JPH08328379A - One component developing device - Google Patents

Abstract

PURPOSE: To obtain an excellent image, by providing plural developer control members controlling the thickness of the developer on a developer carrier, and allowing to satisfactorily perform static charge of the developer, in a one component developing device. CONSTITUTION: This device is provided with a first blade 4a on the upstream side corresponding to the rotary direction of a developing roller 3, and the second blade 4b on the downstream side, in a state that respective end part of them as a free edge is abutted on the roller 3 while directing toward the downstream direction with regard to the rotary direction of the developing roller 3, via a holder 14 provided on a photoreceptor side tip of a case 2 of the developing device. In this way, the triboelectrication to the toner is performed twice by two pieces of blade 4a and 4b, therefore the static charge for the toner can be performed more thoroughly than the case only one blade is provided, and the toner attraction control onto the photoreceptor drum 1 can be excellently executed at the time of developing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a facsimile and a printer, and more specifically, to a developer carrying member in a developing device using a one-component developer. The present invention relates to stabilization of the toner adhesion amount and the toner charge amount.

[0002]

2. Description of the Related Art In an image forming apparatus in which an electrostatic latent image is formed on an image carrier and visualized by a developer, a one-component system is used from the viewpoints of downsizing of the developing apparatus, cost reduction, high reliability and the like. A developing device using a developer is advantageous. A developing device using a one-component developer stores a one-component developer on its surface and conveys it along a predetermined circulation path including a developing region, and stores the one-component developer. There is known one having a storage means and a developer supply means which is in contact with the developer carrying member and supplies the one-component developer stored in the developer storing means to the developer carrying member ( For example,
JP-A-60-229057, JP-A-61-426
No. 72).

In a developing device using these one-component developers (hereinafter referred to as toners), in order to obtain an appropriate toner adhesion amount and toner charge amount on the developer carrying member, a developing device made of a plate-like elastic body is used. A material using a material layer thickness regulating member has been proposed. For example, in the electrostatic copying machine Myricopy M10, a method is used in which the elastic magnetic plate is attracted to a magnet developing roller, and the toner layer thickness is regulated by the balance between the pressure and the force of the toner to push up the elastic magnetic plate. ing. Further, in a non-contact developing method using a magnetic developing roller, a portion where a developer bearing member and an image bearing member face each other (hereinafter,
An electrode member, which is a plate-like member having a control electrode and is composed of a magnet body, is provided in the upstream part of the developing area), and the electrode member is brought into contact with the developer carrier by magnetic force, and the toner is developed by the oscillating electric field. Has been proposed (for example, Japanese Patent Laid-Open No. 6-118799).
Further, a method has also been proposed in which a plurality of elastic plate-shaped members are pressed against the developer carrying member between the developer regulating member and the developing region to correct the toner spike defect on the developer carrying member. (For example, Japanese Utility Model Laid-Open No. 1-169266).

FIG. 1 is a front view showing a schematic structure of a conventional developing device using a magnetic one-component developer. This developing device is arranged on the side of a cylindrical photosensitive drum 1 which is an image carrier, and has a case 2 having an opening formed toward the photosensitive drum 1, and a part thereof is exposed from the opening. The developing roller 3 has magnetic toner on its surface, and a mini-agitator 5 as a toner supply member for supplying the toner in the toner hopper 6 as a toner storage portion onto the developing roller 3. Inside the toner hopper 6, there is provided an agitator 7 for conveying the toner to the mini agitator 5 side. Further, in this developing device, a blade 4 as a developer regulating member that comes into contact with the developing roller 3 via the toner carried on the developing roller 3 is provided. Is pressed against the developing roller 3 to even out the thickness of the toner layer, and the toner is triboelectrically charged.

In the above structure, the toner in the toner hopper is sent to the mini agitator 5 by the agitator 7, and the toner is further sent from the mini agitator 5 to the surface of the developing roller 3. The developing roller 3 holds the toner by a magnetic force, rotates in the direction of arrow A, and the surface thereof contacts the blade 4, whereby the thickness of the toner is uniformly regulated, and a charge is applied by frictional charging. On the other hand, the photosensitive drum 1 is uniformly charged by the charging roller 8,
The exposure light 9 forms an electrostatic latent image. The electrostatic latent image is regulated to have a uniform thickness on the developing roller 3, and toner charged with electric charges by frictional charging adheres to form a developed image. The developed image is conveyed from a sheet feeding device (not shown). The image is transferred to the transfer sheet by the transfer roller 10 and separated from the photosensitive drum 1. After the transfer, the residual toner is removed from the photosensitive drum 1 by the cleaning blade 11 provided on the left side of the drawing, and the residual charge is removed by a charge eliminating lamp (not shown). It is charged and ready for the next image formation.

FIG. 2 is a front view showing the main part of a conventional developing device using a non-magnetic one-component developer. In this apparatus, as a toner supply member to the developing roller 3, as shown in FIG.
The configuration is the same as that of FIG. 1 except that a sponge roller whose surface is formed of a sponge material is provided instead of the mini-agitator 5 of FIG. It is provided at the same position as.

When the layer thickness of the toner carried on the developing roller 3 is regulated by only one blade 4 and the toner is triboelectrically charged as shown in FIGS. 1 and 2,
By forming the toner layer on the developing roller 3 into a thin layer of about 1 to 2 layers, it is possible to prevent insufficient charging of each toner and to precisely control the toner adhesion to the photosensitive drum side during development. This prevents the problem that an image with good gradation cannot be obtained on the body drum.

Here, the amount of toner adhered to the photosensitive drum and the transfer paper depends on not only the amount of toner adhered on the developing roller 3 but also the relative speed between the photosensitive drum and the developing roller 3 in the developing area. To be done. As described above, in the conventional developing device, in order to cover the insufficient toner adhesion amount on the developing roller due to the thinning of the toner layer on the developing roller and to sufficiently develop a solid image. The developing roller linear velocity to the photosensitive drum linear velocity of 2
It has been set such that the photosensitive drum 1 and the developing roller 3 are brought into contact with each other at a setting of 4 times, so that a desired toner adhesion amount can be obtained on the photosensitive drum 1 or the like.

[0009]

However, when the linear velocity of the rotation of the developer carrying member is set to be high in order to cover the shortage of the toner adhesion amount on the developer carrying member in this way,
There have been various problems such as an increase in load on the drive system of the apparatus main body, a reduction in durability of the developing device, and toner scattering.

A desired toner adhesion amount can be obtained on the image carrier without causing such a load on the drive system of the main assembly of the apparatus, deterioration of durability of the developing apparatus, and toner scattering. In order to achieve this, the linear velocity of the developer bearing member should be brought closer to the linear velocity of the image bearing member, that is, closer to constant-velocity development, and the toner adhesion amount on the developer bearing member should be increased compared to the conventional case. is necessary. Specifically, in order to secure a sufficient amount of toner adhered on the image carrier or transfer paper by almost constant speed development, the amount of toner adhered on the developer carrier should be at least two toner layer thicknesses. Further, it is desirable that the toner charge amount distribution is stable.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a developing device using a one-component developer, in which two or more multi-layered toner layers are carried. It is an object of the present invention to provide a one-component developing device capable of obtaining a good developed image by sufficiently charging each of the particles of the developer on the developer carrying body while carrying the developer on the body.

[0012]

In order to achieve the first object, a one-component developing device according to claim 1 is a developer which moves while carrying a developer on the surface and conveys it onto an image carrier. A carrier, a developer supply member for supplying a developer to the developer carrier, and a development for contacting the developer carrier via the developer supplied on the developer carrier to regulate the thickness of the developer And a developer regulating member, wherein the developer carried on the developer carrying body is used to visualize the latent image on the image carrying body in a one-component developing device. It is characterized in that it is provided individually.

A two-component developing device according to a second aspect is the one-component developing device according to the first aspect, in which at least one of the plurality of developer regulating members has a free end which moves on the surface of the developer carrying member. Is provided so as to face the upstream side in the direction of contact with the developer carrying member, and the free end portion faces the downstream side at the downstream side in the moving direction of the surface of the developer carrying member with respect to the contact position of the developer regulating member. At least one developer regulating member is disposed so as to come into contact with the developer carrying member.

A third-component developing apparatus according to a third aspect is the one-component developing apparatus according to the first or second aspect, wherein the plurality of developer regulating members are formed of the same member.

A four-component developing device according to a fourth aspect is the one-component developing device according to the first or second aspect, wherein one or more developer regulating members are in contact with the surface of the developer carrying member. Is formed, and the plurality of developer regulating members are integrated with each other.

According to a fifth aspect of the present invention, there is provided a one-component developing device according to the first aspect.
In the one-component developing device of 2, 3 or 4, the contact pressure of the plurality of developer regulating members with the surface of the developer carrier is brought into contact with the developer carrier at the downstream side in the moving direction of the surface of the developer carrier. It is characterized in that it is set so that the smaller it is, the smaller it is.

[0017]

In the one-component developing device according to claim 1, the developer is supplied onto the developer carrier by the developer supplying member,
The developer is conveyed by the movement of the developer carrying body carrying the developer. Here, the plurality of developer regulating members form a plurality of positions where the surface of the developer carrying member and the developer regulating member come into contact with each other via the developer. Then, the developer on the developer carrying member is contact-charged multiple times by passing through these contact positions.

Particularly, in the one-component developing device according to the second aspect, the developer carried on the developer carrying body first comes into contact with the developer carrying body facing the upstream side in the moving direction of the developer carrying body. It passes between a developer regulating member (hereinafter, referred to as a first developer regulating member). By setting the projecting amount and the biting amount of the first developer regulating member with respect to the surface of the developer carrier, the wedge-shaped space formed on the upstream side of the contact portion between the first developer regulating member and the developer carrier is set. The size is such that the desired thickness of developer can pass between the contacts. As a result, the thickness of the developer on the developer carrying member is regulated by the first developer regulating member to the thickness of the developer required during development. Then, the developer carrying member and the developer regulating member (hereinafter referred to as the second developer controlling member) facing the downstream side in the moving direction of the developer carrying body and contacting each other.
In the developer regulating member), the thickness is regulated by the first developer regulating member, and only the developer having a thickness required for development is charged by friction.

Particularly, in the one-component developing device according to the third aspect, the same member is used for each developer regulating member, and the cost of the developer regulating member is reduced.

Particularly, in the one-component developing device according to the fourth aspect, one developer regulating member functions as a plurality of developer regulating members by contacting the developer carrying member at two or more places.

Particularly, in the one-component developing device according to the fifth aspect, each of the plurality of developer regulating members has a smaller contact pressure than the developer regulating member on the upstream side in the moving direction of the developer bearing member. Since the thickness of the developer is regulated by the developer regulating member on the most upstream side in the developer carrying member moving direction, the thickness of the developer is regulated by the developer regulating member on the downstream side and scraped off. Never be Therefore, the developer does not accumulate between the developer regulating members. Therefore, in the developer regulating member other than the most upstream side, the contact pressure of the developer regulating member to the developer carrying member does not change due to the presence of such accumulated developer, and Good charging can be achieved. (Hereinafter, margin)

[0022]

EXAMPLES Examples in which the present invention is applied to a developing device of an electrophotographic copying machine (hereinafter referred to as copying machine) which is an image forming apparatus will be described below. FIG. 3A is an enlarged view of the vicinity of the developing roller 3, which is a main part of the developing device according to this embodiment. This developing device may be a developing device using a one-component developer with magnetic toner, like the developing device of FIG.
As shown in the main part of FIG. 2, a developing device using a one-component developer made of non-magnetic toner may be used. In any case, the structure shown in FIG. 1 can be adopted as the structure of the entire apparatus. In FIG. 3A, in this embodiment, a first blade 4a is provided in addition to the second blade 4b provided at the same position as the blade in the conventional developing device, and a total of two blades are used. It has become.

The first blade 4a and the second blade 4
b is fixed to the case 2 of the developing device via holders 14a and 14b, respectively. Of these, the first blade 4
a is an upstream side with respect to the rotation direction A of the developing roller 3, and the second blade 4b is a downstream side, and the tip end as each free end is downstream with respect to the rotation direction A of the developing roller 3. It is provided so as to be oriented and to contact the surface of the developing roller 3 uniformly in the axial direction.

FIG. 3B shows a modified example of the holder. The holder 14 of this example has the first blade 4a and the second blade 4b in the example of FIG.
It is integrated into one holder. The holder 14 is provided on the side of the upper end of the case 2 on the side of the photoconductor that is bent upward by 90 degrees so as to face the photoconductor 1, and has two upper and lower protruding portions toward the photoconductor 1 side. Of these, the first blade 4a is on the lower protrusion and the second blade is on the upper protrusion.
The partial blades 4b each take the same posture as in the example of FIG. 3A, and are similarly fixed so as to contact the surface of the developing roller. Other configurations are similar to those of the example of FIG.

As shown in FIGS. 3 (a) and 3 (b), by providing the two blades 4a and 4b, the toner and the blade are triboelectrically charged twice, so that only one blade is provided. As compared with the case, the toner can be sufficiently charged, and the toner adhesion to the photosensitive drum 1 can be favorably controlled during development.

Next, an embodiment will be described in which a method of disposing the blades 4a and 4b that more effectively and uniformly charges the toner particles on the surface of the developing roller 3 is adopted. FIG. 4A is a front view showing the main part thereof. In this example, unlike the example shown in FIG. 3, the first blade 4a is arranged so that its tip as a free end faces the upstream direction with respect to the rotation direction A of the developing roller 3.

In the example of FIG. 4A, as in the example of FIG. 3A, two holders are used and the first blade 4a is used.
And the second blade 4b to the holders 14a, 14 respectively.
Although it is attached to b, as shown in FIG. 4 (b), two holders 14 a and 14 b are used by using one holder 14 in which the separately provided holders 14 a and 14 b are integrated.
May be fixed to the case 2 of the developing device.

The free end of the first blade 4a, which is in contact with the developing roller 3 on the upstream side with respect to the rotating direction A, is provided so as to face the upstream direction with respect to the rotating direction A of the developing roller 3. The function of the first blade 4a in the case of the following will be described. FIG. 5A shows a state where the first blade is pushed up by the developing roller 3.
(B) shows the positional relationship between the developing roller 3 and the first blade 4a when the first blade 4a is not deformed. Since the free end of the first blade 4a is in contact with the developing roller 3 with a constant contact pressure, the first blade 4a is pushed up by the developing roller 3 and deforms. Then, a wedge-shaped space s is formed between the contact point between the developing roller 3 and the first blade 4a and the surface of the developing roller 3 on the end side of the blade.

The size of the wedge-shaped space s is equal to that of the developing roller 3.
It is determined by the biting amount p and the protrusion amount i of the first blade 4a with respect to. In FIG. 5B, the first blade 4a
The difference between the distance between the developing roller 3 and the center of the developing roller 3 and the radial distance of the developing roller 3 is the bite amount p, and the perpendicular line of the first blade 4a passing through the center of the developing roller 3 and the first line exceeding the perpendicular line.
The distance from the tip of the blade 4a is the protrusion amount i.
By changing the biting amount p and the protruding amount i, the size of the wedge-shaped space s can be set to a desired size.

When the developing roller 3 and the blade come into contact with each other, the direction of rotation A of the developing roller 3 at the contact point thereof.
When the wedge-shaped space s is formed on the upstream side of the above, the amount of toner conveyed to the downstream side is regulated by the toner carried on the developing roller 3 passing through the wedge-shaped space s. To be done. At this time, the amount of toner conveyed downstream is determined by the size of the wedge-shaped space s.

The toner on the developing roller 3 which has passed through the contact point between the first blade 4a and the developing roller 3 continues to be the second toner.
It passes through the contact point between the blade 4b and the developing roller 3. Second
Since the blade 4b is pressed against the developing roller 3 so that its end portion faces the downstream direction of the developing roller 3 in the rotation direction A, a wedge-shaped space is also provided upstream of the contact point between the second blade 4b and the developing roller 3. Is formed. This wedge-shaped space is the first
Since it is much larger than the wedge-shaped space s formed by the blade 4a, the second blade 4b is pressed against the developing roller 3 with an appropriate contact pressure so that the second blade 4b passes between the first blade 4a and the developing roller 3. It is possible to allow all of the generated toner to pass through, and the second blade 4b can perform only the function of charging the toner by friction. Therefore, the toner conveyed to the developing area can be sufficiently charged, and a good image can be obtained.

As described above, when a plurality of blades are used, it is costly if the shapes of the first blade 4a and the second blade 4b are different.
If you use two same blades without changing the shape of 4b,
The cost can be reduced as compared with the case of using different blades.

Further, one blade member 15 which functions as two blades may be provided. 6 and 7
(A) thru | or (c) are the figures which used the blade member 15 which integrated the two blades.

FIG. 6 shows an example in which an intermediate connecting portion is provided at the ends of the two blades which are not in contact with the developing roller 3 and integrated. This blade member 15 is used for the case 2
An intermediate connecting portion is fixedly provided on the surface of the holder 14 having one side of the dogleg shape attached below the upper end portion thereof facing the developing roller 3 side. With the above configuration, the blade member 1
5, the first blade portion 15b below the developing roller 3
Upstream of the rotational direction A of the second blade portion 1
The downstream side 5b is uniformly in contact with the surface of the developing roller 3 in the axial direction so that the free end thereof is oriented downstream with respect to the rotation direction A of the developing roller 3.

FIGS. 7A to 7C show the blade member 1
5 shows an example in which the first blade portion 15a of No. 5 is provided so that its contact point faces the upstream direction with respect to the rotation direction A of the developing roller 3. FIG. 7A shows the blade member 1.
5 is formed into a dogleg shape by directly connecting at right angles without providing a connecting portion between the two blade portions 15a and 15b. This blade member is provided below a plate-shaped holder 14 horizontally attached below the upper end of the case 2.
The upper surface of the second blade portion 15b is fixed, the second blade portion 15b is provided horizontally, and the first blade portion 15a is provided so as to extend vertically downward. With the above configuration, the first blade portion 15a is in contact with the second blade portion 15b on the upstream side with respect to the rotation direction A of the developing roller 3, and at its contact point, the upstream direction with respect to the rotation direction A of the developing roller 3. It is facing.

FIG. 7B shows the blade member 15 as shown in FIG.
Similar to (a), the second blade portion is connected horizontally and the first blade portion 15a is connected at a right angle so as to face downward.
It shows an example in which a mounting portion 15c is provided at a right angle so as to be directed upward at an end portion of the blade portion 15b which is not connected to the first blade portion 15a. This mounting part is case 2
Is fixed to the tip of the holder 14 attached below the upper end of the holder so as to maintain the vertical state. The contact positions and directions of the first and second blade portions 15a and 15b with respect to the developing roller 3 are the same as those in FIG.

As shown in FIG. 7C, the first and second blade portions 15 of the blade member 15 shown in FIG. 7B are also provided.
The connection angle between a and 15b and the mounting portion 15c may be obtuse. Thus, by making the connection angle obtuse, the blade member 15 can be downsized, and the position where the first and second blade portions 15a and 15b contact the developing roller 3 and the distance between the two contact points. Can be set to a desired position.

As described above, when the blade member 15 in which two blades are integrated is used, not only when the shapes of the two blades are different but also when the two blades have the same shape. Also, the cost can be reduced, and the effect of using two blades can be obtained at the same cost as the case of using one blade.

As in the above embodiment, in the structure in which the thickness of the toner layer on the developing roller 3 is made uniform by the two blades and the toner is triboelectrically charged, the developing roller passing through the first blade 4a is used. If there is toner that does not pass through the second blade 4b among the toner on the third blade 3, the toner regulated by the second blade 4b is the first blade 4
There is a possibility that the toner is accumulated between a and the second blade 4b, and the accumulated toner may inadvertently change the contact pressure of the blade with respect to the developing roller 3. In order to prevent such a problem from occurring, the contact pressure of the blade on the developing roller 3 is set to the contact pressure of the first blade 4a on the second blade 4b.
The first and second blades 4b are brought into contact with the developing roller 3 so as to be larger than the contact pressure of the developing roller 3, and the developing device is configured so that the second blade 4b does not restrict the passage of the toner on the developing roller 3. May be.

[0040]

According to the one-component developing apparatus of claim 1, since the developer on the developer carrying member is charged a plurality of times by the plurality of developer regulating members, only one developer regulating member is provided. As compared with the case where it is not provided, there is an excellent effect that the developer can be sufficiently charged and a good image can be obtained.

According to the one-component developing device of the second aspect, the thickness of the developer on the developer carrier is required for development by the first developer regulating member which is in contact with the developer carrier relatively upstream in the moving direction. In the second developer regulating member that is regulated to a uniform thickness and contacts on the relatively downstream side in the same direction, only the developer necessary for development needs to be charged, so the charging efficiency of the developer is improved,
There is an excellent effect that a better image can be obtained.

According to the one-component developing device of the third aspect, since the same member is used for the plurality of developer regulating members, it is lower than the case where the developer regulating members of different standards are used. There is an excellent effect that a good image can be obtained at a cost.

According to the one-component developing device of the fourth aspect, since one developer regulating member functions as a plurality of developer regulating members, the cost is equivalent to that of providing only one developer regulating member. There is an excellent effect that a good image can be obtained.

According to the fifth aspect of the one-component developing device, the developer regulating member other than the developer regulating member which is in contact with the developer carrying member on the most upstream side in the moving direction of the surface of the developer carrying member is the developer. Since the thickness of the developer on the carrier is not regulated and the developer is not stored between the developer regulating members, the contact pressure between the developer regulating member and the developer carrier may change depending on the accumulated developer. Absent. Therefore, there is an excellent effect that the contact pressure between the developer regulating member and the developer carrying member can be kept constant and a good image can be obtained.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of a conventional developing device.

FIG. 2 is a front view of a main part of a developing device using a one-component developer made of non-magnetic toner.

FIG. 3A and FIG. 3B are front views of the main part of the developing device according to the embodiment.

FIG. 4A and FIG. 4B are front views of a main part of a developing device according to another embodiment.

FIG. 5A is an explanatory diagram of a state in which the first blade is pushed up by the developing roller. (B) is the first blade 4a
6 is an explanatory view of the positional relationship between the developing roller and the first blade when there is no deformation.

6 is a front view of an example in which the two blades in FIG. 3 are integrated.

7A to 7C are front views of an example in which the two blades in FIG. 4 are integrated.

[Explanation of symbols]

 1 Photoreceptor Drum 2 Support Case 3 Developing Roller 4 Blade 4a First Blade 4b Second Blade 5 Mini Agitator 6 Hopper 7 Agitator 8 Charging Roller 10 Transfer Roller 14 Holder 15 Blade Member A Developing Roller Rotating Direction p Projection Amount s Wedge-shaped space

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akira Sawada Akira Sawada 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Sathiko Baba 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Company Ricoh

Claims (5)

[Claims] 1. A developer carrying member that moves while carrying a developer on a surface thereof and conveys it onto an image carrying member, a developer supplying member for supplying the developer to the developer carrying member, and the developer carrying member. A developer regulating member that comes into contact with a developer carrier through the developer supplied above and regulates the thickness of the developer, and the image is formed by using the developer conveyed on the developer carrier. A one-component developing device for visualizing a latent image on a carrier, wherein a plurality of the developer regulating members are provided. 2. The one-component developing device according to claim 1, wherein at least one of the plurality of developer regulating members has a free end facing upstream in a moving direction of the surface of the developer carrier. It is provided so as to be in contact with the carrier, and at the downstream side of the contact direction of the developer regulating member in the moving direction of the surface of the developer carrier, its free end faces the downstream side and contacts the developer carrier. A one-component developing device characterized in that at least one developer regulating member is disposed in the. 3. The one-component developing device according to claim 1 or 2, wherein the plurality of developer regulating members are formed of the same member. 4. The one-component developing device according to claim 1 or 2, wherein the developer regulating member is formed so that two or more locations of one developer regulating member come into contact with the surface of the developer carrying member, and the plurality of developing units are developed. A one-component developing device characterized by integrating a developer regulating member. 5. The one-component developing device according to claim 1, 2, 3 or 4, wherein the contact pressure of the plurality of developer regulating members with respect to the surface of the developer carrying member is set to the downstream side in the moving direction of the surface of the developer carrying member. The one-component developing device is characterized in that it is set to be smaller as it comes into contact with the developer carrier.