JPH1069162A - Nonmagnetic one-component developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the dispersion of a printing density and to reduce scratches caused by the contact of a developing roller with a toner supplying roller by providing an elastic foamed body layer and a skin layer on the toner supplying roller. SOLUTION: The toner supplying roller 30 constituted of the elastic foamed body layer 30a disposed therein and the skin layer 30b as the outer peripheral part is arranged in contact with the developing roller 8. Then, the roller 30 comes into contact with the developing roller 8 with an arbitrary width, in a contact part with the roller 8 and the roller 30 has the same rotational direction as that of the developing roller 8. Further, toner supplying bias supply 11 is connected to a shaft 9a and a bias voltage whose absolute value is higher than a developing bias voltage value is applied. The developing roller 8 has a single layer constitution; a metallic shaft 8a is used as a base material and a silicone rubber as a conductive elastic member is formed on the outer periphery of the shaft 8a. Then, developing bias supply 10 is connected to the metallic shaft 8a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-magnetic one-component developing apparatus using a non-magnetic toner as a developer in an electrophotographic apparatus or an electrostatic recording apparatus.

[0002]

2. Description of the Related Art Conventionally, electrophotographic apparatuses mainly use dry toner as a developer, and have been used in many copiers, laser printers, plain paper facsimile machines and the like, and have made remarkable developments. This electrophotographic apparatus is an apparatus to which an electrophotographic process technology is applied, and visualizes an electrostatic latent image formed on a photoconductor as an electrostatic latent image carrier with toner particles. Electrophotographic devices are classified into a one-component developing method and a two-component developing method. Unlike a two-component developing method, a non-magnetic one-component developing device does not require a mechanism for mixing, stirring, and controlling the toner concentration with a carrier. Therefore, it is advantageous for miniaturization and cost reduction.

Hereinafter, an electrophotographic apparatus using a conventional non-magnetic one-component developing apparatus will be described with reference to the drawings. FIG.
FIG. 1 is a sectional view of an electrophotographic apparatus using a conventional non-magnetic one-component developing device. In FIG. 3, reference numeral 1 denotes a metal drum such as aluminum as a base material, and a photosensitive receiving layer such as selenium (Se) or an organic photoconductor (hereinafter, referred to as OPC) is applied on the outer peripheral surface thereof in a thin film form. The photosensitive member 2 which is an electrostatic latent image carrier and the charger 2 disposed in close proximity to the photosensitive member 1 which is an electrostatic latent image carrier, 2a is a charging wire such as a tungsten wire, and 2b is a metal wire Shield plate, 2c grid plate, 3
Denotes an exposure optical system, and 4 denotes an exposure light beam emitted from the exposure optical system 3. Charged wire 2a, shield plate 2b, grid plate 2
In the charger 2 composed of C, the charging line 2a causes corona discharge, and uniformly charges the photoconductor 1 via the grid plate 2c. The exposure light beam 4 is obtained by subjecting an image signal to light intensity modulation or pulse width modulation by a laser driving circuit (not shown), and forms an electrostatic latent image on the photoconductor 1.

[0005] 5 is a developing hopper, 6 is toner stored in the developing hopper 5, 7 is a toner stirring member for stirring the toner 6, 8 is a toner carrier disposed in contact with or close to the photosensitive member 1. The developing roller 8a is a metal shaft that supports the developing roller 8 at both ends of the developing hopper 5, and 9 is disposed in contact with or close to the developing roller 8, and is stirred and transported by the toner stirring member 7. A toner supply roller 9a for supplying the toner 6 to the surface of the developing roller 8 and a metal shaft 9a supporting the toner supply roller 9 at both ends of the developing hopper 5 for rotation. The developing roller 8 and the toner supply roller 9 are made of a metal such as stainless steel as a base material, and elastic members such as urethane and silicon are formed in layers on the outer peripheral surface. Reference numeral 10 denotes a developing bias power supply connected to the shaft 8a and applying a developing bias voltage to the developing roller 8.
A toner supply bias power supply 11 is connected to the shaft 9a and applies a bias voltage to the toner supply roller 9.

Reference numeral 12 denotes a toner regulating blade; 12a, a metal spring plate member of the toner regulating blade 12; 12b, an elastic member such as silicon or urethane is integrally formed at one end of the metal spring plate member 12a, and comes into contact with the developing roller 8; The toner regulating member 13 is a blade holder to which the toner regulating blade 12 is fixed with screws.

The toner stirring member 7 conveys the toner 6 to the toner supply roller 9 while preventing aggregation of the toner 6 while drawing a circular locus along with the rotation of the toner supply roller 9. The toner 6 is supplied from the toner supply roller 9 to the developing roller 8 and is frictionally charged by the toner regulating blade 12 to form a thin layer on the outer peripheral surface of the developing roller 8. Next, the toner 6 is transferred and adhered to a portion of the photoconductor 1 where the electrostatic latent image is formed by the developing bias voltage applied from the developing bias power supply 10 to the developing roller 8 to visualize the electrostatic latent image. .

Reference numeral 14 denotes a paper cassette, 15 denotes paper as recording paper stored in the paper cassette 14, 16 denotes a half-moon-shaped paper feed roller for feeding out the paper 15 one by one from the paper cassette 14, and 17a and 17b denote a pair of upper and lower members. Transport roller, 1
Reference numeral 8 denotes a registration roller for temporarily stopping the paper 15 to make the paper 15 coincide with the toner image formed on the photoconductor 1, reference numeral 19 denotes a driven roller in contact with the registration roller 18, and reference numeral 20 denotes the photoconductor 1 , A transfer roller in which an elastic member is formed in a layer on the outer peripheral surface of a metal such as stainless steel as a base material, 20a is a metal shaft that supports the transfer roller 20 in a rotating shaft, and 21 is a shaft made of a metal. Connected transfer bias power supply, 22 is a toner collecting member, 23 is a fixing device for fixing the toner image transferred onto the paper 15, 2.
Reference numeral 4 denotes a heat roller provided in the fixing device 23 and having a heat source therein. Reference numeral 25 denotes a pressure roller in contact with the heat roller 24.

The paper 15 sent out by the paper feed roller 16
Is transported in the direction indicated by the mark A by the transport rollers 17a and 17b. Paper 1 temporarily with registration roller 18
When the toner image reaches the contact portion between the transfer roller 20 and the photosensitive member 1 with the rotation of the photosensitive member 1, the paper 15 reaches the contact portion in synchronization with the toner image. At this time, the metal shaft 20a of the transfer roller 20
By applying a high voltage from the transfer bias power supply 21 to the back surface of the paper 15, a charge having a polarity opposite to that of the toner 6 is applied to the back surface of the paper 15, whereby the toner image on the photoconductor 1 is transferred onto the paper 15. Next, the paper 15 is conveyed to the fixing device 23, and the toner image transferred onto the paper 15 is fixed by pressure and heat as the nipping rotation between the heat roller 24 and the pressure roller 25 is performed. Further, the residual toner after the development adhered to the outer peripheral surface of the photoreceptor 1 is collected by the toner collecting member 22.

[0009]

However, in the conventional non-magnetic one-component developing device, the magnetic force is not used for conveying the toner, but the electrostatic force and the physical force between the developing roller and the toner impose the toner on the developing roller. Since a thin layer of toner is formed, it is difficult to immediately supply the amount of toner required for development with one rotation of the developing roller. If the amount of toner corresponding to the amount of toner required for development is not supplied, the entire surface is A high-density image has a problem that the image density at the rear end of the printed image is reduced.

For this reason, a DC bias voltage is applied to the toner supply roller, and the electric field between the development roller and the toner supply roller is set so that the toner moves to the development roller side, thereby lowering the density of the trailing edge of the printed image. Had been prevented. However, the torque of the toner supply roller and the developing roller is increased, and the outer peripheral surface of the toner supply roller is made of a foamed elastic material. Therefore, the toner is easily clogged on the outer peripheral surface of the toner supply roller. There is a problem that the hardness of the outer peripheral surface is increased, which causes a change in image quality of a printed image and a lack of durability of the foam. Further, there is another problem that the friction between the developing roller and the toner supply roller damages the outer peripheral surface of the developing roller, thereby causing deterioration in the quality of a printed image.

Further, since the toner is charged by friction between the toner regulating blade and the toner supply roller, the toner layer formed on the developing roller is not consumed, and when the toner passes through the toner regulating blade a plurality of times, each time the toner layer passes through the toner regulating blade. However, there is a problem that the image density at the leading end of the printed image is reduced due to the increase in the charge amount.

Furthermore, the fluidity of the toner deteriorates due to the stress between the toner and the foam on the outer peripheral surface of the toner supply roller,
There has been a problem that the image quality of the printed image changes with the environmental change, and the quality of the printed image is unstable.

The present invention solves the above-mentioned conventional problems. A uniform printed image can be obtained, the durability of the toner supply roller is excellent, the torque of the toner supply roller and the like can be prevented from increasing, and the change in the environment can be prevented. It is an object of the present invention to provide a non-magnetic one-component developing device that prevents variations in a printed image.

[0014]

According to the present invention, there is provided a non-magnetic one-component developing apparatus according to the present invention, wherein a toner supply roller has the same elastic foam layer as an elastic foam layer disposed inside. Or a skin layer formed of a different elastic material.

Thus, it is possible to prevent an increase in torque of the toner supply roller and the like of the conventional non-magnetic one-component developing device, a change in image quality of a printed image, and the occurrence of damage to the development roller due to friction with the toner supply roller. Thus, the durability of the toner supply roller can be improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided a developing roller for forming a toner layer of a non-magnetic one-component developer on a surface thereof, and a developing bias voltage (V) applied to the developing roller.
b) a developing bias power supply, a toner supply roller that contacts the developing roller, pre-charges the toner and supplies the toner to the developing roller, and applies a bias voltage (Vsr) to the toner supplying roller. A toner supply bias power supply, a toner regulating blade for regulating a toner amount on the developing roller to form a thin layer, an electrostatic latent image carrier on which an electrostatic latent image is formed, and the electrostatic latent image carrier. A non-magnetic one-component developing device comprising: a toner collecting member that collects residual toner after development of the outer peripheral surface of the body, wherein the toner supply roller has an elastic foam layer disposed inside; A skin layer formed of the same or different elastic material as the elastic foam layer.

With this configuration, it is possible to prevent an increase in the torque of the toner supply roller and the like, to prevent the development roller from being damaged due to friction with the toner supply roller, and to improve the durability of the development roller and the quality of a printed image. Has an action.

Further, when the material of the elastic foam layer and the material of the skin layer are the same, the application of the bias voltage can be performed under the same conditions as in the past, and the control can be performed by the same process in manufacturing. On the other hand, when the material of the elastic foam layer and the material of the skin layer are different, there is an effect that the bias voltage can be applied under the same conditions as in the related art, and the wear resistance of the skin layer on the surface can be improved.

Here, as the elastic material, in addition to urethane rubber, silicon rubber, CR rubber, EPDM rubber, NB
R, NBR-epichlorohydrin, isoprene, butadiene and the like are used.

According to a second aspect of the present invention, there is provided a non-magnetic one-component developing apparatus according to the first aspect, wherein the elastic foam layer of the toner supply roller has conductivity. A bias voltage can be applied, so that the toner transportability can be improved, and the service life of the developing roller can be prolonged and the printing quality can be stabilized.

According to a third aspect of the present invention, there is provided a non-magnetic one-component developing apparatus according to the first or second aspect, wherein the toner supply bias power supply is a developing bias voltage (Vb) applied to the developing roller. ) Is applied to the toner supply roller, and |
Vb | ≦ | Vsr |.

Accordingly, when the toner is a positively chargeable toner, the relationship of Vb ≦ Vsr is satisfied, and when the toner is a negatively chargeable toner, the relationship of Vsr ≦ Vb is satisfied. The pulling force acts on the developing roller, and the toner can be transported onto the developing roller when an image is formed. In addition, there is an effect that the followability of the toner can be improved when the print image is entirely solid, and the density unevenness of the print image can be prevented.

According to a fourth aspect of the present invention, there is provided the non-magnetic one-component developing apparatus according to any one of the first to third aspects, wherein the elastic foam layer and the skin layer of the toner supply roller are provided. Has a compression set of 0.1% to 5%.

This has the effect that a uniform image can be obtained and that the density unevenness of the printed image can be prevented.

If the compression residual strain is higher than 5%, the stress with the developing roller tends to remain as a distortion on the toner supply roller, causing unevenness in the density of the printed image, and the compression residual strain is lower than 0.1%. This is because if it is too low, it is not possible to secure a bite amount with the developing roller.

According to a fifth aspect of the present invention, in the non-magnetic one-component developing device according to any one of the first to fourth aspects, the toner supply roller is arranged such that the toner supply roller is located at a central portion from a diameter of both ends. Is formed in a crown shape having a large diameter.

According to this configuration, the shortage of the NIP width at the center of the toner supply roller due to the distortion of the shaft of the toner supply roller can be solved.

Here, the difference between the diameter at the center and the diameter at both ends is 0.5 mm to 1.0 mm, particularly 0.8 mm to 1.0 mm.
0 mm is preferable from the viewpoint of preventing the density unevenness of the printed image.

According to a sixth aspect of the present invention, in the non-magnetic one-component developing apparatus according to any one of the first to fifth aspects, the toner supply roller has an Asker C of 1 ° to 1 °. It had a rubber hardness of 40 °.

This has the effect that the NIP width between the toner supply roller and the developing roller can be secured stably.

When the rubber hardness is higher than 40 °, the stress on the developing roller of the toner supply roller increases, and the torque of the developing roller increases. When the rubber hardness is lower than 1 °, a stable printed image can be secured. It is because it disappears.

According to a seventh aspect of the present invention, in the non-magnetic one-component developing device according to any one of the first to sixth aspects, the toner supply roller is configured to be 10 ⁵ to 10 ⁹ Ω.
Having the following resistance value.

Thus, a bias voltage can be applied to the toner supply roller, which has the effect of stabilizing the quality of a printed image.

The resistance value of the toner supply roller is 10
If it is less than ⁵ Ω, leakage occurs when a bias voltage is applied between the toner supply roller and the developing roller, and
^If it exceeds ⁹ Ω, the effect of moving the toner is lost even if a bias voltage is applied, so that the image quality of the printed image becomes unstable.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a 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 an enlarged sectional view of a toner supply roller according to the embodiment of the present invention. Elements that are the same as the conventional elements shown in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted.

Reference numeral 30 denotes a toner supply roller in the present embodiment, which is disposed in frictional contact with the developing roller 8. Reference numeral 30a denotes an elastic foam layer of the toner supply roller 30, and 30b denotes a skin layer provided on the outer periphery of the elastic foam layer 30a.

The difference from the conventional example is that the toner supply roller 3
0 has an elastic foam layer 30a and a skin layer 30b, and as shown in FIG. 1, the elastic foam layer 30a disposed inside the toner supply roller 30 and the outer peripheral portion thereof have the skin layer 30b. Is provided in contact with the developing roller 8, and contacts with an arbitrary width at a contact portion with the developing roller 8, and the rotation direction of the toner supplying roller 30 is the same as that of the developing roller 8. The direction of rotation. Further, a toner supply bias power supply 11 is connected to the shaft 9a, and applies a bias voltage (Vsr) having an absolute value larger than the developing bias voltage (Vb).

Hereinafter, an electrophotographic apparatus using the non-magnetic one-component developing device according to the present embodiment will be described.

The photosensitive member 1 is a negative charging type OPC, and is uniformly charged to -700 V by the charger 2. The developing roller 8 has a single-layer structure in which a metal shaft 8a is used as a base material and silicon rubber as a conductive elastic member is formed on an outer peripheral surface thereof, and has a resistance value of 10 ⁶ Ω. A developing bias power supply 10 which is a constant voltage power supply of -300 V is connected to the metal shaft 8a of the developing roller 8. here,
The rubber hardness of the developing roller 8 is preferably 30 ° to 60 ° from the viewpoint of preventing creep and punching, and the surface roughness of the developing roller 8 is desirably high when the surface is smooth so that a uniform thin toner layer can be formed. And 2 μmRz to 7 μmRz are preferred. The developing roller 8 in the present embodiment has a rubber hardness of 40 °,
The surface roughness is 3 μmRz.

The toner regulating blade 12 is made of an elastic metal spring plate member 12a such as a stainless steel plate or a phosphor bronze plate.
And a toner regulating member 12b integrally formed with urethane rubber having a rubber hardness of 60 ° as an elastic member at one end thereof, and is screwed to the blade holder 13. The toner regulating member 12b applies a linear pressure of 80 to the developing roller 8.
g / cm, and 0.5 mg / cm
cm ² of the toner layer. In the non-magnetic one-component developing device according to the embodiment, the toner layers on the developing roller 8 are formed from 1 to 3 and the density of the printed image is balanced. 0.6mg
/ Cm ² is preferred.

The toner 6 is a non-magnetic one-component toner.
This is a negatively chargeable toner in which carbon, wax, charge control agent and the like are uniformly dispersed in a polyester resin.

The transfer roller 20 includes a metal shaft 20.
A conductive foam is formed around a, and the resistance value is 10 ⁷ Ω. 4μA for metallic shaft 20a
, A transfer bias power supply 21 is connected.

In this embodiment, the potential difference between the toner supply roller 30 and the developing roller 8 is set by using two power supplies, the toner supply bias power supply 11 of the toner supply roller 30 and the developing bias power supply 10. However, it is also possible to use one of the toner supply bias power supply 11 and the developing bias power supply 10 to electrically change the output by voltage division by a resistor. Further, the present invention can be similarly applied to the positively charged photosensitive member 1 and the positively charged toner 6 instead of the negatively charged photosensitive member 1 and the negatively charged toner 6. Furthermore,
Although urethane rubber which is an elastic member is used as the toner regulating member 12b, silicon rubber, fluorine rubber,
Various rubber materials such as acrylic rubber, butadiene rubber, and EPDM rubber, various resin materials as rigid members, and metal members may be used. However, in order to prevent a change in the amount of the toner 6 adhered on the developing roller 8 with time, it is preferable that the wear resistance is excellent. Further, the developing roller 8 need not be limited to an elastic roller, but may be a metal roller or a resin roller, and the developing roller 8 and the photoconductor 1 may be arranged in a non-contact manner.

The printing operation of the electrophotographic apparatus using the non-magnetic one-component developing device according to the present embodiment configured as described above will be described.

After the photosensitive member 1 is uniformly charged to -700 V by the charger 2, the photosensitive member 1 is exposed by the exposure optical system 3, the surface potential of the exposed photosensitive member 1 is attenuated to -100 V, and the developing bias voltage is applied to the developing roller 8. (Vb) is applied to form a toner image on the photoconductor 1. A current of 4 μA flows from the transfer roller 20 to the sheet 15 to transfer the toner image, and the sheet 1 undergoes a fixing step generally known as an electrophotographic process.
5, the toner image is fixed.

[0046]

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

(Experimental Examples 1 to 4) In the electrophotographic apparatus using the non-magnetic one-component developing device according to the embodiment of the present invention, the shape of the toner supply roller 30, the residual compression, the physical properties such as the rubber hardness and the resistance value. , Skin layer 30b and elastic foam layer 30a
And the bias voltage (Vsr) of the developing roller 8 and the developing bias voltage (Vb) of the developing roller 8 to change the density difference between the leading and trailing end portions of the printed image and the toner supply roller before and after the printing operation. A test for the difference in torque and the damage generated on the developing roller was performed.

Here, the diameter of the central part of the toner supply roller 30 is φ1, the diameter of both ends is φ2, and the crown-shaped toner supply roller 30 is represented by a crown amount φ1−φ2.

As the electrophotographic process conditions for performing the printing operation, the process speed was set to 76 mm / sec, the peripheral speed of the developing roller 8 was set to 152 mm / sec, and the peripheral speed of the toner supply roller 30 was set to 106 mm / sec. Also,
A low-temperature / low-humidity environment in which the temperature and humidity are 10 ° C./20% RH (hereinafter referred to as L / L), a normal temperature / normal humidity environment in which the temperature and humidity are 20 ° C./60% RH (hereinafter referred to as N / N); 35 ° C
A printing operation test was performed in three environments of a high temperature / high humidity environment (hereinafter, referred to as H / H) of / 85% RH.

As a measuring method, a printing operation was performed under each environment, and a printing density difference between a front end portion and a rear end portion of a printed image was evaluated using a Macbeth densitometer. The difference between the initial torque of the toner supply roller and the torque of the toner supply roller after printing at 12K was measured using a torque meter. Furthermore,
The occurrence of scratches on the developing roller 8 after printing at 12K was also measured.

(Experimental Examples 5 to 8) In an electrophotographic apparatus using the non-magnetic one-component developing device according to the embodiment of the present invention, a positive toner having the same particle diameter as the negatively charged toner used in Experimental Examples 1 to 4 was used. Using a chargeable toner, the photosensitive member 1 is moved to +7 by the charger 2.
The test was performed in the same manner as in Experimental Examples 1 to 4 by uniformly charging to 00 V, exposing by the exposure optical system 3 and attenuating the surface potential of the photoreceptor 1 after exposure to +120 V.

(Comparative Examples 1 and 2) In an electrophotographic apparatus using the conventional non-magnetic one-component developing apparatus shown in FIG. 3, the outer peripheral surface of the toner supply roller 9 has a single layer structure of urethane rubber or EPD.
M rubber layer, and a bias voltage (Vs) is applied to the toner supply roller 9 by the toner supply bias power supply 11.
The test was performed in the same manner as in Experimental Examples 1 to 8 under the electrophotographic process conditions and measuring method when printing was performed by applying r). The developing bias voltage applied to the developing roller 8 was set to Vb.

Hereinafter, the process conditions of Experimental Examples 1 to 4 are shown in (Table 1), and the process conditions of Experimental Examples 5 to 8 and Comparative Examples 1 and 2 are shown in (Table 2).

[0054]

[Table 1]

As is clear from Table 1, in Experimental Example 1, the elastic foam layer 30a and the skin layer 30b are made of urethane rubber, and the resistance value of the toner supply roller 30 is 3 × 10 ^7.
Ω, the rubber hardness of the toner supply roller 30 is 3
5 °, the residual compression distortion of the toner supply roller 30 is 2%, the crown amount of the toner supply roller 30 is 0.07 mm, the developing bias voltage Vb is −300 V, and the bias voltage Vsr is −.
It was set to 400V.

In Experimental Example 2, the elastic foam layer 30a was urethane rubber, the skin layer 30b was CR rubber, the resistance value of the toner supply roller 30 was 5 × 10 ⁸ Ω, and the toner supply roller 3 was
0 is 35 ° in Asker C, the residual compression set of the toner supply roller 30 is 2%, the crown amount of the toner supply roller 30 is 0.05 mm, and the developing bias voltage Vb is −30.
0V and the bias voltage Vsr were set to -500V.

As an experimental example 3, the elastic foam layer 30a is made of urethane rubber, the skin layer 30b is made of silicon rubber, the resistance value of the toner supply roller 30 is 2 × 10 ⁷ Ω, and the rubber hardness of the toner supply roller 30 is 30 as Asker C. °, the residual compression distortion of the toner supply roller 30 is 3%, the crown amount of the toner supply roller 30 is 0.06 mm, and the developing bias voltage Vb is −
300 V and the bias voltage Vsr were set to -400 V.

In Experimental Example 4, the elastic foam layer 30a
R rubber, the skin layer 30b is urethane rubber, the resistance value of the toner supply roller 30 is 6 × 10 ⁶ Ω, and the toner supply roller 3
0 is 38 ° in Asker C, the residual compression set of the toner supply roller 30 is 1%, the crown amount of the toner supply roller 30 is 0.05 mm, and the developing bias voltage Vb is −35.
0V and the bias voltage Vsr were set to -500V.

[0059]

[Table 2]

As is apparent from Table 2, as Experimental Example 5, the elastic foam layer 30a is made of silicone rubber, the skin layer 30b is made of urethane rubber, the toner supply roller 30 has a resistance of 8 × 10 ⁵ Ω, and the toner The rubber hardness of the supply roller 30 is 32 ° in Asker C, the residual compression set of the toner supply roller 30 is 3%, and the crown amount of the toner supply roller 30 is 0.1.
0 mm, the developing bias voltage Vb was set to +350 V, and the bias voltage Vsr was set to +500 V.

In Experimental Example 6, the elastic foam layer 30a
PDM rubber, the skin layer 30b is urethane rubber, the resistance value of the toner supply roller 30 is 3 × 10 ⁸ Ω, the rubber hardness of the toner supply roller 30 is 30 ° in Asker C, the compression residual distortion of the toner supply roller 30 is 4%, When the crown amount of the toner supply roller 30 is 0.08 mm and the developing bias voltage Vb is +
350 V and the bias voltage Vsr were set to +500 V.

In Experimental Example 7, the elastic foam layer 30a was made of urethane rubber, the skin layer 30b was made of EPDM rubber, the toner supply roller 30 had a resistance value of 1 × 10 ⁹ Ω, and the toner supply roller 30 had a rubber hardness of Asker C of 20. °, the residual compression distortion of the toner supply roller 30 is 5%, the crown amount of the toner supply roller 30 is 0.07 mm, and the developing bias voltage Vb is +
300V and the bias voltage Vsr were set to + 450V.

In Experimental Example 8, the elastic foam layer 30a is made of silicone rubber, the skin layer 30b is made of EPDM rubber, the toner supply roller 30 has a resistance value of 3 × 10 ⁵ Ω, and the toner supply roller 30 has a rubber hardness of Asker C of 30. °, the residual compression distortion of the toner supply roller 30 is 2%, the crown amount of the toner supply roller 30 is 0.05 mm, and the developing bias voltage Vb is +
300V and the bias voltage Vsr were set to + 450V.

As Comparative Example 1, the negatively charged toner used in Experimental Examples 1 to 4 was used, the toner supply roller 9 was formed of a single layer of urethane rubber, and the resistance value of the toner supply roller 9 was 3 × 10 ¹⁰ Ω, the rubber hardness of the toner supply roller 9 is 45 ° with Asker C, the compression residual distortion of the toner supply roller 9 is 8%, and the crown amount of the toner supply roller 30 is 0 m.
m, the developing bias voltage Vb was set to -300 V, and the bias voltage Vsr was set to -450 V.

As Comparative Example 2, the positively charged toner used in Experimental Examples 5 to 8 was used, and the toner supply roller 9 was
The toner supply roller 9 has a resistance value of 7 × 10 ¹¹ Ω, the rubber hardness of the toner supply roller 9 is 42 ° in Asker C, the residual compression set of the toner supply roller 9 is 7%, and the toner is The crown amount of the supply roller 30 is 0 m
m, the developing bias voltage Vb was set to +300 V, and the bias voltage Vsr was set to +500 V.

As described above, as a result of the test of the density difference between the front end portion and the rear end portion of the printed image in which the entire surface of Experimental Examples 1 to 4 was made high in density,
The results of the test for the difference in torque between the toner supply roller before and after the printing operation and the results of the test for the scratches generated on the developing roller are shown in Table 3.
The results of the test of the density difference between the leading end portion and the trailing end portion of the printed image in which the entire surface of each of Experimental Examples 5 to 8 and Comparative Examples 1 and 2 were high in density were tested. The results of the test for the flaws generated on the developing roller are shown in (Table 4).

[0067]

[Table 3]

As is apparent from Table 3, in Experimental Examples 1 to 4, there is almost no difference between the density at the leading edge and the density at the trailing edge of the printed image in each environment. It has been found to prevent variations.

Further, it was found that the initial torque of the toner supply roller and the difference between the initial torque and the torque after the printing operation were small, and the increase in the torque accompanying the printing operation was prevented.

Further, it has been found that there is no flaw caused by the contact between the developing roller and the toner supply roller, and the stress on the developing roller can be reduced.

[0071]

[Table 4]

As is clear from Table 4, it was found that in Examples 5 to 8, even when a positively-charged toner was used, variations in print density were prevented as in Examples 1 to 4. did. In addition, it was also found that even when a positively charged toner was used, the initial torque and the increase in the torque difference of the toner supply roller before and after the printing operation were prevented as in Experimental Examples 1 to 4. Furthermore, even when a positively chargeable toner is used,
As in Experimental Examples 1 to 4, it was found that there was no flaw caused by the contact between the developing roller and the toner supply roller, and the stress on the developing roller could be reduced.

On the other hand, in Comparative Examples 1 and 2, the print density was varied due to environmental changes, and the printed image was unstable. Further, the difference between the initial torque and the torque of the toner supply roller before and after the printing operation was large, and the printed image was unstable. Further, the developing roller was damaged by the contact with the toner supply roller, streaks were formed in the printed image, and the printed image was unstable.

As described above, according to the present embodiment, since the toner supply roller has the elastic foam layer and the skin layer, it is less susceptible to environmental changes in temperature and humidity.
There is almost no density difference between the density at the leading edge of the printed image and the density at the trailing edge, preventing variations in the printing density, reducing the initial torque of the toner supply roller and the torque difference after the printing operation, and the toner of the developing roller. Scratches caused by contact with the supply roller could be reduced.

[0075]

As described above, in the non-magnetic one-component developing apparatus according to the present invention, the toner supply roller includes the inner elastic foam layer,
By having a skin layer made of the same or different elastic material as the elastic foam layer formed on the outer periphery of the elastic foam layer, a change in image quality of a printed image due to an environmental change and an increase in torque of the toner supply roller can be prevented. This prevents the developing roller from being damaged due to friction with the toner supply roller, thereby prolonging the life of the developing roller and providing a high quality image.

[Brief description of the drawings]

FIG. 1 is a cross-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 an enlarged sectional view of a toner supply roller according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view of an electrophotographic apparatus using a conventional non-magnetic one-component developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor 2 Charger 2a Charging line 2b Shield plate 2c Grid plate 3 Exposure optical system 4 Exposure light beam 5 Development hopper 6 Toner 7 Toner stirring member 8 Development roller 8a Shaft 9 Toner supply roller 9a Shaft 10 Development bias power supply 11 Toner supply bias Power supply 12 Toner regulating blade 12a Metal spring plate member 12b Toner regulating member 13 Blade holder 14 Paper cassette 15 Paper 16 Paper feed roller 17a Transport roller 17b Transport roller 18 Registration roller 19 Follower roller 20 Transfer roller 20a Shaft 21 Transfer bias power supply 22 Toner recovery Member 23 Fixing device 24 Heat roller 25 Pressure roller 30 Toner supply roller 30a Elastic foam layer 30b Skin layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuhiro Tsuru 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] A developing roller for forming a toner layer of a non-magnetic one-component developer on a surface thereof; a developing bias power source for applying a developing bias voltage (hereinafter referred to as Vb) to the developing roller; A toner supply roller for pre-charging the toner and supplying the toner to the developing roller; a toner supply bias power supply for applying a bias voltage (hereinafter, referred to as Vsr) to the toner supply roller;
A toner regulating blade that regulates the amount of toner on the developing roller to form a thin layer, an electrostatic latent image carrier on which an electrostatic latent image is formed, and after development of the outer peripheral surface of the electrostatic latent image carrier A toner recovery member for recovering the remaining toner of the non-magnetic one-component developing device, wherein the toner supply roller is the same as the elastic foam layer and the elastic foam layer disposed inside. And a skin layer formed of a different elastic material. 2. The non-magnetic one-component developing apparatus according to claim 1, wherein said elastic foam layer of said toner supply roller has conductivity. 3. The toner supply bias power supply applies a bias voltage (Vsr) having the same polarity as the development bias voltage (Vb) applied to the development roller to the toner supply roller, and | Vb | ≦ | 3. The non-magnetic one-component developing device according to claim 1, wherein the non-magnetic one-component developing device has a relationship of Vsr |. 4. The toner supply roller according to claim 1, wherein said elastic foam layer and said skin layer have a residual compression set of 0.1% to 5%. 2. The non-magnetic one-component developing device according to claim 1. 5. The non-magnetic toner according to claim 1, wherein said toner supply roller is formed in a crown shape having a diameter at a center portion larger than a diameter at both end portions. One-component developing device. 6. A toner supply roller comprising:
The non-magnetic one-component developing device according to any one of claims 1 to 5, wherein the non-magnetic one-component developing device has a rubber hardness of 0 to 40 °. 7. The toner supply roller according to claim ⁵ , wherein said toner supply roller is 10 ⁵ to 10 ⁹ Ω.
7. The resistance value having the following values:
The non-magnetic one-component developing device according to any one of the above.