JPS63154363A - Printer head - Google Patents

Abstract

PURPOSE:To reduce the loss in printing energy and enhance the printing ability of a printer head, by providing electromagnetic drivers for independently driving each printing lever to supply printing energy to printing element return springs provided for the printing elements, and magnets for applying returning forces to the printing elements together with the return springs. CONSTITUTION:With a printing signal supplied to a driving coil 8, a core piece 7 is magnetized, and a printing lever 5 is attracted thereto. The lever 5 is oscillated with an outer end part thereof as a center, whereby an inner end part is advanced. Therefore, a printing element 1 is supplied with printing energy from an electromagnetic driver 6, and is advanced, thereby printing. When printing is finished, the attracting force of the core piece 7 is no longer applied to the lever 5, so that the printing element 1 is retracted to an initial stand-by position under the resultant force of a spring force of a return spring 3 and an attracting force of a magnet 11. Thus, the returning force exerted on the printing element is supplied by the return spring and the magnet, and the force is constantly uniform and approximately equal to a required minimum returning force. Therefore, the loss in printing energy is small, printing ability is enhanced, and response characteristic is favorable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an impact type printer head.

(Prior Art) A conventional printer head includes one (1) electromagnetic drive device for respectively driving a drive arm corresponding to a plurality of printing elements. Each printing element is equipped with a coil spring or a leaf spring. The printing element is moved forward by an electromagnetic drive device to perform printing, and then retreated to a standby position by the return spring.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, the return force of the printing element is obtained by the return spring, so as the blank outline moves forward during printing, the spring force of the return spring, that is, the return force increases. This acts as a loss of printing energy and reduces printing performance.

Therefore, if the spring force of the return spring is set small, bounce will occur at the standby position upon return, resulting in poor response. Furthermore, if an attempt is made to reduce the increase in the spring force of the return spring during printing, the return spring becomes larger. Furthermore, increasing the printing energy causes the problem of heat generation in the printer head.

An object of the present invention is to minimize the increase in return force while the printing element advances from the standby position to the printing position,
It is configured so that the minimum required uniform return force is applied to the printing element, reducing the loss of printing energy and improving printing performance, enabling printing with low input energy and reducing the amount of heat generated by the printer head. It's about letting people know.

(Means for Solving the Problems) The present invention is characterized by being able to swing freely using the outer end as a fulcrum;
A plurality of printing levers that drive the printing element at the inner end, an electromagnetic drive device that independently drives each printing lever to apply printing energy to the printing element, a return spring provided on the printing element, and a printing lever. A magnet is disposed on the back side of the inner end of the printing element and applies a return force to the printing element along with a return spring.

(Function) In the present invention, the return force of the printing element is a combined force of the spring force stored in the return spring and the attraction force of the magnet. As the printing element advances, the spring force of the return spring gradually increases in proportion to the distance, while the attractive force of the magnet gradually decreases in inverse proportion to the square of the distance. For this reason, the combined force of both becomes almost uniform. And the loss of printing energy during printing is reduced. When the printing element returns, contrary to the above, the spring force of the return spring gradually decreases, but the attraction force of the magnet increases rapidly, so the printing element quickly returns to the standby position without bouncing.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

As shown in the first figure, a printing wire 1, which is a printing element, slidably passes through a wire guide 2a of a head frame 2 made of plastic. It goes without saying that a plurality of printing wires 1 are actually provided and are supported by a plurality of wire guides. A coil spring 3, which is a return spring, is fitted to the rear end of the printing wire 1, and a printing bottle 4 is fixed to the rear end.

A printing lever 5 corresponding to each printing element 1 is arranged centrially and drives the printing element 1 at its inner end. In this example, the movement of the printing lever 5 is transmitted to the printing element 1 by providing a small diameter portion 4a on the printing pin 4 and engaging the small diameter portion 4a in a U groove 5a provided at the inner end of the printing lever 5. It is configured so that The printing lever 5 is swingable about its rear end as a fulcrum, as will be described later.

An electromagnetic drive device 6 for driving each print lever 5 is composed of a U-shaped core piece 7 made of a magnetic material and a drive coil 8 wound around a leg piece 7a inside the core piece 7. The core piece 7 is attached to the head frame 2 at the front end surface of a connecting piece 7C that connects the inner leg piece 7a and the outer leg piece 7b. The outer end of the printing lever 5 is pressed against the rear end surface of the outer leg piece 7b, and is attracted to the rear end face of the inner leg piece 7a, so that the print lever 5 is printed on the printing element 1. ! The printing energy of the electromagnetic drive is applied.

Reference numeral 9 denotes a back cover, to the inner surface of which a presser spring 10 and a magnet 11 are fixed. The presser spring 10 has its outer end pressing the outer end of the printing lever 5 against the rear end surface of the leg piece 7b, so that the printing lever 5 can swing freely about the rear end. The magnet 11 is located on the back side of the inner end of the print lever 5, and the attraction force of the magnet 11 and the spring force of the return spring 3 are combined to apply a return force to the print element 1. There is a stopper plate 1 on the front of the magnet 11.
2 is attached to protect the magnet 11 from the impact when the printing element 1 returns.

With this structure, when the drive coil 8 is not energized, the printing lever 5 is moved to the core piece 7 as shown by the solid line.
The printing element 1 is at a standby position where it is attracted by the magnet 11 and retreated. When a print signal is supplied to the drive coil 8, the core piece 7 is magnetized and the print lever 5 is attracted to it. The inner end of the printing lever 5 moves forward by swinging around the outer end.

For this purpose, the printing element 1 is given printing energy by the electromagnetic drive device 6 and moves forward to print. When printing is finished, the attraction force from the core piece 7 is no longer applied to the printing lever 5, so the printing element 1 retreats under the combined force of the spring force of the return spring 3 and the attraction force of the magnet 11. to return to the original standby position.

Next, with reference to FIG. 2, the return force exerted on the printing element 1 will be explained in detail. FIG. 2 shows the return force acting on the printing element in response to the movement of the printing element, with the return force on the vertical axis and the amount of movement of the printing element on the horizontal axis. Note that the standby position of the printing element is O, and the printing position is P. The curved line indicates the return force of the conventional return spring, and if the setting is made to obtain the minimum required return force, a large return force will be applied to the printing element at the printing position P, and naturally this return force will be applied to the printing element at the printing position P. It can be seen that the force is a large loss in printing energy. Curve B shows the return force of the return spring 3 used in the present invention, and the spring used has an extremely smaller return force than the conventional return spring. Although the return force increases as it approaches the printing position EP, it does not exceed the minimum necessary return force. A curve C indicates the attraction force of the magnet 11, which rapidly decreases as it approaches the printing position P. Curve A is a composite of curve B and curve C, and shows the restoring force that actually acts on the printing element 1 in the present invention. In this manner, at the standby position O, the small spring force of the return spring 3 and the large attraction force of the magnet 11 are combined to provide the minimum necessary return force. Further, at the printing position P, the large spring force of the return spring 3 and the small suction force of the magnet 11 are combined to provide the minimum necessary return force. Further, even at an intermediate position between the standby position ◯ and the printing position P, one of them decreases and the other increases, so that a minimum necessary return force and a substantially uniform return force are applied. In this way, in the present invention, since a uniform force that is almost equal to the minimum necessary restoring force is always applied to the printing element 1, printing can be performed by inputting sufficient energy to exceed this restoring force. Printing is performed with almost no loss of energy, and it can be driven with less input energy than before.

(Effects of the Invention) As explained above, according to the present invention, the return force of the printing element is given by the return spring and the magnet, and is always a uniform force that is almost equal to the minimum required return force. Less energy loss, improved printing ability, and better responsiveness. In addition, less input energy is required and less heat is generated in the printer head, which is particularly effective for high-speed printers. Furthermore, since less heat is generated, the heat dissipation configuration can be simplified, which is effective in reducing costs.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a cross-sectional view of the main part, and FIG. 2 is an explanatory diagram illustrating the restoring force acting on the printing element. DESCRIPTION OF SYMBOLS 1... Printing element, 3... Return spring, 5... Printing lever, 6... Electromagnetic drive device, 11... Magnet. that's all

Claims (1)

[Scope of Claims] A plurality of printing levers that are swingable about an outer end as a fulcrum and that drive a printing element at an inner end, and each printing lever is independently driven to apply printing energy to the printing element. a return spring provided on the printing element; and a magnet provided on the back side of the inner end of the printing lever and applying a return force to the printing element together with the return spring. printer head.