JPH0643808Y2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus using an electrophotographic process, and in particular, a process unit such as a photoconductor, a cleaner, and a developing unit detachably attached to a main body of the image forming apparatus. The present invention relates to a drive transmission device that transmits a drive from a main body of an apparatus to a process unit when mounted.

[Prior Art] In recent years, in image forming apparatuses such as electrophotographic printers, PPC copiers, etc., maintenance is performed by a disposable method in which process parts such as a developing device, a photoconductor, and a cleaner are unitized and are replaced when they reach the end of their lives Simplifying systems are becoming common. In this case, it is necessary to obtain a driving force from the apparatus body when the process means such as the developing device is attached to the apparatus body. As a mechanism for transmitting this driving force, there is, for example, a structure disclosed in Japanese Utility Model Laid-Open No. 61-44027. In the method disclosed in this publication, three major components of the drive transmission mechanism are a member for aligning the axes, a member for transmitting drive, and a member for spring-biasing the drive transmission member.

[Problems of Prior Art] However, in the drive transmission device as described above, at least three members are required for transmitting the drive, and the mechanism is complicated and the cost is high. Further, backlash of the drive transmission member causes uneven rotation of the driven member. For example, when the driven member is a photoconductor, the uneven rotation as described above appears as an image blur, and sometimes becomes unusable. Rotational irregularity occurs especially when the cores of the shaft-aligning member and the drive transmission member are misaligned, but it is extremely difficult to manufacture parts that have no misalignment of the cores, and minute rotational irregularities always occur. There is a defect.

[Object of the Invention] In view of the above-mentioned conventional drawbacks, the present invention is capable of easily aligning a rotary shaft when driving a process unit detachably attached to an image forming apparatus main body, and at the same time, a drive transmission device without uneven rotation. An object of the present invention is to provide an image forming apparatus having the above.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is an image forming apparatus in which process means necessary for image formation are unitized and detachably attached to an apparatus main body. The rotor is provided in the process means, and the rotor and the stator are loosely inserted by mounting the process means.

Embodiments of the Invention Embodiments of the present invention will be described in detail below with reference to the drawings.

1 and 2 are cross-sectional views in which the present invention is applied to drive a photoconductor, FIG. 3 is a cross-sectional view of a drum unit in which a photoconductor, a cleaner and a charger are unitized, and FIG. 4 is an image forming apparatus. FIG. 6 is a perspective view showing the mounting of the process unit to the.

In FIG. 4, an image forming apparatus 1 is an electrophotographic apparatus in which process means such as a charger, an exposure device, a developing device, a transfer device, and a cleaner are arranged around a photoconductor, and a laser, an LED, a liquid crystal or the like is used as the exposure device. Examples thereof include the electrophotographic printer used and an electrophotographic copying machine that exposes a document image onto a photoconductor using an optical system. The image forming apparatus 1 is composed of an upper machine body 2 and a lower machine body 3, and is configured to open like a shell with one end as a fulcrum to facilitate treatment of paper jams and the like. Further, among the process means, the photoconductor, the charging device, the developing device, and the cleaner are long-life parts and cannot be used further if a certain number of printed sheets is used. For example, the photoreceptor has a decreased photosensitivity characteristic, the charger has a reduced discharge ability due to dirt or oxidation of corona discharge lines, the developer has a deteriorated carrier or lack of toner, and the cleaner has a life due to wear of a cleaning blade. In the image forming apparatus of the present invention, the above-mentioned service life parts are unitized and replaced by the operator to simplify the maintenance.

Reference numeral 4 is a developing unit in which a developing device is unitized, and 5 is a drum unit in which a photosensitive member, a charger, and a cleaner are unitized, and both units are detachably attached to the main body of the image forming apparatus 1.

FIG. 3 is a cross-sectional view of the drum unit 5, and the drum unit 5 is integrally configured in a casing (not shown) by the photoconductor 6, the charger 7, and the cleaner 8. Reference numeral 9 is a blade for cleaning the untransferred toner on the photoconductor 6, and reference numeral 10 is a toner transporting roll for transporting the cleaned toner to a collecting unit (not shown).

The photoconductor 6 or the toner transport roll 10 described above needs to be rotated at a predetermined speed, and when the drum unit 5 is mounted on the main body of the image forming apparatus 1, it is necessary to receive drive transmission from the main body of the apparatus.

The above-mentioned drive transmission will be described in detail below with reference to FIGS. 1 and 2 using the photoconductor 6 as an example. The photoconductor 6 includes a drum 6a, an end bracket A6b, and an end bracket B6c,
A shaft 6d is provided on the end bracket A6b. The axis 6
d is pivotally supported by a bearing 11a provided in the casing 11.

On the other hand, reference numeral 12 is a stator of an ultrasonic motor provided in a housing 13 of the image forming apparatus main body, and the stator 12 and an end bracket B6c which is a rotor constitute the ultrasonic motor.

The operation of the drive transmission mechanism having the above-described structure will be described with reference to FIGS. 1 and 2 similarly to the above.

FIG. 2 is a diagram showing a state immediately before the completion of mounting the drum unit 5 on the apparatus main body, and the mounting is completed as shown in FIG. 1 by further inserting the drum unit 5 in the arrow direction. At this time, the center hole 15 of the end bracket B6c is guided by the guide shaft 14 provided in the central portion of the stator 12, and even if the center of the guide shaft 14 and the center of the center hole 15 are slightly deviated, alignment is possible. As shown in the figure, the tip of the guide shaft 14 is tapered in a taper shape, and the opening of the center hole 15 is also formed in a large diameter in a taper shape, so that the aligning operation is configured to be performed reliably. There is. The mounting of the drum unit 5 is completed by the abutment of the tip of the guide shaft 14 and the deepest part of the center hole 15, and at this time, the stator is
The twelve vibrators 16 and the groove 17 provided in the end bracket B6c, which is the rotor, are mounted at a position having a predetermined gap.

By applying a predetermined voltage to the stator 12 of the ultrasonic motor, the vibrator 16 is driven and the end bracket B6c, which is the rotor, is rotated and the photoconductor 6 is rotated. Due to its structure, the ultrasonic motor does not require windings as in the past,
Most suitable for high torque loads. Further, since the rotation unevenness is extremely small, it is particularly suitable for driving the photoconductor. Further, the end bracket B6c, which is the rotor, may be made of metal or resin, and particularly when resin is used, it can be constructed inexpensively and lightly,
It can be used for disposable units without problems.

Although the above embodiment has been described with respect to the driving of the photosensitive drum, the present invention is not limited to this and can be applied to other process means such as a developing sleeve, a toner conveying roll in a cleaner, or a fixing roll. Is.

[Advantages of the Invention] As described in detail above, according to the present invention, since the rotor of the ultrasonic motor is configured as the end bracket of the disposable unit, for example, the photosensitive drum, the alignment can be surely performed when the unit is mounted, and the rotation unevenness can be further ensured. It is possible to obtain a drive transmission device that does not have an image blur, and it is possible to provide an image forming device that does not cause image blur.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are cross-sectional views when the present invention is applied to drive a photoconductor, and FIG. 3 is a cross-sectional view of a drum unit in which the photoconductor, cleaner and charger are unitized, FIG. 4 is a perspective view showing how the process unit is attached to the image forming apparatus. 1 ... Image forming device, 4 ... Developing unit, 5 ... Drum unit, 6 ... Photoconductor, 6c ... End bracket B, 12 ... Stator, 13 ... Housing, 14 ... Guide shaft,
16 …… Resonator, 17 …… Groove.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-60-183981 (JP, A) JP-A-61-86332 (JP, A) Practical application Sho-62-201774 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. An image forming apparatus in which process means necessary for image formation are unitized and detachably attached to an apparatus main body, wherein a stator of an ultrasonic motor is provided in the apparatus main body and a rotor is provided in the process means. An image forming apparatus in which the rotor and the stator are loosely inserted by mounting process means.