JP2000155468A - Image forming device, developing device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming device, a developing device and a process cartridge constituted so that an excellent image can be formed extending over a long term by preventing one-component developer mechanically damaged and/or deteriorated in accordance with an image forming action from being left and stored in the developing device and preventing a member such as a developer carrier and a developer layer thickness regulation means from being deteriorated. SOLUTION: The image forming device, the developing device and the process cartridge are provided with the developer carrier 11 carrying and feeding the one- component developer, bringing it into contact with an image carrier 101 and developing an electrostatic latent image formed on the carrier 101, a developer supply means 13 supplying the one-component developer to the carrier 11 and a developer recovery means 13 recovering the one-component developer existing on the carrier 11 after making into contact with the carrier 101 from the carrier 11. Then, a developer reservoir T in which the one-component developer recovered from the carrier 11 by the recovery means 13 can be housed is formed. By preferentially using the one-component developer housed in the reservoir T, the electrostatic latent image formed on the carrier 101 is developed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for visualizing an electrostatic latent image formed on an image carrier using an electrophotographic system or an electrostatic recording system using a developing device to form a visible image. Thereafter, the present invention relates to an image forming apparatus for transferring and fixing the visible image on a recording material to obtain a permanent image, a developing device and a process cartridge used in the image forming apparatus.

Here, as an electrophotographic image forming apparatus, for example, a copying machine, a printer (for example, an LED printer, a laser beam printer, etc.), a facsimile machine,
And a word processor.

A process cartridge is a cartridge in which a charging means, a developer carrier or a cleaning means and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is made detachable from an image forming apparatus main body. Or at least one of a charging unit, a developer carrying member, and a cleaning unit and an electrophotographic photosensitive member are integrally formed as a cartridge so that the cartridge can be attached to and detached from the image forming apparatus main body. This means that the electrophotographic photosensitive member and the electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachable from the image forming apparatus main body.

[0004]

2. Description of the Related Art Conventionally, an image forming apparatus using, for example, an electrophotographic system has, for example, a schematic configuration shown in FIG.
That is, in the related art, in a substantially central portion of an image forming apparatus, for example, a drum-shaped electrophotographic photosensitive member (hereinafter, simply referred to as a “photosensitive member”) as an image carrier, that is, a photosensitive drum 10
When the image forming operation is started, the charging unit 108 uniformly charges the surface of the photosensitive drum 101, and then, for example, the LED 102 as an exposure unit And an electrostatic latent image is formed on the surface. Thereafter, the electrostatic latent image is visualized by the developer supplied to the photosensitive drum 101 by the developing device 103 to form a so-called toner image. Next, the toner image is electrostatically transferred onto the recording material P by a transfer electric field formed between the photosensitive drum 101 and the transfer roller 104 by, for example, a transfer roller 104 as a transfer unit. Thereafter, the unfixed toner image on the recording material P is permanently fixed on the recording material P by the fixing device 105 by heat and pressure.

The transfer residual toner remaining on the surface of the photosensitive drum 101 after the completion of the transfer of the toner image is, for example,
The photosensitive drum 101 is removed by the cleaning device 109 having the blade-shaped cleaning member, and is ready for image formation.

The developing device 103 used in the conventional image forming apparatus will be further described.

Conventionally, the developing device 103 uses a developer carrier made of an elastic material to transport the developer to the photosensitive drum 101, and this is brought into contact with the surface of the photosensitive drum 101 to form an electrostatic latent image. Those which perform image development are known. FIG.
1 shows a schematic configuration of an example of such a conventional developing device 103.

The developing device 103 shown in FIG. 11 uses a one-component developer as a developer, and particularly uses a non-magnetic one-component developer. In the following, unless otherwise specified,
The non-magnetic one-component developer is simply called “toner”.

In the developing device 103, the developing container 16 contains toner. The developing container 16 has an opening on a part facing the photosensitive drum 101, and the developing roller 11 as a developer carrier is rotatable in the direction of the arrow so as to be partially exposed from the opening. It is supported by. The developing roller 11 is formed of an elastic body and is in contact with the photosensitive drum 101.

A stirring paddle 1, which is a means for stirring and transporting the developer, is provided at the back of the developing container 16 opposite to the opening.
4 is provided rotatably in the direction of the arrow, agitating the toner, developing roller 11 and supply roller 13 to be described later.
Are conveying the toner to a region (region R) near the contact portion.

A supply roller 13 as a developer supply and recovery means is formed of an elastic body, and is provided so as to rotate in contact with the development roller 11. The toner conveyed by the stirring paddle 14 becomes uniform once in a region R in a dense state with the rotation of the supply roller 13 in the direction of the arrow. After that, as the developing roller 11 and the supply roller 13 come into contact with each other by the counter rotation, the toner is charged by friction. Here, the counter rotation refers to rotation in which opposing surfaces (sliding surfaces) advance in opposite directions.

The toner charged in the rubbing area between the developing roller 11 and the supply roller 13 is supplied to the developing roller 11 by receiving a mirror force due to the charged charge. Further, the developing container 16 is provided with a blade 12 as a developer layer thickness regulating member pressed against the developing roller 11, and the toner on the developing roller 11 is brought into contact with the blade 12 as the developing roller 11 rotates. Is applied to the developing roller 11 in a thin layer shape by regulating the layer thickness. In addition, the toner is provided with a sufficient charge for development by friction with the developing roller 11 and the blade 12 at this time.

Thereafter, the toner is conveyed to a developing area (developing nip) N where the photosensitive drum 101 and the developing roller 11 are in contact with the rotation of the developing roller 11. on the other hand,
A voltage is applied to the developing roller 11 from a power supply (not shown) between the photosensitive drum 101 and the developing roller 11, and a developing electric field is formed between the photosensitive drum 101 and the developing roller. Accordingly, the toner on the developing roller 11 is transferred to an electrostatic latent image on the photosensitive drum 101 by the action of the developing electric field, and a toner image is formed on the photosensitive drum 101. At this time,
As shown in FIG. 11, for example, in the case of a developing device that employs a method in which the developing roller 11 abuts and rotates on the surface of the photosensitive drum 101, toner that selectively adheres to a latent image to form a toner image, that is, contributes to development. Not only the toner but also the toner carried on the developing roller 11 is rubbed against the photosensitive drum 101. Such a state is referred to herein as a state in which the toner (developer) is brought into “contact” on the photosensitive drum 101.

Of the toner applied on the developing roller 11 and carried and transported to the developing nip N, the toner remaining on the developing roller 11 without contributing to the development is supplied to a supply roller (developer supply and peeling means). ) 13 to remove from the developing roller 11 by rubbing, a part of which is newly
The toner is supplied to the developing roller 11 again by the supply roller 13 together with the toner supplied to
It is returned to 6.

The conventional image forming apparatus forms an image by a series of operations as described above.

[0016]

However, in an image forming apparatus such as the above-described conventional image forming apparatus having a configuration in which development is performed while toner is in contact with an image carrier, the following problems arise. There is.

That is, the toner is rubbed between the supply roller 13 and the developing roller 11 in the order in which the toner is conveyed from the developing container 16, and the toner layer thickness between the blade 12 and the developing blade 12 is regulated. The rubbing and the rubbing between the photosensitive drum 101 and the developing roller 11 during the development are respectively received and provided for the development. Further, the toner that has not contributed to the development is peeled off from the developing roller 11 and collected in the developing container 16, so that the toner is rubbed again by the supply roller 13.

As described above, all of these series of operations associated with the image forming operation involve contact between the toner and the member, and the toner is repeatedly subjected to a load at each such contact. Due to such a load, a part or all of the toner in the developing container 16 is damaged and adheres to the developing roller 11 and the blade 12, and the frictional heat generated when the toner comes into contact with the members in the respective rubbing areas causes It fuses on the surface of the developing roller 11 and the blade 12. The fusion of the toner to the developing roller 11 and the blade 12 in this manner deteriorates the performance of these members.

Therefore, in an image forming apparatus having a schematic configuration as in the prior art, for example, a process speed of 100 m
When about 10,000 sheets of A4 size image were formed at about m / sec (corresponding to the peripheral speed of the photosensitive drum 101), it was sometimes necessary to replace members such as the developing roller 11 and the blade 12. .

That is, when the toner is fused to the surfaces of the developing roller 11 and the blade 12 as described above, the toner newly supplied onto the developing roller 11 and the developing roller 1
1 and the blade 12 are hindered from being triboelectrically charged, and it becomes impossible to impart a sufficient charge to the toner for development. As a result, the density of the formed image is reduced, the fogging of the non-image portion, the toner is scattered in the image forming apparatus, and the like, and good image formation cannot be performed.

Further, deterioration of members such as the developing roller 11 and the blade 12 due to fusion of the toner is related to recent technical development of the developer. That is, in recent years, the particle size of the developer has been reduced in order to respond to a demand for higher image quality. This includes the fact that fine spherical particles having a narrow particle size distribution and a narrow particle size distribution can be easily obtained by toner production methods using various polymerization methods. Furthermore, from the viewpoint of energy saving, so-called “on demand printing (on demand)
printing) ”, to lower the melting point of toner.
The softening point has also been remarkably reduced.

With such technical progress, the heat capacity per toner particle has sharply decreased, and the toner has easily melted even with a slight heat load. Therefore, toner fusion to the developing roller 11 and the blade 12
These performance degradations have come to be noticeable.

Therefore, as the process speed increases,
The frictional heat generated when the toner rubs with each member during the image forming operation increases, and the absolute amount of toner fused to the developing roller 11 and the blade 12 increases with the life of the apparatus. In such a case, the performance of the developing roller 11 and the blade 12 is significantly deteriorated, so that it is difficult to maintain a good image for a long period of time. Therefore, there is a problem that it is difficult to achieve high process speed and long life.

As described above, a part of the toner in the developing container 16 is mechanically damaged (such as melting and fusing by heat) due to a load associated with the image forming operation. However, even for the toner that has not been mechanically damaged, a load is applied in each rubbing region through the image forming operation, and additives such as silica externally added to the toner surface are embedded in the toner particles themselves, Due to the release or separation, the performance of the toner, such as fluidity and chargeability, required as a developer gradually deteriorates.

According to the studies made by the present inventors, the deteriorated toner is less likely to be used for development than the undegraded toner due to a decrease in chargeability and fluidity. 16 easily remains. As a result, it has been found that the toner is likely to be fused due to the load caused by the repeated contact with each member, which causes the performance of the developing roller 11 and the blade 12 to deteriorate.

In particular, in an image forming apparatus having a simple configuration having a so-called cleaner-less configuration without the cleaning device 109, the above-described problem becomes remarkable. That is, the cleanerless configuration is, for example, the photosensitive drum 10
Transfer residual toner (history of the toner image) after transferring the toner image on the image bearing member 1 (image carrier) is transferred to the developing device 1 at a contact portion between the photosensitive drum 101 and the developing roller 11 (developer carrier).
03, and the collected toner is reused. At this time, most of the toner collected from the image carrier has been damaged or deteriorated. Therefore, by collecting them in the developing container, the absolute amount of the damaged or deteriorated toner in the developing device is reduced. To increase.

In the case where a toner having an internal structure is used as a developer, the durability of the image forming apparatus is increased with the use of the toner.
The performance of the developer carrier and the developer layer thickness regulating member may be significantly deteriorated.

Here, the toner having an internal structure refers to, for example, a toner having a core / shell structure having inclusions of different compositions inside, or a multilayer structure having different material layers on the toner surface layer. . Since the toner having such a structure can perform the function separation for each structure,
It is easy to have desired developer properties and can be obtained by various polymerization methods.

According to the study of the present inventors, the toner having such an internal structure loses its rigidity once the structure is damaged by the above-mentioned load and the structure is impaired. It has been found that the fusing easily causes a significant deterioration in the performance of the developing roller 11 and the blade 12.

Accordingly, it is an object of the present invention to prevent a one-component developer having undergone mechanical damage and / or deterioration from remaining and accumulating in a developing device under a load in each rubbing area during image formation. It is an object of the present invention to provide an image forming apparatus, a developing device, and a process cartridge capable of preventing deterioration of a member such as a developer carrier and a developer layer thickness regulating unit and forming a good image over a long period of time. .

Another object of the present invention is to provide a one-component developer having a reduced particle diameter, a low melting point and a low softening point, and a mechanical component even when a one-component developer having an internal structure is used. An image capable of preventing the damaged and / or deteriorated one-component developer from accumulating in the developing device, achieving high image quality, saving energy, and forming a good image over a long period of time. An object of the present invention is to provide a forming device, a developing device, and a process cartridge.

[0032]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
An image carrier on which an electrostatic latent image is formed, and a developing device that develops the electrostatic latent image on the image carrier to form a visible image, wherein the developing device carries and conveys a one-component developer. Supplying the one-component developer to the developer carrier for contacting the one-component developer with the image carrier to develop an electrostatic latent image on the image carrier; and supplying the one-component developer to the developer carrier. Developer supply means for performing, and a developer recovery means for recovering the one-component developer present on the developer carrier through contact with the image carrier from the developer carrier, Forming a developer pool capable of storing the one-component developer recovered from the developer carrier by the developer recovery unit, and housed in the developer pool. The one-component developer is preferentially used to form the electrostatic image on the image carrier. An image forming apparatus characterized by developing the image.

According to another aspect of the present invention, in order to develop an electrostatic latent image on an image carrier into a visible image, a one-component developer is carried and conveyed, and the one-component developer is transferred to the image carrier. A developer carrier for developing an electrostatic latent image on the image carrier in contact with a body, a developer supply unit for supplying the one-component developer to the developer carrier, A developer collecting means for collecting the one-component developer present on the developer carrier through contact with an image carrier from the developer carrier. Forming a developer pool capable of containing the one-component developer recovered from the developer carrier by means;
A developing device is provided, wherein the electrostatic latent image on the image carrier is developed by preferentially using the one-component developer contained in the developer reservoir.

According to another aspect of the present invention, an electrophotographic photosensitive member that is detachably attached to the image forming apparatus main body, carries and transports at least a one-component developer, and transfers the one-component developer. Processing means acting on the electrophotographic photoreceptor including a developer carrier for developing an electrostatic latent image on the electrophotographic photoreceptor in contact with the electrophotographic photoreceptor;
Developing means for supplying the one-component developer to the developer carrier, and developing the one-component developer present on the developer carrier through contact with the electrophotographic photosensitive member; Developer collecting means for collecting from the developer carrier, a developer capable of containing the one-component developer collected from the developer carrier by the developer collecting means. A process cartridge for forming a reservoir and developing the electrostatic latent image on the electrophotographic photosensitive member by preferentially using the one-component developer contained in the developer reservoir; Is done.

According to another aspect of the present invention, there is provided an image forming apparatus in which a process cartridge is detachable and which forms an image on a recording material, comprising: (a) an electrophotographic photosensitive member as an image carrier; Carrying and transporting the component developer,
A process unit acting on the electrophotographic photosensitive member including a developer carrier for contacting the one-component developer with the electrophotographic photosensitive member to develop an electrostatic latent image on the electrophotographic photosensitive member; A developer supply unit for supplying the one-component developer to a developer carrier, and the one-component developer present on the developer carrier through contact with the electrophotographic photoreceptor; Developer collecting means for collecting the developer from the carrier, and a developer reservoir capable of containing the one-component developer collected from the developer carrier by the developer collecting means. And a process cartridge for developing the electrostatic latent image on the electrophotographic photoreceptor by preferentially using the one-component developer contained in the developer reservoir is detachably attached to the apparatus main body. And mounting means for (B) the image forming apparatus characterized by having a conveying means for conveying the recording material is provided.

According to one embodiment of the present invention, a developer accommodating means for accommodating the one-component developer is provided, and the one-component developer in the developer accommodating means is provided with the developer accommodating means. The developer is supplied to the partitioned developer pool.

According to another embodiment of the present invention, the developer reservoir further includes a developer amount detecting means for detecting an amount of the one-component developer in the developer reservoir. The amount of the one-component developer in the developer reservoir is maintained at a predetermined value or less based on the developer amount detection of the developer amount detector. And the one-component developer. Preferably, the developer amount detecting means is selected from a detecting element including a piezoelectric vibrator sensor, a strain gauge, a pressurized conductive sheet and the like. According to one embodiment, the replenishment amount of the one-component developer to the developer reservoir is variably controlled. Preferably, the replenishment amount control of the one-component developer which is variably controlled is performed in multiple steps. Alternatively, it is continuously variable. According to another embodiment, the replenishment amount of the one-component developer to the developer pool is determined by PID control, feedback control, feed forward control, fuzzy control, P
The control is performed by a control method including WM control or control by a combination of these.

According to each of the other embodiments of the present invention, the developer carrier contacts the image carrier.

According to another embodiment of the present invention, the transfer residual toner remaining on the image carrier after the transfer is transferred to the developing portion at the contact portion between the image carrier and the developer carrier. Collect in the reservoir and reuse.

Further, according to each of the preferred embodiments of the present invention, the one-component developer has a shape factor SF-1 of 10%.
0 to 140, and the shape factor SF-2 is 100 to 120, which is substantially spherical. According to another embodiment, a part or the whole of the one-component developer is prepared by a polymerization method. According to another embodiment, a part or all of the one-component developer is formed of a low softening point substance, and the melting point of the low softening point substance is 40 ° C. or more and 90 ° C. or less. According to yet another embodiment, some or all of the one-component developer has an internal structure.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 FIG. 1 shows a schematic configuration of an embodiment of an image forming apparatus according to the present invention. In the present embodiment, the present invention is embodied in an electrophotographic copying machine for forming a black monochrome image, but the present invention is not limited to this.

The copying machine of the present embodiment has
A drum-shaped electrophotographic photosensitive member as an image carrier, that is, a photosensitive drum 101 is supported rotatably in the arrow direction. When the image forming operation starts, the charging means 108 uniformly charges the surface of the photosensitive drum 101. Thereafter, an LED 10 as an exposure unit is provided on the surface of the photosensitive drum 101.
2 performs exposure corresponding to the image information, and the photosensitive drum 101
An electrostatic latent image is formed thereon. According to this embodiment, the charge on the photosensitive drum 101 is negative, and the portion where the charge on the negative electrode is attenuated by the exposure of the LED 102 forms an image portion.

Thereafter, the electrostatic latent image is visualized by the developer supplied from the developing device 103 as the photosensitive drum 101 rotates, so that a so-called toner image is formed on the photosensitive drum 101. In the present embodiment, the development is performed by reversal development, and a developer having the same polarity (negative polarity) as the charged charge adheres to the image portion on the photosensitive drum 101 where the negatively charged charge is attenuated. Further, the developer is supplied to the developing device 103 from a hopper 106 as a developer accommodating unit.

On the other hand, the recording material P accommodated in the cassette 111 is fed into the image forming apparatus by the paper feed roller 112, and is transferred to a transfer area where the photosensitive drum 101 and the transfer roller 104 as transfer means come into contact. Drum 101
The upper toner image is conveyed in synchronization with reaching the transfer area.

Thus, when the toner image on the photosensitive drum 101 and the recording material P reach the transfer area, the toner image is transferred onto the recording material P by the action of the transfer electric field formed in the transfer area by the transfer roller 104. You. After that, the recording material P carrying the unfixed toner image is heated by a fixing unit (heat roller) 105 a provided in the fixing device 105, and pressed by the pressing unit 1.
05b, the unfixed toner image becomes the recording material P
Fixed thereon to form a permanent image.

After the transfer of the toner image has been completed, the photosensitive drum 101 is subjected to removal of transfer residual toner remaining on the surface of the photosensitive drum 101 by a cleaning device 109 having blade-shaped cleaning means, and is ready for a subsequent image forming operation. .

Next, the developing device 103 provided in the copying machine of this embodiment will be further described. FIG. 2 shows a schematic configuration of an embodiment of the developing device 103 according to the present invention and the vicinity thereof.

According to the present embodiment, the developing device 103 includes the developing roller 11 serving as a developer carrier and the photosensitive drum 101.
, And the developing is performed in a state where the developer is in “contact” with the photosensitive drum 101.

The developer used in this embodiment is a negatively chargeable non-magnetic one-component developer (toner). After uniformly dispersing a resin, a release agent containing a low softening point substance, a colorant, and a charge control agent using a pressure kneader, extruder, or media disperser, the toner is mechanically or jetted. A commercially available toner produced by a so-called pulverizing method for producing a toner, comprising the steps of finely pulverizing to a desired particle size by colliding with a target under a stream of air, and further adjusting the particle size to a desired particle size distribution through a classification process. (Crushed toner). The volume average particle diameter of this toner is 8 μm, and additives such as silica are externally added for improving characteristics such as chargeability and fluidity. The additive is not limited to this, as long as it has a function similar to silica,
It can be replaced by another kind of additive.

In the developing device 103, the developing container 16
The developing roller 11 as a developer carrier is supported by the developing container 16 so as to be rotatable in the direction of the arrow so that a part thereof on the side facing the photosensitive drum 101 is open. ing. The developing roller 11 includes an elastic body and is in contact with the photosensitive drum 1 at a predetermined contact pressure. The opening of the developing container 16 is provided with a blowing prevention sheet 1 in order to prevent toner from scattering from the lower portion of the developing roller 11.
5 are provided.

An agitating paddle 14 as a developer agitating and conveying means is provided rotatably in the direction indicated by an arrow at the back of the developing container 16 on the opposite side to the opening. The toner is conveyed to a region (region R) near a contact portion with the supply roller 13 described below.

The supply roller 13 as a developer supply and recovery means is an elastic roller including an elastic body.
1 and are arranged in contact with each other. The toner conveyed to the region R is made uniform in the region R once in a dense state as the supply roller 13 rotates in the direction of the arrow. Thereafter, charge is applied to the toner by frictional charging caused by the rubbing between the developing roller 11 and the supply roller 13 that are counter-rotated and abut on each other. Here, the counter rotation is a rotation in which opposing surfaces (sliding surfaces) advance in opposite directions.

The charged developer is supplied to the developing roller 11 by receiving the reflection force from the developing roller 11 by the charged electric charge. Also, developing container 1
6, a blade 12 as a developer layer pressure regulating member is provided so as to press the developing roller 11, and the layer thickness of the toner supplied on the developing roller 11 is regulated by the blade 12, and Developed roller 1
1 forms a thin layer of toner. Further, at this time, due to the friction between the surfaces of the developing roller 11 and the blade 12, a sufficient charge is applied to the toner for developing.

Thereafter, the thin layer of toner on the developing roller 11 is transferred to the photosensitive drum 101 by the rotation of the developing roller 11.
Area (developing nip) where the roller and the developing roller 11 contact each other
The toner is conveyed to N, and the toner is provided for development while in contact with the photosensitive drum 101. That is, a power supply (not shown) is connected so that a developing electric field is formed between the photosensitive drum 101 and the developing roller 11, and the toner on the developing roller 11 is moved by the action of the developing electric field. The image is transferred to the upper electrostatic latent image, and a so-called toner image is formed on the photosensitive drum 101, and the electrostatic latent image is visualized.

The toner applied to the developing roller 11 and carried and carried to the developing nip N does not contribute to the development, and the toner still carried on the developing roller 11 is slid by the supply roller 13. The developing roller 11 is peeled off from the developing roller 11 by rubbing, and a part thereof is again supplied by the supplying roller 13 together with the toner newly supplied onto the supplying roller 13.
It is supplied upward, and the rest is returned into the developing container 16.
In the present embodiment, the supply roller 13 has two functions as a developer supply and recovery unit. However, the present invention is not limited to this, and the developer supply unit and the developer recovery unit may be combined. It is also possible to provide them separately.

The process speed of the copying machine of this embodiment, that is, the peripheral speed of the photosensitive drum 101 is 150 mm / sec, while the peripheral speed of the developing roller 11 is 225 mm / sec.
sec.

Here, the developing roller 11 has a volume resistivity of 10 ² Ωcm to 10 Ωcm in which a conductive agent such as carbon is dispersed.
It is a semiconductive elastic roller having an outer diameter of 20 mm and made of a low-hardness rubber material or foam such as silicone or urethane of ¹⁰ Ωcm or a combination thereof. Developing roller 1
1, the hardness is 30-45 degrees in JIS-A hardness,
Preferably, a roller having a JIS-A hardness in the range of 30 to 40 degrees is used. In particular, when the developing roller 11 made of a foam is used, a soft roller having an AskerC hardness of 40 degrees or less is used. In addition, the surface of the developing roller 11 has a predetermined surface roughness so as to achieve both the charge imparting property to the toner and the toner transport property. In this embodiment, the surface roughness of the developing roller 11 is JIS B 0
601 has a 10-point average roughness Rz of 5 μm to
10 μm and the maximum height Rmax is 15 μm or less. The surface roughness was measured using a surface roughness tester “SE-30H” (manufactured by Kosaka Laboratory Co., Ltd.).

In this embodiment, the supply roller 13 includes
An insulating sponge roller having an outer diameter of 16 mm was used. The blade 12 is a leaf spring made of SUS having an L-shape, and as shown in FIG. 2, comes into contact with the developing roller 11 at the edge of the L-shape. The material and shape of the developer layer thickness regulating member are not limited to the blade 12 of the present embodiment, but may be of any other type as long as the contact state with the developing roller 11 is reproduced in the same manner as in the present embodiment. It can be replaced with materials and shapes.

In this embodiment, a developer reservoir T for containing the toner collected from the developing roller 11 is formed in the developing container 16 of the developing device 103.

A detecting element 17 is provided in the developing container 16 as a developer amount detecting means.
6, that is, the amount of toner present in the developer pool T is detected. In accordance with the amount of toner detected by the detecting element 17, the toner is supplied from the hopper 106 as a developer accommodating unit to the developing container 16 at any time by an operation based on a sequence described later.
Will be replenished within. The hopper 106 is configured to include the container 21 and a developer replenishing unit 22 that performs agitation of the toner and replenishment of the toner to the developing device 103.

In this embodiment, the detecting element 17 as the developer amount detecting means is a piezoelectric vibrator sensor 17 and is provided at the upper part (17a) and the intermediate part (17b) of the inner wall surface of the developing container 16. Further, it is connected to a signal processing circuit (not shown). The detecting element 17 is not limited to the piezoelectric vibrator, but may be another type of element capable of identifying whether a certain amount of toner is present in the developer pool T, for example, a strain gauge, a pressurized conductive sheet. It is possible to substitute an arbitrary detection element or the like using such a method. Further, it is not limited to the detection element, but may be any means capable of detecting the amount of the developer.

According to the present embodiment, a load is received by a series of rubbing accompanying the image forming operation, and the toner collected in the developing container 16, that is, the developer pool T, is preferentially consumed without contributing to the development. Then, after the amount of toner in the developer pool T decreases, toner is supplied from the hopper 106 as needed. Here, from the viewpoint of increasing the consumption efficiency of the loaded toner, it is desirable to minimize the amount of toner that can be stored in the developer pool T and to the minimum amount that does not hinder image formation. In this embodiment, the amount is required to form 50 single-sided solid A4 size images, so-called solid images.

Next, the operation of detecting the amount of toner and supplying toner will be described in more detail.

The detection of the amount of toner in the developer pool T is performed during a series of operation of the apparatus during image formation. In the present embodiment, the detection element 17 which is a piezoelectric vibrator detects the presence or absence of the developer by detecting the phase difference between the built-in reference vibrator and the vibration of the vibrator facing the detection unit. . That is, when there is a predetermined amount of toner, the vibrator facing the toner is inhibited from vibrating by the toner filled up to the detection unit, and a phase difference is generated from the vibration of the reference vibrator. On the other hand, when the amount of toner falls below a predetermined amount, the vibrator facing the detection surface vibrates in the same phase as the reference vibrator. This phase difference is detected by a signal processing circuit (not shown) to discriminate the presence or absence of the toner. When the presence of toner is detected, the phase difference is turned off, and when the absence of toner is detected, the operation circuit is turned on. (Not shown). In the following description, O
N or 0 or 1 in parentheses after OFF indicates a digital signal.

In the present embodiment, the developer replenishing means 22 has a two-stage replenishing operation mode of a normal replenishing mode for replenishing a fixed amount of toner and a rapid replenishing mode for replenishing a large amount of developer. A detecting element 17a provided at an upper part in the agent reservoir T and a detecting element 17b provided at an intermediate part
The two-stage replenishment mode is controlled by detecting the amount of toner. Hereinafter, the operation of the developer supply means 22 will be described.

That is, the developer supply means 22 operates according to the sequence shown in FIG. Output X of detection element 17a
And the output Y of the detection element 17b is calculated by an arithmetic circuit (not shown).
, And is subjected to digital signal processing. When X and Y are ON at the same time, the rapid replenishment signal N1 is turned ON (1).
Is ON and Y is OFF, the normal replenishment signal N2 is ON (1), and for other combinations of outputs X and Y, both the rapid replenishment signal N1 and the normal replenishment signal N2 are OFF (0). Each of them is inputted, and the ON (1) of the quick replenishment signal N1 and the ON (1) of the normal replenishment signal N2 are outputted to the developer replenishing means 22 according to each case.

When the ON (1) signal of the rapid replenishment signal N1 is input to the developer replenishment means 22, the developer replenishment means 22 starts the rapid replenishment mode operation, and once more toner is discharged than in the normal replenishment mode operation. Will be replenished. This operation is continued until OFF (0) is input to the quick supply signal N1.

As understood from FIG. 3, when the ON (1) signal of the normal replenishment signal N2 is inputted, a value S obtained by integrating this signal by an integrating circuit (not shown) is obtained in advance. When the set specified value St is reached, the operation in the normal supply mode is started, and a fixed amount of toner is supplied. The integral value S is reset every time toner supply is started, and the integral value S becomes zero.

In this embodiment, the toner is supplied to the developer pool T in accordance with the above sequence. However, the present invention is not limited to this.
Control, feedback control, feed forward control,
The toner supply amount can be controlled by fuzzy control, PWM control, or the like, or a combination thereof.

Further, in this embodiment, the toner replenishment by the developer replenishing means 22 is variable in three stages of no replenishment, normal replenishment, and rapid replenishment depending on the replenishment amount. It can be variable.

After performing a durable operation of forming about 20,000 images on an A4 size recording material P in the image forming apparatus of this embodiment, the performance of the developing roller 11 and the blade 12 was examined. The deterioration was within an allowable range, and it was confirmed that a good image could be formed even during the durable operation.

As described above, according to the present invention, since the toner collected from the developing roller 11 by the supply roller 13 is stored, the amount of toner that can be stored is the minimum amount that does not hinder image formation. A certain developer pool T is provided,
Further, since only the amount of toner that compensates for the reduced amount of toner in the developer pool T is replenished at any time, the toner collected in the developer pool T under load due to image formation is efficiently and preferentially consumed again. Can be. Further, since the toner replenishment amount is variably controlled, the amount of toner in the developer pool T can be kept constant even in an operation at a high process speed in which the amount of toner consumption per unit time increases. Was.

Embodiment 2 The image forming apparatus of this embodiment is a copying machine that forms an image with the same configuration and the same operation as Embodiment 1, and differs only in the developer used.

The developer used in the image forming apparatus of this embodiment is designed to save energy by forming an internal structure containing a material having a low softening point.
No. 0231, JP-A-59-53856, JP-A-59-61842, and the like. A component developer (toner) is used. This toner has a so-called core / shell internal structure in which a material having a low softening point is coated with an outer shell resin, and a shell portion in this structure is formed by a polymerization method.

In this embodiment, a compound having a low softening point added to a toner in an amount of 5 to 30% by weight and having a main peak value of 40 to 90 ° C. measured according to ASTM D3418-8 is used. Such compounds are specifically:
Paraffin wax, polyolefin wax, Fischer-Tropsch wax, amide wax, higher fatty acid, ester wax and derivatives thereof, or graft / block compounds thereof can be used.

If the maximum peak value is less than 40 ° C., the self-cohesive force of the low softening point substance becomes weak, and as a result, the high-temperature offset property at the time of fixing to the recording material P becomes unfavorably weak. On the other hand, if the maximum peak value exceeds 90 ° C., the temperature required for fixing increases, and a large amount of heat energy is required, which is not preferable.

In this example, DSC-7 manufactured by Perkin Elemer Co., Ltd. is used for measuring the maximum peak value. For the temperature correction of the device detection unit, the melting points of indium and zinc are used, and for the correction of the calorific value, the heat of fusion of indium is used. As the sample, an aluminum pan was used, and an empty pan was set as a control, and the measurement was performed at a temperature rising rate of 10 ° C./min.

According to the suspension polymerization method at normal temperature or under pressure, spherical fine particles having a particle size of 3 to 8 μm can be obtained relatively easily with a sharp particle size distribution. Thus, uniform development according to the development contrast is performed.

In addition to the suspension polymerization method, a dispersion polymerization method of directly producing a toner using an aqueous organic solvent in which the monomer is soluble and the polymer obtained by polymerization is insoluble, or It is possible to use a toner produced by an emulsion polymerization method typified by a soap-free polymerization method in which a toner is produced by directly polymerizing in the presence of a water-soluble polar polymerization initiator.

In the present embodiment, an additive such as silica is externally added to the above-mentioned toner in order to improve characteristics such as chargeability and fluidity. Other additives, such as aluminum oxide,
Metal oxides such as tin oxide, strontium titanate, zinc oxide, and magnesium oxide; nitrides such as silicon nitride; carbides such as silicon carbide; carbon allotropes such as carbon black and graphite; calcium sulfate, barium sulfate, and calcium carbonate Metal salts and fatty acid metal salts can be substituted.

As described above, when the toner having the internal structure including the core / shell structure is destroyed by the load accompanying the image forming operation, the rigidity of the toner is lost and the developing roller 11 And it becomes easy to fuse to the blade 12 and the like. However, when the toner of the present embodiment is used in the copying machine according to the present invention shown in FIG.
A4 size image formation at 0 mm / sec
After performing the durable operation of about 0 sheets, the performance of the developing roller 11 and the blade 12 was examined. confirmed.

As described above, according to the present invention, it is possible to efficiently and preferentially consume toner that has undergone mechanical damage and / or deterioration under the load associated with image formation. A toner having an internal structure that easily deteriorates can be suitably used.

Embodiment 3 FIG. 4 shows a schematic configuration of another embodiment of the image forming apparatus according to the present invention. According to this embodiment, the image forming apparatus is a laser beam printer that forms an image of a single black color.

The laser beam printer of this embodiment is provided with a drum-shaped electrophotographic photosensitive member as an image carrier, that is, a photosensitive drum 101 rotatably, and a roller-shaped charging means 108 is provided on the photosensitive drum 101. The surface is uniformly charged, and then the surface is exposed to laser light L emitted by the laser exposure system 113, thereby forming an electrostatic latent image according to the image information.

The subsequent image forming process is almost the same as that of the copying machine of the first embodiment. The electrostatic latent image on the photosensitive drum 101 is placed in a developing area (developing nip) N where the photosensitive drum 101 and the developing device 103 are in contact with each other. A so-called toner image is formed on the photosensitive drum 101 by being visualized by the supplied developer. The toner image on the photosensitive drum 101 is then transferred to the cassette 111 under the action of a transfer electric field formed between the photosensitive drum 101 and a transfer roller 104 as a transfer unit.
Is transferred by a paper feed roller 112 and further transferred onto the recording material P transported by a recording material transporting unit 114.

Next, the unfixed toner image on the recording material P is permanently fixed in the fixing device 105 by heat and pressure.
In addition, the transfer residual toner and the like remaining on the photosensitive drum 101 after the transfer is removed by a cleaning device 109 having a blade-shaped cleaning unit, and the photosensitive drum 101 is repeatedly used for image formation.

In the laser beam printer of this embodiment, the photosensitive drum 101, the charging means 108, the cleaning device 109, and the developing device 103 are integrally formed into a cartridge by the frame 115, and the mounting means 116 provided in the main body of the image forming apparatus. The process cartridge 107 is detachable from the main body of the image forming apparatus through the process cartridge 107.

Next, the developing device 103 used in the laser beam printer of this embodiment will be further described.
FIG. 5 shows a schematic configuration of an embodiment of the process cartridge 107 according to the present invention and the vicinity thereof.

In the developing device 103 provided in the process cartridge 107 of this embodiment, as in the first and second embodiments, the developing roller 11 as a developer carrier comes into contact with the photosensitive drum 101, and the developer is transferred to the photosensitive drum 101. Is developed in a state of contact with the substrate.

The developing device 103 of this embodiment uses a non-magnetic one-component developer (toner) as a developer. The developing device 103 includes a developing unit 1 serving as a developer pool T for reversibly developing the electrostatic latent image on the photosensitive drum 101 using toner.
03a and a developer accommodating section 106 as a developer accommodating means.
It is divided into and. That is, this embodiment is an embodiment in which the developing device 103 in the first embodiment and the hopper 106 as the developer accommodating unit are integrally formed.

Here, the toner used as the developer in the present embodiment has a shape factor SF-1 of 100 to 140,
A substantially spherical toner having a shape factor SF-2 in the range of 100 to 120 is used. Such a spherical toner is a negatively chargeable non-magnetic toner having a volume average particle diameter of 7 μm using a toner production method based on a suspension polymerization method, and is subjected to heat treatment for a toner produced by other known pulverization methods. Toner manufactured by Tokubo Sho 56-13945
JP-A-2005-122, a method for obtaining a spherical toner by atomizing a molten mixture into the air using a disk or a fluidized fluid nozzle, or a toner manufactured using various other polymerization methods well known in the art. It is also possible to use.

In this specification, the shape factors SF-1 and SF-2 are FE-SEM (S-80) manufactured by Hitachi, Ltd.
0), 100 toner images are randomly sampled, and the image information is input to an image analyzer (Luzex3) manufactured by Nicole via an interface, analyzed, and calculated by the following equation. Value. That is, SF-1 = (MXLNG) ² / AREA × π / 4 × 10
0 SF-2 = (PERI) ² / AREA × 1 / (4π) ×
Here, as understood from FIG. 9, AREA is the toner projection area, MXLNG is the absolute maximum length of the projected image,
PERI means the circumference of the projected image.

The shape factor SF-1 indicates the degree of sphere, and if it is larger than 140, it gradually departs from sphere and becomes irregular. On the other hand, the shape factor SF-2 indicates the degree of unevenness, and if it is larger than 120, the unevenness on the surface becomes remarkable.

In this embodiment, an additive such as titanium oxide is externally added to the toner in order to improve the characteristics such as chargeability and fluidity. It can be replaced by the additive.

The operation of the developing device 103 according to this embodiment is the same as that of the developing device 10 provided in the image forming apparatus according to the first and second embodiments.
3 is substantially the same as the operation of FIG.

That is, in FIG. 5, a developing roller 1 as a developer carrying member having an outer diameter of 16 mm is provided at an opening of the developing device 103 facing the photosensitive drum 101.
1 is provided rotatably in the direction of the arrow, and supplies toner onto the developing roller 11 by rotating the supply roller 13 in contact with the developing roller 11 in the counter direction with respect to the rotation of the developing roller 11. Next, the toner on the developing roller 11 is electrified by frictional charging while passing through a contact area between the blade 12 and the developing roller 11 as a developer layer thickness regulating means. The developing region (developing nip) N where the drum 101 and the developing roller 11 contact each other is reached. In the developing region N, a developing electric field is formed by a power supply (not shown), and the toner on the developing roller 11 is transferred to the electrostatic latent image on the photosensitive drum 101 by the action of the developing electric field. A toner image is formed.

Further, at the opening of the developing device 103, a blowout prevention sheet 15 for preventing toner scattering from a lower portion of the developing roller 11 is provided. The remaining toner passes through the sheet 15 again, is rubbed by the supply roller 13, is peeled off from the developing roller 11, and is collected in the developer pool T.

As can be understood from the above description, also in the present embodiment, the supply roller 13 serves as a developer supply unit and a developer collection unit.

As described above, all of the space inside the developing section 103a has the same function as that described in Embodiment 1 as the developer pool T, and the developer accommodating section 106 and the developer pool T Are partitioned by a partition W, and the toner is supplied in one direction only from the developer accommodating portion 106 to the developer reservoir T through an opening H provided in the partition W. Therefore, the developer in the developer reservoir T does not return to the developer storage unit 106, and the developer storage unit 106
Is unilaterally consumed.

Here, a stirring paddle 14 as means for stirring and transporting the developer is provided in the developer accommodating section 106 so as to be rotatable in the direction of the arrow, and the developer provided in the developer reservoir T is provided. It is driven based on the detection result of the detection element 17 as an amount detection unit, and agitates the toner and conveys it to the developer pool T. That is, in this embodiment, the stirring paddle also serves as the developer replenishing means 22 described in the first embodiment.

Also in this embodiment, in order to efficiently use the toner collected again under the load, the amount of developer that can be stored in the developer pool T is the minimum amount that does not hinder image formation. In this embodiment, an amount corresponding to the amount of toner consumption required for forming 30 one-sided solid A4 size images can be accommodated.
In the present embodiment, the detecting element 17 provided in the developer reservoir T as a developer amount detecting means is a pressurized conductive sheet.

The process speed (corresponding to the peripheral speed of the photosensitive drum 101) of the laser beam printer of this embodiment is 120 mm / sec, and the peripheral speed of the developing roller 11 is 200 mm / sec.

Next, the control of toner supply according to this embodiment will be described in detail.

The detection of the amount of toner in the developer pool T is performed during the above-described series of image forming operations. The pressurized conductive sheet as the detection element 17 is a pressure sensor utilizing the fact that the conductive elastomer inside is elastically deformed by pressurization and the contact resistance fluctuates. That is, when there is a predetermined amount of toner, the pressurized conductive sheet is pressurized by the toner filled up to the detection unit. However, when the amount of developer falls below the predetermined amount, the pressure on this sheet is reduced. , The resistance fluctuates. This resistance fluctuation is processed by a processing circuit (not shown).
And a replenishment signal of OFF (0) is output when the predetermined amount of toner is present, and ON (1) when the predetermined amount is not present.

To supply the toner from the developer container 106 to the developer pool T, the detection element 17 outputs ON.
/ OFF is controlled based on the replenishment signal, and the stirring paddle 14 is controlled.
Is executed by the operation. That is, as shown in FIG. 6, when the detection element outputs the replenishment signal OFF (0), the operation of the stirring paddle 14 is stopped, and the toner is not replenished. On the other hand, when ON (1) of the replenishment signal is output, the stirring paddle 14 rotates at a predetermined speed and supplies a fixed amount of toner to the developing unit 103a. Therefore, only the amount that compensates for the amount of toner reduction in the developer pool T is supplied at any time.

As described above, the present invention is also applicable to a process cartridge that can be attached to and detached from the image forming apparatus main body, and similarly to the first and second embodiments, preferentially consumes the loaded toner. This has the effect of prolonging the life of members such as the developing roller 11 and the blade 12, and allows the user to perform maintenance of the image forming apparatus by himself, thereby improving operability.

Further, in the present embodiment, the laser beam printer is driven at a process speed of 120 mm / sec to perform an endurance operation of about 20,000 sheets of A4 size image formation. The performance of the member and the evaluation of the image were performed. Further, in order to clarify the operation and effect of the present invention, as a comparative example, a toner produced by the same polymerization method as in this example and having different shape factors SF-1 and SF-2 as shown in Table 1 was used. The same durable operation was performed in the case of performing the same, and the same evaluation was performed. That is, in Comparative Example A, the degree of unevenness of the toner surface indicated by the shape factor SF-2 is larger than that in the example.
Further, in Comparative Example B, the spherical degree of the toner indicated by the shape factor SF-1 is smaller than that of Example and is irregular.
Table 2 shows the results.

When the performance deterioration of the developing roller 11 and the blade 12 is within the allowable range, the mark is indicated by “○”.

[0110]

[Table 1]

[0111]

[Table 2]

As can be understood from the results shown in Table 2, the use of a spherical toner having a rigid shape, which is hardly subjected to the load associated with image formation, as a developer reduces toner damage itself. The effect of the present invention for preventing the deterioration of the image and the performance of the developing roller 11 and the blade 12 can be further enhanced.

Embodiment 4 FIG. 7 shows a schematic configuration of another embodiment of the image forming apparatus according to the present invention. According to this embodiment, the image forming apparatus is a cleaner-less laser beam printer. That is, no special cleaning device is provided for removing transfer residual toner and the like remaining on the surface of the photosensitive drum 1 after the transfer is completed.

Further, in this embodiment, the photosensitive drum 101, the charging means 108 and the developing device 103 are integrally formed into a cartridge by the frame 115, and the image forming apparatus is mounted via the mounting means 116 provided in the main body of the image forming apparatus. The process cartridge is detachable from the main body.

FIG. 8 shows a schematic structure of another embodiment of the process cartridge according to the present invention and the vicinity thereof.

In the laser beam printer of this embodiment, the charging means 108 charges the photosensitive drum 101 to a ground voltage of -650 V, and the laser exposure system 102 exposes the electrostatic latent image having a potential of -150 V to the ground voltage. An image is formed on the photosensitive drum 101. This electrostatic latent image is developed in a state in which the electrostatic latent image is in contact with the toner applied on the developing roller 11 of the developing device 103 to become a toner image. A developing electric field is formed between the photosensitive drum 101 and the developing roller 11, and the ground voltage of the developing roller 11 at this time is -350V. Therefore, under the action of the developing electric field formed by these potential differences, the toner applied on the developing roller is transferred to the electrostatic latent image held on the photosensitive drum, thereby performing the development.

In this embodiment, the process speed, that is, the peripheral speed of the photosensitive drum is 150 mm / sec, and the peripheral speed of the developing roller 11 is 200 mm / sec.

Thereafter, the toner image on the photosensitive drum 101 is electrostatically transferred onto the recording material P by the action of a transfer electric field formed between the transfer roller 104 and the photosensitive drum 101. The upper unfixed toner image is permanently fixed by the fixing device 105 by heat and pressure.

As can be understood from FIG. 8, the developing device 103 provided in the process cartridge of this embodiment has the same configuration as that of the developing device 103 of the third embodiment, and the developer is the same as that of the third embodiment. Was used.

In this embodiment, the history of the previous image formation remaining on the photosensitive drum 101, that is, the so-called untransferred toner is removed by the mechanical action due to the rubbing of the developing roller 11 and the photosensitive drum 101 and the developing electric field. The toner is collected from the surface of the photosensitive drum 101 onto the developing roller 11 by an electric action.

That is, in the laser beam printer of the present embodiment, the transfer efficiency when the toner image formed on the photosensitive drum 101 is transferred onto the recording material P is 85 to 95%.
Generally, the transfer residual toner that has not been transferred remains on the photosensitive drum 101 as a history. Therefore, in the subsequent image formation, the transfer residual toner reaches the contact portion between the developing roller 11 and the photosensitive drum 101 again.

According to the present embodiment, the transfer residual toner is charged to the negative polarity of the same polarity as the surface of the photosensitive drum 101 by the charging means 108 which passes before reaching the contact portion with the developing roller 11 again. . Therefore, the toner adhered to the image portion of the electrostatic latent image formed by the exposure continues to be carried on the photosensitive drum 101, and the toner is supplied together with the toner newly supplied at the contact portion with the developing roller 11. Form an image. On the other hand, the transfer residual toner adhering to the non-image portion is collected on the developing roller 11 by a developing electric field formed between the developing roller 11 and the photosensitive drum 101.
At the same time, at the contact portion between the photosensitive drum 101 and the developing roller 11, the developing roller 11 is rotated at a higher peripheral speed than the peripheral speed of the photosensitive drum 101, so that the mechanical scraping by the rubbing is performed. The transfer residual toner is also collected on the developing roller 11.

Further, the transfer residual toner collected on the developing roller 11 and the toner supplied to the developing roller 11 but not contributing to the development are peeled off from the developing roller 11 by the rubbing of the supply roller 13. In the developing section 103a,
That is, the developer is stored in the developer pool T.

In this embodiment, similarly to the third embodiment, the stirring paddle 1 serving also as the developer replenishing means is based on the detection result of the toner amount by the detecting element 17 as the developer amount detecting means.
4 replenishes the toner from the developer accommodating portion 106 to the developer pool T at any time only with an amount that supplements the reduced amount of toner.

By driving the laser beam printer of this embodiment at a process speed of 120 mm / sec, the A4
When an image of the size was subjected to a durable operation of about 10000 sheets and deterioration of members such as the developing roller 11 and the blade 12 was evaluated, the deterioration was within an allowable range, and the image during the durable operation was good.

As described above, according to the present invention, in a cleanerless image forming apparatus, even when the transfer residual toner containing a large amount of toner that has been mechanically damaged and / or deteriorated during image formation is reused, Since the loaded toner can be efficiently and preferentially consumed, deterioration of members such as the developing roller 11 and the blade 12 can be prevented for a long time.

In the third and fourth embodiments, for example, the amount of toner supplied is variably controlled by the developer amount detecting means in the same manner as in the first embodiment, so that the toner consumption is increased at a high process speed. It is possible to cope with the image forming operation, and it is also possible to adopt another control method described in the first embodiment.

Further, in each of Examples 1 to 4, the description has been made assuming that a non-magnetic one-component toner is used as a developer. However, the present invention is not limited to this. A similar effect can be obtained.

Further, in the first to fourth embodiments, the supply roller 13 has been described as serving both as a developer supply unit and a developer collection unit. However, separate members may be provided by separating their functions. It is.

[0130]

As described above, according to the present invention,
An image carrier on which an electrostatic latent image is formed; and a developing device that develops the electrostatic latent image on the image carrier to produce a visible image. A developer carrier for contacting the component developer with the image carrier to develop an electrostatic latent image on the image carrier, and a developer supply unit for supplying a one-component developer to the developer carrier And a developer collecting means for collecting a one-component developer present on the developer carrier through contact with the image carrier from the developer carrier. Forming a developer pool capable of containing the one-component developer recovered from the developer carrier, and preferentially using the one-component developer contained in the developer reservoir on the image carrier. The electrostatic latent image of the developer is developed, so that the developer is stored again due to the load The recovered single component developer becomes efficient preferentially can be consumed.

Therefore, according to the image forming apparatus of the present invention, the developing device used in the image forming apparatus, and the process cartridge detachably attached to the image forming apparatus, a load is imposed upon the image forming. To prevent the one-component developer, which has been mechanically damaged and / or degraded, from remaining and accumulating in the developing device, thereby preventing the deterioration of members such as the developer carrier and the developer layer thickness regulating means for a long time. Thus, a good image can be formed.

[Brief description of the drawings]

FIG. 1 shows a schematic configuration of an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram showing one embodiment of a developing device according to the present invention and its vicinity.

FIG. 3 is a diagram for explaining an embodiment of toner supply control according to the present invention.

FIG. 4 is a schematic configuration diagram showing another embodiment of the image forming apparatus according to the present invention.

FIG. 5 is a schematic configuration diagram showing one embodiment of a process cartridge according to the present invention and its vicinity.

FIG. 6 is a diagram for explaining another embodiment of the toner supply control according to the present invention.

FIG. 7 is a schematic configuration diagram showing another embodiment of the image forming apparatus according to the present invention.

FIG. 8 is a schematic configuration diagram showing another embodiment of the process cartridge according to the present invention and its vicinity.

FIG. 9 is a diagram for explaining shape factors SF-1 and SF-2.

FIG. 10 is a schematic configuration diagram illustrating an example of a conventional image forming apparatus.

FIG. 11 is a schematic configuration diagram showing an example of a conventional developing device and its vicinity.

[Explanation of symbols]

Reference Signs List 11 developing roller (developer carrier) 12 blade (developer layer thickness regulating member) 13 supply roller (developer supply and recovery means) 14 stirring paddle 17 detecting element (developer amount detecting means) 22 developer replenishing means 101 photosensitive Drum (electrophotographic photoreceptor, image carrier) 102 LED (exposure unit) 103 developing device 104 transfer roller (transfer unit) 105 fixing device 106 developer storing unit (hopper, developer developer storing unit) 107 process cartridge 108 charging Means 109 Cleaning Device T Developer Pool

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Katsuhiro Sakaizawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H005 AA06 AA11 AA15 AB06 CA14 DA07 EA03 FA07 2H027 DA01 DD02 DE03 EA06 HB13 HB15 2H077 AA15 AB03 AC16 AD06 AD13 AD23 AD31 AE03 BA08 BA09 CA12 DA15 DA42 DA75 DA78 DB10 EA14 EA15 FA01 FA25 FA27 GA04

Claims (56)

[Claims] An image carrier on which an electrostatic latent image is formed, and a developing device that develops the electrostatic latent image on the image carrier into a visible image, wherein the developing device is a one-component developing device. A developer carrying member for carrying and transporting the developer and bringing the one-component developer into contact with the image carrying member to develop an electrostatic latent image on the image carrying member; A developer supply unit for supplying a component developer, and a developing device for collecting the one-component developer present on the developer carrier through the contact with the image carrier from the developer carrier. Agent recovery means;
Forming a developer pool capable of storing the one-component developer recovered from the developer carrier by the developer recovery unit, and housed in the developer pool. An image forming apparatus, wherein the electrostatic latent image on the image carrier is developed by preferentially using the one-component developer. 2. A developer accommodating means for accommodating the one-component developer, wherein the one-component developer in the developer accommodating means is transferred to the developer reservoir separated from the developer accommodating means. 2. The image forming apparatus according to claim 1, wherein replenishment is performed. 3. The apparatus according to claim 1, further comprising: a developer amount detecting unit for detecting an amount of the one-component developer in the developer reservoir in the developer reservoir, wherein the developer amount detecting unit detects the amount of the developer. Supplying the one-component developer from the developer accommodating means to the developer reservoir so as to maintain the amount of the one-component developer in the developer reservoir based on a predetermined value or less. The image forming apparatus according to claim 2, wherein: 4. The image forming apparatus according to claim 3, wherein said developer amount detecting means is selected from a detecting element including a piezoelectric vibrator sensor, a strain gauge, a pressurized conductive sheet and the like. 5. The image forming apparatus according to claim 2, wherein the replenishment amount of the one-component developer to the developer pool is variably controlled. 6. The image forming apparatus according to claim 5, wherein the variable amount control of the supply amount of the one-component developer is variable in multiple steps or continuously. 7. A replenishing amount of the one-component developer to the developer reservoir is controlled by a control method including PID control, feedback control, feedforward control, fuzzy control, PWM control, or control by a combination thereof. The image forming apparatus according to claim 2, 3 or 4, wherein: 8. The image forming apparatus according to claim 1, wherein said developer bearing member is in contact with said image bearing member. 9. The method according to claim 1, wherein the transfer residual toner remaining on the image carrier after the transfer is collected in the developer reservoir at a contact portion between the image carrier and the developer carrier and reused. The image forming apparatus according to any one of claims 1 to 8, wherein: 10. The one-component developer has a shape factor SF-
1 is 100 to 140, shape factor SF-2 is 100 to 12
The image forming apparatus according to claim 1, wherein the image forming apparatus has a substantially spherical shape. 11. The method according to claim 1, wherein a part or the whole of the one-component developer is produced by a polymerization method.
0. The image forming apparatus according to claim 1, wherein 12. A part or all of the one-component developer is formed of a low softening point substance, and the melting point of the low softening point substance is 4%.
The temperature is between 0 ° C and 90 ° C.
To 11 image forming apparatuses. 13. An image forming apparatus according to claim 1, wherein a part or all of said one-component developer has an internal structure. 14. A method for developing a latent image by developing an electrostatic latent image on an image carrier, carrying and transporting a one-component developer and bringing the one-component developer into contact with the image carrier to form the image. A developer carrier for developing the electrostatic latent image on the carrier, a developer supply unit for supplying the one-component developer to the developer carrier, and contacting the image carrier. A developer collecting means for collecting the one-component developer present on the developer carrier through the developer carrier via the developer carrier. Forming a developer reservoir capable of containing the one-component developer recovered from the developer carrier, and preferentially using the one-component developer contained in the developer reservoir on the image carrier. A developing device for developing the electrostatic latent image. 15. A developer accommodating means for accommodating the one-component developer, wherein the one-component developer in the developer accommodating means is transferred to the developer reservoir partitioned from the developer accommodating means. 15. The developing device according to claim 14, wherein replenishment is performed. 16. A developer amount detecting means for detecting an amount of the one-component developer in the developer reservoir in the developer reservoir, wherein the developer amount detecting means detects the amount of the developer. In order to maintain the amount of the one-component developer in the developer pool based on a predetermined value or less,
The developing device according to claim 15, wherein the one-component developer is supplied from the developer storage unit to the developer pool. 17. The developing apparatus according to claim 16, wherein said developer amount detecting means is selected from a detecting element including a piezoelectric vibrator sensor, a strain gauge, a pressurized conductive sheet, and the like. 18. The developing device according to claim 15, wherein a replenishing amount of said one-component developer to said developer pool is variably controlled. 19. The developing apparatus according to claim 18, wherein the variable amount control of the supply amount of the one-component developer is variable in multiple steps or continuously. 20. A replenishing amount of the one-component developer to the developer pool is controlled by a control method including PID control, feedback control, feedforward control, fuzzy control, PWM control, or control by a combination thereof. The developing device according to claim 15, 16 or 17, wherein 21. The developing device according to claim 14, wherein said developer carrier comes into contact with said image carrier. 22. A transfer portion of a transfer residual toner remaining on the image carrier after transferring a visible image formed on the image carrier onto a recording material, the contact portion between the image carrier and the developer carrier. 22. The developing device according to claim 14, wherein the developer is collected in the developer reservoir and reused. 23. The one-component developer has a shape factor SF-
1 is 100 to 140, shape factor SF-2 is 100 to 12
23. The developing device according to claim 14, wherein the developing device is substantially spherical. 24. The method according to claim 14, wherein a part or the whole of the one-component developer is produced by a polymerization method.
24. The developing device according to any one of 23. 25. A part or all of the one-component developer is formed of a low softening point substance, and the melting point of the low softening point substance is 4%.
The temperature is between 0 ° C and 90 ° C.
The developing device according to any one of Items 4 to 24. 26. The developing device according to claim 14, wherein a part or all of the one-component developer has an internal structure. 27. The image forming apparatus is detachable from a main body of the image forming apparatus.
An electrophotographic photosensitive member as an image carrier and at least a one-component developer are carried and transported, and the one-component developer is brought into contact with the electrophotographic photosensitive member to develop an electrostatic latent image on the electrophotographic photosensitive member. A process unit acting on the electrophotographic photoreceptor including a developer carrier for performing, a developer supply unit for supplying the one-component developer to the developer carrier, and the electrophotographic photoreceptor. A developer collecting means for collecting the one-component developer present on the developer carrying member from the developer carrying member through contact with the developer carrying member. Forming a developer pool capable of storing the one-component developer recovered from the developer carrier, and preferentially using the one-component developer stored in the developer pool to generate the electrophotographic image. Photoconductor A process cartridge, wherein the developing of the electrostatic latent image. 28. A developer accommodating means for accommodating the one-component developer, wherein the one-component developer in the developer accommodating means is transferred to the developer reservoir partitioned from the developer accommodating means. 28. The process cartridge according to claim 27, wherein replenishment is performed. 29. The apparatus according to claim 29, further comprising: a developer amount detecting unit for detecting an amount of said one-component developer in said developer reservoir in said developer reservoir, wherein said developer amount detecting unit detects said developer amount. In order to maintain the amount of the one-component developer in the developer pool based on a predetermined value or less,
29. The process cartridge according to claim 28, wherein the one-component developer is supplied from the developer accommodating unit to the developer reservoir. 30. The process cartridge according to claim 29, wherein said developer amount detecting means is selected from a detecting element including a piezoelectric vibrator sensor, a strain gauge, a pressurized conductive sheet and the like. 31. The process cartridge according to claim 28, wherein the replenishment amount of the one-component developer to the developer reservoir is variably controlled. 32. The process cartridge according to claim 31, wherein the variable amount control of the supply amount of the one-component developer is variable in multiple steps or continuously. 33. A replenishment amount of the one-component developer to the developer reservoir is controlled by a control method including PID control, feedback control, feedforward control, fuzzy control, PWM control, or control by a combination thereof. 31. The process cartridge according to claim 28, 29, or 30, wherein: 34. The process cartridge according to claim 27, wherein the developer carrier contacts the electrophotographic photosensitive member. 35. A transfer residual toner remaining on the electrophotographic photosensitive member after the transfer is recovered and reused in the developer reservoir at a contact portion between the electrophotographic photosensitive member and the developer carrier. The process cartridge according to any one of claims 27 to 34, wherein: 36. The one-component developer has a shape factor SF-
1 is 100 to 140, shape factor SF-2 is 100 to 12
The process cartridge according to any one of claims 27 to 35, wherein the process cartridge is 0 and has a substantially spherical shape. 37. A method according to claim 27, wherein a part or the whole of said one-component developer is produced by a polymerization method.
36. The process cartridge according to any one of the items 36. 38. A part or all of the one-component developer is formed of a low softening point substance, and the melting point of the low softening point substance is 4%.
3. The temperature is not lower than 0 ° C. and not higher than 90 ° C.
38. The process cartridge according to any one of items 7 to 37. 39. The process cartridge according to claim 27, wherein a part or all of the one-component developer has an internal structure. 40. The process cartridge is configured such that the developer carrier, the charging unit or the cleaning unit as the process unit, and the electrophotographic photosensitive member are integrally formed into a cartridge, and is detachably mountable to an image forming apparatus main body. The process cartridge according to any one of claims 27 to 39, wherein: 41. The process cartridge is such that the developer carrying member as the process means, the charging means, the cleaning means, and the electrophotographic photosensitive member are integrally formed into a cartridge and can be attached to and detached from the image forming apparatus main body. The process cartridge according to any one of claims 27 to 39, wherein: 42. An image forming apparatus in which a process cartridge is detachable and which forms an image on a recording material,
(A) An electrophotographic photosensitive member as an image carrier, and at least a one-component developer are carried and transported, and the one-component developer is brought into contact with the electrophotographic photosensitive member to form an electrostatic latent image on the electrophotographic photosensitive member. Processing means for acting on the electrophotographic photoreceptor including a developer carrier for developing an image, developer supply means for supplying the one-component developer to the developer carrier, and the electrophotography Developer collecting means for collecting the one-component developer present on the developer carrier through contact with a photoreceptor from the developer carrier, and the developer collecting means Forming a developer reservoir capable of containing the one-component developer recovered from the developer carrier, and preferentially using the one-component developer contained in the developer reservoir. The electrostatic latent image on the electrophotographic photosensitive member And mounting means for mounting detachably a process cartridge that image to the apparatus main body,
(B) an image forming apparatus, comprising: a conveying unit configured to convey the recording material. 43. A developer accommodating means for accommodating the one-component developer, wherein the one-component developer in the developer accommodating means is transferred to the developer reservoir partitioned from the developer accommodating means. The image forming apparatus according to claim 42, wherein replenishment is performed. 44. The apparatus according to claim 44, further comprising: a developer amount detector for detecting an amount of said one-component developer in said developer reservoir in said developer reservoir, wherein said developer amount detector detects developer amount. In order to maintain the amount of the one-component developer in the developer pool based on a predetermined value or less,
44. The image forming apparatus according to claim 43, wherein the one-component developer is supplied from the developer accommodating unit to the developer reservoir. 45. The image forming apparatus according to claim 44, wherein said developer amount detecting means is selected from a detecting element including a piezoelectric vibrator sensor, a strain gauge, a pressurized conductive sheet and the like. 46. The image forming apparatus according to claim 43, wherein an amount of the one-component developer supplied to the developer reservoir is variably controlled. 47. The image forming apparatus according to claim 46, wherein the variable amount control of the replenishment amount of the one-component developer is variable in multiple stages or continuously. 48. The replenishment amount of the one-component developer to the developer reservoir is controlled by a control method including PID control, feedback control, feedforward control, fuzzy control, PWM control, or control by a combination thereof. 46. The image forming apparatus according to claim 43, wherein the image forming apparatus comprises: 49. The image forming apparatus according to claim 42, wherein the developer carrier contacts the electrophotographic photosensitive member. 50. A transfer residual toner remaining on the electrophotographic photosensitive member after transfer is collected in the developer reservoir at a contact portion between the electrophotographic photosensitive member and the developer carrying member and is reused. The image forming apparatus according to any one of claims 42 to 49, wherein: 51. The one-component developer, wherein the shape factor SF-
1 is 100 to 140, shape factor SF-2 is 100 to 12
The image forming apparatus according to any one of claims 42 to 50, wherein the image forming apparatus has a substantially spherical shape. 52. The method according to claim 42, wherein a part or the whole of the one-component developer is produced by a polymerization method.
51. The image forming apparatus according to any one of items 51. 53. A part or all of the one-component developer is formed of a low softening point substance, and the melting point of the low softening point substance is 4%.
The temperature is not lower than 0 ° C and not higher than 90 ° C.
The image forming apparatus according to any one of Items 2 to 52. 54. The image forming apparatus according to claim 42, wherein a part or all of the one-component developer has an internal structure. 55. The process cartridge is configured such that the developer carrying member as a process unit, a charging unit or a cleaning unit, and the electrophotographic photoreceptor are integrally formed into a cartridge, and is detachably mountable to an image forming apparatus main body. The image forming apparatus according to any one of claims 42 to 54, wherein: 56. The process cartridge, wherein the developer carrier as a process unit, a charging unit, a cleaning unit, and an electrophotographic photosensitive member are integrally formed into a cartridge and can be attached to and detached from an image forming apparatus main body. The image forming apparatus according to any one of claims 42 to 54, wherein: