JPH078194Y2 - Impact dot printer print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a print head of an impact dot printer.

(Prior Art) An impact dot printer that selectively drives a plurality of wires by an electromagnet to write a character or the like according to recording information on a recording medium has a large base portion in which a plurality of drive electromagnets are annularly arranged and these It has a long nose for gathering multiple print wires, which are selectively driven by electromagnets, into the width of the font.

By the way, in order to configure this type of printer to print at a higher speed, it is necessary to shorten the print wire as a movable part as much as possible to reduce the inertia and improve the responsiveness. For this purpose, it is necessary to make the driving electromagnet smaller and to arrange the print wires in the central part in parallel to the central part as much as possible, and at the same time to make the magnetic attraction force of the electromagnet stronger. With this configuration, a large impact force is applied to the lever that supports the base end of the printing wire each time printing is performed, not only the durability of the printer is significantly impaired, but also the As seen in Japanese Patent No. 94529, in a conventional printer in which heat is dissipated from the electromagnetic coil by heat radiation fins provided on the outer periphery, the printer is densely arranged when a large number of characters or solid images are continuously printed. There arises a problem that heat from the electromagnet cannot be sufficiently removed.

(Problems to be Solved) The present invention has been made in view of such a problem, and an object thereof is to absorb the impact force to the print lever as much as possible and at the same time to prevent the electromagnetic force from densely arranged electromagnets. Another object of the present invention is to provide a new impact dot printer which is capable of effectively discharging heat and printing at a higher speed and which is also highly durable.

(Means for Solving the Problem) That is, the present invention is, as an impact dot printer for achieving such a problem, a low-rigidity and non-magnetic metal that encloses a plurality of annular electromagnets from the back side of a print head. In the center of the inner surface of the cover body made of a material, a resin plate is provided at the top that abuts the tip of the printing wire support lever, and a projection having a thickness that contacts the side of each electromagnet is integrally formed and The fins for heat dissipation are integrally formed on the outer surface so that the heat of the electromagnets that are densely arranged can be efficiently discharged immediately to the outside of the cover body by the heat conduction effect, and the impact force that acts on the print lever can be reduced. It is designed to absorb as much as possible and to damp vibrations rapidly.

(Example) Then, the Example illustrated below is described.

In the figure, reference numerals 1 ... Represent a large number of cores projectingly provided on one surface of the annular magnetic plate 2. On each end surface of these cores 1 ... At times, the magnetic flux from the permanent magnet plate 3 attached to one surface of the magnetic plate 2 attracts and holds the plungers 6 against the elasticity of the leaf spring integrated with the printing lever 5, and at the time of printing,
By selectively energizing the electromagnetic coil 4 provided so as to cancel the magnetic flux, the attraction of the plunger 6 is released, and the print wire 7 provided at the tip of the print lever 5 is pushed from the tip of the nose 11 by the elastic force of the leaf spring. It is configured to project by printing.

Reference numeral 10 denotes a nose 11 formed to cover the print lever base end supporting annular plates 8 and 8, the permanent magnet plate 3 and the annular magnetic plate 2 from the print lever 5 side of the print mechanism thus configured. A cooling fin 12 is provided on the outer peripheral surface of the front cover 10 as an integral front cover, and the heat of the electromagnetic coil 4 transferred to the cover 10 via the plates 2, 3, and 8 is applied to the cooling fin 12. Is configured to be released to the outside.

By the way, reference numeral 15 in the drawing denotes a rear cover which covers the printing mechanism from the side of the annular magnetic plate 2, and the rear cover 15 is made of a non-magnetic material, preferably a non-magnetic metal material such as aluminum or an aluminum compound having a relatively small rigidity. A large-diameter heat sink projection 16 is formed at the center of the inner surface of the annular magnetic plate 2 to penetrate the inner space surrounded by the electromagnetic coils 4 to draw in heat from this portion. Further, a plate 17 made of a hard resin material is provided on the end surface of the convex portion 16 so as to come into contact with the tip 5a of the print lever 5 during non-printing.
Is additionally provided, and a slight gap is formed between the plunger 6 and the core 1 when the print lever 5 is in contact. On the other hand, on the outer surface of the rear cover 15, that is, on the rear end side of the dot head, at the center of the pulse motor,
A cooling fan 19 driven by 18 is provided, and
Around the fan 19, a large number of cooling fins 20 are radially provided around the fan 19, and the electromagnetic coil 4 transmitted to the convex portion 16 through the silicon filler 21 having good thermal conductivity.
The heat of ... Is immediately guided to the outside of the rear cover 15 by the heat conduction effect, and is efficiently radiated by the cooling fan 19 and the cooling fins 20.

In the figure, reference numeral 9 is a heat conducting material interposed between the electromagnetic coils 4 ... And the annular metal plates 2, 3 and 8 provided on the outer periphery thereof. As the heat conducting material, an insulating alumite treatment is applied to the surface. A putty or the like is used in which a large amount of applied aluminum or metal powder is mixed to improve thermal conductivity. Further, reference numeral S is a temperature detection sensor embedded in the convex portion 16, which accurately detects the temperature at the position closest to the electromagnetic coil 4 and switches to a printing mode in which the energization amount is suppressed when the temperature rises, When the temperature further rises, a signal for stopping the printing operation is output.

In the above-described embodiment, a large amount of heat generated during high-speed printing is stored in the inner space of each electromagnetic coil 4 arranged at a high density in the central portion of the dot head, but most of this heat is Electromagnetic coil 4 ... Immediately rear cover due to heat conduction
It flows through 15 to the cooling fin 20, where it is forcibly radiated by the cooling fan 19.

When the amount of heat generated by the electromagnetic coil 4 exceeds the amount of heat released due to a high-density printing operation or an abnormal printing operation such as a black solid image, the rear cover is brought close to the electromagnetic coil 4. The temperature detection sensor S attached to the inner surface of 15 quickly and accurately catches the temperature rise of the electromagnetic coil 4, and the output signal switches to the print mode in which the energization amount is suppressed or the print operation is stopped.

On the other hand, at the time of printing, the plunger 6 is reversed by the intermittent energization of the electromagnetic coil 4 and is attracted to the end surface of the core 1, and accordingly, the leaf spring integrated with the print lever 5 is elastically deformed. The tip of the protrusion strongly abuts on the end face of the convex portion 16. As described above, the convex portion 16 is formed to have a thickness sufficient to fill the inner space surrounded by the electromagnetic coils 4 ... Since a hard resin plate 17 for shock absorption is attached to the portion, the lever 5 that abuts with a wide contact surface here has its impact force greatly reduced by the elastic action of the resin plate 17, and Due to the relatively low rigidity of this portion, the vibration at the time of collision is largely damped, and the standby operation for the next printing is rapidly started.

Although the above-described embodiment has been described by taking the example of the spring charge type wire dot head, the present invention can be applied to other direct suction type wire dot heads, and the head can be made particularly compact. If you need to configure the cooling fins from the outer surface of the front cover 10.
12 can also be removed.

(Effect) As described above, according to the present invention, since the protrusion for the heat sink which is in close contact with the side portion of the electromagnet is provided in the center of the inner surface of the cover body, a large number of them are arranged in direct contact with the electromagnet which is the heat source. The heat generated from the electromagnet can be directly and efficiently discharged to the outside by the heat conduction effect.

In addition, since the resin material that contacts the print lever is added to the top of the protrusion formed with a large diameter of low-rigidity material, the impact force applied to the print lever is dispersed by the wide contact surface and the elasticity of the resin material causes the impact force. Absorbs the damage and suppresses the damage and reduces the impact noise as much as possible, and at the same time, the protrusion made of a low-rigidity material damps the vibration of the printing lever rapidly and prevents rebundling, ensuring accurate and quick printing operation. Furthermore, by collecting the ends of the wire at the top of the protrusion, that is, in the center, the bending of the wire is reduced, and the wear of the wire guide and the frictional resistance of the wire are greatly reduced. You can

[Brief description of drawings]

FIG. 1 shows a print head of an impact dot printer which is an embodiment of the present invention. FIG.
FIG. 2 is a plan view showing one half in cross section. 1 ... Core, 4 ... Electromagnetic coil 5 ... Printing lever, 6 ... Plunger 7 ... Printing wire, 10 ... Front cover 15 ... Rear cover, 16 ... Projection 17 ... Resin plate, 19 ... … Cooling fan 20… Radiating fin, S… Temperature detection sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B41J 29/00 R

Claims (1)

[Scope of utility model registration request] 1. An impact dot printer of the type wherein impact printing is performed by selectively driving a printing wire by a plurality of electromagnets arranged in an annular shape, which has a low rigidity and covers the plurality of electromagnets from the back side of a print head. At the center of the inner surface of the cover body made of a non-magnetic metal material, a resin plate that abuts against the tip of the print wire supporting lever is provided at the top, and a protrusion that is in close contact with the side portion of each electromagnet is integrally formed, and the cover is formed. A print head for an impact dot printer, characterized in that fins for heat dissipation are integrally formed on the outer surface of the body.