JPH04323678A - Developing device for image recorder - Google Patents

Abstract

PURPOSE:To obtain the developing device for the image recorder where an excessive load is not exerted on a rotational shaft by providing a torque limiter mechanism between an agitator and the rotational shaft. CONSTITUTION:The rotational shaft 18 is rotated only in the direction X by a driving gear 20 fixed to the rotational shaft 18. Toner is agitated by the agitator 12 inserted and held between a pressing spring part 22a and an auxiliary spring part 22b of a leaf spring 22 being rotated synchronized with the rotational shaft 18. If the excessive load is put on the agitator 12 here, since the rotational shaft 18 is rotated in the direction of X, the pressing spring part 22a of the leaf spring 22 deflects and runs off from the agitator 12, and the leaf spring 22 is rotated once and returned. In this case, because the rotational shaft 18 is continuously rotated in the direction X, the auxiliary spring part 22b is first brought into contact with the agitator 12, and the agitator 12 is jumped over. As the result, the leaf spring 22 is returned to an initial state of slackness, that is the normal state. The initial normal state is completely recovered here by eliminating the cause for the excessive load.

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 recording device such as a facsimile machine, printer, or copying machine, and more particularly to a developing device for an image recording device having an agitator for stirring toner in a toner hopper.

0002

2. Description of the Related Art Conventionally, an image recording apparatus such as a printer has a developing device that attaches toner to an electrostatic latent image to form a visible image. In this developing device, toner for visualization is filled into a toner hopper, but since the toner will stick if left in the filled state, an agitator is provided to agitate the toner.

Conventional developing devices of this type of image recording apparatus are disclosed in, for example, Japanese Patent Application Laid-open No. 62-7067 and Japanese Patent Application Laid-open No. 62-7067.
There is something described in the publication No. 2-86382, etc., and it is shown in Figure 3.
It is shown as follows. In the figure, toner 11 (either magnetic or non-magnetic) in a toner hopper 10 is conveyed to a toner supply roller 13 by an agitator 12. The toner conveyed to the toner replenishment roller 13 is moved as the toner replenishment roller 13 rotates clockwise.
It adheres to the developing roller 14. The toner adhering to the developing roller 14 rotates as the developing roller 14 rotates clockwise, and during this time it is regulated into a uniform thin film by the blade 15. This toner comes into contact with an electrostatic latent image formed on a photoreceptor of an image recording device (not shown), adheres to the electrostatic latent image, and becomes a visible image. The toner that did not contribute to development returns to the toner supply roller 13 again.

[0004] Toner is replenished into the toner hopper 10 by a toner cartridge 16 . That is, by attaching the toner cartridge 16 to the upper part of the toner hopper 10 and winding up the toner lid tape 17, the toner inside falls down and the toner 11 is replenished. The toner 11 in the toner hopper 10 is agitated by an agitator 12.

[0005] The agitator 12 is caulked and fixed to a rotating shaft 18 that rotates within the toner hopper 10. The rotating shaft 18 is rotated in one direction by a screwed drive gear (not shown).

[0006]

However, in the developing device of such a conventional image recording apparatus, when installing the toner cartridge 16, the toner cover tape 1
However, if the toner lid tape 17 is not completely wound, the toner lid tape 17 will hang down and the tape 1
7 is entangled with the agitator 12 to fix the movement of the agitator 12 and rotating shaft 18. Therefore, there is a problem in that the drive gear screwed to the rotating shaft 18 is overloaded and damaged.

[0007] Accordingly, an object of the invention as set forth in claim 1 is to provide a developing device for an image recording apparatus that does not apply an excessive load to the rotating shaft by providing a torque limiter mechanism between the agitator and the rotating shaft. There is. Further, the invention as set forth in claim 2 provides a developing device for an image recording apparatus in which an agitator can be rotated about the axis of the rotating shaft by wrapping both end portions of an elastic member formed of a wire spring material around the rotating shaft. The purpose is to

[0008]

[Means for solving the problem] The invention according to claim 1 includes:
In order to achieve the above object, in a developing device of an image recording apparatus, which includes a rotating shaft that rotates within a toner hopper, and an agitator that is attached to the rotating shaft and agitates the toner within the toner hopper, the agitator is connected to the rotating shaft. The agitator is rotatably attached to the rotary shaft, and an elastic member for positioning the agitator with respect to the rotary shaft is fixed to the rotary shaft.

[0009] Furthermore, in order to achieve the above object, the invention as claimed in claim 2 includes forming the agitator from a wire spring material, processing both end portions of the wire spring material into a tendril shape, and rotating the tendril portion. It is characterized by being tied around the shaft.

0010

[Operation] In the invention according to claim 1 having the above configuration, the agitator attached to the rotating shaft is freely rotatable about the rotating shaft, and the agitator is rotated by the elastic member separately fixed to the rotating shaft. Positioned relative to the axis. Further, in the invention as set forth in claim 2 having the above configuration, both end portions of the agitator formed of a wire spring material are processed into a tendril shape, and the tendril-like portions are entangled around the rotating shaft.

[0011]

EXAMPLES The present invention will be explained below based on examples. FIG. 1 is a perspective view showing a developing device of an image recording apparatus according to an embodiment of the invention. In this embodiment, the same components as those in the conventional example are designated by the same reference numerals, and detailed explanation thereof will be omitted.

First, the configuration will be explained. In the figure, the rotating shaft 18 has a drive gear 20 fixed thereto by screws or the like, and rotates in the x direction within a toner hopper formed by a hopper frame 21 . The agitator 12 is connected to the rotating shaft 1
8, and is positioned with respect to the rotating shaft 18 by a leaf spring 22 as an elastic member. That is, the leaf spring 22 is fixed to the rotating shaft 18 with a screw 23, and the agitator 12 is sandwiched between a pushing spring part 22a that pushes in the x rotational direction and an auxiliary spring part 22b that contacts from the opposite direction, so that it can rotate freely. Fix the agitator 12. In this embodiment, the elastic member is formed of a plate spring, but it may be formed of a wire spring, a plastic material, or the like.

The agitator 12 is made of a wire spring material, and as shown in the figure, both ends of the wire spring material are bent into a vine shape. By wrapping the vine-shaped portion 12a around the rotating shaft 18, the agitator 12 can be freely rotatably attached to the rotating shaft 18. In addition, agitator 1
2 is an E-ring 2 placed on the outside of both tendrils 12a.
4 prevents displacement in the axial direction.

Next, the operation will be explained. The drive gear 20 fixed to the rotating shaft 18 causes the rotating shaft 18 to rotate only in the direction of arrow x. With this rotation, the agitator 12 held between the push spring section 22a and the auxiliary spring section 22b of the plate spring 22 rotates in synchronization with the rotating shaft 18, and the toner is agitated. A cross-sectional view of the leaf spring 22 during normal operation is shown in FIG. 2(a). Here, as explained in the prior art, if the toner lid tape is wrapped around the agitator 12 and an excessive load is applied to the agitator 12, the agitator 12 becomes unable to rotate. However, since the rotating shaft 18 rotates in the x direction, the pushing spring portion 22a of the leaf spring 22 is deflected and removed from the agitator 12, as shown in FIG. 2(b). FIG. 2(c) shows a state in which the leaf spring 22, which has come off from the agitator 12, has made one rotation and returned. In FIG. 2(c), since the rotating shaft 18 continues to rotate in the x direction, the auxiliary spring portion 22b first contacts the agitator 12 and climbs over the agitator 12. As a result, the leaf spring 22 returns to the initial state of deflection, that is, the normal state shown in FIG. 2(a). At this point, by removing the cause of the overload, the initial normal state is completely restored.

As described above, in this embodiment, since the agitator 12 and the rotating shaft 18 can be connected by using the leaf spring 22 as a torque limiter mechanism, even if the agitator 12 becomes unable to rotate, the rotating shaft 18 is Only a predetermined torque, that is, a reaction force by the leaf spring 22 acts, and the rotating shaft 18,
Parts related to toner agitation, such as the drive gear 20, will not be damaged.

Furthermore, by keeping the amount of deflection of the leaf spring 22 within the allowable stress, plastic deformation can be prevented and the initial elastic properties can be maintained. Therefore, even if an overload occurs on the agitator 12, the normal toner agitation operation can be restored by removing the cause of the overload and setting the leaf spring 22 to its initial state. Therefore, work such as replacing parts is not required, which is highly effective in terms of maintenance.

Furthermore, in this embodiment, since the torque limiter mechanism can be constructed by the plate spring 22, space can be saved, and since there are fewer mechanical parts, it is also possible to reduce costs. Further, by processing both ends of the agitator 12 formed of a wire spring material into a vine shape and wrapping the vine-like portions 12a around the rotating shaft 18, the agitator 12 can be attached to freely rotate around the rotating shaft 18. Can be done.

[0018] To give an example of actual measurement data obtained when the present invention is applied to a current model, the destructive torque of the drive gear 20 is approximately 15 kg/cm to 20 kg/cm due to toner agitation by the agitator 12 during normal toner replenishment. The load torque was 0.6 kg·cm.

Further, when the thickness t of the leaf spring 22 is set to 0.2 or 0.3 mm, the driving torque and maximum driving torque of each leaf spring are as follows. Note that the driving torque refers to the driving torque caused by the pushing spring portion 22a alone in the state shown in FIG. 2(a). Moreover, the maximum driving torque indicates the driving torque when the auxiliary spring part 22b and the pushing spring part 22a simultaneously contact the fixed agitator 12 and come off again in the state shown in FIG. 2(c).

[0020]
t=0.2 t=0.3
Driving torque (kg/cm) 0.35~0.
4 0.9~1.0 Maximum driving torque (kg・cm
) 0.5 1.1

0
021]

As described above, according to the developing device for an image recording apparatus according to the invention as set forth in claim 1, the agitator attached to the rotating shaft is freely rotatable about the rotating shaft, and By positioning the agitator with respect to the rotating shaft using an elastic member that is separately fixed to the rotary shaft, the elastic member can be used as a torque limiter mechanism to connect the agitator and the rotating shaft. Only a predetermined torque, that is, a reaction force by the elastic member acts on the toner, and damage to parts related to toner agitation can be prevented.

According to the developing device of the image recording apparatus according to the second aspect of the invention, both end portions of the agitator formed of a wire spring material are processed into a tendril shape, and the tendril-like portions are entangled around the rotating shaft. By attaching the agitator, the agitator can be attached to rotate freely around the rotation axis.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a developing device of an image recording apparatus according to an embodiment of the invention as set forth in claim 1 or 2. FIG.

FIG. 2 is a sectional view showing the operation of a leaf spring, and FIG.
1 is a cross-sectional view during normal operation, FIG. 6(b) is a cross-sectional view in an overloaded state, and FIG. 10(c) is a cross-sectional view showing a state in which the leaf spring, which has come off the agitator due to overload, has made one revolution.

FIG. 3 is a sectional view showing an example of a developing device of a conventional image recording apparatus.

[Explanation of symbols]

12 Agitator 12a　　　vine-like part 18 Rotation axis 20 Drive gear 22 Leaf spring (elastic member)

Claims (2)

[Claims] Claims: 1. A developing device for an image recording apparatus comprising a rotating shaft that rotates within a toner hopper, and an agitator attached to the rotating shaft to agitate the toner within the toner hopper, wherein the agitator is freely rotatable about the rotating shaft. 1. A developing device for an image recording apparatus, characterized in that an elastic member is fixed to the rotating shaft for positioning the agitator with respect to the rotating shaft. 2. The agitator according to claim 1, wherein the agitator is made of a wire spring material, both ends of the wire spring material are processed into a tendril shape, and the tendril-like portions are entwined around the rotating shaft. A developing device for an image recording device.