JPH0322622B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device for a driven unit that is detachably attached to a main body of an apparatus such as an electrophotographic copying machine.

As is well known, in devices such as electrophotographic copying machines that use multiple driven units, for convenience of assembly and maintenance management of these driven units, it is not possible to attach or remove the driven units from the main body of the device. In many cases, the structure is such that the driven side shaft joint of the driven unit can automatically engage the driving side shaft joint provided on the device main body in this assembled state.
That is, FIG. 1 shows a developing unit A of an electrophotographic copying machine, which is one of such structures, and this developing unit A slides along a rail plate 2 installed on a body frame 1 of the apparatus main body. As a result, it can be detachably attached to the main body of the device. On the other hand, the fuselage frame 1 is provided with a mounting plate 4 held by a spacer 3, and between this mounting plate 4 and the fuselage frame 1 is a driving means, that is, a sprocket wheel 7 supported by bearing metals 5 and 6. The rotational force from the drive chain 8 is transmitted to the sprocket wheel 7. The sprocket wheel 7 has a pawl 9a protruding toward the developing unit A.
A drive-side shaft joint 9 having a shaft joint 9b is integrated, and when the developing unit A is completely attached to the rail plate 2, the rotary sleeve 1 is attached to this drive-side shaft joint 9.
0 driven side shaft joints 10 can meet.

Therefore, with such a structure, although the drive system can be automatically engaged and disengaged by attaching and detaching the developing unit A to the apparatus main body, the accuracy of positioning between the developing unit A and the apparatus fixing part is limited. It is difficult for the center line a of the sprocket wheel 7 and the center line b of the rotating sleeve 10 to be perfectly concentric with each other due to the dimensional accuracy of each part of the device, and an eccentric amount P occurs between the two. For this reason, drive side shaft joint 1
The rotating sleeve 10, which is rotationally driven by the rotary shaft 10, has angular velocity fluctuations during rotation, which may cause density unevenness in the developed image, or cause the entire developing device to oscillate, causing the photoreceptor drum to The interval between developing sleeves changes slightly.

In view of the problems with driving conventional driven units as described above, the present invention automatically engages and disconnects the drive system simply by attaching and detaching the driven unit to the main body of the device. The present invention proposes a drive device with a structure that does not involve angular velocity fluctuations in the rotational movement of the unit. That is, in the present invention, a driven unit having a driven side shaft joint at the tip of a driven shaft is detachably attached to the device fixing part, and a driving side shaft joint for rotationally driving the driven shaft is attached to the device fixing part. In a drive device for a driven unit rotatably supported by a drive unit, a large-diameter mounting hole is bored in the device fixing portion to support a drive sprocket wheel with the drive-side shaft joint integrated therein in a sealed state; A driving device for a driven unit, wherein a center hole is formed in the center of the driving side shaft joint facing the driven side shaft joint, and a guide rod that can be inserted into the central hole projects from an end face of the driven side shaft joint. be.

Embodiments of the present invention will now be described in detail with reference to FIGS. 2 and 3.

The illustrated embodiment is an example in which the present invention is applied to a developing unit A of an electrophotographic copying machine, and this developing unit A includes a storage box 11 containing a developer.
This storage box 11 is slidably attached to the main body of the apparatus along a rail plate 13 installed on the body frame 12. The housing box 11 includes a rotary sleeve 15 containing a plurality of permanent magnets 14 and a wing 1.
6 are housed therein, and these rotating sleeves 15 and trailing blades 16 are pivotally supported with respect to the housing box 11 by bearings 17 and 18 shown in FIG. The sleeve shaft 19 and the companion shaft 20 led out from the storage box 11 are connected to a spur shaft 2 which is meshed with each other.
1 and 22 are fixed, and the rotating sleeve 15 and thus the trailing blade 16 are rotated synchronously.

On the other hand, the fuselage frame 12 is provided with a mounting plate 24 held by a spacer 23, and between this mounting plate 24 and the fuselage frame 12, a pair of bearing metals 25 are provided.
A drive means or sprocket wheel 26 is located which can rotate about A and 25B. The bearing metals 25A and 25B are located in large diameter mounting holes 27 and 28 bored in the mounting plate 24 and the fuselage frame 12, and therefore the sprocket wheel 26 driven by the drive chain 29 is It is placed in a floating state in the radial direction of the mounting holes 27 and 28. The sprocket wheel 26 has pawls 30a and 30b protruding toward the sleeve shaft 19.
A drive-side shaft joint 30 having a sprocket wheel 26 is integrated into the drive-side shaft joint 30.
A central hole 31 concentric with is drilled.

The end of the sleeve shaft 19 is provided with the pawl 30.
A driven side shaft joint 32 having a radial protrusion 32a that can be engaged with the shafts 30a and 30b is integrated. Also,
A guide rod 33 that is concentric with the rotation center of the rotary sleeve 15 is protruded from the end surface of the driven shaft joint 32 . A guide rod 3 having the same outer diameter as the center hole 31
The tip end 33a of No. 3 has a tapered surface so that it can be inserted into the center hole 31 reliably.

Since the apparatus of the embodiment has the above-described structure, when the developing unit A is slidably attached to the body frame 12, the tip end 33a of the guide rod 33 engages with the center hole 31, so that the developing unit A As the sprocket wheel 26 is pushed forward, the center of rotation of the sprocket wheel 26 and the drive side shaft joint 30, which are in a floating state, is specified. That is, at this specified rotation center position, the center lines of the sprocket wheel 26 and the drive side shaft joint 30 are concentric with the rotation center of the rotating sleeve 15. Therefore, as long as there is no speed variation in the sprocket wheel 26, no angular swing of the rotary sleeve 15 will occur, so that the developed image will not have any adverse effects such as density unevenness due to the swing. Further, the use of the unit feeding mechanism according to the present invention is particularly useful in preventing uneven development, for example, in a method in which the rotating sleeve 15 of the developing device and the photosensitive drum surface are extremely close to each other.

Although the developing unit is illustrated in the above embodiment, it is obvious that the present invention can be applied to other driven units that are sensitive to angular velocity fluctuations.

As a result, according to the present invention, it is possible to obtain an effective drive device in which not only the drive system is automatically engaged and detached by attaching and detaching the driven unit to and from the device main body, but also does not cause angular velocity fluctuations when transmitting rotational force.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a drive section of a conventional driven unit, FIG. 2 is a sectional view of a developing unit according to the present invention, and FIG. 3 is a sectional view taken along the line -- in FIG. A...Developing unit, 11...Storage box, 12...
. . . Airframe frame, 15 . . . Wing, 26 . . . Sprocket wheel (driving means), 30 .

Claims (1)

[Claims] 1. A driven unit having a driven-side shaft joint at the tip of the driven shaft is removably attached to the device fixing part, and a driving-side shaft joint that rotationally drives the driven shaft is rotatably supported on the device fixing part. In a drive device for a driven unit, a large-diameter mounting hole is bored in the device fixing part to support a driving sprocket wheel with the driving side shaft joint integrated therein in a floating state, and the driving sprocket wheel with which the driving side shaft joint is integrated is supported in a floating state. A drive device for a driven unit, characterized in that a center hole is formed in the center of the facing driving side shaft joint, and a guide rod that can be inserted into the concentric hole projects from an end face of the driven side shaft joint.