JPH0311379A - Developing device - Google Patents

Abstract

PURPOSE:To prevent trouble due to the use of a developing device after running- out of toner by providing a magnet coaxially arranged in a developing roll and a fixing and releasing means which fixes this magnet in a developable position and releases the fixing state by a toner end signal to disable development. CONSTITUTION:A rotatable developing roll 3, a magnet 3a rotatably and coaxially arranged in this roll 3, and fixing and releasing means 9 to 11 which fix the magnet 3a in the developable position and receive the toner end signal to release the fixing stage of the magnet 3a to a undevelopable position are provided. That is, the magnet 3a is rotated to the position where developer is attracted to the surface of the developing roll 3, and the position where developer is not attracted there, and fixing and releasing means 9 to 11 normally fix the magnet 3a in the developable position and release it to the undevelopable position at the time of running-out of toner. Thus, the replacement time of the developing device is clearly reported to a user to prevent trouble due to a lack of toner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device that is used in copying machines, facsimile machines, printers, etc. and is detachable from the main body of the device.

[Conventional technology]

Users are increasingly demanding lower running costs for copiers, facsimile machines, printers, etc.

In contrast, machines are being manufactured to meet this demand by allowing users to perform some of the machine maintenance themselves, which has traditionally been done by service personnel.

As one of these user maintenance achievement technologies, we created a developing device that integrated a developing section and a toner storage section.
A method has been proposed in which the entire developing device is replaced after copying has been made in accordance with the amount of toner contained therein.

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

[Problem to be solved by the invention]

The disadvantage of the above method is that even if toner end is displayed, copying continues, or after toner end is displayed, if you reset the machine or turn off the main switch of the copier, a certain number of copies will be made until the next toner end display. Copying is to be done.

In other words, if this is repeated, the toner concentration in the developer will decrease, carriers will adhere to the surface of the photoreceptor, staining the inside of the machine, causing leaks in the transfer charger, and carriers getting between the photoreceptor and cleaning blade, causing the blade to become damaged. This caused chipping and scratches on the photoreceptor, necessitating new maintenance, and the goal of reducing running costs could not be achieved.

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device that can prevent problems caused by using the developing device after the toner has run out, and can achieve the goal of reducing running costs through user maintenance.

[Means to solve the problem]

The above object is to provide a developing device that is integrally provided with a developing chamber and a toner chamber and is removably attached to a main body, a rotatable developing roller, a magnet rotatably coaxially disposed inside the developing device,
This is achieved by fixing the magnet at the development possible position and by providing a fixing/releasing means for receiving a toner end signal and releasing the fixation of the magnet at the development non-development position.

[Effect]

The magnet acts to rotate between a position where it attracts developer and a position where it does not attract developer on the surface of the developing roller, and the fixing/releasing means usually fixes the magnet at a position where development is possible (developer adsorption position) and when the toner runs out. is released (rotated) to the development disabled position (developer non-adsorption position).

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 12 is a perspective view showing the copying machine and the developing device, and is constructed so that the developing device 2 can be attached and removed by opening the cover on the front side of the main body l.

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

Inside the developing chamber 2a, a developing roller 3 with a built-in magnet 3a, a doctor 4 regulating the developer layer on the developing roller 3,
A paddle wheel 5 for supplying developer to the developing roller 3 is provided. Further, a sensor 6 is attached to the outside of the developing chamber 2a.

Further, a toner stirring member 7 is provided within the toner chamber 2b. The cover 8 of the developing device is welded to the side plate after each component is assembled to the side plate.

Further, 8a is a cover hole portion.

FIG. 11 is a perspective view of the developing roller, and shows the developing roller 3.
The gear 3b is substantially integrated.

Further, 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 positioning plate 3c are provided on the outside of the developing side plate.

FIG. 2 is a block diagram mainly showing the state in which the arms of the developing device according to the present invention are held together; 9.10.11 is an arm;
2 is a spring.

FIG. 3 is an explanatory view showing the exploded parts and structure of section A in FIG.
Or, for the arm 11, the pin 11a is the hole 10a of the arm 10.
and its rotation is prevented.

In addition, 14 is a bearing part, 15 is a spring, and Llb is an arm 11.
This is the stepped part.

FIG. 4 is an exploded perspective view of part B in FIG. 2. The gear 16 tries to rotate in the direction of the arrow by the torsion coil spring 17, but the arm 18 rotates together with the pin 14a of the bearing 14 and the gear 16. is in contact and rotation is prevented. At this time, the semicircular portion 16a of the gear 16 is in the positional relationship shown in the cross section.

The operation will be explained below.

FIG. 5 is an explanatory diagram of 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 as shown, and the arm 10 cannot be rotated counterclockwise. It is. In this state, the arm IO is prevented from rotating due to the user accidentally pushing the arm 10 through the cover hole 8a or due to vibration during transportation. Note that 2C is a developing side plate.

FIG. 6 is an explanatory view of the developing device set in the main body, and when the developing device 2 is set in the direction of the arrow, the rack 20 provided in the main body 1 and the gear 16 engage and rotate half a rotation, and the semicircular portion 16a is in the state shown in the figure, and thereby arm IO can rotate counterclockwise. Further, when the developing device 2 is taken out from the main body 1 for a color change or the like, it returns to the state shown in FIG. 5.

FIG. 7 is an explanatory diagram of a state in which the solenoid is activated,
The operation of the solenoid 19 causes the arm 11 to rotate counterclockwise by 10 degrees, and the arm 9, which has been prevented from rotating by the stepped portion 11b of the arm 11, rotates counterclockwise by the spring 12.

FIG. 8 is an explanatory diagram of a state in which the developing device is pulled out from the main body.

FIG. 9 is a side view of the developing device when the solenoid is activated, showing the arm 9 detached from the arm 11 and its shaft 9.
a, the movement is transmitted to the fixing claw 9b shown in FIG. 1O, which is attached to the outside of the opposite side plate.

FIG. 10 is an explanatory diagram showing a mechanism for controlling the rotation of the magnet, in which the magnet 3 is fixed at a predetermined angle by the fixing claw 9b.
The positioning plate 3C integrated with the magnet 3a is rotated clockwise by the spring 21, thereby rotating 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 photoreceptor.

Note that the arm 9 shown in FIG. 9 cannot be reset without breaking the welded portion of the cover 8. Therefore, once the developing device 2 becomes unusable due to the toner end, it cannot be used again.

Note that the fixing/releasing means described in the claims include the temporary positioning 3C, the arms 9, 10, 11, the solenoid 19,
The spring 21 etc. constitute this.

〔Effect of the invention〕

As described above, according to the present invention, by changing the angle of the magnet in the developing roller to disable image formation when toner runs out, it is possible to clearly notify the user when it is time to replace the developing device. By disabling a developing device that has run out of toner, it is possible to prevent carrier adhesion caused by insufficient toner and the resulting problems.
It is possible to provide a developing device that does not require the user to bear unnecessary maintenance costs.

[Brief explanation of drawings]

FIG. 1 is a block diagram mainly showing the developing chamber of the developing device according to the present invention, FIG. 2 is a block diagram mainly showing the engaged state of the arms of the developing device according to the present invention, and FIG. 3 is a block diagram mainly shown in FIG. FIG. 4 is an exploded perspective view of the section B in FIG. 2, FIG. 5 is an explanatory diagram showing the developing device located outside the main body, and FIG. Figure 7 is an explanatory diagram when the solenoid is activated, Figure 8 is an explanatory diagram when the solenoid is activated.
The figure is an explanatory diagram of the developing device pulled out from the main body, Figure 9 is a side configuration diagram of the σ developing device when the solenoid is activated, Figure 10 is an explanatory diagram showing the mechanism for controlling the rotation of the magnet,
FIG. 1 is a perspective view of the developing roller, and FIG. 12 is a perspective view showing the copying machine and the developing device. 3...Developing roller, 3a...Magnet, 3C...Positioning plate, 9.10.11...Arm, 19...Solenoid, 21...Spring. Figure 1 Figure 2

Claims (1)

[Claims] A developing device that has a developing chamber and a toner chamber integrated and is removable from the main body, has a rotatable developing roller, a magnet coaxially and rotatably arranged inside the developing roller, and this magnet is fixed at a position where development can be performed. A developing device further comprising a fixing/releasing means for releasing the fixed state upon receiving a toner end signal and disabling development.