JPH0591855U - Line dot printer print head cooling device - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a cooling device for a hammer bank of a line dot printer that has no temperature difference depending on the location. [Structure] Smaller dynamic pressure reducing plates 13-2 and 13- are provided at the blower-side end and the anti-blower-side end in the wind guide tube 12, respectively.
3 is provided, and a large dynamic pressure reducing plate 13-1 is provided in the central portion of the air guide tube 12 in the longitudinal direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a print head cooling device for a line dot printer.

[0002]

[Prior Art]

As shown in FIG. 1, a conventional print head cooling device for a line dot printer is provided with a heat sink 9 on a degaussing coil 5, and the cooling air of a cooling blower 11 is passed between a fin 10 of a heat sink 9 via a wind guide tube 12. It was made to flow to. In the figure, 1 is a print pin attached to the tip of a leaf spring 2 of a spring-charge type hammer arranged in plural along a print line, 3 is a yoke part, 4 is a permanent magnet, 5 is a degaussing coil, 6 Is an ink ribbon, 7 is a printing paper, and 8 is a platen. Because of the structure of the conventional cooling device shown in FIG. 1, the wind speed V is high on the blower side of the air guide tube 12, so that the dynamic pressure Pd of the ventilation flow is large, and the static pressure Ps is small. Therefore, the inflow of air between the fins 10 of each heat sink is small (the wind speed on the surface of the fins 10 of the heat sink is slow and it is hard to cool), and conversely, the wind speed is low on the side of the blower tube 12 opposite the blower. The dynamic pressure Pd is small and the static pressure Ps is large. Therefore, the amount of air flow into the fins 10 of each heat sink increases. (The wind velocity Vh flowing on the surface of the fin 10 of the heat sink becomes faster, so that it is easy to cool.) This will be described below with reference to FIG. Now, when air is flowing in the wind guide tube, the following equation (1) is established according to the law of conservation of energy. P _T = P _s (x) + γ / 2g · V ² (x) + ΣP _f (x) = constant (1) where P _T : total pressure, P _s (x): static pressure kg / m ² γ: Specific gravity of air kg / m ³ V (x): Wind speed m / sec γ / 2g · V ² (x) = Pd (x); Dynamic pressure kg / m ² ΣP _f (x): Pipeline wall surface Cumulative pressure loss due to eddy current (kg / m ² Therefore, the static pressure P _s (x) that contributes to the inflow of air between the fins 10 of the heat sink is represented by the following equation: P _s (x) = PT− (Pd (X) + ΣP _f (x) (1 ′) In the case of the conventional structure of the air guide tube shown in FIG. 1, since the ventilation resistance in the conduit is small and the end of the conduit is closed, the blower side higher dynamic pressure Pd is larger close to (and hence the static pressure P _s is small), the dynamic pressure Pd is rapidly decreased as it approaches the end of Matakanro (hence static pressure P The difference in Ps between the inlet and the end of the pipeline is large, so the wind speed of the fin tubes of each heat sink near the inlet of the pipeline is low, and the wind speed at the end of the pipeline is high, so the hammerbank For the above reasons, a large temperature difference occurs between the blower side and the non-blower side of the hammer bank in the conventional cooling device along the longitudinal direction of the hammer bank. There was a problem such as the overheating and the heat deformation of the hammer bank.

[0003]

[Problems to be solved by the device]

 Therefore, the present invention provides a cooling device that has a structure in which any fin is hit with a uniform wind speed to eliminate the temperature difference depending on the location, prevent abnormal deformation of the hammer bank, and prevent the occurrence of irregular print dots. Is what you are trying to do.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a large size dynamic pressure reducing plate that is curved to face the flow of wind in the central portion of the wind guide tube in the longitudinal direction, and A dynamic pressure reducing plate smaller than the dynamic pressure reducing plate is provided in the vicinity of both ends of the blower side and the anti-blower side.

[0005]

[Action]

As described above, if a dynamic pressure reduction plate is provided in the wind guide tube, the increase in pressure loss ΣP _f due to wind overflow and friction with the pipe wall surface increases as the blower tube moves from the blower side to the anti-blower side. As a result, the dynamic pressure Pd gradually decreases toward the anti-blower side. Therefore, the static pressure P _s can be made substantially constant along the longitudinal direction of the air guide tube, and the amount of air flowing between the heat sink fins is almost the same, which eliminates the above-mentioned problem.

[0006]

【Example】

FIG. 3 shows an embodiment of the present invention, which is different from the conventional structure shown in FIG. 1 in that the large-sized curved surface of the seat sink 9 is curved in the air guide tube 12 facing the ventilation flow. Equipped with a dynamic pressure reducing plate 13-1 of size (a size that closes the cross section of the duct of the wind guide pipe by about 1/2), and a size smaller than this dynamic pressure reducing plate 13-1 (the duct pipe line This is the point that dynamic pressure reducing plates 13-2 and 13-3 having a similar shape and having a cross section of about 1/5 are provided near the blower side and near the blower side, respectively. The dynamic pressure reducing plate may have a flat shape without being curved as illustrated. According to the structure of the present invention, as shown in FIG. 4, a part of the dynamic pressure Pd is changed to the static pressure P _S by the dynamic pressure reducing plate 13-2 provided near the inlet of the pipeline, and the dynamic pressure reducing plate 13- The dynamic pressure Pd of the air flow flowing over 2 is also reduced by the dynamic pressure reducing plate 13-1 provided at the center of the pipeline and the dynamic pressure reducing plate 13-3 provided before the end of the pipeline. since contributing to the raising of the pipe during the static pressure P _S, which is the static pressure P _S Gaho Isuzu constant in the longitudinal direction of the conduit. Therefore, the wind velocity of the air flowing between the fins of each heat sink becomes almost constant, and the temperature difference between the hammers becomes small.

[0007]

[Effect of the device]

 According to the present invention, since the temperature difference in the longitudinal direction of the hammerbank is small, 1) there is no heat spot, local overheating of the degaussing coil is eliminated, and the life of the coil can be extended and a drying accident can be prevented. 2) It is possible to prevent irregular printing due to thermal deformation of the hammer bank. 3) Excessive ventilation is not required and a small blower is sufficient.

[Brief description of drawings]

FIG. 1 is a vertical side view and a transverse plan view of a conventional cooling device.

FIG. 2 is an explanatory diagram showing the operation of the air guide tube of the cooling device shown in FIG.

FIG. 3 is a vertical side view and a cross-sectional plan view of an embodiment of the present invention.

FIG. 4 is an explanatory view showing the operation of the air guide tube in the embodiment of the present invention.

[Explanation of symbols]

 1 Printing Pin 2 Leaf Spring 3 Yoke 4 Permanent Magnet 5 Degaussing Coil 6 Ink Ribbon 7 Printing Paper 8 Platen 9 Heat Sink 10 Fin 11 Cooling Blower 12 Windpipe

Claims (1)

[Scope of utility model registration request] 1. A hammerbank provided with a heatsink having a plurality of fins in a direction perpendicular to a print line on a hammerbank, one end of which is closed along the lengthwise direction of the heatsink, and the other end of which is provided with a fan or a blower. In a print head cooling device for a line dot printer in which an air guide tube for ventilation cooling is arranged, a small dynamic pressure reducing plate is provided near the fan or blower mounting portion in the air guide tube and at the end of the anti-fan or anti-blower side. A print head cooling device for a line dot printer, characterized in that a large dynamic pressure reducing plate is provided in the center of the air guide tube in the longitudinal direction.