JPH0739652Y2 - Dot printer - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a dot printing device, and more particularly to a dot printing device that can always operate a printing nozzle normally to perform accurate printing.

[Prior art]

Japanese Patent Laid-Open No. 61-14315 discloses a dot printing device that prints characters and symbols by ejecting paint (ink) from a printing nozzle.
There is a dot matrix printing device disclosed in 1 etc. In a conventional dot matrix printer, normally, as shown in the schematic perspective view of FIG. 2, a plurality of print nozzles 12 connected to a print head 10 are vertically arranged side by side. A solenoid valve built in the print head is opened / closed by a control signal, and paint is jetted from the print nozzle 12 to print desired characters / symbols on the target surface. When the printing device is used intermittently for a long time, the scattered paint adheres to and accumulates around the nozzle. Further, if the unused state continues for a long period of time, the nozzle tip may be clogged with paint. As described above, if the paint adheres to the periphery of the nozzle or the nozzle is clogged, the print head becomes abnormal. In particular, for example, in the case of intermittent use, when the printing is started after the non-use state, the printing dot at the start time or the like is (A) misaligned as schematically shown in FIG. , (B) fading, (C) scattering, (D) clogging, etc., and normal printing cannot be performed. In the figure,
The broken line shows the clean dot position. Therefore, conventionally, as shown in FIG. 2, a cleaning liquid is sprayed from the cleaning nozzle 16 arranged above to the tip of the print nozzle 12 to clean the nozzle tip, and the periphery of the nozzle tip is cleaned. Is going. This discarding is performed to fill the nozzle with the paint and to form a thin film of the paint at the tip of the nozzle. This thin film prevents the solvent from evaporating from the paint with which the nozzle is filled, and when the next printing is started, the thin film is quickly broken and the paint is ejected to perform normal printing. Therefore, in order to always print with accurate dots from the start of printing, clean the nozzle tip at the end of printing in the previous stage,
It is extremely important to form a paint thin film having an appropriate strength on the tip of the nozzle in the clean state.

[Problems to be solved by the device]

However, as shown in FIG. 2, when cleaning the nozzles 12 from the outside with the cleaning nozzles 16 arranged above the plurality of printing nozzles 12 arranged in parallel in the vertical direction, the melted paint May adhere to another nozzle located below, and the nozzle may be clogged due to the adhered paint. Therefore, as described above, even if the paint is thrown away after cleaning the nozzle, a thin film having an appropriate thickness cannot be formed at the tip of the nozzle. As a result, the dot printing apparatus shown in FIG. However, there is a problem that it may not be possible to print with normal dots from the start of printing. An object of the present invention is to provide a dot printing device that can accurately print with normal print dots even when printing is restarted after the dot printing device is stopped.

[Means for achieving the object]

The present invention is a dot printing apparatus that prints on a target surface by spraying paint from a print nozzle connected to a print head, cleans the tip of the print nozzle in preparation for the next printing, and coats a suitable paint thin film on the tip. In order to dispose of the paint for forming the ink, a cleaning liquid injection unit for injecting a cleaning liquid into the nozzle is provided in the print nozzle, and a cleaning nozzle included in the cleaning liquid injection unit is provided in the middle of the print nozzle. By directly connecting, the said subject was achieved.

[Action]

In the present invention, since the print nozzle provided in the dot printing apparatus is provided with the cleaning liquid injecting means for injecting the cleaning liquid into the nozzle, even when a plurality of print nozzles are vertically arranged, Since each print nozzle can be washed separately, it is possible to prevent the paint dissolved in the cleaning liquid from adhering to the print nozzle below the print nozzle located above. Since the cleaning can be performed from the inside with a predetermined injection pressure, all the printing nozzles can be kept clean after the cleaning. Therefore, when the paint is discarded and blown to the print nozzle after the cleaning, it is possible to always form a paint thin film having properties such as appropriate strength at the nozzle tip.
Since the printing in the next stage can be started with normal dots from the beginning, it is possible to always print accurate characters and symbols.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an enlarged schematic perspective view showing a printing section which is a main part of a dot printing apparatus according to an embodiment of the present invention. The dot printing apparatus of the present embodiment has substantially the same basic configuration as the printing apparatus shown in FIG. 2, and the printing unit has a plurality of printing units shown in FIG. 1 arranged side by side in the vertical direction. Have a configuration. The printing unit includes a print nozzle 22 connected to the print head 20.
And a cleaning means 30 connected to the print nozzle 22. A paint pump 24 for supplying paint to the print nozzle 22 at a predetermined injection pressure is connected to the print head 20, and
A controller 26 is connected which outputs a control signal for timing the spraying when the supplied paint is instantaneously sprayed from the tip of the nozzle 22 and characters or symbols are printed on the surface of the target. The cleaning means 30 includes a cleaning head 32 and a cleaning nozzle 34 directly connected to the cleaning head 32, and a tip of the cleaning nozzle 34 is connected to the print nozzle 22 in a T-shape. . A cleaning pump 36 for injecting the cleaning liquid into the print nozzle 22 through the cleaning nozzle 34 at a predetermined pressure (high pressure) is connected to the cleaning head 32, and the cleaning liquid is injected at a timing. The controller 38 for outputting the control signal of is connected. Next, the operation of this embodiment will be described when the print target is an electric resistance welded tube. As described above, the dot printing apparatus of the present embodiment has the above-mentioned printing units arranged in parallel in the vertical direction with the cleaning means 30 in the horizontal direction, for example, eight printing units, and the printing nozzles of the printing units arranged in parallel. 22 are arranged at regular intervals with their tips oriented in the same horizontal direction. Then, the electric resistance welded pipe is moved to a position near the tip of the nozzle 22 at a predetermined speed, and the paint is sprayed from the nozzle 22 onto the surface of the electric resistance welded pipe. At that time, each print head 20
Based on the control signal from the controller 26 connected to the head, the electromagnetic valve (not shown) built in the head 20 is opened / closed to correspond to the print head at a predetermined position of the electric resistance welded pipe. Spray the paint. By spraying the paint from the print nozzle 22 appropriately for each of the printing units arranged in parallel, desired characters, symbols, etc. are printed on the surface of the electric resistance welded pipe. After the above-described printing is completed for a predetermined number of, for example, one lot of electric resistance welded pipes, a solenoid valve (not shown) built in the cleaning head 32 is opened / closed based on a control signal from the controller 38 to wash the cleaning pump 36. The cleaning liquid from is injected into the print nozzle 22 through the cleaning nozzle 34, and is ejected from the tip of the nozzle 22 to clean the nozzle 22. After the cleaning is completed, the solenoid valve of the print head 20 is operated again, the paint is ejected from the print nozzle 22 to perform a waste blowing, and the entire inside of the nozzle 22 is filled with the paint, for example, the electric sewing of the next lot. Wait until the tube is sent. According to the present embodiment, after performing the predetermined printing process, the cleaning means 30 can clean each print nozzle from the inside thereof, so that the print nozzle positioned below as in the conventional example, It is possible to reliably prevent the paint from being attached when the upper print nozzle is washed. At the same time, since the inside of the nozzle is cleaned, the inside of the print nozzle 22 can be easily and surely cleaned, so that the nozzle clogging can be reliably prevented. Further, as described above, since the paint is discarded and blown to the clean print nozzle 22, the thin film (acting as a lid) formed by evaporation of the solvent at the tip of the nozzle also has the paint inside the nozzle. Are attached as foreign matter, and moreover, it is possible to make the state of being homogeneous and having appropriate properties as compared with the case where the nozzle is clogged. Therefore, when printing is restarted, the lid made of the thin film can be easily removed, and the nozzle clogging can be completely prevented. Therefore, dot printing can be accurately performed from the start to the normal position where the original printing should be performed. As a result, according to the dot printing apparatus of the present embodiment, since normal dot printing can be performed from the beginning of printing restart, accurate printing can always be performed. Even if the film formed on the tip of the nozzle becomes thicker 1 to 2 hours after the waste blowing, the inside of the nozzle is cleaned, so that the inside of the nozzle can be surely kept clean. Actually, when the pipe number was printed on the electric resistance welded pipe by the dot printing device of the present embodiment, in the case of the conventional dot printing device, troubles due to nozzle clogging occurred 10 times within 6 months. On the other hand, in the case of this example, no trouble occurred even once, and it was possible to always print accurately. The present invention has been specifically described above, but it goes without saying that the present invention is not limited to the one shown in the above embodiment. For example, the specific configuration of the cleaning means is not limited to the one shown in the above embodiment. Further, the number of print nozzles, the arrangement direction of the print nozzles and the like can be arbitrarily changed, and the print target is not limited to the electric resistance welded tube.

[Effect of device]

As described above in detail, according to the present invention, even when the printing is restarted after the dot printing device is stopped, it is possible to print with normal printing dots from the start, so that accurate dot printing is always performed. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a dot printing apparatus of the present invention, FIG. 2 is a schematic perspective view showing a main part of a conventional dot printing apparatus, and FIG. 3 is an explanation showing problems of the conventional method. It is a figure. 22 …… Print nozzle, 30 …… Cleaning means, 34 …… Cleaning nozzle, 36 …… Cleaning pump.

Claims (1)

[Scope of utility model registration request] 1. A dot printing apparatus that prints on a target surface by spraying paint from a print nozzle connected to a print head, cleans the tip of the print nozzle in preparation for the next printing, and appropriately paints the tip. A cleaning liquid injection unit for injecting a cleaning liquid into the nozzle is provided in the print nozzle in order to dispose of the paint for forming a thin film, and the cleaning nozzle included in the cleaning liquid injection unit is provided in the print nozzle. A dot printing device characterized by being directly connected to.