JP2823240B2 - Developing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device that is used in a copying machine, a facsimile, a printer, and the like, and is detachable from an apparatus main body.

[Prior Art] Users are increasingly demanding a reduction in running costs in copying machines, facsimile machines, printers, and the like. On the other hand, a machine that responds to this request has been manufactured by performing some maintenance of the machine, which has been performed by a service person, by the user himself.

As one of these techniques for achieving user maintenance, a method has been proposed in which a developing device in which a developing unit and a toner storage unit are integrally formed, a copy is performed in accordance with a built-in toner amount, and then the entire developing device is replaced. ing.

In this case, the replacement of the developing device is prompted by detecting the amount of toner in the developing device and displaying the toner end on the main body. Further, it is prompted by displaying the usage limit to the user by a counter in which a predetermined number is set.

[Problems to be Solved by the Invention] The drawback of the above method is that copying is continued even if the toner end is displayed, or once the toner end is displayed and then reset or the main switch of the copying machine is turned off once, the following problem occurs. A certain number of copies are made until the toner end display. That is, if this operation is repeated, the toner concentration in the developer decreases, and the carrier adheres to the surface of the photoreceptor. And maintenance of the photoreceptor, necessitating new maintenance and not being able to achieve the targeted reduction in running cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device capable of preventing a problem due to use of the developing device after toner end and achieving a target of reducing running cost by user maintenance.

[Means for solving the problem]

An object of the present invention is to provide a developing device which is detachable from a main body, a rotatable developing roller, a magnet rotatably coaxially disposed inside the developing roller, and a fixing device for fixing the magnet at a developable position and a toner. A developing device having a fixing / releasing means for receiving the end signal to release the fixing state and disable development, wherein the fixing / releasing means in the developing device can be operated in conjunction with attachment / detachment to / from the main body. Achieved by disabling.

[Action]

The magnet is rotatable between a position where the developer is attracted to the surface of the developing roller and a position where the developer is not attracted. The fixing / releasing means usually fixes the magnet at a developable position (developer attracting position). The state is released, and the developing unit is rotated to the development impossible position (developer non-sucking position) to be in a development impossible state.

〔Example〕

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

FIG. 12 is a perspective view showing a copying machine and a developing device. The cover on the front side of the main body 1 is opened, and the developing device 2 is detachably attached.

FIG. 1 is a block diagram mainly showing a developing chamber 2 of a developing device according to the present invention. The developing device 2 includes a developing chamber 2a and a toner chamber 2b.
It is composed of

A developing roller 3 having a magnet 3a built therein;
A doctor 4 for regulating a developer layer on the developing roller 3 and a paddle wheel 5 for supplying a developer to the developing roller 3 are provided. A sensor 6 is mounted outside the developing chamber 2a. Further, a toner stirring member 7 is provided in the toner chamber 2b. The cover 8 of the developing device is welded to the side plate after assembling the components on the side plate for development. Also
8a is a cover hole.

FIG. 11 is a perspective view of the developing roller, and the developing roller 3
, The gear 3b is substantially integrally formed. A magnet 3a is arranged inside the developing roller 3, and a positioning plate 3c is fixed to one end of the magnet 3a. The gear 3b and the positioning plate 3c are provided outside the developing side plate.

FIG. 2 is a block diagram mainly showing the engagement state of the arm of the developing device according to the present invention, wherein 9, 10, 11 are arms, and 12 is a spring.

FIG. 3 is an explanatory view showing the disassembled parts and configuration of the part A in FIG. 2. The arms 10 and 11 try to rotate clockwise by springs 13 respectively, but the arm 10 is on the side plate or the arm 11 is The pin 11a engages with the hole 10a of the arm 10, and its rotation is prevented.

Reference numeral 14 denotes a bearing, 15 denotes a spring, and 11b denotes a step of the arm 11.

FIG. 4 is an exploded perspective view of the part B of FIG. 2. The gear 16 is about to rotate in the direction of the arrow by the torsion coil spring 17, but the pin 14a of the bearing part 14 and the arm 18 which rotates integrally with the gear 16 are shown. And rotation is stopped. At this time gear 16
Are in a positional relationship shown in the cross section.

 Hereinafter, the operation will be described.

FIG. 5 is an explanatory view showing a state in which the developing device is located outside the main body. In this case, the arm 10 and the semicircular portion 16a of the gear 16 are in the relationship shown in the drawing, and the arm 10 cannot rotate counterclockwise. It is. In this state, it is possible to prevent the user from pushing the arm 10 from the cover hole 8a by mistake and also prevent the arm 10 from rotating due to vibration during transportation. 2c is a development side plate.

FIG. 6 is an explanatory view of a state in which the developing device is set in the main body. When the developing device 2 is set in the direction of the arrow, the main body 1 is set.
The rack 20 and the gear 16 provided in the gear mesh with each other and rotate half a turn,
The semicircular portion 16a is in the state shown in the figure, whereby the arm 10 can rotate in the counterclockwise direction. When the developing device 2 is taken out of the main body 1 by color change or the like, the state returns to the state shown in FIG.

FIG. 7 is an explanatory view showing a state in which the solenoid is operated. The arm 9 and the arm 11 are rotated counterclockwise by the operation of the solenoid 19, and the rotation of the arm 9 is prevented by the step 11b of the arm 11. The spring 12 rotates counterclockwise.

FIG. 8 is an explanatory view of a state where the developing device is pulled out from the main body.

FIG. 9 is a side view of the developing device when the solenoid is actuated, showing the arm 9 disengaged from the arm 11 and its shaft 9a.
The movement is transmitted to the fixed claw 9b shown in FIG. 10 attached to the outside of the opposite side plate.

FIG. 10 is an explanatory view showing a mechanism for controlling the rotation of the magnet, in which the magnet 3a fixed at a predetermined angle by a fixing claw 9b.
The positioning plate 3c integrated therewith is rotated clockwise by the spring 21 to rotate the magnet 3a. Therefore, the developer supplied from the paddle wheel 5 cannot adhere to the developing roller 3, and as a result, it becomes impossible to visualize the electrostatic latent image on the photoconductor.

The arm 9 shown in FIG. 9 cannot be reset unless the welded portion of the cover 8 is broken. Therefore, the developing device 2 which has become unusable due to the toner end cannot be used again.

The fixing / releasing means described in the claims includes the positioning plate 3c, the arms 9, 10, 11, the solenoid 19, the spring 21, and the like.

〔The invention's effect〕

As described above, according to the present invention, it is possible to clearly notify the user of the toner end state when the developing device has run out of toner, and to prevent the toner from being reused by mistake. Further, when the developing device is removed from the main body, by disabling the fixing / releasing means for disabling development, the means for disabling development is accidentally activated,
Still, it is possible to reliably prevent a usable developing device from becoming unusable.

[Brief description of the drawings]

FIG. 1 is a block diagram mainly showing a developing chamber of a developing device according to the present invention, FIG. 2 is a block diagram mainly showing an engaged state of an arm of the developing device according to the present invention, and FIG. FIG. 4 is an exploded perspective view of part B of FIG. 2, FIG. 5 is an explanatory view of a state in which the developing device is outside the main body, and FIG. 6 is a diagram in which the developing device is mounted on the main body. FIG. 7 is an explanatory view of a set state, FIG. 7 is an explanatory view when a solenoid is operated, FIG. 8 is an explanatory view of a state in which a developing device is pulled out from a main body, and FIG.
The figure is a side view of the developing device when the solenoid operates,
FIG. 10 is an explanatory view showing a mechanism for controlling rotation of a magnet, FIG. 11 is a perspective view of a developing roller, and FIG. 12 is a perspective view showing a copying machine and a developing device. 3 ... developing roller, 3a ... magnet, 3c ... positioning plate, 9,
10,11 ... arm, 19 ... solenoid, 21 ... spring.

Claims (1)

(57) [Claims] 1. A developing device detachable from a main body, comprising: a rotatable developing roller; a magnet rotatably coaxially disposed therein; and a magnet fixed to a developable position; A developing device having a fixing / releasing means for releasing the fixing state in response to a toner end signal and disabling development, wherein the fixing / releasing means in the developing device can be operated in conjunction with attachment / detachment to / from the main body. And a developing device for disabling the developing device.