JP2000066499A - Developing device and image forming device adopting same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of obtaining an excellent image, even though a distance or the like between the developer carrier and the image carrier is remarkably changed, or the environment of a device inside is varied. SOLUTION: This developing device 104 is, provided with a developing roller 117 for performing the developing operation by feeding toner G1 on a photoreceptor drum 102, and the feeding roller 119 for feeding the toner G1 on the developing roller 117. The developing device 104 is provided with a density sensor 130 for detecting the development result, and a controller 140 for controlling the developing device 104 is, allowed to change rotary speed of the feeding roller 119, based on the output result of the density sensor 130.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for, for example, a mono-color or full-color copying machine or printer, and an image forming apparatus using the same. More specifically, a developing device capable of obtaining a good image even if the separation distance between the developer carrier and the image carrier significantly changes, or the environmental condition in the above-described device changes. And an image forming apparatus using the same.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, an electrostatic latent image is formed on a photosensitive drum that has been charged over its entire surface by exposure of an optical writing unit, and then a developing blade is used to regulate the amount of developer carried by a developing roller. Then, the developer is adhered to the electrostatic latent image on the photosensitive drum to visualize the image and form an image on recording paper. Both the developing roller and the photosensitive drum are composed of cylindrical rotating bodies,
The distance between the photosensitive drum and the developing roller may fluctuate. When such a change occurs, the development efficiency also varies, and the quality of an image formed on a recording sheet also deteriorates. Therefore, for example, in Japanese Patent Application Laid-Open No. 4-350864, a change in the distance between the photosensitive drum and the developing roller is changed.
The correction is made by adjusting the developing voltage applied to the photosensitive drum and the developing roller. Further, for example, Japanese Patent Application Laid-Open
In Japanese Patent No. 72880, in order to cope with fluctuations in the interval between the photosensitive drum and the developing roller, any one of a charging intensity of a charger, a magnitude of a bias voltage, a frequency of an AC bias voltage, and a light intensity of a light source, or a combination thereof is used. I am adjusting it.

[0003]

However, Japanese Unexamined Patent Publication No.
In the technology disclosed in Japanese Patent Publication No. 350864 and Japanese Patent Application Laid-Open No. 5-72880, the range that can be corrected is unexpectedly narrow. For this reason, it easily occurs that the variation in the distance between the photosensitive drum and the developing roller deviates from the assumed range and exceeds the correctable range. In addition, the development result of the components such as the developing roller significantly decreases at the end of a period in which the component can be used normally (hereinafter referred to as a “durable period”) or due to an environmental change in the apparatus. On the other hand, for example, Japanese Patent Application Laid-Open No. 5-72
The technique disclosed in Japanese Patent Publication No. 880 or the like cannot cope with the problem. Therefore, the density of the image formed on the recording paper may be reduced, or the image may be lost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the distance between the developer carrier and the image carrier is significantly changed, and the environment inside the apparatus is changed. It is an object of the present invention to provide a developing device capable of obtaining a good image and an image forming apparatus using the same.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a developer carrier for supplying a developer to an image carrier and performing a developing operation; In a developing device having a supply unit for supplying, a detection unit for detecting development efficiency and a control unit for changing a supply condition of the supply unit based on a detection result of the detection unit are provided. In this invention, the detecting means detects the development efficiency,
The control means can change the supply condition of the supply means based on the detection result. Thus, even if a change in the separation distance between the developer carrier and the image carrier, a change in the environment, a change in the development state at the end of the endurance period, and the like occur, the supply unit is based on the detection result of the development efficiency. By changing the supply conditions, it is possible to sufficiently cope with the situation and obtain a good image. Here, the “development efficiency” means the ratio of “the supply of the developer by the supply unit of the developing device” to the “development result of the developer supplied to the image carrier”. Not limited to "developer concentration on the image carrier" as
Factors that affect the development result, such as the amount of the developer deposited on the developer carrier, the distance between the image carrier and the developer carrier, and the environmental condition in the developing device. May be.

In this developing device, the supply conditions of the supply unit include a rotation speed of the supply unit, a position of the supply unit, a voltage applied to the supply unit, a diameter of the supply unit, and a contact pressure of the supply unit. And at least one of the contact width. When these supply conditions are changed, the development results of the developer supplied to the image carrier are affected.Therefore, by changing the supply conditions based on the detection result of the development efficiency, the developer carrier and the developer carrier are changed. It can sufficiently cope with changes in the separation distance and the like from the image carrier,
Good images can be obtained.

In this developing device, it is preferable that the supply means has a supply roller, and the control means controls the rotation speed of the supply roller. When the rotation speed of the supply roller is controlled as described above, the development result of the developer supplied to the image carrier is affected. For example, when the rotation speed of the supply roller increases, the supply amount of the developer increases, and the image density of the developer increases. On the other hand, when the rotation speed of the supply roller decreases, the supply amount of the developer decreases. As a result, the image density of the developer decreases. Therefore, the present invention sufficiently responds to a change in the separation distance between the developer carrier and the image carrier by changing the rotation speed of the supply roller based on the detection result of the development efficiency. And a good image can be obtained.

In this developing device, it is preferable that the supply means has a supply roller and the control means controls the diameter of the supply roller. When the diameter of the supply roller is controlled in this manner, the development result of the developer supplied to the image carrier is affected, and the image density of the developer is increased or decreased. Therefore, the present invention can sufficiently cope with a change in the separation distance between the developer carrier and the image carrier by controlling the diameter of the supply roller based on the detection result of the development efficiency. And good images can be obtained.

In this developing device, it is preferable that the supply means includes a supply roller and a regulating blade facing the supply roller, and the control means controls a positional relationship between the supply roller and the regulation blade and an applied voltage. Alternatively, it is preferable that the supply unit includes a supply roller and a regulating blade that comes into contact with the supply roller, and the control unit controls a contact pressure or a contact width therebetween. When the positional relationship between the supply roller and the regulation blade, the contact pressure or the contact width between the supply roller and the regulation blade, and the applied voltage applied between the supply roller and the regulation blade are changed, the development supplied to the image carrier is changed. This affects the development result of the developer, and the image density of the developer supplied to the image carrier increases or decreases, so that these can be controlled based on the detection result of the development efficiency. Therefore, the present invention can sufficiently cope with a change in the separation distance between the developer carrying member and the image carrying member, and can obtain a good image.

The detecting means includes: an amount of the developer adhering on the developer carrier; a distance between the image carrier and the developer carrier; an environmental condition in the developing device; At least one of the remaining periods that can be used for the remaining period). As a result, the amount of the developer attached to the developer carrier is increased or decreased, the distance between the image carrier and the developer carrier is shifted, the environmental condition in the developing device is changed, or the endurance period is reduced. Even if the end is approaching, the amount of the developer attached on the developer carrier, the distance between the image carrier and the developer carrier, the environmental state in the developing device, the remaining life of the developing device, etc. are detected, The control unit can change the supply condition of the developer supply unit based on the detection result. Therefore, the present invention can cope with a change in the separation distance between the developer carrier and the image carrier, and can obtain a good image.

According to another aspect of the present invention, there is provided an image forming apparatus including the above-described developing device, an image carrier for carrying an image, and an image forming means for forming an image on the image carrier. ing. In this image forming apparatus, an image is formed on an image carrier by an image forming unit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying a developing device of the present invention and an image forming apparatus using the same will be described below in detail with reference to the drawings. In the present embodiment, in an electrophotographic image forming apparatus, an image is formed using a nonmagnetic one-component toner developer (hereinafter, simply referred to as toner G1). FIG. 1 is a schematic diagram illustrating a main part of the image forming apparatus according to the embodiment.

As shown in FIG. 1, an organic photoconductive material (OPC) is provided at a substantially central portion in the main body 101 of the image forming apparatus.
Drum 102 having a thin film layer formed of
(Image carrier) is provided rotatably in the direction of arrow A. Around the photosensitive drum 102, a charger 103, a developing device 104, a transfer device 105, and a cleaner 106 are sequentially arranged along the rotation direction of the arrow A, and further, an obliquely upper side of the photosensitive drum 102. Is provided with a laser exposure device 107 as an image forming means. A controller 140 (control means) of the image forming apparatus is provided on a bottom side of the apparatus main body 101. The controller 140 includes a charger 103, a developing device 104, a transfer device 105, a cleaner 106, a laser The exposure device 107 and the like can be controlled.

The charger 103 uniformly charges the entire surface of the thin film layer on the surface of the photosensitive drum 102 while rotating the thin film layer in the direction of arrow A. Further, the laser exposure device 107
Exposes the surface of the photoconductor drum 102 with a laser beam 115 based on image information, thereby forming an electrostatic latent image on the photoconductor drum 10.
2 formed on the surface. In order to form the image information, a reading device IR for reading image information on a document is provided above the image forming apparatus main body 101. Based on the image information read by the reading device IR, the controller 140 Data for driving the laser exposure device 107 is created. In this case, the surface potential of the photosensitive drum 102 that has received the laser beam 115 is greatly different between the image portion where the electrostatic latent image is formed and the non-image portion where the electrostatic latent image is not formed, and the negatively charged toner G1 Is visualized only in the image portion where the electrostatic latent image is formed, corresponding to the electrostatic latent image.

The developing device 104 visualizes the latent image formed on the photosensitive drum 102 by using the toner G1, and rotates in the direction of arrow C at a position adjacent to the photosensitive drum 102. A developing roller 117 (developer carrier) is provided. Further, the developing device 104 has a toner hopper 116 for storing the toner G1, and a regulating blade 118 (regulating member) extending toward the developing roller 117 is disposed above the toner hopper 116. Then, the developing roller 117 of the toner hopper 116
A supply / recovery roller (hereinafter, simply referred to as a supply roller) 119 as a supply / recovery unit for the toner G1 is disposed in the buffer chamber 116a located on the side. Further, a toner storage chamber 116 located on the back side of the toner hopper 116 is provided.
b has stirring blades 120 that rotate in the direction of arrow B to agitate the toner G1 and supply the toner G1 to the supply roller 119. The developing roller 1
17, a lower seal 121 (static elimination member) that comes into contact with the developing roller 117 is provided below. The photosensitive drum 1 is located between the photosensitive drum 102 and the developing roller 117.
There is provided a density sensor 130 (density detecting means) for detecting the density of the toner G1 attached to the surface 02.

These components will be described in detail. The supply roller 119 rotates while rotating in the direction of arrow D (the same direction as the direction of arrow C) in contact with the developing roller 117.
1 can be supplied to the developing roller 117, so that the regulating blade 118 rotates in the direction of rotation of the developing roller 117 (arrow C).
), The developing roller 117 contacts the developing roller 117 on the downstream side, and the thickness of the thin layer of the toner G1 carried on the developing roller 117 is made constant. A power supply 114 is provided on the bottom side of the image forming apparatus main body 101. The power supply 114 applies a negative bias to the regulating blade 118 so that the toner G1 does not adhere to the regulating blade 118. Apply.

When supplying the toner G1 to the photosensitive drum 102, the developing roller 117
The toner G <b> 1 is applied to the photosensitive drum 102 while rotating in the direction indicated by the arrow C in a region (hereinafter referred to as a “developing region”) which is close to and opposes to the photosensitive drum 102. In this case, the developing roller 11
7 is made of a conductive material and is connected to the power supply 114 so that a developing bias voltage is appropriately applied. Therefore, when the developing bias voltage is applied to the developing roller 117, Is converted into a powder cloud in the developing area, and the photosensitive drum 1
Fly towards 02. During development, the power supply 1
Reference numeral 14 denotes a voltage difference of 1000 V to 3000 V so that an electric field in which the toner G1 travels is generated in a portion of the photosensitive drum 102 irradiated with the laser beam 115 from the developing roller 117.
V, a frequency of 1 to 10 kHz, a duty of 10 to 90% offset, and an AC bias of a voltage of −100 V to −800 V are applied.

The lower seal 121 is used to remove electricity by frictionally charging the toner G1 to a polarity opposite to the normal charging polarity of the toner G1. For the film, for example, a material having good conductivity in which carbon is kneaded is used. The power supply device 114 is connected to the supply roller 119 and a collection bias can be set between the developing roller 117 and the supply roller 119. Therefore, after the development operation is completed, the supply bias is set under the collection bias setting state. The roller 119 is a developing roller 11
7 can be collected. Specifically, at the time of collecting the toner G1 after the development, the voltage value of the supply roller 119 is set to be approximately 100 V higher than the voltage value of the developing roller 117.

A paper feed cassette 108 for storing the recording paper P is provided below the image forming apparatus main body 101, and a cutout for feeding the recording paper P is provided above the paper feed cassette 108. A feed roller 109 is provided.
The photosensitive drum 1 is provided above the sheet cassette 108.
02 is formed, and the recording paper P conveyed in the paper passage 110a is transported by the pair of paper feed rollers 110b to the photosensitive drum 102 and the transfer device 10a.
5 is led to the transfer region 113 sandwiched between the transfer region 5 and the transfer region 5. The transfer device 105 transfers the image of the toner G1 on the photosensitive drum 102 onto the recording paper P from the back side of the recording paper P sent in synchronization with the movement of the image of the toner G1 on the photosensitive drum 1. In the transfer region 113, a transfer charge of positive polarity opposite to the charge polarity of the toner G1 is given. As a result, the image of the toner G1 on the photosensitive drum 102 is transferred to the recording paper P, and an image is formed on the recording paper P.

On the downstream side of the transfer area 113, a paper guide 110c for guiding the recording paper P separated from the photosensitive drum 102 to the fixing unit 111 is provided, and further on the downstream side, the fixing unit 111 is provided. And the fixing device 111
Heat-fixes the image of the toner G1 transferred in the transfer area 113 onto the recording paper P. Then, the fixing device 111
The recording paper P sent to the discharge tray 11
2 is discharged.

The cleaner 106 is for removing the toner G1 remaining on the photosensitive drum 102 after the transfer, and has a cleaning blade 106a for removing the toner G1. As a result, the cleaning blade 106a scrapes the toner G1 on the photosensitive drum 102 while contacting the photosensitive drum 102 rotating in the direction A in FIG.
Is housed in the cleaner 106.

The controller 140 has a well-known CP.
It is a microcomputer that combines U, ROM, RAM, etc., and controls various devices in the image forming apparatus.
In particular, since the power supply 114 can be appropriately controlled,
The power supply device 114 includes the photosensitive drum 102 and the developing roller 1.
17, a bias voltage is appropriately applied to the supply roller 119, the lower seal 121, and the like.

Here, the case where the distance between the photosensitive drum 102 and the developing roller 117 changes will be specifically described with reference to FIG. FIG. 2 shows the photosensitive drum 102
Is a graph showing the relationship between the image density of the toner G1 attached to the image and the area ratio, where the image density is plotted on the vertical axis and the area rate (the ratio of the toner image within a predetermined area) is plotted on the horizontal axis. In addition, the image density increases as the area ratio increases. When the distance (for example, from 0.20 mm to 0.35 mm) between the photosensitive drum 102 and the developing roller 117 changes, a density difference occurs due to the distance.

Specifically, at point Q on the graph, the distance between the photosensitive drum 102 and the developing roller 117 is 0.20.
mm and 0.30 mm, a density difference of about 0.15 occurs. That is, the developing device 104 is incorporated in the image forming apparatus main body 101 and the photosensitive drum 10
2 and the developing roller 117 are, for example, 0.10 m
If the distance is shifted by m, the image density changes by about 0.15. As a result, the photosensitive drum 102 and the developing roller 1
When the distance between the recording paper P and the recording paper P is large, the flying performance of the toner G1 is deteriorated and the development efficiency is deteriorated. is there.

Next, the relationship between the flying property of the toner G1 and the image density will be specifically described with reference to FIG. FIG.
Shows the relationship between the voltage difference between the photosensitive drum 102 and the developing roller 117 and the image density on the photosensitive drum 102. The horizontal axis of the graph shows the voltage difference, and the vertical axis of the graph shows the image density. Is shown. According to this graph, the image density increases when the voltage difference between the photosensitive drum 102 and the developing roller 117 increases, regardless of whether the flying property of the toner G1 is good or bad. It can be seen that the image density on the photosensitive drum 102 is higher when the flying property of G1 is better than when it is poorer.

The flying property of the toner G1 is as follows.
1 and the amount of toner G1 adhering to the developing roller 117 (hereinafter referred to as the amount of adhesion). In the case of this embodiment, the toner G1 used is made of a negatively chargeable polyester resin toner, and its charge amount varies, but the charge amount per unit weight of the toner G1 (hereinafter referred to as charge amount). The larger the value of (), the more difficult it is to develop. This is because, when a large amount of the toner G1 having a large amount of charge is present on the developing roller 117, the image force of the toner G1 becomes large, so that the toner G1 becomes difficult to move from the developing roller 117 to the photosensitive drum 102 side, and the flying property is poor. Because it becomes. When the amount of the toner G1 adhered to the developing roller 117 increases, the charge amount of the toner G1 decreases (see FIGS. 4 and 5).

FIG. 4 shows the toner G1 on the developing roller 117.
And the change in speed of the supply roller 119 with respect to the developing roller 117. The vertical axis of the graph represents the amount of toner G1 adhered, and the horizontal axis of the graph represents the supply roller 11.
9 is a graph showing the speed ratio of the rotation speed of the developing roller 117 to the rotation speed of the developing roller 9 (hereinafter also referred to as the speed ratio of the developing roller 117). According to this graph, when the speed ratio of the developing roller 117 to the toner increases, the amount of toner G1 adhered generally increases. If the horizontal axis of the graph is 1, the supply roller 1
19 indicates that the rotation speed of the developing roller 117 is the same as the rotation speed of the developing roller 117. FIG. 5 shows the developing roller 1
17 shows the relationship between the amount of toner G1 deposited on the roller 17 and the speed ratio of the supply roller 119 to the developing roller 117. The vertical axis of the graph indicates the charge amount of the toner G1, and the horizontal axis of the graph indicates the supply roller 119. 5 is a graph showing the speed ratio of the developing roller 117 to the developing roller 117. According to this graph, the supply roller 11
When the speed ratio of the developing roller 117 to No. 9 increases, the charge amount of the toner G1 generally decreases.

As a result, when the rotation speed of the supply roller 119 with respect to the developing roller 117 is increased, the amount of toner G1 adhered to the developing roller 117 is increased, and the toner G
1 is reduced, and the developing roller 117 of the toner G1 is
The flying performance to the photoreceptor drum 102 is improved. By controlling the rotation speed of the supply roller 119 with respect to the developing roller 117 in this manner, the charge amount and the adhesion amount of the toner G1, which affect the flying property of the toner G1, can be controlled. As a result, the developing device 104 removes the toner G1. It is possible to control the toner concentration when the toner is attached to the photosensitive drum 102. Therefore, in the initialized state of the image forming apparatus, after a solid image (an image in a state where the toner G1 adheres to the entire surface) is formed on the photosensitive drum 102, the density sensor 130 outputs an output result to the controller 140, and If the density data does not reach the predetermined reference value, the controller 140 increases the speed ratio of the supply roller 119 to the development roller 117 with reference to FIGS.
And the amount of toner G1 attached to the photosensitive drum 102 is increased.

On the other hand, based on the output result of the density sensor 130, if the density data reaches a predetermined value or more, the controller 140, for example, with reference to FIGS. By reducing the speed ratio, the supply amount of the toner G1 to the developing roller 117 by the supply roller 119 is reduced, and the photosensitive drum 10
2, the amount of toner G1 attached to the toner 2 is reduced. As described above, the controller 140 determines the relationship between the output result of the density sensor 130 and the speed of the supply roller 119 (that is, the development efficiency).
Is detected, and the controller 140 controls the rotation speed (supply condition) of the supply roller 119 with respect to the development roller 117 so that an appropriate development result is obtained.
Even if the variation in the distance between 02 and the developing roller 117 is greater than expected, the supply amount of the toner G1 can be stabilized. As a result, a good image can be obtained without a decrease in density or the like appearing on the image formed on the recording paper P. The controller 140 stores density information that can be compared with the output result of the density sensor 130 and the correspondence between the density information and the speed ratio information of the supply roller 119 to the developing roller 117. The speed ratio of the supply roller 119 to the developing roller 117 is set so that the output result of 130 becomes a predetermined value.

Next, the operation of the image forming apparatus and the developing apparatus having the above-described configurations will be described. First, the initialization state is controlled as described above. That is, when the photosensitive drum 102 rotates in the direction A in the figure, the surface of the photosensitive drum 102 is charged to a predetermined potential when passing through the charger 103. Thereafter, when the charged portion of the photosensitive drum 102 reaches an exposure position (a position facing the laser exposure device 107) with the rotation of the photosensitive drum 102, the image information is formed to form a solid image thereon. Is irradiated with the laser beam 115 according to the above, an electrostatic latent image is formed.

Next, the toner G1 in the hopper 116 is agitated by the rotation of the stirring blade 120 in the direction B in the drawing and is pushed out toward the supply roller 119, and the supply roller 119 rotates in the direction D in the drawing. As a result, the toner G1 is supplied to the developing roller 117 side. The developing roller 11
The toner G1 attached to the outer peripheral surface of the developing roller 117 is conveyed to the regulating blade 118 side while being carried on the developing roller 117 rotating at a predetermined speed in the direction of arrow C.
To form a thin layer.

The toner G1 thus uniformly carried on the developing roller 117 in the form of a thin layer is conveyed to the photosensitive drum 102 side. In this case, in the developing area, the toner G1 is turned into a powder cloud by the action of the electric field generated by the bias control of the power supply device 114, and the developing roller 1
17, it flies from the outer peripheral surface and adheres to the electrostatic latent image formed on the photosensitive drum 102, and the electrostatic latent image is visualized.
After that, the density sensor 130 outputs the output result to the controller 140, so the controller 140 controls the speed ratio of the supply roller 119 to the developing roller 117 so that the above-described density data reaches a predetermined value. Thereafter, the photosensitive drum 102 rotates while carrying an image formed by the toner G1 on its surface, and the toner G1 is
Is scraped off by the blade 106a. After performing the control of the initialization state, the photosensitive drum 102 is charged by the charger 103 while rotating in the direction A in the drawing, and the charged portion of the photosensitive drum 102 is irradiated with the laser light 115 according to the image information. The toner G1 flies from the outer peripheral surface of the developing roller 117 and adheres to the electrostatic latent image formed on the photosensitive drum 102, and the electrostatic latent image is formed. Are visualized.

The image formed by the toner G1 is transferred to the transfer unit 10
5, the transfer device 10
5, a transfer electric field is applied, whereby the toner image is sucked and transferred to the recording paper P side. Then, the recording paper P to which the image has been transferred by the toner G1 is
After being separated from the sheet 2, the sheet is sent to the fixing device 111 along the sheet guide 110 c and further discharged to the sheet discharge stack 112. On the other hand, the transfer device 105
, A small amount of toner G1 remains where the toner image was present (toner image trace). When the residual toner G1 reaches the cleaner 106, it is scraped and removed by the blade 106a.

As described above in detail, according to the present embodiment, the toner G1
In the developing device 104 having a developing roller 117 for supplying the toner G1 to the developing roller 117 and supplying the toner G1 to the developing roller 117.
A density sensor 130 for detecting the above development result is provided, and a controller 140 for changing the rotation speed of the supply roller 119 with respect to the development roller 117 based on the output result of the density sensor 130 is provided.
The supply amount of the toner G1 to the toner 17 is stabilized, and a good image is formed on the recording paper P.

Next, a second embodiment will be described with reference to FIGS. FIG. 6 illustrates the developing roller 117.
The graph shows the relationship between the amount of toner G1 attached and the diameter of the supply roller 119, with the vertical axis of the graph showing the amount of toner G1 attached and the horizontal axis of the graph showing the diameter of the supply roller 119. . According to this graph, it can be seen that as the diameter of the supply roller 119 increases, the amount of toner G1 attached increases. FIG. 7 shows the toner G on the developing roller 117.
The graph shows the relationship between the banding amount of No. 1 and the diameter of the supply roller 119. The graph shows the charge amount of the toner G1 on the vertical axis of the graph, and the diameter of the supply roller 119 on the horizontal axis of the graph.
According to this graph, it is understood that as the diameter of the supply roller 119 increases, the charge amount of the toner G1 increases.
The diameter of the supply roller 119 may be changed using a member such as a cam.

Thus, in the case of this embodiment, the controller 140 determines the relationship between the output result of the density sensor 130 and the diameter of the supply roller 119 (that is, the development efficiency).
6 and 7 so as to obtain an appropriate development result.
By controlling the size of the diameter of the supply roller 119 while referring to, the charge amount and the adhesion amount of the toner G1 which affects the flying property of the toner G1 can be controlled. As a result,
As in the first embodiment, an appropriate amount of toner G1 adheres to the photosensitive drum 102. Thus, the controller 140
Changes the diameter of the supply roller 119 based on the output result of the density sensor 130 to stabilize the supply amount of the toner G1. Thus, a good image is formed on the recording paper P.

Next, a third embodiment will be described with reference to FIGS. FIG. 8 shows the developing roller 117.
The graph shows the relationship between the amount of toner G1 attached and the bias voltage applied to the regulating blade 118. The graph shows the amount of toner G1 attached on the vertical axis of the graph and the regulating blade bias voltage on the horizontal axis of the graph. Show. According to this graph,
When the bias voltage to the regulating blade 118 increases,
It can be seen that the amount of toner G1 attached increases. FIG. 9 shows the relationship between the amount of toner G1 applied on the developing roller 117 and the bias voltage to the regulating blade 118. The vertical axis of the graph indicates the charge amount of the toner G1, and the horizontal axis of the graph indicates the charge amount. Fig. 3 shows a graph of the regulation blade bias voltage.
According to this graph, when the bias voltage to the regulating blade 118 increases, the charge amount of the toner G1 increases.

Accordingly, in the case of this embodiment, the controller 140 detects the relationship between the output result of the density sensor 130 and the bias voltage to the regulating blade 118 (that is, the development efficiency), and obtains an appropriate development result. 8 and 9, by controlling the bias voltage to the regulating blade 118, it is possible to control the amount of charge and the amount of adhesion of the toner G1 which affects the flying property of the toner G1, and as a result, As in the first embodiment, an appropriate amount of toner G
1 adheres to the photosensitive drum 102. As described above, the controller 140 controls the bias voltage (applied voltage) to the regulating blade 118 based on the output result of the density sensor 130.
Is changed to stabilize the supply amount of the toner G1.
A good image is formed on the recording paper P.

Next, a fourth embodiment will be described with reference to FIG.
This will be described with reference to FIGS. FIG. 10 shows the developing roller 1
FIG. 7 is a schematic diagram showing a positional relationship between the control blade 17 and a regulating blade 118 and the like. FIG. 11 shows the amount of toner G1 deposited on the developing roller 117 and the height L1 of the entrance to the regulating blade 118.
10 (see FIG. 10), the vertical axis of the graph shows the amount of toner G1 attached, and the horizontal axis of the graph shows the height L1 of the entrance to the regulating blade 118. According to this graph, it can be seen that as the height L1 of the entrance to the regulating blade 118 increases, the amount of toner G1 attached increases. FIG. 12 shows the relationship between the amount of toner G1 attached to the developing roller 117 and the height L1 of the entrance to the regulating blade 118. The vertical axis of the graph represents the amount of charge of the toner G1. Regulation blade 118 on the horizontal axis
3 shows a graph of the height L1 of the entrance to the entrance. According to this graph, the height L1 of the entrance to the regulating blade 118
It can be understood that the charge amount of the toner G1 decreases as the value of .gamma. Increases.

Accordingly, in the case of this embodiment, the controller 140 detects the relationship between the output result of the density sensor 130 and the height L1 of the entrance to the regulating blade 118 (that is, the development efficiency), and determines the appropriate development result. By controlling the height L1 of the entrance to the regulating blade 118 while referring to FIG. 11 and FIG.
The amount of charge and the amount of adhesion of the toner G1, which affects the flight performance of the toner, can be controlled, and as a result, an appropriate amount of the toner G1 adheres to the photosensitive drum 102 as in the first embodiment. As described above, the controller 140 changes the height L1 (the position of the supply unit) of the entrance to the regulating blade 118 with respect to the supply roller 119 based on the output result of the density sensor 130, and stabilizes the supply amount of the toner G1. Therefore, a good image is formed on the recording paper P.

Next, a fifth embodiment will be described with reference to FIG.
This will be described with reference to FIGS. FIG. 15 shows the developing roller 1
FIG. 7 is a schematic view showing a positional relationship between the control blade 17 and the control blade 118 and the like. When the cam K1 rotates and the notched portion K1a contacts the control blade 118, the control blade 118 presses the developing roller 117 with a small pressure. On the other hand, when the large diameter portion K1b comes into contact with the regulating blade 118, the regulating blade 118
Press 7.

FIG. 13 shows the relationship between the adhesion amount of the toner G1 on the developing roller 117 and the pressure at which the regulating blade 118 presses the developing roller 117. The vertical axis of the graph indicates the adhesion of the toner G1. The amount is shown on a graph with the pressure taken on the horizontal axis of the graph. According to this graph, it can be seen that as the pressure at which the regulating blade 118 presses the developing roller 117 increases, the amount of toner G1 attached decreases. FIG. 14 shows the relationship between the amount of the toner G1 attached to the developing roller 117 and the pressure with which the regulating blade 118 presses the developing roller 117. The axis of the graph shows the pressure. According to this graph, it can be seen that when the pressure at which the regulating blade 118 presses the developing roller 117 increases, the charge amount of the toner G1 increases.

Thus, in the case of this embodiment, the controller 140 detects the relationship between the output result of the density sensor 130 and the pressure at which the regulating blade 118 presses the developing roller 117 (ie, the developing efficiency), and By controlling the pressure by the regulating blade 118 while referring to FIG. 13 and FIG. 14 so as to obtain the development result, the charge amount and the adhesion amount of the toner G1, which influence the flying property of the toner G1, can be controlled. As in the first embodiment, an appropriate amount of toner G1 adheres to the photosensitive drum 102.
Therefore, based on the output result of the density sensor 130, the controller 140 controls the developing roller 117 and the regulating blade 1
Since the supply pressure of the toner G1 is stabilized by changing the contact pressure with the toner image 18, the image formed on the recording paper P is excellent. However, the developing roller 117 and the regulating blade 118
You may change the contact width with.

It should be noted that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the spirit of the present invention. For example, without using the density sensor 130 for detecting the density of the toner G1 on the photosensitive drum 102, the photosensitive drum 10
The factors affecting the development result may be detected by measuring the distance between the developing roller 117 and the developing roller 117, or measuring the capacitance between the photosensitive drum 102 and the developing roller 117. In this case, any device that detects the development efficiency may be used.

The controller 140 may control the combination of the above-described embodiments as appropriate. For example, in addition to controlling the rotation speed and the diameter of the supply roller 119 in combination, the controller blade 116 for the developing roller 117 may be controlled.
, The contact pressure, the contact width, the applied voltage and the like may be controlled in combination. Since the flying performance of the toner G1 is also affected by the durability period of the developing device 104, the controller 140 (survival detecting means) detects the remaining life of the developing device 104 by detecting the remaining life of the recording paper P on which the image is formed. The number of sheets is counted, the remaining life of the developing device 104 is detected, and based on the detected value, the controller 140
The supply conditions by the control blade 19 and the regulating blade 118 may be changed.

Further, since the flying property of the toner G1 is also affected by the environment such as humidity and temperature, in order to detect environmental conditions in the developing device 104, for example, a hygrometer and a thermometer for detecting humidity and temperature and the like are used. (Environment detecting means) may be provided, and the controller 140 may change the supply condition by the supply roller 119 and the regulating blade 118 based on the output result. It goes without saying that this image forming apparatus may be applied to a full-color copying machine, a facsimile machine, or the like.

[0047]

As described above, according to the developing apparatus of the present invention, the change in the separation distance between the developer carrier and the image carrier, the environmental change, and the change in the development state at the end of the endurance period. Even if it occurs, a good image can be obtained. Further, according to the image forming apparatus of the present invention, since the developing device of the present invention is used, a good image is always formed without the image formed on the recording paper being suddenly deteriorated.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a main part of an image forming apparatus according to a first embodiment.

FIG. 2 is a diagram illustrating a graph of a relationship between an image density of toner adhered to a photosensitive drum and an area ratio when a distance between the photosensitive drum and a developing roller changes in the first embodiment. is there.

FIG. 3 is a diagram showing a graph of a relationship between a voltage difference between a photosensitive drum and a developing roller and an image density in the first embodiment.

FIG. 4 is a graph showing a relationship between a speed ratio of a supply roller to a developing roller and a toner adhesion amount in the first embodiment.

FIG. 5 is a diagram illustrating a graph of a relationship between a speed ratio of a supply roller to a development roller and a toner charge amount in the first embodiment.

FIG. 6 is a diagram illustrating a graph of a relationship between a diameter of a supply roller and a toner adhesion amount in the second embodiment.

FIG. 7 is a graph showing a relationship between a diameter of a supply roller and a toner charge amount in the second embodiment.

FIG. 8 is a diagram illustrating a graph of a relationship between a bias of a regulating blade and a toner adhesion amount according to a third embodiment.

FIG. 9 is a diagram illustrating a graph of a relationship between a bias of a regulating blade and a toner charge amount according to a third embodiment.

FIG. 10 is a schematic diagram illustrating a positional relationship between a developing roller and a regulating blade according to a fourth embodiment.

FIG. 11 is a diagram illustrating a graph of a relationship between an entrance height of a regulating blade and a toner adhesion amount according to a fourth embodiment.

FIG. 12 is a diagram illustrating a graph of a relationship between an entrance height of a regulating blade and a toner charge amount according to a fourth embodiment.

FIG. 13 is a diagram illustrating a graph of a relationship between a contact pressure of a regulating blade and a toner adhesion amount according to a fifth embodiment.

FIG. 14 is a diagram illustrating a graph of a relationship between a contact pressure of a regulating blade and a toner charge amount according to a fifth embodiment.

FIG. 15 is a schematic diagram illustrating a positional relationship between a developing roller and a regulating blade according to a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Image forming apparatus main body 102 Photoconductor drum 103 Charger 104 Developing device 107 Laser exposure device 114 Power supply device 116 Toner hopper 117 Developing roller 118 Regulator blade 119 Supply roller 120 Stirring blade 130 Density sensor 140 Controller

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA10 DA14 EA04 EA05 2H077 AB03 AB15 AC04 AC13 AD02 AD06 AD13 AD17 AD31 AD35 AE02 CA08 DA03 DA18 DA24 DA47 DB08 DB25 EA14 EA16 EA20 FA25 GA02 GA03 GA13

Claims (9)

[Claims] 1. A developing device comprising: a developer carrier that supplies a developer to an image carrier to perform a developing operation; and a supply unit that supplies the developer to the developer carrier. A developing device comprising: a detection unit; and a control unit that changes a supply condition of the supply unit based on a detection result of the detection unit. 2. The developing device according to claim 1, wherein the supply conditions of the supply unit include: a rotation speed of the supply unit;
The developing device may be at least one of a position of the supply unit, an applied voltage of the supply unit, a diameter of the supply unit, a contact pressure and a contact width of the supply unit. 3. The developing device according to claim 1, wherein the supply unit includes a supply roller, and the control unit controls a rotation speed of the supply roller. 4. The developing device according to claim 1, wherein said supply means includes a supply roller, and said control means controls a diameter of said supply roller. 5. The developing device according to claim 1, wherein the supply unit includes a supply roller and a regulating blade facing the supply roller, and the control unit controls a positional relationship between the supply roller and the regulation blade. A developing device. 6. The developing device according to claim 1, wherein the supply unit includes a supply roller and a regulating blade that contacts the supply roller, and the control unit determines a contact pressure or a contact width between the supply roller and the regulation blade. A developing device characterized by controlling. 7. The developing device according to claim 1, wherein the supply unit includes a supply roller and a regulating blade facing the supply roller, and the control unit controls an applied voltage between the supply roller and the regulation blade. A developing device. 8. The developing device according to claim 1, wherein the detection unit includes a developer concentration on the image carrier, an amount of the developer attached on the developer carrier, and the image carrier and the developer. A developing device for detecting at least one of a distance from a carrier, an environmental state in the developing device, and a remaining life of the developing device. 9. Any one of claims 1 to 8
An image forming apparatus comprising: a developing device described above, an image carrier for carrying an image, and image forming means for forming an image on the image carrier.