JPH08248772A - Developing device - Google Patents

Abstract

PURPOSE: To provide a developing device having degree of freedom of a layout for miniaturizing, higher than that of a conventional device. CONSTITUTION: A developing roller 2 incorporating a magnet is disposed to expose a part thereof from an opening part faced to a photoreceptor drum, a lower carrying roller 5 is disposed proximately to the developing roller 2 to be faced thereto and in proximity to an upper carrying roller 4 located in the upper part of the roller 2 and a toner supplying roller 3 is disposed in proximity to or in contact with the upper carrying roller 4 on the right of it, as well. At this time, both shafts of the lower carrying roller 5 are in an electrical floating state by an insulating member, etc. Then, stirring screws 6 and 7 are vertically arranged on the left of the upper carrying roller 4 and a developing doctor 8 regulating the developer on the developing roller 2 is arranged on the lower side of the screws 6 and 7. On the other hand, a supplying roller 9 and a layer thinning blade 10 are arranged to abut on the surface of the supplying roller 3 and an agitator 11 and a toner carrying screw 12 are arranged in the upper part of the supplying roller 9 as well.

Description

Detailed Description of the Invention

[0000]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device applied to an image forming apparatus such as a copying machine, a facsimile or a printer, and more specifically, a two-component developing device having a magnet inside and a toner and a carrier. A developer carrying member carrying an agent,
A stirring member for stirring and mixing the two-component developer, a conveying member having a magnet inside, for conveying the developer on the developer carrying member to the stirring member side, and the conveying member for conveying the toner. The present invention relates to a developing device having a replenishing member that replenishes a member, and a driving unit that drives the developer carrying member and each member.

[0001]

2. Description of the Related Art Conventionally, as a developing device of this type, a thin toner layer is formed on a replenishing roller, and the replenishing roller is brought into proximity with or in contact with a developer on a developing roller having a magnet therein for development. It is known to supply toner to the agent.

[0002]

FIG. 7 shows an example thereof. In this developing device, a developing roller 2 with a built-in magnet is arranged so that a part of the developing roller 2 is exposed from an opening facing the photosensitive drum. Further, in the unit 1, a toner replenishing roller 3, upper and lower conveying rollers 4, 5, upper and lower conveying screws 6, 7 and a developing doctor 8 also serving as a left side wall of the unit 1 are arranged so as to face the developing roller 2. It is arranged. Further, a supply sponge roller 9 and a thinning blade 10 are arranged so as to come into contact with the surface of the toner supply roller 3, and an agitator 11 and a toner conveying screw 12 are arranged above the supply sponge roller 9. .

Here, in the developing unit 1, a lower end is attached to a peripheral wall of the unit and an upper end is in contact with the toner replenishing roller 3 at a predetermined pressure, a replenishing roller seal 13, the toner replenishing roller 3, and the thinning blade 10. And a blade holder 1 in which the upper part of the thinning blade 10 is attached to the lower end and the upper end is attached to the peripheral wall of the unit.
The developing roller 2 is formed by a partition wall 4
And the like, and is divided into a developing agitating chamber in which the agitator 11 and the like are disposed. Then, in the toner storage chamber, the upper toner transport screw 12
The toner sent from a toner tank (not shown) via the toner storage chamber is stored in the developing agitation chamber. The developer and the toner are replenished from the toner storage chamber via the toner replenishing roller 3. Is housed. In the figure, reference numeral 16 is a right casing forming the right side surface of the toner storage chamber, reference numeral 17 is an upper cover forming the upper surface of the storage chamber, and reference numeral 18 is developer replenishment forming the upper surface of the developing stirring chamber. The port cover, reference numeral 19 denotes a developing casing that constitutes the lower surface of the developing stirring chamber.

By the way, conventionally, it has been desired to downsize such a developing device because of the necessity of downsizing the entire device to which the developing device is applied. In order to reduce the size of the developing device, first, it is conceivable to reduce the diameter of the developing roller 2. However, in the conventional layout, the developing roller 2 and the replenishing roller 3 are disposed so as to face each other, and the developer in the developing stirring chamber is arranged. In addition, the method of replenishing the toner from the toner storage chamber is adopted, and there is a restriction that the replenishing roller 3 must be arranged around the developing roller 2. Therefore, it is possible to reduce the diameter of the supply roller 3 as well.
The toner adhesion amount on the replenishment roller 3 is determined by the range of the optimum toner charge amount for achieving both prevention of deterioration of a developed image due to insufficient charge of the developer and maintenance of toner replenishment property, and the toner charge amount is almost the same. The amount and the toner adhesion amount are determined with a specific relationship. Therefore, in order to sufficiently charge the toner, it is necessary to speed up the rotation of the supply roller 3. However, when the replenishment roller 3 is rotated at a high speed, toner adheres to the blade contacting the replenishment roller 3, a thin layer defect due to toner filming on the replenishment roller 3, and toner leakage from the seal portion of the replenishment roller 3. Since it causes a problem that it is easy to induce,
There is a limit to reducing the diameter of the supply roller 3. Therefore, under the constraint that the developing roller 2 and the replenishing roller 3 are arranged to face each other to replenish the toner, the degree of freedom in the layout configuration is small and it is difficult to downsize the developing device.

In general, the magnetic pole of the developing roller 2 is a main pole for developing the latent image on the photosensitive drum in the image forming apparatus in the developing area, and the toner on the replenishing roller 3 is the developing roller. In the replenishment area for replenishing the carrier on the second carrier, a replenishment pole for raising the carrier and a carrier magnetic pole for carrying the carrier are required. For this reason, design to ensure a sufficient surface magnetic force, and
Mass production of a stable developing roller with less variation in surface magnetic force is difficult.

In recent years, as a means for improving the image quality, the adoption of a developing system in which an AC developing bias is applied to the developing roller 2 is increasing. With this development method,
The amount of the developer on the developing roller 2 is set to be smaller than that of the conventional developing method in which a DC bias is applied in order to improve the developing agent blush on the image and the solid uniformity. The decrease in the developing ability by this amount is compensated by applying an AC bias to activate the toner and promote the movement of the toner from the developing roller 2 to the photosensitive drum side. As a result, the developing roller 2 for the photosensitive drum
The surface linear velocity ratio can be reduced to reduce the load on the drive system. However, regarding the surface of toner replenishment, if the amount of developer on the developing roller 2 is set to a small amount, the amount of contact between the toner and the developer is reduced in the nip portion between the developing roller 2 and the replenishing roller 3, so that toner replenishment is performed. It leads to deterioration of sex. Therefore, it is conceivable to reduce the replenishing roller gap in order to increase the contact between the toner and the developer, but when the replenishing roller gap is reduced, there is a problem that the control of the gap accuracy becomes strict. Further, since the gap management is strict, for example, like the developing device proposed in Japanese Patent Application No. 4-298114 shown in FIG. 8, the developing device of FIG. 7 is divided to replace and clean the inside of the developing device. In the case of the developing device that is made possible, the structure of the joint tends to be complicated in order to obtain the gap accuracy, and there is also a problem that the workability at the time of disassembly or assembly is impaired.

Further, in the thin layer replenishment system in which the thin toner layer formed on the replenishing roller 3 is replenished to the developer, the following is related to the bias applied to the replenishing roller 3 in order to stabilize the toner replenishing amount. There was a problem. For example, in the case of the reversal development method in which the toner in the developer on the developing roller 2 is adhered to the exposed portion on the photosensitive drum to visualize the toner, the replenishing bias applied to the replenishing roller 3 during toner replenishment is A bias larger than the bias is required. Therefore, there are problems such as an increase in the size of the power supply device, restrictions on the device layout from the viewpoint of safety measures against bias voltage leakage, and an increase in cost. Further, in the case of an image forming apparatus aiming at high image quality and image stabilization, there is one that variably controls the developing bias by process control. In this case, the high-voltage replenishment bias as described above is required, and in addition, the replenishment bias is variably controlled so that a predetermined potential difference is obtained according to the change in the development bias. There was a problem that was raised. In particular, in the developing device that activates the toner by applying an AC bias to the developing roller 2 and moves the toner to the photosensitive drum side due to the demand for the image quality, the moment between the developing roller 2 and the replenishing roller 3 is increased. Large potential difference is applied. Further, the material of the replenishing roller 3 is restricted in order to favorably charge the toner when forming a thin layer of the toner. There was a case where a certain material had to be adopted. Therefore, the developing roller 2
When a large potential difference is instantaneously applied between the replenishment roller 3 and the supply roller 3, there is a problem that a bias leak occurs.

The present invention has been made in view of the above problems. A first object of the present invention is to increase the degree of freedom of layout in comparison with a conventional apparatus in order to downsize the developing apparatus. To provide a developing device. A second object of the invention is to provide a developing device capable of maintaining the gap accuracy between the members that bring the toner and the developer into contact with each other and enabling replacement and cleaning inside the developing device. A third object of the invention is to provide a developing device that can stably supply toner to the developer. A fourth object is to provide a developing device capable of simplifying bias control and reducing costs. A fifth object of the invention is to provide a developing device capable of preventing bias leak.

[0009]

In order to achieve the first object, the developing device according to claim 1 has a magnet inside.
A developer carrying member for carrying a two-component developer consisting of toner and carrier, a stirring member for stirring and mixing the two-component developer, and a magnet inside, a developer on the developer carrying member. A developing member having a feeding member for feeding the toner to the stirring member side, a replenishing member for replenishing the toner, the developer carrying member, the stirring member, the feeding member, and a driving unit for driving the replenishing member. In the apparatus, the replenishment member is arranged in proximity to or in contact with the conveying member so as to face it.

In order to achieve the above second object,
The developing device according to claim 2 is the developing device according to claim 1,
The side plate pair of the developing device is configured by a first side plate pair that supports at least the developer carrying member, and a second side plate pair that positions and supports at least the transport member and the replenishment member. To do.

In order to achieve the above third object,
The developing device according to claim 3 is the developing device according to claim 1,
The driving means can be driven so that the surface linear velocity of the conveying member facing the replenishing member satisfies a predetermined toner replenishing efficiency in accordance with the amount of the developer carried on the developer carrying member. It is characterized by being configured.

In particular, the developing device according to claim 4 is the developing device according to claim 1, wherein in order to accelerate the toner supply from the replenishing member to the conveying member facing the replenishing member, the replenishing member and the conveying member. And a bias applying means for applying a bias to at least one of the above.

In order to achieve the above-mentioned fourth object,
The developing device according to claim 5 is the developing device according to claim 4,
The bias applying means sets at least one of the bias applied to the conveying member and the bias applied to the replenishing member to a fixed bias, and the bias applied by the applying means is applied to the developer carrying body by another system. It is characterized in that the bias is applied so that the bias can be variably controlled.

In particular, the developing device of claim 6 is characterized in that, in the developing device of claim 4, the absolute value of the bias voltage is set smaller than the absolute value of the average voltage applied to the developer carrying member. It is what

In particular, the developing device of claim 7 is characterized in that, in the developing device of claim 5, either one of the conveying member and the replenishing member is grounded.

Further, in order to achieve the fifth object,
A developing device according to claim 8 is the developing device according to any one of claims 1 to 7, wherein the carrying member is a first carrying roller for carrying the developer and a second carrying roller for carrying the developer to the stirring means. And the first conveying roller is arranged close to and facing the developer carrying member, and the second conveying roller is arranged close to and facing the first conveying roller, and also with respect to the replenishing roller. It is arranged so as to be close to or in contact with each other, and promotes toner supply from the replenishment member side to the second conveyance roller side between the replenishment member and the second conveyance roller facing the replenishment member. It is characterized in that a bias having a potential difference is applied to at least one side so that the first transport roller is electrically floated.

According to a ninth aspect of the present invention, there is provided a developing device having a magnet therein and carrying a two-component developer comprising a toner and a carrier, and agitating and mixing the two-component developer. A stirring member, a conveying member that has a magnet inside and that conveys the developer on the developer carrying member to the stirring member side, a replenishing member that replenishes the toner, and the developer carrying member,
In a developing device having the agitating member, the conveying member, and a driving unit that drives the replenishing member, the replenishing member is opposed to the developer on the developer carrier so as to be close to or in contact with the developer. It is arranged so as to have one replenishment region and a second replenishment region facing so as to be close to or in contact with the developer on the transport member, and between the replenishment member and the developer carrier, and A replenishing bias for applying a replenishing bias having a potential difference between the replenishing member and the conveying member to promote toner supply from the replenishing member to the developer on the developer carrying member or on the conveying member. It is characterized in that an applying means is provided.

Particularly, the developing device of claim 10 is the same as that of claim 8.
Alternatively, in the developing device of No. 9, the driving means is driven so that the surface of the replenishing member and the surface of the developer carrying member or the conveying member arranged to face the replenishing member move in mutually opposite directions. It is characterized by being configured in.

Particularly, the developing device of claim 11 is the same as that of claim 8.
Or the linear velocity ratio between the replenishment member and the developer in the first replenishment area, and the line between the replenishment member and the developer in the second replenishment area. It is characterized in that the driving is performed so that the speed ratio is different from each other.

Particularly, the developing device of claim 12 is the same as that of claim 8.
Alternatively, in the developing device of Item 9, the replenishment member and a plurality of members facing the replenishment member have different gaps.

Particularly, the developing device of claim 13 is the same as that of claim 9.
In the developing device, the bias applying means is configured such that the bias applied to the developer carrying member and the bias applied to the conveying member are different from each other.

[0022]

In the developing apparatus of the first aspect, the carrier component on the developer carrying member is carried to the stirring member side while being carried on the carrying member by the magnetic force of the carrying member. During the course of this developer transportation, the toner is replenished to the carrier on the transportation member by the replenishment member arranged so as to be close to or in contact with the carrier transported on the transportation member. Then, the two-component developer is conveyed to the stirring member side by the conveying member, and the developer stirred by the stirring member is carried on the developer carrier. As described above, the toner is replenished to the developer between the members by making the replenishing member face the conveying member. Therefore, as in the conventional device, the toner is replenished near the developer carrying member. Since it is not necessary to dispose members facing each other, the degree of freedom in the layout configuration of the developing device is increased.

In the developing device of the second aspect, the replenishing member and the conveying member are supported by the integral side plate, so that the gap between the two members can be maintained with a certain accuracy. This reduces variations in the contact state between the toner on the replenishing member and the carrier on the conveying member. Further, the carrier is forcedly carried from the developer carrying member by the carrying member by the magnetic force of the carrying member, and
Since toner is not replenished between the developer carrying member and the carrying member, the gap between the developer carrying member and the carrying member does not require strict gap accuracy as in the conventional device.

In the developing device of claim 3, the driving means causes the surface linear velocity of the conveying member to replenish the toner from the replenishing member to the conveying member according to the amount of the developer on the developer carrier. Drive the transport member to optimize efficiency. For example, in a developing device having a small amount of developer carried on the developer carrying member, such as a developing device adopting a method of applying an AC developing bias to the developer carrying member, the surface line of the carrying member is By increasing the speed to increase the amount of the developer on the conveying member and facing the replenishing member, the contact between the developer on the conveying member and the toner on the replenishing member in the nip is increased to replenish the toner. Improve efficiency. Conversely, for example, in a developing device having a large amount of developer on the developer carrying member, such as a developing device adopting a system of applying a DC developing bias to the developer carrying member,
The linear velocity of the surface of the carrying member is reduced to reduce the amount of the developer carried by the carrying member, and the toner is prevented from being supplied only to the surface of the developer on the carrying member at the nip with the replenishing member. To do.

In the developing device of claim 4, an electric field is formed so as to move the toner from the replenishing member to the conveying member by the bias applied between the replenishing member and the conveying member facing the replenishing member. To be done. By this electric field,
Toner replenishment from the replenishment member to the transport member is promoted.

In the developing device of the fifth aspect, since the member facing the replenishing member is not the developer carrying member but the conveying member, the bias applied to the replenishing member for moving the toner is the developing bias. It is not necessary to change it by following the change of. Therefore, an electric field is formed so as to move the toner from the replenishing member to the conveying member by the fixed bias applied to at least one of the replenishing member and the conveying member. This electric field promotes toner replenishment from the replenishment member to the transport member.

In the developing device of the sixth aspect, by applying a voltage having an absolute value smaller than the developing bias to the replenishing member or the conveying member, the burden on the power source is reduced and the bias voltage leakage countermeasure is simplified. Turn into. Since the member facing the replenishing member is not the developer carrying member but the carrying member, it is not necessary to change the bias applied to the carrying member in accordance with the developing bias.

In the developing device of claim 7, either one of the carrying member and the replenishing member, for example, a part of a ground wire of a toner concentration sensor or a toner end sensor provided in the developing device is connected. By commonly grounding or grounding a reference pin of the developing device fitted to the side plate of the image forming apparatus, the toner is moved from the replenishing member to the conveying member between both members. Because of the relative potential gradient, toner replenishment from the replenishment member to the transport member is promoted without using a complicated bias control mechanism.

In the developing device of the eighth aspect, since the first carrying roller adjacent to the developer carrying body is electrically floated, for example, between the developer carrying body and the second carrying roller. When biases having different potentials are applied to the developer, a bias leak does not occur between the developing bias and the carrying bias even if the developer used has a relatively low resistance value. (Hereinafter, margin)

In the developing device of claim 9, for the two-component developer, there are two locations on the replenishment member, namely, a first replenishment area and a second replenishment area, that is, between the developer carrier and the replenishment member. Alternatively, since the toner is delivered by the magnetic force between the replenishing member and the conveying member, the toner can be efficiently replenished to the developer without driving the replenishing member at a high rotation speed. Also, when delivering this toner,
The toner taken in near the surface layer of the developer is dispersed in the developer as the toner is peeled off from the replenishment member. The unevenness of the toner concentration in the developer near the inner surface layer is alleviated, and the toner replenishing efficiency in the second replenishing area is further enhanced.

In the developing device according to the tenth aspect of the present invention, in the driving means, the surface of the replenishing member and the surface of the developer carrying member or the conveying member arranged to face the replenishing member move in mutually opposite directions. Thus, the thin toner layer formed on the replenishment member reaches the first replenishment region after passing through the second replenishment region on the downstream side in the developer transport direction. Then, the toner on the replenishment member in the first replenishment area becomes the replenishment residual toner after the second replenishment area. The toner concentration of the developer in the first developing area is lowered after passing through the developing area, and the toner easily moves into the developer even when the amount of toner adhered on the replenishment member is small due to the replenishment residue. .

In general, the surface linear velocity of the developer bearing member is correlated with the linear velocity ratio of the surface linear velocity of the image bearing member of the image forming apparatus in the developing area to the image quality, and the required developing ability. Will be prioritized. On the other hand, the adhesion amount of the thin toner layer formed on the replenishment member is limited to some extent by the predetermined charge amount range that satisfies the quality of the developed image and the toner replenishment property. Therefore, setting the toner replenishment ability so as to follow the specified developed image density naturally determines the linear velocity required for the replenishment member. Therefore, it cannot be said that the linear velocity ratio between the developer carrying member and the replenishing member is such that the developing ability and the toner replenishing ability are optimized.

On the other hand, in the developing device of claim 11,
Even if the toner concentration in the developer and the toner concentration on the replenishment member in the first replenishment region and the second replenishment region are different, at least one or more locations of the replenishment member are developed in the second replenishment region. Since it opposes the conveying member other than the developer carrying member, the linear velocity ratio of the developer carrying member is such that the maximum toner replenishing efficiency to the developer on the developer carrying member can be obtained. Even if the linear velocity ratio is different, the linear velocity ratio can be optimized.

Here, the magnets facing the replenishment member may differ in the outer diameter and the surface shape of the developer carrying member such as the groove shape. Further, the conditions of the surface magnetic force of the first replenishment region and the second replenishment region are different from each other, and the developer holding ability due to the magnetic force of the magnet is also different due to the difference in developer toner concentration due to the toner replenishment order. There is a difference in developer holding ability between the replenishment area and the second replenishment area. When the linear velocity of the developer carrying member or the conveying member facing the replenishment member in the first replenishment region and the second replenishment region is different from that of the replenishment member, the layer thickness of the developer on the replenishment member Is also different. Furthermore, when a carrier of developer is attracted to the replenishment member side due to a difference in toner adhesion amount on the replenishment member due to the order of toner replenishment, for example, when the developer carrier is attracted to the replenishment member side, There is a possibility that a so-called carrier rising phenomenon may occur which enters the housing portion.

In this respect, in the developing device according to the twelfth aspect, there is a difference in developer transporting ability and a developer layer in a gap between the replenishing member and the developer carrying member or the replenishing member which is arranged to face the replenishing member. The optimum gaps are set according to the difference in the thickness of the toner. Therefore, as in the case where the gap is set constant without considering these differences, the retention of the developer and the toner storage unit There is no chance that the carrier will go up.

The developing bias applied to the developer carrying member is generally determined by giving importance to the developed image in the developing area. Since the replenishment bias for replenishing the thin layer toner on the replenishment member to the developer on the developer carrier must have a predetermined potential with reference to the development bias, the replenishment bias is the development The pressure is higher than the bias. Further, since it is necessary to consider the bias voltage leakage prevention and the safety at the time of leakage, there may be some restrictions.

On the other hand, in the developing device of claim 13,
In addition to the developer carrier, in order to contribute to toner replenishment,
There is a transport member that transports the developer facing the replenishment member, and a bias that is different from the development bias and that is optimized in consideration of toner replenishment efficiency is applied to the transport member. As a result, the toner replenishment efficiency can be improved.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a developing unit of an electrophotographic copying machine (hereinafter referred to as copying machine) which is an image forming apparatus will be described below. First, an outline of the developing device of this embodiment will be described. FIG. 1 is a schematic configuration diagram of the developing device of this embodiment. The built-in member of the developing unit 1 of the present embodiment is provided with a developing roller 2 with a built-in magnet so that a part thereof is exposed from an opening facing the photoconductor drum of the copying machine, and is close to the developing roller 2. A lower conveying roller 5 is arranged so as to face the upper conveying roller 4 located above the upper conveying roller 4, and a toner replenishing roller 3 is arranged close to or in contact with the right side of the upper conveying roller 4 in the figure. Has been done. Here, the lower conveyance roller 5 is electrically floated by supporting both shafts with an insulating member or the like.
The upper and lower stirring screws 6 and 7 are arranged on the left side of the upper conveying roller 4, and a developing doctor 8 for regulating the developer on the developing roller 2 is arranged below the upper and lower stirring screws 6 and 7. Further, a supply roller 9 and a thinning blade 10 are arranged so as to come into contact with the surface of the supply roller 3, and an agitator 11 and a toner conveying screw 12 are arranged above the supply roller 9. Further, in the developing unit 1, the replenishing roller seal 13, the replenishing roller 3, and the thinning blade 1 are provided.
0 and a partition formed by the blade holder 14 divides the development stirring chamber and the toner storage chamber,
The toner is stored in the toner storage chamber, and the two-component developer (hereinafter, referred to as
A developer is stored).

Here, as the material of the replenishing roller 3, a rubber material such as NBR (nitrile rubber) or silicon rubber, or a resin material such as fluororesin is used, and this rubber material or resin material is not used for the entire roller. It may be provided only on the roller surface layer. Further, as the material of the supply roller 3, a roller made of metal such as aluminum or stainless steel can be used. As the material of the thinning blade 10, a thin metal such as carbon steel, a rubber material such as silicon rubber, a resin material such as fluororesin, and the like having appropriate elasticity are preferable. The supply roller 9 may be formed by winding a metal cored bar on which foamed polyurethane is dispersed with carbon and subjected to a conductive treatment. When selecting the materials for the supply roller 3, the supply roller 9, and the thinning blade 10,
It is determined in consideration of the charge polarity of the toner, the required charge amount, and the like.

The upper and lower conveying rollers 4 and 5 have block magnets of N and S2 poles (not shown) incorporated therein, and rotate counterclockwise so that the developer from the developing roller 2 is drawn up and conveyed. Has become. Above stirring screw 6
Rotates counterclockwise in the gutter-shaped screw casing 6a, drops the developer from the peripheral surface of the upper conveying roller, and conveys the developer received by the screw casing 6a to the inner side of the developing device. . This screw casing 6a
A developer dropping opening (not shown) is formed in the lower portion on the back side, and an overflow opening (not shown) extending in the width direction is formed in the side wall opposite to the vertical conveying rollers 4, 5. The lower stirring screw 7 rotates counterclockwise in the developer reservoir above the developing roller 2 and conveys the developer from the back side of the developing device to the front side.

The operation of this developing device will be described.
The developing roller 2 rotates counterclockwise and develops the electrostatic latent image on the photosensitive drum into a visible image by a bias voltage applied from a developing bias source. The replenishing roller 3 arranged close to the developing roller 2 rotates counterclockwise when a toner replenishing clutch (not shown) is turned on. The supply roller 9, the thinning blade 10, and the supply roller seal 13 are pressed against the peripheral surface of the supply roller 3 in the axial direction, and the toner in the toner storage chamber is supplied by the supply roller 9 rotating at the same time as the supply roller 3. It is rubbed on the roller 3, conveyed along with the rotation of the replenishment roller 3, and continuously thinned on the replenishment roller 3 by the thinning blade 10. The toner thinned on the replenishing roller 3 is charged by a series of frictional actions, and is taken into contact with the developer magnetized and conveyed on the upper conveying roller 4 by a contact and electric action, and as a result, Increase the toner concentration in the carrier.

The carrier passing between the developing roller 2 and the replenishing roller 3 is pumped up to the lower conveying roller 5 by the magnetic force of the lower conveying roller 5 at a position facing the lower conveying roller 5. The carrier drawn up by the lower carrying roller 5 is further drawn up by the upper carrying roller 4 to take in the developer magnetized and carried on the upper carrying roller 4 by contact and electric action, and then the upper carrying roller 4 When it reaches the point where it is not influenced by the magnetic force on the side of the screw casing 6a beyond the top of the, it falls by its own weight over the entire width like a waterfall and is received by the screw casing 6a. Then, it is conveyed to the rear side of the developing device by the lower conveying screw in the screw casing 7a and falls from a developer dropping opening (not shown) formed in the lower portion on the rear side of the screw casing 7a. Further, part of the developer received by the screw casings 6a and 7a also drops from the overflow opening. Then, the developer dropped from the developer dropping opening or the overflow opening forms a developer pool above the developing roller 2 and is conveyed to the inner side of the developing device by the lower stirring screw 7 in the developer pool. To be done. The developer which is sufficiently cross-mixed by the vertical stirring screws 6 and 7 is carried on the developing roller 2 by the magnetic force of the developing roller 2 and conveyed, and is regulated to a predetermined thickness by the developing doctor 8 on the way. After that, it is conveyed to a portion facing the photosensitive drum.

According to the above construction, it is not necessary to dispose the replenishing roller 3 for replenishing the toner on the carrier on the developing roller 2 in the vicinity of the developing roller 2 unlike the conventional apparatus, so that the developing unit 1 Greater flexibility in layout. This has the following advantages. For example, even if the diameter of the replenishing roller 3 cannot be reduced due to the problem that high-speed rotation causes a problem, the developing unit 1 can be configured by reducing the diameter of only the developing roller 2. Therefore, the driving torque of the developing roller 2 and the power consumption can be reduced, so that the driving device and the power supply device can be downsized, and the developing unit 1 can be reduced.
The overall size can be reduced. Further, for example, even when the polar angle of the magnet built in the developing roller 2 is displaced or the surface magnetic force is varied, the replenishing roller 3
Since less carrier adheres to the toner, it is possible to reduce the risk of carrier being mixed into the toner storage chamber. Further, in setting the magnetic force distribution of the developing roller 2, the surface magnetic force of the magnetic pole, which is arranged at a position facing the replenishing roller in the conventional apparatus, is stronger than that in the conventional apparatus because it only needs to contribute to the conveyance of the developer. Does not require magnetic force. For this reason,
The number of parameters to be considered when setting the magnetic force distribution is reduced, and the setting can be facilitated. Therefore, the mass production of the developing roller 2 is facilitated as compared with the related art.

Next, the bias applied to accelerate the movement of the toner in the developing unit 1 will be described. As shown in FIG. 1 described above, a developing bias in which a high-voltage negative DC component is superimposed on an AC component is applied to the developing roller 2 in order to visualize the latent image on the photosensitive drum. Note that this DC component can be changed by process control. Furthermore,
The replenishing roller 3 and the upper conveying roller 4 facing the replenishing roller 3 are provided with a potential difference such that the negatively charged toner formed in a thin layer on the replenishing roller 3 moves to the developer on the upper conveying roller 4. The owning DC bias is applied. Here, since the thin toner layer on the replenishing roller 3 is replenished to the upper conveying roller 4 instead of the developing roller 2, the replenishing roller 3
The bias applied to and need not be higher than the developing bias as in the conventional apparatus. For this reason, since it suffices that the potential gradient is such that toner can be simply moved, the bias applied to the upper conveyance roller 4 is low. Therefore, the bias of the replenishment roller having a predetermined negative replenishment potential with respect to the potential of the upper transport roller 4 is low, and the bias is fixed.

According to this structure, it is not necessary to apply a voltage higher than the developing bias between the replenishing roller 3 and the upper conveying roller 4, unlike the conventional apparatus, so that the load on the power source can be reduced and the bias voltage can be reduced. It also makes it easier to prevent leaks. Although biases having different potentials are applied to the developing roller 2 and the upper conveying roller 4, the lower conveying roller 5 located close to the developing roller 2 and the upper conveying roller 4 is electrically floated. Since it is in the state of
For example, even if the developer used has a relatively low resistance value, the high-potential developing bias does not leak to the low-potential carrying bias. Therefore, abnormalities such as image loss and toner supply failure due to bias leak do not occur, and a developed image of stable quality can be obtained.

As described above, a relative potential gradient for moving the toner from the replenishing roller 3 to the upper conveying roller 4 may be provided between the upper conveying roller 4 and the replenishing roller 3. Therefore, either one of the upper conveying roller 4 and the replenishing roller 3 may be grounded by sharing a part of the signal line of the toner concentration sensor or the toner end sensor provided in the developing unit 1, By grounding a reference pin or the like of the developing unit 1 fitted to the side plate of the main body of the image forming apparatus, a relative potential gradient for moving the toner from the replenishing roller 3 to the upper conveying roller 4 is provided between both rollers. You may have it. For example, in the case of a device in which the upper conveyance roller 4 is grounded as shown in FIG.
Since one bias is unnecessary, the load on the power source is reduced, and the power source device can be downsized. In addition, in terms of safety such as measures against leakage of bias voltage on the grounded side, in the conventional device, it is necessary to take a large space distance to prevent application due to leakage and to add a flame-retardant member. However, since such a measure is not necessary, there is an advantage that the device can be simplified and the degree of freedom of layout is increased. Further, in FIG. 3, when the replenishing roller 3 is grounded, the same effect can be obtained by applying a positive bias to the upper conveying roller 4 side.

As shown in FIGS. 1 and 3, the upper conveying roller 4 and the lower conveying roller 5 have two conveying rollers, and the upper conveying roller 4 is located downstream of the developing roller 2 in the developer conveying direction. Although the developing device in which the replenishing roller 3 is arranged so as to face the developing roller is described above, the developing device having such a configuration is replaced with one of the two conveying rollers which is located upstream of the developing roller 2 in the developer conveying direction. The replenishment roller 3 may be arranged so as to face the lower conveyance roller 5, or if there is only one conveyance roller, the replenishment roller 3 may be arranged so as to face the conveyance roller. Further, in the case of having three or more conveying rollers, the supply roller 3 may be arranged to face one of them.

Next, the driving means of the developing device of this embodiment will be described. In the developing device of FIG. 1 or 3, the developing roller 2, the upper and lower conveying rollers 4, 5 and the upper and lower stirring screws 6, 7 are driven by a gear arrangement as shown in FIG. The drive input from the drive means to the developing unit 1 is performed with respect to the shaft of the developing roller 2, and the driving force is transmitted to the lower conveying screw 7 and the upper conveying roller 4 via the idler gear 52 meshing with the developing roller gear 51, so that the developing operation is performed. It rotates in the same direction as the roller 2. In addition, the upper transport screw 6
Another idler gear for transmitting drive to the lower transport screw 7 is a two-stage gear. In the apparatus of this embodiment, the diameter of the developing roller 2 is larger than the diameter of the upper conveying roller 4, but the number of gear teeth is the same between the developing roller 2 and the upper conveying roller 4, and the developing roller 2 has the same number of teeth. The surface linear velocity is set to be higher than the surface linear velocity of the upper conveying roller 4. Therefore, the amount of the carrier pumped up is larger on the upper conveyance roller 4 than on the developing roller 2, and the replenishing roller 3 is directly opposed to the developing roller 2 to replenish the toner as compared with the conventional device. The contact area between the thin layer toner on the replenishing roller 3 and the carrier on the upper conveying roller 4 in the nip portion between the upper conveying roller 4 and the upper conveying roller 4 can be increased.

Next, the side plate pair of the developing unit 1 is connected to the side plate pair 3 of the developing agitating unit which supports at least the developing roller 2.
0, and a replenishment unit side plate pair 20 that positions and supports at least the replenishment roller 3 and the upper conveyance roller 4 that is disposed so as to face the replenishment roller 3, FIG. 4 shows a divided configuration when the present invention is applied. The replenishment unit side plate pair 20 constitutes a side wall of a toner storage chamber as a developer storage portion and holds each member in the toner storage chamber. That is, the supply roller 3, the blade holder 14, the agitator 11 and the like are detachably attached, and the right casing 16 and the upper cover 17 to which the supply roller seal 13 is attached are also detachably attached. Here, the pair of replenishment unit side plates 20, the replenishment roller 3, the replenishment roller seal 13 axially contacting the peripheral surface of the replenishment roller 3, the right casing 16, the upper cover 17, the blade holder 14, and the thinning blade 10. , The wall of the toner storage chamber. Further, the upper conveying roller 4 is supported so that the replenishing roller 3 is positioned by the same replenishing unit side plate pair 20.

The pair of side plates 30 of the developing and stirring unit constitutes a side wall of the developing and stirring chamber and holds each member in the developing and stirring chamber. That is, the developing roller 2, the transport roller 5,
The transport rollers 6 and 7, the screw casing 15, the developing doctor 8, the developer replenishing port cover 18, and the developing casing 19 are detachably attached.

Regarding the joining of the replenishing unit and the agitating unit, the pair of side plates 20 and 30 are butted against each other, and the joining is performed by a screw member (not shown).

According to the above construction, the replenishing unit side plate pair 2
0, the toner on the replenishing roller 3 and the upper conveying roller 4
Since it reduces the variation of the contact state with the upper carrier,
It is possible to stably supply the toner to the upper conveyance roller 4 without the toner conveyance ability varying. Further, the replenishing unit side plate pair 20 including the replenishing roller 3 and the developing roller 2
Regarding the joining of the developing stirring unit side plate pair 30 including the other unit, since the toner is not delivered in the gap between the developing roller 2 and the lower conveying roller 5, the strict gap accuracy as in the conventional apparatus is required. Instead, it is possible to configure a developing device that can be easily disassembled and joined by placing importance on workability during disassembly and joining. Therefore, it becomes possible to improve workability in cleaning and replacing the inside of the developing unit 1 as compared with the conventional apparatus. (Hereinafter, margin)

By the way, in the conventional developing unit 1, the thin layer toner on the replenishing roller 3 maintains a stable toner charge amount within a predetermined range so as not to cause image fogging due to insufficient charge of the developer after toner replenishment. Is required. Here, when the toner thin layer on the replenishing roller 3 is formed of one or more layers, the charging condition by the replenishing blade 10 is different between the inner layer and the outer layer, so that a stable charge amount can be maintained. Have difficulty. Therefore, from the viewpoint of uniformly charging the toner, it is desirable that the toner thin layer is formed to be one layer or less. However, under the condition that the toner thin layer is one layer or less, the upper limit of the amount of toner replenished onto the replenishing roller 3 is automatically determined depending on the toner particle size used, which is preferable from the viewpoint of improving the toner replenishing efficiency. Absent. Further, the toner thin layer on the replenishing roller 3 charged by the replenishing blade 10 is dispersed with a predetermined charge distribution with a certain charge amount as a peak, so that the toner having a relatively low charge amount is transferred to the developer side. It is difficult to replenish all the toner in the toner thin layer to the developer side because it is difficult to move. In particular, when the toner remains on the replenishing roller 3, the developer is already in a state of mainly retaining the replenished toner on the surface layer thereof, and the toner can be taken into the inside of the developer ear. However, it becomes more difficult to take in the residual toner.

Examples of the invention capable of preventing such a problem will be described below. FIG. 5 shows an example in which the present invention is applied to the conventional developing unit shown in FIG. In the developing unit 1, after passing through the developing area, the developer on the developing roller 2 is transferred to the lower conveying roller 5 containing a magnet.
Then, after being pulled up by the upper conveying roller 4, it is fed into the developing stirring chamber composed of the upper stirring screw 6 and the upper screw casing 6a, and the lower stirring screw 7 and the lower screw casing 7a. The replenishing roller 3 is installed so as to face the developing roller 2 and the lower conveying roller 5, and in the middle of the developer conveying path, the first replenishing area of the gap Gp1 and the second replenishing area of the gap Gp2 as shown in the figure. have. Here, the rotation directions of the developing roller 2 and the upper and lower conveying rollers 4 and 5 are as shown in FIG.
In the direction indicated by the arrow, and the moving direction of the thin layer toner on the surface of the replenishing roller 3 is opposite to the direction of the flow of the developer conveyed from the developing roller 2 to the upper and lower conveying rollers 4 and 5. Not drive the drive.

In the reversal developing method, the negatively charged toner forming a thin layer on the replenishing roller 3 has a potential difference (V _H -V _B ) between the developing bias V _B and the replenishing bias V _H in the first replenishing region, in the two supply regions by a potential difference between the conveying roller bias V _T and supply bias _{V H (V H -V T)} , the toner is supplied to the developer. The replenishment roller 3
To form a thin layer of toner on top, and to convey and stir the developer,
Since it is similar to the above-described conventional device, detailed description thereof will be omitted here.

In the configuration of this embodiment, the toner thinned on the replenishing roller 3 by the thinning blade 10 is opposed to the lower conveying roller 5 in the second replenishing area to replenish the toner to the developer. The toner remaining on the replenishing roller 3 as replenishment residue at that time replenishes the developer on the developing roller 2 with toner in the first replenishing area. Here, the drive input to the developing unit 1 by a driving device (not shown) is distributed to each roller and the screw by the drive gear train in the developing unit 1. In particular, in this modification, the lower conveyance roller 5 with respect to the surface linear velocity of the developing roller 2.
The number of rotations of each roller is set so that the surface linear velocity of is slow. As a result, the thickness of the developer layer in the second replenishment region becomes thicker and the nip becomes larger than in the first replenishment region of the developing roller 2, so that the toner replenishment rate in the second replenishment region is further improved. To do. In addition, reducing the surface linear velocity of the upper and lower conveying rollers 4, 5 means
Is smaller than the diameter of the developing roller 2 and has a large curvature, the developer nip with the replenishing roller 3 is small, and the developing in the second replenishing area is small because the magnet that can be incorporated is small. It also has an effect of correcting that the amount of toner replenishment becomes small due to the tendency of the agent spike to become small.

As described above, the upper and lower transport rollers 4,
In addition to setting the rotation speed of 5, the gap in the first replenishment region is set to be larger than the gap in the second replenishment region, and the contact area of the replenishment roller 3 with the developer is increased to increase the toner. The replenishment property can be improved. However, the surfaces of the upper and lower conveying rollers 4, 5 may be of a non-grooved type, or the surface magnetic force may be weak and the conveying force when the developer passes through the Gp2 portion of the conveying rollers 4, 5 may be reduced. In this case, the toner replenishment property may be improved by setting the gap in the second replenishment region to be larger than the gap in the first replenishment region. Of course, the adjustment of the size of the gap may be optimized as a developing device by combining with the above-described setting of each roller linear velocity.

Further, in this embodiment, the bias voltage applied to each roller is set so as to satisfy the condition of (V _H −V _B ) <(V _H −V _T ), that is, V _T <V _B. The electric field in the second replenishment region is made larger than that in the first replenishment region. This is because the replenishment bias V _H in the first replenishment region, to which a voltage higher than the development bias V _B must be applied, is as low as possible with respect to the development bias V _B which is determined by the development image forming state in the development region. In order to suppress the problem such as voltage leak when applying a high voltage and to simplify the structure of the power supply device, toner is stored in the first replenishment area where the developer concentration is lower than the second replenishment area. Prevents toner from rising into the chamber.

Further, in the first replenishment area, the bias applied to each roller satisfies the following expression for the toner having a strong adhesion to the replenishment roller 3 as the replenishment residual toner in the second replenishment area. Toner can be replenished more strongly by setting to. However, such setting may be changed depending on the carrier characteristics and the magnetic force configuration of the developing unit 1.
This can be performed under the condition that the carrier does not easily rise into the toner storage chamber.

FIG. 6 shows the developing unit 1 of FIG.
This is a modified example in which the above-mentioned problems can be prevented. The replenishment roller 3 is disposed so as to face the lower conveyance roller 5 and the upper conveyance roller 4, and each has a replenishment region of the gap Gp3 and a replenishment region of the gap Gp4. In particular, in the developing unit 1 of FIG. 6, unlike the developing unit 1 of FIG. 5, the developing bias applied to the developing roller 2 is not related to the replenishing bias applied to the replenishing roller 3, so that the developing bias V _B is less than the developing bias V _B. it is not necessary to determine the supply bias V _H so as to have a predetermined supply potential Te, it can be set low supply bias V _H as compared to the apparatus of FIG. Further, the replenishment potential formed by the lower conveyance roller bias V _T1 and the replenishment bias V _H in the first replenishment region is (V _H −V _T1 ), and the upper conveyance roller bias V _T 2 and the replenishment bias V V in the second replenishment region are _The replenishment potential formed by the difference from _H is (V _H −V _T 2), but here the upper transport roller bias V _T 2 is grounded at V _T 0, that is, GND. Therefore, the bias is (V _H −V _T 1) <(V _H −
By applying so as to satisfy the condition of V _T 0), that is, V _T 0 <V _T 1, the same tendency as that of the device of FIG. 5 can be provided and the power supply device can be downsized. . It should be noted that the upper transport roller bias V _T 2 in the developing unit 1 may of course be applied with a voltage.

According to each of the above-described modifications, the toner replenishment rate is improved in order to improve the followability to the developed image having a large amount of adhered toner. Therefore, when the rotation speed of the replenishing roller 3 is simply set high. In contrast, problems such as toner sticking to the replenishing blade 10 due to frictional heat on the blade, toner filming on the surface of the replenishing roller 3 and abrasion of the replenishing roller surface are not caused. Therefore, a toner thin layer defect due to use with time at a high rotation speed does not occur, and a good developed image can be maintained.

[0062]

According to the developing device of the first aspect, it is not necessary to dispose the replenishing member facing the developer carrying member as in the conventional device. Therefore, the degree of freedom in the layout configuration of the developing device can be increased. it can. The following advantages can be obtained by increasing the degree of freedom in layout configuration. For example, when rotating at high speed, problems will occur,
Even when the diameter of the replenishment member cannot be reduced, only the developer bearing member can be reduced in diameter, so that the driving torque of the developer bearing member and the power consumption can be reduced. The developing device can be downsized by downsizing the driving device and the power supply device. Further, for example, even if the magnet disposed inside the developer bearing member has a deviation in polar angle or a variation in surface magnetic force, the developer is less likely to adhere to the replenishing member, so that the toner is stored. It is possible to reduce the risk that the developer will reach the portion to be covered. Further, in setting the magnetic force distribution of the developer carrying member, since the surface magnetic force of the magnetic pole facing the replenishment member only needs to contribute to the conveyance of the developer, a strong magnetic force is not required unlike the conventional apparatus. Therefore, the number of parameters to be considered in setting the magnetic force distribution is reduced, and the setting is facilitated.

According to the developing device of the second aspect, since the variation in the contact state between the toner on the replenishing member and the carrier on the conveying member is reduced, there is no variation in the toner conveying ability and the toner can be stably conveyed to the conveying member. The supplied toner can be replenished. Further, regarding the joining with the other unit including the developer carrying member, the gap between the developer carrying member and the conveying member does not require strict gap accuracy as in the conventional device, and therefore work at the time of disassembling and joining is performed. By placing a developing device capable of disassembling and joining the unit including the developer carrying member and the unit including at least the replenishing member and the conveying member, the replenishing member that requires strict accuracy. It can be easily disassembled and joined while maintaining the gap with the carrying member. Therefore, it is possible to improve workability in cleaning and replacing the inside of the developing device, as compared with the conventional device.

According to the developing device of the third aspect, the driving means is arranged so that the surface linear velocity of the conveying member moves from the replenishing member to the conveying member according to the amount of the developer pumped up on the developer carrying member. Since the driving is performed so as to optimize the toner replenishment efficiency, a stable amount of toner can be replenished to the conveying member side according to the amount of developer on the developer carrier.

According to the developing device of the fourth aspect, the electric field between the replenishing member and the conveying member facilitates the replenishment of toner from the replenishing member to the conveying member, and also a stable amount of toner is supplied. Can be replenished.

According to the developing device of the fifth aspect, a means for changing the developing bias in accordance with the change of the developing bias is required by applying a fixed bias to at least one of the replenishing member and the conveying member. Therefore, the power supply device and the bias applying means can be simplified.

According to the developing device of the sixth aspect, it is sufficient that a bias having a predetermined potential for moving the toner is applied to the replenishing member or the conveying member. Therefore, the absolute value is larger than the developing bias. Can be applied. Therefore, by lowering the voltage, the power supply device can be simplified and
There are advantages such as measures against bias voltage leakage, simplification of the device in terms of safety, and increased freedom of layout.

According to the developing device of claim 7, one of the conveying member and the replenishing member is grounded, and the toner is moved from the replenishing member to the conveying member between both members. Since the potential gradient is provided, the power supply device can be downsized, and the device can be simplified in terms of safety such as measures against leakage of the bias voltage on the grounded side, and the flexibility of layout is increased. Occurs.

According to the developing device of claim 8, abnormalities such as image omission and toner replenishment failure due to bias leak do not occur, so that a developed image of stable quality can be obtained.

According to the developing device of the ninth aspect, since the toner is delivered by the magnetic force to the two-component developer at two positions, the first replenishing region and the second replenishing region on the replenishing member, the conveyance is performed. It is possible to provide a developing device capable of improving the efficiency of toner replenishment to the developer without driving the member at a high rotation speed. Further, at the time of this toner delivery, the toner is dispersed in the developer as the developer is peeled off from the replenishing member. Therefore, after the toner is replenished in the first replenishment region, the vicinity of the surface layer of the developer and the vicinity of the inner surface layer Since the non-uniformity of the toner concentration in the developer in (3) is alleviated, the toner replenishment efficiency in the second replenishment region can be further enhanced. Further, by increasing the toner replenishment efficiency in this way, it is possible to improve the replenishment followability of the toner to a high-adhesion image and to reduce the surface linear velocity of the replenishment member as compared with the conventional apparatus. Over time, for example, toner adhesion to a toner thinning member for replenishment and deterioration of the replenishment member are reduced, the life of the toner replenishment portion is extended, and the developing device is downsized by reducing the diameter of the replenishment member. Will be possible.

According to the developing device of the tenth aspect, the toner concentration of the developer in the first developing area is lowered after passing through the developing area, and the amount of toner adhered on the replenishing member is small due to the replenishment residue. Even in this case, the toner easily moves into the developer. Therefore, the toner replenishment efficiency can be further enhanced as compared with the case where the replenishment member is driven so as to rotate in the forward direction with respect to the developer transport direction.

According to the developing device of the eleventh aspect, the linear velocity ratio of the developer carrying member for obtaining the maximum toner replenishing efficiency to the developer on the developer carrying member is set to the line of the replenishing member. Since it is possible to set the respective optimum linear velocity ratios different from the speed ratio, the linear velocity condition of the conveying member is not restricted by the above-mentioned restriction of the replenishing member, and the degree of freedom can be set regarding the toner replenishment property. Can be higher.

According to the developing device of the twelfth aspect, in the gap between the replenishing member and the developer carrying member or the conveying member which is arranged so as to face the replenishing member, the difference in the developer conveying ability and the developer layer. Depending on the difference in thickness, the optimum gaps are set for different ones.Therefore, as in the case where the gap is set constant without considering these differences, the retention of the developer and the carrier to the toner storage unit There is no rise. Thereby, a stable developed image can be always provided.

According to the developing device of the thirteenth aspect, the bias optimized in consideration of the toner replenishing efficiency and the like is applied to the developer carrying member and the carrying member, respectively.
Since the replenishment bias does not have to have a predetermined potential based on the development bias, it is possible to improve the toner replenishment efficiency without applying the replenishment bias at a higher voltage than the development bias, as compared with the conventional apparatus.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of a developing device according to an embodiment.

FIG. 2 is an explanatory view showing a driving state of members in the developing device.

FIG. 3 is an explanatory view showing a state in which an upper conveyance roller is grounded.

FIG. 4 is a developing device according to another embodiment in which a replenishing unit side plate pair 20 and a developing stirring unit side plate pair 3 which are two pairs of side plates.
Explanatory drawing of the state isolate | separated into 0 and.

FIG. 5 is a front view showing a schematic configuration according to an embodiment in which a conventional developing device is improved.

FIG. 6 is a front view showing a schematic configuration according to a modified example of the apparatus of this embodiment.

FIG. 7 is a front view showing a schematic configuration of a conventional developing device.

FIG. 8 is a replenishing unit side plate pair 20 and a developing stirring unit side plate pair 30 in which the developing device according to the conventional apparatus is a pair of side plates.
Explanatory drawing of the state isolate | separated into and.

[Explanation of symbols]

 1 Developing Unit 2 Developing Roller 3 Toner Replenishing Roller 4,5 Vertical Conveying Roller 6,7 Vertical Stirring Screw 6a, 7a Screw Casing 8 Developing Blade 9 Toner Supplying Roller 10 Thinning Blade 11 Agitator 13 Replenishing Roller Seal 14 Blade Holder 18 Replenishing Port cover 20 Supply unit side plate pair 30 Development stirring unit side plate pair 31 Bearing mounting hole 51 Development roller gear 52 Idler gear 53 Upper conveyance roller gear 54 Lower conveyance roller gear 55 Two-stage idler gear 56 Upper stirring screw gear 57 Lower stirring screw gear

Claims (13)

[Claims] 1. A developer carrying member having a magnet therein and carrying a two-component developer comprising a toner and a carrier, a stirring member for stirring and mixing the two-component developer, and a magnet inside. A carrying member for carrying the developer on the developer carrying member to the stirring member side, a replenishing member for replenishing the toner, the developer carrying member, the stirring member, the carrying member, and A developing device having a driving means for driving the replenishing member, wherein the replenishing member is arranged in proximity to or in contact with a conveying member so as to face it. 2. A pair of side plates of the developing device includes a first side plate pair that supports at least the developer carrying member, and a second side plate pair that positions and supports at least the transport member and the replenishment member. The developing device according to claim 1, wherein: 3. The surface linear velocity of the conveying member facing the replenishing member satisfies a predetermined toner replenishing efficiency in accordance with the amount of the developer carried on the developer carrying member by the driving means. The developing device according to claim 1, wherein the developing device is configured so as to be driven. 4. A bias applying means for applying a bias to at least one of the replenishing member and the conveying member in order to accelerate the toner supply from the replenishing member to the conveying member facing the replenishing member. The developing device according to claim 1, wherein: 5. The bias applying means sets a fixed bias to at least one of a bias applied to the conveying member and a bias applied to the replenishing member, and the bias by the applying means is developed by another system. 5. The developing device according to claim 4, wherein the bias is variably controllable by applying it to the agent carrier. 6. The developing device according to claim 4, wherein the absolute value of the bias voltage is set smaller than the absolute value of the average voltage applied to the developer carrying member. 7. The developing device according to claim 5, wherein either one of the conveying member and the replenishing member is grounded. 8. The transport member comprises a first transport roller for transporting a developer and a second transport roller for transporting the developer to the stirring means, and the first transport roller is for developing the developer. The replenishment member is disposed so as to face the agent carrier and face the second transport roller so as to face the first transport roller and to face the replenishment roller. And a bias having a potential difference that promotes toner supply from the replenishment member side to the second conveyance roller side, is applied to at least one of the second conveyance roller and the second conveyance roller facing the replenishment member. The developing device according to claim 1, wherein the first transport roller is configured to be electrically floated. 9. A developer carrying member having a magnet inside and carrying a two-component developer comprising a toner and a carrier, a stirring member for stirring and mixing the two-component developer, and a magnet inside. A carrying member for carrying the developer on the developer carrying member to the stirring member side, a replenishing member for replenishing the toner, the developer carrying member, the stirring member, the carrying member, and In a developing device having a driving unit for driving the replenishment member, the replenishment member is provided on a first replenishment region facing the developer on the developer carrier so as to approach or contact the developer. And a second replenishment region facing the developer so as to be close to or in contact with the developer, and between the replenishment member and the developer carrier, and between the replenishment member and the transport member. From the replenishing member to the developer carrying member or the carrying member. And a replenishing bias applying means for applying a replenishing bias having a potential difference that promotes toner supply to the developer. 10. The driving means is driven so that the surface of the replenishing member and the surface of the developer carrying member or the conveying member arranged to face the replenishing member move in opposite directions at the facing portions. 9. The structure according to claim 8,
Or the developing device of 9. 11. A linear velocity ratio between the replenishing member and the developer in the first replenishing area and a linear velocity ratio between the replenishing member and the developer in the second replenishing area. 10. The developing device according to claim 8, wherein the developing device and the driving device are configured to be driven differently from each other. 12. The developing device according to claim 8, wherein gaps between the replenishing member and a plurality of members facing the replenishing member are different from each other. 13. The developing device according to claim 9, wherein the bias applying means is configured such that the bias applied to the developer carrying member and the bias applied to the conveying member are different from each other. .