JPS62193839A - Printing line head of dot matrix line printer - Google Patents

Abstract

PURPOSE:To optimize the setting of a distance between an upper and a lower printing mechanism by providing an eccentric cam which is interlocked to adjust the clearance between a printing pin and a platen between two printing mechanisms. CONSTITUTION:When a platen gap adjustment lever 10 is actuated, an eccentric cam 14 rotates, causing a connection plate 11 and a platen 12 to move to a printing line head direction and subsequently setting a platen gap. At the same time, an eccentric cam 7 rotates through a shaft 9 connected to the platen gap adjustment lever 10, and an upper and a lower printing mechanism are guided by a back plate 13 and a tension spring 8. These mechanisms move vertically maintaining contact with the eccentric cam 7, thus setting the clearance between the upper and lower printing mechanisms at an optimum position. Consequently enlargement of the platen gap can be prevented and thereby the movement of the tip of a printing pin 5 be stopped, which always maintains the clearance between upper and lower dots.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a printing line head for a dot matrix line printer, and in particular to a printing line head for a dot matrix line printer in which the printing mechanism is stacked in two stages by adjusting the platen cap. Regarding printing line heads that improve quality.

[Conventional technology]

In a conventional printing line head of this type, as shown in FIG. 4, a permanent magnet 1 and yokes 2 and 3 are respectively sandwiched between the permanent magnet 1 and a printing hammer 4, which is disposed opposite to the yoke 3. The printing hammer 4 was composed of a cantilever leaf spring, one end of which was fixed to the yoke 2, and a printing pin 5 for printing dots was connected to the free end. A coil 6 was wound around the yoke 3 for activating the printing machine 4. The print mark 4 is usually attracted to the yoke 3 by the magnetic force of the permanent magnet 1, as shown by the solid line in Fig. 4, and when a current is passed through the coil 6 as required, the magnetic flux of the permanent magnet 1 increases. was canceled and left the yoke 3, moving as shown by the broken line in FIG. At this time, the printing pin 5tiSt was moved to print dots on the paper via an ink ribbon (not shown).

[Problems to be solved]

In the conventional printing line head described above, I! between the printing pin 5 and the platen (not shown). 1 (hereinafter referred to as the platen gap) is set wide or the paper is thin, the printing hammer 4 moves to the position shown by the dashed line, and the printing pin 5 moves by 82 to print dots in the same way. Was. Since the amount of movement of the printing pin 5 was 82, the position of the tip of the printing pin 5 was different by d from the case where the amount of movement of the printing pin 5 was Sl. Therefore, when the same paper is used, if the platen gap setting is changed, the position of the printed dot changes by d.

In other words, when the setting of the platen gap is changed, the movement t of the upper and lower printing pins 5 becomes Sl, and the interval between the upper and lower printed dots becomes (D+2d) as shown in the figure, which is the case when the platen gap is normal. There was a drawback that the distance between the upper and lower dots was increased by 2d. Furthermore, there was a drawback that high printing quality could not be maintained.

[Means for solving problems]

In order to solve the above-mentioned conventional problems, the present invention provides a printing line head for a dot matrix line printer in which two printing mechanisms are stacked in two stages, upper and lower, in a direction perpendicular to the swinging direction. an eccentric cam provided between the printing mechanisms and interlocked with a gap adjustment mechanism between the printing pin and the platen; a tensicon spring that always maintains the two printing mechanisms and the eccentric cam in contact;
The present invention provides a printing line head for a dot matrix line printer, characterized in that it includes a back plate that restricts the movement of two printing mechanisms in the front, back, right, and left directions.

〔Example〕

Next, the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an embodiment of a printing line head of a dot matrix line printer according to the present invention. Second
The figure is a partial side view of the embodiment of FIG. 1. FIG. 3 is a perspective view showing another embodiment of the printing line head of the dot matrix line printer of the present invention.

First, the embodiment of the present invention shown in FIG. 1 will be explained in detail.

A permanent magnet 1 is sandwiched between a yoke 2.3, and a printing mark 4 is arranged opposite the yoke 3.

The printing hammer 4 has one end fixed to the yoke 2 by a cantilever spring, and a printing pin 5 for printing dots is connected to the free end. A coil 6 is wound around the yoke 3 to operate the printing printer 4.

A printing mechanism having this configuration is arranged vertically symmetrically via an eccentric cam 7. The eccentric cam 7 is maintained in normal pressure contact with the yokes 3 of the upper and lower printing mechanisms by a tension spring 8.

A shaft 9 of the eccentric cam 7 is connected to a platen gap adjustment lever 10. Platen gap adjustment lever 10
Vc is configured such that the platen 12 is operated by a connection plate 11 to which an eccentric cam 14 is attached and which is in contact with the eccentric cam 14 and to which a platen 12 is attached. Father, on the back of the printing line head there is a back plate that regulates the movement of the upper and lower printing mechanisms in the front, back, left and right directions.
13 is provided so that the upper and lower printing mechanisms can only move in the vertical direction (paper feeding direction).

Next, the operation will be explained. The operation of the printing mechanism is the same as that of a conventional printing line head, so a description thereof will be omitted.

When the platen gap adjustment lever 10 is operated, the eccentric cam 14 rotates, and the platen 12 approaches or moves away from the print line head via the connection plate 11, thereby setting the platen gap. At the same time, the eccentric cam 7 rotates through the shaft 9 connected to the platen gear young adjustment lever 10, and the upper and lower printing mechanisms are guided by the back plate 13 and the tension spring 8 to prevent contact with the eccentric cam 7. The gap between the upper and lower printing mechanisms is set to the optimum position for the platen gap set at that time.

Therefore, the platen gap can be prevented from expanding from 81 to S2, and the tip of the printing pin 5 can be prevented from moving by d (see FIG. 2), so that the distance between the upper and lower dots can be maintained at all times.

Further, the embodiment of the present invention shown in FIG. 3 will be described in detail.

In the embodiment shown in FIG. 3, at least the connection play 11 and the eccentric cam 14 are removed from the embodiment shown in FIG. Therefore, when the platen gap adjustment lever 10 is operated, the eccentric cam 7 rotates via the shaft 9 connected to the platen gap adjustment lever 10, and the upper and lower printing mechanisms are guided by the back plate 11 and the tension spring 8, and the eccentric cam 7 is rotated through the shaft 9 connected to the platen gap adjustment lever 10. While maintaining contact with the platen gap, the printing mechanism moves in the vertical direction (paper feeding direction) to become wider or narrower, and the interval between the upper and lower printing mechanisms is set to the optimal position for the platen gap set at that time.

〔Effect of the invention〕

As explained above, the present invention provides an eccentric cam that is operated in conjunction with a platen gap adjustment mechanism or via a platen gap adjustment lever and a shaft between the upper and lower printing mechanisms in a printing line head configured by stacking printing mechanisms in two stages. Since the distance between the upper and lower printing mechanisms is automatically set optimally with respect to the platen gap, it is possible to provide a dot matrix line printer with good printing quality regardless of the platen gap.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the printing line head of the dot matrix line printer of the present invention, FIG. 2 is a side view of the same part, and FIG. FIG. 4 is a side sectional view of a conventional printing line head. 1... Permanent magnet 2... Yoke 3... Yoke 4... Printing no.1 5... Printing pin 6... Coil 7... Eccentric cam
8... Tension spring 9... Shaft 10.
...Platen gap adjustment lever 11...Connector 1
platen 12...platen 13...back plate 14...eccentric cam 15...side frame agent patent attorney Mura 1) Miki Yuzono 2 diagram

Claims (1)

[Claims] In the printing line head of a dot matrix line printer, which is constructed by stacking two printing mechanisms in two stages, upper and lower, in a direction perpendicular to the swinging direction, the printing line head is provided between the two printing mechanisms, and is connected between the printing pin and the platen. An eccentric cam interlocked with a gap adjustment mechanism, a tension spring that always maintains the two printing mechanisms and the eccentric cam in contact, and a back plate that restricts the movement of the two printing mechanisms in the front-rear and left-right directions. A printing line head for a dot matrix line printer characterized by comprising: