JPS6143574A - Dot printer - Google Patents

Abstract

PURPOSE:To enable relative positions of needles of a plurality of dot printing heads to be determined easily and accurately, by providing a guide frame with positioning projections and providing a needle guide with positioning holes to be engaged with the projections. CONSTITUTION:A tip part of the guide frame 7 is provided with a slit 14, the positioning projections 15 located at both ends of the slit 14, and an annular groove 16 and a recessed part 17 which surround the slit 14. The recessed part 17 is provided with projected parts 18 on the inside surface thereof, the distance between each opposed pair of the projected parts 18 is so set that the needle guide 19 is fitted thereto with a play. Fitting screws 13 are untightened, a thickness gage with a predetermined thickness is inserted between the tip of each of the guide frames 7 and a platen 2, and the screws 13 are tightened while pressing the dot printing heads 5, 6 against the platen 2 side and the reference surface 11 side. Accordingly, the gap between each needle 20 and the platen 2 is adjusted, and the fitting spacing of the heads 5, 6 and the rectangularity of the centers of the heads 5, 6 to the platen 2 are determined by the reference surfaces 11.

Description

[Detailed description of the invention] Technical field of invention This invention relates to a dot printer.

Technical background of the invention and its problems In dot printers, the number of needles is increased in order to perform high-speed printing or high-density printing, but in order to reduce costs, multiple dot printer heads with a small number of needles are lined up to form a single printer. There are dot printers mounted on carriers.

As a result, when performing high-speed printing, the characters to be printed are shared between each dot printer, and when performing high-density printing, the mounting height of the dot printer head is determined with a difference of 1/2 of the needle arrangement pitch, and Each character is printed using several dot printer heads. In any case, it is necessary to accurately determine the mounting positions of the plurality of dot printer heads. At the same time, the position of the needle guide must be accurately determined for each dot printer head.

Conventionally, the needle guide is fitted and glued to the tip of the guide frame of the dot print head, but if the clearance at the fitting part is large, the needle guide moves before the adhesive hardens, causing the needle to be attached to each dot print head. The positions are different, resulting in uneven printing. There are some devices in which a protrusion is formed on the edge of the opening at the tip of the guide frame in order to reduce the clearance between the guide frame and the needle guide.

Since the precision of the outer diameter of the needle guide, the dimensions of the guide frame, and the positional dimensions of the needle relative to the periphery of the needle guide must be increased, manufacturing is difficult and the cost is high. In the case where a needle hole is formed at the tip of the guide frame to allow the needle to pass directly through the guide frame, the selection range of materials for the guide frame is narrow in terms of molding, the durability of the needle hole is poor, and it is difficult to polish the tip of the needle.

OBJECTS OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to provide a dot printer that can accurately and easily determine the relative positions of needles between a plurality of dot printer heads.

SUMMARY OF THE INVENTION This invention has a plurality of dot printer heads mounted on one carrier, in which the mounting interval of the dot printer heads is fixed at a constant interval using a reference surface formed on the carrier, and the mounting surface formed on the carrier allows the dot printer to be mounted on a single carrier. The vertical dimensions of the heads are set constant, and the guide frame of each dot printer head can be formed using a common mold.In particular, the guide frame is provided with a positioning protrusion, and the positioning hole that engages with the positioning protrusion is formed using a needle. By forming into a guide.

Accurately positioning the needle guide with respect to the guide frame and thus allowing the relative position of the needles between individual dot print heads to be accurately and easily determined, thereby increasing the tolerance of the needle hole relative to the periphery of the needle guide. Therefore, the structure is such that it can be easily manufactured.

Examples of the invention An embodiment of the present invention will be described based on the drawings.

1 is a carrier. The carrier 1 is slidably held by a carrier shaft 3 and a guide 4 parallel to the platen 2. The guide frames 7 of the two dot printer heads 5 and 6 mounted on this carrier 1 are formed by a common mold, and a flange 8 having a mounting hole 9 is formed on one side of these guide frames 7. has been done. The carrier 1 is formed with two mounting surfaces 10 on which the bottom surface of the flange 7 is placed, and two reference surfaces 11 that abut on one side of the guide frame 7. A screw hole 12 facing the mounting hole 9 is formed in the mounting surface 10.
The dot printer heads 5 and 6 are fixed to the carrier 1 by screwing the mounting screws 13 into the carrier 1.

As shown in FIGS. 3 to 5, the guide frame 7 has a slit 14 at its tip, a positioning protrusion 15 located at both ends of the slit 14, an annular groove 16 surrounding the slit 14, and a recess 17. is formed. A protrusion 18 is formed on the inner surface of this recess 17.
8 is set to a size that allows the needle guide 19 to fit with some play. The needle guide 19 is formed with nine needle holes 21 through which the needles 20 pass and two positioning holes 22 equal to these needle holes 21. These positioning protrusions 15 and positioning holes 22 have the same pitch and approximately the same diameter.

Then, the positioning protrusion 15 and the positioning hole 22 are engaged with each other. The needle guide 19 is fixed to the recess 17 with adhesive.

In such a configuration, loosen the mounting screw 13.

A thickness gauge of a predetermined thickness is inserted between the tip of the guide frame 7 and the platen 2, and the dot printer head 5 is
, 6 against the platen 2 side and the reference surface 11 side, and tighten the mounting screw 13. As a result, the gap between the needle 20 and the platen 2 is adjusted, and the mounting interval of the two dot printer heads 5, 6 and the perpendicularity of the centers of the dot printer heads 5, 6 with respect to the platen 2 are determined by the reference plane 11. The attachment position of the needle guide 19 to the guide frame 7 is between the positioning protrusion 15 and the positioning hole 2.
2, and since the guide frames 7 of the two dot printer heads 5 and 6 are also molded by a common mold, there is no dimensional difference. Therefore, the relative positional relationship between the needles 20 of the two dot printer heads 5 and 6 is accurately determined, and it is possible to print in a clean and undisturbed state. By matching the heights of the two mounting surfaces 10 formed on the carrier l, the characters to be printed can be shared between the dot printer heads 5 and 6, and high-speed printing can be achieved. By setting the height of the mounting surface 10 at a difference of 1/2 of the arrangement pinch of the needles 20, one character can be divided into two parts and printed by the dot printer heads 5 and 6, resulting in high-density printing. You can get the status. Any one can be selected freely, and in this case, the variation in height of the two mounting surfaces 10 can be kept within a small tolerance range by molding.

Further, the needle guide 19 is connected to the recess 1 of the guide frame 7.
7 with a rough dimensional relationship, it is not necessary to strictly determine the position of the needle hole 21 with respect to the outer periphery of the needle guide 19.

The pitch of the needle holes 21 has conventionally been manufactured with an accuracy of ±0.01+m+, and it is easy to determine the diameter and pitch of the positioning holes 22 with the same accuracy.

Therefore, manufacturing can be performed easily.

Note that as a means for providing positioning projections on the guide frame 7, holes may be formed at the positions of the positioning projections 15, and bottles may be inserted into these holes.

These pins may be removed after the needle guide 19 is positioned and bonded. Further, since the adhesive for fixing the needle guide 19 can escape into the four corners of the recess 17 or into the groove 16, it does not protrude into unnecessary areas.

Effects of the Invention Since the present invention is configured as described above, it is possible to accurately determine the arrangement of a plurality of dot printer heads using the reference surface and the mounting surface formed on the carrier, and furthermore, the installation of the needle guide to the guide frame can be easily determined. The dimensions can be determined accurately by the engagement between the positioning holes and the positioning protrusions, and therefore, the alignment of the needles between multiple dot printer heads can be determined accurately to obtain neatly aligned printing results. Both the guide frame and the guide frame can be molded with uniform dimensions using the same mold, and the positioning hole of the needle guide can be easily formed with the same dimensional accuracy as the needle hole, and the needle hole and positioning with respect to the periphery of the needle guide can be easily formed with the same dimensional accuracy. The dimensions and positions of the holes can also be made with rough tolerances, which has the advantage of making it easier to manufacture parts and assemble them.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a plan view, FIG. 2 is a partially cutaway front view, FIG. 3 is a front view of the guide frame, and FIG. 4 is a longitudinal cross-section of the guide frame. FIG. 5 is a side view, FIG. 5 is a horizontal sectional view of the guide frame, FIG. 6 is an enlarged front view showing the attachment and state of the needle guide, and FIG. 7 is a central sectional view of FIG. 6. DESCRIPTION OF SYMBOLS 1... Carrier, 2... Platen, 5, 6... Dot printer head, 7... Guide frame, 10...
... Placement surface, 11... Reference surface, 15... Positioning protrusion, 19... Needle guide, 20... Needle,
21... Needle hole, 22... Positioning hole

Claims (1)

[Claims] A carrier is provided with a plurality of dot printer heads having a guide frame through which a plurality of needles are inserted, and a plurality of reference planes are provided on the carrier, which abut one side of the dot printer heads and define attachment intervals of these dot printer heads. and a mounting surface that determines the mounting height of these dot printer heads, and a positioning hole is formed in a needle guide in which a needle hole is formed to align and slidably hold the tips of the needles in a straight line. With,
A dot printer characterized in that a positioning protrusion that matches the positioning hole is provided at the tip of the guide frame, and the needle guide is fixed to the guide frame by engaging the positioning hole and the positioning protrusion.