JPH0750756Y2 - Development device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a developing device used in a printer, a copying machine or the like.

[Conventional technology]

2. Description of the Related Art Conventionally, there is a two-component developing system as a developing device used in a printer or a copying machine. The conventional developing device has a structure as shown in FIG.

In the figure, the developing device 1 includes a developing chamber 2 and a toner storage chamber 3.
Are provided above and below via a communicating portion 4, and a developing roll 5 and a stirring roll 6 are provided below the developing chamber 2. The developing roll 5 faces the photosensitive drum 7, and a predetermined amount of developer 8 is introduced into the developing chamber 2.

The developer 8 is a mixture of a carrier made of iron oxide powder or ferrite powder and a toner made of styrene, acryl, polyethylene, dye or the like in a fixed amount ratio.

Further, at the position of the communication portion 4, the toner supply roll 9 is formed so as to close the lower part of the hopper below the toner storage chamber 3.
Is rotatably provided, and this toner supply roll 9
The rotary shaft 9a is composed of a rotary shaft 9a and a porous elastic body 9b which is integrated with the rotary shaft 9a and whose peripheral surface is made of a member having a porous property and elasticity (for example, a cylindrical sponge member). Therefore, the communicating portion 4 is always closed by the close contact of the peripheral surface of the porous elastic body 9b.

In the developing chamber 2, a toner sensor 10 including a piezoelectric element (not shown) is provided at a predetermined height position (level detection position) as a means for generating a toner replenishment signal, and faces the developing roll 5. And a doctor blade 11 is provided.

In the above, the developer 8 in the developing chamber 2 is agitated by the rotation of the agitating roll 6, the developer 8 is conveyed to the surface of the rotating developing roll 5 by magnetic force, and is regulated to a predetermined thickness layer by the doctor blade 11. The developed developer 8 adheres to the surface of the developing roll 5. Then, the developing roll 5 is formed on the surface of the photosensitive drum 7 by an electrophotographic process.
Only the toner adheres from the eight layers of the developer on the surface of the sheet by electrostatic attraction. By repeating this, when the amount of toner in the developer 8 decreases, the amount of toner adhering to the surface of the photosensitive drum 7 also decreases and the image density decreases. Replenish.

The toner 12 to be replenished is accommodated in the toner accommodating chamber 3 in an appropriate amount, for example, as shown by a chain line, and the toner supply roll 9 rotates a certain amount in the arrow direction in response to the signal generation of the toner sensor 10. . Then, the toner that has entered the concave portion (not shown) due to the foaming of the surface of the toner supply roll 9 causes the surface of the toner supply roll 9 to develop in the developing chamber 2.
When it is exposed to the side, the toner 12a falls from the surface of the toner supply roll 9 by natural fall as shown in the figure, and the surface of the toner supply roll 9 is squeezed by the squeezing part 4a of the communication part 4, The toner adhering to the surface is scraped off into the developing chamber 2 as the toner 12b.

A lid 13 is provided on the upper surface of the toner storage chamber 3 so as to be openable and closable.

On the other hand, in the developing device 1 having the above-described configuration, the developing chamber 2 is pre-filled with a certain amount of the developer 8 during the production process,
When the user uses, for example, a printer in which the developing device 1 is set, the user opens the lid 13 and fills only the toner 12 into the toner storage chamber 3 for use.

[Problems of conventional technology]

However, in the developing device 1 described above, the device in which the developing device 1 is set, or the developing device 1 transported for replacement or the like is turned upside down as shown in FIG. It may be treated as orientation. In this case, the developer 8 filled in the developing chamber 2 does not pass through the toner supply roll 9 in a rest state, but when the developer 8 is subjected to vibrations or impacts, the developer 8 is changed to the arrow 8a as shown in the figure. As shown by, the toner may be leaked into the toner storage chamber 3 after passing through the toner supply roll 9 or between the toner supply roll 9 and the communicating portion 4.

The porous elastic body 9b of the toner supply roll 9 has a foam cell number of about 20 to 60 (cells / 25 mm), and the particle size of the developer 8 is 10 to 100 μm.
Since the specific gravity is m (true specific gravity of about 7), the above leakage phenomenon appears when vibration is applied to the developing device 1 for a long time. Therefore, the leaked developer 8b is shown on the inner surface of the lid 13 in FIG.

Therefore, when a certain amount of the developer 8 is filled in the developing chamber 2 and a part of the developer 8 leaks into the toner accommodating chamber 3 due to the above reason, as shown in FIG. When using, the level L of the developer 8 in the developing chamber 2 becomes lower than the original filling position (two-dot chain line position) L ₀ , and the developer 8 in the developing chamber 2 becomes insufficient. Then, a large amount of toner 12a, 12b is replenished to make up for this shortage of developer 8. As a result, there is a problem in that the ratio of the developer 8 changes depending on the decreased carrier and the increased toner, which causes an abnormal increase in image density and scumming.

Further, the reduced carrier in the developer 8 cannot capture the toner, and the toner is scattered to the outside of the developing device 1 to cause the malfunction of the developing device 1 and the adhesion of the scattered toner to the transfer sheet. However, there was a drawback in that

Further, as described above, if the developer 8 leaks into the toner storage chamber 3, it leaks to the inner surface of the lid 13 when the lid 13 of the toner storage chamber 3 is opened in the early stage of use of the developing device 1.
There is a risk that the accumulated developer 8b may spill out of the toner storage chamber 3 and pollute the environment.

[Purpose of device]

In view of the above-mentioned conventional problems, the present invention can prevent the developing device from being turned sideways or upside down during handling during transportation, unloading, or loading.
An object of the present invention is to provide a developing device capable of preventing a developer of a component developing system from leaking from a developing chamber into a toner containing chamber and maintaining stable image transfer.

[Key points of device]

According to the present invention, the above-mentioned object is rotatable in a developing chamber for accommodating a developer composed of a carrier and toner, a toner accommodating chamber for accommodating replenishment toner, and a communicating portion between the developing chamber and the toner accommodating chamber. A toner supply roll for supplying the replenishment toner carried through the porous portion to the developing chamber with rotation in a predetermined direction, and a peripheral surface of the toner supply roll. A shutter member that can move along the peripheral surface of the toner supply roll between a closed position that is located between the supply roll and the developing chamber and that can close the communication part, and a retracted position that releases the closed position. And when moving the shutter member from the closed position to the retracted position,
Engaging means for stopping the shutter member at the retracted position, and a shutter member provided on the shutter member for contacting the peripheral surface of the toner supply roll and rotating the toner supply roll in the predetermined direction based on the contact. The present invention is achieved by providing a developing device, which is provided with an abutting portion that moves the shutter member from the closed position to the retracted position in conjunction with each other.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a developing device according to the present invention. In addition,
The same members as those of the developing device 1 described in the above-mentioned conventional example are designated by the same reference numerals, and a duplicate description will be omitted.

In the figure, the developing device 14 includes a developing chamber 15 provided with a developing roll 5 and a stirring roll 6 in a lower portion, and a toner accommodating chamber 17 provided in an upper portion of the developing chamber 15 via a communicating portion 16.
And a toner supply roll 9 rotatably interposed in the communicating portion 16, and a toner supply roll 9 rotatably supported at both ends of a rotation shaft 9a of the toner supply roll 9 along the peripheral surface of the porous elastic body 9b. Further, the shutter member 18 is formed with a size capable of closing the lower opening of the communication portion 16.

In addition, an ironing part 18a is provided on one side of the shutter member 18.
Is formed, and the tip of the ironing portion 18a is abutted on the peripheral surface of the porous elastic body 9b so as to fit into it.

On the other hand, the communication portion 16 is formed with a space 16a in which the shutter member 18 can be retracted.
At the lower part of 6a, there is provided a seal member 19 whose tip is slidably brought into pressure contact with the surface of the shutter member 18.

The seal member 19 may be omitted when the lower portion of the space 16a is formed so as to be directly slidably adhered to the surface of the shutter member 18.

Further, in the above description, the peripheral surface of the toner supply roll 9 is always in contact with one side of the inner surface of the communication part 16 (opposite side of the space 16a), and the shutter member 18 has the squeezing part 18a on the surface of the toner supply roll 9. Since the toner supply roll 9 is abutted so as to be difficult to insert, by rotating the toner supply roll 9 counterclockwise in the drawing, the shutter member 18 can close the lower opening surface of the communication portion 16 as illustrated.

FIG. 2 is a view showing a state in which the developing device of this embodiment is turned upside down.

In the figure, when the developing device 14 is turned upside down for transportation or the like, the developer 8 previously filled in the developing chamber 15 falls to the communicating portion 16 side. However, since the toner supply roll 9 is provided with the shutter member 18 at a position that closes the outlet side of the communication portion 16, the developer 8 will sway on the surface of the toner supply roll 9 even if the developing device 14 is vibrated. It does not leak to the toner storage chamber 17 side.

FIG. 3 is a view showing a usage state of the developing device of this embodiment.

In the figure, the developing device 14 is set in a main body (not shown), and then the toner 12 is replenished into the toner storage chamber 17 by an appropriate amount. After that, when the toner supply roll 9 rotates in the direction of the arrow A by the first toner replenishing operation, the shutter member 18 having the squeezing portion 18a, which is in contact with the surface of the toner supply roll 9, is pressed by the contact friction. It follows and rotates in the same direction as the supply roll 9. Then, the other side of the shutter member 18 (the tip in the rotation direction) is a communicating portion.
It hits the upper end 16b of the space 16 and stops rotating.
In this state, the outlet of the communicating portion 16 is opened, and the toner supply roll 9 is squeezed by the squeezing portion 18a of the shutter member 18. Further, at this time, since the tip of the seal member 19 is pressed against the surface of the shutter member 18, the developer 8 attached to the surface of the shutter member 18 is scraped off into the developing chamber 15.

Therefore, the toner 12 is replenished into the developing chamber 15 by rotating the toner supply roll 9 as described in the conventional example, and the toner 12 can be replenished little by little.

[Effect of device]

As described in detail above, according to the present invention, the shutter for opening the outlet of the toner supply roll, which is interposed in the communication portion between the developing chamber and the toner storage chamber, by the normal rotation of the toner supply roll. Although it has a simple structure due to the provision of the member, even if the developing device that is transported or loaded and unloaded by shipping is tilted upside down, the developer filled in the developing chamber remains Leakage into the toner storage chamber can be reliably prevented, and stable image formation can be maintained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the developing device of this embodiment, FIG. 2 is a view showing a state in which the developing device of this embodiment is turned upside down, and FIG. 3 is a usage state of the developing device of this embodiment. FIG. 4 is a cross-sectional view showing a conventional developing device, FIG. 5 is a view showing a state where the conventional developing device is turned upside down, and FIG. 6 is a use of the conventional developing device. It is a figure which shows a state. 8 ... Developer, 9 ... Toner supply roll, 9b ... Porous elastic body, 14 ... Developing device, 15 ... Developing chamber, 16 ... Communication part, 17 ... Toner accommodating chamber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-50-159738 (JP, A) JP-A-56-121067 (JP, A) Actually open 61-167666 (JP, U) Actually open 1- 64658 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A developing chamber for accommodating a developer composed of a carrier and toner, a toner accommodating chamber for accommodating replenishment toner, and a peripheral portion which is rotatably interposed in a communicating portion between the developing chamber and the toner accommodating chamber. A surface is formed of a porous elastic body, and a toner supply roll that replenishes the replenishment toner carried through the porous portion with the rotation in a predetermined direction to the developing chamber, the toner supply roll, and the toner supply roll. A shutter member which is located between the developing chamber and a communication position, and is movable along the peripheral surface of the toner supply roll; When the member moves from the closed position to the retracted position, an engaging unit that stops the shutter member at the retracted position, and the shutter member, which is provided on the shutter member, abuts on the peripheral surface of the toner supply roll to make a corresponding contact. Zui the developing device characterized in that it comprises a said abutment portion for moving the shutter member in interrelation with the toner supply roll is rotated in the predetermined direction to the retracted position from the closed position.