JPH05281844A - Elastic blade for image forming device, developer container and developing device - Google Patents

Abstract

PURPOSE:To realize a developing device in which the abutting pressure of a developer regulating member to a developer carrier is not changed even under high-temperature environment. CONSTITUTION:In a developing device 3 provided with a developing sleeve (developer carrier) 30 and a developing blade (developer regulating member) 15 for regulating the layer thickness of toner (developer) T on the sleeve 30, the blade 15 is constituted of a bimetal blade(substance obtained by sticking an 'Invar(R)' plate 150 having a small thermal expansion coefficient to a phosphor bronze plate 151 having a large thermal expansion coefficient) which is deformed in accordance with temperature. Even when the blade 15 receives force in a direction where it separates from the sleeve 30 under the high- temperature environment, the force that the blade 15 is allowed to approach to the sleeve 30 is generated on the blade 15 by the action of bimetal, so that the blade 15 is allowed to abut on the sleeve 30 with fixed pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastic blade, a developing container and a developing device used in an image forming apparatus such as an electrophotographic copying machine, an electrostatic recording device and a laser beam printer.

[0002]

2. Description of the Related Art For example, in a developing device used in an image forming apparatus such as a copying machine, a developing blade made of an elastic member such as a rubber member is in contact with an outer surface of a developing sleeve which is a rotating member. The developing blade itself is in contact with the developing sleeve under pressure by the action of an elastic force generated when the developing blade is displaced by a predetermined amount, and rubs the developing sleeve as the developing sleeve rotates. It has a function of uniformly regulating the layer thickness of the developer (hereinafter referred to as toner) adsorbed and held on the outer peripheral surface of the developing sleeve by the action of magnetic force, and frictionally charging the toner to frictionally charge the same. ..

However, when such a developing blade is used for a certain period of time, it is permanently deformed and the contact surface with the developing sleeve is worn. Therefore, the pressure applied to the developing sleeve side of the developing blade changes, the layer thickness of the toner on the developing sleeve becomes non-uniform, so-called fog occurs in the image, the sharpness of the image decreases, or Due to insufficient charging of the toner, the image density is reduced and the image is uneven or fogged. In addition, due to the abrasion of the developing blade, streaks and the like are generated in the image. Therefore, the developing blade needs to be replaced with a new one after being used for a predetermined time.

In the conventional developing device or process cartridge of an image forming apparatus, when the finite amount of toner stored in the developing container decreases, the developing container or process cartridge is shaken to remain inside the developing container. Can be moved toward the developer carrying member (hereinafter referred to as the developing sleeve), or a stirring member for feeding the developer can be provided in the developing container to constantly or intermittently move the toner toward the developing sleeve. It was being done.

On the other hand, in an image forming apparatus adopting an electrophotographic system or an electrostatic recording system, when an electrostatic latent image is formed on a photosensitive drum which is an image carrier, the electrostatic latent image is developed by a developing device. It needs to be visualized as a toner image.

A conventional example of the above-mentioned developing device will be described with reference to FIG. 17. The developing device 103 shown in the drawing develops at a position spaced apart from the developing device main body 102 holding toner and the like and the photosensitive drum 101 by a predetermined distance. The apparatus main body 102 includes a developing sleeve 130 as a developer carrier that is pivotally supported and rotates while adsorbing toner on the outer peripheral surface thereof.

When the image forming operation is started and an electrostatic latent image is formed on the photosensitive drum 101, the developing sleeve 130 adsorbs toner on the outer peripheral surface of the developing sleeve 130 and rotates, and the toner rotates. A bias voltage is applied to the developing sleeve 130 at the time when the electrostatic latent image of 101 is opposed, and the toner on the developing sleeve 130 flies to the photosensitive drum 101 side to visualize the electrostatic latent image as a toner image. To do.

A developing blade 115, which is made of an elastic material such as rubber or metal, as a developer regulating member is in contact with the outer peripheral surface of the developing sleeve 130, and the developing blade 115 rotates the developing sleeve 130. Along with this, the layer thickness of the toner on the developing sleeve 130 is regulated to form a thin layer, and then the toner is moved to the photosensitive drum 101 side. Further, since the developing blade 115 forcibly rubs the toner on the developing sleeve 130, it is possible to always give a stable and high charge amount to the toner, and as a result, an image with high density can be obtained.

As shown in FIG. 17, the developing blade 115 has a plastic developing device main body 102, one end of which is made of a metal supporting plate 104 and screws 105.
It is fixed to the support portion 102a of.

[0010]

By the way, even if the developing blade is replaced with a new one after being used for a predetermined time as described above, the developing blade actually has a relatively short durability time, and each time the developing blade is replaced with a new one. Since it has to be replaced with a new one, there is a problem in that the operating cost increases. Although it is possible to reuse the developing blade from the viewpoint of resource reuse, it is difficult to reuse the conventional developing blade due to its structure.

The above problem applies not only to the developing blade of the developing device but also to all the elastic blades in contact with the rotating device in the image forming apparatus.

Therefore, an object of the first invention is to provide an elastic blade of an image forming apparatus which is easy to reuse and can reduce the operating cost of the image forming apparatus and save resources. It is in.

On the other hand, in the conventional developing container, the inclination angle of the inclined surface (toner storage portion) is constant regardless of the amount of toner consumed, and therefore the number of times of shaking is increased.
In some cases, the guideline for the replacement time may not be met.

Further, when the developing container is shaken, the toner is deviated in the developing container, and there may be a case where an image is partially missing in spite of the presence of the residual toner. The toner in the container blows off to cause stains, and particularly in a process cartridge having a cleaning device, scattering of waste toner from the cleaning device may cause contamination of the drum and the charging device, resulting in an image defect. ..

Further, if a stirring member is provided in the developing container,
The drive torque of the developing device or the process cartridge increases, image formation becomes impossible due to drive abnormality, or vibration increases to cause optical (lens system image or laser beam) blurring, resulting in uneven pitch on the image. There was something. In particular, a gear train for stirring is required when the process cartridge is constructed, which may be an obstacle to downsizing and cost reduction of the apparatus. Further, the charging performance of the toner is deteriorated due to the collision between the stirring member and the toner, a partial difference occurs in the ratio of the toner and the external additive, and the deterioration of the image density or the like is induced. In some cases, the fusion of the toner occurs due to the rotation, the movement axis portion being remarkable).

By the way, FIG. 16 shows a conventional developing container 120.
In the process cartridge including the above, the toner in the developing container 120 is filled in the area A1 on the left side of the broken line A at the beginning of use, and the toner can be sufficiently supplied in the direction of the developing sleeve 130. As the consumption of the toner advances, the toner deviates to the areas B1 and B2 shown by the chain double-dashed line B, and the area B
The toner remaining in No. 2 is not used for development.
At this time, the inclination angle of the outer wall 107 of the developing container 120 is θ1 shown in the figure, and the inclination angle is θ2 (> θ1) shown in the figure from the beginning.
However, as the inclination angle is increased from θ1 to θ2, the initial toner storage amount is decreased and the life of the developing device or the process cartridge is shortened.

Therefore, an object of the second invention is to provide a developing container for an image forming apparatus in which the developer can be used up to the end without waste and without any harmful effect.

On the other hand, the conventional developing device 10 shown in FIG.
In the case of No. 3, the developing blade 115 is in contact with the developing sleeve 130 with a uniform pressure at room temperature, but in a high temperature environment, the contact pressure of the developing blade 115 with respect to the developing sleeve 130 is reduced, and There is a problem that the amount of charge is reduced and the image density is reduced.

The above-mentioned development is caused by a difference in thermal expansion between the plastic support portion 102a supporting the developing blade 115 and the metal support plate 104, and the support plate 104 in a high temperature environment. The support portion 102a is distorted in the arrow C direction in FIG. 17 due to the difference in thermal expansion between the support portion 102a and the support portion 102a, and therefore the contact portion of the developing blade 115 with the developing sleeve 130 is also pulled in the arrow C direction. Occurs. Therefore, for example, when phosphor bronze is used as the material of the developing blade 115, as shown in FIG. 18, the contact pressure of the developing blade 115 with the developing sleeve 130 decreases substantially linearly with the temperature rise.

Therefore, an object of the third invention is to provide a developing device in which the contact pressure of the developer regulating member against the developer does not change even in a high temperature environment.

[0021]

In order to achieve the above object, the first invention is such that the length of a fixing region portion which is fixed by pressure by a supporting member of an elastic blade of an image forming apparatus is changed from the fixing region portion side to the rotating body side. Longer than the length of the free end side area that extends to
In addition, it is characterized in that the fixed area portion and the free end side area portion are replaced with each other for reuse.

In the second aspect of the invention, in the developing container of the image forming apparatus in which a fixed amount of the developer is stored, the shape of the developer storage section is changed according to the amount of the developer used to carry the developer. Its characteristic is that it is easy to move in the direction.

Further, according to a third aspect of the invention, a developer carrying member that rotates while adsorbing the developer on the outer peripheral surface thereof and moves the developer to the image carrying member side, and one end thereof is supported on the developing device main body side, In the developing device, the other end side is in contact with the surface of the developer carrier, and a developer regulating member for regulating the layer thickness of the developer on the developer carrier moving to the image carrier is provided. The feature is that the member is composed of a bimetal blade that is deformed by temperature.

[0024]

When the elastic blade for the rotating body composed of the elastic body is used in a pressurized state for a predetermined time, one end side of the supporting member of the elastic blade, that is, the boundary portion between the fixed area portion and the free end side area portion A permanently deformed bent portion is generated, and the amount of pressure applied to the rotating body by the elastic blade changes.

Therefore, in the first invention, the length of the fixed region portion of the elastic blade is made longer than the length of the free end region portion, and when the permanent deformation occurs, the fixed region portion and the free end side region portion are exchanged. Made possible The bent portion of the elastic blade by incorporating such a fixed region portion and the free end side region portion is incorporated into the fixed region portion side, and is fixed under pressure by the supporting member, so that it is returned to the original state without permanent deformation, As a result,
The elastic blade can slide on the rotating body with a predetermined pressing force by a predetermined amount of elastic deformation. Further, since the fixed area portion of the elastic blade is not used, the fixed area portion is not worn or the like, and the elastic blade can be reused in a state similar to that of a new article.

According to the second aspect of the invention, when the developer is consumed, the shape of the developer storage portion (outer wall) is changed to increase the inclination angle of the developer storage portion from the initial one, or the developer storage portion is stored. If the part is brought close to the developer carrying member side, all the developer remaining in the developing container moves to the developer carrying member side and is used for development, so that the developer can be used up to the end without waste, The life of the developing device or the process cartridge can be extended. In this case, since it is not necessary to shake the developing container or the process cartridge and to provide the stirring member as in the conventional case, contamination due to scattering of the developer, image white spots, image defects such as image pitch unevenness, etc. do not occur.

Further, according to the third aspect of the invention, since the developer regulating member is composed of the bimetal blade which is deformed by temperature, the influence of the thermal expansion of the supporting portion of the developer regulating member is offset, and the developer by the developer regulating member. The contact pressure on the carrier can be kept constant even in a high temperature environment.

[0028]

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

First, a first embodiment of the first invention will be described with reference to FIGS.

FIG. 3 is a vertical sectional view of the copying machine. In FIG.
Reference numeral 1 denotes a photosensitive drum (image carrier) which is an electrophotographic photosensitive member that rotates in the direction of the arrow in the figure. Around the photosensitive drum 1, process devices such as a corona charger 2, a developing device 3 and a cleaning device 4 are arranged. It is set up. Then, these process devices are integrally attached to the inside of the cartridge frame 5a, and the process main body 101 is formed as the process cartridge 5.
It is removably arranged in the inside to facilitate maintenance and the like.

A registration roller 6, a paper feed guide 7, and a transfer corona charger 8 are provided on the paper feed side below the process cartridge 5, and a conveyor belt 9 and a fixing device 1 are provided on the paper discharge side.
0, a paper discharge roller 11, and a paper discharge tray 12 are arranged. Further, the lamp 1 is provided above the process cartridge 5.
3, optical means such as the mirror 14 and the short focus optical element array 19 are provided, and the reflected light image (image light) of the original is exposed on the photosensitive drum 1 by the optical means. That is, when the image light is exposed on the photosensitive drum 1 uniformly charged by the corona charger 2 through the optical means such as the lamp 13, the mirror 14 and the short focus optical element array 19, the photosensitive drum 1 is exposed.
An electrostatic latent image is formed on the electrostatic latent image, and the electrostatic latent image is visualized as a toner image by the developing device 3.

On the other hand, the transfer material P in a paper feed cassette (not shown)
Are picked up one by one from the paper feed cassette and sent to the registration roller 6, and are sent to the photosensitive drum 1 via the paper feed guide 7 at a timing adjusted by the registration roller 6. The transfer material P sent to the photosensitive drum 1 is transferred by the transfer corona charger 8 to the toner image on the photosensitive drum 1, and then sent to the fixing device 10 via the conveying belt 9 and the fixing device 10 In 10, the toner image on the transfer material P is heated or the like and fixed as a permanent image. Then, the transfer material P on which the toner image has been fixed is discharged to the outside of the machine by the paper discharge roller 11, and is stacked on the paper discharge tray 12.

By the way, in the developing device 3, the toner T inside is attracted and held on the outer peripheral surface thereof by the action of the magnetic force and is rotated, and the toner T is supplied to the photosensitive drum 1. 30 and the developing sleeve 30
While controlling the layer thickness of the upper toner T to a uniform thin layer,
A developing blade 31 and the like for applying a triboelectric charge to the toner T are provided. Here, the developing blade 31 is made of an elastic body such as urethane or silicon rubber, and is in elastic contact with the developing sleeve 30 by being elastically deformed. The developing blade 31 has a thickness of the toner T
In consideration of the layer thickness, the amount of triboelectric charge on the toner T, and the damage to the toner T, the linear pressure on the developing sleeve 30 is 1 to 80 g.
In general, 2.0 to 0.6 m so that the range is / cm.
It is set to about m. A coating layer of charge control resin or rubber may be separately provided on the side of the contact surface of the developing blade 31 with the developing sleeve 30.

The toner T adsorbed and held on the developing sleeve 30 by the action of a magnet roll (not shown) disposed in the developing sleeve 30 is directed toward the developing blade 31 by the rotation of the developing sleeve 30. To the photosensitive drum 1 while being triboelectrically charged by the developing blade 31 and being regulated by a uniform thin layer. Then, the toner T that has moved to the photosensitive drum 1 side is flown to the photosensitive drum 1 side by the developing bias voltage applied to the developing sleeve 30 at the same timing as the electrostatic latent image on the photosensitive drum 1, and the electrostatic latent image. Is developed as a toner image.

By the way, the developing blade 31 is made of an elastic material as described above, and as shown in FIG. 2A, the developing blade 31 contacts the developing sleeve 30 with the surface A separated from the edge portion R. At this time, since the displacement amount L of the edge portion R is larger than the thickness of the developing blade 31, stress is concentrated on the lower end portion of the supporting plate 32 of the developing blade 31 by using the developing blade 31 for a predetermined time, The developing blade 31 is permanently deformed in the state where a large bent portion Q is formed on the lower end side. Therefore, the pressing force of the developing blade 31 on the developing sleeve 30 side changes, the layer thickness of the toner T on the developing sleeve 30 cannot be sufficiently regulated, and the rubbing between the developing blade 31 and the toner T does not occur. It becomes sufficient, and the toner T cannot be sufficiently charged by friction.

Here, it is conceivable to replace the upper and lower parts of the developing blade 31 with each other and reuse the developing blade 31, but the length of the fixed region portion 31A supported by the supporting plate 32 of the developing blade 31. Since the length L2 of the free end side region 31B extending from the fixed region 31A to the developing sleeve 30 side is longer than L1 (L1 <L2), it is impossible to reuse the developing blade 31 in an appropriate state. Become. That is, as shown in FIG. 2B, the upper and lower sides are simply interchanged, the upper and lower sides and the front and back sides are interchanged as shown in FIG. 2C, and the front and rear sides are shown as shown in FIG. Even if the bending point Q is replaced,
Since it is located on the side, the free end region portion 31B is shown in FIG.
As indicated by a broken line, the fixed area portion 31A does not extend straight downward and is bent. Therefore, when such a developing blade 31 is curved and brought into contact with the developing sleeve 30, the contact pressure changes, which is not appropriate.

Therefore, in the present embodiment, as shown in FIG. 1, the length L of the fixed area portion 31A of the developing blade 31 is L.
1 is made longer than the length L2 of the free end side region portion 31B (L
1> L2), and the fixed area portion 31A of the developing blade 31
The back and front sides of the sheet were held and sandwiched by the support plates 32 and 33 under pressure. Even when the upper and lower portions of the developing blade 31 are exchanged, the bent portion Q of the developing blade 31 is changed to the supporting plates 32, 33.
So that the developing sleeve 31 can be pressed and sandwiched so as to be corrected straight, and the developing blade 31 can be reused by replacing the upper and lower sides of the developing blade 31 with the proper contact pressure. I chose A specific example will be described below.

The supporting plate 32 on the back side of the developing blade 31 is made of a rigid sheet metal of iron or aluminum having a thickness of about 1.2 to 1.6 mm (which may be a mold forming part of the main body of the developing device 3). ), And a flange portion 32a is formed in the upper portion, for example, to keep the flatness high. or,
The supporting plate 33 on the front surface side of the developing blade 31 is the same in thickness and material as the supporting plate 32 on the rear surface side, and has a collar portion 32a on the upper portion.
However, even if the lower end of the developing blade 31 is at the same position as or shorter than the supporting plate 32, when the upper and lower parts of the developing blade 31 are replaced, the bent portion Q is supported by the supporting plate 32. It must be in a position where it can be pressed sufficiently to the side. Then, the fixed region portion 31A of the developing blade 31 is pressed and sandwiched between the support plates 32 and 33 and held. The developing blade 31 is made of polyurethane rubber having a thickness of 1 mm, and the length L1 of the fixed region portion 31A is 8 m.
m, the length L2 of the free end side region portion 31B was 7 mm, the displacement amount L of the edge portion R was 4 mm, and the contact pressure (line pressure) to the developing sleeve 31 was 9 g / cm.

The developing blade 31 is attached to the supporting plates 32, 3
3 to the developing device 3 in the process cartridge 5 and the non-contact jumping developing method using the developing device 3 with various toners T such as magnetic one-component toner and non-magnetic one-component toner having a particle size of 6 to 13 μm. It was possible to obtain a good image. When the process cartridge 5 is left for a long period of time beyond its life or is used for a long period of time, the developing sleeve 30 of the developing blade 31 of the developing device 3
The contact pressure on the surface of the image dropped to 5 g / cm, and the image had reduced density, fog, and streaks.

Therefore, the contact surface A of the developing blade 31 to the developing sleeve 30 remains the same, and
The upper and lower parts are replaced with each other, and the bent portion Q formed on the lower end side of the support plate 32 on the back surface side is pressed and sandwiched by the two support plates 32 and 33, and the developing blade 31 is reused. With such a developing device 3, a good image without density reduction, fog, and streaks, which is almost the same as that of a new product, was obtained.

Then, the upper and lower parts of the developing blade 31 are replaced with each other, the fixed area portion 31A is brought into contact with the developing sleeve 30 side as the free end side area portion 31B, and the free end side area portion 31B is supported as the fixed area portion 31A. Since the bent portions Q are straightened by being supported by the plates 32 and 33 by pressure sandwiching, the displacement amount L of the developing blade 31 is 4 mm as in the initial case.
The contact pressure to the developing sleeve 30 due to is almost the initial value (9 g
/ Cm). Therefore, the contact pressure of the developing blade 31 is restored, and the layer thickness of the toner T on the developing sleeve 30 is regulated by the developing blade 31 to be a uniform thin layer, and the triboelectric charge of the toner T is also improved. .. Further, since the portion newly formed as the free end side area portion 31B due to the upper and lower replacement of the developing blade 31 is unused and has not been worn or the like, it can be obtained by the developing device 3 using the developing blade 31. No streaks or the like appear in the displayed image.

As a result, by replacing the upper and lower developing blades 31 and reusing them, it is possible to obtain the same effect as when the developing blade 31 is replaced with a substantially new one, and it is possible to easily reduce the operating cost. You can

Here, when the developing blade 31 is replaced with the upper side and the lower side, the contact surface with respect to the developing sleeve 30 remains the same, but this is because the developing blade 31 has charge control on the contact surface side. This is because the coating layer is provided, and it goes without saying that the initial contact surface may be the back surface side when there is no such coating layer.

Further, the developing system of the developing device 3 according to the present embodiment is not limited to the non-contact jumping system, but may be the system in which the toner T on the developing sleeve 30 contacts the photosensitive drum 1. Of course.

Next, a second embodiment of the first invention will be described with reference to FIG. In FIG. 4, those having the same functions as those in the first embodiment are designated by the same reference numerals, and description thereof will be omitted below.

In this embodiment, the first invention is applied to the cleaning blade 40 used in the cleaning device 4. The cleaning blade 40 has its edge portion R pressed against the surface of the photosensitive drum 1 to scrape off the residual toner on the photosensitive drum 1 to clean the photosensitive drum 1.
Is also made of an elastic body, and the edge portion R is brought into contact with the photosensitive drum 1 by the elastic force due to its deformation or the force by a spring or the like. Also in this case, the stress is concentrated on the lower end side of the support plate 41, and a permanent deformation state bent portion Q is generated on the lower end side of the support plate 41 of the cleaning blade 40 by using for a predetermined time, and the cleaning blade 40 Insufficient contact pressure on the photosensitive drum 1 side causes cleaning failure.

Therefore, the back side and the front side of the cleaning blade 40 are pressed and sandwiched by support plates 41 and 42 having the same structure as the support plates 32 and 33 according to the first embodiment, and are supported. The length L of the fixed region 40A of the cleaning blade 40 supported by the support plates 41, 42
1 is longer than the length L2 of the free end side region 40B extending from the fixed region 40A to the photosensitive drum 1 side (L1> L).
2), the contact pressure of the cleaning blade 40 is insufficient,
When the cleaning blade 40 reaches the service life, the upper and lower parts of the cleaning blade 40 are replaced so that the cleaning blade 40 can be reused.

Therefore, also in this embodiment, the same effect as that of the first embodiment can be obtained. In addition, in FIG.
2'is a charging roller having the same function as the corona charger 2,
Reference numeral 8'denotes a transfer roller having the same function as the transfer corona charger 8.

Next, a third embodiment of the first invention will be described with reference to FIG. In FIG. 5 as well, those having the same functions as those in the first embodiment are designated by the same reference numerals, and description thereof will be omitted below.

In this embodiment, a charging blade 50 having the same function as the corona charger 2 that uniformly charges the photosensitive drum 1.
This is the case where the first invention is applied to. This charging blade 5
0 is 3 of the electrode layer 50a, the resistance layer 50b and the surface layer 50c.
The resistance value is controlled to be a predetermined value, and the edge portion R on the surface layer 50c side is in pressure contact with the photosensitive drum 1 side. A bias power source 53 is connected to the charging blade 50 via a support plate 51 that also acts as an electrode, and the charging blade 50 allows the charging blade 50 to have a predetermined DC voltage twice the discharge start voltage. A charging voltage on which the AC voltage having the above peak voltage is superimposed is applied to the photosensitive drum 1 side, and the photosensitive drum 1 is uniformly charged.

Since the charging blade 50 is also made of an elastic material, the supporting plate 5 can be used for a predetermined time.
A permanently deformed bent portion Q is generated at the lower end of the photosensitive drum 1, and the contact pressure of the charging blade 50 with respect to the photosensitive drum 1 is changed to cause defective charging.

Therefore, the back side and the front side of the charging blade 50 are pressed and sandwiched by the support plates 51 and 52 to be supported, and the fixed area portion 5 supported by the support plates 51 and 52 is also provided.
0A length L1 from the fixed region 50A to the photosensitive drum 1
If the contact pressure is insufficient for the charging blade 50 by making it longer than the length L2 of the free end side region portion 50B extending to the side (L1> L2), and this reaches the end of its service life, the charging blade 5
I replaced the top and bottom of 0 so that I could reuse it.

Therefore, also in this embodiment, the same effect as in the first embodiment can be obtained. In FIG. 5, S
Is image light for exposing the photosensitive drum 1.

Next, an embodiment of the second invention will be described with reference to the accompanying drawings.

FIG. 6 is a longitudinal sectional view of a process cartridge showing a first embodiment of the second invention. The process cartridge is attachable to and detachable from the main body of an image forming apparatus (not shown). And a photosensitive drum 1 around the photosensitive drum 1, a charging roller 2 for charging the photosensitive drum 1, a cleaning device 4 for cleaning the surface of the photosensitive drum 1, and an optical image. Slit 1 for
6 and the developing device 3 are provided.

The developing device 3 has a developing sleeve 30 which is a developer carrying member and a developing blade 31 which comes into contact with the developing sleeve 30, and the developing sleeve 31 is uniformly coated with a thin layer of toner. The developing sleeve 30 is a hollow cylinder having a magnetic force generating member inside, and is made of metal or conductive plastic, or its surface is coated with metal or conductive plastic. The developing sleeve 30 does not necessarily have a magnetic force generating member inside, and may be constituted by an elastic roll. Whether the developing portion is non-contact or contact type, magnetic toner or non-magnetic toner. Any one can be selected depending on whether or not to use.

Further, the outer walls 17, 18 of the toner storage portion of the developing container 20 of the developing device 3 are configured to be bendable by the hinges 21, 22, 23, and at the initial stage of use of the process cartridge, the outer walls 17, 18 are formed. As shown by the solid line in FIG. 6, 18 has a posture in which the inclination angles are θ1 and θ3, respectively, and at this time, the volume of the developing container 20 is the maximum, and the toner is inside the chain double-dashed line A. It is stored in the area A1 partitioned by.

When the toner is consumed and reduced by the image formation, the outer wall 1 as shown by the broken line in FIG.
7 and 18 are deformed to the developing sleeve 30 side, and 17 'and 1
When the outer wall 17 is moved to the position 8 ′, the inclination angle θ2 of the outer wall 17 becomes larger than the initial inclination angle θ1 (θ2> θ1).
The remaining toner moves to the developing sleeve 30 side along the steeply inclined outer wall 17 ′ and concentrates on the area B1 defined by the broken line B in FIG. Consumed. As a result, the life of the developing device 3 or the process cartridge can be extended.

Further, according to the present embodiment, since it is not necessary to shake the developing container 20 or the process cartridge and to provide a stirring member as in the conventional case, contamination due to toner scattering, image white spots, image pitch unevenness, etc. It is possible to effectively solve the problem of occurrence of defects.

The initial inclination angles θ1 of the outer walls 17 and 18 are
As θ3, 0 ° <θ1 <45 °, θ3 ≧ 45 °, and more preferably 60 ° ≦ θ3 <90 ° are set, and the outer wall 1
The inclination angle θ2 after the deformation of 7 is the same as the inclination angle θ3.
2 ≧ 45 °, more preferably 60 ° <θ3 <90 °.

When magnetic toner is used as the toner and the developing sleeve 30 has a magnetic force generating member inside, the shortest distance d between the hinge 21 and the developing sleeve 30.
(Mm) is set to M / d ≧ 40 (G / mm) with the magnetic force of the surface of the developing sleeve 30 at that portion being M Gauss (G), the magnetic force conveying force (attracting force in the developing sleeve 6 direction) is added. Thus, the toner can be consumed more effectively.

Next, a second embodiment of the second invention will be described with reference to FIG. FIG. 7 is a vertical sectional view of a process cartridge showing a second embodiment of the second invention, in which the same elements as those shown in FIG. 6 are designated by the same reference numerals.

In this embodiment, the outer wall 17 of the developing container 20 is configured to be rotatable about the hinge 21, and the outer peripheral portion 3a of the developing device 3 is formed into an arc shape in accordance with the locus drawn by the tip portion 17a of the outer wall 17. I am configuring.

Thus, in the initial stage, the outer wall 17 is at the position shown by the solid line in FIG. 7 and its inclination angle is set to θ1, and when the toner consumption progresses, the outer wall 17 is reversed about the hinge 21. By rotating clockwise to the broken line position 17 ′ and setting the inclination angle to θ2 (> θ1), the toner can be used up to the end without waste as in the first embodiment. In this embodiment, in order to prevent the toner from scattering due to the rotation of the outer wall 17, the tip portion 17a of the outer wall 17 needs to be made of flock, urethane foam or a rubber seal material.

FIG. 8 shows a third embodiment of the second invention.
8 is a vertical sectional view of a process cartridge showing a third embodiment of the second invention, and in this figure, the same elements as those shown in FIG. 6 are designated by the same reference numerals.

In the present embodiment, the outer wall 17 of the developing container 20 is configured to be movable in parallel from the solid line position to the broken line position shown in the figure, and the inclination angle θ1 of the outer wall 17 is kept constant and 45 ° <θ1. <90 °, more preferably 60 ° ≦ θ
It is set to 1 <90 °.

Thus, the outer wall 17 is initially in the position shown by the solid line in FIG. 8, and the maximum capacity is ensured in the developing container 20. By moving in parallel to the broken line position 17 'in the sleeve 30 direction), the toner can be used up to the end without waste as in the first and second embodiments.

By the way, for example, in the first embodiment, as shown in FIG. 9, the movement of the outer wall 18 is detected by a detection unit 24 such as a micro switch or a photo interrupter provided in the main body of the image forming apparatus, and this is detected. If a lamp is displayed on the display 26 via the detection circuit 25 or a signal sound is generated, the user can be notified that the process cartridge needs to be replaced. In particular, even when the power of the image forming apparatus is turned off by a large number of users, even when the power is turned on again, anyone can always know that the process cartridge needs to be replaced. Even if the process cartridge having the color developing device is inside the main body of the image forming apparatus and the process cartridge whose toner has been consumed is outside the main body of the image forming apparatus, the shape change of the process cartridge (outer wall 18) can be visually and touched. You can judge with your finger.

Next, an embodiment of the third invention will be described with reference to the accompanying drawings.

First, the first embodiment of the third invention will be described with reference to FIGS.

FIG. 10 shows a cross section of a process cartridge 100 which is removably arranged in the main body of the image forming apparatus. In the cartridge container 100a of the process cartridge 100, other than the photosensitive drum 1 which is an image carrier. The developing device 3, the charging roller 2 and the cleaning device 4 are integrally mounted.

The developing device 3 comprises a developing chamber 60 arranged on the photosensitive drum 1 side and a developer accommodating chamber 61 arranged on one side of the developing chamber 60 via a partition wall 62. A developer which is disposed in the developing chamber 60 so as to have a predetermined gap with the photosensitive drum 1 and which attracts the toner T magnetically to the outer peripheral surface thereof by the action of the internal magnet roller 34 to rotate in a predetermined direction. A developing sleeve 30 serving as a carrier, and a developer regulating member that abuts the developing sleeve 30 at a predetermined pressure to regulate the toner T on the developing sleeve 30 in a thin layer and imparts a predetermined amount of frictional charge to the toner T. The developing blade 15 and the like are disposed. Further, the developer accommodating chamber 61 is provided with a stirring member 67 that rotates in a predetermined direction and sends the toner T inside to the developing chamber 60 through an opening 66 provided in the partition wall 62.

The charging roller 2 is driven to rotate while being in contact with the outer peripheral surface of the photosensitive drum 1, and uniformly charges the photosensitive drum 1 to a predetermined polarity by applying a bias voltage. The cleaning device 4 contacts the outer peripheral surface of the photosensitive drum 1 and scrapes off the residual toner on the photosensitive drum 1, and a waste toner storage for storing the toner scraped off by the cleaning blade 4a. It is composed of a chamber 4b. A drum cover 27 is provided on one side of the photosensitive drum 1 and is automatically opened / closed when the process cartridge 100 is attached / detached to / from the image forming apparatus main body.

When the process cartridge 100 is mounted in the main body of the image forming apparatus and the image forming operation is started, the photosensitive drum 1 uniformly charged by the charging roller 2 is exposed through the exposure window 28. Image light L is exposed from a scanner unit (not shown), and an electrostatic latent image is formed on the photosensitive drum 1. The electrostatic latent image is directed toward the developing sleeve 30 of the developing device 3 as the photosensitive drum 1 rotates, and the toner T is supplied by the developing sleeve 30 to be visualized as a toner image. In this case, the toner T on the developing sleeve 30 is triboelectrically charged and moved to the photosensitive drum 1 side while the developing blade 15 regulates the layer thickness to a thin layer as the developing sleeve 30 rotates. When the electrostatic latent image of is moved to the vicinity of the developing sleeve 30, a developing bias in which an AC bias is superimposed on a DC bias is applied to the developing sleeve 30, and the toner T on the developing sleeve 30 is on the photosensitive drum 1 side. Then, the latent image is visualized as a toner image.

Then, the toner image on the photosensitive drum 1 is transferred onto a transfer sheet by a transfer charger (not shown). The residual toner on the photosensitive drum 1 after the transfer is cleaned by the cleaning device 4 and is prepared for the next image formation.

Here, the developing sleeve 30 is made of a non-magnetic material such as aluminum or stainless steel, and the outer peripheral surface thereof is processed by, for example, # 400 plast particles, and its surface roughness is JIS 10-point average roughness. Rz-2.
0 μm (the unevenness of the outer surface is preferably uniform, and Rz is preferably smaller than the average particle size of the toner particles). The peripheral speed of the developing sleeve 30 is 24
mm / sec, the developing bias is AC bias voltage Vpp = 1400V (Vpp = 500 to 3000V is suitable), and the same wave number f = 1800 Hz (f = 500 to 300).
0 Hz is appropriate), and the DC bias is the voltage Vdc =-
It is 500V. Further, the gap between the developing sleeve 30 and the photosensitive drum 1 is set to 300 μm (150 to 500 μm is suitable).

By the way, the developing blade 15 abuts on the developing sleeve 30 at a predetermined position with the abutting portion 15a on one end side facing the direction opposite to the rotating direction of the developing sleeve 30, and The end portion side is made of plastic which is the same material as the developing device body such as the supporting portion 63 provided on one side of the partition wall 62, the developing chamber 60 and the developer accommodating chamber 61, and the supporting plate 64 is made of a metal plate. Therefore, this developing device 3
Is placed in a high temperature environment, the contact portion 15a of the developing blade 15 receives a force in a direction to separate from the developing sleeve 30 due to a difference in thermal expansion between the supporting portion 63 and the supporting plate 64. Therefore, the contact pressure of the developing blade 15 with respect to the developing sleeve 30 changes so as to become small as shown in FIG.

Therefore, in the present embodiment, the developing blade 15
Is composed of a bimetal blade, and even if the developing blade 15 receives a force that separates it from the developing sleeve 30 in a high temperature environment, the bimetal action causes the developing blade 15 to move closer to the developing sleeve 30 side. A force is applied to bring the developing blade 15 into contact with the developing sleeve 30 at a constant pressure regardless of changes in the environmental temperature.

That is, the developing blade 15 is constructed by laminating an amber plate 150 having a small thermal expansion coefficient and a phosphor bronze plate 151 having a large thermal expansion coefficient, and as shown in FIG. 11, an amber plate 150 having a small thermal expansion coefficient. Developing sleeve 3 on the side
The developing blade 15 is fixed to the supporting portion 63 by the supporting plate 64 and the screw 23 so as to be in contact with 0. Then, at normal temperature, the developing blade 15 is freely placed at the position shown by the broken line in FIG. 11, and the developing sleeve 30 can be pressed with a desired predetermined pressure by the developing blade 15.

Thus, the amber plate 150 and the phosphor bronze plate 1
Due to the difference in the coefficient of thermal expansion of 51, the developing blade 15 tends to be displaced in the direction A in which the amount of penetration into the developing sleeve 30 becomes shallower at a temperature lower than room temperature, so that the supporting portion 63 and the supporting plate 64 are provided.
By offsetting the displacement of the developing blade 15 in the B direction due to
The developing blade 15 is held at the broken line position.

Therefore, even if the environmental temperature around the developing device 3 changes, the developing blade 15 is positioned at the position indicated by the broken line in FIG. 11 in its free state, and its abutting portion 15a contacts the developing sleeve 30. The contact pressure is always constant and the toner T on the developing sleeve 30 is triboelectrically charged in a constant state, so that unnecessary image shading does not occur in the toner image on the photosensitive drum 1.

Next, the specific structure of the developing blade 15 will be described with reference to FIGS.

Of the amber plate 150 and the phosphor bronze plate 151.
The linear expansion coefficients α1 and α2 are α1 = 0.1 × 10, respectively.^-Five
deg ^-1 , Α2 = 1.9 × 10^-Fivedeg^-1 And both
Difference α2-α1 is 1.8 × 10^-Fivedeg^-1Is. That
As shown in FIG. 12, the free end of the developing blade 15
The length is L (specifically 15 mm) and the plate thickness is h (specifically
The thickness of the amber plate 150 is 0.04 mm, phosphor blue
The thickness of the copper plate 151 is 0.04 mm.
It is bonded at a temperature of 0 ° C. to make h = 0.08 mm),
Change from the solid line state (100 ° C state) to the broken line state
ΔT is the temperature difference in the case of
Assuming that the displacement of the tip is x, the displacement x is expressed by the following equation.
It

[0084]

[Equation 1] And the displacement x of the above formula (1) is as follows:

[0085]

[Equation 2] Therefore, the developing blade 15 is in a slightly curved state. Then, in a curved state, the developing blade 15 is positioned at the position indicated by the broken line in FIG. Further, when the temperature changes from a normal temperature (20 ° C.) to a high temperature environment of 35 ° C., the temperature difference ΔT = 35−20 = 15 ° C., so the subsequent displacement amount x is

[0086]

[Equation 3] Then, the developing blade 15 is displaced by 0.77 mm in the direction of arrow B in FIG. 11, and tries to deepen the amount of invasion into the developing sleeve 30 side.

FIG. 13 shows the result of measuring the contact pressure of the developing blade 15 in the single product state as shown in FIG. 12 with respect to the developing sleeve 30, and the contact pressure is linear as the temperature rises. You can see that it is rising. In this case, the developing sleeve 30 having an outer diameter of 20 mm is inserted into one side of the developing blade 15, and therefore, the developing blade 15 is in a state in which its tip is displaced by 8 mm at room temperature (20 ° C.). ing.

Therefore, for example, in the developing device 3 in which the contact pressure of the developing blade 15 with respect to the developing sleeve 30 decreases in a high temperature environment, if the developing blade 15 is changed to the bimetal type developing blade 15 as described above, As shown in FIG. 13, the contact pressure with respect to the developing sleeve 30 does not fluctuate with a change in temperature and has a constant value.

Next, a second embodiment of the third invention will be described with reference to FIG. In FIG. 15, those having the same functions as those in the first embodiment are designated by the same reference numerals, and description thereof will be omitted below.

In this embodiment, the end side of the abutting portion 15a of the developing blade 15 is oriented in the rotation direction of the developing sleeve 30, and in this case, the supporting portion 63 and the supporting plate 6 are provided under a high temperature environment.
Due to the difference in thermal expansion of No. 4, the contact pressure of the developing blade 15 with respect to the developing sleeve 30 increases.

Even in this case, the developing blade 15 is composed of a bimetal blade composed of an amber plate 150 having a small linear expansion coefficient and a phosphor bronze plate 151 having a large linear expansion coefficient, and the amber plate 150 side is in contact with the developing sleeve 30. By doing so, under the high temperature environment, the phosphor bronze plate 151
Is larger than the amber plate 150, the contact pressure of the developing blade 15 with respect to the developing sleeve 30 is reduced, and the increase of the contact pressure of the developing blade 15 due to the support portion 63 and the like is offset, so that the first embodiment is different from the first embodiment. Similar effects are obtained.

[0092]

As is apparent from the above description, according to the first aspect of the present invention, the length of the fixed region portion of the elastic blade is made longer than the length of the free end side region portion, and the fixed region portion and the free end side region portion are formed. Since it is possible to replace and, even if this elastic blade reaches the end of its life, this elastic blade can be easily reused again in a substantially new state, and it is possible to reduce operating costs and save resources. The effect is obtained.

Further, according to the second aspect of the invention, in the developing container of the image forming apparatus in which a fixed amount of developer is stored, the shape of the developer storage section is changed according to the amount of developer used to develop the developer. Since the movement toward the agent carrier is facilitated, there is an effect that the developer can be used up to the end without waste and can be used up without any harmful effect.

Further, according to the third aspect of the invention, since the developer regulating member is constituted by the bimetal blade which is deformed by temperature, the developer regulating member is carried with a constant contact pressure even in a high temperature environment. The effect that it can be brought into contact with the body is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a developing blade and the like according to a first embodiment of the first invention.

FIG. 2 is a diagram for explaining a problem of a conventional type developing blade.

FIG. 3 is a side sectional view of the image forming apparatus.

FIG. 4 is an explanatory diagram of a cleaning blade for a cleaning device according to a second embodiment of the first invention.

FIG. 5 is an explanatory diagram of a charging blade and the like according to a third embodiment of the first invention.

FIG. 6 is a vertical cross-sectional view of the process cartridge showing the first embodiment of the second invention.

FIG. 7 is a vertical sectional view of a process cartridge showing a second embodiment of the second invention.

FIG. 8 is a longitudinal sectional view of a process cartridge showing a third embodiment of the second invention.

FIG. 9 is a vertical sectional view of a process cartridge showing another embodiment of the first embodiment of the second invention.

FIG. 10 is a vertical cross-sectional view of a process cartridge having a developing device according to the first embodiment of the third invention.

FIG. 11 is an enlarged view around the developing blade of the developing device according to the first embodiment of the third invention.

FIG. 12 is a diagram for explaining the amount of deformation of the developing blade of the developing device according to the first embodiment of the third aspect of the invention due to temperature change.

FIG. 13 is a diagram showing the relationship between temperature and contact pressure only due to the influence of bimetal deformation of the developing blade of the developing device according to the first example of the third invention.

FIG. 14 is a diagram showing the relationship between the contact pressure and the temperature of the developing blade of the developing device according to the first embodiment of the third invention.

FIG. 15 is a vertical sectional view of a process cartridge having a developing device according to a second embodiment of the third invention.

FIG. 16 is a vertical sectional view of a process cartridge according to a conventional example.

FIG. 17 is a vertical sectional view of a process cartridge having a conventional developing device.

FIG. 18 is a diagram showing the relationship between the temperature of the developing blade of the conventional developing device and the contact pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum (image bearing member) 3 Developing device 15 Developing blade (Developer regulating member) 17 Outer wall (developer storage section) 18 Outer wall (developer storage section) 20 Developer container 24 Detecting section 25 Detection detecting path 26 Indicator 30 Developing sleeve (developer carrying member) 31 Developing blade (elastic blade) 31A Fixed area portion 31B Free end side area portion L1 Length of fixed area portion L2 Free end side area length 150 Amber plate (bimetal blade) 151 Phosphorus Bronze plate (bimetal blade)

Claims (6)

[Claims] 1. An elastic blade of an image forming apparatus which is made of an elastic body and which rubs the rotating body in the image forming apparatus in a pressed state while rubbing the rotating body, the elastic blade being pressed and fixed by a supporting member. The length of the fixed region portion is longer than the length of the free end side region portion extending from the fixed region portion side to the rotating body side, and the fixed region portion and the free end side region portion can be replaced and reused. An elastic blade for an image forming apparatus. 2. In a developing container of an image forming apparatus which stores a fixed amount of developer, the shape of the developer storage section is changed according to the amount of the developer used to move the developer in the developer carrying direction. A developing container for an image forming apparatus, which is characterized by being made easy. 3. The developing container of the image forming apparatus according to claim 2, which constitutes an element of a process cartridge that is detachable from the main body of the image forming apparatus. 4. The image forming apparatus according to claim 2, wherein a change in shape of the developer storage unit is detected on the image forming apparatus main body side, and the state is displayed and warned on the image forming apparatus main body side. Development container of the device. 5. A developer carrying member that rotates while adsorbing the developer on its outer peripheral surface and moves the developer to the image carrying member side, one end of which is supported by the developing device main body side, and the other end of which is developed. In a developing device having a developer regulating member that is in contact with the surface of the agent bearing member and regulates the layer thickness of the developer on the developer bearing member that moves to the image bearing member side, the developer regulating member includes:
A developing device comprising a bimetal blade that is deformed by temperature. 6. The developing device according to claim 5, wherein the developer regulating member enters and deforms toward the developer carrying member side at a high temperature due to the effect of the bimetal.