JP2003066663A - Roller for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an improved roller for an image forming device in which a helical gear is easily and highly accurately assembled into a roller main body. SOLUTION: This roller consists of the roller main body and transmission members attached at both ends of the roller main body, and the roller main body is provided with a first hollow cylindrical part, a second hollow cylindrical part whose diameter is larger than that of the first hollow cylindrical part and that is coaxially arranged with the first hollow cylindrical part and a rib connecting hollow cylindrical parts and also extended in the extending direction of the hollow cylindrical part, and the transmission member is provided with a shaft part force-fitted into the first hollow cylindrical part and the helical gear attached to the shaft part. The transmission member is provided with a fitting projected part inserted into a space between the first hollow cylindrical part and the second hollow cylindrical part and also having a fitting groove in which the helical gear is positioned in a rotating direction by the rib.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller of an image forming apparatus, and more specifically, it transmits a helical gear like a developing roller in a developing device of an image forming apparatus such as an electronic copying machine or a printer. The present invention relates to an improvement of a roller used as a member.

[0002]

2. Description of the Related Art Conventionally, a developing roller in an image forming apparatus of this type, for example, a developing device of a copying machine, includes a roller body 1 and a transmission member 5, as shown in FIGS.

The roller body 1 is made of an extruded aluminum product and has two hollow cylindrical portions 2 and 3 and a rib 4. The hollow cylindrical portion 2 has a smaller diameter than the hollow cylindrical portion 3 and is arranged coaxially with the hollow cylindrical portion 3. Rib 4
Are three and are arranged at equal intervals with respect to the central axis of the roller body 1. Each of the ribs 4 is a plate-like member extending along the extending direction of the hollow cylindrical portion, and both side edges in the longitudinal direction are connected to the hollow cylindrical portions 2 and 3.

The transmission member 5 includes a shaft portion 6 and a helical gear 7. The shaft portion 6 has one end press-fitted into the hollow cylindrical portion 2. The helical gear 7 is provided with a D-shaped shaft hole 8, and an end portion of the shaft portion 6 extending from the roller body 1 to the outside is formed in a D-shaped cross section. The helical gear 7 is pressed into the shaft portion 6 with the D-cut surface 9 ′ of the shaft hole 8 aligned with the D-cut surface 9 ′ of the shaft portion 6.

[0005]

When the developing roller is incorporated in a copying machine, the helical gear 7 meshes with the helical gear of the image carrier on which an electrostatic image is formed. Assembling No. 7 requires high dimensional accuracy. If the D-cut surfaces 9 of the transmission members 5 at both ends of the roller body 1 have an angular deviation θ, the teeth of the helical gear 7 and the teeth of the helical gear of the image carrier are not firmly engaged with each other, resulting in a final image. Image unevenness occurs.

In order to prevent this, the teeth of the helical gear 7 are created with reference to the D-cut surface 9 on the shaft portion 6, and the shaft portions 6 of both transmission members 5 have an angular deviation θ of the D-cut surface 9 of, for example, an angle. It is press-fitted into the hollow cylindrical portion 2 of the roller body 1 so as to be 30 'or less.

However, in order to press-fit the shaft portion 6 of the transmission member 5 into the roller main body 1 with such high dimensional accuracy, the press-fitting accuracy must be strictly controlled, which requires considerable labor and cost.

It is an object of the present invention to provide an improved roller for an image forming apparatus which allows the transmission member to be assembled to the roller main body more easily and with high accuracy.

[0009]

In order to achieve the above object, the roller of the image forming apparatus of the present invention comprises a roller main body and transmission members attached to both ends of the roller main body.
The roller body has a first hollow cylindrical portion, a second hollow cylindrical portion having a diameter larger than that of the first hollow cylindrical portion, and coaxially arranged with the first hollow cylindrical portion, and these hollow cylinders. And a rib extending along the extending direction of the hollow cylindrical portion, wherein the transmission member includes a shaft portion press-fitted into the first hollow cylindrical portion and a helical gear attached to the shaft portion. The transmission member has a fitting protrusion that is inserted into the space between the first hollow cylindrical portion and the second hollow cylindrical portion and that has a fitting groove that positions the helical gear with respect to the rotational direction by the rib. It is provided in.

In order to achieve the above object, in the roller of the image forming apparatus of the present invention, in the above roller, the helical gear is integrally formed with the shaft portion.

To achieve the above object, in the roller of the image forming apparatus of the present invention, in the above-mentioned roller, the fitting protrusion is formed integrally with the helical gear.

In order to achieve the above object, the roller of the image forming apparatus of the present invention is the above-mentioned roller, wherein the fitting protrusion is in the form of a ring.

In order to achieve the above object, the rollers of the image forming apparatus of the present invention are the same number as the above-mentioned rollers, with the fitting grooves corresponding to the ribs.

[0014]

The transmission member is mounted on the roller body by pressing the shaft portion of the transmission member into the first hollow cylindrical portion of the roller body. At this time, the fitting protrusion is inserted between the hollow cylindrical portions, and at the same time, the fitting groove of the fitting protrusion is fitted into the rib, and the position of the transmission member in the rotational direction is determined by the rib. Therefore, the helical gear can be attached to the roller body with high accuracy by simply press-fitting the transmission member into the roller body. Further, even when this roller is incorporated in the image forming apparatus, the rib receives a load applied to the helical gear, so that the roller can withstand a high torque.

In the roller of the image forming apparatus of the present invention,
If the helical gear is formed integrally with the shaft portion, there is no play between the helical gear and the shaft portion, so the helical gear is mounted on the roll body with high accuracy, and a roller with which a more stable image quality can be obtained. Can be Further, it is possible to obtain a roller with stable quality, since it is not necessary to process the helical gear to the shaft portion and the machining is required for the attachment.

There are a number of fitting grooves corresponding to the ribs of the roller body, and if each fitting groove is fitted in each rib,
Since the torque is received by all the ribs, the roller can withstand higher torque.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a roller of an image forming apparatus of the present invention will be described below with reference to FIGS.

This roller is a developing roller incorporated in a developing device of an electronic copying machine, for example, and includes a roller body 11 and a transmission member 21 as shown in FIG.

As shown in FIGS. 2 to 4, the roller body 11 is provided with cylindrical portions 12 and 13 and three ribs 14. The cylindrical portions 12 and 13 are in the form of hollow cylinders whose both ends are open. The hollow cylindrical portion 12 has a smaller diameter than the hollow cylindrical portion 13, and is arranged inside the hollow cylindrical portion 13 coaxially with the hollow cylindrical portion 13. The rib 14 has a flat plate shape. The ribs 14 are arranged between the hollow cylindrical portions 12 and 13 along the hollow cylindrical portions 12 and 13 and at equal angular intervals with respect to the central axis portion of the roller body 11. Both side edges of the rib 14 in the longitudinal direction are connected to the outer peripheral surface of the hollow cylindrical portion 12 and the inner peripheral surface of the hollow cylindrical portion 13.

The roller body 11 is made of, for example, an aluminum extrusion molding. Although not shown, a functional film for forming an image is provided on the outer peripheral surface of the hollow cylindrical portion 12. The functional film is formed by, for example, extruding the roller body 11, then cutting the outer peripheral surface of the roller body 11 with reference to both ends of the roller body 11, and then spray-coating a conductive resin on the cut surface. Has been formed.

The transmission member 21 includes a shaft portion 22 and a helical gear 23.
And a fitting protrusion 24. The shaft portion 22 has a solid cylindrical shape and has an outer diameter of the roller body 11
Is approximately equal to or slightly larger than the inner diameter of the hollow cylindrical portion 12. The helical gear 23 is formed integrally with the shaft portion 22. The mating protrusion 24 is substantially ring-shaped. The inner diameter of the fitting protrusion 24 is equal to that of the roller body 1.
1 is equal to or slightly smaller than the outer diameter of the hollow cylindrical portion 12, and the outer diameter is equal to or slightly larger than the inner diameter of the hollow cylindrical portion 13 of the roller body 11. The fitting protrusion 24 is coaxial with the shaft 22 and has a helical gear 23.
Of the helical gear 23 and is integrally formed with the helical gear 23. Three fitting grooves 25 are provided from the outer peripheral surface of the fitting protrusion 24 toward the inner peripheral surface. These fitting grooves 25 are arranged at equal angular intervals with respect to the central axis of the shaft portion 22. The width of the fitting groove 25 is the same as or slightly smaller than the thickness of the rib 14 of the roller body 11. The transmission member itself is made of a sintered alloy, and the shaft portion 22, the fitting protrusion portion 24, and the helical gear 23 are integrally formed.

There are two transmission members 21 as shown in FIG. 1, and each of them is attached to both ends of the roller body 11.

The shaft 22 is attached to the hollow cylindrical portion 13 of the roller body 11, the fitting protrusion 24 is attached to the hollow cylindrical portion 12,
13 in the space between the ribs and each of the fitting grooves 25.
It is made by press-fitting into 4 respectively. When press-fitted, the transmission member 21 is joined to the roller body 11 by these press-fits, and the helical gear 23 has the rib 14 and the fitting groove 2.
Positioning in the rotational direction is made by fitting with 5.

The developing roller according to the present invention is thus
The fitting of the rib 14 and the fitting groove 25 positions the helical gear 23 in the rotational direction, so that the helical gears 23 at both ends of the roller body 11 can be assembled to the roller body 11 in the same state. Therefore, the assembly of the transmission member 21 with respect to the roller body 11 does not require accuracy control, and the assembly can be performed at low cost.

Although not shown in the drawing, the developing roller according to the present invention is arranged in the main body of the copying machine by bringing it into contact with an image carrier on which an electrostatic image is formed and a toner supply roller, which is not shown in the drawing. The helical gears 23 of FIG. 2 are engaged with the helical gears at both ends of the image carrier, and the end portions 2 of the shaft portion 22 are
Each of the 6 is held by a bearing in the main body of the copying machine.

At this time, since the helical gears 23 on both ends of the developing roller are assembled to the roller body 11 in the same state, the teeth of the helical gear 23 surely mesh with the teeth of the helical gear of the image carrier. Therefore, when copying is performed, it is possible to obtain a final image without unevenness in the portions related to both ends of the developing roller. The driving torque is received not only by the press-fitting portion between the shaft portion 22 of the transmission member 21 and the hollow cylindrical portion 13 of the roller body 11 but also by the three ribs 14, so that the developing roller can withstand a high torque, resulting in a failure. A low-reliability copying machine can be obtained.

In the embodiment described above, the helical gear 23 is formed integrally with the shaft portion 22, but the helical gear 23 having a D-shaped axial hole is manufactured separately from the transmission member 21, and this is transmitted. It may be pressed into the D-cut surface of the member 21. Since the transmission member 21 and the helical gears are formed by molding or machining to ensure the required accuracy, the installation can be performed with high accuracy in this case as well.

Although the fitting protrusion 24 is integral with the helical gear 23, it may be integral with the shaft 22 depending on the structure of the developing roller.

[0029]

As described above, in the roller of the image forming apparatus of the present invention, when the shaft portion of the transmission member is press-fitted into the first hollow cylindrical portion of the roller body, the fitting groove of the fitting protruding portion is formed into the roller. There is an effect that it fits into the rib of the main body, and the rib determines the position of the transmission member in the rotational direction, that is, the existing rib in the roll main body is used to assemble the transmission member to the roller main body.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of rollers of an image forming apparatus of the present invention.

FIG. 2 is a vertical sectional view taken along the line AA of FIG.

3 is a cross-sectional view taken along the line BB of FIG.

FIG. 4 is an exploded perspective view of a transmission member and a partially cut roller body of the roller shown in FIG.

FIG. 5 is an explanatory diagram showing a configuration of rollers of a conventional image forming apparatus.

6 is a cross-sectional view taken along the line CC of FIG.

[Explanation of symbols]

11 ... roller body 12 ... First hollow cylindrical portion 13 ... Second hollow cylindrical portion 14 ... Ribs 21 ... Transmission member 22 ... Shaft, 23 ... helical gear 24 ... Fitting protrusion 25 ... Fitting groove

Claims (5)

[Claims] 1. A roller main body and a transmission member attached to both ends of the roller main body, wherein the roller main body has a first hollow cylindrical portion and a diameter larger than the diameter of the first hollow cylindrical portion. A second hollow cylindrical portion coaxially arranged with the one hollow cylindrical portion, and a rib connecting the hollow cylindrical portions and extending along the extending direction of the hollow cylindrical portion, wherein the transmission member has the first hollow portion. In a roller of an image forming apparatus including a shaft portion press-fitted into a cylindrical portion and a helical gear attached to the shaft portion, the roller is inserted into a space between the first hollow cylindrical portion and the second hollow cylindrical portion. And a fitting projection having a fitting groove for positioning the helical gear with respect to the rotational direction by the rib, is provided on the transmission member. 2. The roller of the image forming apparatus according to claim 1, wherein the helical gear is formed integrally with the shaft portion. 3. The roller of the image forming apparatus according to claim 2, wherein the fitting protrusion is formed integrally with the helical gear. 4. The roller of the image forming apparatus according to claim 3, wherein the fitting protrusion is in the form of a ring. 5. The number of fitting grooves corresponding to the number of ribs is 4.
The roller of the image forming apparatus described in 1.