JPH04107343A - Drive transmission member - Google Patents

Abstract

PURPOSE:To improve a strength of coupling with a driven member and to provide an increased life for a drive transmission member by integrally molding a coupling part, composing the drive transmission member, and a driven transmission part by using different materials. CONSTITUTION:A drum gear 18 being a drive transmission member is mounted in an opening part A of a sensitizing drum 3 and the drum gear 18 is located rotatably around a support axle 20 supported to a frame body 19. The drum gear 18 is provided with a coupling part 18a engaged with the sensitized drum 3 and a driven transmission gear 18b being a driven transmission member to which a drive force is transmitted from a drive source. The driven transmission gear 18b is engaged with a drum driving gear 21. The coupling part 18a and the driven transmission gear part 18b of the drum gear 18 are integrally molded together by using different materials. This constitution improves a strength of coupling with the driven member and provides an increased life for the drive transmission gear 18b.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is applicable to an image forming apparatus such as a copying machine, a printer, a laser beam printer, a facsimile, etc., which is fitted into an opening of a driven member such as a photosensitive drum or a developing sleeve. The present invention relates to a drive transmission member that is attached.

<Prior Art> Conventionally, various mechanical parts have been used in image forming apparatuses such as copying machines and printers, among which a drive transmission member fitted into an opening of a cylindrical member has been used. There are many things that are covered.

For example, the description will be made with reference to a drum gear constituting an image forming means of a laser beam printer shown in FIG.

The photosensitive drum 50 is constructed by coating a photosensitive layer on the surface of an aluminum cylinder. A drum gear 51 is fitted into the opening A of the photosensitive drum 50. The drum gear 51 is rotatably supported by a frame 52 around a support shaft 53 integrally with the photosensitive drum 50 . A drum drive gear 54 that transmits driving force from a drive source meshes with the drum gear 51.

The drum gear 51 is fitted and bonded to the inner peripheral surface of the opening of the photosensitive drum 50 and transmits the driving force from the drum drive gear 54 to the photosensitive drum 50.

Therefore, the material for the drum gear 51 is preferably a material that has good adhesive properties and excellent sliding properties, and conventionally, for example, fluorine-containing polycarbonate or the like has been used.

<Problems to be Solved by the Invention> However, in the above configuration, there is a problem that the material of the drum gear 51 has a low mechanical strength, particularly fatigue strength.

Therefore, if the material of the drum gear 51 is made of polyacetal, the fatigue strength of the gear will not be a problem, but it will be difficult to adhere to the photosensitive drum 50, and screws etc. will be required to join the photosensitive drum 50, resulting in a complicated structure. There is a risk that it will become

Furthermore, when the drum gear 51 is press-fitted into the opening A of the photosensitive drum 50, the coefficient of thermal expansion is greatly different between the aluminum of the photosensitive drum 50 and the polyacetal of the drum gear 51, so polyacetal shrinks more than aluminum in a low-temperature environment, causing the drum flange to shrink. There was a risk that it would come off.

If the material of the drum gear 51 is made of polycarbonate containing glass fiber, there will be no problem with the strength of the gear and the adhesion with the photosensitive drum 50, but it will increase the cost and wear out the tooth surface of the drum drive gear 54. Easy to do.

Furthermore, in order to obtain reliability by adhering the drum gear 51 to the photosensitive drum 50, it is necessary to control the temperature and humidity during adhesion, drying or curing time is required, and it is necessary to prevent dirt, oil, etc. from adhering to the adhesion surface. Therefore, there was a risk that the device would become larger. Furthermore, adhesives are vulnerable to impact and heat shock, and may be subject to restrictions on logistics and storage conditions.

An object of the present invention is to solve the problems of the prior art described above and to provide a drive transmission member in which a connecting portion and a driven transmission portion are integrally molded from different materials.

<Means for Solving the Problems> Typical means for solving the problems of the above-mentioned prior art and applied to the embodiments described below include a connection part that is press-fitted or welded into an opening of a driven member, and a drive source. and a driven transmission part to which a driving force is transmitted, and the connecting part and the driven transmission part are integrally molded from different materials.

<Operation> According to the above means, by integrally molding the connecting part that is press-fitted or welded into the opening of the driven member and the driven transmission part to which driving force is transmitted from the drive source from different materials,
The life of the drive transmission member can be improved by increasing the bonding strength with the driven member.

<Example> Hereinafter, an example of a drive transmission member to which the present invention is applied will be described with reference to the drawings. In this embodiment, a laser beam printer is used as an image forming apparatus, and a drum gear that constitutes a photoreceptor will be described.

Fig. 1 is an explanatory cross-sectional view of the photoreceptor, and Fig. 2 is the N of the above cross-sectional view.
-N cross-sectional view, Figure 3 is a grab showing the fatigue strength of each material,
FIG. 4 is an explanatory cross-sectional view showing a schematic configuration of a laser beam printer equipped with the above-mentioned photoreceptor.

First, the schematic structure of the laser beam printer will be explained with reference to FIG.

2 is a scanner unit that irradiates and scans a laser beam according to recorded information; 2 is a process cartridge; 3 is a photosensitive drum that is an image carrier; 4 is a primary charger that is a corona discharger; Developing device containing toner5. cleaner 6
It has built-in recording means such as

Further, the goo light emitted from the scanner unit 1 is irradiated onto the photosensitive drum 3 in the process cartridge 2 via the reflection mirror 7.

The photosensitive drum 3 is charged in advance by a primary charger 4, and is irradiated with laser light to form an electrostatic latent image, and then a toner image is formed by a developer 5 and visualized.

On the other hand, the sheet materials 10 fed from the paper feed cassette 8 by the feed roller 9 are separated one by one by a separation pad 11 provided opposite to the feed roller 9. The separated sheet material 10 is guided by guide plates 12a and 12b provided above and below, and is conveyed between a pair of registration rollers 13a and 13b, which are temporarily stopped, to correct the skew.

Next, the sheet material 10 is attached to a pair of registration rollers 13a.

13b, the toner image is intermittently conveyed to the transfer section in synchronization with the leading edge of the toner image formed on the photosensitive drum 3.

14 is a transfer charger for transferring the toner image formed on the photosensitive drum 3 onto the sheet material 10.

The transfer charger 14 charges the back side of the sheet material 10 with a polarity opposite to that of the toner, and the toner image is sequentially transferred from the photosensitive drum 3 onto the sheet material 10.

Sheet material 1 to which an image has been transferred by the transfer charger 14
0 is separated from the photosensitive drum 3 and conveyed to the downstream side. The toner remaining on the photosensitive drum 3 is removed by a cleaner 6.
is removed and prepared for the next recording.

Further, the unfixed transferred image on the separated and conveyed sheet material 10 is permanently fixed in a fixing device 15, and then is discharged onto a discharge tray 17 outside the apparatus by a pair of discharge rollers 16a and 16b.

Next, a drum gear applied to the photosensitive drum 3 will be explained with reference to FIG.

First, in FIG. 1, the photosensitive drum 3 is an image carrier on which an image is formed, and has a photosensitive layer coated on the surface of an aluminum cylinder.

A drum gear 18, which is a drive transmission member, is attached to the opening A of the photosensitive drum 3. This drum gear 18 is rotatably attached around a support shaft 20 supported by a frame 19.

The drum gear I8 has a connecting portion 18a that fits with the photosensitive drum 3, and a driven transmission gear 18b that is a driven transmission portion to which driving force is transmitted from a drive source. , and the drum drive gear 21 are in mesh with each other.

Note that 22 is an intermediate gear that transmits driving force to the drum drive gear 21.

The connecting portion 18a and the driven transmission gear portion 18b of the drum gear 18 are formed by commonly used insert molding.
It is integrally molded from different materials.

That is, the connecting portion 18a is made of the same aluminum alloy as the photosensitive drum 3, and the driven transmission gear 18b is made of a strong material suitable for use as a gear, such as polysecure or nylon.

The drum gear 18 is attached by fitting the connecting portion 18a through the opening A of the photosensitive drum 3 and press-fitting it into the inner peripheral surface.

At this time, the photosensitive drum 3 functions as a support member for the drum gear 18, and since the connecting portion 18a and the photosensitive drum 3 are made of the same material, the photosensitive drum 3 can be used at high temperatures without being affected by differences in thermal expansion coefficients. Good bonding strength can be obtained even at low temperatures.

Further, FIG. 2 shows a cross section taken along arrow N-N in FIG. It is constructed to transmit sufficient force. Further, the teeth of the spline are undercut to prevent the driven transmission gear 18b of the drum gear 18 from contracting at low temperatures and creating a gap with the connecting portion 18a.

FIG. 3 is a graph showing the fatigue strength of various materials that can be used as materials for the drive transmission member.

In the above graph, the horizontal axis indicates the number of repeated uses, and the vertical axis indicates the magnitude of allowable bending stress.

According to the above graph, since the driven transmission gear 18b receives a lot of bending stress at its teeth, it is preferable to use a material with high fatigue strength such as polyacetal.

Further, in this embodiment, the same effect can be obtained even if the connecting portion 18a of the drum gear 18 is made of a material having a coefficient of thermal expansion comparable to that of the photosensitive drum 3, such as brass or phosphor bronze.

According to the above configuration, the connecting portion 1 constituting the drum gear 18
By integrally molding the driven transmission gear 8a and the driven transmission gear 18b from different optimal materials, the life of the drum gear 18 can be improved and the connection with the photosensitive drum 3 can be maintained well regardless of temperature dependence.

Although this embodiment has been described with reference to the case where it is applied to a laser beam printer as an image forming apparatus, the present invention is not limited to this and may be applied to other apparatuses such as copying machines and facsimile machines.

<Other Embodiments> Next, other embodiments of the drive transmission member described above will be described with reference to FIGS. 5 and 6.

Referring to FIG. 5, a case will be described in which this embodiment is applied to a developing sleeve gear that conveys developer using a drive transmission member as a driven member.

23 is a developing sleeve, which is configured in the shape of an aluminum cylinder. A developing sleeve gear 24 is attached to the opening A' of the developing sleeve 23, and a rotating magnet 26 is attached inside thereof so as to be rotatable about a rotating shaft 26a supported by a support member 25. The developing sleeve gear 24 includes a connecting portion 24a that is press-fitted into the developing sleeve 23, and a driven transmission gear 24b.

The connecting portion 24a is made of aluminum, and the driven transmission gear 24
b uses polyacecool, and these are integrated by insert molding.

Further, the driven transmission gear 24b meshes with a driven transmission gear 18b attached to the photosensitive drum 3, and is configured to rotate the developing sleeve 23 in synchronization with the photosensitive drum 3.

Next, FIG. 6 shows a case where the drum gear 27 is connected to the photosensitive drum 3 by ultrasonic welding.

The drum gear 27 is connected to the ultrasonic welding part 2 which is a connecting part.
7a and a driven transmission gear 27b which is a driven transmission part, the ultrasonic welding part 27a is made of the same aluminum alloy as the photosensitive drum 3, the driven transmission gear 27b is made of a material such as polyacetal, and an insert is used. The two are integrated by molding.

The drum gear 27 is fixed with a jig so that the centers of the drum gear 27 and the photosensitive drum 3 coincide with each other at the open end C of the photosensitive drum 3, and are ultrasonically bonded.

Since the drum gear 27 vibrates in the radial direction during the ultrasonic bonding process, the boss portion is formed with a small diameter so as to create a gap between it and the inner peripheral surface of the photosensitive drum 3.

According to the above configuration, in ultrasonic bonding, the drum gear 27 is bonded to the open end surface C of the photosensitive drum 3, so the boss portion of the drum gear 27 can be shortened, so that cost reduction can be achieved. .

Further, as in the embodiment described above, while maintaining the strength of the driven transmission gear 27b, the bonding force with the photosensitive drum 3 can be improved, and the life of the drum gear 27 can be extended.

The drive transmission member described above is not limited to the parts shown in each embodiment, but can be applied to various parts having a cylinder shape, such as a rotary drum of a printing machine, a conveyance roller, etc. It can also be applied to gears connected to.

<Effects of the Invention> As described above, the present invention improves the strength of the connection with the driven member by integrally molding the connecting portion and the driven portion that constitute the drive transmitting member from optimally different materials. Therefore, the life of the drive transmission member can be improved.

Furthermore, by forming the connecting portion with a material having the same or similar coefficient of thermal expansion as that of the driven member, the drive transmission member and the driven member can be connected regardless of temperature dependence. can improve sex.

[Brief explanation of the drawing]

Fig. 1 is an explanatory cross-sectional view of the photoreceptor, and Fig. 2 is the N of the above cross-sectional view.
-N cross-sectional view, Figure 3 is a grab showing the fatigue strength of each material,
FIG. 4 is an explanatory cross-sectional view showing a schematic configuration of a laser beam printer equipped with the above-mentioned photoreceptor, FIGS. 5 and 6 are explanatory views of the other side, and FIG. 7 is an explanatory view of a conventional example. 1 is a scanner unit, 2 is a process cartridge, 3
1 is a photosensitive drum, 4 is a primary charger, 5 is a current detector, 6 is a cleaner, 7 is a return mirror, 8 is a paper feed cassette, 9 is a feed roller, 10 is a sheet material, 11 is a separation band, 1
2a and L2b are guide plates, 13a and 13b are a pair of registration rollers, 14 is a transfer charger, 15 is a fixing device, 16a,
16b is a pair of discharge rollers, 17 is a discharge tray, 18.2
7 is a drum gear, 18a, 24a are connecting parts, 18b, 2
4b and 27b are driven transmission gears, 19 is a frame, 20 is a support shaft, 21 is a drum drive gear, 22 is an intermediate gear, 23 is a developing sleeve, 24 is a developing sleeve gear, 25 is a support member, and 26 is a rotating magnet. , 26a is a rotating shaft, and 27a is an ultrasonic welding part.

Claims (7)

[Claims] (1) It has a connecting part that is press-fitted or welded into the opening of the driven member, and a driven transmission part that transmits the driving force from the drive source, and the connecting part and the driven transmission part are integrally molded from different materials. A drive transmission member characterized by: (2) The drive transmission member according to claim 1, wherein the connecting portion is made of a material having the same or similar coefficient of thermal expansion as that of the driven member. (3) The drive transmission member according to claim (1), wherein the driven transmission portion is made of a material with high mechanical strength. (4) The drive transmission member according to claim (1), wherein a portion adjacent to the connecting portion and the drive transmission portion is formed into a spline shape. (5) The drive transmission member according to claim (1), wherein the driven member is a photoreceptor serving as an image carrier. (6) The drive transmission member according to claim (1), wherein the driven member is a developing sleeve that conveys developer. (7) The drive transmission member according to any one of claims (1) to (6), wherein the drive transmission member is a gear.