JP3061887B2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used to visualize an electrostatic latent image in an electrophotographic apparatus or an electrostatic recording apparatus.

[0003]

2. Description of the Related Art In a developing device in which a thin toner layer is formed on the surface of a toner carrier (developing roller) and the electrostatic latent image is visualized (developed) by the thin toner layer, the thickness of the toner layer is regulated. Is a very important point in determining the quality of image quality.
Means for regulating the thickness of such a thin toner layer include:
Conventionally, the following means are known.

(1) A plate-like toner layer thickness regulating member is pressed against the surface of the toner carrier.

(2) A cylindrical or cylindrical toner layer thickness regulating member is pressed against the surface of the toner carrier. The method or means using the plate-like toner layer thickness regulating member of the above (1) is described in, for example, JP-B-51-36070, JP-B-63-16736, and JP-A-53-2736.
No. 3638, No. 57-165866 and the like.By pressing the end portion or abdominal surface of the plate-shaped regulating member against the toner carrier surface, a toner thin layer having a uniform thickness is formed, The particles are frictionally charged to obtain a visible image.

On the other hand, the method or means of (2) using a cylindrical or cylindrical toner layer thickness regulating member is classified into the following two methods.

(A) For example, JP-A-59-126567,
As described in JP-A-59-129880, a roller (toner layer thickness regulating member) that rotates intermittently or continuously is
The toner is pressed against the surface of the toner carrier, and the thickness of the toner layer is regulated by the nip therebetween.

(B) For example, Japanese Patent Application Laid-Open No. 1-282578,
As described in JP-A-283577, a roller (toner layer thickness regulating member) having rigidity or rubber elasticity is fixed, and is pressed against the surface of the toner carrier in this state, and a uniform and stable toner layer with a low load is applied. Get.

[0009]

However, the conventional developing devices using the above-described various toner layer thickness regulating members have the following disadvantages.

For example, in a developing device using a plate-shaped toner layer thickness regulating member as described in the above (1), the processing accuracy of the layer thickness regulating member, in particular, the warpage or undulation in the longitudinal direction may cause the toner layer to fail. This results in uniformity and insufficient triboelectric charging, leading to toner spill and deterioration of image quality. Further, the toner stays or sticks in a wedge-shaped space formed between the toner layer thickness regulating member and the toner carrier, and the toner damages the toner carrier, thereby causing white stripes or the like on an image. I was

Further, among the developing devices using the cylindrical or cylindrical toner layer thickness regulating member shown in the above (2), (a)
As described above, when the roller (toner layer thickness regulating member) is rotated, a uniform toner thin layer can be obtained stably, but the roller is rotated so as to follow the toner carrier. In addition, the toner sandwiched in a wedge-shaped space formed between the toner layer thickness regulating member and the toner carrier passes through with rotation, resulting in deterioration of image quality.

On the other hand, in the developing device to which the toner regulating method of (b) is applied, since the toner layer regulating member is always fixed, a wedge-shaped member formed between the toner layer regulating member and the toner carrier is formed. In order to form a desired thin toner layer, since the toner particles tend to stay in the space, and the subsequent toner particles try to extrude the toner particles, the toner layer thickness regulating member is loaded with the toner at a relatively high pressure. You must press against the body surface. As a result, there have been problems such as that toner adheres to the surface of the toner carrier and the surface of the regulating member, and that the force required for driving the toner carrier becomes large. Further, when the toner particles are sandwiched in a wedge-shaped space, a uniform thin toner layer is not formed, and the toner carrier is damaged, resulting in image stains,
White streaks and the like are generated, which causes the image quality to deteriorate.

SUMMARY OF THE INVENTION The present invention has been made to address such problems in the prior art, and enables a thin toner layer to be uniformly and stably formed on a toner carrier, thereby ensuring good image quality. It is an object of the present invention to provide a developing device obtained by the above.

[Configuration of the Invention]

[0015]

According to the present invention, there is provided a developing device comprising: a toner carrier; toner supply means for supplying toner to the outer peripheral surface of the toner carrier; A toner layer thickness regulating member having a substantially cylindrical shape. The toner supplied to the outer peripheral surface of the toner carrier by the toner layer thickness regulating member is thinned, and the thin toner layer is brought close to the latent image holding member. Or in contact with the developing device to visualize the electrostatic latent image held by the latent image holding body,
The toner layer thickness regulating member is rotatable when desired, and is fixed during development. And said
The developing device includes a toner cart that holds and supplies the toner.
A ridge, and when replacing the toner cartridge,
The toner layer thickness regulating member is rotated by the replacement operation.
You can make it. Further, the developing device includes a main body.
A cover.
The body layer thickness regulating member did not rotate, and opened the main body cover.
Later, when the toner layer thickness regulating member is closed again,
You can make it.

[0016]

The developing device of the present invention is provided with a mechanism that enables the substantially cylindrical toner layer thickness regulating member to be rotatable, for example, in a direction opposite to the toner carrier (developing roller) only when desired. Therefore, during development, the toner layer thickness regulating member is fixed and pressed against the toner carrier in this state, so that a thin toner layer can be uniformly and stably formed. In addition, the toner remaining or fixed in the wedge-shaped space generated between the toner layer thickness regulating member and the toner carrier can be removed by appropriately rotating the toner layer thickness regulating member, thereby causing image quality defects. Can be suppressed. Further, in the present invention, by making the toner layer thickness regulating member substantially cylindrical, the processing accuracy of the toner layer thickness regulating member is improved, and a good thin toner layer can be formed. In the present invention, it goes without saying that the substantially columnar toner layer thickness regulating member may be, for example, a cylindrical member having a hollow inside. Further, the toner layer thickness regulating member is sandwiched between the toner layer thickness regulating member and the toner carrier by rotating the toner layer thickness regulating member at a desired time as long as the toner layer thickness regulating member has a shape having at least a rotation axis without being particularly cylindrical. Toner can be eliminated.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a schematic configuration of a developing device according to one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a toner container containing, for example, a one-component toner 2. In the toner container 1, a stirrer 3 and a toner supply roller 4 are provided as toner supply means. The toner 2 is transported onto the toner carrier (developing roller) 5 by the stirrer 3 and the toner supply roller 4.

The toner carrier (developing roller) 5 is made of metal such as aluminum and stainless steel, phenol resin, acrylic resin, urethane resin, fluorine resin, polyamide resin, silicone resin, melanin resin, polystyrene resin,
A hard or soft resin such as a polyester resin or an epoxy resin, or a composite of these resins can be used, and a magnetic roller having a magnetic pole disposed therein may be used. In this embodiment, a non-magnetic (or non-magnetized) developing roller 5 having elasticity and conductivity is used. As the elastic conductive roller, a conductive rubber layer (for example, urethane rubber, silicon rubber, ethyleneprene rubber, NBR,
Conductive carbon particles, metal particles, metal fibers, etc. dispersed in chloroprene rubber, butyl rubber, etc. to provide a resistance value of 10 ¹⁰ Ωcm or less), and silicon resin, urethane Resin, fluorine resin, etc., high resistance or insulating rubber roller surface coated with conductive resin, semi-conductive rubber roller surface with microelectrodes electrically insulated from each other Etc. are preferred. Here, especially hardness 30
Conductive urethane paint is applied to the surface of a urethane rubber roller of degree (JIS-A type hardness tester), and the elastic conductive roller is adjusted so that the resistance value between the metal shaft and the coating film surface is 10 ⁶ Ωm ² or less. Using. Outer diameter of metal shaft is 8mm, outer diameter of rubber roller is 18mm, thickness of conductive urethane paint is 20μm
200200 μm.

In the vicinity of the developing roller 5, a toner layer thickness regulating member 6 constituted by a columnar member is disposed. The toner layer thickness regulating member 6 is pressed against the outer peripheral surface of the developing roller 5 by the pressing force of the spring 7.
The toner 2 carried on the outer peripheral surface of the developing roller 5 passes between the developing roller 5 and the toner layer thickness regulating member 6 to be thinned and to have a prescribed charge.

The cylindrical member used as the toner layer thickness regulating member 6 preferably has a curved surface with a radius of about 0.1 mm to 20 mm, more preferably about 0.5 mm to 10 mm. The constituent material of the toner layer thickness regulating member 6 includes metals such as aluminum and stainless steel, phenol resin, acrylic resin, urethane resin, fluorine resin, polyamide resin, silicon resin, melanin resin, polystyrene resin, polyester resin, epoxy resin and the like. Hard or soft resins, and composites thereof, or elastic bodies such as urethane rubber and silicone rubber.

A latent image holding member (photosensitive drum) 8 faces the developing roller 5 which carries the thin toner layer and rotates.
Is arranged. Then, the latent image holding member 8 on which the electrostatic latent image is formed by the exposure light 9 is brought into contact with the developing roller 5 carrying the toner latent image, so that the developer is deposited on the electrostatic latent image. Thereby, the electrostatic information recorded on the latent image holding member 8 is visualized (developed). This visible image is recorded on recording paper by the transfer device 10, for example. The toner remaining on the developing roller 5 is
The toner is collected in the toner container 1 by the recovery plate 11. In the figure, reference numeral 12 denotes a charger for applying a required electrostatic charge to the latent image holding member 8, reference numeral 13 denotes a DC power supply for supplying a required current to the toner carrier 5 and toner supply roller 4, and reference numeral 14 denotes a protection resistor.

In the above-described embodiment, the developing device to which the developing method in which the developing roller 5 is brought into contact with the latent image holding member 8 to perform the development is described as the developing method of the electrostatic latent image. A method in which the roller 5 and the latent image holding member 8 are brought into a non-contact state and the toner particles are caused to fly by a developing electric field to perform development; a method in which a DC electric field is formed between the two for development; It is possible to apply various developing methods such as a method of performing the developing. Further, as the toner 2, a toner composed of various known binder resins, coloring agents, charge control agents, waxes, anti-caking agents and the like are used.
For example, a negatively chargeable toner having a volume average particle diameter of 10 μm, comprising 92 parts by weight of a polyester resin, 4 parts by weight of a copper phthalocyanine pigment, 2 parts by weight of a low molecular weight polypropylene, 2 parts by weight of a gold-containing dye, and 0.5 part by weight of an external additive silica. Is done.

Next, referring to FIGS. 2, 3 and 4,
An operation mechanism of the toner layer thickness regulating member 6 in the developing device will be described. A gear (claw wheel) 15 is provided coaxially with the toner layer thickness regulating member 6. This gear 15
A lever (supporting member) 16 provided with an L-shaped claw 15a at the tip is disposed at a position where the lever engages with the tooth of the second member. The lever 16 is movable in the circumferential direction about the support shaft 17. In the normal state, the lever 16
The pawl 16a at the tip of the lever 16 is meshed with the teeth of the gear 15 by a spring 18 having a force to pull the gear upward. Accordingly, the gear 15 and the toner layer thickness regulating member 6 coaxial with the gear 15 are fixed, and do not follow the rotation of the developing roller 5. The toner layer thickness regulating member 6 is applied to the developing roller 5 by a spring 7 at 30 to 200 g / cm, preferably 50 to 120 g / cm.
It is pressed with a constant load within the range of cm. In this state,
Usually, development is performed.

The rotation of the toner layer thickness regulating member 6 is performed as follows. With the developing roller 5 stopped, the lever 16 is rotated counterclockwise about the support shaft 18 to release the claw 16a at the tip of the lever 16 from engagement with the gear 15, and then the lever 16 is moved obliquely downward and to the right. Press down. In this state, the lever 16 is rotated clockwise, the claw 16a at the tip of the lever 16 is inserted into the gear 15, and the gear 15 is rotated by a force to pull the spring 18 upward. By performing the above operation, the toner layer thickness regulating member 6 can be rotated only in the direction opposite to the toner carrier 5.

Here, the force (torque) for rotating the developing roller 5 is represented by f (f within the above-mentioned pressing force range of the spring 7).
= 0.5 to 2.0 kgf · cm), the force of the spring 18 pulling the lever 16 upward is F, and the spring 18 has an elastic force such that f> F when the developing roller 5 starts rotating.
Is selected, the toner layer thickness regulating member 6 is slightly driven by the developing roller 5. However, since there is a movement limit of the lever 16, the layer thickness regulating member 6 stops in the state of FIG. Since f = 0 when the developing roller 5 stops, the lever 16 is pulled upward by the spring 18, and as shown in FIG.
The toner layer thickness regulating member 6 rotates in a direction opposite to the rotation direction of the developing roller 5. Thus, when the developing roller 5 is rotated and stopped, the toner layer thickness regulating member 6
Stops and reacts with the toner 2 and stays in the wedge-shaped space between the developing roller 5 and the toner layer thickness regulating member 6.
Is automatically eliminated.

The support shaft 17 and the spring 18
Is provided on the toner cartridge (not shown) side,
When the toner cartridge is replaced, the operator (user) may perform the same operation as described above to forcibly rotate the toner layer thickness regulating member 6. When the toner layer thickness regulating member 6 rotates in a direction opposite to the developing roller 5, the toner 2 attached to the surface of the toner layer thickness regulating member 6 appears on the surface. Therefore, as shown in FIG. 5, a toner wiping member 19 having elasticity is provided at the tip of the portion A of the toner container 1 to wipe off the toner 2 attached to the surface of the toner layer thickness regulating member 6, so that the toner is fixed. It is possible to reliably remove the toner. The toner wiping member 19 may be provided on the toner cartridge side, and may be replaced at the same time as the toner cartridge. Further, when a conductive material is used for the toner layer thickness regulating member 6, it is possible to apply a potential to stabilize the frictional charging of the toner 2 and to promote the supply of the toner 2 to the developing roller 4.

With the above configuration, in the normal state in which development is being performed, the toner layer thickness regulating member 6 is stopped with respect to the developing roller 5, and is rotated in a direction facing the developing roller 5 only when necessary. be able to. As a result, it is possible to eliminate the toner that has stayed or stuck in the wedge-shaped space formed between the toner layer thickness regulating member 6 and the developing roller 5. Therefore, since the staying or fixed toner does not damage the toner layer thickness regulating member 6 and the developing roller 5, it is possible to prevent the streaks appearing on the image and to stably obtain good image quality. .

Further, the surface of the toner layer thickness regulating member 6 is applied only in the longitudinal direction by a method such as sandblasting to a thickness of 10 to 150 μm.
Roughening within this range increases the contact area between the toner layer thickness regulating member 6 and the toner 2, that is, increases the number of contacts, increases the amount of triboelectric charging of the toner 2, and forms a stable thin toner layer. Leads to things. Further, if the image is damaged in the circumferential direction of the developing roller 5 and the image appears, or if filming of the toner 2 occurs on the surface of the developing roller 5, the image is developed on the surface of the toner layer thickness regulating member 6. The roller 5 is polished, and the developing roller 4 can be regenerated.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In the developing device of this embodiment, the lever 16 is configured to be pulled downward by the spring 18. Also, the lever 16
A pulling jig 20 for rotating the lever 16 in the circumferential direction is provided.

The rotation of the toner layer thickness regulating member 6 of this embodiment is performed as follows. With the developing roller 5 stopped, the pulling jig 20 is pushed down to rotate the lever 16 counterclockwise around the support shaft 17, and the claw 16 a at the tip of the lever 16 is disengaged from the gear 15. release. With the lever released, pull up the lever 16 upward, and engage the claw at the tip of the lever 16 with the next gear by one notch or more. When the lever 16 is released, the lever 16 is pulled downward by the pulling force of the spring 18 and the gear 15 rotates, and at the same time, the toner layer thickness regulating member 6 rotates in a direction opposite to the developing roller 5. Also, as shown in FIG.
The toner layer thickness regulating member 6 may be rotated by rotating the member 6 clockwise by 180 degrees. By operating in this manner, the same effects as in the above-described embodiment can be obtained.

FIG. 8 shows still another embodiment of the present invention.
This will be described with reference to FIG. In the developing device of this embodiment, the lever 2 is coaxial with the toner layer thickness regulating member 6.
1, a ratchet gear 22 having a tightening force in only one direction is provided therein. Normally, the lever 21 is fixed in a state where it is pushed down by a body cover (not shown) or the like, and the ratchet gear 22 is fixed by the fixing pin 23. It is in a stopped state without being driven by the roller 5.

Here, when the main body cover is opened due to toner replenishment, paper jam, or the like, the lever 21 pressed by the main body cover releases the pressing pressure. To rotate upward.
At this time, since the ratchet gear 22 is working, no tightening force is generated even when the lever 21 is rotated upward, and the toner layer thickness regulating member 6 is in a stopped state. When the main body cover is closed by eliminating the above-described cause, the lever 21 pivots downward, and a tightening force is generated only in that direction, so that the toner layer thickness regulating member 6 moves in the direction opposite to the rotation direction of the developing roller 5. To rotate.

The operator of the developing device having the above-described mechanism determines the image state of white stripes or the like, opens the main body cover, operates the lever 21 arbitrarily, and rotates the toner layer thickness regulating member 6. It is also possible to make it. According to the operation of this embodiment, the same effect as that of the above-described embodiment can be obtained.

In each of the above-described embodiments, the toner layer thickness regulating member 6 is disposed directly above the developing roller 5.
It is possible to form a similar uniform and stable toner thin layer on either the upstream side or the downstream side of the developing roller 5. In each of the above embodiments, the lever (16,
21) was manually operated, but an electromagnet is provided on the lever, or a motor is provided on the toner layer thickness regulating member 6, so that when the machine is turned on or off, every printed sheet, or after error processing, etc. Alternatively, the toner layer thickness regulating member 6 may be rotated. Further, even if the contact position is changed by substantially rotating the toner layer thickness regulating member 6 in a direction that follows the rotation of the developing roller 5, the toner fixed on the surface of the toner layer thickness regulating member 6 can be removed. The same effect can be obtained.

[0036]

As described above, according to the developing device of the present invention, the toner layer thickness regulating member has a substantially cylindrical shape and can be rotated appropriately, so that the toner layer thickness regulating member and the developing roller can be rotated. It is possible to eliminate toner staying in between as necessary, and to form a good toner thin layer while performing uniform and stable triboelectric charging. Therefore, the removability of staying and fixed toner is excellent with a simple structure, and white streaks hardly appear on an image. Further, since the toner layer thickness regulating member has a substantially columnar shape, the processing accuracy of the toner layer thickness regulating member can be easily improved, and there is a tolerance during mass production, and it is highly practical.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a developing device according to an embodiment of the present invention.

FIGS. 2A and 2B are a side view and a cross-sectional view illustrating a support / rotation mechanism of a toner layer thickness regulating member in a developing device according to an embodiment of the present invention. FIGS.

FIG. 3 is a cross-sectional view illustrating an operation state of a toner layer thickness regulating member in the developing device according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating an operation state of a toner layer thickness regulating member in the developing device according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration in which a toner wiping member is attached to the developing device according to one embodiment of the present invention.

FIG. 6 is a sectional view illustrating a mechanism for supporting and rotating a toner layer thickness regulating member in a developing device according to another embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a mechanism for supporting and rotating a toner layer thickness regulating member in a developing device according to still another embodiment of the present invention.

FIG. 8 is a sectional view showing a support / rotation mechanism of a toner layer thickness regulating member in a developing device according to still another embodiment of the present invention.

9 is a diagram illustrating a main part of a mechanism for supporting and rotating the toner layer thickness regulating member illustrated in FIG. 8;

[Explanation of symbols]

 Reference Signs List 1 toner container 2 toner 5 toner carrier (developing roller) 6 toner layer thickness regulating member 8 latent image holder (photosensitive drum) 15 gears 16 and 21 ... Lever 16a Claw 17 Support shaft 18 Spring 19 Toner wiping member 22 Ratchet gear 23 Fixing pin

Continuing from the front page (72) Inventor Shuichi Sato 1 Kosuka Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba Research Institute Co., Ltd. (72) Inventor Hiroki Takano 1, Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba Research Institute, Inc. (56) References JP-A-2-187779 (JP, A) JP-A Sho-59 -5253 (JP, A) JP-A-59-126567 (JP, A) JP-A-59-214056 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/08- 15/095

Claims (3)

(57) [Claims] 1. A toner carrier, a toner supply means for supplying toner to an outer peripheral surface of the toner carrier, and a substantially cylindrical toner layer thickness regulating member fixedly in contact with the outer peripheral surface of the toner carrier. The toner supplied to the outer peripheral surface of the toner carrier by the toner layer thickness regulating member is thinned, and this thin toner layer is brought into close proximity to or in contact with the latent image holding member, and held on the latent image holding member. A developing device for visualizing the formed electrostatic latent image, wherein the toner layer thickness regulating member is rotatable when desired and fixed during development. 2. The developing device according to claim 1, wherein said developing device holds and supplies the toner.
And a toner cartridge for supplying the toner cartridge.
When replacing a toner cartridge, the toner layer thickness
2. The control member according to claim 1, wherein the control member is rotated.
Developing device. 3. The developing device has a main body cover.
With the main body cover opened, the toner layer thickness regulating member is
When the body cover is opened and then closed again without rotating
Wherein the toner layer thickness regulating member is rotated.
The developing device according to claim 1.