JPH01254971A - Image recorder - Google Patents

Abstract

PURPOSE:To heighten rotational accuracy and to obtain a recording image of high definition by using an ultrasonic motor as a driving source which rotates a photosensitive body drum. CONSTITUTION:The ultrasonic motor is used as a driving source which rotates the photosensitive drum. That is, a guiding shaft 20 is fixed to the side plate 30 of a recorder, and a stator 1 and a fixing member 31 which prevents the guiding axis 20 from being pushed down are provided on the same shaft as the guiding axis 20. The photosensitive body drum 10 is composed by press- fitting a flange 11 made of an Al and a flange 14 made of a resin at both edging parts of a drum 16 on the surface of which the photosensitive body drum 10 is formed. When, voltages of which the phases are shifted with each other are impressed on polarized piezoelectric ceramics in the stator 1, turning power is given to a lining 13 pressed to an elastic body 3 is provided and the photosensitive body drum 10 turns with the guiding axis 20 as a center. Thus since any other mechanism is never included between the ultrasonic motor and the photosensitive drum, the rotational accuracy is heightened, and the unevenness of an image can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image recording apparatus that rotates a photoreceptor drum and exposes and records an image on the photoreceptor drum.
In particular, the present invention relates to a drive mechanism for the photosensitive drum described above.

[Prior Art] Devices that record an image by exposing the photosensitive drum to image light while rotating the photosensitive drum are currently widely used. Conventionally, in this type of image recording apparatus, an AC motor or a DC motor is used as a drive source for rotationally driving the photoreceptor drum, and the rotation of the motor is controlled via a speed change mechanism to control the rotation of the photoreceptor drum. The photosensitive drum was rotated by transmitting the signal to a gear provided on the forming surface.

The small AC motors and DC motors used in conventional drive mechanisms for photoreceptor drums cannot generate high torque when rotating at low speeds, so a speed change mechanism is used to reduce the output of the motor shaft that rotates at high speeds. By doing so, low speed rotation and high torque characteristics are obtained.

In the above-mentioned transmission mechanism, it is possible to have a large reduction ratio,
Gears are commonly used because they are inexpensive and easy to make compact. However, since gears are used in multiple stages to reduce the rotational speed of the motor shaft, there is a drawback that the rotational precision of the output shaft is significantly reduced due to variations in the precision of the gears and the precision between the shafts of the gears. Furthermore, there is also the drawback that the motor output transmission efficiency decreases due to multi-stage deceleration.

[Problems to be Solved by the Invention] The present invention aims to eliminate the drawbacks of the conventional photoconductor drum drive mechanism in which low speed rotation and high torque characteristics of the photoconductor drum are obtained by a speed change mechanism using gears as described above. It is something to do. For this purpose, the first feature of the present invention is to use a recently developed ultrasonic motor instead of the drive source using the above-mentioned AC motor or DC motor.

Ultrasonic motors are actuators based on a new principle of obtaining rotational force through ultrasonic vibrations, and have a much larger torque per unit volume than conventional AC or DC motors that rely on the interaction of current and magnetic fields. It is possible to obtain large torque output even at low speed rotation. Furthermore, the ultrasonic motor itself has advantages such as a simple configuration and excellent responsiveness. In particular, the above characteristics are
It is optimal for driving the photoreceptor drum of an image recording device, and since no speed reduction mechanism is involved, the rotation accuracy is extremely high, making it possible to obtain high-quality recorded images.

However, in order to generate the driving force, the above-mentioned ultrasonic motor uses an elastic body that generates a standing wave or a traveling wave due to vibration, and a so-called lining that presses against the elastic body and converts the traveling wave into rotational force. Therefore, wear due to sliding contact between the elastic body and the lining during rotation is a problem.

Specifically, when the elastic body or lining wears out, the driving force becomes unstable, and eventually, there is a major drawback in that the driving force no longer works.

A material with low internal loss and excellent wear resistance is suitable for the elastic body, and a material with a large coefficient of wear, excellent wear resistance, and does not generate friction noise is desired for the lining.

However, although the wear life of the elastic body and lining material determines the life of the ultrasonic motor, there are few materials that satisfy the above requirements, and even if there are materials, they are hard and difficult to machine. However, due to their high price, we have not yet developed a material that can ensure the same price and lifespan as conventional AC and DC motors.

Furthermore, even if a method is used to extend the life of the ultrasonic motor by replacing the elastic body or lining material during use, the ultrasonic motor itself must be disassembled, which has the disadvantage that only a skilled person can perform this work.

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention provides an image recording apparatus that rotationally drives a photoreceptor drum and exposes and records an image on the photoreceptor drum. The present invention provides an image recording device characterized in that an ultrasonic motor that drives using a standing wave or a traveling wave is used as a drive source for rotating a photosensitive drum.

Furthermore, the present invention provides an image recording apparatus using an ultrasonic motor as a drive source for rotating a photoreceptor drum as described above, in which the ultrasonic motor contacts a vibrating part of the ultrasonic motor and converts the vibration of the vibrating part into rotational force. To provide an image recording device in which a lining material is fixed to a photoreceptor drum.

[Function] According to the present invention, by fixing the lining material of the ultrasonic motor to the photoreceptor drum, each time the photoreceptor drum is replaced, a new lining material and the elastic body of the ultrasonic motor come into pressure contact with each other. can do.

[Examples] Examples of the present invention shown in FIGS. 1 to 5 will be described below. Among these figures, Figs. 1 to 3 show a recording device in which the present invention is implemented in a configuration in which a photosensitive drum is positioned along a guide shaft, and Figs. The present invention is implemented in a recording apparatus configured to position a photosensitive drum by inserting a shaft provided on the photosensitive drum into a bearing section.

In FIG. 1, reference numeral 1 indicates a stator, which includes a base 2 provided with polarized piezoelectric ceramics for generating vibrations, and a lining 13 for controlling the vibrations of the piezoelectric ceramics.
It is constructed by combining an elastic body 3 made of a material with high abrasion resistance to transmit the information.

A guide shaft 20 is fixed to a side plate 30 of the recording device,
A fixing member 31 for preventing the stator 1 and the guide shaft 20 from falling is provided coaxially with the guide shaft 20, as shown in FIG.
It is provided so that the side plate 30 is sandwiched between the stator top and the fixing member 31.

The photoreceptor drum 1 is a drum 1 having a photoreceptor formed on its surface.
It is constructed by press-fitting a flange 11 made of AJ2 and a flange 14 made of resin into both ends of the flange 6. The lining 13 is fixed to the flange 11, and a bearing 12 is further provided that is press-fitted while maintaining concentricity with the flange 11.

Bearing 1 is press-fitted into flange 14 while maintaining concentricity.
5 is provided.

By penetrating the photosensitive drum 10 into the guide shaft 20 with the flange 11 first, the elastic body 3 on the stator and the lining 13 are brought into contact. Furthermore, after the photoreceptor drum is inserted into the guide shaft 20, the collar 21 and the spring 2 are inserted.
2 into the guide shaft 20, and finally by screwing the nut 23 into the threaded part provided at the tip of the guide shaft 2o, the elastic body 3 and lining 13 generate torque during rotation by the force of the spring 2o. Obtain the appropriate pressing force required for this purpose.

In the above configuration, by applying phase-shifted voltages to the polarized piezoelectric ceramics in the stator ± to cause deflection vibration in the piezoelectric ceramics,
A traveling wave is excited in the elastic body 3, and the lining 13, which is in pressure contact with the elastic body 3, is given rotational force, and the photoreceptor drum -
The guide shaft 20 is rotated around the guide shaft 20.

The basic operating principle of the embodiments shown in FIGS. 4 and 5 is the same as that shown in FIGS. 1-3. In these figures, 1 denotes a stator, which, like the one shown in FIG. It is constructed by combining an elastic body 3 made of a material with high abrasion resistance for transmitting power to the body 13.

In FIG. 4, the photoreceptor drum 40 is constructed by forming a photoreceptor on the surface of a drum 41 with a shaft made by impact molding an aluminum block, and then fixing a lining 13 to the end of the drum where the shaft is formed. , on the other end surface,
It is constructed by press-fitting the shafted flange 42. Furthermore, a spring 43 and a collar 44 are attached to the shaft portion of the shafted flange 42.
has been penetrated.

The side plate 30 of the recording apparatus is provided with a sliding bearing into which the shaft of the shafted drum 41 penetrates, and the stator 1 is fixed to the sliding bearing 45 while maintaining concentricity.

A hole is made in the side plate 32 of the recording device so that the photoreceptor drum 40 can be inserted with plenty of room. A sub-side plate 33 provided with a bearing 46 is mounted on the side plate 32.

As shown in FIG. 4, the lining 13 of the photosensitive drum 40 supported by the sub-side plate 33 and the side plate 30 is pressed against the elastic body 3 on the stator by the force of the spring 43.

When a voltage is applied to the stator from an external drive circuit (not shown), the photoreceptor drum 40 is moved by sliding bearings 45 and 46.
Start rotating around the center.

In the embodiment shown in FIGS. 1 and 4, the lining 13 is fixed to the flange 11 and the shafted drum 41 made of a material with good thermal conductivity using an adhesive.
When the photosensitive drum 10 rotates once, the frictional heat generated by the elastic body 3 and the lining 13 is transferred to the flange 11.
, is quickly transmitted to the shafted drum 41, and the photosensitive drum-
10,40- Heat is radiated from the whole.

Due to the above-mentioned action, the area around the lining 13 is always maintained at a good temperature, and problems such as peeling of the lining due to burning of the pressure contact surface and deterioration of the adhesive will not occur.

[Effects of the Invention] According to the present invention, an ultrasonic motor that uses a standing wave or a traveling wave is used as a drive source for rotating the photoreceptor drum. In an image recording apparatus equipped with a mechanism, rotation accuracy is reduced due to variations in the accuracy of gears and accuracy between the axes of gears, etc., and unevenness in images is avoided.

However, by fixing the lining of the ultrasonic motor to the photosensitive drum, the lining can be easily replaced and the life of the ultrasonic motor can be significantly extended.

In the present invention, the wear resistance life of the lining material can be set to be equal to the life of the photoreceptor, so there is no need to use a special material, and general resins such as polyimide resin can be used.

The present invention makes it possible to obtain the same rotational performance as a new ultrasonic motor every time a new photoreceptor drum is replaced.
It is possible to avoid performance deterioration of the drive mechanism during long-term use, which has been a problem in conventional devices.

Furthermore, in the present invention, since no other mechanism is interposed between the ultrasonic motor and the photoreceptor drum, the ultrasonic motor's excellent characteristics of ``generating high torque even at low rotation speeds and having extremely high rotation accuracy'' are achieved. This not only makes it possible to use the ultrasonic motor as is, but also makes it possible to make the ultrasonic motor smaller and lower in price.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a photosensitive drum and its driving mechanism in a first embodiment of an image recording apparatus according to the present invention, and FIG. 2 is a state in which the apparatus shown in FIG. 1 is not equipped with a photosensitive drum. 3 is a perspective view of the apparatus shown in FIG. 1, and FIG. 4 is a side view showing a photosensitive drum and its driving mechanism in a second embodiment of the image recording apparatus according to the present invention.
FIG. 5 is a side view showing a state in which the photosensitive drum of the apparatus shown in FIG. 4 is not attached to the drive mechanism.

Claims (1)

[Scope of Claims] 1. In an image recording apparatus that rotates a photoreceptor drum and exposes and records an image on the photoreceptor drum, a standing wave or a traveling wave is used as a driving source for rotating the photoreceptor drum. An image recording device characterized by using an ultrasonic motor that is driven using waves. 2. The image recording apparatus according to claim 1, further comprising a lining material fixed to the photoreceptor drum, the lining material being in contact with the vibrating part of the ultrasonic motor and converting the vibration of the vibrating part into rotational force.