JPS6021281A - Printing apparatus - Google Patents

Abstract

PURPOSE:To make it possible to maintain driving accuracy, by imparting rotation energizing force against the rotation of a carriage shaft to one end of a slider guided along the spiral groove of the carriage shaft by an energizing spring. CONSTITUTION:A carriage shaft is rotated through a flat belt and pulleys by driving a motor and one end part 30 of a slider loosely inlaid with a spiral groove 27 is slid while guided along said groove 27 to slide a carriage. Herein, the H-cut part 31 of the slider 28 is grasped by a U-shaped spring 32 and receives energizing force in (c)- and (d)-directions to be apt to rotate to an (e)- direction and the gap of the width (w) of the groove 27 and the thickness (t) of the end part 30 comes to zero. By this mechanism, the carriage reciprocally moves along a platen by the rotation of the shaft and driving accuracy is enhanced while the deterioration in accuracy due to abrasion is eleminated and it is made unnecessary to enhance processing accuracy to a necessary extent or more.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printing device that prints on paper on a platen by reciprocating a carrier carrying a print head along a platen.

Conventional configurations and their problems In recent years, high-definition CRT color displays have appeared in response to the increasing functionality of personal computers (word processing functions, graphics functions, etc.), and they are also being used in printers and typewriters used as output devices. Similarly, the demand for high-density printing, graphic printing, and three-primary color overlapping printing has increased. High precision is naturally required for the gear ridge drive devices of printers and typewriters, and it is no longer possible to adequately support graphic printing and three-primary color overlapping printing. must not. However, the gear ridge drive device of conventional printers.

0) When wire lower 1 is used (2) When a flat belt and multiple gears are used (3) When a screw shaft is used, but in the case of (1), when the wire lobe is pulled In addition to the complicated winding work around the drive drum, the wire rope expands and contracts over time, resulting in a deterioration in the driving accuracy of the bearing.

In the case of item (2), because multiple gears are used in combination, backlash between the gears or elongation of the flat belt due to environmental changes occurs, making it impossible to achieve high precision drive of the carriage. This caused problems such as printing misalignment.

Furthermore, the case of item (3) will be explained based on the drawings.

Here, FIG. 1 is an exploded perspective view showing an example of a conventional gear ridge drive device, in which a print head 1 is mounted on a gear ridge 2 and guided by a gear ridge shaft 3 arranged parallel to the platen axis. It reciprocates and prints on the paper 5 wound around the platen 4 via the ink ribbon 6. On the other hand, a nut part 8 on which a plurality of steel balls 7 slide is fitted into the gear ridge 2 in the direction of arrow A, and the steel balls 7 are guided into a spiral groove 9 formed in the gear ridge shaft 3 and slide. , the gear ridge 2 is reciprocated along the platen 4 by the rotation of the gear ridge shaft 3.

In the carriage drive system configured as described above, the gap between the groove 9 and the steel ball 7 affects the feeding accuracy of the carriage 2. However, it was extremely expensive because it was hardened to prevent wear due to high-precision fitting and friction, and precision-machined to eliminate the gap between the groove 9 and the steel ball 7. In addition, when used for a long period of time, the groove 9 and the steel ball 7 wear out, the feeding accuracy of the gear ridge 2 deteriorates, printing misalignment occurs, and it has the disadvantage that it cannot support three-primary color printing or graphic printing. .

FIG. 2 is an exploded perspective view showing another example of the conventional gear ridge drive device, in which a spiral groove 11 is formed at 1° of the gear ridge shaft. On the gear ridge 12, a slider 13 is inserted into a bearing 14 attached to the gear ridge 12 from the lower part of the gear ridge 12, and rotatably supported by a retaining ring 15 such as an E-ring. Here, the lower end 16 of the slider 13 is loosely fitted into the spiral groove 11,
Spiral groove 1 as the carriage shaft 1o rotates
The carriage 12 slides guided by the gear ridge guide shaft 1 and reciprocates along the gear ridge guide shaft 1 arranged parallel to the axis of the platen 17.

In addition, the groove width W of the spiral groove 11 and the width t of the tip portion 160 are:
Since the tip 16 slides in the groove 11, the required allowable gap must be set〇i.e. w-t=ca
) Gap must be set. In such a configuration, printing misalignment occurs due to the gap G, making it difficult to realize graphic printing and three primary color overlapping printing.

Also, after long-term use, the groove 11 and the lower end 1 of the slider
6 wears out and the gap progresses, resulting in a serious drawback in that the accuracy of carriage feeding further deteriorates.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention provides a gear IJ drive that is extremely simple, does not require high-precision parts, has an inexpensive structure, and improves carriage drive precision, and also eliminates printing deviation due to deterioration of drive precision. It is an object of the present invention to provide a printing device having a carriage drive mechanism which is extremely effective when performing graphic printing and three primary color overlapping printing which are particularly affected by the above effects. , a spiral groove is formed in a gear ridge shaft that guides a gear ridge carrying a print head along the platen, and the gear ridge is rotatably supported on the gear ridge, and one end of the gear ridge is loosely fitted in the groove;
The slider has a slider that slides while being guided by the groove, and the other end of the slider is given a rotational biasing force against the rotational force of the gear ridge shaft by a biasing spring on the carriage. Therefore, one end of the slider is configured to be in close contact with both side walls of the spiral groove of the gear ridge shaft, so as to constantly control the gap. That is, when the gear ridge shaft is rotated by a driving means such as a motor, the gear ridge on which the print head is mounted reciprocates along the platen.

However, the gear ridge drive accuracy is greatly improved, and the drive yrR degree does not deteriorate due to wear of the slider or the like.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.g FIG. 3 is an exploded perspective view showing an embodiment of the present invention. In the figure, let's first describe the configuration.

The print head 19 is mounted on the gear ridge 2o, and the platen 23 is arranged between the chassis 22 on both sides parallel to the gear ridge shaft 21 and the carriage shaft 21 (although shown separately from the chassis 22 on both sides in the figure).
It is rotatably positioned in the platen holding openings 24 of the chassis 22 on both sides via platen bearings 25 .

) and is wound around the platen 23.
Print on 6. A spiral groove 27 is formed in the gear ridge shaft 21, and a slider 28 is rotatably supported on the gear ridge 20 by a bearing 29 disposed on the gear ridge 2o, and one end 30 of the slider 28 is formed in the groove. 27
It is loosely fitted inside. Further, an H cut portion 3-1 is formed at the other end of the slider 28. In FIG. 4, the U-shaped spring 32 is guided by the boss 33 and the elongated hole 34 on the gear ridge 20, and the H-cut portion 31f is configured to be clamped.
O:';, - It is attached onto the gear ridge 20 with screws or the like via the holding member 35. The gear ridge guide shaft 36 is a shaft that is arranged parallel to the gear ridge shaft 21 and guides the gear ridge 20 along the platen 23. The motor 37 in Fig. 3 has a flat belt 38 and a pulley 3.
This is a driving means for rotating the gear ridge shaft 21 via the gear ridge shaft 9.

FIG. 5 is an enlarged perspective view of a main part of the present embodiment, and the groove width W of the spiral groove 27 and the width t of one end 30 of the slider 28 are defined as In order to do this, a required allowable gap G=W-t is set.

To explain the operation of this embodiment configured as above, in FIGS. 3 and 4, the gear ridge drive motor 37
When the gear ridge shaft 21 rotates, the gear ridge shaft 21 rotates via the flat belt 38 and the pulley 39. When rotated in the direction of arrow a, one end 3o of the slider 28 loosely fitted into the spiral groove 27 is guided into the groove 27 and slides, causing the gear ridge 2o to slide in the direction of the arrow. Here, as shown in FIG. 5, the H-cut portion 31 of the slider 28 is held by a U-shaped spring 32 as shown by the dotted line, and biasing forces are applied in the directions of arrows c and d, so that the H-cut portion 31 of the slider 28 moves in the direction of arrow e. try to rotate. In other words, the gap of 2 G between the slider 28O* parts 30 (d, W-) is rotated by the U-shaped spring 32 against the rotational force of the gear ridge shaft 21, so the gap becomes zero. As shown in FIG. 6, one end 3 of the slider 28
If the rotation angle of 0 = α, then in ΔA'OA, 9-fold ΔBO becomes LA'OA-α
In A, 1BOA: β.

In △B'0CVC, (B'OC= 9♂-(α+β
), W Therefore, from W-T2G, OB' and T are constants given by the shape of one end 30 of the slider 28. Therefore, 0=0
When the U-shaped spring 32 provides a rotation angle α such that the one end 30 constantly slides in close contact with both side walls of the groove 27.

With the above configuration, the gear ridge 20 reciprocates along the platen 23 due to the rotation of the gear ridge shaft 21, so it is possible to provide a gear one-knot drive device with extremely high precision. Further, there is no need to make the force ratio between the one end 30 of the slider 28 and the spiral groove 27 severe, and furthermore, there is no deterioration in accuracy due to wear of both.

In addition, in this embodiment, a U-shaped spring (wire material) was used for the rotational biasing force of the slider, but the same effect can be obtained by using a coiled spring, plate material, etc. Also, the shape of the slider can be varied. Deformation is possible.

Effects of the Invention As described above, the present invention uses an extremely simple mechanism to control the rotation gap of a slider sliding in a spiral groove, thereby improving drive accuracy and preventing deterioration of drive accuracy due to wear. In addition, there is no need to require more precision in parts machining than necessary, so @! , it is possible to obtain an inexpensive gear ridge drive device. This is particularly effective in high-density printing, graphic printing, and three-primary color overlapping printing, in which printing misalignment has a large impact on printing quality9.

3 is an exploded perspective view of a printing device according to an embodiment of the present invention, FIG. 4 is an exploded perspective view of the same essential parts, FIG. 5 is an enlarged perspective view of the same, and FIG. 6 is a plan view of the main parts. It is a diagram.

19... Print head -20... Carriage, 21... Carriage shaft, 22-...
-... Chassis, 23... Platen, 24-
...Platen holding hole, 25...Bearing for platen, 26...Paper, 27...---
Spiral groove, 28...Slider, 29...
...Bearing, 31...H cut part, 32...
... U-shaped spring, 34 ... Long hole, 35 ...
...Holding member, 36... Carriage guide shaft, 37... Motor, 38...
Flat belt, 39...Pulley.

Claims (1)

[Claims] The shaft includes a shaft formed with a spiral groove, a slider that is loosely fitted into the spiral groove and slides while being guided by the groove, and a biasing spring that biases the slider. What is claimed is: 1. A printing device characterized in that the printing device is rotatably supported by a bearing carrying the shaft, and a rotational biasing force is applied to the slider by the biasing spring against the rotational force of the shaft.