JPH063966A - One-component developing device - Google Patents

Abstract

PURPOSE:To provide the one-component developing device with which the image having a uniform medium contrast is obtainable and the density of a developed image is sufficiently obtainable even if the developer of a developer carrying member is consumed in a large amt. like the solid black image. CONSTITUTION:This one-component developing device has the developer carrying member 1 which is disposed to face an electrostatic latent image carrying member and ejects the one-component developer T housed in a hopper to a development region and a developer regulating member 2 which forms the thin layer of the developer by pressing a soft elastic member 22 fixed at one end of a spring plate member 21 via the developer to the developer carrying member 1 and forming a nipple surface 22a. The developing device is so constituted that the angle theta formed by the developer inflow side front end face 22b of the soft elastic member 22 and the nip surface 22a satisfies the relation 105 deg.<=theta<=165 deg. and that the end of the developer regulating member 2 serving as a fulcrum from the end of the spring plate member 21 fixed with the soft elastic member 22 exists on the upstream side of the rotating direction of the developer carrying member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component developing device for developing an electrostatic latent image using a one-component developer, and more particularly to a one-component developing device for performing good development without density unevenness. Regarding improvement.

[0002]

2. Description of the Related Art As a developing device for developing an electrostatic latent image formed on a latent image carrier to form a visible image, various types have been conventionally proposed according to the type of developer used. There is. Among these, as a developing device using a one-component developer consisting of only toner, for example, those shown in FIGS. 10 to 13 are known.

FIG. 10 shows a one-component developing device which uses magnetic toner as a developer. A hopper a for containing the magnetic toner T and a magnet b2 having a plurality of magnetic poles in a rotatable cylindrical sleeve b1. Is fixedly arranged, and the developer carrier b for adsorbing the magnetic toner T on the sleeve b1 by the magnetic force.
And the soft elastic member c2 that is in contact with the developer carrying member b and the end (fulcrum side end) that supports the soft elastic member c2 are more upstream than the end to which the soft elastic member c2 is fixed. It is composed of a developer regulating member c for thinning the magnetic toner T conveyed by the positioned spring plate member c1. The developer carrier b is generally a developing roll.

FIG. 11 shows a one-component developing device that uses magnetic toner as a developer. A hopper a for containing the magnetic toner T and a magnet b2 having a plurality of magnetic poles in a rotatable cylindrical sleeve b1. Is fixedly arranged, and the developer carrier b for adsorbing the magnetic toner T on the sleeve b1 by the magnetic force.
And the magnetic toner carried by the spring plate member c1 located downstream of the fulcrum-side end of the soft-elastic member c2 that is in contact with the developer carrier b in the rotation direction of the developer carrier. And a developer regulating member c for thinning T.

FIG. 12 shows a one-component developing device using non-magnetic toner. In this apparatus, as compared with the developing apparatus shown in FIG. 10, it is impossible to attract the toner T onto the sleeve b1 by the magnetic force. Therefore, the developer supply roll d is disposed adjacent to the developer carrier b. The non-magnetic toner T in the hopper a is pressed against the developer carrying member b by the supply roll d to forcibly adhere thereto.

FIG. 13 shows a one-component developing device using non-magnetic toner. In this device, as compared with the developing device shown in FIG. 11, it is impossible to attract the toner T onto the sleeve b1 by the magnetic force, so that the developer supply roll d is disposed adjacent to the developer carrier b. The non-magnetic toner T in the hopper a is pressed against the developer carrying member b by the supply roll d to forcibly adhere thereto.

[0007]

10 and 12, that is, the base end (fulcrum side end) of the spring plate member c1 is arranged upstream of the nip position in the developer inflow direction. Further, in the one-component developing device, since the wedge angle of the wedge-shaped region before the nip between the developer regulating member c and the developer carrying member b is small, the force by which the developer T pushes up the developer regulating member c becomes large. Therefore, in order to form a thin layer of toner, the spring constant of the spring plate member c1 must be increased. It was not possible to obtain a uniform layer thickness of the developer in the horizontal direction, and in particular, uneven density of a halftone image may occur.

Further, in the one-component developing device constructed as shown in FIGS. 11 and 13, that is, in which the base end of the spring plate member c1 is arranged on the downstream side of the nip position in the developer inflow direction, the developer regulation is performed. Since the force for pushing up the member c is small, the developer controlling member c can thin the developer T to a very stable predetermined layer thickness, and the developer carrying member b
The electrostatic latent image f is developed by causing the developer T to fly from the electrostatic latent image carrier e to the electrostatic latent image carrier e, but when a large amount of the developer on the developer latent image carrier is consumed like solid black. Since a large amount of developer is supplied to the developer carrying member b, the charge amount of the developer charged through the nip between the developer regulating member c and the developer carrying member b becomes insufficient. However, there is a problem that the density of the developed image may not be sufficiently obtained. That is, the developer charged through the nip is
Although it reaches the upstream side of the soft elastic member c2 after making a round of the developer carrier b, the developer hitting the soft elastic member c2 escapes laterally or outward of the soft elastic member c2, and the charge amount is There is a problem that the increased developer cannot be stored in the area before the nip.

For this reason, in the area before the nip between the developer regulating member c and the developer carrying member b, the developer whose charge amount has increased by passing through the nip between the developer regulating member c and the developer carrying member b in advance. Storage is required.

The present invention has been made in view of the above problems, and an object of the present invention is to obtain a uniform halftone image and to increase the amount of the developer on the developer carrier such as black solid. It is an object of the present invention to provide a one-component developing device capable of sufficiently obtaining the density of a developed image even when it is consumed.

[0011]

In order to achieve the above object, a one-component developing device of the present invention is configured so that a one-component developer, which is disposed opposite to an electrostatic latent image bearing member and accommodated in a hopper, is transferred to a developing area. Development for forming a thin layer of developer by pressing a developer carrier to be carried out and a soft elastic member fixed to one end of a spring plate member against the developer carrier via the developer to form a nip surface In a one-component developing device including a developer regulating member, an angle θ formed by the front end face of the soft elastic member on the developer inflow side and the nip face satisfies a relation of 105 ° ≦ θ ≦ 165 °, and the developer regulating member is provided. The member is arranged such that an end serving as a fulcrum is located upstream of the end of the spring plate member to which the soft elastic member is fixed in the rotation direction of the developer carrying member.

[0012]

The operation of the present invention will be described in detail with reference to FIGS.

The one-component developing device of the present invention comprises a developer carrier 1 for carrying out the one-component developer T, which is arranged in opposition to the electrostatic latent image carrier and accommodated in a hopper, to a developing area, and a spring plate member 21. And a developer regulating member 2 for forming a thin layer of developer by pressing a soft elastic member 22 fixed to one end of the developer carrier 1 onto the developer carrier 1 via the developer to form a nip surface 22a. Assuming a one-component developing device, the developer inflow side front end surface 22b of the soft elastic member 22 and the nip surface 2 are described.
The angle θ formed by 2a satisfies the relation of 105 ° ≦ θ ≦ 165 °, and the developer regulating member 2 is the soft elastic member 2
The spring plate member 21 to which 2 is fixed is arranged so that its end serving as a fulcrum is located on the upstream side in the direction of rotation of the developer carrier.

According to the present invention, as shown in FIGS. 1 and 2, the front end surface 2 of the soft elastic member 22 is caused by the inflow pressure of the developer T flowing between the developer carrier 1 and the soft elastic member 22.
A force F acts on 2b to generate a component force f that pushes up the tip of the developer regulating member 2. Therefore, the developer T more easily flows into the space between the developer carrier 1 and the soft elastic member 22, and a desired developer thin layer having no unevenness can be obtained. Further, the spring plate member 2 is provided on the upstream side of the soft elastic member 22.
1 is present, the developer after charging goes around the developer carrying member 1 and is captured in the space between the developer carrying member 1 and the spring plate member 21, and the developer regulating member 2 and the developer carrying member 2 are carried. In the area before the nip of the body 1, the developer having a large amount of charge that has passed through the nip between the developer regulating member 2 and the developer carrying body 1 can be stored in advance.

As a result, it is possible to obtain a uniform halftone image, and it is possible to obtain a sufficient density of the developed image even when a large amount of the developer on the developer carrying member is consumed such as solid black. Become.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A one-component developing device of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 3 shows a first embodiment of a one-component developing device according to the present invention. This one-component developing device uses a one-component developer T of a magnetic toner, and includes a developer carrier 1 arranged to face the electrostatic latent image carrier 4 and a tip end portion of the developer carrier 1 described above. And a developer regulating member 2 arranged so as to come into pressure contact with the developer regulating member 2, which are arranged in a hopper 3 for accommodating the developer T. In this embodiment, the electrostatic latent image carrier 4 is a photoconductor drum, and the developer carrier 1 is a developing roll.

First, in the developer carrying member 1, a plurality of magnetic poles (N ..., S ...) Having different polarities and magnetic forces are magnetized, and a magnet roll 11 fixedly supported by a casing (not shown), It is composed of a cylindrical sleeve 12 that rotates around the magnet roll 11, and the developer T is adsorbed, conveyed, and released from the sleeve 12 according to the magnetic pattern of the magnet roll 11 as the sleeve 12 rotates. It is supposed to be. AC power supply 3 for sleeve 12
1 and a DC power source 32 apply a developing bias voltage.

In this embodiment, the sleeve 1 described above is used.
2 is a phenol resin having a resistivity of 5 × 10 ⁹ Ω · cm molded into a cylindrical shape with a wall thickness of 1.0 mm, the surface of which is JIS 1
A semiconductive sleeve was used, which was polished in the longitudinal direction so that RZ = 4.3 μm in 0-point average roughness.

The hopper 3 is provided with the developer carrying member 1.
Is provided so as to cover the lateral side from below, and the stored developer T is accumulated on the back surface side of the developer carrying member 1 and is continuously applied to the surface of the sleeve 12 after passing through the developing area D. It has a structure that can supply. In this embodiment, as the developer T contained in the hopper 3, a magnetic toner containing 48% by weight of magnetic powder is used.

On the other hand, the developer regulating member 2 is, as shown in FIG. 4, a spring plate member 21 (SUS) having a thickness of 0.05 mm.
Made of 304CSP 3 / 4H: Tensile strength 95kgf / mm
² , yield strength 68 kgf / mm ² ) and this spring plate member 21
Soft elastic member 22 (made of silicone rubber: rubber hardness 50 °, thickness 1 mm) vulcanized and bonded to the tip of the spring plate member 21
1 mm thick supporting member 23 (made of non-magnetic stainless steel SUS304: tensile strength 53 kgf / mm
² , and a proof stress of 21 kgf / mm ² ).

The spring plate member 21 is evenly adhered to a supporting member 23 having a sufficiently high rigidity with a protruding length L _S = 6 mm, and the spring plate is secured by screwing the supporting member 23 having a sufficient rigidity to the holder 5. The deformation of the member 21 is prevented. Further, in the holder 5, the soft elastic member 22 is always provided with the linear pressure 20.
It is biased by the coil spring 6 to nip the sleeve 12 at gf / cm. The contact position of the developer regulating member 2 with respect to the sleeve 12 is 70 ° in the direction opposite to the rotation direction of the sleeve 12 from the position where the developer carrying member 1 and the electrostatic latent image carrying member 4 face each other.

Further, as shown in FIG. 1, the soft elastic member 22 forms an angle θ between a nip surface 22a for nipping the developer carrying member 1 through the developer T and a front end surface 22b on the developer inflow side. Has a substantially trapezoidal shape formed at 135 °, the nip surface 22a is shaped to have a width L _R = 1.0 mm, and the entire width of the surface 22a nips the sleeve 12 via the developer T. It has become.

In this embodiment, a photoconductive photosensitive drum is used as the electrostatic latent image carrier 4, and the gap width between the developer carrier 1 and the electrostatic latent image carrier 4 is 200 μm. On the other hand, the AC power source 31 is applied to the sleeve 12 of the developer carrying member 1.
And a DC power supply 32 were connected, and a DC superimposed AC voltage having a frequency of 2.4 kHz, a peak-to-peak voltage of 2400 V, and a DC component of -200 V was applied.

When a copy was taken in this state, a uniform image was obtained even in a halftone, and a recorded image without a decrease in density was obtained even if a black solid image was developed.

Next, the meaning of the angle θ formed by the nip surface 22a of the soft elastic member 22 and the front end surface 22b on the developer inflow side will be described. This angle θ affects the component force f that pushes up the tip of the developer regulating member 2 as shown in FIG. 2, and when the angle θ changes, the amount of developer attached to the sleeve 12 changes. Further, the protrusion length L of the developer regulating member 2 also affects the amount of developer attached.

FIG. 5 is a graph in which the change in the developer adhesion amount with respect to the change amount of the protrusion length L of the developer regulating member 2 is plotted with the angle θ as a parameter. Incidentally, the range of the developer adhesion amount suitable for developing the electrostatic latent image is 0.60 to 1.10.
It is mg / cm ² . In addition, in the graph of FIG.
The change amount of the protrusion length L when the developer regulating member 2 and the developer carrying member 1 are in contact with each other when the spring plate member 21 is not deformed is set to 0. Also, based on the results of FIG.
A graph of FIG. 6 shows a change in the mounting allowable error of the developer regulating member 2 with the change of the angle θ. As can be seen from the graph shown in FIG. 6, the mounting allowance of the developer regulating member 2 is 4 mm or more in the range of 105 ° ≦ θ ≦ 165 °, which proves that the developer regulating member 2 can be easily mounted. . If the mounting tolerance is 4 mm or more, the degree of freedom in design increases, and
Performance after assembly is also easy to obtain.

In the above first embodiment, the one-component developing device using the magnetic toner as the developer has been described as an example, but the present invention is applied to the one-component developing device using the non-magnetic toner. It goes without saying that the same effect can be obtained. In this case, as shown in FIG. 7, it is necessary to dispose the developer supply roll 7 adjacent to the developer carrier 1 and forcibly press the developer T onto the sleeve 12.

In the above embodiment, the soft elastic member 22 is made of silicone rubber or EPDM rubber.
In addition to these, urethane rubber, fluororubber, butadiene rubber,
Various rubber agents such as acrylic rubber and thermoplastic elastomers may be used. However, it is preferable that any material has a surface energy of 30 dyn / cm or less and a hardness of 30 to 70 °.

Further, the shape of the front end surface of the soft elastic member 22 is not limited to a flat surface, and may be a concave curved surface as shown in FIG. 8 (A) or a convex curved surface as shown in FIG. 8 (B). Same figure (A)
In the case of the shape of, the developer T easily flows into the nip surface 22a between the soft elastic member 22 and the sleeve 12, and the developer T
On the other hand, in the shape shown in FIG. 3B, the soft elastic member 22 and the sleeve 12 are likely to be uniformly pressed against each other. Even when the front end surface of the soft elastic member 22 is not a flat surface as in the modified example shown in FIG. 8, the deviation from the flat surface is about ± 0.3 mm at the maximum displacement portion (intermediate portion). The angle formed by the front end face can be judged from the average angle of the shape of the entire front end face.

Next, another structural example of the developer carrying member 1 will be described.

As shown in FIG. 9, the developer carrying member 1 is formed by coating a layer made of a semiconductive resin on a base material 1a which is a cylindrical member made of aluminum or non-magnetic stainless steel. The resin layer 1b applied on the peripheral surface of the substrate 1a is an epoxy resin containing conductive carbon and silica, and has a resistivity of 1 × 10 ² Ω · cm to 1 × 10 ⁸ Ω · cm. It is applied so that the resistance per 1 cm ² is 0.5 Ω to 10 ⁴ Ω in the thickness range of about 0.05 mm to 0.1 mm. The surface of the resin layer 1b is mechanically polished in the axial direction of the developer carrying member 1 and has a JIS 10-point average roughness of RZ = 0.8 to 2.5 μm. Flange 1c is fitted to both ends of the cylindrical substrate 1a,
The developer carrying member 1 is attached to a rotary shaft (not shown) via the flange 1c.

The base material 1a of the developer carrying member 1 has a thickness of 0.4.
mm to 1.2 mm, and the end portion in the axial direction has an outer peripheral surface of 0.1 mm to 0.1 mm in the thickness direction as shown in FIG.
The chamfer is 0.6 mm and 0.1 mm to 0.6 mm in the axial direction. Along with this, the semiconductive resin layer 1b also has an obtuse angle instead of a right angle, and therefore the end circumferential surface is less likely to be damaged during handling after the developer carrying member 1 is manufactured. That is, it becomes difficult for the base material 1a to be exposed. Therefore, even if the surface of the electrostatic latent image carrier 4 (see FIG. 7) has a pinhole and the conductive base material of the electrostatic latent image carrier 4 is exposed, the electrostatic latent image carrier is also exposed. 4 does not generate a spark discharge between the developer carrying member 1 and the factors that adversely affect the output image, such as fluctuations in the developing bias caused by the spark discharge and changes in the potential of the electrostatic latent image, are eliminated. .

The constitution of the developer carrying member 1 is not limited to the above-mentioned embodiment, and if the adhered developer T can be conveyed to the developing area D, the constitution thereof will depend on whether the toner is magnetic or non-magnetic. The design may be changed as appropriate.

The design of the developer regulating member 2 may be appropriately changed according to the desired thickness of the thin toner layer such as the attachment to the holder 5 and the tensile strength of the spring plate member 21. The design of the method for applying the pressing force for nipping the carrier 1 may be changed as appropriate. However,
From the viewpoint that a constant contact pressure is always generated between the soft elastic member 22 and the developer carrying member 1, a structure in which the holder 5 of the developer regulating member 2 is biased by the coil spring 6 is preferable.

Further, in the present invention, the soft elastic member 22 is used.
If the predetermined region L _R nips the developer carrying member 1 through the developer from the front end side where the developer flows between the member 22 and the developer carrying member 1, the nip is The entire surface does not need to nip the developer carrying member 1. However,
Considering the increase of the nip area due to wear and plastic deformation of the soft elastic member 22 over time, the displacement of the nip position, etc., it is preferable that the entire surface of the nip nips the developer carrying member 1 from the beginning.

[0037]

As described above, according to the one-component developing device of the present invention, the developer flowing between the developer carrying member and the soft elastic member pushes up the tip of the developer regulating member,
Since a uniform developer thin layer is formed by flowing between the developer carrier and the soft elastic member, a uniform halftone image can be obtained. In addition, since a large amount of charged developer is stored in the developer regulating member portion, it is necessary to obtain a sufficient density of the developed image even when a large amount of developer on the developer carrying member is consumed such as solid black. Is possible.

[Brief description of drawings]

FIG. 1 is an enlarged view showing a main part of a one-component developing device of the present invention.

FIG. 2 is an explanatory view showing an acting direction of a force acting on a soft elastic member of a developer regulating member used in the one-component developing device of the present invention.

FIG. 3 is a sectional view showing a first embodiment of the one-component developing apparatus of the present invention.

FIG. 4 is a sectional view showing a main part of a one-component developing device according to the first embodiment.

FIG. 5 is a graph in which the change in the amount of developer attached to the amount of change in the protrusion length of the developer regulating member is plotted using the front end face angle of the soft elastic member as a parameter.

FIG. 6 is a graph showing a change in an allowable mounting error of the developer regulating member with respect to a front end face angle of the soft elastic member.

FIG. 7 is a sectional view showing a second embodiment of the one-component developing apparatus of the present invention.

FIG. 8 is an enlarged sectional view of an essential part showing another example of the structure of the developer regulating member.

FIG. 9 is an enlarged partial cross-sectional view of an axial end portion of a developer carrier of the one-component developing device.

FIG. 10 is a cross-sectional view showing a conventional magnetic one-component developing device in which a fulcrum of a developer regulating member is arranged on the upstream side of a nip portion.

FIG. 11 is a cross-sectional view showing a conventional magnetic one-component developing device in which the fulcrum of the developer regulating member is arranged on the downstream side of the nip portion.

FIG. 12 is a cross-sectional view showing a conventional non-magnetic one-component developing device in which a fulcrum of a developer regulating member is arranged on the upstream side of a nip portion.

FIG. 13 is a cross-sectional view showing a conventional non-magnetic one-component developing device in which a fulcrum of a developer regulating member is arranged on the downstream side of a nip portion.

[Explanation of symbols]

1: developer carrier, 1a: base material, 1b: resin layer, 1c:
Flange, 2: developer regulating member, 3: hopper, 4: electrostatic latent image carrier, 5: holder, 6: coil spring, 7: developer supply roll, 11: magnet roll, 12: cylindrical sleeve, 21: Spring plate member, 22: soft elastic member, 2
2a: nip surface, 22b: front end surface, 23: support member, 3
1: AC power supply, 32: DC power supply, D: developing area, T: toner, a: hopper, b: developer carrier, b1: cylindrical sleeve, b2: magnet, c: developer regulating member, c1: spring Plate member, c2: soft elastic member, d: developer supply roll,
e: electrostatic latent image carrier, f: electrostatic latent image,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Inaba 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business Office (72) Inventor, Katsuhiko Ichikawa 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business In-house (72) Inventor Katsunari Higuchi 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (1)

[Claims] 1. A developer carrier for carrying out a one-component developer housed in a hopper, which is arranged to face an electrostatic latent image carrier, to a developing area, and a soft elastic member fixed to one end of a spring plate member. In a one-component developing device comprising a developer regulating member that forms a thin layer of the developer by pressing the developer bearing member through the developer to form a nip surface, the developer inflow of the soft elastic member The angle θ formed by the side front end face and the nip face satisfies the relation of 105 ° ≦ θ ≦ 165 °, and the developer regulating member serves as a fulcrum from the end of the spring plate member to which the soft elastic member is fixed. A one-component developing device, characterized in that the end portion is arranged on the upstream side in the rotation direction of the developer carrier.