JPS6073854A - Dot printer - Google Patents

Abstract

PURPOSE:To suppress the rebound phenomenon of printing wires by varying exciting power to make it smaller as the distance between the tip of the printing wire and a platen becomes smaller. CONSTITUTION:When an eccentric cam 5 undergoes an angular displacement and the interval between the tip 13a of a printing wire 13 and a platen 10 is largely set, the resistance value of a variable resistor 22 is small. When the tip 13a of the wire 13 is regulatively set by the eccentric cam 5 in such a way as to enable it to come near the platen 10, the resistance value of the resister 22 is greatly varied. Exciting current flowing in the coil 15 is therefore smaller as shown by a reference mark 2. As the interval between the tip 13a of the wire 13 and the platen 10 becomes smaller, the exciting power is less changed. The operating speed of the wire 13 is therefore reduced, and the returning speed of the wire 13 becomes smaller. The rebound phenomenon of the printing wire 13 can thus be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical details: The present invention excites an electromagnet to drive an amatia, and the amatia hits the head of the printing wire against the force of the splash to move the printing wire onto the platen. This invention relates to a so-called free flight type dot printer that performs Lit toward the target.

In such a so-called free-flight dot printer, the head of the printing wire collides with the ammathia, causing the printing wire to vibrate, resulting in so-called rebound. This deteriorates the quality of the "-" characters. Such rebound of the print wire is more likely to occur as the return speed of the print wire is greater. The return speed of the print wire increases as the number of recording sheets stacked on the platen decreases. That is, depending on the number of sheets of recording paper, the repulsion of the print wire becomes more pronounced, and when the number of sheets of recording paper is small, the repulsion occurs more frequently.

OBJECTIVES An object of the present invention is to provide a dot printer that can suppress the rebound phenomenon of printing wires.

Embodiment FIG. 1 is a simplified side view of one embodiment of the present invention. Move the printer head 1 along the guide 3 for 1 mJ E
Located in J&. This printer head 1 has
Hollow 4 is determined. A cam surface of an eccentric cam 5 contacts the follower 4. The follower 4 is resiliently brought into contact with the cam surface of the eccentric cam 5 by the spring 6. The eccentric cam 5 moves the printer head 1 toward and away from the platen 10 by angularly displacing a lever 8 fixed to the eccentric cam 5 having a rotating shaft 7 around the rotating shaft 7 as indicated by an arrow 9. mutual lul between printer head l and platen lo.
+ You can adjust the interval. platen l.

One or more recording sheets 11 are provided above, and an ink ribbon 12 is placed on this recording sheet 11. Printing is performed on the recording paper 11 by driving a printing wire 13 from the printer head 1 to the platen 10. Depending on the recording wind 11 and the thickness of the ink ribbon 12, the number of recording sheets 11, etc., the printer head l adjusts the distance between the printer head l and the platen 10 using an eccentric cam 5.
It is facilitated to make M.

FIG. 2 shows the configuration related to the printing wire 13 of the printer head 1 in a 112-page format. A coil 15 is wound around the core 14 to constitute an electromagnet 16.

i-+, by energizing the coil 15 of the magnet 16, the amachia 17 is driven in the square position. Amathia 1
7 moves the head 18 of the printing wire 13 in the direction eζ147 of the arrow slope -20 against the spring force t of the spring 19, thereby driving the printing wheel 13 toward the platen 1o. The printing wheel 13 is printed in the direction of the paper jll vc + in FIG.
! i, and each printing wire 13 is individually provided m
It is selectively driven by the lj break 16 and the amatia 17, thereby performing dot printing.

FIG. 3 is a circuit diagram relating to the coil 15. A coil 15Kld switching transistor 21 is connected in series, and a supportable resistor 22 is connected in a row to this transistor 21. In parallel with the coil 15 is a half-wire body resistor 23 for preventing excessive back electromotive force from being generated. transistor 21
The 0 base is given a pulse for driving and braking the terminal 24〃S-3 wire 13. 0j variable resistance 22 is
(Continuously cutting the lid center cam 5, and narrowing the eccentric cam 5,
As the distance between the tip 13a of the printing wire 13 and the platen 10 becomes smaller, its resistance value increases.

FIG. 4 shows the time course of the current flowing through the coil 15 when a rectangular pulse is applied from the terminal 24 to the pace of the transistor 21. When the eccentric cam 5 is angularly positioned and the distance between the tip 4i 13a of the printing wire 13 and the platen 10 is set large, V, iiJ and resistance 22 (+11 is small. Therefore, the coil 1
The excitation current C of 5 is large as indicated by reference numeral 11. By setting the tip 13a of the printing wheel 13 close to the platen 10 by the eccentric cam 5, the resistance value of the 1J'' resistor 22 is greatly reduced. Therefore, the excitation current applied to the coil 15 becomes smaller as indicated by reference numeral 12. In this way, the tip 13a of the printing gloss 13 and the platen 10 are
As the J interval becomes smaller, the excitation power is changed smaller. Therefore, the operating speed of the printing wire 13 is reduced, and the return speed of the printing wire 13 is also reduced.

Therefore, it is possible to suppress rebound of the printing wire 13.

It is preferable that the distance between the tip 13a of the printing wire 13 and the platen 1O be short from the viewpoint of frequency followability. In the above-described embodiment 61, when the interval is small in this way, the excitation current is small, so that rebound can be suppressed and high print quality can be achieved.

In the above embodiment, the excitation current of the coil 15 is changed, but in other embodiments of the present invention, the voltage applied to the coil 15 may be changed instead of changing the excitation current. , or by other methods, I&/J 4d1. of the coil 15. 'All you have to do is change the four forces.

Effects As described above, according to the present invention, as the distance between the tip of the printing wire and the platen becomes smaller, the b'h magnetic power is changed smaller, so that the returning speed of the printing wire is controlled as the distance increases. As it becomes smaller, it becomes possible to keep it small. This makes it possible to completely improve printing quality.

[Brief explanation of the drawing]

FIG. 1 is a 1h11 hardened kenzan 1 diagram of an embodiment of the present invention, FIG. 2 is a diagram illustrating a simplified depiction of the printer head l, +1153 diagram is an electric circuit diagram connected to the coil 15, FIG. 4 pi is a diagram showing the excitation of the coil 15 and the intercostal course of the current. l... Printer head, 4... Follower, 5... Eccentric cam, lO... Platen, 13... Mark ¥ Tsuiya,
14...Core, 15...Coil, 16...Tun fd
Ladle, 17... Amathia, 18... Head, 19...
Spring, 21...transistor, 22...i+J friend resistance resistor valve μ [10 Nishikyo Kei Part 2 Figure 3 ゝ: 42 pieces Z Figure 8 day i 3

Claims (1)

[Claims] A printer head configured such that an electromagnet is excited to drive an amatia, and the amatia hits the head of a printing wire against the spring force of a spring to drive it toward a platen,
It is provided so that it can be moved toward or away from the platen, and is linked to the means for adjusting and setting the position of the printer head and the means for setting the position θM as the distance between the tip of the printing wire and the platen becomes smaller. A dot printer characterized in that it includes means for reducing excitation power to a small value.