JPH04298779A - Holding device for cylindrical drum - Google Patents

Abstract

PURPOSE:To hold a cylindrical drum with high accuracy while reducing the quantity of shape variation which is caused on both end surfaces of the cylindrical drum at the time of clamping as compared with a conventional value. CONSTITUTION:Tapered parts 1a and 1a are provided at the outer periphery of the cylindrical drum 1 at both ends, a couple of coupling flanges 2 and 2 which have tapered parts 2a and 2b, which engage the tapered parts 1a and 1b, at the inner periphery of a holding part 7 are arranged, and clamping means 3a and 4 are provided to a coupling shaft 3 arranged penetrating the centers of both the coupling flanges 2 and 2 to clamp the cylindrical drum 1 between both the coupling flanges 2 and 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for highly accurately holding cylindrical drums such as photosensitive drums and developing sleeves used in various types of office equipment.

0002

2. Description of the Related Art Conventionally, as a holding device for a cylindrical drum, an inner diameter chuck type device as shown in FIG. 2 has been used.

A conventional method for holding a cylindrical drum will be explained below. In FIG. 2, 5 is a cylindrical drum, and has tapered portions 5a on the inner periphery of both ends thereof. Reference numerals 6 and 6 designate connection flanges, which have a tapered portion 6a at the same angle as the tapered portion 5a of the cylindrical drum 5, or at an angle before and after that, and are tapered fitted at each end of the cylindrical drum 5. be. 3 is a connecting shaft, and 4 is a fastening nut that is screwed into the threaded portion 3a of the connecting shaft 3. The cylindrical drum 5 and the pair of connecting flanges 6, 6 are connected by fastening the fastening nut 4 with their tapered portions 5a, 6a tapered-fitted to each other. and taper part 5
Due to the frictional forces at a and 6a, the cylindrical drum 5
is maintained.

Regarding the cylindrical drum holding device constructed as described above, stress to which the cylindrical drum 5 is subjected will be explained below. First, F' is the connecting flange 6, 6
The stress due to the fastening of the fastening nut 4 transmitted through F'
x is the axial component of F', and F'y is the radial component of F'.

[0005]

However, in the conventional configuration described above, the radial component force F'y is
Because it acts to widen both ends of the drum and causes a change in shape, it is possible to use a high-precision drum (roundness of 10 μm or less, straightness of
It is difficult to satisfy assembly accuracy of 0 μm or less and cylindricity of 10 μm or less. For this reason, when the photosensitive drum is held, there is a problem in that image characteristics such as density unevenness are adversely affected.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a cylindrical drum holding device that minimizes the amount of change in shape of both ends of the cylindrical drum after fastening.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a cylindrical drum having tapered parts on the outer periphery of both ends thereof, and a holding part with a tapered part fitted on the inner periphery of the holding part. A pair of connecting flanges are arranged, and a tightening means is provided on a connecting shaft passing through the center of both connecting flanges, and a cylindrical drum is held in a sandwiched state between both connecting flanges. do.

[0008]

[Function] According to the present invention, the cylindrical drum is held by an outer diameter chuck method, and the rotation radius of the tapered fitting portion is made larger than that of the conventional inner diameter chuck method, and the taper fitting portion makes contact with each other. The area can be increased. Therefore, the frictional force per unit area required to hold the connecting shaft in the axial direction, radial direction, and rotational direction in the tapered portion is reduced. Therefore, the amount of change in the shape of both ends of the cylindrical drum caused by fastening the tightening means can be reduced, and the cylindrical drum can be held with high precision.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a cylindrical drum, and tapered portions 1a, 1a are provided on the outer periphery of both ends thereof. Reference numerals 2 and 2 designate a pair of connecting flanges, each of which has a tapered portion 2a on the inner periphery of the holding portion 7 at the same angle as the tapered portion 1a, or at an angle before or after the tapered portion 1a. 3 is a connecting shaft passing through the center of both connecting flanges 2, 2, and 4 is a fastening nut screwed into the threaded portion 3a of the connecting shaft 3. Cylindrical drum 1
and a pair of connecting flanges 2, 2 have mutually tapered portions 1a, 2.
They are joined together by fastening the fastening nut 4 in a state where the parts a are tapered fitted. The cylindrical drum 1 is held in three directions of the axial direction, the radial direction, and the rotational direction of the connecting shaft 3 by the frictional force in the tapered portions 1a and 2a.

Regarding the high-precision holding device for a cylindrical drum constructed as described above, stress to which the cylindrical drum 1 is subjected will be explained below. First, F is the connecting flange 2
, 2 due to the tightening of the tightening nut 4,
Fx is the axial component of F, and Fy is the radial component of F. Here, assuming that the inner and outer diameters and taper angle of the cylindrical drum are the same as those of the conventional example shown in FIG. 2, F will be smaller than F' and Fy will also be smaller than F'y. Therefore,
The amount of shape change occurring at both ends of the cylindrical drum 1 is smaller in the case of the present invention.

[0012] In the above embodiment, the tightening means is constituted by the threaded portion 3a of the connecting shaft 3 and the fastening nut 4 screwed onto the threaded portion 3a, but the present invention is not limited thereto.

[0013]

As described above, the present invention can reduce the amount of change in shape that occurs on both end faces of a cylindrical drum when fastened, compared to the conventional method, and can therefore improve the accuracy of the cylindrical drum. Retention can be achieved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a cylindrical drum holding device in an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional cylindrical drum holding device.

[Explanation of symbols]

1 Cylindrical drum 1a Taper part 2 Connecting flange 2a Taper part 3 Connecting shaft 3a Threaded part 4 Fastening nut 7 Holding part

Claims (1)

[Claims] Claim 1: A cylindrical drum is provided with tapered parts on the outer periphery of both ends, and a pair of connecting flanges each having a tapered part on the inner periphery of the holding part that taper-fits to each tapered part is provided, and the center of both connecting flanges is 1. A holding device for a cylindrical drum, characterized in that a cylindrical drum is held in a sandwiched state between both connecting flanges by providing a tightening means on a connecting shaft arranged to pass through the cylindrical drum.