the constant current power source performs control within a range of 1 μA ≦ I ≦ 1 mA, where I is a current value. Thus, there is an effect that an optimum toner charge amount can be secured.

A non-magnetic one-component developing device according to an embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic sectional view of an electrophotographic apparatus using a non-magnetic one-component developing apparatus according to an embodiment of the present invention. 1 is a non-magnetic one-component developing device of the present invention. 2 is a photoconductor, 2a, 8a, 10a is a shaft, 3 is a charger, 3a is a charging wire, 3b is a shield plate, 3
c is a grid plate, 4 is a developing unit, 5 is a toner hopper, 6 is toner, 7 is a toner stirring member, 8 is a developing roller, 9 is a seal on both ends of the developing roller, 10 is a toner supply roller, 11 is a developing bias power source, 13 is a developing blade,
14 is a mounting member, 15 is a copy paper, 16 is a paper feed roller, 17a and 17b are transport rollers, 18 is a copy paper transport path, 19 is a registration roller, 20 is a driven roller, 21 is a transfer device, 21a is a transfer line, 21b is a shield plate, 22 is a fixing device, 22a is a heat roller, 22b is a pressure roller,
23 is a cleaning blade and 24 is a static eliminator. Since these are the same as those in the conventional example, the same reference numerals are given and description thereof is omitted. What is different from the conventional example is that the toner supply bias power source 1A includes a developing roller 8 and a toner supply roller 1.
It serves to remarkably reduce the occurrence of variation in potential difference between the toner supply roller 10 and the developing roller 8 and is composed of a constant current power source for applying a constant current between the toner supply roller 10 and the developing roller 8. The polarity of a constant current flowing between the developing roller 8 and the developing roller 8 is the same as the charging polarity of the toner 6, and the constant current value I is in the range of 1 μA ≦ I ≦ 1 mA,
The point is that the current value is controlled to be constant within ± 10%.

Here, the fact that the polarity of the electric current is the same as the charging polarity of the toner means that the direction of the electric current flowing between the toner supply roller and the developing roller is the developing roller when the charging polarity of the toner is negative. Current to the toner supply roller,
When the charging polarity of the toner is positive, it means that an electric current is passed from the toner supply roller to the developing roller. In addition, the current value that is constantly controlled by the constant current source is ±
It is preferable to control within 10%. This has the effect of suppressing unevenness in density and fogging of the printed image and improving the printed image.

An electrophotographic apparatus using the one-component developing device of one embodiment of the present invention configured as described above,
The process conditions will be described below. The photoconductor 2, the developing roller 8 and the toner supplying roller 10 rotate in the direction of arrow B shown in FIG. 1, and the photoconductor 2 and the developing roller 8 and the developing roller 8 and the toner supplying roller 10 make frictional contact on the peripheral wall surface. It is in the state of. The photoconductor 2 is a negative charging type O
It is a PC and is uniformly charged to -700V by the charger 3. The developing roller 8 has a single-layer structure in which urethane rubber, which is a conductive elastic member, is formed on the outer peripheral surface of a metal base material, and has a resistance value of 10 ⁸ Ωcm. A DC voltage of -300V is applied to the shaft 8a of the developing roller 8 by the developing bias power source 11. The toner supply roller 10 has a single layer structure in which urethane rubber, which is a conductive foam, is formed around a metal shaft 10a, and has a resistance value of 10 ³ Ωcm.
It is. Further, a toner supply roller bias power source 1A, which is a constant current source, is connected to the shaft 10a, and the current value is 10
Control is performed so that the constant value is 0 μA. The toner supply roller 10 has a function of supplying the toner 6 supplied from the toner hopper 5 to the developing roller 8 and scraping off the toner 6 remaining on the developing roller 8 without being developed. The developing blade 13 is formed by integrally molding an elastic metal spring plate member such as a stainless plate or a phosphor bronze plate and urethane rubber having a rubber hardness of 60 degrees, which is an elastic member for regulating the amount of toner, at one end thereof. Mounting member 1
It is screwed to 4. The developing blade 13 presses the developing roller 8 with a linear pressure of 80 g / cm to uniformly form a 0.5 mg / cm ² toner layer on the surface of the developing roller 8. In the non-magnetic one-component developing device of this embodiment, the developing roller 8
The upper toner layer was set to have a range of 0.3 to 0.6 mg / cm ² . Toner 6 is a non-magnetic one-component toner, in which carbon, wax, a charge control agent and the like are uniformly dispersed in a polyester resin, and a negatively chargeable toner is used.

In this embodiment, as the material of the toner supply roller, conductive foam urethane rubber is used, but conductive EDPM, silicone rubber, SBR, NB are used.
R, nylon, vinyl, fluororesin, etc. can also be used. Although conductive urethane rubber was used as the material of the developing roller, silicone, phenol resin, fluororesin, epoxy resin SBR, NBR, or the surface of the developing roller coated with fluororesin, urethane resin, or the like is used. It can also be used.

The operation of the electrophotographic apparatus using the non-magnetic one-component developing apparatus of the embodiment of the present invention having the above-described structure will be described below. First, the photoconductor 2 is uniformly charged to −700 V by the charger 3, and then exposed by an exposure optical system (not shown) to reduce the surface potential of the photoconductor 2 after exposure to −100 V, and then the developing roller 8 is exposed. A developing bias is applied to -300 V to form a toner image on the photoconductor 2, and a current is applied from the transfer device 21 to the copy paper 15 to transfer the toner image, and the fixing step is generally known as an electrophotographic process. Then, the toner image is fixed on the copy paper 15.

[0020]

Next, specific examples of the present invention will be described.

(Experimental Examples 1 to 6, Comparative Examples 1 and 2) In an electrophotographic apparatus using the non-magnetic one-component developing apparatus according to one embodiment of the present invention, image characteristics (density and fog) due to temperature and humidity changes. Printing test was performed. In Experimental Example 1,
As electrophotographic process conditions for printing, the process speed is 80 mm / sec, the peripheral speed ratio of photoconductor 2 / developing roller 8 is 1.4, developing roller 8 / toner supply roller 10
The peripheral speed ratio of was set to 0.8. The diameter of the developing roller 8 is 2
The toner supply roller 10 having a diameter of 0 mm and the diameter of 16 mm was used, and the developing roller 8 and the toner supply roller 10 were assembled so that the contact length (nip width) between the outer peripheral surfaces in the rotation direction was 0.3 mm. As the measurement parameters, the materials of the developing roller 8 and the toner supply roller 10 are changed, and the constant current value flowing between the developing roller 8 and the toner supply roller 10 is changed for each material by using the toner supply bias power source 1A. It was For each constant current value, the temperature and humidity are
At room temperature / normal humidity (referred to as N / N environment) that is 20 ° C / 65% RH, at low temperature / low humidity (referred to as L / L environment) that is 10 ° C / 25% RH, at 32.5 ° C / 80% RH The experiment was conducted under three environmental conditions of high temperature / high humidity (referred to as H / H environment). As a measuring method, 1000 sheets were continuously printed three times in each environment, and the density was measured by a Macbeth densitometer and the fog was measured by a Hunter whiteness meter. As the image quality evaluation method, in the Macbeth densitometer, printing with a value variation of 0.05 or less is ◎, and 0.10 or less is ◯,
A value of 0.15 or less was evaluated as Δ, and a value of 0.15 or more was evaluated as x. In addition, in the Hunter whiteness meter, the print with variation of 0.10 or less is ⊚, 0.20 or less is ◯, 0.30 or less is Δ, and 0.
30 or more was set as x.

In Experimental Example 1, the material of the developing roller 8 is silicon, the resistance value is 10 ⁸ Ωcm, the material of the toner supply roller 10 is conductive urethane foam, and the resistance value is 10.
^The constant current value flowing from the toner supply roller 10 to the developing roller 8 was set to 1 μA at ⁴ Ωcm. In Experimental Example 2, the developing roller 8 is made of silicon and has a resistance value of 10 ⁶ Ωcm.
Then, the material of the toner supply roller 10 was set to conductive urethane foam, the resistance value was 10 ⁴ Ωcm, and the constant current value was set to 10 μA. In Experimental Example 3, the developing roller 8 is made of urethane, the resistance value is 10 ⁸ Ωcm, the toner supply roller 10 is made of conductive urethane foam, and the resistance value is 10 ³ Ωcm.
The constant current value was set to 100 μA. As Experimental Example 4, the material of the developing roller 8 is urethane, and the resistance value is 10 ⁶ Ωcm.
The toner supply roller 10 was made of conductive urethane foam, had a resistance value of 10 ⁵ Ωcm, and had a constant current value of 1 mA. In Experimental Example 5, the material of the developing roller 8 was silicon, the resistance value was 10 ⁸ Ωcm, the material of the toner supply roller 10 was conductive EDPM, the resistance value was 10 ⁵ Ωcm, and the constant current value was set to 1 mA. In Experimental Example 6, the material of the developing roller 8 is silicon, the resistance value is 10 ⁶ Ωcm, the material of the toner supply roller 10 is conductive EDPM, and the resistance value is 10.
^The constant current value was set to 1 μA at ³ Ωcm.

Further, as Comparative Example 1, the material of the developing roller 8 is silicon, the resistance value is 10 ⁸ Ωcm, the material of the toner supply roller 10 is conductive urethane foam, and the resistance value is 10 ⁵ Ω.
In cm, a constant voltage is applied to the toner supply roller 10 by using the toner supply bias power supply 12 for performing the constant voltage value control of the conventional example shown in FIG. 2 instead of the toner supply bias power supply 1A for performing the constant current value control of the present embodiment. Was biased and its constant voltage value was set to 450V. As Comparative Example 2, the developing roller 8
Made of urethane and has a resistance value of 10 ⁸ Ωcm, and the toner supply roller 10 is made of conductive urethane foam and has a resistance value of 1
The constant voltage value was set to 500 V at 0 ⁵ Ωcm.

The results of image quality evaluation of Experimental Examples 1 to 6 and Comparative Examples 1 and 2 are shown in Table 1.

[0025]

[Table 1]

As is clear from this (Table 1), in the experimental examples 1 to 6, the developing roller 8 and the toner supplying roller 10 are used.
When the constant current value control is performed between the developing roller 8 and the toner supply roller 10, the material and resistance value of the outer peripheral portions of the developing roller 8 and the toner supply roller 10 are not easily affected by the environmental change, and the density unevenness due to the environmental change of temperature and humidity is caused. It has been found that it is possible to significantly reduce the occurrence of variations such as fog and obtain extremely stable image characteristics. On the other hand, in the case of the constant voltage control in Comparative Examples 1 and 2, the image characteristics were unstable due to large variations in the density of printing and variations in fog due to environmental changes.

As described above, according to the present embodiment, the constant current control of the current value flowing between the developing roller and the toner supply rotor makes it less susceptible to environmental changes in temperature and humidity, resulting in uneven density, fog, etc. It was possible to remarkably reduce the occurrence of the above-mentioned phenomenon, obtain extremely stable image characteristics, and improve the reliability.

[0028]

As described above, according to the present invention, by providing the constant current power source for applying a constant current between the toner supply roller and the developing roller, the potential difference between the developing roller and the toner supply roller is increased. Occurrence of uneven density and fogging of the printed image by making the toner charge amount of the developing roller extremely uniform, stabilizing the toner supply performance to the developing roller, and making the toner layer thickness uniform. It is possible to obtain an advantageous effect that the image quality is significantly reduced and the reliability is excellent. Furthermore, by making the polarity of the constant current flowing from the toner supply roller to the developing roller the same as the charging polarity of the toner, it is possible to significantly stabilize the toner supply performance from the toner supply roller to the developing roller. Further, the constant current power supply sets the current value I to 1 μA ≦ I
By controlling to a constant value within the range of ≤1 mA, the optimum toner charge amount can be secured, and the advantageous effect of excellent image quality and reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an electrophotographic apparatus using a non-magnetic one-component developing device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of an electrophotographic apparatus using a conventional non-magnetic one-component developing device.

[Explanation of symbols]

 1 non-magnetic one-component developing device 1'non-magnetic one-component developing device 1A toner supply bias power source (constant current) 2 photoconductors 2a, 8a, 10a shaft 3 charger 3a charging line 3b shield plate 3c grid plate 4 developing unit 5 toner Hopper 6 Toner 7 Toner stirring member 8 Development roller 9 Seals at both ends of development roller 10 Toner supply roller 11 Development bias power supply 12 Toner supply bias power supply (constant voltage) 13 Development blade 14 Mounting member 15 Copy paper 16 Paper feed roller 17a, 17b Transport Roller 18 Copy paper conveyance path 19 Registration roller 20 Driven roller 21 Transfer device 21a Transfer line 21b Shield plate 22 Fixing device 22a Heat roller 22b Pressure roller 23 Cleaning blade 24 Static eliminator

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kazuhiko Noda 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A developing roller to which a non-magnetic one-component toner layer is formed and a developing bias voltage is applied to the developing roller, and a toner which is disposed in contact with the rear portion of the developing roller to contact and supply the toner to the developing roller. A non-magnetic one-component developing device comprising: a supply roller; and a developing blade that is disposed above the developing roller and presses against the developing roller to regulate the toner amount, the toner supplying roller and the developing roller. A non-magnetic one-component developing device comprising a constant current power source for applying a constant current between the developing device and the device. 2. The non-magnetic one-component developing device according to claim 1, wherein the constant polarity of the current flowing from the toner supply roller to the developing roller is the same as the charging polarity of the toner. . 3. The non-magnetic single component according to claim 1, wherein the constant current power source performs control within a range of 1 μA ≦ I ≦ 1 mA when the value of the current is I. Development device.