JPS60257274A - Driving mechanism for feeding paper - Google Patents

Abstract

PURPOSE:To contrive a smaller size, a higher efficiency and reductions in the number of component parts and weight, by a construction wherein a rotor connected to a platen shaft is pressed against an elastic body, a piezoelectric element is provided on the surface of the elastic body, a detecting means for the rotating quantity of the rotor is provided, the rotor is formed from brass, and the elastic body is formed from a mild steel material. CONSTITUTION:The platen 6 with a printing paper set thereon is directly connected to the driving mechanism through the platen shaft 5, and is driven to rotate. The shaft 5 is provided with a gear 8 for detecting the rotating quantity thereof, and the rotating quantity is detected by a magnetic sensor 9. The rotating quantity thus detected is fed back to a driving system by a controlling mechanism to perform feedback control. By a surface wave generated from the piezoelectric element 1, a driving force for low- speed, high-efficiency and high-torque rotation is exerted on the rotor 3, thereby driving a paper-driving shaft 5 to feed the paper. In this case, the rotor 3 is formed from a brass material, while the elastic body 2 is formed from a mild steel material. Accordingly, since both of the rotor 3 and the elastic body 2 have a high coefficient of surface friction, a surface with a high coefficient of friction is provided at a contact part of the rotor 3 and the body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feed drive mechanism used in a printer.

[Prior art]

A conventional paper feed drive mechanism used in a printer uses a DC motor, a step motor, or the like as its power source, and drives a paper drive shaft from the drive source via a timing belt or a gear train.

Due to this structure, space for the motor is required and the number of parts is large, which limits the ability to make the device smaller and lighter. Also, since there are many mechanical parts, improvements were desired in terms of improving reliability.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feed drive mechanism for use in a printer that is small, highly efficient, has a small number of parts, and is lightweight.

[Structure of the invention]

The paper feed drive mechanism of the present invention includes a platen around which printing paper is wound, a platen shaft that drives the platen, a rotor having a high friction coefficient surface directly connected to the platen shaft, an elastic body, and the rotor. A paper feed drive mechanism comprising: a pressure contact member that presses the elastic body against the elastic body; a piezo element that is attached to the elastic body and generates a surface acoustic wave on the surface of the elastic body; and a means for detecting the amount of rotation of the rotor. The rotor is made of brass material, and the elastic body is made of soft material. , [Example] Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a known surface acoustic wave drive mechanism. Reference numeral 3 indicates a rotor having a surface with a high coefficient of friction, 2 an elastic body pressed against the rotor, and 1 a piezo element that generates surface acoustic waves. The surface acoustic waves generated in the piezo collector 1 are transmitted on the surface of the elastic body C as shown in the figure. Due to these surface acoustic waves, the rotor 3 is moved by Δ in the direction opposite to the direction in which the waves travel.

FIG. 2 shows an embodiment of the present invention which utilizes this principle and is a rotary type partial movement mechanism. There is a rotor 3 having a surface with a high coefficient of friction in the center, and an elastic body 2. A piezo element 1 is arranged as shown in the figure, and is pressed against a rotor 3 by an elastic body 2 and a pressing mechanism 4. Similar to the operating principle described above, the rotor is driven and rotated by surface acoustic waves generated by the piezo element 1. At this time, it generates higher torque at lower speeds than other conventional motors. In addition, the well-known piezo is compact, lightweight, and highly efficient.

The platen on which printing paper is mounted is directly connected to this drive mechanism via a platen shaft 5 and is rotationally driven. A gear 8 for detecting the amount of rotation is attached to the platen shaft 5, and the amount of rotation is detected by a magnetic sensor 9 provided separately.

The detected amount of rotation is controlled to be fed back to the drive system by a control mechanism. The surface waves generated by this piezo element provide the rotor 3 with a rotational drive at low speed, high efficiency, and high torque that has never been seen before, and drives the paper drive shaft 5 to feed the paper.

This eliminates the need for conventional gear trains and timing belts, which not only reduces the size of the device, but also improves reliability.
It brings advantages of multiple dogs such as lower cost. The material of the 7-rotor 3 is made of brass, and the material of the elastic body 2 is made of mild steel. As is well known, the coefficient of surface friction between high quality steel and mild steel is larger than that of other combinations of metals, and a surface with a high friction coefficient is formed at the contact area between the rotor 3 and the elastic body 2, and the paper feed drive with the above configuration ) The same effect as mentioned above is brought about in several structures, and since they are both made of inexpensive materials, they are effective in reducing costs.

〔Effect of the invention〕

As explained above, the present invention utilizes a piezo element to realize a high-output, small-sized, lightweight rotational drive mechanism, thereby achieving a highly reliable, low-cost, small-sized, lightweight printer's paper feed mechanism.
! The effect of providing an A-motion mechanism is ascertained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the principle of well-known surface acoustic wave drive, and an embodiment of the paper feed drive mechanism of the present invention. It is a front view. l...Piezo element, 2...Elastic body, 3
...Rotor, 4... Pressure contact member, 5...
...Platen shaft, 6...Platen,
8...Rotation amount detection gear, 9...Rotation amount detection sensor 6° 1st Fig. 7 Fig. 2

Claims (1)

[Claims] A platen around which printing paper is wound, a platen shaft that drives the platen, a rotor having a high friction coefficient surface directly connected to the platen shaft, and an elastic body.
The rotor is comprised of a pressure contact member that presses the rotor against the elastic body, a piezoelectric element that is attached to the elastic body and generates surface acoustic waves on the surface of the elastic body, and means for detecting the amount of rotation of the rotor. A paper feed drive mechanism characterized in that the rotor is made of brass and the elastic body is made of mild steel.