JP3219906B2 - Developing device for image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention can be applied to an image recording apparatus that records an image on a sheet, such as a copying machine, a facsimile, and a printing machine. More specifically, the present invention relates to a developing device in which the latent image on the photoconductor is visualized by attaching toner in such an image recording apparatus.

[0002]

2. Description of the Related Art Conventionally, in a developing device of this type, a toner replenishing member supplies toner to a developing chamber through a toner replenishing port, and agitates the toner with a stirring member in the developing chamber. And a part of the toner replenished to the developing roller is blocked by the tip of the developing doctor to make a thin layer, while the surplus toner is collected by being sent to a separator, and the toner on the developing roller is collected. Is developed by adhering to the surface of a photoreceptor. In addition, this developing device has a screw case near the toner supply port, has a screw in the screw case, and conveys the toner collected by the separator in the axial direction of the photoconductor with the screw, and further supplies the toner to the stirring member. Then, it was supplied to the photoconductor again.

[0003]

However, conventionally, in such a developing device, when the toner is supplied to the developing chamber by the toner replenishing member, the screw is not supplied to the photosensitive member but remains in the developing chamber. The toner adheres to the toner supply port side of the case, and a large amount of toner often accumulates on the toner supply port side. Then, the large amount of accumulated toner falls at once by the vibration at the time of driving, and as a result, is supplied to the photoreceptor without being sufficiently agitated, which causes toner scattering, toner drop or large granularity. However, there has been a problem that image defects such as background dirt are caused.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a toner such as not sufficiently stirred from being supplied to a photoreceptor in a developing device, thereby causing problems such as an image defect and toner scattering. is there.

[0005]

For this purpose, the present invention has the following features.
A screw case 35 is provided near the toner supply port 20b for replenishing toner from the toner supply container 21 to the developing chamber 23. A screw 40 for transporting the collected toner in the photoconductor axial direction A is provided in the screw case 35. In the developing device 12 of the image recording apparatus provided with:
5 is characterized in that the height of the toner supply port 20b side is gradually reduced in the conveying direction A of the collected toner so that the toner easily overflows.

The screw case 35 is provided near the toner supply port 20b for supplying the toner from the toner supply container 21 to the developing chamber 23, as shown in the following embodiment, for example. Screw case 3
In the developing device 12 of the image recording apparatus provided with a screw 40 for conveying the collected toner in the photoconductor axial direction A in the toner supply port 20 of the screw case 35,
A toner outlet hole 45 is formed in the upper part on the b side in the transport direction A.

According to a third aspect of the present invention, there is provided a developing device according to the second aspect, as shown in the following embodiments, for example.
2, a guide projection 50 is formed below the toner outlet hole 45 of the screw case 35 to diffuse the toner flowing out of the toner outlet hole 45.

[0008]

According to the first aspect, at the time of development,
The recovered toner is transported in the axial direction A of the photoconductor through the screw case 35 by the screw 40. At this time, the toner in the screw case 35 overflows from the entire area in the transport direction A, and the toner attached to the toner supply port 20b side of the screw case 35 is removed.

According to the second aspect, at the time of development, the recovered toner is conveyed by the screw 40 through the screw case 35 in the axial direction A of the photoconductor. At that time, the collected toner flows out of the toner outlet hole 45 of the screw case 35,
The toner adhering to the toner supply port 20b side of the screw case 35 is removed.

According to the third aspect, the collected toner flowing out of the toner outflow hole 45 is diffused by the guide projection 50.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an image recording apparatus provided with a developing device according to an embodiment of the present invention, and shows a schematic configuration of a main part thereof.

Reference numeral 10 in the drawing denotes a drum-shaped photosensitive member provided substantially at the center of the apparatus main body (not shown). Around the photoreceptor 10, the charging device 11, the developing device 12, the transfer device 13, and the
An image density sensor 14 and a cleaning device 15 are provided.

Then, the front side of the apparatus main body (right side in FIG. 1)
Then, the sheet is conveyed to the lower side of the photoreceptor 10 as indicated by an arrow at a certain timing. On the other hand, the photoconductor 10 is driven in a clockwise direction. At this time, the surface of the photoconductor 10 is uniformly charged by the charging device 11 and irradiated with light from an optical writing device (not shown) to form an electrostatic latent image on the photoconductor 10. Form an image. This latent image is visualized by toner when passing through the position of the developing device 12. Then, the visible image is transferred onto a sheet conveyed below the photoreceptor 10 by the transfer device 13, and the transferred image is fixed by a fixing device (not shown) for recording. After the recording, the sheet is discharged to the outside of the apparatus main body, while the photosensitive member 1 is discharged.
The residual toner of 0 is removed by the cleaning device 15.

By the way, the developing device 12 described above is
As shown in FIG.
And a toner supply container 21 provided on the upper right side in FIG.

The developing tank 20 has a separator 22 mounted on the upper side of the inside thereof, and the inside of the developing tank 23 is vertically divided by the separator 22 to form a developing chamber 23 below. While a window 20a is provided on the photoconductor 10 side of the developing chamber 23,
On the opposite front side, a toner supply port 20b communicating with the toner supply container 21 is provided upward. And the developing chamber 23
Inside, a pair of upper and lower developing rollers 24.
25 are provided rotatably in contact with the photoconductor 10. Thus, the tip of the developing doctor 26 is brought into contact with the surface of the upper developing roller 24 from the upper side in the figure. On the other hand, a stirring roller 27 is rotatably provided below the toner supply port 20b, and the stirring roller 27 and the developing roller 24
A toner supply paddle 28 having a number of blades on the outer periphery is rotatably provided between the paddles 25. The stirring roller 27
A toner density sensor 29 is provided below the image sensor. And
The configuration is such that the driving of the toner supply roller 30 described later is controlled according to the detection output of the toner density sensor 29. Also,
The control reference value of the toner density sensor 29 is configured to be corrected according to the detection output of the image density sensor 14.

In the toner supply container 21, a toner supply roller (toner supply member) 30 is provided rotatably just above the toner supply port 20b. A screw 31 is provided above the toner supply roller 30. Although not shown, the toner supply container 21 is provided with a toner tank containing toner.

At the time of development, the toner is conveyed from the toner tank to the toner replenishing roller 30 by the screw 31, and the toner replenishing roller 30 further conveys the toner.
0b is supplied into the developing chamber 23. Then, the toner is stirred by the stirring roller 27 and sent to the paddle 28, and the paddle 28 replenishes the developing rollers 24 and 25. Thus, a part of the toner replenished to the developing roller 24 is blocked by the tip of the developing doctor 26 to make the layer thinner, and the surplus toner is sent to the separator 22 and collected. The developing rollers 24 and 25 electrostatically adhere the toner on the surface of the photoreceptor 10 to perform development.

In the developing device 12 described above, the separator 22 is elongated along the photoreceptor shaft 10a of the photoreceptor 10 and has a width that covers almost the entire developing chamber 23, as shown in FIG. Further, a guide plate portion 33 is provided which is gradually inclined downward from the front of the developing doctor 26 toward the stirring roller 27 in the drawing. Then, at the tip of the guide plate portion 33, a toner dropping port 34 which is long in the axial direction of the stirring roller 27 is provided.
Is provided. Further, as shown in FIG. 2, a large number of fins 33b are provided on the inclined surface 33a of the guide plate 33.
The fins 33b are arranged in parallel with each other, and are provided so that the toner dropping port 34 side is inclined obliquely toward the depth direction indicated by reference numeral A in the drawing. And the conveyance path 33c is formed between each fin 33b. Further, another conveying path 35a is provided from the innermost side of the guide plate 33 in the direction A. The separator 22 is formed by continuously providing the screw case 35 on the transport path 35a.

The screw case 35 is bent at a substantially right angle from the transport path 35a and formed to be long in the axial direction of the photoreceptor indicated by an arrow A in the figure, and formed in a U-shaped vertical section as shown in FIGS. Do it. And the screw case 35 is
The toner supply port 20b side (the right side in FIG. 1) is formed gradually lower in the photoconductor axial direction A. In addition, a toner outlet 35b is provided at the bottom (front side in FIG. 3) of the photosensitive member in the axial direction A.
Is provided. As shown in FIG. 2, a screw 40 is disposed in the screw case 35 in parallel with the photoconductor 10.

In the developing device 12, most of the collected toner collected on the separator 22 at the time of the above-described development is conveyed through the conveyance path 33c on the guide plate portion 33 to the back in the direction A to remove the toner. While the toner is dropped from the opening 34 onto the stirring roller 27, the innermost toner in the direction A is transferred to another transport path 35.
a, is fed into the screw case 35, is conveyed in the photoconductor axial direction A by the screw 40, and is dropped onto the stirring roller 27 from the toner outlet 35 b. Then, the collected toner is uniformly supplied to the stirring roller 27 from above in the axial direction.
The photosensitive member 1 is stirred by the stirring roller 27 as described above.
Supply to 0.

In the developing device 12, when toner is supplied into the developing chamber 23 by the toner supply roller 30, a part of the supplied toner adheres to the toner supply port 20b side of the screw case 35, There is a risk that a large amount will be deposited there. However, in the developing device 12 of the present invention described above, when the collected toner is transported through the screw case 35, a part of the toner overflows in the transport direction A beyond the toner supply port 20b side of the screw case 35 and overflows. The toner adhered to the toner supply port 20b side of the screw case 35 with the toner is removed.

In the illustrated embodiment, the height of the screw case 35 on the side of the toner supply port 20b is gradually reduced, and the collected toner overflows from the toner supply port 20b to remove the adhered toner. However, for example, FIG.
As shown in FIG.
A large number of toner outflow holes 45 are formed in the upper part on the 0b side in the transport direction A, and the collected toner passing through the screw case 35 flows out from the toner outflow holes 45, and the outflow toner supplies toner to the screw case 35. Mouth 2
It may be configured to remove the toner attached to the 0b side.

According to the present invention, when the toner outlet holes 45 are provided as described above, for example, as shown in FIG. 5, a C-shaped guide projection 50 is provided below each toner outlet hole 45 of the screw case 35. And a plurality of toner outlet holes 4
5 may be configured to diffuse the toner as indicated by the arrow.

In FIGS. 4 and 5, a large number of toner outlet holes 45 are formed in the transport direction A. For example, such a toner outlet hole is formed by one narrow slot continuous in the transport direction. You may.

[0025]

According to the first aspect of the present invention, a screw case is provided near a toner supply port for supplying toner from the toner supply container to the developing chamber, and the screw case is provided in the screw case. In a developing device of an image recording apparatus having a screw for transporting the collected toner in the axial direction of the photoreceptor, at the time of development, when the collected toner is transported through the screw case, a part of the recovered toner is supplied to the lower toner supply port side of the screw case. The toner that overflows from the toner supply port of the screw case is removed by the overflowing toner, whereby a large amount of such attached toner is accumulated, and the large amount of accumulated toner is dropped at once. It is possible to prevent problems such as image failure and toner scattering caused by being supplied to the photoconductor without being sufficiently stirred.

According to the second aspect of the present invention, the toner supplement
A screw case is provided near a toner supply port for replenishing toner from the supply container to the developing chamber, and in the developing device of the image recording apparatus having a screw for conveying the collected toner in the axial direction of the photoconductor in the screw case. When the collected toner is transported through the screw case, a part of the collected toner is caused to flow out of the toner outlet of the screw case, and the toner flowing out is used to remove the toner attached to the toner supply port side of the screw case. As a result, a large amount of such adhered toner is accumulated, and the large amount of accumulated toner falls at once and is not sufficiently agitated and supplied to the photoreceptor, thereby causing problems such as image defects and toner scattering. Can be prevented.

According to the third aspect of the present invention, the toner that has flowed out of the toner outflow hole of the screw case is diffused by the guide projection, so that the toner adhering to the toner supply port side of the screw case can be reduced by the outflow toner. It can be effectively removed.

[Brief description of the drawings]

FIG. 1 is an image recording apparatus including a developing device according to an embodiment of the present invention, and is a schematic configuration diagram of a main part thereof.

FIG. 2 is a plan view of a separator provided in the developing device.

FIG. 3 is a partial perspective view of a screw case of the separator.

FIG. 4 is a partial perspective view of another example of the screw case.

FIG. 5 is a partial side view showing a modified example of the screw case, showing the toner supply port side of the screw case.

[Explanation of symbols]

 Reference Signs List 12 developing device 20b toner supply port 23 developing chamber 35 screw case 40 screw 45 toner outlet hole 50 guide protrusion A photoconductor axial direction (transport direction)

Claims (3)

(57) [Claims] 1. A complement the toner from the toner supply container to the developing chamber
Install a screw case near the toner supply port to feed ,
In the developing device of the image recording apparatus provided with a screw for conveying the collected toner in the axial direction of the photoconductor in the screw case, the height of the screw case on the toner supply port side is gradually increased in the conveying direction of the collected toner. Developing device for an image recording apparatus, which is formed so as to gradually overflow and easily overflow. 2. A complement of toner from the toner supply container to the developing chamber
Install a screw case near the toner supply port to feed ,
In the developing device of the image recording apparatus provided with a screw for conveying the collected toner in the axial direction of the photoreceptor in the screw case, a toner outflow hole is formed in an upper portion of the screw case on the side of the toner supply port in the conveying direction. A developing device for an image recording apparatus. 3. The developing device for an image recording apparatus according to claim 2, wherein a guide projection for diffusing the toner flowing out of the toner outlet hole is formed below the toner outlet hole of the screw case.