JP3224617B2 - Developing device and image forming device - Google Patents

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 in an image forming apparatus such as a copying machine, a facsimile, a printer, etc., and more particularly to a developing device using a developer regulated to a predetermined thickness by a developer regulating member. And a developing device for developing the latent image formed on the surface of the latent image carrier.

[0002]

2. Description of the Related Art Conventionally, for example, a developer formed by mixing and stirring a toner and a carrier is carried on the surface of the developer carrying member by magnetic force generated by a magnetic field generating means provided inside the developer carrying member. 2. Description of the Related Art There has been known a developing device in which a developer on a body surface is formed into a thin layer having a predetermined thickness by a developer regulating member, and then supplied to the surface of a latent image carrier to develop a latent image. Further, as a developing device having a developer regulating member as described above, for example, Japanese Patent Application Laid-Open No. 63-61275 discloses a developing device in which an end of a developer regulating member is opposed to a developer carrier.
A developer circulation limiting member having a developer guide surface for gradually reducing the gap between the developer carrier and the developer carrier from the rotation direction upstream side of the developer carrier, and a developer guide surface of the developer circulation limitation member having a maximum magnetic field generating portion. A developing device having a magnetic field generating means facing the developer, forming a thin developer layer on the surface of the developer carrier stably for a long time, and preventing the developer from scattering. .

[0003]

However, in a developing device having a developer regulating member as described above, for example, as shown in FIGS. 8A and 8B, a side of a doctor 100 as a developer regulating member is used. The developer wraps around from the end, and surplus agent 102 is applied to the end of the developing sleeve 101 as a developer carrier.
However, there is a problem that the problem may occur.

When surplus agent is generated at the end of the developing sleeve 101, the developer binding force by the magnetic field generating means is relatively weak at the end of the developing sleeve 101 as compared with the central portion. The surplus agent 102 may be scattered out of the developing device 103 by the centrifugal force due to the rotation of the sleeve 101. When the developer is scattered, the amount of the developer is reduced to cause poor pumping, and also causes many troubles such as leaks to the copying machine main body. According to the experiment of the present inventor, as shown in FIG. 10, when the surplus agent 102 is present at the end of the developing sleeve 101, it is recognized that about 3 g is scattered in 3 minutes.
On the other hand, when the surplus agent 102 was not present at the end of the developing sleeve 101, no scattering of the developer outside the developing device 103 was observed.

In a conventional developing device, as shown in FIG. 11A, a side seal 104 is provided at the end of the normal developing sleeve 101 to prevent toner scattering. Here, as shown in FIG. 11B, when the surplus agent 102 gets under the side seal 104, a wedge-shaped agent pool is generated at the time of normal rotation of the developing sleeve 101, and this agent pool is used as a latent image carrier. It comes into contact with the photosensitive drum 105. As a result, the rotation speed of the photosensitive drum 105 fluctuates, and a displacement occurs at the time of forming a latent image or transferring a toner image. Further, for example, in a full-color copying machine, an operation of eliminating the ears of the developer formed on the developing sleeve 101 by reversing the developing sleeve 101 (referred to as an ear cutting operation). At this time, the shape of the surplus agent 102 under the side seal 104 changes, or the developing device slightly upstream from the region 106 where the developer passing through the developing region and remaining on the developing sleeve 101 is dropped into the developing device 103 once. The developer accumulated at the point 107 in the inside may penetrate under the side seal 104 to increase the amount of the developer under the side seal 104. For this reason, the fluctuation rate of the rotation speed of the photosensitive drum 105 may become larger than that at the time of normal rotation of the developing sleeve 101 as shown in FIG. When the amount of the surplus agent 102 under the side seal 104 increases, the surplus agent 102
The rotation of the developing sleeve 101 may be stopped (locked) due to the lifting and turning up of the developing sleeve 101. According to an experiment conducted by the inventor, as shown in FIG. 12B, when there is no surplus agent 102 at the end of the developing sleeve 101, the photosensitive drum 105 is rotated in both forward and reverse rotations of the developing sleeve 101. There was no large change in the rotation speed, and no positional displacement that caused a problem on the image occurred.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a developing apparatus and a developing apparatus which prevent the generation of a surplus agent at an end of a developer carrier.
An object of the present invention is to provide an image forming apparatus including:

[0007]

To achieve the above Symbol purpose SUMMARY OF THE INVENTION The invention of Claim 1 includes a developer carrying member for supplying the developer to the latent image bearing member a latent image is formed on the surface, A first developer regulating member disposed opposite to the developer carrier to regulate the developer on the surface of the developer carrier to a predetermined thickness; and a desired magnetic force applied to the surface of the developer carrier. And a magnetic field generating means for generating a magnetic field of the developer carrier upstream of the first developer regulating member in the developer carrying direction of the developer carrier and at both ends in the axial direction of the developer carrier. It disposed a second developer regulating member for regulating the amount of the developer, the second current
The magnetic force on the surface of the developer carrying member facing the image material regulating member
It is characterized by being set to 50 gauss or less . According to a second aspect of the present invention, there is provided a latent image carrier,
Latent image forming means for forming a latent image on a carrier, and the latent image forming means
The developer is supplied to the latent image carrier on which the latent image is formed
An image forming apparatus having a developing device for forming an image.
A developing device according to claim 1 is used as an image device .

[0008]

According to the first or second aspect of the present invention, the second developer regulating member is provided on the upstream side of the developer carrying member in the developer carrying direction and at both ends in the axial direction of the developer carrying member.
The developer conveyed by the developer carrier is only a predetermined amount of the developer at both ends in the axial direction of the developer carrier is conveyed by the second developer regulating member. After being dropped, the first developer regulating member scrapes off a predetermined amount over the entire width of the developer carrying member in the axial direction, and is used for development. Further , since the magnetic force on the surface of the developer carrier facing the second developer regulating member is set to 50 Gauss or less, the amount of the regulated developer is regulated stably without destabilizing the amount of developer. be able to.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an example of a color copying apparatus which is an image forming apparatus to which the present invention can be applied will be described. FIG. 1 is a schematic configuration diagram of a color copying apparatus, and FIG. 2 is an enlarged view around a photoconductor and an intermediate transfer belt. A color image reading device (hereinafter, referred to as a color scanner) 1 forms an image of an original 3 on a color sensor 7 via an illumination lamp 4, a mirror group 5, and a lens 6, and outputs color image information of the original, for example. Blue (B), Green (Gree)
n, hereinafter referred to as G) and red (Red, hereinafter referred to as R) color-separated lights, and converted into electrical image signals.
Then, based on the B, G, and R color separation image signal intensity levels obtained by the color scanner 1, color conversion processing is performed by an image processing unit (not shown), and black (hereinafter, Bk
, Cyan (Cyan), magenta (Magenta), and yellow (Yellow) color image data is obtained. This is visualized by Bk, C, M, and Y by a color image recording device (hereinafter, referred to as a color printer) 2 described below, and the resulting toner images are superimposed to form a four-color full-color image. Form.

The writing optical unit 8 of the color printer 2 converts the color image data from the color scanner 1 into an optical signal, performs optical writing corresponding to the original image, and forms an electrostatic latent image on the photosensitive drum 9. I do. The photoreceptor drum 9 rotates counterclockwise as indicated by an arrow, and around the photoreceptor drum, a photoreceptor cleaning unit (including a pre-cleaning static eliminator) 10, a static elimination lamp 11, a charger 12, a potential sensor 13, a Bk developing device 14, a C developing device 15, an M developing device 16, a Y developing device 17, an optical sensor 18 for detecting a development density pattern, an intermediate transfer belt 19, and the like are arranged.

Each developing device is provided with a developing sleeve (14a, 15a, 16a, 17a) which rotates by bringing an ear of developer into contact with the surface of the photoreceptor 9 to develop an electrostatic latent image, and draws up the developer. A developing paddle (14) that rotates to stir
b, 15b, 16b, 17b) and a toner concentration sensor for the developer (14c, 15c, 16c, 17c).

Hereinafter, the outline of the copy operation will be described with an example in which the order of the developing operation (color image forming order) is Bk, C, M, and Y (however, the image forming order is not limited to this). . When the copying operation is started, reading of the Bk image data is started at a predetermined timing by the color scanner 1, and light writing by a laser beam and formation of a latent image are started based on this image data (hereinafter, electrostatic image formation by the Bk image data). The latent images are referred to as Bk latent images, and C, M, and Y are referred to as C latent images, M latent images, and Y latent images, respectively). This B
Before the leading end of the latent image reaches the developing position of the Bk developing device 14 so that development can be performed from the leading end of the k latent image, the developing sleeve 1
4a is started, and the Bk latent image is developed with Bk toner. Thereafter, the developing operation of the Bk latent image area is continued, and when the rear end of the latent image has passed the Bk developing position, the developing operation is disabled. This is completed at least before the leading end of the C latent image based on the next C image data arrives.

The Bk toner image formed on the photoreceptor 9 is transferred onto the surface of an intermediate transfer belt 19 which is driven at the same speed as the photoreceptor (hereinafter, transfer of the toner image from the photoreceptor to the intermediate transfer belt is referred to as belt transfer). ). The belt transfer is performed by applying a predetermined bias voltage to the transfer bias rollers 20a and 20b while the photoconductor 9 and the intermediate transfer belt 19 are in contact with each other. The intermediate transfer belt 19 includes a photosensitive member 9.
The toner images of Bk, C, M, and Y which are sequentially formed are sequentially aligned on the same surface to form a four-color superimposed belt transfer image, and thereafter, collective transfer is performed on transfer paper. This intermediate transfer belt unit will be described later.

On the photoreceptor 9 side, the process proceeds to the step C after the step Bk. At a predetermined timing, the reading of the C image data by the color scanner 1 starts, and the formation of the C latent image is performed by laser beam writing based on the image data. C developing device 1
5 starts the rotation of the developing sleeve 15a with respect to the developing position after the trailing edge of the preceding Bk latent image has passed and before the leading end of the C latent image has arrived. develop. Thereafter, the development of the C latent image area is continued, and when the trailing end of the latent image has passed, the development is disabled as in the case of the Bk developing device. This is also completed before the leading end of the next M latent image arrives. In addition, about each process of M and Y,
The operations of reading image data, forming a latent image, and developing are performed in the same manner as in the above-described steps Bk and C.

Next, the intermediate transfer belt unit will be described. The intermediate transfer belt 19 is stretched around a drive roller 21, transfer bias rollers 20a and 20b, and a driven roller group, and is driven and controlled by a drive motor (not shown) as described later. Belt cleaning unit 22
Is composed of a brush roller 22a, a rubber blade 22b, a mechanism 22c for contacting and separating from a belt, and the like. After the first color Bk image is transferred to the belt, the second, third, and fourth colors are transferred to the belt. Is separated from the belt surface by the contact / separation mechanism 22c.

The paper transfer unit 23 includes a paper transfer bias roller 23a, a roller cleaning blade 23b,
And a mechanism 23c for contacting and separating from the belt. The bias roller 23a is normally separated from the surface of the belt 19, but it is timed when the superimposed images of four colors formed on the surface of the intermediate transfer belt 19 are collectively transferred to transfer paper, and the contact / separation mechanism 23c is set. The roller 2
A predetermined bias voltage is applied to 3a to perform transfer to paper. The transfer paper 24 is fed by the feed roller 25 and the registration roller 26 at the timing when the leading end of the four-color superimposed image on the intermediate transfer belt surface reaches the paper transfer position.

Here, the drive control of the intermediate transfer belt 19 will be described. As a method of driving the intermediate transfer belt 19, the following three methods can be considered as an operation method after the belt transfer of the Bk toner image of the first color is completed to the end, and one of these methods or one of the copy speeds is considered. Efficiently combine multiple of these methods according to the copy size from the side,
The intermediate transfer belt 19 is driven. (1) First, a constant speed forward system will be described as a first system. After the belt transfer of the Bk toner image, the forward movement is continued at a constant speed. When the front end position of the Bk image on the surface of the belt 19 reaches the belt transfer position at the contact portion with the photoconductor 9 again, the front end of the next C toner image on the photoconductor 9 side is exactly at that position. The image is formed at a proper timing. As a result, the C image is belt-transferred on the intermediate transfer belt 19 while being accurately aligned with the Bk image. After that, by the same operation, the process proceeds to the M and Y image processes.
A four-color superimposed belt transfer image is obtained. The four-color superimposed toner image on the belt surface is collectively transferred to the transfer paper 24 as described above while moving forward as it is after the fourth color Y toner image belt transfer step. (2) Next, a skip forward method will be described as a second method. When the transfer of the Bk toner image to the belt is completed, the belt 19 is separated from the surface of the photoreceptor 9, skipped at a high speed in the forward direction, and returned to the original forward speed after moving a predetermined amount. Thereafter, the belt 19 is brought into contact with the photoconductor 9 again. When the front end position of the Bk image on the surface of the belt 19 reaches the belt transfer position again, an image is formed on the photoconductor 9 side at a timing such that the front end portion of the next C toner image is exactly at that position. I have. As a result, the image of C is transferred to the Bk image with the belt accurately aligned with the Bk image. Thereafter, the process proceeds to the M and Y image processes by the same operation.
A color transfer belt transfer image is obtained. The four-color superimposed toner image on the surface of the belt 19 is collectively transferred to the transfer paper 24 in the same forward movement degree as the Y-color-increased belt transfer process for the fourth color. (3) Next, a reciprocating (quick return) method will be described as a third method. When the transfer of the Bk toner image to the belt is completed, the belt 19 is separated from the surface of the photoconductor 9, and the forward movement is stopped, and at the same time, the belt 19 is returned at a high speed in the reverse direction. In the return, the front end position of the Bk image on the surface of the belt 19 passes through a position corresponding to the belt transfer in the reverse direction, and after moving a predetermined distance, stops and enters a standby state. Next, when the leading end of the C toner image on the photoconductor 9 reaches a predetermined position before the belt transfer position, the intermediate transfer belt 19 is started again in the forward movement direction. Also belt 1
9 is brought into contact with the surface of the photoconductor 9 again. Also in this case, the belt transfer is performed under the condition that the C image is accurately overlapped with the Bk image on the belt 19 surface. Thereafter, the same operation is performed to proceed to the Y and M image processes.
A color transfer belt transfer image is obtained. Following the belt transfer process for the fourth color Y toner image,
The belt moves forward at the same speed without returning, and the belt 19
The four-color superimposed toner image on the surface is collectively transferred to the transfer paper 24.

As described above, the transfer paper 24 on which the four-color superimposed toner image has been transferred from the intermediate transfer belt surface is conveyed to the fixing device 28 by the paper conveying unit 27, and the fixing roller is controlled to a predetermined temperature. 28a and pressure roller 28
In step b, the toner image is melted and fixed, carried out to the copy tray 29, and a full-color copy is obtained.

The photoreceptor 9 after the belt transfer is replaced with a photoreceptor cleaning unit 10 (a pre-cleaning static eliminator 10).
a, the brush roller 10b, and the rubber blade 10c) are used to clean the surface, and the charge is uniformly removed by the charge removing lamp 11. After the transfer of the toner image onto the transfer paper 24, the surface of the intermediate transfer belt 19 is cleaned by pressing the cleaning unit 22 again by the contact / separation mechanism 22c.

At the time of repeat copy, the color scanner 1
The operation of (1) and image formation on the photoconductor 9 proceed to the second sheet Bk (first color) image step at a predetermined timing following the first sheet Y (fourth color) image step. In the intermediate transfer belt 19, the second Bk toner image is applied to the area where the surface is cleaned by the cleaning unit 22, following the batch transfer process of the first four-color superimposed image onto the transfer paper. The belt is transferred. After that, the operation is the same as that of the first sheet. The transfer paper cassettes 30, 31, 32,
Reference numeral 33 stores transfer papers of various sizes, which are fed and conveyed in the direction of the registration rollers 26 from the storage cassette of the size paper designated by the operation panel (not shown) at a certain timing. Reference numeral 34 denotes a manual paper feed tray for OHP paper and thick paper.

The above is the description of the copy mode for obtaining four full colors. In the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. Will be. Further, in the case of the single-color copy mode, only the developing device of the color is set in the developing operation (spring) until the predetermined number of sheets is completed, and the intermediate transfer belt 19 is kept in contact with the surface of the photoconductor 9. In the forward movement direction, the belt is driven at a constant speed.
The copying operation is performed with the touch panel 9 kept in contact.

Next, referring to FIG. 3, each developing device (14, 1
5, 16, 17) will be described. Since the configuration of the main part in each of the developing units (14, 15, 16, 17) is the same, the developing sleeve 14a of the Bk developing unit 14 will be described below as an example.

The developing device 14 includes the developing sleeve 14a, the developing paddle 14b, and the toner density sensor 14 as described above.
c, and a doctor 14d as a developer regulating member for making the developer on the surface of the developing sleeve 14a a thin layer of a predetermined thickness is disposed opposite to the developing sleeve 14a.

The developing sleeve 14a includes a hollow cylindrical member 14a 'rotatably configured and a hollow cylindrical member 14a'.
and a magnet (not shown) as a magnetic field generating means fixedly disposed inside a ′ so that the developer is carried and carried on the surface of the hollow cylindrical member 14a ′ by the magnetic force of the magnet. Has become. The developing sleeve 1 in FIG.
The solid line around 4a indicates the magnetic force in the normal direction on the peripheral surface of the sleeve 14a, and the broken line indicates the tangential magnetic force on the peripheral surface of the sleeve 14a. Here, a plurality of normal magnetic poles P1 to P6 are formed on the surface of the hollow cylindrical member 14a 'by magnets. In the figure, the magnetic pole P1 is
A magnetic pole formed in a developing area opposed to the photoconductor drum 9 and called a main pole, a magnetic pole forming a spike of developer whose tip contacts the surface of the photoconductor drum 9 on the surface of the hollow cylindrical member 14a '; In the developing device 14 of this embodiment, for example, 11
It is set to be 47 Gauss. The magnetic pole P2 is
These are magnetic poles for transporting the developer remaining on the surface of the hollow cylindrical member 14a 'after passing through the developing area into the developing device 14. In the developing device 14 of this embodiment, the magnetic pole is set to, for example, 652 gauss. The magnetic pole P3 is a hollow cylindrical member 14a '.
This is a virtual pole formed at a position where the developer remaining on the surface drops from the surface of the hollow cylindrical member 14a '. The magnetic pole P4 is a magnetic pole that pumps the developer in the developing device 14 to the surface of the hollow cylindrical member 14a ', and is set to, for example, 767 gauss in the developing device 14 of the present embodiment. Magnetic pole P5
Is a magnetic pole for transporting the developer pumped to the surface of the hollow cylindrical member 14a 'to the doctor 14d, and is set to be, for example, 288 gauss in the developing device 14 of the present embodiment. The magnetic pole P6 is a magnetic pole that transports the developer that has passed through the doctor 14d to the main pole.
Is set to 811 gauss, for example.

In such a developing device 14, the developer flows from the side end of the doctor 14d as described above,
Excess agent may be generated at the axial end on the surface of the hollow cylindrical member 14a '(see FIGS. 8A and 8B). Thus, the present inventor examined the relationship between the position of the doctor 14d and the state of generation of the surplus agent. As a result, the development was performed with respect to the virtual vertical surface 41 passing through the center 140 of the developing sleeve 14a as shown in FIG. On the upstream side of the sleeve 14a in the developer conveying direction, it is recognized that the surplus agent is generated or not generated depending on the angle θ formed by the virtual plane 42 passing through the tip of the doctor 14d and the center 140 of the developing sleeve 14a. Was done. According to the experiment of the present inventor, as shown in FIG. 4B, no surplus agent is generated when the angle θ is 25 ° or more, and it is recognized that a surplus agent is generated when the angle θ is less than 25 °. Was. Here, the condition that “the angle θ is less than 25 °” also includes a case where the virtual plane 42 is between the virtual vertical plane 41 and the downstream side in the developer transport direction to the development area. The following are conceivable reasons why the surplus agent is generated or not generated at the angle θ of 25 °. That is, as shown in FIG.
When the angle is 5 ° or more, the developer regulated by the doctor 14 d in the relatively steep region of the developing sleeve 14 a easily returns to the developing device 14 due to gravity, and the developer 14 d
The developer flowing from the end of the developing sleeve 14a is returned to the inside of the developing device 14 by gravity because the magnetic force is weak at the end of the developing sleeve 14a, and it is considered that no surplus agent is generated. On the other hand, when the angle θ is less than 25 ° as shown in FIG. 5B, the developer regulated by the doctor 14 d in the relatively sloping region of the developing sleeve 14 a is hard to return to the inside of the developing device 14 ( Since the inclination is gentle, it is difficult to drop even under the action of gravity). Also, since the developer flowing from the end of the doctor 14d is conveyed to the downstream side by the rotation of the developing sleeve 14a, it is considered that excess developer is generated. Can be

Therefore, in this embodiment, for example, due to restrictions on the device layout, the developing sleeve 14a is arranged in the axial direction of the developing sleeve 14a with respect to the developing device 14 in which the doctor 14d is arranged so that the angle θ is less than 25 °. A mechanism is provided at both ends to prevent the generation of excess agent. As shown in FIG. 6A, a mechanism for preventing the generation of the excess
On the upstream side in the developer transport direction from 4d, a pre-doctor 14e is provided as a second developer regulating member that regulates the amount of developer on the surface of the developing sleeve 14a at both ends of the developing sleeve 14a. In FIG. 6B, the width (T) of the predoctor 14e on the end of the developing sleeve 14a is set to a width that can effectively prevent the generation of the surplus agent. Further, as shown in the drawing, it is desirable to dispose the developing sleeve 14a so as to slightly enter the effective developing area of the developing sleeve 14a. For example, 10 mm from the end of the developing sleeve 14a.
When the pre-doctor 14e is used as an effective development area from the point (t), the pre-doctor
Even when it was extended to 0 mm (T), the generation of the surplus agent could be prevented without causing a problem in the development. However, if the penetration into the effective development area is too large, there is a possibility of causing a problem in the development. Therefore, it is desirable that the width of the pre-doctor 14e on the development sleeve 14a be within 50 mm. The gap between the pre-doctor 14e and the surface of the developing sleeve 14a may be set to be substantially the same as the gap between the doctor 14d and the surface of the developing sleeve 14a, or may be set to be wider or narrower.

Further, when the developer regulating member is provided in a place having a strong magnetic force in the normal direction, the regulated amount of developer is unstable. Therefore, in this embodiment, as shown in FIG. 7, the developing sleeve 14 facing the predoctor 14e is used.
It is desirable that the magnetic force in the normal direction on the peripheral surface a be weakened, for example, set to 50 Gauss or less. In the illustrated example, the magnetic pole P5 (FIG. 3) for transporting the developer to the doctor 14d
Is divided into a magnetic pole P5a on the upstream side in the developer transport direction and a magnetic pole P5b on the downstream side with respect to the pre-doctor 14e.

With the above configuration, the magnetic pole P
6, only a predetermined amount of the developer at both ends in the axial direction of the developing sleeve 14a is scraped off by the pre-doctor 14e, and is transported to the doctor 14d by the magnetic pole P5b, as shown in FIG. You. After that, the developer having a smaller amount at both ends than the central portion in the axial direction of the developing sleeve 14a is scraped off by a predetermined amount over the entire width in the axial direction of the developing sleeve 14a by the doctor 14d and is subjected to development. Therefore, in the present embodiment, the developer regulated by the doctor 14d is regulated in advance by the pre-doctor 14e at both ends in the axial direction of the developing sleeve 14a. And the generation of surplus agent can be prevented.

For safety, the pre-doctor 14 is similarly mounted on the other developing units 15, 16, and 17 shown in FIGS.
e may be provided. Although the present embodiment has been described with respect to an example in which a two-component developer including a toner and a carrier is used, the present invention can be applied to a developing device using a one-component developer including only a magnetic toner.

[0030]

According to the first or second aspect of the present invention, the developer conveyed by the developer carrying member is such that only the developer at both ends in the axial direction of the developer carrying member is previously determined by the second developer regulating member. After being scraped off by a predetermined amount, the first developer regulating member scrapes off the predetermined amount over the entire width in the axial direction of the developer carrier and is used for development, so that the generation of excess agent at the end of the developer carrier can be prevented. Thus, there is an effect that a stable image quality can always be maintained. Further , since the magnetic force on the surface of the developer carrier facing the second developer regulating member is set to 50 Gauss or less, the amount of the regulated developer is regulated stably without destabilizing the amount of developer. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a color copying apparatus according to an embodiment.

FIG. 2 is an enlarged view around a photoconductor and an intermediate transfer belt in FIG. 1;

FIG. 3 is a diagram illustrating a configuration of a developing device according to an embodiment and a magnetic force distribution on a surface of a developing sleeve.

FIG. 4 (a) is an explanatory diagram relating to a disposition position of a doctor. (B) is an explanatory view showing the relationship between the arrangement position of the doctor and the state of generation of surplus agent.

FIG. 5A is an angle θ of a doctor with respect to a developing sleeve.
FIG. 5 is an explanatory diagram relating to the flow of the developer when is equal to or more than 25 °. (B) shows an angle θ of the doctor with respect to the developing sleeve of 25 °.
FIG. 4 is an explanatory diagram regarding the flow of the developer in the following cases.

FIG. 6A is an explanatory diagram of the arrangement position of a predoctor in a circumferential direction of a developing sleeve and a flow of a developer. (B) is an explanatory view of the arrangement position of the predoctor in the developing sleeve axial direction.

FIG. 7 is an explanatory diagram relating to magnetic force setting in the vicinity of a predoctor.

FIG. 8A is an explanatory diagram of a surplus agent generated at an end of a developer carrying member. (B) is sectional drawing cut | disconnected by the plane along XX of (a).

FIG. 9 is an explanatory diagram of a scattering phenomenon of a surplus agent.

FIG. 10 is an explanatory diagram showing the relationship between the presence or absence of a surplus agent and the scattering phenomenon.

FIG. 11A is an explanatory diagram of a surplus developer in a developer carrier having a side seal disposed at an end; (B) is an explanatory view showing a state in which the side seal of the developer carrier of (a) is in contact with the surface of the latent image carrier.

FIG. 12A is an explanatory diagram showing a change in the speed of a latent image carrier when there is an excess agent. FIG. 4B is an explanatory diagram illustrating a change in the speed of the latent image carrier when there is no excess agent.

[Explanation of symbols]

 9 Photoconductor drum 14 Bk developing device 14a Developing sleeve 14b Developing paddle 14c Toner density sensor 14d Doctor 14e Predoctor

Claims (2)

(57) [Claims] A developer carrying member for supplying a developer to a latent image carrying member having a latent image formed on a surface thereof; a developer carrying member provided to face the developer carrying member; In a developing device comprising: a first developer regulating member for regulating a developer to a predetermined thickness; and a magnetic field generating means for forming a magnetic field of a desired magnetic force on the surface of the developer carrier, the developer regulating member A second developer regulating member that regulates the amount of the developer is disposed further upstream of the developer carrying member in the developer carrying direction and at both ends in the axial direction of the developer carrying member . For developer regulating members
Magnetic force on the surface of the developer carrier
A developing device characterized by setting . 2. A latent image carrier and a latent image formed on the latent image carrier.
A latent image forming means, and a latent image is formed by the latent image forming means.
A developing device that supplies a developer to the latent image carrier and develops the latent image carrier
In the image forming apparatus having the structure, the developing device according to claim 1 is used as the developing device.
An image forming apparatus.