JPH0470995B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling device for a printer using a plurality of electromagnets, particularly a line printer.

[Prior Art] A conventional apparatus will be explained based on a line printer shown in FIG.

Reference numeral 1 denotes a printing hammer, and a hammer bank 2 is formed in which printing hammers 1 are combined for 136 digits per line in the direction of printing digits. An ink ribbon 4, a type belt 5, and a platen 6 are arranged in a machine frame 7 parallel to the hammer bank 2 with a printing paper 3 in between.

The hammer bank 2 is equipped with an electromagnet 8 for each hammer 1 to drive the hammer 1, and it is the largest source of heat in the line printer because current flows for each print. A blower duct 10 with a cooling blower fan 9 fixed thereon is placed over the hammer bank 2, and the electromagnet 8
We are trying to prevent burnout accidents.

[Problems to be Solved by the Invention] In line printers, out of a total of 136 hammer drive electromagnets, the regular electromagnets that are always used for printing are generally around the 1st to 80th characters. It is extremely rare to drive electromagnets from about 80 characters to 136 characters, and they are used as emergency magnets.

However, in the above conventional example, since the cooling air sent out by the blower fan 9 is blown onto all the electromagnets through the duct 10, even the emergency electromagnets that are rarely used in the hammer bank are cooled, and the cooling air is not effective. It was not used and had an inefficient configuration, requiring a large blower fan.

This invention solves the above-mentioned problems by blowing cooling air to the regular electromagnet until the emergency electromagnet reaches a dangerous temperature before a burnout accident occurs. The purpose of this is to change the air flow path and blow cooling air to the emergency electromagnets when they become cold.

[Means for Solving the Problems] The present invention includes a plurality of printing hammers provided along the printing digit direction, and a plurality of printing hammers provided to one end in the digit direction corresponding to the printing hammers so as to drive the printing hammers. In a printing device that has a plurality of regular electromagnets arranged in the opposite direction and a plurality of non-use electromagnets arranged in the opposite direction, the blower fan generates cooling air, and the two electromagnets are arranged at one end of the opening and the blower fan is arranged at the other end. A duct is placed in the duct to form an air passage for blowing cooling air to both electromagnets, and a duct is placed in the duct to close the cooling air passage leading to the emergency electromagnet to remove the heat generated from the emergency electromagnet. The air duct can be changed between the first position, which prevents the cooling air from escaping, and the second position, which opens the cooling air duct leading to the emergency electromagnet and blows cooling air to the emergency electromagnet. When the temperature of the ventilation switching means and the emergency electromagnet is at a dangerous temperature, the ventilation switching means is arranged close to the emergency electromagnet in a cooling air passage leading to the emergency electromagnet so as to be movable from a first position to a second position. A cooling device for a printing machine, comprising: a shape-memory alloy spring; and a return spring that moves a blower switching means from a second position to a first position when the shape-memory alloy spring is inactive. This is what we provide.

[Example] Hereinafter, an example of the present invention will be described based on FIG. 1 of the drawings.

2 is a hammer bank, in which 136 printing hammers are provided along the printing digit direction opposite to the platen 6 and via the ink ribbon 4, and the same number of electromagnets (not shown) drive the printing hammers.
is fixed.

A blower duct 10 (air blowing means) to which a blower fan 9 for sending cooling air is fixed at one end covers the electromagnet of the hammer bank 2.

In this duct 10, a butterfly valve (air blowing switching means) 11 is installed so as to be rotatable about an orthogonal axis perpendicular to the direction of the printing digit, in the vicinity of an electromagnet for driving a printing hammer for printing the 80th character. This butterfly valve 11 has a
The cooling air sent by the blower fan 9 can be selectively formed into the following two airflow paths. Firstly, as shown in Figure 1, spraying is only possible on the electromagnets that are normally used for printing, from the electromagnet in the 1st digit to the electromagnet in the 80th digit (first position).
Second, as shown in Figure 2, it is possible to spray on all electromagnets (second position), including electromagnets that are not always used for printing, such as emergency electromagnets from the 80th digit to the last digit. It is.

Reference numeral 12 denotes a shape memory alloy spring installed between the duct 10 and the butterfly valve 11 and arranged so that the elastic modulus of the spring changes depending on the temperature of the emergency electromagnet. When the emergency electromagnet reaches a dangerously high temperature, this shape memory alloy spring 12 contracts as shown in Figure 2, pulls and rotates the butterfly valve, and opens the passage of the blower fan 9, allowing the cooling air to flow completely. Configure it so that it can be sprayed onto an electromagnet.

13 is a return spring fixed to the opposite side of the rotation axis from the shape memory alloy spring 12 in the butterfly valve 11;
Together with 2, it constitutes a driving means for the butterfly valve 11. The elastic force of the spring 12 is set to be weaker than the elastic force when the shape memory alloy spring 12 is contracted, and stronger than the elastic force when the shape memory alloy spring 12 is in the natural state of being stretched.

Next, the action will be explained.

In Figure 1, if only the regular electromagnet is used without any particular use of the emergency electromagnet, the emergency electromagnet is at room temperature, and the return spring 1
The butterfly valve 11 is rotated by the elasticity of No. 3, and the air passage is changed so that the cooling air is blown only to the regular electromagnets.

For this reason, the cooling air is blown concentrated on the electromagnets that are regularly used during printing, so the cooling effect is high and there is no waste.

In FIG. 2, when the emergency electromagnet is used, the elasticity of the shape memory alloy spring 12 becomes stronger than the elasticity of the return spring 13 when the temperature rises to a dangerous temperature before a burnout accident occurs. , the butterfly valve 11 is reversed and rotated to switch and form the air passage so that cooling air can be blown onto all the electromagnets including this emergency electromagnet.

For this reason, since the emergency electromagnet is used infrequently, it is already cooled down, and burnout accidents can be prevented. Furthermore, since the regular electromagnet is continuously blown with cooling air, the temperature will not rise to a dangerous level immediately.

In this way, when the temperature of the emergency electromagnet decreases, the elasticity of the return spring becomes stronger than the elasticity of the shape memory alloy spring, so the return spring rotates the butterfly valve 11 to blow the cooling air. A ventilation path is formed so that the air is blown onto the regular electromagnet.

[Other Embodiments] FIG. 3 shows another embodiment in which an electromagnetic solenoid 1 is used to drive the butterfly valve 11.
4 is used. Also, a temperature sensor 15 for detecting the temperature of the electromagnet for emergency use, and this temperature sensor 1
This electromagnetic solenoid 1 is
The control unit 16 that controls the drive unit 4 constitutes a driving means.

Depending on whether the emergency electromagnet is at room temperature or at a dangerous temperature, the control unit 16 drives the butterfly valve by turning the electromagnetic solenoid 14 ON or OFF based on the detection by the temperature sensor 15, and cools the air passage only to the ordinary electromagnet. It is possible to select between sending air or sending cooling air to all electromagnets.

[Effects of the Invention] The structure and operation of the present invention are as described above, and the cooling air is limited to the regular electromagnet depending on when the temperature of the emergency electromagnet is at room temperature or at a dangerous temperature before a burnout accident occurs. to form a ventilation path that allows air to be blown.
Or, since we have created an air passage that can blow air to all electromagnets, cooling air can be selectively blown to the electromagnets that have a high temperature and need to be cooled, increasing cooling efficiency and making it smaller than conventional blower fans. A blower fan can be used.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention,
FIG. 2 is a diagram showing a state where the emergency electromagnet is at normal temperature, FIG. 2 is a diagram showing a state at a dangerous temperature, FIG. 3 is a diagram showing another embodiment, and FIG. 4 is a diagram showing a conventional line printer. 11...Butterfly valve, 12...Shape memory alloy spring, 13...Return spring.

Claims (1)

[Claims] 1. A plurality of printing hammers provided along the printing digit direction, and a plurality of regular electromagnets arranged toward one end in the digit direction in correspondence with the printing hammers so as to drive the printing hammers. and a plurality of emergency electromagnets arranged in opposite directions, a blower fan that generates cooling air, and both electromagnets arranged in an opening at one end and the blower fan at the other end, a duct forming an air passage for blowing cooling air to the emergency electromagnet; and a duct disposed within the duct to close the cooling air passage leading to the emergency electromagnet so as to prevent heat generated from the emergency electromagnet from escaping through the cooling air. and a second position where the cooling air passage leading to the emergency electromagnet is opened and the cooling air is blown to the emergency electromagnet. a shape memory alloy spring disposed close to the emergency electromagnet in a cooling air passage leading to the emergency electromagnet so as to be able to move the ventilation switching means from the first position to the second position when the temperature of the electromagnet is at a dangerous temperature; A cooling device for a printing machine, comprising: a return spring that moves the ventilation switching means from the second position to the first position when the shape memory alloy spring is inactive.