JP4319049B2 - Volatile substance adhesion prevention mechanism and volatile substance adhesion prevention method on the lower surface of an inkjet head of an inkjet printer - Google Patents

Description

  The present invention prevents evaporation of ink droplets that have landed on the surface of a medium of an ink jet printer from the ink droplets on the surface of the ink jet printer, and prevents volatile substances that float and stay in the outside air around the ink jet head from condensing and adhering. , A volatile substance adhesion preventing mechanism (hereinafter simply referred to as a volatile substance adhesion preventing mechanism) on the lower surface of the inkjet head of the inkjet printer, and a volatile substance adhesion preventing method (hereinafter referred to as the volatile substance adhesion preventing method) on the lower surface of the inkjet head of the inkjet printer using the mechanism. Simply referred to as a method for preventing the attachment of volatile substances).

As shown in FIG. 6, nozzles (not shown) arranged on the lower surface of the inkjet head 30 that move relatively above the platen 20 in the XY directions (the horizontal direction and the front and back directions in the drawing) substantially parallel to the surface of the platen 20. Inkjet printers are known in which ink droplets are ejected in a dot-like manner on the surface of a medium (recording medium) 10 such as a sheet mounted on the platen 20. According to this printer, a picture or / and a character consisting of an array of a plurality of ink dots can be printed on the surface of the medium 10 mounted on the platen 20.
In the printer of FIG. 6, the pinch roller 42 and the feed roller 44 are arranged to face each other above and below the upper surface of the platen 20 on which the medium 10 is mounted. The medium 10 sandwiched between the pinch roller 42 and the feed roller 44 is transported on the platen 20 in the X direction (lateral direction in the figure) corresponding to the rotation direction of the feed roller 44. On the other hand, the inkjet head 30 has a structure that travels in the Y direction (front and back direction in the figure) above the medium 10 mounted on the platen 20. The inkjet head 30 has a structure that moves relative to the XY direction above the medium 10.

Recently, this type of printer uses a solvent ink with excellent weather resistance and water resistance, in which ink pigment or ink dye is dissolved in a highly volatile organic solvent in the ink supplied to the inkjet head 30. There is something to do.
According to the printer using solvent ink, a plurality of ink droplets are ejected from nozzles arranged on the lower surface of the ink jet head 30 and landed in a dot shape on the surface of the medium 10 mounted on the platen 20. It is possible to print a pictorial figure and / or characters which are composed of an array of dots of solvent ink and which have excellent weather resistance and water resistance. Then, the media on which the pictures or / and the characters are printed can be widely used for outdoor advertisements that require weather resistance and water resistance.

In this printer using solvent ink, as shown in FIG. 6, heating such as an electric heater that heats the media mounted on the platen 20 through the platen 20 inside the platen 20 below the traveling path of the inkjet head 30. Means 50 are incorporated.
According to the printer in which the heating means 50 is built, the solvent ink droplets that are ejected from the nozzles arranged on the lower surface of the inkjet head 30 and land on the surface of the medium 10 mounted on the platen 20 below the heating means 50. Thus, the medium 10 is forcibly heated together with the medium 10 via the platen 20 to quickly evaporate the highly permeable organic solvent contained in the ink droplets in the outside air. The ink droplets that have landed on the surface of the medium 10 can be quickly dried to prevent the ink droplets from penetrating into the medium 10 around the landed portion. Then, it is possible to prevent the formation of blurred large-diameter ink dots on the surface of the medium 10 and to accurately form small-diameter ink dots on the surface of the medium 10. Then, it is possible to print a sharp and clear picture or / and character consisting of an array of a plurality of small-diameter solvent ink dots on the surface of the medium 10 without blurring spots and blurring.
Pub. No. : US2002 / 0109767 A1

However, in the ink jet printer in which the heating unit 50 is built in the platen 20 as described above, the solvent ink droplets landed on the surface of the medium 10 heated by the heating unit 50 evaporate into the outside air, A volatile substance such as an organic solvent that floats and stays in the vicinity of the inkjet head 30 is exposed to the outside air to cause condensation on the lower surface of the inkjet head 30 in a low temperature state. Adhered as small particles. The volatile substances attached to the lower surface of the inkjet head 30 hindered smooth and accurate ejection of ink droplets from the nozzles arranged on the lower surface of the same inkjet head 30.
As a result, the flying miracle of the ink droplets ejected from the nozzles on the lower surface of the inkjet head 30 bends in a biased direction deviating from the normal direction, or the ink droplets from the nozzles on the lower surface of the inkjet head 30 do not become granular. In addition, the ink droplets ejected in the form of a fine mist are sprayed and dispersed widely on the surface of the medium 10 mounted on the platen 20 below the mist, The surface of the media 10 was soiled extensively. Furthermore, ink droplets are not accurately ejected from the nozzles on the lower surface of the inkjet head 30, and ink dots are printed at locations where ink dots should be present on a part of a picture or / and character printed on the surface of the medium 10. A so-called dot dropout that does not exist is generated, and a striped pattern or the like is generated in the picture or / and the character.

The present invention has been made in view of such problems, and is heated by heating means from the ink droplets ejected from the nozzles arranged on the lower surface of the ink jet head and landed on the surface of the medium mounted on the platen as described above. Volatile substances such as organic solvents that evaporate in the outside air form condensation on the lower surface of the inkjet head, and the volatile substances interfere with the smooth and accurate ejection of ink droplets from the nozzles aligned on the lower surface of the inkjet head. It is a first object to provide a volatile substance adhesion prevention mechanism that can prevent the above.
In addition, volatile substances such as organic solvents that are heated by heating means from the ink droplets landed on the surface of the media mounted on the platen and evaporate into the outside air adhere to the bottom surface of the inkjet head, and the volatile It is a second object of the present invention to provide a volatile substance adhesion prevention method capable of preventing substances from interfering with the smooth and accurate ejection of ink droplets from nozzles arranged on the lower surface of an inkjet head.

  In order to achieve the first object, the first volatile substance adhesion preventing mechanism of the present invention detects a platen temperature T and a first detection means for detecting an outside air temperature t around the inkjet head of the inkjet printer. The difference ΔT (ΔT = T−t) between the second detection means, the platen temperature T detected by the second detection means, and the outside air temperature t detected by the first detection means has reached a predetermined value or more. At this time, the lower surface of the inkjet head on which the nozzles are lined is wiped repeatedly with a wiper every predetermined time, and evaporated from the ink droplets that have landed on the media surface. And a wiping means for removing water.

  In order to achieve the second object, the first volatile substance adhesion prevention method of the present invention is a volatile substance adhesion prevention method using the first volatile substance adhesion prevention mechanism of the present invention. When the difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection means and the outside air temperature t around the inkjet head detected by the first detection means reaches a predetermined value or more. In addition, the wiping means is used to repeatedly wipe the lower surface of the inkjet head where the nozzles are lined up with a wiper every predetermined time, evaporate from the ink droplets that have landed on the media surface, and form condensation on the lower surface of the inkjet head. It is characterized by removing volatile substances.

According to an experiment described later, a volatile substance that is heated by a heating unit from ink droplets that are ejected from nozzles arranged on the lower surface of the inkjet head and landed on the surface of the medium, evaporates into the outside air. When the difference ΔT from the ambient temperature t around the inkjet head that is exposed to a low temperature is higher than a predetermined temperature, for example, 20 ° C., condensation occurs and adheres to the lower surface of the inkjet head where the nozzles above it are aligned To be confirmed.
On the other hand, the volatile substance that evaporates into the outside air from the ink droplets that have landed on the surface of the medium is when the difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head is smaller than a predetermined temperature such as 20 ° C., for example. It was confirmed that there was almost no condensation on the lower surface of the inkjet head where the nozzles above it were lined up.

Therefore, in the first volatile substance adhesion prevention method using the first volatile substance adhesion prevention mechanism, the platen temperature T detected by the second detection means and the first detection means are detected. The difference ΔT from the outside air temperature t around the inkjet head reaches a predetermined value or more, and volatile substances evaporated in the outside air from the ink droplets landed on the media surface are condensed on the lower surface of the inkjet head. When the wiping means is activated, the lower surface of the ink jet head on which the nozzles are arranged can be wiped with a wiper repeatedly and accurately every predetermined time without delay. Then, the wiper can accurately and accurately remove volatile substances that evaporate from the ink droplets that have landed on the surface of the medium into the outside air and adhere to or adhere to the lower surface of the inkjet head without delay.
On the other hand, if the difference ΔT between the platen temperature T detected by the second detection means and the outside air temperature t around the inkjet head detected by the first detection means does not reach a predetermined value, the wiping means is used. The wiping of the lower surface of the inkjet head on which the nozzles are lined up with a wiper every predetermined time can be stopped. Then, the lower surface of the inkjet head in a state where the volatile substance evaporated in the outside air from the ink droplets landed on the surface of the medium is not likely to be condensed or attached to the lower surface of the inkjet head. It is possible to prevent the wiper from wiping unnecessarily and repeatedly with a wiper. And, the life of the ink-jet head is shortened by the abrasion of the lower surface of the ink-jet head in which the nozzles are lined, or the life of the wiping means is shortened by abrasion of the wiper of the wiping means. Can be prevented.

  In order to achieve the first object, the second volatile substance adhesion preventing mechanism of the present invention includes a temperature raising means for raising the temperature of the inkjet head and a first temperature for detecting the outside air temperature t around the inkjet head. Detection means, second detection means for detecting the platen temperature T, difference ΔT (ΔT = T) between the platen temperature T detected by the second detection means and the outside air temperature t detected by the first detection means -T) is equal to or greater than a predetermined value at which the volatile substance evaporated from the ink droplets landed on the surface of the medium is condensed on the lower surface of the inkjet head, and the volatile substance evaporated from the ink droplet is condensed on the lower surface of the inkjet head. Ink jet head temperature adjusting means for preventing the ink jet head from adhering by adjusting the temperature of the ink jet head by the temperature raising means is provided. is doing.

  In order to achieve the second object, the second volatile substance adhesion prevention method of the present invention is a volatile substance adhesion prevention method using the second volatile substance adhesion prevention mechanism of the present invention. The difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection unit and the outside air temperature t around the inkjet head detected by the first detection unit is equal to or greater than a predetermined value. Prevents volatile substances evaporated from ink droplets that have landed on the surface of the media from condensing and adhering to the lower surface of the ink jet head by adjusting the temperature of the ink jet head using the ink jet head temperature adjusting means. It is characterized by.

  In the second volatile substance adhesion prevention method using this second volatile substance adhesion prevention mechanism, the platen temperature T detected by the second detection means and the periphery of the ink jet head detected by the first detection means Ink jet head so that the difference ΔT (ΔT = T−t) with respect to the outside air temperature t does not exceed a predetermined value where volatile substances evaporated from ink droplets that have landed on the surface of the medium are condensed and attached to the bottom surface of the ink jet head. Using the temperature adjusting means, the temperature of the inkjet head can be adjusted by the temperature increasing means. The difference ΔT (ΔT = T−t) between the platen temperature T and the outside air temperature t around the inkjet head becomes a predetermined value or more, and the volatile substance evaporated from the ink droplets landed on the medium surface It is possible to prevent condensation from adhering to the lower surface.

  In order to achieve the first object, the third volatile substance adhesion preventing mechanism of the present invention includes a first detection means for detecting the outside air temperature t around the inkjet head, and a first detection means for detecting the platen temperature T. The difference ΔT (ΔT = T−t) between the two detection means, the platen temperature T detected by the second detection means, and the outside air temperature t detected by the first detection means becomes a predetermined value or more, There is a platen temperature adjusting means for adjusting the heating temperature of the platen by the heating means to prevent the volatile substances evaporated from the ink droplets landed on the media surface from condensing and adhering to the lower surface of the inkjet head. It is characterized by that.

  In order to achieve the second object, the third volatile substance adhesion prevention method of the present invention is a volatile substance adhesion prevention method using the third volatile substance adhesion prevention mechanism of the present invention. The difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection unit and the outside air temperature t around the inkjet head detected by the first detection unit is equal to or greater than a predetermined value. By using the platen temperature adjustment means, the heating temperature of the platen by the heating means is adjusted to prevent the volatile substances evaporated from the ink droplets that have landed on the surface of the media from condensing and adhering to the lower surface of the inkjet head. It is said.

  In the third volatile substance adhesion prevention method using the third volatile substance adhesion prevention mechanism, the platen temperature T detected by the second detection means and the periphery of the ink jet head detected by the first detection means Platen temperature so that the difference ΔT (ΔT = T−t) with respect to the outside air temperature t does not exceed a predetermined value at which the volatile substances evaporated from the ink droplets landed on the surface of the medium are condensed and attached to the lower surface of the inkjet head. By using the adjusting means, the heating temperature of the platen by the heating means can be lowered. Then, the difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head becomes a predetermined value or more, and volatile substances evaporated from ink droplets that have landed on the surface of the medium are condensed and attached to the lower surface of the inkjet head. Can be prevented.

As described above, according to the first volatile substance adhesion prevention method of the present invention using the first volatile substance adhesion prevention mechanism of the present invention, the platen temperature T and the outside air temperature t around the inkjet head are When the difference ΔT reaches a predetermined value or more, the wiping means can be operated so that the lower surface of the inkjet head on which the nozzles are lined can be wiped accurately and without delay repeatedly by a wiper every predetermined time. Then, the wiper can accurately remove the volatile substance that evaporates from the ink droplets that have landed on the surface of the medium and condenses or starts to adhere to the lower surface of the inkjet head from the lower surface of the inkjet head without delay.
On the other hand, if the difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head does not reach a predetermined value, the wiping means is used to repeatedly wipe the lower surface of the inkjet head on which the nozzles are arranged with a wiper every predetermined time. Can be stopped. Then, the lower surface of the inkjet head in a state where the volatile substance evaporated in the outside air from the ink droplets landed on the surface of the medium is not likely to be condensed or attached to the lower surface of the inkjet head. It is possible to prevent the wiper from wiping unnecessarily and repeatedly with a wiper. The life of the inkjet head is shortened by, for example, rubbing the lower surface of the inkjet head in which the nozzles are lined up, or the life of the wiper is shortened by rubbing the wiper of the wiping means. Can prevent.
Further, according to the second volatile substance adhesion preventing method of the present invention using the second volatile substance adhesion preventing mechanism of the present invention, the difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head is The volatile substances evaporated from the ink droplets that have landed on the surface of the medium to the outside air are condensed on the lower surface of the inkjet head and adhere to the bottom surface of the inkjet head. It can be prevented by adjusting the temperature rise by the temperature means.
Further, according to the third volatile substance adhesion preventing method of the present invention using the third volatile substance adhesion preventing mechanism of the present invention, the difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head is The volatile substances evaporated from the ink droplets landed on the surface of the medium to the outside air dew and adhere to the lower surface of the ink-jet head using the platen temperature adjusting means. The heating temperature can be adjusted to prevent it.

  1 and 2 show a preferred embodiment of an ink jet printer provided with a first volatile substance adhesion preventing mechanism of the present invention, FIG. 1 is a schematic structural explanatory view thereof, and FIG. 2 is a front view of the periphery of the wiper. FIG. Below, the 1st volatile substance adhesion prevention mechanism with which this inkjet printer was equipped is demonstrated.

The first volatile substance adhesion preventing mechanism provided in the ink jet printer shown in FIGS. 1 and 2 includes a first detecting means 100 for detecting an outside air temperature t around the ink jet head 30 of the ink jet printer, and a platen temperature T. And second detection means 102 for detecting.
The first detection means 100 is a thermistor 32 embedded in the inkjet head 30, and based on the thermistor 32 for directly measuring the temperature of the inkjet head 30 and the temperature of the inkjet head 30 measured by the thermistor, The estimation unit 104 estimates the outside air temperature t around the inkjet head 30.
According to experiments, it was confirmed that the inkjet head temperature T and the outside air temperature t around the inkjet head 30 have a certain correlation. When this experimental example is described in detail, JV3-130SP manufactured by Mimaki Engineering Co., Ltd. was used as the experimental printer. Then, it was confirmed that the inkjet head temperature T and the outside air temperature t around the inkjet head have a certain correlation as shown in FIG. When this correlation is expressed by a mathematical formula, T = 0.92t + 7.8.
Therefore, the estimation means 104 is composed of an electronic circuit or the like that can obtain a calculation result represented by such a mathematical expression. The estimating means 104 is configured so that the outside air temperature t around the inkjet head 30 can be estimated almost accurately from the inkjet head temperature T measured by the thermistor 32.
In addition, it can be easily estimated that mathematical expressions representing the correlation between the inkjet head temperature T and the ambient air temperature t around the inkjet head 30 are different each time the type of inkjet printer is different. Therefore, it goes without saying that the electronic circuit or the like of the estimating means 104 needs to be different every time the type of the ink jet printer is different.
The second detection means 102 is a thermistor 22 embedded in the platen 20, and includes a thermistor 22 that directly measures the platen temperature T.

Further, the first volatile substance adhesion prevention mechanism provided in the ink jet printer shown in FIGS. 1 and 2 includes the platen temperature T detected by the second detection means 102 and the first detection means 100. When the difference ΔT (ΔT = T−t) with respect to the outside air temperature t reaches a predetermined value such as 20 ° C. or more, the lower surface of the inkjet head 30 on which nozzles (not shown) are arranged is wiped by the wiper 108 every predetermined time. The wiping means 106 removes volatile substances that evaporate from the ink droplets that have landed on the surface of the medium 10 and are condensed by touching the lower surface of the inkjet head 30 to adhere to or start to adhere to the lower surface of the inkjet head 30. Is provided.
As shown in FIGS. 1 and 2, the wiping means 106 has a difference ΔT between the platen temperature T detected by the second detection means 102 and the outside air temperature t detected by the first detection means 100, for example, 20 The comparison circuit 107 composed of an electronic circuit or the like for detecting that the temperature has reached a predetermined value such as ° C., and that the difference ΔT between the platen temperature T and the outside air temperature t has reached a predetermined value or more by the comparison circuit. When detected, as shown in FIG. 2, the inkjet head 30 is repeatedly moved to the maintenance area 40 arranged on the side of the platen 20 every predetermined number of minutes, for example, every few minutes, and is raised in the maintenance area 40. A combination of an electronic circuit, an electric motor, and the like for performing an operation of repeatedly wiping the lower surface of the inkjet head 30 with a wiper 108 made of a rubber plate or the like. The ink jet head travel control means 109 is a combination of the two.

  Other parts of the ink jet printer provided with the first volatile substance adhesion preventing mechanism shown in FIGS. 1 and 2 are configured in the same manner as the ink jet printer shown in FIG.

  Next, a preferred embodiment of the first volatile substance adhesion preventing method of the present invention using the first volatile substance adhesion preventing mechanism provided in the ink jet printer shown in FIGS. 1 and 2 will be described. explain.

  In this first volatile substance adhesion prevention method, the first detection means 100 detects the outside air temperature t around the inkjet head 30. Specifically, the temperature of the inkjet head 30 measured by the thermistor 32 embedded in the inkjet head 30 is used to estimate the outside air temperature t around the inkjet head 30 by the estimation means 104. At the same time, the platen temperature T is detected by the second detection means 102. Specifically, the platen temperature T is directly measured by the thermistor 22 embedded in the platen 20. A difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection unit 102 and the outside air temperature t around the inkjet head 30 detected by the first detection unit 100 is, for example, 20 When the temperature reaches a predetermined value such as ° C. or higher, the wiping means 106 is operated to repeatedly wipe the lower surface of the inkjet head 30 on which the nozzles are arranged with a wiper 108 every predetermined time. Specifically, the inkjet head traveling control means 109 repeatedly moves the inkjet head 30 to the maintenance area 40 on the side of the platen 20 every predetermined time, for example, every few minutes, and the wiper 108 provided in the maintenance area 40 is provided. Thus, the lower surface of the inkjet head 30 is repeatedly wiped. Then, volatile substances that evaporate from the ink droplets that have landed on the surface of the medium 10 and are deposited on or attached to the lower surface of the inkjet head 30 are removed from the lower surface of the inkjet head 30.

  The first volatile substance adhesion preventing method using the first volatile substance adhesion preventing mechanism shown in FIGS. 1 and 2 includes the above steps.

According to the experiment, the volatile substance that is heated by the heating means 50 from the ink droplets that are ejected from the nozzles arranged on the lower surface of the inkjet head 30 and landed on the surface of the medium 10 mounted on the platen 20 to evaporate in the outside air. When the difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head 30 that is exposed to the outside air and is in a low temperature state becomes equal to or higher than a predetermined temperature such as 20 ° C., It was confirmed that dew condensation adheres to the lower surface of the aligned inkjet heads 30.
On the other hand, the volatile substance that evaporates into the outside air from the ink droplets that have landed on the surface of the medium 10 has a difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head 30 that is smaller than a predetermined temperature such as 20 ° C., for example. In this case, it was confirmed that there was almost no condensation on the lower surface of the inkjet head 30 where the nozzles above it were arranged.

Tables 1 and 2 below show experimental examples of specific adhesion states of volatile substances on the lower surface of the inkjet head 30.
In this experimental example, JV3-130SP manufactured by Mimaki Engineering Co., Ltd. was used for the ink jet printer. For the ink, SPC-0347-2 manufactured by Mimaki Engineering Co., Ltd. was used. Polyester synthetic paper was used for the media. Table 1 shows an experimental example of whether or not volatile substances adhere to the lower surface of the ink jet head 30 when the 150 mm width (about 50 scans) band is continuously printed on the surface of the medium 10. Table 2 shows an experimental example of whether or not volatile substances adhere to the lower surface of the inkjet head 30 when a 300 mm width (about 100 scans) band is continuously printed on the surface of the medium 10. Whether or not volatile substances are condensed and adhered to the lower surface of the inkjet head 30 was confirmed using a CCD camera. In Tables 1 and 2, “X” indicates that the volatile substance is condensed on the lower surface of the inkjet head 30, “Δ” indicates that the volatile substance starts to be condensed on the lower surface of the inkjet head 30, Indicates that volatile substances do not adhere to the lower surface of the inkjet head 30 due to condensation.

From Tables 1 and 2, the volatile substance that is heated by the heating means 50 from the ink droplets that have landed on the surface of the medium 10 and evaporates into the outside air is the platen temperature T and the outside air temperature t around the inkjet head 30. It can be seen that when the difference ΔT is about 20 ° C. or more, condensation occurs and adheres to the lower surface of the inkjet head 30.
On the other hand, when the difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head 30 is smaller than about 20 ° C., the volatile substance that evaporates into the outside air from the ink droplets that have landed on the surface of the medium 10 It can be seen that there is almost no condensation on the lower surface of the inkjet head 30.

From this experimental result, in the first volatile substance adhesion prevention method using the first volatile substance adhesion prevention mechanism, the platen temperature T detected by the second detection means 102 and the first detection means The difference ΔT from the outside air temperature t around the inkjet head 30 detected by 100 reaches a predetermined value, for example, 20 ° C. or more, and the volatile substance evaporated in the outside air from the ink droplets landed on the surface of the medium 10 When the dew adheres to or begins to adhere to the lower surface of the upper inkjet head 30, the wiping means 106 is operated without delay, and the lower surface of the inkjet head 30 in which the nozzles are arranged is wiped by the wiper 108 every predetermined time. It can be seen that it can be wiped repeatedly and accurately. Then, the wiper 108 evaporates from the ink droplets that have landed on the surface of the medium 10 into the outside air, and removes volatile substances that adhere to or start to adhere to the lower surface of the inkjet head 30 without delay. It turns out that it will be possible.
On the other hand, when the difference ΔT between the platen temperature T detected by the second detection means 102 and the outside air temperature t around the inkjet head 30 detected by the first detection means 100 does not reach a predetermined value, for example, 20 ° C. It can be seen that the wiping means 106 can be used to stop repeatedly wiping the lower surface of the inkjet head 30 in which the nozzles are arranged with the wiper 108 every predetermined time. The volatile substance evaporated in the outside air from the ink droplets landed on the surface of the medium 10 is in a state where there is no possibility that the volatile substance is condensed or attached to the lower surface of the inkjet head 30 thereabove or starts to attach. It can be seen that it is possible to prevent the lower surface from being wiped unnecessarily and wastefully by the wiper 108 every predetermined time. The life of the inkjet head 30 is shortened by the abrasion of the lower surface of the inkjet head 30 in which the nozzles are lined, or the wiper 108 of the wiping means is scraped away. It can be seen that it is possible to prevent this.
Note that volatile substances that are heated from the ink droplets that have landed on the surface of the medium 10 mounted on the platen 20 and are evaporated into the outside air are condensed on the lower surface of the inkjet head 30 on which the nozzles above are lined up. The predetermined value of the difference ΔT between the platen temperature T and the outside air temperature t around the ink jet head 30 that adheres or starts to adhere varies with the type of ink jet printer. That can be easily guessed. For this reason, it goes without saying that the electronic circuit or the like constituting the comparison circuit 107 of the wiping means 106 needs to be sequentially changed in accordance with the type of the ink jet printer.

  FIG. 4 shows a preferred embodiment of an ink jet printer provided with the second volatile substance adhesion preventing mechanism of the present invention, and FIG. 4 is a schematic structural explanatory view thereof. The second volatile substance adhesion prevention mechanism will be described below.

The second volatile substance adhesion prevention mechanism provided in the ink jet printer is provided with a temperature raising means 110 for raising the temperature of the ink jet head 30. The temperature raising means 110 is composed of an electric heater, a hot air circulation pipe, a hot water circulation pipe and the like wound around the inkjet head 30.
Further, instead of the wiping means 106, the difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection means 102 and the outside air temperature t around the inkjet head 30 detected by the first detection means 100. ) Becomes a predetermined value or more, and volatile substances evaporated from ink droplets that have landed on the surface of the medium 10 are condensed and attached to the lower surface of the inkjet head 30. In order to prevent this, the inkjet head temperature adjusting means 120 is provided. The ink jet head temperature adjusting means 120 includes a comparison circuit 107 including an electronic circuit that detects a difference ΔT between the platen temperature T and the outside air temperature t, an electronic circuit built in the printer body, and the like.

  The other parts of the ink jet printer having the second volatile substance adhesion preventing mechanism shown in FIG. 4 are configured in the same manner as the ink jet printer having the first volatile substance adhesion preventing mechanism shown in FIG. Has been.

  Next, a preferred embodiment of the second volatile substance adhesion preventing method of the present invention using the second volatile substance adhesion preventing mechanism shown in FIG. 4 will be described.

  In this second volatile substance adhesion prevention method, the difference ΔT (ΔT) between the platen temperature T detected by the second detection means 102 and the outside air temperature t around the inkjet head 30 detected by the first detection means 100. = T−t) is controlled by the temperature raising unit 110 so that the volatile substance evaporated from the ink droplets that have landed on the surface of the medium 10 does not exceed a predetermined value that starts to condense and adhere to the lower surface of the inkjet head 30. The temperature rise is adjusted. Specifically, the difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection unit 102 and the outside air temperature t detected by the first detection unit 100 has reached a predetermined value. When the comparison circuit 107 detects this, the inkjet head temperature adjusting means 120 is operated, and the temperature rise of the inkjet head 30 is adjusted by the temperature raising means 110. The difference ΔT between the platen temperature T and the outside air temperature t around the inkjet head 30 becomes a predetermined value or more, and volatile substances evaporated from the ink droplets landed on the surface of the medium 10 are condensed on the lower surface of the inkjet head 30. To prevent adhesion.

  The second volatile substance adhesion preventing method includes the above steps. In the second volatile substance adhesion preventing method using the second volatile substance adhesion preventing mechanism, the second detection means is provided. When the comparison circuit 107 detects that the difference ΔT (ΔT = T−t) between the platen temperature T detected by the first detection means and the outside air temperature t detected by the first detection means has reached a predetermined value, the inkjet By operating the head temperature adjusting means 120, the temperature rise of the inkjet head 30 can be adjusted by the temperature raising means 110. Then, the difference ΔT (ΔT = T−t) between the platen temperature T and the outside air temperature t around the inkjet head becomes a predetermined value or more, and the volatile substance evaporated from the ink droplets landed on the surface of the medium 10 It is possible to prevent condensation from adhering to the lower surface of the inkjet head 30.

  FIG. 5 shows a preferred embodiment of an ink jet printer provided with a third volatile substance adhesion preventing mechanism of the present invention, and FIG. 5 is a schematic structural explanatory view thereof. Below, this 3rd volatile substance adhesion prevention mechanism is demonstrated.

  In this third volatile substance adhesion preventing mechanism, instead of the wiping means 106, the platen temperature T detected by the second detection means 102 and the outside air temperature t around the inkjet head 30 detected by the first detection means When the difference ΔT (ΔT = T−t) is equal to or greater than a predetermined value, the volatile substance evaporated from the ink droplets landed on the surface of the medium 10 is condensed and attached to the lower surface of the inkjet head 30. The platen temperature adjusting means 130 for adjusting and preventing the heating temperature of the platen 20 is provided. The platen temperature adjusting unit 130 includes a comparison circuit 107 including an electronic circuit that detects a difference ΔT between the platen temperature T and the outside air temperature t, an electronic circuit built in the printer body, and the like.

  The other parts of the ink jet printer having the third volatile substance adhesion preventing mechanism shown in FIG. 5 are configured in the same manner as the ink jet printer having the first volatile substance adhesion preventing mechanism shown in FIG. Has been.

  Next, a preferred embodiment of the third volatile substance adhesion preventing method of the present invention using the third volatile substance adhesion preventing mechanism shown in FIG. 5 will be described.

  In the third volatile substance adhesion preventing method, the difference ΔT (ΔT) between the platen temperature T detected by the second detection means 102 and the outside air temperature t around the inkjet head 30 detected by the first detection means 100. = T−t) using the platen temperature adjusting means 130 so that the volatile substance evaporated from the ink droplets that have landed on the surface of the medium 10 does not exceed a predetermined value starting to dew condensation on the lower surface of the inkjet head 30. The heating temperature of the platen 50 by the heating means 50 is adjusted. Specifically, when the comparison circuit 107 detects that the difference ΔT between the platen temperature T and the outside air temperature t around the ink jet head 30 has reached a predetermined value, the platen temperature adjusting means 130 is operated, and the heating means 50, the heating temperature of the platen 50 is lowered. The volatile substance evaporated from the ink droplets landed on the surface of the medium 10 is prevented from being condensed and attached to the lower surface of the inkjet head 30. At that time, the platen temperature adjusting means 130 prevents the heating temperature of the platen 20 by the heating means 50 from being excessively lowered. In addition, the ink droplets that have landed on the surface of the medium 10 mounted on the platen 20 are prevented from being quickly dried by the heating means 50.

  The third volatile substance adhesion preventing method includes the above steps. In the third volatile substance adhesion preventing method using the third volatile substance adhesion preventing mechanism, the second detection means is provided. The comparison circuit 107 indicates that the difference ΔT (ΔT = T−t) between the platen temperature T detected by the reference numeral 102 and the outside air temperature t around the inkjet head 30 detected by the first detection means 100 has reached a predetermined value. When this is detected, the platen temperature adjusting means 130 can be operated to lower the heating temperature of the platen 20 by the heating means 50. Then, it is possible to prevent the volatile substance evaporated from the ink droplets landed on the surface of the medium 10 from being condensed and attached to the lower surface of the inkjet head 30.

  In the first, second, or third volatile substance adhesion prevention mechanism, the first detection means 100 is a thermistor that directly detects the outside air temperature t around the inkjet head 30 and projects into the surrounding space of the inkjet head 30. It is also possible to use a thermistor provided.

The first, second, or third volatile substance adhesion prevention mechanism of the present invention and the first, second, or third volatile substance adhesion prevention method of the present invention include an ink pigment or an ink in a highly volatile organic solvent. Ink jet printers using solvent inks in which dyes are dissolved can be widely used effectively when printing pictures and / or characters for outdoor advertisements that require weather resistance and water resistance on the media surface. .
In addition, the first, second or third volatile substance adhesion prevention mechanism of the present invention and the first, second or third volatile substance adhesion prevention method of the present invention are other than the solvent ink (solvent ink). The present invention is also applicable to an ink jet printer that uses ink of a type in which a solvent evaporates when heated.

It is a schematic structure explanatory drawing of the inkjet printer provided with the 1st volatile substance adhesion prevention mechanism of this invention. 1 is a front view of a periphery of a wiper of an ink jet printer provided with a first volatile substance adhesion preventing mechanism of the present invention. It is a correlation diagram of inkjet head temperature and outside air temperature. It is a schematic structure explanatory drawing of the inkjet printer provided with the 2nd volatile substance adhesion prevention mechanism of this invention. It is a schematic structure explanatory drawing of the inkjet printer provided with the 3rd volatile substance adhesion prevention mechanism of this invention. It is a schematic structure explanatory drawing of an inkjet printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Media 20 Platen 22 Thermistor 30 Inkjet head 32 Thermistor 40 Maintenance area 50 Heating means 100 First detection means 102 Second detection means 104 Estimation means 106 Wiping means 108 Wiper 109 Inkjet head travel control means 110 Temperature rising means 120 Inkjet head temperature adjustment Means 130 Platen temperature adjusting means

Claims (7)

Ink droplets that are ejected from the nozzles on the bottom of the inkjet head that move relative to the platen surface in the X and Y directions, which are relatively parallel to the platen surface, land on the surface of the media mounted on the platen. In an inkjet printer that heats and dries by a heated means and prints a picture or character comprising an array of dots of ink , or a picture and character on the surface of a medium,
A first detection means for detecting an ambient temperature t around the inkjet head; a second detection means for detecting the platen temperature T; a platen temperature T detected by the second detection means; and the first detection means. When the difference ΔT (ΔT = T−t) from the detected outside air temperature t reaches a predetermined value or more, the lower surface of the inkjet head on which the nozzles are arranged is repeatedly wiped with a wiper every predetermined time, and landed on the media surface Volatility on the lower surface of the ink jet head of an ink jet printer, characterized by comprising wiping means for removing volatile substances that evaporate from the deposited ink droplets and condense on or adhere to the lower surface of the ink jet head Substance adhesion prevention mechanism. Ink droplets that are ejected from the nozzles on the bottom of the inkjet head that move relative to the platen surface in the X and Y directions, which are relatively parallel to the platen surface, land on the surface of the media mounted on the platen. In an inkjet printer that heats and dries by a heated means and prints a picture or character comprising an array of dots of ink , or a picture and character on the surface of a medium,
Temperature detection means for raising the temperature of the inkjet head, first detection means for detecting the outside air temperature t around the inkjet head, second detection means for detecting the platen temperature T, and detection by the second detection means. The difference ΔT (ΔT = T−t) between the platen temperature T and the outside air temperature t detected by the first detection means is equal to or greater than a predetermined value, and the volatility evaporated from the ink droplets landed on the medium surface. Ink jet of an ink jet printer, comprising: an ink jet head temperature adjusting means for preventing the material from condensing and adhering to the lower surface of the ink jet head by adjusting the temperature of the ink jet head by the temperature raising means. A volatile substance adhesion prevention mechanism on the bottom of the head. Ink droplets that are ejected from the nozzles on the bottom of the inkjet head that move relative to the platen surface in the X and Y directions, which are relatively parallel to the platen surface, land on the surface of the media mounted on the platen. In an inkjet printer that heats and dries by a heated means and prints a picture or character comprising an array of dots of ink , or a picture and character on the surface of a medium,
A first detection means for detecting an ambient temperature t around the inkjet head; a second detection means for detecting the platen temperature T; a platen temperature T detected by the second detection means; and the first detection means. The difference ΔT (ΔT = T−t) from the detected outside air temperature t becomes equal to or greater than a predetermined value, and volatile substances evaporated from ink droplets that have landed on the surface of the medium are condensed and attached to the lower surface of the inkjet head. A mechanism for preventing adhesion of volatile substances on the lower surface of an ink jet head of an ink jet printer, comprising: a platen temperature adjusting means for adjusting the heating temperature of the platen by the heating means.   The said 1st detection means consists of the thermistor which detects an inkjet head temperature, and the estimation means which estimates the external temperature t around an inkjet head from the inkjet head temperature detected by this thermistor. For preventing adhesion of volatile substances on the lower surface of an inkjet head of an inkjet printer. A method for preventing adhesion of volatile substances on the lower surface of an inkjet head of an inkjet printer using the mechanism for preventing adhesion of volatile substances on the lower surface of an inkjet head of an inkjet printer according to claim 1 or claim 1,
When the difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection means and the outside air temperature t around the inkjet head detected by the first detection means reaches a predetermined value or more. In addition, using the wiping means, the lower surface of the inkjet head on which the nozzles are arranged is repeatedly wiped with a wiper every predetermined time, and the ink droplets that have landed on the media surface evaporate and adhere to the lower surface of the inkjet head. A method for preventing adhesion of a volatile substance on the lower surface of an ink jet head of an ink jet printer, characterized by removing a volatile substance that starts to act. A method for preventing adhesion of volatile substances on the lower surface of an inkjet head of an inkjet printer using the mechanism for preventing adhesion of volatile substances on the lower surface of an inkjet head of an inkjet printer according to claim 2 or claim 2, wherein:
The difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection unit and the outside air temperature t around the inkjet head detected by the first detection unit becomes a predetermined value or more, The volatile substance evaporated from the ink droplets landed on the surface of the medium is condensed and attached to the lower surface of the inkjet head, using the inkjet head temperature adjusting means, adjusting the temperature of the inkjet head by the temperature raising means, A method for preventing adhesion of a volatile substance on the lower surface of an inkjet head of an inkjet printer. A method for preventing adhesion of volatile substances on the lower surface of an inkjet head of an inkjet printer using the mechanism for preventing adhesion of volatile substances on the lower surface of an inkjet head of an inkjet printer according to claim 3 or claim 3, wherein
The difference ΔT (ΔT = T−t) between the platen temperature T detected by the second detection unit and the outside air temperature t around the inkjet head detected by the first detection unit becomes a predetermined value or more, Adjusting the heating temperature of the platen by the heating means to prevent the volatile substances evaporated from the ink droplets landed on the surface of the medium from condensing and adhering to the lower surface of the inkjet head. A method for preventing adhesion of volatile substances on the lower surface of an inkjet head of an inkjet printer.

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