JPS6030379A - Serial printer - Google Patents

Abstract

PURPOSE:To effectively cool the printing head of a serial printer, by constituting a spacing shaft for the horizontal moving guide of the printing head as a heat pipe to dissipate head of said printing head. CONSTITUTION:A spacing shaft 19 for horizontally moving a printing head 5 is equipped with fins 17 cooled by electromotive forced air passing and has an operating medium 33 received therein to constitute a head pipe. In this case, the heat generated to the head 15 is dissipated through a carriage 16 and the shaft 19 to effectively cool the printing head of a serial printer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a serial printer, and particularly to a structure for efficiently cooling its print head.

[Prior art and its problems]

With the spread of information processing equipment, particularly word processors and personal computers, the demand for particularly compact and inexpensive printers has increased rapidly in recent years. Printers for this type of use have made remarkable progress in terms of performance, especially when looking at the printing speed of wire dot printers, alphanumerics can achieve 120 characters/second, and Kanji characters can reach ω characters/second. There is.

However, this printing speed is much slower than the information processing speed of a computer, and as a result, the information processing speed of the entire system or the output speed of the processing results is limited by the operating speed of the printer. Improving the operating speed of this printer has become a major technical challenge.

There are various types of serial printing, such as the electric printing type, the thermal printing type, the shape-retaining printing type, and the wire dot printing type.
Plain paper can be used and multiple sheets can be printed simultaneously.
Furthermore, because of their advantages such as relatively simple mechanisms and high reliability, wire dot type printers account for approximately 9ONs of all serial printers. Therefore, a major technical challenge has emerged to take advantage of the advantages of this wire dot type printer while further speeding it up.Wire dot type serial printers generally have a 0 platen configuration as shown in Figure 1. A print head 5, which is fed in a horizontal direction, is positioned opposite to the printing paper 2 that is intermittently fed by the rotation of the printing paper 2, through an ink ribbon 4 that is gradually wound up by a ribbon reel 3, and the printing paper 2 is moved in a horizontal direction to the required printing paper position, that is, horizontally. A cooling fin 7 is attached to the print head 5, which prints characters, symbols, figures, etc. formed by a dot matrix at a predetermined position by driving and driving the necessary print wires 6 of the print head 5 at the directional position. This is designed to be cooled by an electric fan 8. The print head 5 is attached to a carriage 16. The carriage 16 is guided by a pair of spacing shafts 9 and 10 arranged parallel to the platen 1, and is guided by a spacing motor 1 arranged at one end of the paper width.
The toothed belt 14 hung between the goo 171.2 attached to the goo 171.2 and the goo υB placed on the other end side and the joint part I
5 and driven horizontally.

In this type of wire dot serial printer,
For example, if you want to print kanji using a matrix of different x U dots at a general printing speed of 40 characters/sec, each printing wire and its drive mechanism will have a maximum speed of 40 x 100 characters/sec.
The wire dot serial This has emerged as a problem that needs to be solved when speeding up printers.

There are various driving methods for the printing wire 6, one of which is a spring release type. This spring-open type means that the printing wire 6 is attached to the armature, which is suspended by a leaf spring, and the position where the printing wire 6 is pulled away from the printing paper 2 by the attractive force of a permanent magnet is normally attracted to the coil. This is a system in which the attractive force of the permanent magnet is canceled by passing a driving current, and the armature, that is, the printing wire 6 is driven by the spring force of the leaf spring to perform printing. In this method, the driving energy required for one driving operation of one printing wire is 2
0(V)X2(g)X 300X 10-'(6)=
12
If it operates at a duty ratio of 0X, that is, a frequency of 500 times/second, one print wire will consume 6W of power, and the entire print head 5 with u print wires will consume 1W of power.
It can be seen that the power consumption is extremely large at 44W.

Even though a large amount of heat is generated due to the large amount of power consumed, since the print head 5 is a serial printer, it must always move horizontally and must rely on heat dissipation or cooling by air cooling or wind cooling. However, it is difficult to do this effectively. Therefore, conventionally, the temperature rise of the print head 5 has been monitored by a temperature sensor such as a thermistor, and if the temperature exceeds an allowable temperature, the print speed has to be automatically lowered or the operation has to be stopped. Therefore, even if the desired printing speed can be achieved in a short time,
There was a drawback that the average printing speed in the case of continuous printing over a long period of time was significantly reduced.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and aims to provide a serial printer equipped with means for effectively cooling the print head.

[Summary of the Invention] In order to achieve the above object, the present invention configures the spacing shaft, which is usually made of a metal rod-shaped member, as a heat pipe, and transfers the heat generated in the print head, which is a movable part, to the carriage and the print head. This system is characterized by being efficiently guided to the outside via a pacing axis.

[Embodiments of the invention]

FIGS. 2 and 3 show an embodiment of the present invention. The feature of this printer is that the spacing shaft 19 is configured as a heat pipe, and a heat dissipation fin 17 is attached to the end of the spacing shaft 19, which is connected to an electric fan 18.
This is due to the fact that it is configured to be cooled by wind. Carriage 1
No. 6 cooling fins and an electric fan to cool them are not provided. The other components are the same as those in FIG.

The print wire 6 of the print head 5 is fixed to an armature 22 suspended by a leaf spring 21. The armature n is always in contact with the core U due to the attractive force of the permanent magnet path against the spring force of the leaf spring 21 (when not driven). During printing, current is applied to the coil 5 wound around the circumference υ of the core 24 to cancel the magnetic force of the permanent magnet B, and the spring force of the leaf spring 21 causes the armature 22 and the printing wire integrated with it to be 6 is driven toward the printing paper 2 and printed. The printing wire 6 is guided to the correct dot position by a wire guide arranged on the front end surface of the cover 27 of the printing head 5 assembled on the base path.

The print head 5 is attached to the carriage 16 by means of a bolt 29 with good thermal conductivity.
A bearing 30 is press-fitted onto the inner circumferential side of the carriage 16, and the carriage 16 is connected to a shaft configured as a heat pipe through the bearing 30 made of a sintered oil-impregnated bearing material such as copper, which has high thermal conductivity. Pacing axis】9 and slides.

The spacing shaft 19 has a wick 32 made of metal fiber or the like arranged on the inner surface of a metal tube 31 having good thermal conductivity.
A working medium 33 such as water is sealed inside to form a heat pipe.

The print head 5 has several to 24 or more built-in coils 5 depending on the number of printing wires mentioned above, and the electric power consumed during printing, that is, the amount of heat generated, is considerably large.

This heat generation is caused by Joule heat when current flows through the coil, and by hysteresis loss and eddy current loss in the magnetic circuit composed of the core, armature 22, etc. In the embodiment shown in Figures 1 and 3, the main heat generating parts such as the coil 5 and the core U are directly attached to the base 4, and the base path itself is attached to the carriage 16 with good thermal conductivity. ing. Furthermore, the carriage 16 is in contact with the spacing shaft 19 via a bearing I having good thermal conductivity.

Therefore, the heat generated by the print head 5 is transferred to the spacing shaft 1 through the spacer 4, the carriage 16, and the bearing.
9 is transmitted well. The spacing axis 19, that is, the heat pipe, is 800 to 10
Therefore, regardless of the position of the carriage 19, a large amount of heat is transmitted to the heat dissipation fins 17 provided at the ends with a low temperature difference, and this is transferred to the outside. can be released to The radiation fins 17 are fixed in position, so that they can always receive the appropriate amount of air cooling from the electric fan 18 regardless of the position of the print head 5. Arrow A in FIG. 3 indicates a heat transfer path.

FIG. 4 shows another embodiment of the invention.

In this embodiment, the ends of the spacing shafts 19 configured as heat pipes are not provided with heat dissipation fins, but instead are provided with metal frames 34 having a large surface area, to which the various components of the printer are attached. The print head 5 is cooled by natural heat dissipation from the frame 34. According to this embodiment, cooling means such as radiation fins and electric fans are not required.
This is advantageous in terms of simplification of configuration and cost reduction. Arrow B is
It shows the heat transfer path in this example.

Although the above embodiments have been explained using wire dot type print heads as an example, the present invention is not limited to wire dot type print heads, and can be applied to any type of serial printer print head as long as it generates heat. It can also be applied with similar effects.

〔Effect of the invention〕

As described above, according to the present invention, cooling of the print head, which is a problem when increasing printing speed, can be efficiently cooled externally by configuring the spacing shaft, which is a guide for horizontal drive of the print head, as a heat pipe. This makes it possible to remove the heat generated by the print head with extremely low thermal resistance, which eliminates the problem of high-speed printing in terms of heat generation.

[Brief explanation of drawings]

Fig. 1 is a layout diagram of a conventional serial printer, Fig. 2 is a layout diagram showing an embodiment of the present invention, and Fig. 3 is a sectional view of the main part showing the detailed structure of the main part of the embodiment of Fig. 2. , FIG. 4 is a layout diagram showing another embodiment of the present invention.0 1...Platen, 2...Print paper, 3...Ribbon reel, 4...Ink ribbon, 5... print head,
Printing wire for 6, 16... Carriage, 17... Heat radiation fin, 19... Spacing shaft, 2]... Leaf spring, 22... Armature, Field... Permanent magnet, U...
...Core, 5...Coil, Swimming...Base, 30...
Bearing, 31...Metal tube, 32...Wick, 33.
... Working medium, 34... Frame.

Claims (1)

[Claims] l) A spacing shaft that guides the horizontal movement of the print head is constructed as a heat pipe, and heat generated by the print head is transmitted to the spacing shaft via a sliding member with good thermal conductivity. This serial printer is characterized in that heat is radiated to the outside from this spacing axis. 2) The serial printer according to claim 1, characterized in that a heat dissipation fin is provided at the end of the spacing shaft03) The serial printer according to claim 1, characterized in that a heat radiation fin is provided at the end of the spacing shaft. A serial printer characterized in that the end of the pacing shaft is attached to the frame of the printer to which the print head is attached with good thermal conductivity.