JPH04310986A - One-component developing device - Google Patents

Abstract

PURPOSE:To obtain a one-component developing device having less reduction in an image density and always carrying out the development of an uniform image density even if the development is repeated many times. CONSTITUTION:In a developer stirring room 5 supplying a developer to a developer carrier 3, the developer is not carried in the axial direction of the developer carrier 3. A developer carrying room 7 is provided differential from the developer stirring room 5, and the developer is carried so as to uniformly distribute the developer in the axial direction of the developer carrier 3, in the developer carrier 7. Further, an uniform supplying mechanism 10 which can uniformly supply the developer in the axial direction of the developer carrier of the developer stirring room 5 from the developer carrying room 7, is provided. Thus, a load is received by a developer regulating member 4, and the developer reduced in an electrostatic charge quantity is prevented from being diasedly heaped on end part of the axial direction of a formed image.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a developing device that is used in image forming apparatuses such as electrophotographic copying machines and printers, and which attaches a developer to an electrostatic latent image to make it visible. The present invention relates to a developing device that is used to perform development.

0002

2. Description of the Related Art As a developing device using a developer, for example, the one shown in FIG. 7 has been known. In this developing device, a plurality of magnets are fixedly arranged in a rotatable cylindrical sleeve. A developer regulating member 104 that is arranged so as to be in pressure contact and regulates the developer adsorbed on the surface of the developer carrier and thins the developer is housed in the housing 101 .

The housing 1 is open at the front side where the developer carrier 103 faces the electrostatic latent image holder 102.
A stirring chamber 105 for transporting the developer T along the developer carrier 103 and stirring it is formed at the rear. In the stirring chamber 105, a developer transporting and supplying member 106 is provided which is arranged parallel to the developer carrier 103 and transports and supplies the developer while rotating and stirring. Further, one end of the stirring chamber 105 along the axial direction of the developer carrier 103 is shown in FIG.
As shown in FIG. A developer supply box 116 is provided at the upper part of this developer carrying-in passage 115, and a necessary amount of developer T is supplied to the developer carrying-in passage 115 as appropriate.
It is designed to be replenished by dropping it within 15 minutes.

[0004] In such a developing device, the stirring chamber 10
The developer T supplied into the developer transporting and supplying member 10
6 gradually conveys it toward the other end of the stirring chamber 105. At the same time, the developer is supplied to the developer carrier 103 and the developer adsorbed on its surface is made into a thin layer by the developer regulating member 104, and the developer carrier 103 is transferred to the development area facing the electrostatic latent image carrier 102. and is transported. The developer that did not contribute to development is carried into the housing 101 again as the developer carrier 103 rotates, and is peeled off from the developer carrier 103.

[0005]

However, such a developing device has the following problems. Along with conveying the developer T in the axial direction of the developer carrier as described above,
When the developer is adsorbed to the surface of the developer carrier and repeatedly conveyed to the development area and peeled off, the developer carried into the stirring chamber 105 is gradually rubbed against the developer regulating member 104 and gradually transferred to the conveying and supplying member. 106 in the transport direction. For this reason, the developer near the other end, that is, the end in the transport direction, is subjected to a greater load than the developer on the side where the developer supply box 116 of the stirring chamber 105 is attached. A phenomenon has occurred in which external additives (such as silica) added to the developer to adjust the amount of charge sink into the toner or separate from the toner. On the front end side in the transport direction where a large amount of developer with such an abnormality has accumulated, the amount of charge of the developer is lower than that on the side where the developer supply box 116 is located, and the density of the developed recorded image may decrease. arise. This causes density unevenness within the width of the image, making it impossible to obtain a good image.

[0006] This problem is not unique to the type of developing device that presses the developer to form a thin layer using a developer regulating member (blade) that is pressed against the developer carrier; for example, As shown in FIG. 9, even in a type of developing device in which a thin layer of developer is formed by a trimming member 117 that is not in contact with the developer carrier, a load is applied to the developer due to trimming, and the above-mentioned problem occurs. arise.

The present invention has been made in view of the above-mentioned problems, and its purpose is to supply developer almost uniformly to the developer carrier in its axial direction, and to perform multiple development cycles. It is an object of the present invention to provide a one-component developing device which is capable of always performing development with uniform image density and with little reduction in image density even after repeated use.

[0008]

[Means for Solving the Problems] In order to solve these problems, the present invention provides a developer carrier which is disposed opposite to an electrostatic latent image carrier and conveys a one-component developer by adhering it to the surface. a developer regulating member that regulates the amount of developer attached to the developer carrier, and a developer regulating member that is provided along the axial direction of the developer carrier and that stirs the developer and that is arranged in the axial direction of the developer carrier. In a one-component developing device having a developer stirring chamber capable of supplying developer over almost the entire length of the developer carrier, the one-component developing device is provided over almost the entire length of the developer carrier and is provided almost parallel to the axial direction of the developer carrier, A developer transport chamber that can temporarily store the developer separately from the developer stored in the developer stirring chamber; a developer supply section that supplies developer to the developer transport chamber; and a developer supply section that supplies developer to the developer transport chamber. A developer transport device transports the stored developer so that it is evenly distributed in the axial direction of the developer carrier, and a developer stirring device transports the developer that is almost evenly distributed in the developer transport chamber. The developer is provided with an even supply mechanism that supplies developer almost evenly in the axial direction of the developer carrier in the chamber.

The developer transport chamber is provided, for example, at the top of the developer stirring chamber, and the developer uniform supply mechanism is provided at the bottom of the developer transport chamber and extends over almost the entire length of the developer carrier in the axial direction. It can be an opening/closing member that can open the bottom. Further, the developer transporting chamber is constructed by disposing a uniform cross-sectional member having a concave portion with an open upper part in the axial direction of the developer carrier above the developer stirring chamber, and the uniform developer supplying mechanism is configured such that the uniform cross-sectional member has a recess with an open top. It is also possible to adopt a mechanism in which the developer is rotated around its axis and the developer is discharged from the opening at the top into the developer stirring chamber. The developer transport device that transports the developer in the developer transport chamber is one that has screw-like projecting wings, or one that has a spiral transport member attached to a rod-shaped member arranged in the axial direction of the developer carrier. There can be various configurations that allow for axial transport.

0010

[Operation] In the one-component developing device configured as described above, the developer is supplied from the developer supply section to the developer transport chamber, and since the developer transport device is provided in the developer transport chamber, the developer is The developer is transported and distributed evenly in the axial direction of the developer carrier. Furthermore, since the developer transport chamber has an even supply mechanism, the developer evenly distributed within the developer transport chamber is evenly supplied in the axial direction of the developer carrier in the developer stirring chamber. In the developer stirring chamber, the developer is stirred and supplied to the developer carrier, but the developer is not conveyed in the axial direction of the developer carrier, and is supplied evenly, so that the developer is always almost constant in the developer stirring chamber. Evenly distributed developer.

The developer supplied to the developer carrier is regulated by the developer regulating member and subjected to a load, but the loaded developer is evenly distributed in the axial direction of the developer carrier, There is no possibility that the concentration of the developer in which the external additive has abnormality becomes high in some parts due to the load. Therefore, the image density does not decrease in a portion in the axial direction of the developer carrier, and the overall image density decreases less.

0012

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. 1, 2, and 3 are diagrams showing the configuration of a one-component developing device that is a first embodiment of the present invention, FIG. 1 is a partially see-through schematic perspective view, and FIG. 2 is shown in FIG. 3 is a schematic sectional view taken along the line II--II, and FIG. 3 is a schematic sectional view taken along the line II-II shown in FIG. This developing device includes a housing 1 having an opening facing an electrostatic latent image holder 2;
A developer carrying member 3 provided inside to face the electrostatic latent image holding member 2, a developer regulating member 4 for regulating the amount of developer adhered on the developer carrying member 3, and a developer carrying member 3. The developer stirring chamber 5 has a developer stirring chamber 5 in which the developer supplied to the developer 3 is stored while being stirred, and a developer conveying chamber 7 which is separated from the developer stirring chamber 5 above the developer stirring chamber.

The developer carrier 3 is provided with a rotatable cylindrical sleeve around the outer periphery of a fixedly supported, substantially cylindrical magnet roll 13.
3 is provided with an S pole and an N pole along its circumference. The arrangement of these magnetic poles is such that a magnetic field that attracts the developer is formed along the surface of the cylindrical sleeve, so that the developer can be attracted to the surface of the developer carrier 3 and transported. There is. The developer regulating member 4 includes a soft elastic member 4a that is pressed against the surface of the developer carrier 3 and an elastic member 4b that supports this near one end, and the other end of the elastic member 4b is fixed to the housing 1. .

The developer agitation chamber 5 is provided along almost the entire length of the developer carrier 3 in the axial direction, and has a developer agitation supply member 6 that agitates the developer and supplies the developer to the developer carrier 3. We are prepared. The developer agitation and supply member 6 has a rotating shaft parallel to the axial direction of the developer carrier, and the additional member 6a attached to this rotating shaft rotates to agitate the developer and transfer it to the developer carrier 3. supply Further, a toner sensor 12 is attached to the wall of the developer stirring chamber 5, so that the remaining amount of developer in the developer stirring chamber 5 can be detected.

The developer transport chamber 7 transports the developer into the developer stirring chamber 5.
The developer stirring chamber 5 is provided in parallel with the axial direction of the developer carrier 3 in approximately the same range as the developer stirring chamber 5 . Further, a developer supply section 9 is connected to one end of the developer transport chamber 7, and a supply valve 9b is operated based on a signal detected by a toner sensor 12 provided in the developer stirring chamber 5, and the developer is supplied from the hopper 9a. is supplied into the developer transport chamber 7. A developer transporting member 8 (hereinafter referred to as auger) that has spiral-shaped projecting wings and is rotatably supported is provided inside the developer transporting chamber 7 . The developer supplied therein can be transported so as to be evenly distributed in the length direction of the developer transport chamber 7. The bottom of the developer transport chamber has an opening/closing member 10 that spans almost the entire length of the developer transport chamber, and this opening/closing member 10 rotates around a shaft 10a to open the bottom, distributing the developer evenly. This constitutes an even supply mechanism that supplies the developer to the stirring chamber 5 at the same time.

In such a one-component developing device, when the supply valve 9b of the developer supply section 9 is opened based on a signal from the toner sensor 12 and developer is supplied to the developer transport chamber 7, the developer transport starts. The member 8 operates to transport the developer within the developer transport chamber 7 so that it is evenly distributed in the image width direction (the axial direction of the developer carrier). After the developer is evenly distributed in the image width direction, the opening/closing member 10 at the bottom of the developer transport chamber is opened, and the developer in the developer transport chamber 7 falls into the developer stirring chamber 5. 5, the developer is evenly supplied. The developer supplied into the developer stirring chamber 5 is supplied to the developer carrier 3, and is consumed by development in a development area where the developer carrier 3 and the electrostatic latent image holder 2 closely face each other. Ru. As a result, when the amount of developer stored in the developer stirring chamber 5 decreases, the toner sensor 12 detects this, and the above-described process of supplying the developer to the developer stirring chamber is repeated.

Next, a method of controlling the supply valve 9b of the developer supply section 9 and the opening/closing member 10 of the developer transport chamber 7 in the one-component developing device will be explained. FIG. 4 is a schematic diagram sequentially showing an example of a method for supplying developer by controlling the supply valve 9b and the opening/closing member 10. When sufficient developer is contained in the developer stirring chamber 5 (hereinafter referred to as the stirring chamber), the supply valve 9b is closed and the developer transport chamber 7 (hereinafter referred to as the transport chamber) is completely free of developer. do not have. However, the auger 8 in the transport chamber 7 always rotates while the developing device is in operation. [Figure (a)]

When development is repeated and the developer in the stirring chamber 5 is consumed and becomes below a preset level, a signal from a toner sensor provided in the stirring chamber 5 causes the supply valve 9b to close. The developer in the opened hopper 9a is guided into the action range of the auger 8 and transported to the transport chamber 7. [(
b) Figure]

When a preset amount of developer is introduced into the transport chamber 7, the supply valve 9b closes and the supply of toner into the transport chamber 7 is stopped, and the auger 8 removes the image in the transport chamber 7. The developer is conveyed so as to be uniformly distributed in the width direction. [Figure (c)] When the time necessary for the amount of developer in the transfer chamber 7 to become uniform has elapsed, the opening/closing member 10 of the transfer chamber 7 opens and the entire amount of developer in the transfer chamber 7 is transferred to the stirring chamber 5. fall into. [Figure (d)]

When the time required for the developer in the transport chamber 7 to move into the stirring chamber 5 has elapsed, the opening/closing member 10 of the transport chamber 7 is closed, resulting in the state shown in FIG. Further, when the development is repeated, the amount of developer in the stirring chamber 5 decreases, and when this is detected by the toner sensor, the above operation is repeated.

The method for supplying the developer by controlling the supply valve 9b and the opening/closing member 10 as described above can also be carried out in the order shown in FIG. In this method, when the entire amount of the developer in the transport chamber 7 is put into the stirring chamber 5 and a sufficient amount of developer is in the stirring chamber 5, the opening/closing member 10 is closed;
The supply valve 9b is opened and the developer is introduced into the transport chamber 7. In the transport chamber 7, the developer is transported by an auger 8 so as to be uniformly distributed in the image width direction. [Figure (a)]

When the developer is uniformly distributed, the rotation of the auger 8 is stopped. [Figure (b)] On the other hand, when development is repeatedly performed, the developer in the stirring chamber 5 is supplied to the developer carrier and is consumed and reduced. [Figure (c)] When the amount of developer in the stirring chamber 5 falls below a preset level, the toner sensor detects this, and the opening/closing member 10 is released based on the signal generated by the toner sensor. [Figure (d)] As a result, the entire amount of the developer in the transport chamber 7 is thrown into the stirring chamber 5, and when the charging is finished, the opening/closing member 10 is closed and the state shown in figure (a) is obtained, and the above operation is repeated.

Next, another embodiment of the present invention will be described. FIG. 6 is a schematic cross-sectional view showing the structure of a one-component developing device according to a second embodiment of the present invention, and is a cross-sectional view perpendicular to the axial direction of the developer carrier. In this one-component developing device, a developer transport chamber 17 provided at the upper part of the developer stirring chamber 5 has an arcuate cross section that is open at the upper part and convex downward, and extends approximately in the axial direction of the developer carrier. It is composed of arc cross-sectional members 20 having equal cross sections, and the opening at the top is approximately 120° or less at the central angle of the arc. The developer transport chamber 17 is provided in a range of approximately the same length in parallel with the axial direction of the developer carrier 3, and is supported so that the arcuate cross-section member 20 can rotate around its axis. This constitutes an even supply mechanism. An auger 8 that rotates independently of the arc cross-section member 20 is provided in the developer transport chamber 17, and as it rotates, the developer in the developer transport chamber 17 is evenly distributed in the axial direction. Transport as required. The developer supply section 9 that supplies developer into the developer transport chamber 17 is the same as that in the first embodiment. Further, the developer carrier 3, the developer stirring chamber 5, the developer stirring and supplying member 6, and the toner sensor 12 are also the same as those in the first embodiment.

In such a developing device, the developer supply section 9
The developer is supplied into the developer transport chamber 17 from the developer transport chamber 17, and the developer is transported within the developer transport chamber 17 so as to be evenly distributed in the image width direction by the rotation of the auger 8. When the developer is introduced into the developer stirring chamber 5 after the developer is distributed evenly, the circular arc cross-section member 20 forming the developer transport chamber 17 is used.
The member is rotated so that the opening that was at the top is now located at the bottom, and the developer stored in the member is dropped into the developer stirring chamber 5.

The control of dropping the developer, introducing the developer from the hopper 9a into the developer transport chamber 17, and charging the developer into the developer stirring chamber 5 is as shown in FIG. 4 or 5 in the same manner as in the first embodiment. This can be done in the order shown below.

[0026]

As explained above, in the one-component developing device of the present invention, the developer is once introduced into the developer transport chamber provided along the axial direction of the developer carrier. After being conveyed so as to be evenly distributed in the axial direction, the developer is supplied to the developer stirring chamber, and within the developer stirring chamber, the developer is hardly conveyed in the axial direction of the developer carrier. Therefore, the developer that adheres to the surface of the developer carrier and receives a load, resulting in a decrease in the amount of charge, does not accumulate in large amounts at one end in the image width direction, and the developer that receives the load is distributed evenly. The distribution will be as follows. Therefore, even if development is repeated many times, there is little decrease in image density.
To obtain a one-component developing device capable of performing good development without causing unevenness in image density between one end and the other end in the image width direction.

[Brief explanation of drawings]

FIG. 1 is a partially transparent schematic perspective view showing a one-component developing device according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view taken along the line II shown in FIG. 1;

3 is a schematic cross-sectional view taken along the line II-II shown in FIG. 2. FIG.

FIG. 4 is a schematic diagram showing an example of a method of supplying developer to the one-component developing device of the above embodiment.

FIG. 5 is a schematic diagram showing another example of a method of supplying developer to the one-component developing device of the above embodiment.

FIG. 6 is a schematic cross-sectional view showing the configuration of a one-component developing device according to a second embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view showing the configuration of a conventional one-component developing device.

8 is an explanatory diagram showing the structure of the conventional one-component developing device shown in FIG. 7 in the axial direction of the developer carrier.

FIG. 9 is a schematic cross-sectional view showing a conventional one-component developing device having a trimming member as a developer regulating member.

[Explanation of symbols]

1 Housing 2 Electrostatic latent image holder 3 Developer carrier 4 Developer regulating member 5 Developer stirring chamber 6 Developer stirring and supplying member 7 Developer transporting chamber 8 Developer transporting member (auger) 9 Developer supplying section 10 Opening/closing Member 12 Toner sensor 13 Magnet roll 17 Developer transport chamber

Claims (1)

[Claims] 1. A developer carrier disposed opposite to the electrostatic latent image carrier and transporting a one-component developer while adhering to its surface;
a developer regulating member that regulates the amount of developer attached to the developer carrier; and a developer regulating member that is provided along the axial direction of the developer carrier and stirs the developer and substantially the entire length of the developer carrier in the axial direction. In a one-component developing device having a developer stirring chamber capable of supplying developer to the developer stirring chamber, the developer carrying member is provided substantially parallel to the axial direction of the developer carrier over almost its entire length, and the developer is supplied to the developer stirring chamber. a developer transport chamber that can temporarily store the developer separated from the developer stored in the developer transport chamber; a developer supply section that supplies the developer to the developer transport chamber; and a developer supply section that supplies the developer to the developer transport chamber and temporarily stores the developer. A developer transport device transports the developer so as to be evenly distributed in the axial direction of the developer carrier; 1. A one-component developing device comprising: an even supply mechanism that supplies agent substantially evenly in an axial direction of a carrier.