JPS6161879A - Platen gap adjustor for dot printer - Google Patents

Abstract

PURPOSE:To enable a gap between a tip part of a printing head and a platen to be maintained with high accuracy, by a method wherein a piezoelectric element having one end fixed to a metallic fixing member for a printing head and the other end fixed to a part of a carrier is controlledly extended and contracted by impressing a controlled voltage thereon. CONSTITUTION:The carrier 13 is slidably supported by fixed guide shafts 11, 12, and one end of the piezoelectric element 16 is adhered to a side face of an upper part of the carrier 13. The metallic fixing member 17 for the printing head is adhered to the other end of the element 16. The printing head 14 is fixed on the top face of the member 17, with a gap DELTAg2 between the tip of the head 14 and the platen 6. Lead wires 19a, 19b from the element 16 are connected to a variable voltage device 18. Since the piezoelectric element 16 has a characteristic of expanding and contracting extremely rapidly in response to an impressed voltage, the gap DELTAg2 is narrowed when the impressed voltage is raised by operation the variable voltage device 18. Accordingly, the gap DELTAg2 can be minutely varied by vaying the impressed voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gap adjustment device for a dot impact printer.

[Prior art]

FIG. 1 shows a perspective view of a printing mechanism of a conventional dot printer. In Fig. 1, a carrier is connected by an (extended fixed guide shear 7) 1 and a guide shear 7) 2 rotatably held by both side frames to connect the two side frames (not shown) of the printer. 3 is parallel to the platen 6 and is shown so as to be able to reciprocate between both side frames. Furthermore, a print head 41 and a ribbon cassette 7 are mounted on the carrier 3.
The tip of the print head 4 is disposed opposite to the print paper 8 wound around the platen 6 so as to be close to the print paper 8 via the ink ribbon 9, and is configured to perform reciprocating motion. At this time, printing is performed by operating the printing wire at high speed from the tip of the printing head (according to a printing command).

In this printing operation, the total stroke of the printing wire is usually 0.5 to 0.6 mm, and in order to obtain the optimum printing quality (
It is preferable to set the gap between the tip of the print head and the print paper 8 so that a dot is printed at a stall position of 0.3 to 0.4 ms. Furthermore, the printing paper 8 may require a plurality of copies, and in this case, a gap PU at the tip of the printing head 4 is required depending on the thickness and thickness of the printing paper. For this reason, a gear gear adjustment device shown in FIG. 2 is generally employed. By holding the rotatable guide shaft 2 having an eccentric step of R■chiΔe at a specified angle, the carrier 3 is swung in the direction of the arrow around the fixed guide shaft 1, and the tip of the print head 4 and the platen are rotated. 6 to ensure appropriate print quality.

In this case, the guide shaft 2 needs to have a rotatable structure, so there needs to be some play in the support part with the side frame, and this play makes it difficult to secure an optimal gap between the tip of the print head 4 and the platen 6. It had the disadvantage of being difficult.

[Problems to be solved]

The dot printer platen gap adjustment device of the present invention solves the drawback that it is difficult to secure an appropriate gap due to the play between the conventional rotatable guide shaft and the side frame. f
! The purpose is to maintain high precision in the gap and gap with the leading edge of the paper, and to set the optimum gap and gap according to the total thickness of the printing paper, thereby ensuring high print quality.

[Structure of the invention]

The dot printer platen gap adjustment device of the present invention minimizes the play of the slide mechanism by fixing two guide shafts that guide the carrier, and one end is connected to the print head fixing metal fitting, and the other end is connected to the print head fixing metal fitting. The above-mentioned conventional problems can be solved by controlling a piezo element fixed to a part of the carrier to expand and contract using applied voltage, thereby maintaining the gap between the tip of the print head and the platen with high precision. This is to solve the problem.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a sectional view of a toy printer showing an embodiment of the present invention. The carrier 13 is a fixed guide shaft 11
．． The piezo element 16 is slidably held by the carrier 12, and one end of the piezo element 16 is bonded to the upper side surface of the carrier 13. A print head fixing fitting 17 is bonded to the other end of the piezo element 16. The print head 14 is fixed to the upper surface of the fixture 17 with a mounting screw 15, and the tip of the print head 14 maintains a gap between the platen 6 and the platen 6g2.

Lead wires 18a and 18b from the piezo 16 are connected to a variable voltage generator 19. Here, since the piezo element 16 has a characteristic of expanding and contracting extremely quickly in response to the applied voltage, when the applied voltage of the variable voltage generator 18 is increased, the piezo element 16 is displaced and the contact between the tip of the print head 14 and the platen 6 is increased. The gap Δg2 narrows. Thus, by varying the applied voltage, the gap Δg2 can be finely varied.

Based on the principle explained above, by setting an appropriate applied voltage by the operator, it is possible to maintain the gap at the tip of the print head that is optimal for the number of copies to be made, and it is possible to provide an impact type dot printer with high print quality.

〔Effect of the invention〕

As explained above, the platen gap adjustment device for a dot printer of the present invention includes a piezo element whose one end is fixed to a print head fixing fitting and the other end is fixed to a part of a carrier, and a control for controlling the displacement of the piezo element. Since the gap at the tip of the print head can be varied depending on the thickness of the printing paper, the gap at the tip of the print head can be set to an optimum value, and an impact dot printer with high print quality can be provided.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the printing mechanism of a conventional dot printer, Fig. 2 is a sectional view of the printing mechanism of a conventional dot printer, and Fig. 3 is a printing machine showing an embodiment of the present invention. It is a sectional view of a part. 11.12... Fixed guide shaft 13... Carrier 14... Print head 16... Piezo element 18... Variable voltage generator

Claims (1)

[Claims] A platen gap adjustment device for a dot printer, which includes a piezo element having one end fixed to a print head fixing fitting and the other end fixed to a part of a carrier, and a controller for controlling displacement of the piezo element.