JPS58157199A - Cooling fan trouble detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling fan failure detection device for detecting failure of a cooling fan that cools driving means for driving printing hammers arranged side by side.

When the hammer coils that drive the printing hammers installed for each digit generate heat when continuously energized, the temperature of the hammer fill itself and the inside of the frame increases significantly.

This reduces the function of the hammer coil, resulting in deterioration of print quality such as poor character alignment and a decrease in print density. Furthermore, if printing is continued for a long time with the cooling fan stopped, various parts within the frame will thermally expand, causing serious problems such as malfunctions and damage to component parts.

FIG. 1 is a diagram showing a schematic configuration of a printing mechanism section to which a cooling device is added. Printing hammers 4, which face the type band 1 via the ink ribbon 2 and paper 3 and are arranged along the printing position, are driven by an electromagnetic actuator 5 including the hammer fill. A duct 8 is provided behind the actuator 5 and extends in the same direction as the printing hammer 4 for blowing cooling air from a cooling fan 6 supplied through a hose 7 onto the actuator 5 . 9
is a connector that connects the cooling fan 6 and the hose 7.

As shown in FIG. 2, a sensor 11 for detecting a failure of the cooling fan 6, such as a stoppage, is attached to the connector 9 via a holder 10. The sensor 11 is composed of a heating element 12 and a temperature sensing element 13, as is well known.

With such a configuration, that is, the sensor 11 is provided within the connector 9, the air path area is reduced by the surface area of the sensor 11 and the holder 10, and the air path resistance increases, resulting in loss of air volume and reduced cooling effect. There's a problem.

In order to obtain the desired cooling effect, the cooling fan 6 must have a large capacity, but this is not a good idea in terms of mounting space and power consumption. In addition, since the sensor 11 is located inside the connector 9, air volume loss may occur due to air leakage due to incomplete fixation of the hose 7 and duct 8, and air volume loss due to paper scraps, dust, etc. adhering to the spout of the duct 8. There are drawbacks such as the inability to detect

Note that the duct 8 needs to blow cooling air at a uniform speed over all the digits of the actuator 5. However, due to restrictions on the mounting position of the cooling fan 6, cooling air is supplied from the negative side in the longitudinal direction of the duct 8, so the wind speed on the opposite supply side becomes smaller than the wind speed on the supply side, making effective cooling impossible. There is a problem. For this reason,
Measures have been taken, such as adding a special partition plate to the duct 8 or making the shape of the ejection port of the duct 8 complicated, but these are undesirable because they complicate the structure and increase manufacturing costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling fan failure detection device that eliminates the above-mentioned drawbacks of the prior art and allows a desired cooling effect to be obtained without increasing the capacity of the cooling fan.

The present invention focuses on the fact that the sensor does not increase the air path resistance between the duct and the duct, and can be installed in a place where there is a predetermined wind speed. It is characterized by being attached to the wall.

That is, a window for mounting a sensor is provided on the wall on the opposite side of the supply side of the duct, and the sensor is mounted through a holder having an opening in the window. The present invention will be explained below with reference to FIGS. 3 and 4 showing examples.

Cooling air from a cooling fan 6 having a constant wind speed and volume is guided by a hose 7 and supplied to a duct 8. In duct 8,
A long outlet 81 is provided for blowing out cooling air in a direction perpendicular to the extending direction, and a window 82 is provided in the wall on the opposite side to the supply side. The sensor 11 is attached to the window 82 via the holder 20. The holder 20 is provided with an opening 21 . Therefore, a portion of the cooling air supplied to the duct 8 flows through the opening 21, that is, the space between the holder 20 and the sensor 11, so that the sensor 11 can detect a failure of the cooling fan 6. Moreover, by selecting an excessive area of the opening 21, the wind flowing from the opening 21! This makes it possible to make the speed of the cooling air blown out from the jet nozzle 81 substantially uniform over all digits.

As described above, according to the present invention, since the sensor is attached to the final stage of the air path, the air path resistance does not increase, the cooling effect can be improved, and a small-capacity cooling fan can be used. becomes. It is also possible to detect abnormalities such as loss of air volume due to abnormalities in assembly or adhesion of paper waste.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of a conventional device applied to a printing device, FIG. 2 is a sectional view taken along line I-■ in FIG. 1, and FIG. 3 is a perspective view showing an embodiment of the device of the present invention. FIG. 4 is a side view seen from the right side of FIG. 3. In the figure, 4 is a printing hammer, 5 is an electromagnetic actuator, 6 is a cooling fan, 7 is a hose, 8 is a duct, 9 is a connector, 10, 20 is a holder, 11 is a sensor, 12 is a heating element, 13 is a temperature sensing element , 21 is an opening, 81 is a spout, 82
is a window.

Claims (1)

[Claims] 1. A duct that extends in the same direction as a plurality of objects to be cooled arranged side by side and has an air outlet in a direction perpendicular to the direction in which the duct extends, and a hose that is connected to the duct from one side in the direction in which it extends. A cooling fan failure detection device comprising: a cooling fan that supplies cooling air through a cooling fan; and a sensor comprising a heating element and a temperature sensing element mounted on a window on the other side wall in the direction in which the duct extends. . 2. The cooling fan failure detection device according to claim 1, wherein the sensor is attached to a window on the other side wall of the duct via a holder having an opening. 3. The cooling fan failure detection device according to item 2 of the scope of Patent No. 11113'3, characterized in that a space for forming a cooling air path is provided between the opening of the holder and the sensor. 4. The cooling fan failure detection device according to claim 1, wherein the object to be cooled is a driving means for driving printing hammers arranged in parallel along the printing position.