JPH01304475A - Single-component developing device - Google Patents

Abstract

PURPOSE:To obtain a copy image of excellent picture quality for a long period by making a specific expression hold for the toner flowing-in angle thetas to the surface of a developer carrier in an initial state by a soft elastic member provided at the contact part between a support body which has prescribed tensile strength and yield strength and the developer carrier. CONSTITUTION:A toner amount control member 7 consists of the support body 11 made of a spring material which has >=20kgf/mm<2> tensile strength and >=10 kgf/mm<2> yield strength and the soft elastic member 12 provided at the contact part between the support body 11 and developer carrier 14. Then the soft elastic member 12 is so shaped that the expression I holds for the toner flowing-in angle thetas between its flowing-in side flank and the developer carrier surface in the initial state. In the expression, (r) is the radius of the developer carrier and (t) is the thickness of the soft elastic member. Further, the width LR of the soft elastic member is so determined that 1/2lN<=LR<=4lN, where lN is the initial contact width of the developer carrier. Consequently, a toner layer is obtained stably on a developing sleeve for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a one-component developing device for developing an electrostatic latent image using a one-component toner.

BACKGROUND OF THE INVENTION In electrophotography, the cascade imaging method, magnetic brush development method, and liquid development method are well known as methods for developing electrostatic latent images.

On the other hand, another important developing method is the US special kitsuki 2,895.
A transfer development method using a toner carrying member called a donor is disclosed in the specification of No. 847. The transfer development method described in this patent specification includes (1) a case in which the toner layer and the photoconductor are not in contact and the toner flies through this gap, 2) a case in which one layer of toner is in rotational contact with the photoconductor, and 3) This is a general term for cases in which layers 1 to 4 come into contact with the photoreceptor and slide across the image area, and is also well known as the touchdown imaging method.

As one-component developing devices using the touchdown development method, devices using magnetic toner and devices using non-magnetic toner are known.

FIG. 14 is a schematic diagram of an example of a magnetic component device.

In FIG. 14, 1 is a photoconductive drum (electrostatic latent image carrier) capable of holding an electrostatic latent image 2, and a developing device is disposed close to a position facing the photoconductive drum 1. There is. This developing device has a hopper 3 for storing a magnetic one-component developer 4, and a magnet roll 5 in which a plurality of magnetic poles fixed so as not to rotate are arranged alternately. a non-magnetic cylindrical developing sleeve 6 rotatably supported around the developing sleeve 5;
Attaching @Developing sleeve 6 to regulate the amount of magnetic toner
The developing sleeve 6 and the toner amount regulating member 7 are arranged in the hopper 3, and the developing sleeve 6 is arranged in the developing area on the photoconductive drum. It is located close to 1.

In such a developing device, the magnetic - component developer 4 stored in the hopper 3 is held on the surface of the developing sleeve 6 by the magnetic force of the magnet roll 5, and the toner amount regulating member 7 causes the toner component developer 4 to be held on the surface of the developing sleeve 6 by the toner amount regulating member 7. The amount of attached toner is 1 (nl/c
After being regulated by rtx, the rotation of the developing sleeve 6 causes the photoconductive drum 1 and the developing sleeve 6 to be sent to the opposing developing area. A DC superimposed AC voltage is applied to the developing sleeve 6 from an AC high voltage power source 8 and a DC power source 9, and the photoconductive drum 1 is Upper electrostatic latent image 2
The structure is such that the image is developed using a magnetic component developer. (For example, Japanese Unexamined Patent Publication No. 54-51848, Utility Model Application No. 58-1
462119, U.S. Pat. (Japanese Patent Application Laid-Open No. 60-53975).

In this device, a non-magnetic one-component developer 4 is placed in a hopper 3.
The -component developer 4 is supplied to the developer carrier 14 by a supply roll 13 rotating in the direction of the arrow at the same circumferential speed as the developer carrier 14.

A spring member 11 is placed on the developing sleeve 6 of the developer carrier 14.
and a soft elastic member 12 of the toner amount regulating member 7 are provided so as to be in contact with each other under a predetermined pressure. The one-component developer 4 supplied to the developer carrier 14 is conveyed to the position of the quantity regulating member 7 by rotation of the developer carrier, and is formed into a predetermined uniform thin layer and is charged with a predetermined charge. After being applied, it is sent to a position opposite to the semiconductive drum 1 (development area). An alternating voltage is applied to the developer carrier, and due to the alternating electric field generated in the gap between the semiconductive drum 1 and the developer carrier 14, the developer flies to the semiconductive drum 1 and is electrostatic latent. The image is developed.

Problems to be Solved by the Invention In such a one-component developing device, the life of the toner amount regulating member is determined by the thickness of the soft elastic member and the degree of friction. However, simply increasing the thickness of the soft elastic member increases the contact area with the developing sleeve as well as the friction of the soft elastic member, reducing the effective pressing force, resulting in an increase in the amount of toner adhering to the developing sleeve, resulting in uneven toner adhesion. A stable toner layer cannot be obtained. In addition, even if the contact width of the soft elastic member is limited in order to prevent the contact area from increasing, as wear progresses, the pressure contact stress at the toner inflow section increases, preventing the toner from entering, and causing There was a problem that unevenness occurred in the toner layer.

Therefore, an object of the present invention is to provide a one-component developing device that eliminates the drawbacks of the prior art described above and can stably obtain a toner layer on a developing sleeve over a long period of time.

Means for Solving the Problems The present invention provides a developer carrier facing an electrostatic latent image carrier;
A means for supplying a developer onto the developer carrier, and a toner amount regulating member that presses the developer carrier, the toner amount regulating member forming a thin layer of developer on the developer carrier. In a one-component developing device in which a charge is applied at the same time as the developer formed in the thin layer is applied to an electrostatic latent image on an electrostatic latent image carrier to make it visible, the toner amount regulating member has tensile strength. Proof strength 10kgf/IM1 at 20kgf/mm2 or more
It consists of a support made of the above spring material and a soft elastic member provided at a contact portion of the support with the developer carrier, and the soft elastic member has a side surface on the toner inflow side and the developer carrier. It is characterized by having a shape such that the toner inflow angle θS in the initial state with respect to the surface satisfies at least the following formula (where θS is 1 to the side surface on the toner inflow side of the soft elastic member). (r is the radius of the developer carrier, and t is the thickness of the soft elastic member). The width LR of the member is the initial contact width of the developer carrier, fl
When N is used, it is preferable that at least the following formula is satisfied.

1/2. flN≦[R≦4ΩN In a preferred embodiment of the one-component developing device of the present invention,
The soft elastic member has a surface energy of 30 dynes/
It is preferable to use a rubber agent having a hardness of 30' to 70' and a hardness of 30' to 70'.

In the present invention, the toner inflow angle θS in the initial state between the side surface of the soft elastic member on the toner inflow side and the surface of the developer carrier is defined as the toner inflow angle θS in the initial state between the side surface of the soft elastic member 12 in the initial state and the surface of the developer carrier. It means the angle formed by the tangent at the point of contact with the semiconductive three-pro a in the agent carrier and the side surface of the soft elastic member. Therefore, when the wear of the soft elastic member progresses,
As the contact point between the side surface of the soft elastic member and the surface of the semiconductive sleeve shifts, the toner flow angle increases. The amount of increase θA in the toner inflow angle can be determined from the radius of the semiconductive sleeve and the wear depth a of the soft elastic member using the following equation.

Therefore, when the wear of the soft elastic member progresses, the toner inflow angle of 6 angles is θ angle=θS+θA.

By the way, as is clear from the test results shown in Figure 9 below,
Good results can be obtained if the toner inflow angle is within the range of 25°≦θtad≦90°. In the case where the thickness t and the wear depth a are equal, the following equation is obtained. Therefore, in order to achieve the intended purpose of the present invention until the soft elastic member is completely worn out, the following formula is required. It is sufficient to set θS so as to satisfy the following.

Further, in the present invention, the support of the toner amount regulating member has a tensile strength of 20 kgf/mm2 or more and a yield strength of 10 kgf.
/mm2 or more. Tensile strength is 2
When the yield strength is lower than 0 kgf/- and the proof stress is lower than 10 kgf/-, the soft elastic member attached to the spring material tends to undulate parallel to the axial direction of the sleeve, making it impossible to obtain a uniform toner layer.

action The operation of the present invention will be explained in comparison with the conventional technology.

FIG. 5 is a diagram illustrating a state in which development is performed using a conventional soft elastic member in which the contact width of the soft elastic member is limited. FIG. 5 (a) is a schematic cross-sectional view, and (b) (C) shows the stress distribution state at the initial stage, and (C) shows the stress distribution state when the soft elastic member is worn out. As is clear from this figure, at the initial stage, the stress at the toner inlet end of the soft elastic member is low (Fig. 5(b)), but in a worn state, the stress at the toner inflow end increases ( Figure 5 (C)
). Therefore, the amount of toner deposited on the sleeve is reduced,
Causes loss of copy density.

On the other hand, in the present invention, since the soft elastic member has the above-described configuration, the above-described problems can be solved. Figure 4 explains this, and the city is (a
) is a schematic cross-sectional view when developing using the soft elastic member according to the present invention, and (b) to (d) are diagrams for explaining the state of stress distribution. In the present invention, as the soft elastic member wears out, the stress distribution of the force PB received from the spring material at the contact portion between the soft elastic member and the semiconductive sleeve becomes averaged (see Fig. 4 (b). )). However, since the toner inflow side surface of the soft elastic member is set to the toner inflow angle θS in the initial state and has a toner inflow angle θ, the toner inflow side surface of the soft elastic member and the semiconductive sleeve are A stationary toner area is formed in the triangular area formed in between. When the stationary toner in this stationary toner area moves due to the rotation of the sleeve, it presses the toner inflow side with a force FT, so the force FS that lifts the soft elastic member due to the wedge action
occurs (Fig. 4(C)). Therefore, in the present invention, the stress distribution in the soft elastic member is the sum of these two forces (FIG. 4(d)), and the stress distribution at the toner inflow end decreases, making it easier for toner to enter. Therefore, even if the soft elastic member wears out, the amount of toner adhering to the developing sleeve does not decrease as in the prior art.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic diagram showing the configuration of a magnetic component developing device of the present invention. In the figure, 1 is a photoconductive drum (electrostatic latent image carrier) having a surface made of a positively charged inorganic photoreceptor, and the entire surface is uniformly charged by a charging means (not shown) and then exposed to light. be done. The surface potential at this time is, for example, ao
ov, the potential of the dorsal head is 120V. Reference numeral 3 denotes a hopper containing a magnetic one-component developer 4, and this one-component developer 4 is made of magnetic toner containing 48% by weight of magnetic particles. 5 is a magnet roll that waits for a magnetic pattern as shown in the figure and S, and is fixed to a frame (not shown). 6a has a specific resistance value of 4.2 xlO7Ω・cm
of phenolic resin is formed into a cylindrical shape with a wall thickness of 1.0 #, and its surface has a JIS 10-point average roughness of RZ = 4.3 μm.
It is a semiconductive sleeve (developer carrier) polished in the longitudinal direction so as to be rotatably supported around the magnet roll 5. 11 is a spring material using non-magnetic stainless steel 5US3043/4H material with a thickness of 0゜1M, and has a tensile strength of 95kOf/m and a yield strength of 68kgf/Ir.
Must have uA. A soft elastic member 12 made of silicone rubber having a rubber hardness of 50' is attached to the tip of the spring member by vulcanization adhesion, thereby forming a toner amount regulating member 7.

The shape of the soft elastic member 12 has a thickness of 3 as shown in FIG.
It has a trapezoidal shape with a base length of 5m, a top side of 2mm, and the bottom side is the surface to be bonded with h0 sulfuric acid to the spring material 11, and the top side is in contact with the semiconductive sleeve 6a. The hypotenuse part is oriented in the l·ner inflow direction, and when the soft elastic member is pressed against the semiconductive sleeve, the angle O3 between the hypotenuse part and the tangent to the semiconductive sleeve is 48°. The angle OR between the hypotenuse and the base is set to 45°. Further, the spring material 11 has a soft elastic member 12 attached to the semiconductive sleeve 6a with a diameter of 100! ? /c
The deflection angle θb of the spring material is set to 80° so that it faces 145° backward from the reference line (○°) connecting the developing position and the center of the magnet roll with a force of m. There is.

The amount of toner adhesion regulated by the toner amount regulating member constituted by the spring material 11 and the soft elastic member 12 was 1°2jQlc dust per unit surface area of the semiconductive sleeve.

The two-component developing device having the above structure is equipped with its semiconductive sleeve 6.
The toner on the semiconductive sleeve did not come into contact with the photoconductive drum when the semiconductive sleeve was placed in a copying machine so that the gap width between the sleeve and the photoconductive drum 1 was 2301 Im. Frequency 2.4Kll with AC power supply 8 and DC power supply 9
z, peak-to-peak voltage 2400V, DC component -20
When development was performed by applying a DC superimposed AC voltage of 0 V to the semiconductive sleeve 6a, a very clear image could be obtained.

In addition, even if the soft elastic member wears out due to long-term copy operations, the toner layer on the semiconductive sleeve will not be affected, and the semiconductive sleeve and spring material will come into direct contact. until a clear image was obtained).

Comparative Example FIGS. 6 and 7 illustrate the state of a soft elastic member in the prior art. FIG. 6 shows that when the soft elastic member 12 with a thickness of 3# attached to the spring material 11 has a width LR = 30 m that is sufficiently larger than the blade contact width, the central part of the soft elastic member 12 is semi-conductive. sex sleeve 13 and about 100
90.00 when the copy is in contact with the pressure of g/cm
The state of the toner amount regulating member and the semiconductive sleeve after about 0 sheets have been collected is shown. In this case, the width LN of the contact surface with the semiconductive sleeve is 15 m. in this case,
When the soft elastic member wears out, the width LN of the contact surface with the semiconductive sleeve increases, the effective pressing force decreases, and the amount of toner adhering to the semiconductive sleeve increases, resulting in thicker line images. Copying quality defects such as , burbling, etc. have occurred.

FIG. 7 shows a case where the width of the soft elastic member 12 attached to the spring member 11 is set to 5# in order to limit the width of contact with the semiconductive sleeve 13. As the soft elastic member wears out, the stress distribution on the contact surface changes, and the stress at the toner inflow portion increases, making it impossible for toner to enter the contact portion between the soft elastic member and the sleeve. Therefore, in the case shown in FIG. 7, the amount of toner deposited on the sleeve was reduced, causing a decrease in the density of the copy.

When the one-component developing device of the above embodiment and the developing device of the comparative example were compared, the results shown in FIG. 8 were obtained.

FIG. 8 is a graph showing the relationship between the number of copies and the amount of toner adhesion. In the figure, ○ indicates the case using the one-component developing device of the above embodiment of the present invention, △ indicates the case using the toner amount regulating member shown in FIG. 6, and the opening is the toner amount regulating member shown in FIG. 7. The case is shown below. As is clear from this figure, in the embodiment of the present invention, compared to the conventional technique, the amount of toner adhesion is always constant (q).

Next, the relationship between the six toner inflow angles and the amount of toner deposited on a worn soft elastic member corresponding to the case where 300,000 copies were made was investigated. Initial 1~Amount of appetizers 12rnr
When tested under the condition of j/ci, the results shown in FIG. 9 were obtained. In addition, in FIG. 9, the vertical division is 300.
The figure shows the toner adhesion amount at the time of wear corresponding to 0,000 copies, the horizontal axis shows the toner inflow angle of 0 sheets, and A shows the area where clear copies can be obtained. From this result, it was found that good results could be obtained if the toner inflow angle of six angles was within the range of 25°≦θT≦90′. This means that good results can be obtained when the initial toner inflow angle θS between the soft elastic member and the surface of the developer carrier has the following relationship.

Next, the toner inlet angle 6 was set to 90' to change the rubber hardness of the soft elastic member, and the amount of toner adhesion on the worn soft elastic member corresponding to the case where 300,000 copies were made was calculated. I investigated the relationship.

When a test was conducted with initial toner at an amount of 1.2 mg/CIi, the results shown in FIG. 10 were obtained. Note that the first
In Figure 0, the vertical axis shows the toner adhesion amount at the time of wear corresponding to 300,000 copies, the horizontal axis shows the rubber hardness, and A shows the area where clear copies can be obtained. 1st
As is clear from Figure 0, it has been found that good results can be obtained in a rubber hardness range of 30'' to 70° (I).

Furthermore, when we investigated the relationship between the width of the soft elastic member and the contact width of 9N between the soft elastic member and the phenomenon sleeve in the initial state, we found that the worn soft elastic member corresponds to the case where 300,000 copies were made. It was found that there is a relationship shown in FIG. 11 between the contact width to be opened and the amount of toner adhesion. In FIG. 11, the vertical axis shows the amount of toner adhesion at the time of final wear corresponding to 300,000 copies, and the horizontal axis shows the final contact width IR with the rubber semiconductive sleeve.
Further, A indicates an area where a clear copy can be made. From this result, it was found that a stable amount of toner adhesion can always be obtained by setting the bottom width of the soft elastic member within the range of the following formula.

1/2uN≦LR≦4. Qllll (In the formula, LR is the width 1 of the soft elastic member. QN is the initial contact width of the developer carrier.) FIG. 12 shows another embodiment of the present invention, in which non-magnetic toner is used. This is a schematic diagram of an example of a component expression @ device.

In this device, a non-magnetic one-component developer 4 is placed in a hopper 3.
The developer 4 is supplied to the developer carrier 14 by a supply roll 13 that rotates in the direction of the arrow at the same circumferential speed as the developer carrier 14.

A toner amount regulating member made of a spring member 11 and a soft elastic member 12 having the shape described in the above embodiment is provided on the surface of the developer carrier 14 so as to be in contact with it under a predetermined pressure. The one-component developer 4 supplied to the developer carrier 14 is conveyed to the position of the toner amount regulating member by the rotation of the developer carrier, and is formed into a predetermined uniform thin layer and is given a predetermined electric charge. Rear, position facing the semiconductive drum 1 (development area)
sent to. An alternating voltage is applied to the developer carrier by a DC power source 9 and an AC high voltage electric current [8], and the developer is semiconductive due to the alternating electric field generated in the gap between the semiconductive drum 1 and the developer carrier 14. The electrostatic latent image 2 is developed. Note that 15 is a sealing member.

FIG. 13 shows another embodiment of the soft elastic member. In this example, the side surface of the soft elastic member 12 on the toner inflow side has an arcuately inclined shape.

Effects of the Invention Since the one-component developing device of the present invention is equipped with a toner amount regulating member made of a soft elastic member having a predetermined shape and a spring material as described above, wear of the soft elastic member progresses. Also, the developer can always be stably attached to the semiconductive sleeve, and copying operations can be performed with a constant amount of toner applied over a long period of time. therefore,
Copy images of good quality can be obtained for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 is a schematic diagram of an embodiment of the present invention.
An explanatory diagram for explaining the shape of the soft elastic member used in the embodiment of the present invention, FIG. 3 is an explanatory diagram for explaining the toner inflow angle in the initial state, and FIG. 4 is a stress distribution state for explaining the present invention in detail. FIG. 5 is an explanatory diagram showing the state of stress distribution in the conventional technique for explaining the present invention in detail, and FIG.
7 and 7 are explanatory diagrams explaining the shape of the soft elastic member in a comparative example, FIG. 8 is a graph explaining the effect of the embodiment of the present invention, and FIG. 9 is a graph showing the toner inflow angle and the amount of toner attached. FIG. 10 is a graph showing the relationship between rubber hardness and toner adhesion amount. FIG. 11 is a graph showing the relationship between soft elastic member contact width and toner adhesion amount. FIG. 12 is a graph showing the relationship between rubber hardness and toner adhesion amount. FIG. 13 is an explanatory diagram illustrating the shape of another example of the soft elastic member used in the present invention, and FIGS. 14 and 15 are schematic diagrams of a conventional one-component developing device. is. 1... Semi-conductive drum, 2... Electrostatic latent image, 3...
Hopper, 4...-component developer, 5... Magnet roll, 6... Developing sleeve, 6a... Semi-conductive sleeve, 7... Toner amount regulating member, 8... AC high voltage power supply , 9... DC power supply, 11... Spring material, 12...
- Soft elastic member, 13... Supply roll, 14... Developer carrier, 15... Seal member. Patent applicant Fuji Xerox Co., Ltd. Agent
Patent Attorney Tsuyoshi AsabeFigure 5Figure 6Figure 7Figure 8Figure 9Figure 10Figure 12

Claims (2)

[Claims] (1) A developer carrier that faces the electrostatic latent image holder, a means for supplying developer onto the developer carrier, and a toner amount regulating member that presses the developer carrier, and A thin layer of developer is formed on the developer carrier by the toner amount regulating member, and a charge is applied to the developer, and the developer formed in the thin layer is transferred to the electrostatic latent image on the electrostatic latent image carrier. In a one-component developing device that visualizes by adhesion, the toner amount regulating member has a tensile strength of 20 kgf/mm^2 or more and a yield strength of 10 kgf/mm^2.
consisting of a support made of two or more spring materials, and a soft elastic member provided at a contact portion of the support with the developer carrier,
The soft elastic member is characterized in that it has a shape such that an initial toner inflow angle θs formed between the toner inflow side side surface and the surface of the developer carrier satisfies at least the following formula. One-component developing device. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, θs is the initial toner inflow angle between the toner inflow side of the soft elastic member and the surface of the developer carrier, r is the radius of the developer carrier, t represents the thickness of the soft elastic member) (2) The one-component developing device according to claim 1, wherein the width of the soft elastic member is within a range that satisfies at least the following formula. 1/2lN≦LR≦4lN (wherein, LR represents the width of the soft elastic member, and lN represents the initial contact width of the developer carrier)