JPS629032B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for assembling a printhead needle in a dot printer.

Generally, the print head of a dot printer has multiple needle guides fixed to a guide holder, and a plurality of curved needles with one end connected to a magnet are inserted into these needle guides so that they can slide freely while aligning the other end with the platen. This is what we are doing. It is inevitable that the first needle guide facing the platen is required to have the most accurate dimensions, and it is therefore troublesome to insert each needle toward the first needle guide. Furthermore, the magnets that drive each needle are generally arranged in a ring, and the degree of curvature of each needle varies slightly between the rear, center, and tip portions on the magnet side. Therefore, even if the arrangement of each needle guide and the degree of curvature of the needle are determined with emphasis on the insertion of the needle into each needle guide, the linearity of the needle is maintained between the platen and the first needle guide. Not necessarily. If this straightness is inhibited, clear printing will not be possible, and if the arrangement of each needle guide and the degree of curvature of the needle are determined with priority given to straightness, it will be difficult to assemble the needles into each needle guide. It has some drawbacks.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for assembling a needle of a printing head in a dot printer, which makes it possible to easily insert the needle.

In this invention, a plurality of needle guides that curve and hold a plurality of needles driven by magnets so that their tips are aligned with a platen are attached to a guide holder, and among these needle guides, A first needle guide facing the platen is fixed, and at least one of the needle guides other than the first needle guide is provided in a position adjustable manner,
All needles are inserted by positioning this needle guide in a curved position where the needles are smoothly inserted into the first needle guide, and after the needle insertion, the needles are removed from the first needle guide. The needle guide is characterized in that the adjustable needle guide is moved to a position that improves the straightness of the protrusion. Therefore, when inserting the needle guide, the positionally adjustable needle guide is in a position where the needle can be inserted into the first needle guide, so the insertion is easy, and furthermore, after insertion, the positionally adjustable needle guide is in a position where the needle can be inserted into the first needle guide. By moving the needle guide, the needle can be ejected from the first needle guide with good straightness.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. Reference numeral 1 shown in FIG. 1 is a guide holder having a mounting surface 2 for mounting on a yoke, which will be described later, and a protrusion 3 that protrudes toward a platen (not shown). This protrusion 3 has a plurality of needle guides 4,
Grooves 8, 9, 10, and 11 for holding 5, 6, and 7 are formed. The grooves 8, 10, 11 are for fixedly supporting the needle guides 4, 6, 7,
The groove 9 has a length that supports the second needle guide 5 next to the first needle guide 4 facing the platen so as to be slidable toward and away from the first needle guide 4. The needle block A is assembled by inserting a plurality of needles 12 made of steel wire through these needle guides 5, 6, and 7. Each needle 1
Caps 13 are fixed to the rear ends of the needles 2, and a needle spring 14, which is a leaf spring that engages with these caps 13 and urges the needles 12 away from the platen, is a support portion that rises from the mounting surface 2. It has been fixed at 15. The second needle guide 5 slides with a stroke between a position in which it approaches the first needle guide 4 and a position in which it moves away from the first needle guide 4.

Next, the magnetic block B will be explained based on FIG. First, the yoke 16 is provided.
A plurality of magnets 17 are attached to this yoke 16.
Attach the stopper 19 to the armature guide 18 provided on the yoke 16, and install the armature spring 21 that biases the armature 20 held by the armature guide 18 against the attraction force of the magnet 17. Place the attached lid 22 on the yoke 1
6, thereby assembling the magnetic block B.

In such a configuration, the needle block A
When assembling, a plurality of needles 12 are inserted into each needle guide 5, 6, 7. In this state, the needle 12 is urged backward by the needle spring 14, but by positioning the second needle guide 5 in the rear position RO as shown in FIG. 1, the needle spring 14 returns to its free state. Even when the needle 12 is pulled upward, the second needle guide 5 holds the tip of the needle 12 with sufficient margin.

In addition, in the assembly process of magnetic block B, the armature 20 and stopper 19 are assembled as follows.
This is done regardless of the needle 12 being biased away from the platen, and the individual armature 20
The lid 22 can be easily attached to the yoke 16 without pressing the stopper 19.

Next, screws 24 are passed through the mounting holes 23 formed in the mounting surface 2 of the guide holder 1, and these screws 24 are
Needle block A and magnetic block B are connected by screwing them into yoke 16. At this time, when the second needle guide 5 is located in the forward position as shown in FIG. 4a, the first needle guide 4 and the third needle guide 6
The degree of curvature between the needle 12 and
can be inserted smoothly into the first needle guide 4. However, in this state, the needle 12 deviates from the center line CL as shown by the arrow L in FIG. Gather and secure with adhesive. In this state, the degree of curvature of the needle 12 between the second needle guide 5 and the third needle guide 6 is increased, but the distance from the second needle guide 5 to the platen via the first needle guide 4 is indicated by the arrow. It coincides with the center line CL as shown in C. That is, the straightness of the needle 12 when it pops out from the first needle guide 4 is improved, and clear printing can be performed.

Next, a second embodiment of the present invention will be explained based on FIGS. 5 and 6. The same reference numerals are used for the same parts as those described in the previous embodiment, and the description thereof will be omitted. In this embodiment, the third needle guide 6 is supported so as to be movable between front and rear positions.

Therefore, when the third needle guide 6 is located in the rear position as shown in FIG. However, the degree of curvature in the front from the third needle guide 6 gradually weakens, and from the second needle guide 5 to the first needle guide 4, the center line is almost the same.
Close to CL. Therefore, the operation of inserting the needle 12 into the first needle guide 4 can be performed smoothly. However, by moving the third needle guide 6 to the rear position, the needle 12
When the degree of curvature of the rear part of the needle 12 is increased, an upward force is generated at the front part of the needle 12 as a reaction force, and the upward tendency becomes larger as the position approaches the front part. As a result, when the needle 12 is slid forward, the direction of the needle 12 between the first needle guide 4 and the platen is deviated from the center line CL, and the arrow U
facing the direction. Therefore, after assembly, the third needle guide 6 is brought to the front position and fixed with adhesive as shown in FIG. 6b.
In this state, the degree of curvature of the needle 12 between the third needle guide 6 and the fourth needle guide 7 is weakened, and the change in the degree of curvature of the needle 12 is smooth over the entire needle. While reaching the first needle guide 4, it shows a tendency to extend slightly downward toward the front, but from the first needle guide 4 to the platen, it coincides with the center line CL as shown by arrow C. Therefore, clear printing can be performed.

Since this invention is constructed as described above, by sliding the needle guide during assembly, the degree of curvature of the needle can be determined and the needle can be smoothly inserted toward the first needle guide. To make it possible to adjust the position of the needle guide and the degree of curvature of the needle, emphasizing the straightness of the needle from one needle guide to the platen, and therefore to simplify assembly and to print clearly. It has the following effects:

[Brief explanation of the drawing]

Fig. 1 is a plan view of a needle block showing a first embodiment of the invention, Fig. 2 is a horizontal sectional view of the magnetic block, and Fig. 3 is a partially sectional view showing the entire assembly state. FIG. 4 is an explanatory diagram showing the curved state of the needle; FIG. 5 is a partially sectional plan view showing the entire assembled state of the second embodiment of the present invention; FIG. The figure is an explanatory view showing the curved state of the needle. 1...Guide holder, 4...Second needle guide, 5-7...Needle guide, 12...Needle,
17...Magnet.

Claims (1)

[Claims] 1. Attach to the guide holder a plurality of needle guides that curve and hold a plurality of needles driven by magnets so that their tips are aligned with the platen, and among these needle guides, the one facing the platen is A first needle guide is fixed, and at least one of the needle guides other than the first needle guide is provided so as to be adjustable in position, and the needle is smoothly inserted into the first needle guide. The needle is inserted into the first needle guide by positioning the needle in a curved position, and after inserting the needle, the needle is placed in a position where the straightness of the needle when ejecting from the first needle guide is improved. A method for assembling a print head needle in a dot printer, characterized in that the position-adjustable needle guide is moved and fixed.