JPS58102786A - Printing head - Google Patents

Abstract

PURPOSE:To miniaturize the printing head by driving a printing hammer, and to increase the speed of printing and reliability by mounting the printing hammer into a magnetic loop formed by a permanent magnet and mechanically changing the magnetic loop. CONSTITUTION:When a magnetic shielding disk 26 is turned and through holes 28 are formed between the permanent magnet 12 and a yoke 15, the magnetic circuit of the printing head 21 is shaped in an open magnetic circuit, a printing hammer chip 13 gives an ink ribbon 10 and a type wheel 17 a shock, and characters are formed onto a form 20. When the magnetic shielding disk 26 is further turned and magnetic substances 29 are positioned between the permanent magnet 12 and the yoke 15, the magnetic circuit of the printing head section 21 is shaped in a closed magnetic circuit, an armature 14 is absorbed to the yoke 15, and the printing hammer chip 13 is brought to the state of print-waiting.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel printhead that is high speed, highly reliable.

Conventional print heads use a magnetic circuit composed of permanent magnets (1) as shown in Figure 1. In the standby state, the permanent magnets (1)
) The printing hammer (2) is attracted by the magnetic attraction force of
During the printing operation, the excitation coil (3) on the magnetic circuit is energized to apply a reverse magnetic field to release the attraction of the printing hammer (2). Printing was performed by striking the paper (7) wrapped around the platen (6) with the activation wheel (5) using the elastic force of step 4). (8) is an ink ribbon.

In such a method, the temperature rise in the print head is large due to Joule heat caused by the current flowing through the excitation coil (3), and especially when printing at high speed, the temperature rise in the print head is 120 degrees.
Since the temperature reaches close to °C, it was necessary to design the print head with sufficient consideration for heat dissipation. Therefore, there is a limit to high-speed printing, and the coil winding process in the print head assembly work is complicated and requires many man-hours, which is a factor in high costs.

Furthermore, since the coil has inductance, there is a limit to the printing speed.

In order to solve the above-mentioned drawbacks, the print head of the present invention does not use any excitation coil, but mechanically changes the permeance of a magnetic circuit composed of permanent magnets to release the attraction of the printing hammer and obtain printing operation. In this system, a magnetic loop such as a permanent magnet is constructed, a printing hammer is provided within this magnetic loop, and the printing hammer is driven by opening and closing the magnetic loop.

The present invention will be described below based on drawings showing embodiments. First, the first embodiment will be explained based on FIGS. 2 to 5 showing the first embodiment.

In the figure, (b) is a yoke. One end of this yoke αρ has a permanent magnet @, and the other end has a hammer tip (printed on the tip).
2) is fixed, and the base end of the armature (b) of the leaf spring made of a magnetic material is fixed with screws or the like. (G) is a yoke attached to the yoke (B) via a non-magnetic frame (C), which is formed in an L shape, one end of which faces the tip of the armature Q4, and the other end of which is attached to the yoke (B) via a non-magnetic frame (C). facing the permanent magnet) with a gap therebetween, and the yoke 00. Permanent magnet threat,
A magnetic circuit is constituted by the armature Q4.

A flexible type wheel (B) made of resin or the like is arranged in front of the armature (B), and the platen (to) of the printing hammer tip (2) on the armature (B) is placed in front of the armature (B).
It is configured such that printing is performed on the paper wrapped around the surface of the platen (to) via the di-ink ribbon (a) by impact in the direction. Also, the above-mentioned yoke a, permanent magnet (2), printed hammer tip (to), armature (b), yoke OQ
A print head section (2) consisting of a non-magnetic frame 00 and a non-magnetic frame 00 is mounted on a carriage (2), which is guided by a carriage guide shaft (2) and reciprocates against a platen. The type wheel (b) is formed into a petal shape as shown in FIG.
C) is formed. Also, this type character selector motor (2) is fixed to a type selection motor (2) attached to the carriage plate.

The rotation of the motor is controlled so that the desired type (c) can be selected. (E) is a magnetic continuous disk.

This is fixed with screws or the like to the shaft (27a) of the motor (b) which is fixed to the carriage (2). In addition, as shown in Fig. 4, this magnetic continuous disk (2) has through-holes and magnetic rods alternately arranged at equal intervals on the same circumference near the outer periphery, and the print head section). It is rotatably arranged between the yoke (b) and the permanent magnet Qa, and the print head part (b)
The magnetic circuit is configured to change the permeance of the magnetic circuit. In addition, an ink ribbon drive shaft is integrally formed in the center of the magnetic continuous disk (2), and an ink ribbon cassette (
(b) The ink ribbon feeding roller is housed in (b) and is configured to be removably fitted into the ink ribbon feeding roller (b). Further, the rotation of the magnetic continuous disk (e) is accurately controlled by a rotating disk sensor, and the permeance of the magnetic circuit of the print head section (2) is also accurately controlled.

Next, the operation will be explained according to FIG. FIG. 8(3) shows a print standby state. In this state, the permanent magnet (
A magnetic shielding disk is interposed between the yoke head and the yoke head. At this time, the magnetic circuit (in the print head section) comprises a yoke (b), a permanent magnet stem, an armature α4, and a closed path through the yoke a.

That is, the armature Q4 is attracted to the yoke (2) and the printing hammer tip (to) is in a printing standby state. here.

The elastic force due to armature α→ is fs, and the printing force is F.

The magnetic attraction force is fφ1. Let the magnetic force during continuous operation be f6.

However, force due to magnetic flux = f^ [Figure 8 (4)] Force due to magnetic flux = f6 (Figure 8 (8)) and fat >
fs-...■ ^)h -・-・■fl'z <-
Since the print head section (2) is configured such that the following four equations: fs - - *F=fsl -fdz =-■ hold true, the above-described print standby state is established. Next, Figure 8C
B) is a printing operation state. Now magnetic closing disc (to)
is rotated by a motor, its position is controlled by a rotating disk sensor), and a through hole (c) is interposed between the permanent magnet (b) and the yoke (g), and the print head is formed. The magnetic circuit in section (2) becomes an open magnetic path. In other words, ■,■ in the above equation
and 0 are established, the printing hammer tip O strikes the ink ribbon (to) and the type wheel Qη, forms characters on the paper (to), and a printing operation is performed. Further rotate the magnetic interlocking disk (E) as shown in Figure 8 (2).
In this state, the printing hammer tip 01 becomes in a standby state. Therefore, by continuously rotating the continuous magnetic disk, printing can be performed continuously, and a high-speed printing head can be obtained. In addition, magnetic continuous disk (7
) has an integrated ink ribbon drive shaft, so the ink ribbon (a) is fed in synchronization with the printing operation, eliminating the need for an ink ribbon drive motor, simplifying the configuration and reducing costs. This means that it is possible to achieve higher speeds. Furthermore, since the print head with the above configuration does not require an excitation coil, there is no need to consider coil inductance, there is no temperature rise due to the coil generating Joule heat, and there is no need to consider heat dissipation design. The head can be made smaller and a hood can be provided for printing with high reliability and high speed. Further, since there is no excitation coil, the number of assembly steps can be reduced, and the cost can be reduced by eliminating the need for the motor for driving the ink ribbon. In the above embodiment, a permanent magnet (2) was arranged in the print head part to form a magnetic circuit, and the permeance of the magnetic circuit was changed by a magnetic shielding disk member. ), the magnetic loop main body side consisting of permanent magnet @, armature α→, and yoke Oυ is all made of high magnetic permeability magnetic material), and the magnetic shielding disk @ side is composed of permanent magnet to improve the permeance of the magnetic circuit. A similar effect can be obtained by changing □.

Furthermore, the magnetic connecting disk) is made of a high magnetic permeability sulfuric material, and the rim is made of pure iron or sulfuric steel plate, etc., and is shaped like a petal as shown in Figure 6.

Alternatively, as shown in FIG. 7, openings (b) may be formed at equal intervals. That is, various modifications can be made without departing from the spirit of the invention.

The print head of the present invention can be implemented as described above, and the printing hammer can be driven by mechanically changing the permeance of a magnetic circuit made up of permanent magnets without using any excitation coil. Therefore, there is no need to design the coil in consideration of Joule heat, and it is possible to provide an inexpensive print head with a simple configuration, small size, high reliability, and high speed.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of main parts showing a conventional example, Figs. 2 to 5 show a first embodiment of the present invention, Fig. 2 is a cutaway front view of main parts, and Figs. 3 (A) [F] ) is an explanatory diagram of the operation of the print head section, No. 4
FIG. 5 is a front view of a type wheel, and FIG. 6 and FIG. 7 are plan views of magnetic interconnection disks in other embodiments of the present invention. α】)・−・Yoke, (6)・−・Permanent magnet, (to)・・
・Printing hammer tip, Q4-°° armature, (to)-・yoke, (b)...type wheel, (to)...
Platen, (IL-ink ribbon, (a)... paper,
＠-・Print head section%)-carriage, (support)...
Type selection motor (in)...magnetic interlocking disk (in)
- Motor, (c)...Through hole, (2)...Magnetic agent Yoshihiro Morimoto Figure 1 7 Figure 2 2 Figure 3 (B) 7 Figure 4

Claims (1)

[Claims] 1. A print head comprising a magnetic loop made of a permanent magnet, a printing hammer provided within the magnetic loop, and driving the printing hammer by opening and closing the magnetic loop. 2. By installing a permanent magnet on the magnetic loop body side and moving a high permeability magnetic material into and out of this magnetic loop body)
2. The print head according to claim 1, wherein the print head is configured to open and close a magnetic loop to attract and remove a printing hammer to perform a printing operation. 8. The magnetic loop main body side is made of high permeability magnetic material,
Claim 1: The magnetic loop is opened and closed by moving a permanent magnet into and out of the magnetic loop main body, and the printing hammer is attracted and removed to perform a printing operation.
Print head as described in section. The print head according to claim 2, wherein the movement of the high magnetic permeability magnetic material into and out of the magnetic loop body is performed using the rotational force of a motor. 5.7. 9. The print head according to claim 8, wherein the permanent magnet is moved into and out of the magnetic loop body using the rotational force of a motor. & Moving the permanent magnet or high permeability magnetic material into and out of the magnetic loop and feeding the ink ribbon I! The print head according to claim 1, wherein the printing operation and the ink ribbon feeding operation are synchronized by using the same drive mechanism.