JP4465959B2 - Developing device and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device, and more particularly to a developing device using a two-component developer in an image forming apparatus.
[0002]
[Prior art]
An image forming apparatus such as a copying machine or a printer using an electrophotographic method uniformly charges a photosensitive member configured in a drum shape, for example, and exposes the photosensitive member with light controlled based on image information. An electrostatic latent image is formed on the photosensitive member, the electrostatic latent image is made visible with toner, and the visible image is transferred to a recording sheet and fixed to form an image.
As a developing device used in such an image forming apparatus, a one-component developing device using magnetic toner and a two-component developing device using a two-component developer in which toner and a magnetic carrier are mixed are used. In an image forming apparatus, a two-component developing device is mainly used because it is necessary to use color toner.
[0003]
In the two-component developing device, it is necessary to maintain a constant toner density with respect to the magnetic carrier in order to ensure a constant image density and prevent fogging. For this purpose, a sensor that utilizes the fact that the magnetic permeability of the developer varies depending on the toner concentration and a sensor that utilizes the fact that the optical reflection density on the developer varies depending on the toner concentration are always detected and the toner concentration is detected. The toner density is kept constant by controlling the replenishment of toner based on the result.
[0004]
Here, as a conventional technique, the output fluctuation amount of the toner density sensor is obtained from the driving time of the developing device and the toner density detected by the toner density sensor, and the toner density detection value is corrected using the output fluctuation amount to form an image. There is a technique for detecting the toner density of the developing device in (see, for example, Patent Document 1). Further, there is a technique for performing toner replenishment control based on a detection result from a toner concentration detection sensor that detects a toner concentration of a two-component developer as a change in magnetic permeability (for example, see Patent Document 2).
[0005]
[Patent Document 1]
JP-A-7-234582 (page 7-8, FIG. 1)
[Patent Document 2]
JP-A-8-146751 (page 5-7, FIG. 1)
[0006]
[Problems to be solved by the invention]
However, in the conventional two-component developing device, in order to maintain the toner density constant, a toner density sensor, a control circuit that controls toner supply based on the detected toner density, and further toner supply. Therefore, there is a technical problem that it is difficult to reduce the size of the developing device and increase the cost.
[0007]
Note that the techniques described in Patent Document 1 and Patent Document 2 described above do not disclose an effective technique for controlling the toner density to be constant without using a toner density sensor, a toner supply control circuit, or the like.
[0008]
Accordingly, the present invention has been made based on such a technical problem, and an object of the present invention is to provide a developing device capable of automatically controlling the toner concentration of a two-component developer. It is in.
[0009]
[Means for Solving the Problems]
For this purpose, the developing device according to the present invention is provided with a toner supply path for supplying toner to a developer holding container for holding a two-component developer, and the developer to the toner supply path due to fluctuations in the toner concentration of the developer. The amount of intrusion is configured to change. As a result, the toner concentration of the two-component developer can be automatically controlled.
[0010]
That is, the developing device of the present invention includes a developer holding container that holds a developer composed of toner and a carrier, and a toner supply path that supplies the toner to the developer holding container. A feature is that the amount of the developer entering the toner supply path is changed by the change in the toner density. Further, the developer holding container can be characterized by being filled with a developer having an appropriate toner concentration which is substantially the same as the capacity of the developer holding container. Further, the amount of the developer entering the toner supply path is cut off when the developer is higher than the appropriate toner concentration, and the toner supply is enabled when the developer is lower than the appropriate toner concentration. Can change. In addition, the toner supply path may be arranged above the transport member. Further, the toner supply path may be characterized in that a toner natural fall assisting member is disposed.
[0011]
In addition, the developing device of the present invention includes a developer holding container that holds a developer composed of toner and a carrier, a conveying member that stirs and conveys the developer in the developer holding container, and a toner in the developer holding container. And a conveying member is characterized in that the developer is allowed to enter the toner supply path due to a change in the toner concentration of the developer. Further, the conveying member may be characterized in that the developer conveying amount of the conveying member positioned below the toner supply path is set so that the developer enters the toner supply path. In particular, the conveying member can be characterized in that the conveying member positioned below the toner supply path has a large shaft diameter.
[0012]
Further, the present invention is regarded as an image forming apparatus, and a developer holding container that holds a developer composed of toner and a carrier, a toner holding member that holds toner, and toner is supplied from the toner holding member to the developer holding container. And a toner supply path, and the amount of toner supplied from the toner holding member to the developer holding container is controlled by changing the amount of the developer entering the toner supply path.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings. ◎ Embodiment 1
FIG. 1 is a cross-sectional view illustrating a developing device in the present embodiment. The developing device 20 includes a developer holding container for containing a developer, a support container 21 as a casing of the developing device 20, a developing sleeve 22 as a developer carrying member, a developing magnet 23 that attracts the developer to the developing sleeve 22, A blade 24 that regulates the layer thickness of the developer, two augers 25 and 26 that circulate in the longitudinal direction of the developing device 20 while stirring the developer, and a toner supply path 27 that supplies toner to the support container 21 are provided. Yes.
[0014]
The support container 21 has an opening toward the photosensitive drum 1, and a developer containing portion for containing a developer in which toner and a carrier that is magnetic particles are mixed is provided. The developer accommodating portion is divided into a developer accommodating portion 21 b and a developer accommodating portion 21 c by an accommodating portion wall 21 a provided in the longitudinal direction of the developing device 20.
An auger 25 is disposed in the developer accommodating portion 21b, and an auger 26 is disposed in the developer accommodating portion 21c. The accommodating portion wall 21a is not provided at both end portions of the developing device 20, and the developer accommodating portion 21b and the developer accommodating portion 21c are connected at the both end portions.
[0015]
The developing sleeve 22 is made of a nonmagnetic material such as aluminum or SUS, and is rotated in the direction of arrow A by a driving unit (not shown). A developing magnet 23 is included in the developing sleeve 22. The developing magnet 23 is provided with a plurality of magnetic poles in the circumferential direction, and the developer is attracted to the developing sleeve 22. Then, the developer sleeve 22 rotates to convey the developer held in the developer accommodating portion 21 b to the photosensitive drum 1. The developing magnet 23 may be rotated.
The blade 24 is made of a nonmagnetic material or a magnetic material, and regulates the layer thickness of the developer carried on the developing sleeve 22 to a certain amount. Thus, a predetermined amount of developer is uniformly supplied to the photosensitive drum 1 in the axial direction of the developing sleeve 22 to develop the electrostatic latent image formed on the photosensitive drum 1.
[0016]
Next, the auger 25 and the auger 26 will be described. FIG. 2 is a schematic plan view of the developing device 20. The auger 25 and the auger 26 are each provided with a screw around the shaft. The auger 25 and the auger 26 are rotated in opposite directions by driving means (not shown) to convey the toner and the carrier in opposite directions while stirring. Since the developer accommodating portion 21b and the developer accommodating portion 21c are connected at both ends of the developing device 20, the developer flows into each other, and the auger 25 and the auger 26 cause the developer accommodating portion 21b and the developer accommodating portion 21c. It is comprised so that it may circulate between.
FIG. 3 is a diagram for explaining the auger 25. FIG. 3A is a perspective view of the auger 25, and FIG. 3B shows an XX ′ cross section of the auger 25. The auger 25 is provided with screws having an interval of 25 mm around an axis having a diameter of 8 mm. The screw has a trapezoidal shape with a height of 4.5 mm, a base of 4.1 mm, and a top of 1 mm.
[0017]
A toner supply path 27 for supplying toner from a toner container (not shown) to the developer accommodating portion 21c is disposed above the central portion of the developer accommodating portion 21c. Here, the supply of toner from the toner supply path 27 to the developer accommodating portion 21c will be described.
The support container 21 is configured so that the volume of the developer is approximately the same as the weight ratio (TC) of the toner and the carrier in the developer with which the capacity of the support container 21 is filled is an appropriate value (for example, 8%). ing. Here, the capacity of the support container 21 refers to the substantial capacity of the support container 21, and refers to the capacity of an area where the developer can move within the developing device 20. The appropriate value of TC means an appropriate TC in which the developed image has a sufficient image density and does not cause fogging.
The developing device 20 is filled with a developer having an appropriate TC so as to fill the support container 21.
[0018]
Here, FIG. 4 is a diagram showing the relationship between the TC of the developer and the volume of the developer. FIG. 4 shows a case where measurement is performed with the developer loosened and a case where measurement is performed with the developer pushed in and tapped. In both the loose state and the tapping state, the developer TC has a linear relationship with the developer volume, and as the TC increases, the developer volume increases proportionally. Therefore, as shown in FIG. 5, when the developer TC increases from the appropriate value, the developer volume becomes larger than the volume of the support container 21. Conversely, when the developer TC decreases from the appropriate value, the development proceeds. The volume of the agent is smaller than the volume of the support container 21.
[0019]
With this configuration, in the toner supply path 27 disposed at the upper portion of the developer accommodating portion 21c, the developer enters the opening of the toner supply path 27 due to a change in the volume of the developer based on a change in the TC of the developer. There is a state in which the opening is blocked by the intrusion and a state in which the opening is not reached without reaching the opening of the toner supply path 27.
FIG. 6 is a diagram for explaining a rising state of the developer in the toner supply path 27 due to a change in the volume of the developer. As shown in FIG. 6A, when the toner is consumed and the TC of the developer becomes smaller than an appropriate value, the volume of the developer is reduced and the developer amount does not reach the toner supply path 27. The toner supply path 27 is opened. In this state, the toner is supplied to the developer through the toner supply path 27. When the TC of the developer increases again, the volume of the developer increases, and the developer fills the entire support container 21.
[0020]
When the toner is further supplied to the developer, as shown in FIG. 6B, the amount of the developer exceeds the capacity of the support container 21, so that the developer overflows into the toner supply path 27 and generates swell. . Since the rising of the developer generated in the toner supply path 27 is away from the auger 26, the conveying force by the auger 26 is weak. Therefore, the developer in the toner supply path 27 stays to form a developer wall, and the supply of toner from the toner supply path 27 to the developer is blocked. As a result, toner is not supplied to the developer, and the TC of the developer does not become higher than that.
[0021]
Further, when the toner is consumed and the TC of the developer decreases and the volume decreases, the developer in the toner supply path 27 does not rise, and the toner is supplied again through the toner supply path 27.
In this manner, the toner supply path 27 is blocked / opened by the change in the developer volume, whereby the supply of toner to the developer is controlled, and the TC of the developer can always be kept constant.
Therefore, it is preferable that the toner supply path 27 is disposed in an area where the volume change of the developer is large, and is disposed above the area where the auger 26 is disposed in the developer accommodating portion 21c.
[0022]
FIG. 7 is a diagram showing a change in TC when the developing device 20 is operated. In FIG. 7, the carrier amount is set to 300 g, the capacity of the support container 21 is set to be approximately the same as the volume when the carrier of 300 g becomes TC 8%, and the opening of the toner supply path 27 is configured to be 10 × 10 mm. . In FIG. 7, A shows a case where the developing device 20 is operated with the TC of the developer set to 0% as an initial setting. The developer is supplied with toner from the toner supply path 27, and TC rises rapidly and saturates at about 8%. In B, the recovery from the state where the developing operation is performed and the toner is rapidly consumed to reduce the TC is shown. As in A, the developer is supplied with toner and the TC rises rapidly and saturates at approximately 8%. In C, toner was forcibly supplied to the developer, and TC was set high. Thereafter, in D, the developing operation is performed and the toner is rapidly consumed. Even in this case, TC decreases with toner consumption, but TC increases rapidly and saturates at about 8%. As described above, in the present embodiment, the toner supply path 27 can sufficiently control the supply of toner by changing the volume of the developer, and can maintain the TC constant.
[0023]
Next, FIG. 8 is a diagram showing the toner supply speed when TC is lowered from the saturation TC of the developer. In FIG. 8, the horizontal axis represents the TC decrease value (%) from the saturated TC, and the vertical axis represents the toner supply speed (g / sec) in logarithmic display. As shown in FIG. 8, the toner supply speed increases dramatically as the TC value greatly decreases from the saturation TC value, and the toner supply speed decreases rapidly as the TC value approaches the saturation TC value. As described above, in this embodiment, when the TC value greatly decreases from the saturation TC value, the toner supply speed increases and TC is quickly recovered. As the TC value approaches the saturation TC value, the toner supply speed decreases rapidly and TC decreases. It is possible to stabilize to a saturated TC value.
[0024]
Note that the toner supply speed necessary for developing a solid black image is 0.096 g / sec. However, when a solid black image is output continuously, the TC decreases near the saturated TC and is lower than the saturated TC. The toner supply speed catches up with a TC lowered by 2 to 4%, and can follow a solid black image.
[0025]
Next, the carrier amount and the torque of the developing device 20 will be described.
FIG. 9 is a diagram showing the TC when the amount of carrier charged in the developing device 20 and the amount of carrier amount fluctuation lost due to the actual use of the developing device 20 are changed. In this case, the capacity of the support container 21 of the developing device 20 is also set to be almost the same as the carrier amount. The initial TC is set to 8%.
As shown in FIG. 9, TC changes by ± 2% when the amount of change in carrier amount changes by ± 10% with respect to the amount of charged carrier in any of the charged carrier amounts. For this reason, the larger the amount of the filled carrier, the smaller the influence on the TC with respect to the change in the absolute value of the carrier amount fluctuation amount. That is, if the amount of the filled carrier is large, the change in TC is small with respect to the absolute value of the carrier amount fluctuation. Therefore, the TC is stabilized as the amount of the filled carrier is larger.
[0026]
On the other hand, FIG. 10 is a diagram showing the relationship between the amount of carrier filled in the developing device 20 and the driving torque in that case. FIG. 10 shows the total torque of the entire developing device 20 and the total torque of the auger having a shaft diameter of 12 mm. As shown in FIG. 10, when the amount of the filled carrier is increased, the driving torque is also increased almost proportionally. When the drive torque increases, it becomes necessary to increase the amount of current supplied to the drive motor and to increase the rigidity of the support container 21. For this reason, it is preferable that the amount of the filled carrier is small from the viewpoint of driving torque.
Accordingly, the amount of the filled carrier is appropriately set in consideration of the stability of the TC and the driving torque, and as a result, the capacity of the support container 21 is configured to correspond to the amount of the filled carrier.
[0027]
Next, toner conveyance in the toner supply path 27 will be described. The toner supply path 27 connects a toner container (not shown) disposed above the developer container 21c and the developer container 21c, and forms a passage for supplying toner to the developer container 21c. Therefore, in a normal state, the toner is supplied by being naturally dropped from the toner container to the developer accommodating portion 21c.
[0028]
FIG. 11 is a diagram for explaining the drop assisting member disposed inside the toner supply path 27. Since the toner has high fluidity in a normal state, it can be naturally dropped from the toner container to the developer accommodating portion 21c. However, depending on the type of toner, the ambient temperature, the humidity, and the like, the fluidity may deteriorate, and the toner may block inside the toner supply path 27. When the toner is blocked, it is difficult to let it fall naturally. Therefore, the fall assisting member 30 is disposed inside the toner supply path 27, and the toner can be naturally dropped into the developer accommodating portion 21c by breaking the toner blocking.
[0029]
As shown in FIG. 11A, the drop assisting member 30 has a configuration in which plate-like fins 32 are arranged on a rotating shaft 31, and toner is blocked by the fins 32 by rotating the rotating shaft 31. It is something that breaks down. Further, the drop assisting member 30 may be configured such that a rod-shaped protrusion 33 is disposed on the rotating shaft 31 as shown in FIG.
[0030]
◎ Embodiment 2
In the first embodiment, the developer volume filled in the developing device 20 is configured such that the volume of the developer and the capacity of the support container 21 when the TC of the developer is an appropriate value are substantially the same, and the developer The developing device 20 that controls the supply of toner to the developer by the blocking / opening of the toner supply path 27 due to the change in volume of the toner has been described. In the second embodiment, the amount of developer to be filled in the developing device 20 is filled so that the volume when the TC of the developer is an appropriate value is smaller than the capacity of the support container 21, and the developer conveyance amount is increased. The developing device 20 that controls the supply of toner to the developer by causing the toner supply path 27 to be blocked / opened by the change in the volume of the developer will be described. In addition, about the structure similar to Embodiment 1, the same code | symbol is used and the detailed description is abbreviate | omitted here.
[0031]
First, the relationship between the developer transport amount of the augers 25 and 26 and the developer swell in the toner supply path 27 will be described. Increasing the diameter of the shafts of the augers 25, 26 increases the developer transport amount of the augers 25, 26. The augers 25 and 26 are transported while applying an outward force to the developer. Therefore, when the developer transport amount is increased, the amount of developer swell increases. Therefore, even if the developer having a proper TC is filled with an amount smaller than the capacity of the support container 21, the developer is supplied to the toner supply path 27 as the TC increases in the toner supply path 27. It is possible to cause the developer to swell so as to enter the surface.
[0032]
FIG. 12 is a diagram showing the relationship between the developer filling amount and the height of the developer rising in the toner supply path 27, and compares the augers with shaft diameters of 8 mm and 12 mm. As shown in FIG. 12, an auger having a shaft diameter of 12 mm can sufficiently obtain the rising height of the developer in the toner supply path 27 even with a small amount of carrier. In contrast, an auger with a shaft diameter of 8 mm requires a larger amount of carrier in order to obtain a sufficient height of developer in the toner supply path 27.
[0033]
In this way, by configuring the augers 25 and 26 so as to increase the developer conveyance amount, even if the developer filling amount is smaller than the capacity of the support container 21, the rising height of the developer in the toner supply path 27 is increased. Thus, the toner supply path 27 can be blocked / opened.
In particular, the auger 26 is configured so that the developer conveyance amount can be increased at the lower part of the toner supply path 27 to obtain a sufficient height of the developer. It is configured so that the amount of the agent is conveyed. With such a configuration, the developing device 20 that performs the function of blocking / opening the toner supply path 27 and at the same time allows the developer to freely move in the developer storage section 21 c other than the developer storage section 21 b and the lower portion of the toner supply path 27. Therefore, the driving torque of the developing device 20 can be reduced.
[0034]
Further, as shown in FIG. 13, the diameter of the shaft 26a at the lower part of the toner supply path 27 of the auger 26 is made thick so that the development in the developer accommodating portion 21c located at the lower part of the toner supply path 27 is achieved. Since the developer transport amount increases and the volume of the developer passage area decreases, the rising height of the developer in the toner supply path 27 is amplified, and the developer filling amount may be smaller than the capacity of the support container 21. A configuration capable of supplying toner with higher sensitivity to changes in TC can be realized.
[0035]
As described above, according to the present embodiment, the toner supply path 27 is blocked / opened by the volume change based on the change in the TC of the developer, and the toner supply to the developer is autonomously controlled. The TC of the developer can always be kept constant. Therefore, the developing device 20 can be configured without the need for a toner density sensor, a control circuit for controlling toner supply based on the detected toner density, and a toner supply mechanism for supplying toner. The developing device 20 can be reduced in size and can be manufactured at low cost.
[0036]
Next, FIG. 14 shows a color image forming apparatus using the developing device 20 in the present embodiment. The color image forming apparatus 40 is configured by arranging four photosensitive drums 1A, 1B, 1C, and 1D around the intermediate transfer belt 7. Each photosensitive drum 1A, 1B, 1C, 1D, for example, a charger 2A that uniformly charges the photosensitive drum 1A around the photosensitive drum 1A, and an LED that exposes light controlled based on image information A print head (LPH) 3A, a developing device 20A for developing a latent image formed on the photosensitive drum 1A, a primary transfer roller 12A for transferring a toner image to the intermediate transfer belt 7, and a transfer residual toner from the photosensitive drum 1A A cleaner 5A for removing the toner, a static eliminator 6A for removing the remaining charges on the photosensitive drum 1A, and a fixing device 11 for fixing the toner image on the recording paper 9 are provided. The periphery of the photosensitive drums 1B, 1C, and 1D is similarly configured.
[0037]
The charger 2A is formed by a charging roller configured by laminating conductive rubber or conductive sponge and conductive rubber, and is connected to a power source (not shown) to be supplied with voltage. The surface of the photosensitive drum 1A is uniformly charged with a constant voltage. The LPH 3A irradiates light controlled based on image data from a host computer (not shown) to form a latent image on the photosensitive drum 1A.
[0038]
The developing device 20A is configured similarly to the developing device 20 of the present embodiment. The latent image formed on the photosensitive drum 1A is developed with a developer using yellow (Y) toner to form a toner image. The developing device 20A can be miniaturized because it does not require a toner density sensor, a control circuit for controlling toner supply based on the detected toner density, and a toner supply mechanism for supplying toner. It can be manufactured at low cost.
The developing devices 20B, 20C, and 20D are also configured in the same manner as the developing device 20 of the present embodiment, and are developed with a developer using magenta (M), cyan (C), and black (K) toners, respectively. M, C, and K toner images are formed.
[0039]
The primary transfer roller 12A is configured by laminating conductive rubber or conductive sponge and conductive rubber, and is connected to a power source (not shown) and supplied with voltage. Then, the toner image is transferred onto the intermediate transfer belt 7. The cleaner 5A includes a cleaning blade and a cleaner housing. The cleaning blade is in contact with the rotating direction of the photosensitive drum 1A in the counter direction, scrapes off the transfer residual toner remaining on the photosensitive drum 1A at the time of transfer, and stores it in the cleaner housing.
[0040]
The static eliminator 6A is configured by laminating conductive rubber or conductive sponge and conductive rubber, and is connected to a power source (not shown) and supplied with voltage. Then, the electric charge remaining on the photosensitive drum 1A is removed, and the surface potential on the photosensitive drum 1A is made uniform to approximately 0V. The fixing device 11 includes a pair of rollers including a heating roller 11a and a pressure roller 11b. The recording paper 9 onto which the toner image has been transferred is conveyed to the fixing device 11 by the conveying belt 10, and when passing through the fixing device 11, the toner image is heat-fixed on the recording paper 9.
[0041]
The intermediate transfer belt 7 is made of a flexible film such as polyimide, and moves while being held between the photosensitive drums 1A, 1B, 1C, and 1D and the primary transfer rollers 12A, 12B, 12C, and 12D. The Y, M, C, and K toner images formed on the respective photosensitive drums 1A, 1B, 1C, and 1D are aligned by the registration sensor 8 by the primary transfer rollers 12A, 12B, 12C, and 12D, respectively. It is transferred onto the intermediate transfer belt 7 and synthesized.
[0042]
The color toner image transferred and synthesized on the intermediate transfer belt 7 is collectively transferred to the recording paper 9 by the secondary transfer roller 13. Then, the paper is transported to the fixing device 11 by the paper transport belt 10 and fixed on the recording paper 9 to form a color image. The toner remaining as a transfer residue on the intermediate transfer belt 7 is removed by the cleaner 14.
[0043]
By using the developing device 20 in the present embodiment for such a color image forming apparatus, the overall configuration of the color image forming apparatus can be reduced in size, and the cost can be reduced in manufacturing.
[0044]
【The invention's effect】
As described above, according to the present invention, the toner concentration of the two-component developer can be automatically controlled.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a developing device.
FIG. 2 is a schematic plan view of a developing device.
3A and 3B are diagrams illustrating an auger, in which FIG. 3A is a perspective view of the auger, and FIG. 3B is an XX ′ cross section of the auger.
FIG. 4 is a diagram showing the relationship between the TC of the developer and the volume of the developer.
FIG. 5 is a diagram illustrating a relationship between a developer volume and a support container volume;
FIG. 6 is a diagram illustrating a rising state of a developer in a toner supply path due to a change in developer volume.
FIG. 7 is a diagram showing a change in TC when the developing device is operated.
FIG. 8 is a diagram illustrating a toner supply speed when TC is lowered from saturated TC of a developer.
FIG. 9 is a diagram showing TC when the carrier amount and the carrier amount fluctuation amount are changed.
FIG. 10 is a diagram showing the relationship between the carrier amount and the driving torque.
FIG. 11 is a diagram illustrating a drop assisting member.
FIG. 12 is a diagram illustrating a relationship between a developer filling amount and a rising height of a developer in a toner supply path.
FIG. 13 is a diagram illustrating a configuration of an auger.
FIG. 14 is a diagram illustrating a configuration of a color image forming apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 20 ... Developing device, 21 ... Support container, 21a ... Housing part wall, 21b, 21c ... Developer accommodating part, 22 ... Developing sleeve, 23 ... Developing magnet, 24 ... Blade, 25, 26 ... Auger, 27 ... Toner supply path

Claims (3)

A developer holding container for holding a developer composed of a toner and a carrier, and supplying the developer to a developer carrying member that conveys the developer to a photoreceptor;
The developer holding container has an opening for supplying the toner, and the opening is blocked by a volume change based on a change in the weight ratio of the developer toner and the carrier held in the developer holding container. And a toner supply path arranged at a position set to an open state,
A shaft disposed inside the developer holding container and having an outer diameter in a region where the opening of the toner supply path is located is larger than an outer diameter in a region where the opening is not located, and provided around the shaft The developer is transported while being agitated by the screw, and the volume of the developer passage region in the region where the opening is located is set smaller than the volume of the passage region in the region where the opening is not located. And a conveying member.   The toner supply path is set to the blocked state when the opening is higher in the developer than the predetermined toner concentration, and the opening is opened when the developer is lower than the predetermined toner concentration. The developing device according to claim 1, wherein the developing device is disposed at a position where the state is set. A photoreceptor,
A developing device for developing the latent image formed on the photoconductor,
The developing device includes:
A developer holding container for holding a developer composed of a toner and a carrier, and supplying the developer to a developer carrying member that conveys the developer to a photoreceptor;
The developer holding container has an opening for supplying the toner, and the opening is blocked by a volume change based on a change in the weight ratio of the developer toner and the carrier held in the developer holding container. And a toner supply path arranged at a position set to an open state,
A shaft disposed inside the developer holding container and having an outer diameter in a region where the opening of the toner supply path is located is larger than an outer diameter in a region where the opening is not located, and provided around the shaft The developer is transported while being agitated by the screw, and the volume of the developer passage region in the region where the opening is located is set smaller than the volume of the passage region in the region where the opening is not located. An image forming apparatus comprising: a conveying member.

Images