JP2017155799A - Helical gear, driving device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent axial wearing of a resin helical gear in a drive train using the resin helical gear and E-ring for holding it.SOLUTION: A helical gear 7 has a protrusion shape part 9 acting as a hook part at a part of a gear end surface 8. The protrusion shape part 9 has a shape to be coincided with a clearance shape of an E-ring 4 and the protrusion part 9 is mounted to occupy the clearance of the E-ring 4 when assembled. Assembling to cause the protrusion part 9 to occupy the clearance of the E-rung 4 provides the E-ring 4 that is also rotated simultaneously by the protrusion shape part 9 upon rotation of a helical gear 2b. With this arrangement as above, even if the helical gear 2b receives a thrust force at the time of rotation to be contacted with the E-ring 4, no sliding occurs between an edge part of the E-ring 4 and the helical gear 2b and no cutting is generated.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a helical gear, a drive device including the same, and an image forming apparatus.

  In recent image forming apparatuses such as copiers, printers, facsimiles, and multi-function machines, resin gears are often used for the driving device in order to reduce weight and cost. In addition, many resin gears are arranged in a limited space in order to transmit the target rotation speed, torque, and the like. There are also various ways to hold the gear. Furthermore, a configuration using a helical gear in the unit drive train is already known for the purpose of high efficiency and low noise as a drive device. In particular, resin gears use helical gears and are often configured with durability and quietness taken into account.

  However, the helical gear generates a thrust force, and the gear moves in the axial direction during driving. In order to prevent this movement, an E-ring is often provided in the axial direction to prevent movement in the axial direction. However, the resin helical gear pressed against the E-ring by the thrust force has a problem that the edge of the E-ring and the shaft end face are rubbed and scraped.

  Patent Document 1 discloses a method in which a coil spring that absorbs axial thrust is interposed between a gear and a frame for the purpose of preventing vibrations during rotational driving from being transmitted to the machine frame. However, the problem that the resin gear shaft end face is scraped by sliding between the resin gear and the E-ring edge due to the axial thrust force cannot be solved.

  An object of the present invention is to prevent axial wear of a resin helical gear in a drive train using a plastic helical gear and an E-ring for holding it.

  The helical gear according to the present invention is characterized in that a convex end portion that can be mounted in the gap of the E-ring is provided at the shaft end that is the tip side in the installation direction of the E-ring for positioning.

  According to the present invention, since the helical gear and the E-ring in contact with the helical gear rotate synchronously due to the shape of the resin helical gear, the resin helical gear and the E-ring for holding it are used. In the conventional drive train, the axial wear of the resin helical gear can be prevented.

1 is a schematic configuration diagram illustrating a color printer as an example of an image forming apparatus that is an object of the present invention. It is a perspective view for demonstrating an example of the drive train used for the drive device. It is a perspective view for showing an example of the helical gear shown in FIG. It is a perspective view which shows the helical gear which concerns on embodiment of this invention. It is a top view which shows the gear train of the drive device using the helical gear which concerns on embodiment of this invention. It is a perspective view which shows a part of FIG. It is a top view which shows the gear train of the drive device using the helical gear which concerns on other embodiment of this invention.

  The present invention provides a helical gear made of resin and an E-ring in the axial direction thereof, and the drive train in which the helical gear receives a thrust force in the direction in which the E-ring is installed is as follows. Has characteristics. In short, the feature of the helical gear made of resin is that the helical gear and the E-ring in contact with the helical gear rotate synchronously.

The features of the present invention described above will be described in detail below with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating a color printer as an example of an image forming apparatus to which the present invention is to be implemented, and illustrates an image process unit, an exposure unit, and a transfer belt of the color printer. This printer includes process cartridges 1K, 1C, 1M, and 1Y corresponding to respective colors of black, cyan, magenta, and yellow (hereinafter referred to as K, C, M, and Y), and a photosensitive member 2K in the process cartridge. 2C, 2M, 2Y and developing devices 3K, 3C, 3M, 3Y. The four process cartridges 1Y, 1C, 1M, and 1K and the four developing devices 3K, 3C, 3M, and 3Y use different color toners (K, C, M, and Y toners) as image forming substances. Other than the above, the configuration is the same, and each is replaced when the lifetime is reached.

  The optical scanning device 40 optically scans the photosensitive members 2K, 2C, 2M, and 2Y in the process cartridges 1K, 1C, 1M, and 1Y with a laser beam emitted based on a control signal of the optical writing circuit. By this optical scanning, electrostatic latent images for K, C, M, and Y are formed on the photoreceptors 2K, 2C, 2M, and 2Y. The optical scanning device 40 irradiates a photoconductor through a plurality of optical lenses and mirrors while deflecting a laser beam emitted from a laser oscillator with a polygon mirror rotated by a motor.

  A transfer unit 60 is provided below the process cartridges 1K, 1C, 1M, and 1Y. The transfer unit 60 moves the intermediate transfer belt 50 as a transfer member endlessly while stretching. In addition to the intermediate transfer belt 50, the transfer unit 60 serving as a transfer unit includes a cleaning device 70 and the like. The intermediate transfer belt 50 sequentially passes through the primary transfer nips for K, C, M, and Y along with the endless movement thereof, and then K, C, and M on the photoreceptors 2K, 2C, 2M, and 2Y. , Y toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 50.

FIG. 2 is a perspective view for explaining an example of a drive train that has been used in the drive device.
A gear 1 (motor gear) that is a driving source and transmits a driving force, a step gear 2a that meshes with the gear 1, and an output gear 5 meshes with the step gear 2a. The shaft 3 has an E-ring 4 groove for positioning, and the axial direction of the step gear 2a is regulated by fitting the E-ring into the groove. When the gears 1, 2 a, and 5 are helical gears, a thrust force is generated in the axial direction of the step gear 2 a during driving, and the step gear 2 a is pressed against the E-ring 4 depending on the rotational direction. At this time, the end surface (shaft end surface) of the step gear 2a and the E ring 4 slide, and the end surface of the step gear 2a may be scraped by the corner of the E ring 4. If the end face is shaved, the shaft of the stepped gear 2a becomes short, causing problems such as poor meshing.

FIG. 3 is a perspective view for illustrating an example of the helical gear illustrated in FIG. 2.
The tooth surfaces of the helical gears 6 and 7 receive a force from gears (not shown) that mesh with each other, and a thrust force is generated in the axial direction (the direction along the arrow Yc in the drawing). If the helical gears 6 and 7 of FIG. 3 are attached like the gear shown in FIG. 2, the gear end surface 8 may come into contact with the E ring 4 depending on the rotational direction of the gears 6 and 7. The tooth surface (gear end surface 8) is shaved by the edge. If this continues, the axial direction of the helical gear will be shortened, which may cause problems such as poor meshing and contact with other parts.

FIG. 4 is a perspective view showing a helical gear according to an embodiment of the present invention.
The helical gear 7 is provided with a convex portion 9 as a hook portion on a part of the gear end surface 8. The convex portion 9 is shaped to fit the gap shape of the E-ring 4 and is installed so that the convex portion 9 is in the gap of the E-ring 4 during assembly (see FIG. 5).

FIG. 5 is a plan view showing a gear train of a driving device using a helical gear according to an embodiment of the present invention, and FIG. 6 is a perspective view showing a part of FIG.
The helical gear 2 b corresponds to the gear 7 as shown in FIG. 4, has a convex portion 9, and is assembled so as to be in the gap of the E-ring 4. By assembling in this way, when the helical gear 2b is rotated, the E-ring 4 is simultaneously rotated by the convex portion 9. Due to this action, the helical gear 2b receives a thrust force during rotation, and even if it contacts the E-ring 4, it does not slide between the helical gear 2b and the edge of the E-ring 4, and no scraping occurs.

FIG. 7 is a plan view showing a gear train of a drive device using a helical gear according to another embodiment of the present invention.
The convex portion 9a of the helical gear 7 according to the present embodiment has a shape in which a hook portion 9b is additionally provided in the circumferential direction so as to cover the E ring 4 on the tip end side in the axial direction. By adopting this shape for the convex portion 9a for rotating the E-ring 4, the E-ring 4 can be driven without being detached from the convex-shaped portion 9a when the helical gear 7 is rotated.

  The present invention is not limited to the embodiments described above, and many variations are possible by those having ordinary knowledge in the art within the technical idea of the present invention.

1: Gear 4: E-rings 5 to 7: Gear 8: Gear end faces 9 and 9 a: Convex-shaped part 9 b: Hook 40: Optical scanning device 50: Intermediate transfer belt 60: Transfer unit 70: Cleaning device

JP 7-249803 A

Claims (5)

A helical gear,
The helical gear is provided with a convex portion that can be mounted in the gap of the E-ring at the shaft end that is the tip side in the installation direction of the E-ring for positioning.
A helical gear characterized by that. The helical gear according to claim 1,
The helical gear is made of resin.
A helical gear characterized by that. A driving source having a gear for transmitting driving force;
The gear meshing with the drive source gear is a helical gear made of resin,
An E-ring for positioning the helical gear;
In the drive device in which the helical gear receives a thrust force in the installation direction of the E-ring,
The helical gear includes a convex portion that can be attached to the gap of the E-ring at the shaft end that is the tip side in the installation direction of the E-ring for positioning.
A drive device characterized by that. The drive device according to claim 3, wherein
The drive device according to claim 1, wherein the convex portion includes a hook portion having a shape covering the E ring at an axial end of the shaft of the helical gear. An image forming apparatus comprising the driving device according to claim 3.