JP2000335042A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate generation of noise due to variation in the contact position of an elongated hole and a pin between printing time and sheet feeding time. SOLUTION: The positioning pin 9 of a frame 1 and the elongated positioning hole 17 of a supporting plate 15 are formed at such positions as a force F1 acts from a spring 13 to a print head 11 orthogonally to the surface thereof when the pin 9 is located at the side end part of the head fixing face 15a on the inner side face of the elongated hole 17. Since the force F1 is orthogonal to the surface of the print head 11, drag F2 of a platen 3 is parallel with the force F1. Since the contact position of the elongated hole 17 and the pin 9 is not different when printing is carried out and when a sheet is fed even if a force F4 is applied through rotation of the platen 3 when a sheet is fed, noise is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer and a plotter generally used for OA equipment such as an analytical instrument and a facsimile, and more particularly to a parallel printer and a plotter provided with a long thermal print head. Here, the parallel type refers to a type in which a linear thermal print head extending in a direction perpendicular to the transport direction of the thermal paper is fixed.

[0002]

2. Description of the Related Art FIG. 1 is a schematic structural view showing the periphery of a print head of a conventional printer.
(B) is a cross-sectional view at the AA 'position in (A), and (C) is a cross-sectional view showing the positional relationship among the platen, the long thermal print head, the support plate, the long hole, and the positioning pin in (B). is there. A platen 3 is rotatably supported by the frame 1. The platen 3 is made of, for example, rubber, serves as a cushion during printing, and transports the thermal paper during paper feeding (paper feeding).

[0003] A support plate 5 is rotatably mounted on the frame 1. The support plate 5 is rotatably and displaceably supported on the frame 1 by fitting positioning long holes 7 provided at both ends in the longitudinal direction with positioning pins 9 formed on the frame 1. . The elongated hole 7 is formed with a length in a direction orthogonal to the head fixing surface 5 a of the support plate 5. The positioning pin 9 is formed with a diameter slightly smaller than the dimension of the long hole 7 in the short direction. A long thermal print head 11 is provided on the head fixing surface 5a of the support plate 5.
Is attached.

A print head pressing spring 13 is provided between the frame 1 and the support plate 5. The spring 13 is inserted in a compressed state, and urges the support plate 5 in a direction of rotating the support plate 5 toward the platen 3, that is, a direction of pressing the print head 11 mounted on the support plate 5 against the platen 3. The positioning pin 9 is formed at a position immediately below the contact point between the platen 3 and the print head 11, that is, in a plane including the surface of the print head 11, and the elongated hole 7 of the support plate 5 The line connecting the contact point with the head 11 and the positioning pin 9 and the support plate 5
When the head fixing surface 5a is parallel, the positioning pin 9 is formed at the center of the elongated hole 7 ((C)).
reference). The force of the spring 13 is applied in a direction orthogonal to a line connecting the contact point between the platen 3 and the print head 11 and the positioning pin 9, and the end of the positioning pin 9 and the inner surface of the elongated hole 7 on the head fixing surface 5 a side. Is in contact with Therefore, the contact point between the platen 3 and the print head 11 and the positioning pin 9
Is not parallel to the head fixing surface 5a of the support plate 5 (see (B)).

FIG. 2 is a top view showing the operation of the positioning slot. In the manufacturing process of the platen 3, the platen 3 may not be formed in a true cylindrical shape, but may be formed in a truncated conical shape as shown in (A) and (B). If such a platen 3 is mounted on the printer, if the support plate 5 is
If the platen 3 is supported by a circular positioning hole formed in the support plate 5 corresponding to the positioning pin 9, a gap is formed between the platen 3 and the print head 11 as shown in FIG. On the left side of the drawing, the print head 11 and the thermal paper do not adhere to each other, and the print is blurred. Therefore, as shown in FIG. 1, by forming a positioning hole for supporting the support plate 5 on the frame 1 in an elongated hole, as shown in FIG.
Print head 11 corresponding to the angle of the surface of platen 3
Is changed, and the platen 3 and the print head come into close contact with each other, so that the print density can be made uniform.

[0006]

FIGS. 3A and 3B are diagrams showing the relationship between the forces acting on the support plate and the print head in the printer shown in FIG.
(A) At the time of printing, a force F1 from a spring 13 and a drag F2 from a platen 3 are applied to the print head 11 via the support plate 5. Since the force F1 and the drag F2 are not parallel, the support plate 5 to which the print head 11 is fixed is
, A force F3 acts on the positioning slot 7 and the positioning pin 9
Contact at a position a surrounded by a broken line.

(B) At the time of paper feeding, the print head 1
1, a force F4 is applied by rotation of the platen 3. Force F
4, the support plate 5 is moved in the opposite direction to the force F3,
The positioning slot 7 and the positioning pin 9 come into contact at a position b surrounded by a broken line. Thus, at the time of printing and paper feeding,
The position where the positioning long hole 7 and the positioning pin 9 contact is different. Therefore, when printing and paper feeding are repeated during the operation of the printer, the support plate 5 is rattled. For example, if printing and paper feeding are repeated every 10 milliseconds, a noise of 100 Hz is generated. Accordingly, it is an object of the present invention to eliminate the occurrence of noise due to a change in the contact position between a long hole and a pin between printing and paper feeding.

[0008]

According to the present invention, there is provided a platen extending in the longitudinal direction of a thermal print head, facing a surface of a long thermal print head fixed to a support plate, and a back side of the support plate. A spring is provided for urging the thermal print head in the direction of pressing the plate toward the platen, and the support plate is rotated with respect to the frame by fitting pins at both ends in the longitudinal direction with elongated holes extending in the urging direction of the spring. A parallel printer supported movably and displaceably, wherein the position of the pin and the slot is determined so that the contact position between the pin and the slot becomes the same at the time of printing and at the time of feeding. is there.

The positions of the pins and the long holes are determined so that the contact positions between the pins and the long holes are the same at the time of printing and at the time of paper feeding. The contact position of the hole does not change, so that it is possible to suppress the generation of noise due to the change of the contact position between the elongated hole and the pin.

[0010]

4A and 4B are schematic structural views showing the periphery of a print head according to one embodiment. FIG. 4A is a top view, and FIG.
FIG. 4 is a cross-sectional view taken along line AA ′ of FIG. The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. A platen 3 and a support plate 15 are rotatably mounted on the frame 1, and a linear thermal print head 11 is mounted on a head fixing surface 15 a of the support plate 15, and a print head is provided between the frame 1 and the support plate 15. A pressing spring 13 is provided. The support plate 15 is rotatably and displaceably supported on the frame 1 by fitting positioning long holes 17 provided at both ends in the longitudinal direction with positioning pins 9 formed on the frame 1. .

The positioning pin 9 is formed at a position just below the contact point between the platen 3 and the print head 11, that is, in a plane including the surface of the print head 11, and the elongated hole 17 of the support plate 15 is And print head 1
1 and the line connecting the contact point with the positioning pin 9 and the support plate 15
When the head fixing surfaces 15a are parallel to each other, the positioning pin 9 is formed at an end of the inner wall surface of the elongated hole 17 on the side of the head fixing surface 15a (the left end position of the elongated hole 17 in the figure) ( (B)).

The force F1 from the spring 13 acting on the print head 11 is orthogonal to the head fixing surface 15a of the support plate 15,
The surface of the print head 11 that is in contact with the platen 3 is also perpendicular to the surface. At this time, the drag F2 from the platen 3 to the print head 11 becomes parallel to the force F1. for that reason,
The force F3 as shown in FIG. 3 is not generated, and even when the force F4 is applied by the rotation of the platen 3 at the time of paper feeding, the contact position between the slot 17 and the positioning pin 9 at the time of printing and paper feeding. Are not different, and no noise is generated.

In this embodiment, the support plate is provided with a positioning slot so that the force F1 from the print head pressing spring acting on the print head is orthogonal to the surface of the print head on the side in contact with the platen, and the frame is positioned. Although the pins are provided, the present invention is not limited to this. The positioning pins may be provided on the support plate, and the positioning slots may be provided on the frame. Further, the positioning slot and the positioning pin may be formed at positions where the surface of the print head is inclined toward the platen. In this case, a force acts on the print head and the support plate in the tilt direction of the print head by a spring, and the force acts in the same direction as the force acting on the print head and the support plate by rotation of the platen. The positioning pins do not rattle.

[0014]

According to the parallel printer of the present invention, the position of the pin and the slot is determined so that the contact position between the pin and the slot becomes the same at the time of printing and at the time of feeding. Is repeated, the contact position between the pin and the slot does not change,
Generation of noise can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a print head periphery of a conventional printer, (A) is a top view, (B) is a cross-sectional view at AA ′ position of (A), and (C) is (B). 4 is a cross-sectional view illustrating a positional relationship among a platen, a long thermal print head, a support plate, a long hole, and a positioning pin in FIG.

FIG. 2 is a top view showing the operation of a positioning slot.

FIGS. 3A and 3B are diagrams illustrating a relationship between forces applied to a support plate and a print head during printing and FIG.

FIGS. 4A and 4B are schematic configuration diagrams illustrating the periphery of a print head according to an embodiment, where FIG. 4A is a top view and FIG.
It is sectional drawing in the A 'position.

[Explanation of symbols]

 Reference Signs List 1 frame 3 platen 9 positioning pin 11 parallel type thermal print head 13 print head pressing spring 15 support plate 15a head fixing surface 17 positioning long hole

Claims (1)

[Claims] 1. A platen extending in the longitudinal direction of a thermal print head is disposed opposite a surface of a long thermal print head fixed to a support plate, and the thermal print head is disposed on the platen side on the back side of the support plate. A spring for urging in the pressing direction is provided, and the support plate is rotatable and displaceable with respect to the main body frame by fitting a pin and an elongated hole extending in the urging direction of the spring at both ends in the longitudinal direction. In the parallel printer which is supported, the position of the pin and the slot is determined so that the contact position between the pin and the slot is the same at the time of printing and at the time of feeding. Characterized printer.