JPH0943973A - Electrostatic latent image developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize a toner layer entirely in the width direction which is formed on a surface of a developer applying means, by pressing against one surface of a blade toward the direction that makes pressing contact with a surface of the developer applying means, providing a mounting part corresponding to the widthwise length of a blade being provided, and the other surface of the blade being mounted on the mounting part. SOLUTION: A restricting means 22 is equipped with a blade 50 comprizing a rigid member one side face of which is brought into hitting contact with a surface of a developer applying means 16 and a mounting part 512 corresponding to the widthwise length of the blade 50, and further equipped with an elastically energizing means 51 which presses against the one side face of the blade 50 toward the direction that makes pressing contact with the surface of the developer applying means 16 with the other face of the blade 50 mounted on the mounting part 512. The one side face of the blade 50 mounted on the elastically energizing means 51 is caused to act on a developper held on the surface of the developer applying means 16 by the elastically energizing means 51 with pressing force uniformized entirely in the width direction. Accordingly, a developer layer formed on the developer applying means 16 can be uniformized entirely in the width direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing device used for developing an electrostatic latent image into a toner image in an image forming machine such as an electrostatic copying machine or a laser printer, and more specifically, The present invention relates to an electrostatic latent image developing apparatus having a developer application unit that holds a developer on the surface and conveys the developer to a development area, and a regulation unit that regulates the amount of the developer retained on the surface of the developer application unit. .

[0002]

2. Description of the Related Art As is well known, in order to develop an electrostatic latent image into a toner image in an image forming machine, a developer applying means comprising a roller or an endless belt which is rotationally driven in a predetermined direction is provided. The electrostatic latent image developing device has been widely put into practical use. When the developer applying unit is driven to rotate in a predetermined direction, the developer holding region, the developer amount regulating region, and the developing region can be sequentially moved. In the developer holding area, the developer supplied by an appropriate mode is held on the surface of the developer applying means. In the developer amount regulation area, the regulation device acts on the developer retained on the surface of the developer applying unit to regulate the developer retained on the surface of the developer applying unit to a required amount. In the developing area, a developer is applied to the surface of an electrostatic latent image bearing member such as a rotating drum having an electrostatic photoconductor on the peripheral surface, and the electrostatic latent image formed on the surface of the electrostatic latent image bearing member is developed. The latent image is developed into a toner image. In order to achieve good development, the amount of developer retained on the surface of the developer applying unit is appropriately regulated by the regulating unit so that the amount of developer retained on the surface of the developer applying unit is a required amount. In addition, it is important to make it sufficiently uniform in the width direction.

Japanese Patent Publication No. 63-16736 discloses an electrostatic latent image developing device having a regulating means having a blade made of a rubber elastic body made of synthetic rubber such as urethane rubber and silicon rubber. The rubber elastic body constituting the developer regulating means has one surface or the leading edge thereof pressed against the surface of the developer applying means to regulate the amount of toner as the developer held on the surface of the developer applying means to a considerably small amount. Then, a thin layer of the developer is formed on the surface of the developer applying means. Further, the blade of the developer regulating means has a thickness of 0.1 to
Those made of 0.2 mm thin stainless steel plates for springs have also been put into practical use.

[0004]

However, in the developer regulating means using the elastic blade such as the rubber elastic body or the stainless thin plate, the both ends of the elastic blade have low rigidity and the regulating force is inferior to the central portion. Therefore, the toner layer formed on the surface of the developer applying means becomes thicker at both ends than at the center,
According to experiments conducted by the present inventors, when a urethane blade is used, the toner layers at both ends are 3.5 to 7.0 μm from the center.
It turns out that it will become thicker. As described above, when the elastic blade is used, it is difficult to make the toner layer formed on the surface of the developer applying unit have a uniform thickness in the entire width direction,
Therefore, there is a problem in that it is difficult to obtain a uniform image, and the elastic blade is not always satisfactory in terms of low wear resistance and long life.

In order to solve the above problems of the elastic blade, the applicant of the present invention has disclosed an invention in which the blade constituting the developer regulating means is formed of a rigid member such as glass.
Proposed as No. 36277. By forming the blade from plate glass, the amount of developer retained on the surface of the developer applying unit can be uniformly regulated in the width direction, abrasion resistance is improved, and toner fusion is also achieved. It was also prevented, and the life was extended. However, it has been found that the precision of the supporting means for supporting the blade formed by the plate glass affects the developer amount regulation performance. That is, as a general method of supporting the plate glass, a method of adhering the plate glass to a supporting member which is a rigid body made of metal can be considered. However, the plane accuracy of the adhesive surface of the support member becomes quite important, and if the adhesive surface of the support member is distorted, the plate glass is also attached along the adhesive surface of the support member, resulting in impaired flatness of the blade. Will end up. It is easy to set the flatness of the plate glass itself to, for example, 0.01 or less, but in order to process the surface of the metal supporting member with high accuracy, the processing cost increases and the cost increases.

Therefore, the applicant of the present invention has proposed a static latent image developing device provided with a relatively inexpensive supporting means capable of maintaining the surface accuracy of a blade made of a rigid member which constitutes the developer regulating means. Proposed as No. 6-155610.
However, this proposal uses a plurality of coil springs as the elastic biasing means for pressing one surface of the blade in the direction of pressing against the surface of the developer applying means. The toner layer formed on the surface of the developer applying unit may not always be uniform due to the influence of the concentrated load due to the contact of the toner particles, and the toner layer may not be uniform in the entire width direction. Not a thing.

The present invention has been made in view of the above facts, and its main technical problem is to provide an electrostatic latent image capable of making the toner layer formed on the surface of the developer applying means uniform in the entire width direction. An object is to provide an image developing device.

[0008]

In order to solve the above technical problems, according to the present invention, a developer housing and a developer holding area disposed in the developer housing for holding a developer on the surface thereof are provided. A developer applying means for conveying the held developer to the developing area and applying it to the electrostatic latent image, and the developer applying means in the developer control area located between the developer holding area and the developing area. In the electrostatic latent image developing device, the regulating means for regulating the amount of the developer retained on the surface of the developing means is a blade made of a rigid member, one surface of which is pressed against the surface of the developing agent applying means. An elastic urging means having a mounting portion corresponding to the widthwise length of the blade, mounting the other surface of the blade on the mounting portion, and pressing one surface of the blade in a direction in which it is pressed against the surface of the developer applying means. And having electrostatic Image developing apparatus is provided.

Further, according to the present invention, there is provided an electrostatic latent image developing device in which the elastic biasing means is constituted by a leaf spring.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electrostatic latent image developing device constituted according to the present invention will be described below in more detail with reference to the accompanying drawings.

FIG. 1 shows an image generator equipped with an electrostatic latent image developing device constructed according to the present invention. The illustrated image generator includes a rotary drum 1 as an image carrier having a photosensitive layer on its peripheral surface. The rotary drum 1 is rotatably mounted in a machine body housing (not shown) by a rotary shaft 2. Around the rotating drum 1 which is rotated in the direction indicated by the arrow 3, a charging corona discharger 4 for sequentially charging the photosensitive layer of the rotating drum 1 to a specific polarity in the direction of rotation, and the charging corona discharger. A laser optical section 5 as an exposing means for forming an electrostatic latent image on the photosensitive layer of the rotary drum 1 which is charged with a specific polarity by an electrostatic latent image formed by the laser beam emitted from the optical section 5. An electrostatic latent image developing device 6 for developing a toner image, a transfer corona discharger 7, a peeling corona discharger 8, a cleaning device 9, and a charge eliminating lamp 10 are provided.

The developing device 6 will be described with reference to FIGS. 1 to 4. The developing device 6 is provided with a developing housing 12 which can be made of synthetic resin. The developing housing 12 has a bottom wall 13 and front and rear side walls 14 and 15 which stand upright from both ends of the bottom wall 13 (see FIG. 3). And FIG. 4). In the developing housing 12 configured as above, a developer applying unit 16, a supplying unit 18, an agitating unit 20, and a regulating unit 22 are arranged. Further, although not shown, a toner cartridge containing toner is mounted on the developing housing 12.

The developer applying means 16 is a rotary shaft 24 rotatably mounted between both side walls of the developing housing 12.
And a roller 26 fixed to the rotary shaft 24, and a collar member 27 rotatably mounted on the rotary shaft 24 on both sides of the roller 26. The rotating shaft 24 can be formed of a suitable metal material such as stainless steel. The roller 26 is made of a relatively soft and conductive material, for example, a conductive solid rubber such as urethane rubber. The Asker C hardness of the roller 26 is about 60 to 85, particularly preferably about 67 to 80, and the volume resistance of the roller 26 is 10 ^{6 to} 10 ⁹ Ω.
-It is preferable that it is about cm. The collar member 27
Is made of an appropriate synthetic resin, and its outer diameter is slightly smaller than the outer diameter of the roller 26. In the developer applying unit 16 configured as described above, the roller 26 and the color member 27 are exposed through the opening formed in the developing housing 12, and are positioned to face the rotary drum 1. By bringing the peripheral surface of the collar member 27 into contact with the peripheral surface of the rotary drum 1, the roller 26 is positioned with respect to the rotary drum 1 as required. Since the outer diameter of the roller 26 is formed to be slightly larger than the outer diameter of the collar 27, the peripheral surface of the roller 26 is brought into pressure contact with the peripheral surface of the rotary drum 1, and the peripheral surface of the roller 26 is slightly elastic in the pressure contact area. It is compressed. The difference between the outer diameter of the roller 26 and the outer diameter of the collar 27, that is, the amount of compression of the roller 26 is
Although it varies somewhat depending on the outer diameter of 6 or the like, it is generally set to about 0.05 to 0.15 mm. The rotary shaft 24 of the developer applying unit 16 configured as described above is continuously driven to rotate in the direction shown by an arrow 28 in FIG. The rotation of the rotary shaft 24 causes the roller 26 to rotate.
Is also continuously rotated in the direction indicated by the arrow 28, and the peripheral surface of the roller 26 has a developer holding region 30 and a developer regulating region 32.
And the developing area 34 is sequentially conveyed.

The supply means 18 includes a rotary shaft 36 rotatably mounted between both side walls of the developing housing 12.
An auxiliary roller 38 fixed to the rotating shaft 36 is included. The auxiliary roller 38 is preferably made of foam such as foam silicon or foam urethane. The auxiliary roller 38 is pressed against the roller 26 of the developer applying unit 16. The hardness of the foam forming the auxiliary roller 38 is considerably smaller than the hardness of the roller 26 (for example, the Asker C hardness is about 35), and the auxiliary roller 38 is replaced by the roller 26.
It is desirable that the auxiliary roller 38 be elastically compressed by about 0.15 to 0.25 mm in the pressure contact region by being pressed against. The auxiliary roller 38 is continuously driven to rotate in the direction shown by an arrow 39 in FIG. The stirring means 20 includes a rotating shaft 40 rotatably mounted between both side walls of the developing housing 12, and a stirring member 42 fixed to the rotating shaft 40.
1, and is continuously driven to rotate in the direction indicated by arrow 44 in FIG.

Driving means for driving the developer applying means 16, the supplying means 18 and the stirring means 20 will be described mainly with reference to FIG. Rotating shaft 2 of developer applying means 16
4, the rotary shaft 36 of the supply means 18 and the rotary shaft 40 of the stirring means 20 each penetrate through the rear wall 15 of the developing housing 12 and project rearward, and at the rear end of each rotary shaft 24. A drive gear 45, a drive gear 46 and a drive gear 47 are mounted respectively. Drive gear 46 and drive gear 4
7 mesh with each other. The drive gear 45 and the drive gear 46 are in mesh with an intermediate gear 49 mounted on a short shaft 48 rotatably supported by the developing housing 12. The gear mechanism configured as described above is transmission-coupled to a drive source such as an electric motor via a power transmission mechanism (not shown).

Next, the regulating means 22 will be described. The regulating means 22 includes a blade 50 made of a rigid member that is pressed against the peripheral surface of the roller 26 of the developer applying means 16, and an elastic biasing force that presses one side of the blade 50 in the direction of pressing against the peripheral surface of the roller 26. And means 51.

At least one surface (that is, the surface pressed against the peripheral surface of the roller 26) of the blade 50 made of the rigid member is along the peripheral surface of the roller 26 in the width direction (direction perpendicular to the paper surface in FIG. 1). It is composed of a plate-like member that is a flat surface that extends. The surface roughness of at least a region of the one surface of the blade 50 that is pressed against the peripheral surface of the roller 26 is sufficiently small, and the center line average roughness Ra defined in JIS B 0601 is 6.00 or less, particularly 0.2.
It is preferably 0 or less, and particularly preferably 0.02 or less. If the surface roughness of the one side of the blade 50 becomes excessive, the thin layer surface of the developer formed on the peripheral surface of the roller 26 of the developer applying means 16 is not sufficiently flattened and becomes uneven. Tend to end up. Therefore, as a suitable rigid material having a sufficiently small surface roughness and high hardness and abrasion resistance even though the blade 50 can be formed at a relatively low cost, a commercially available plate glass is used. Can be mentioned. The plate glass may have a thickness of about 3 mm.
If it is desired to apply the required voltage to the blade 50 to control the charging characteristics of the toner, a conductive coating can be applied to one side of the plate glass. As the plate glass having a conductive coating on one surface, a plate glass commercially available under the trade name "Nesa glass" can be conveniently used. Instead of the plate glass, the blade 50 can be made of a rigid member made of an appropriate metal plate such as stainless steel.
In order to sufficiently reduce the surface roughness of one surface of the metal plate forming the blade 50, one surface of the metal plate may be subjected to an appropriate surface treatment, if necessary. If desired, the blade 46 may be formed of a laminated body of a plate glass and a metal plate, and one surface of the blade 46 that is brought into pressure contact with the roller 26 of the developer applying unit 16 may be defined by the exposed surface of the plate glass.

The elastic biasing means 51 has a leaf spring 511 for mounting the blade 50. This leaf spring 51
1 is composed of a stainless steel thin plate for a spring, and has a mounting portion 512 having a length substantially the same as that of the blade 50 corresponding to the width direction width of the blade 50 at the lower end portion. The surface is attached by a fixing means such as an adhesive. The upper end of the leaf spring 511 is mounted on a rotary shaft 513 rotatably mounted between the both side walls 14 and 15 of the developing housing 12 via a mounting bracket 514.
Rotating shaft 5 which can be composed of stainless steel rod
The front end of 13 is projected forward beyond the front side wall 14 of the developing housing 12, and a connecting member 515 is fixed to the front end of the projection. On the other hand, an L-shaped bracket 516 is provided on the front surface of the front side wall 14 of the developing housing 12.
Is fixed, and a screw hole is formed in the support portion of the bracket 516. A screw rod 517 is screwed into the screw hole of the bracket 516, and a lock nut 518 is screwed into the screw rod 517. A tension spring 518 is stretched between the tip of the screw rod 517 and the free end of the connecting member 515. The tension spring 519 elastically biases the rotary shaft 514 clockwise in FIG. 1, and thus the lower end of the leaf spring 511 having the upper end attached to the rotary shaft 514, that is, the contact portion 512.
The blade 50 mounted on is pressed against the roller 26 side of the developer applying unit 16. Therefore, one side of the blade 46 is pressed against the peripheral surface of the roller 26.

The electrostatic latent image developing device according to the illustrated embodiment is constructed as described above, and its operation will be described below. When the operation of the electrostatic latent image developing device is started, the roller 26 of the developer applying means 16 and the auxiliary roller 3 of the supplying means 18 are started.
8 and the stirring means 20 are rotationally driven in the direction indicated by the arrow via the power transmission mechanism and the drive gears 45, 46 and 47 by the power of a drive source (not shown). The roller 26 of the developer applying means 16 is continuously driven to rotate in the direction shown by the arrow 28, and the supplying means 18 is provided in the developer holding area 30.
Acts on the roller 26, the developer held on the peripheral surface of the roller 26 until then is separated from the roller 26, and the developer is newly supplied to the peripheral surface of the roller 26.
In the developer regulation area 32, the blade 50 of the regulation means 22 acts on the developer retained on the peripheral surface of the roller 26 to regulate the developer retained on the peripheral surface of the roller 26 to a required amount. Form a thin layer. Also, the blade 50
By the action of, the toner constituting the developer is triboelectrically charged to a predetermined polarity, for example, positive polarity.
In the developer regulating action of the blade 50, the blade 50 causes the leaf spring 511 that constitutes the elastic biasing means 51.
Since the blade 50 is mounted on the mounting portion 512 of the roller 50, the one surface of the blade 50 mounted on the plate spring 511 becomes the toner held on the peripheral surface of the roller 26 with a uniform pressing force in the entire width direction by the spring force of the plate spring 511. It works. Therefore, the toner layer formed on the surface of the roller 26 of the developer applying unit 16 can be made uniform. Next, the developing area 34
In the above, a developer is applied to the electrostatic latent image on the electrostatic photoconductor provided on the peripheral surface of the rotary drum 1, and the electrostatic latent image is developed into a toner image. For example, the electrostatic latent image is + 700V
It has a non-image area charged to a certain degree and an image area charged to about +120 V, and toner is attached to the image area (so-called reversal development). The rotary drum 1 is continuously driven to rotate in the direction indicated by the arrow 3 in FIG. 1, so that in the developing zone 34, the peripheral surface of the rotary drum 1 and the peripheral surface of the roller 26 of the developer applying means 16 move in the same direction. Be punished. Moving speed V of the peripheral surface of the roller 26
2 is set to be somewhat higher than the moving speed V1 of the peripheral surface of the rotary drum 1, and 1.2V1≤V2≤2.2V1 is preferable. In this case, a sufficient amount of the developer is conveyed to the developing area 34 by the roller 26, and the peripheral surface of the roller 26 is rubbed against the peripheral surface of the rotating drum 1 to once adhere to the non-image portion of the electrostatic latent image. The formed toner is appropriately peeled off, and thus a good toner image having an appropriate development density and no fog can be obtained. As the developer, the volume average particle size (Vol. 50%: the toner having the volume average particle size or less and the toner having the volume average particle size or more have the same volume) is about 8.0 to 12.0 μm, and the volume resistance is A developer consisting only of toner having a resistance of 10 ⁸ Ω · cm or more is preferably used.

Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the illustrated embodiment. For example, the upper end portion of the leaf spring 511 is provided on both side walls of the developing housing 12. Although an example is shown in which the rotary shaft 513 rotatably mounted between 14 and 15 is mounted via the mounting bracket 514, the upper end of the leaf spring 511 is mounted on the mounting bracket 51.
4 may be attached to the developing housing 12 and various modifications can be made within the scope of the present invention.

[0021]

The electrostatic latent image developing device according to the present invention is constructed as described above, and the regulating means for regulating the amount of the developer held on the surface of the developer applying means is provided on the surface of the developer applying means. A blade made of a rigid member, one surface of which is pressed against, and a mounting portion corresponding to the widthwise length of the blade, and the other surface of the blade is mounted on the mounting portion, and one surface of the blade is the surface of the developer applying means. Since the elastic urging means presses the surface of the developer applying means with a uniform pressing force in the entire width direction by the elastic urging means. Is made to act on the developer held in the. Therefore, the developer layer formed on the surface of the developer applying unit can be made uniform in the entire width direction.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram of an image generator equipped with an electrostatic latent image developing device according to an embodiment configured according to the present invention.

FIG. 2 is a perspective view showing a main part of the electrostatic latent image developing device shown in FIG.

FIG. 3 is a partial perspective view showing a front surface portion of a developing housing in the electrostatic latent image developing device shown in FIG.

4 is a partial perspective view showing a rear surface portion of a developing housing in the electrostatic latent image developing device shown in FIG.

[Explanation of symbols]

 1: Rotating drum 4: Charging corona discharger 5: Laser optical part 6: Electrostatic latent image developing device 7: Transfer corona discharger 8: Peeling corona discharger 9: Cleaning device 10: Static elimination lamp 12: Development housing 16: Developer Applying Means 18: Supplying Means 20: Stirring Means 22: Regulation Means 26: Rollers of Developer Applying Means 30: Developer Retaining Areas 32: Developer Regulating Areas 34: Developing Areas 38: Auxiliary Rollers of Supplying Means 45 : Drive gear 46: Drive gear 47: Drive gear 49: Intermediate gear 50: Blade 51: Elastic biasing means 511: Leaf spring 512: Mounting portion 513: Rotating shaft 514: Mounting bracket 515: Connecting member 516: L-shaped bracket 517: Screw rod 518: Stop nut 519: Tension spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoyuki Ishida 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Industrial Co., Ltd. (72) Takahisa Nakaue 1-2-2 Tamatsukuri, Chuo-ku, Osaka Within Mita Engineering Co., Ltd.

Claims (2)

[Claims] 1. A developing housing, and a developer for holding a developer on a surface in a developer holding area provided in the developing housing and conveying the held developer to the developing area to apply it to an electrostatic latent image. Electrostatic comprising a developer applying means and a restricting means for restricting the amount of the developer held on the surface of the developer applying means in a developer controlling area located between the developer holding area and the developing area. In the latent image developing device, the regulating means includes a blade made of a rigid member, one surface of which is pressed against the surface of the developer applying means, and a mounting portion corresponding to the widthwise length of the blade. An electrostatic latent image developing device, comprising: an elastic urging means for mounting the other surface of the blade and pressing one surface of the blade in a direction in which the blade is pressed against the surface of the developer applying means. 2. The electrostatic latent image developing device according to claim 1, wherein the elastic biasing means is constituted by a leaf spring.