JPH11170538A - Charge control type ink jet printer and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge control ink jet printer in which mixing of inks is prevented in an ink unit when a plurality of inks are used in two color printing, or the like, and the ink can be changed easily and quickly without damaging the appearance of a printed matter. SOLUTION: A charge control ink jet printer comprising a plurality of ink units 2, and a print head 3 is further provided with a first selection means 4 for selecting the ink being fed to the print head 3 from the plurality of ink units 2, and a second selection means 5 for making a selection between returning an ink jetted from the print head 3 and collected through a gutter 35 back to a selected ink unit 2 or discharging the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge control type ink jet printer and a control method thereof, and more particularly, to changing the ink supplied from a plurality of ink units to one print head very easily and quickly. And a control method thereof.

[0002]

2. Description of the Related Art Conventionally, a charge control type ink jet printer (hereinafter, referred to as an industrial ink jet printer) has been known.
(Sometimes simply referred to as “charge control printer” or “printer”). The structure of this printer will be briefly described below with reference to FIG.

First, a solvent supplied from a solvent tank (102) through a control valve (101) and an ink tank (10) through a control valve (103).
4) is mixed with the ink supplied from the main tank (10) through the supply pump (105).
6). The ink then passes through the ink pump (107), the filter (108), and the regulator (109) in that order, and the print head (110).
Supplied to Inside the print head (110), the ink is vibrated by a piezo vibrator (111) and is ejected from a nozzle (112), and the ejected and particulated ink is charged by a charging electrode (113). Next, when printing is performed on the printing surface, the charged ink is deflected using the deflection electrode (114), and the print head (11) is deflected.
The ink is printed toward the printing surface from the slit (115) provided in 0). On the other hand, when printing is not performed on the printing surface, the charged ink is directly used as the print head (11).
0) Go straight inside and collect by gutter (116). The collected ink is returned to the ink tank (104) through the collection pump (117).

As described above, in the charge control type printer, the nozzle (112) is clogged because the ink is continuously supplied to the print head (110) regardless of the printing on the printing surface. Since the contact between the print head (110) and the printing surface can be avoided, printing can be performed regardless of the shape of the printing surface.

However, when performing printing using a plurality of inks such as two-color printing using a charge control type printer,
(1) Use two or more printers filled with different inks, or (2) First put one kind of ink into the printer and print it, then wash the entire inside of the printer and put another ink into the printer It needs to be inserted and printed again. The method (1) requires two or more printers, so that the cost is extremely high, and furthermore, there is a problem that the installation space of the printers is required by the number of printers. Further, in the method (2), since it takes time to completely clean the entire interior of the printer, it takes a very long time to replace the ink. If the ink needs to be replaced frequently, the method of (2) The method is extremely impractical. Further, when the inside of the printer is not sufficiently cleaned, there is a problem that the aesthetic appearance of the obtained printed matter is impaired due to mixing of the ink.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to mix ink in an ink unit when using a plurality of inks such as two-color printing. It is an object of the present invention to provide a charge control type ink jet printer which can prevent the appearance of printed matter and thereby change the ink extremely easily and quickly.

[0007]

In order to solve the above problems, a charge control type ink jet printer according to the present invention comprises a plurality of ink units and a print head,
First selecting means for selecting the ink supplied to the print head from a plurality of ink units, and returning or discarding the ink ejected from the print head and collected through the gutter to the selected ink unit And a second selecting means for selecting the.

[0008] In one embodiment, the above-described charge control type ink jet printer is provided with air bleeding means on its print head, and transfers ink collected from the print head via the air bleeding means to a selected ink unit. A third selecting means for selecting whether to return or discard may be provided.

According to another aspect of the present invention, there is provided a method for controlling a charge control type ink jet printer, comprising the steps of: (a) operating a first selecting means to supply ink supplied to a print head to a plurality of ink units; (B) ejecting the ink supplied to the print head from the ejection unit, collecting ink not used for printing via the gutter, and operating the second selection means via the gutter. Returning the collected ink to the selected ink unit and circulating the ink in the charge control type ink jet printer; (c) operating the first selecting means to reduce the ink supplied to the print head to the step (a). (D) selecting from ink units other than the ink unit selected in (d); (d) using the ink supplied to the print head in step (c). Washing the lint head and operating the second selection means to discard the ink that has been washed inside the print head; and (e) ejecting the ink supplied to the print head from the ejection unit after the washing is completed. Then, while collecting the ink not used for printing through the gutter, operating the second selecting means to return the ink collected through the gutter to the ink unit selected in the step (c), Circulating the ink in a charge-controlled inkjet printer.

The print head further includes an air bleeding means, and a third selection means for selecting whether the ink collected from the print head via the air bleeding means is returned to the selected ink unit or discarded. When a charge control type ink jet printer equipped with a printer is used, the method for controlling the printer is as follows: (a) operating the first selecting means to select the ink to be supplied to the print head from a plurality of ink units; (B) ejecting the ink supplied to the print head from the ejection unit, collecting ink not used for printing via the gutter, operating the second selection unit, and collecting the ink via the gutter. Is returned to the ink unit selected in step (a), and the third selecting means is operated to remove air from the print head through the air bleeding means. Returning the collected ink to the selected ink unit, and circulating the ink in the charge control type ink jet printer; (c) operating the first selecting means to reduce the ink supplied to the print head; A step of selecting from ink units other than the ink unit selected in (a); (d) washing the inside of the print head with the ink supplied to the print head in step (c), and operating the second selecting means to perform printing Discarding the ink that has washed the inside of the head and discarding the ink collected from the printhead via the air bleeding means by operating the third selection means; and (e) printing the printhead after the washing is completed. The supplied ink is ejected from the ejecting unit, and the ink not used for printing is collected through the gutter, and the second selection unit is operated to play the ink. The ink collected through step (c) is returned to the ink unit selected in step (c), and the ink collected from the print head via the air venting means is operated by operating the third selection means. Returning to the selected ink unit and circulating the ink in the charge-controlled inkjet printer.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a charge control type ink jet printer (1) according to the present invention.
A plurality of ink units (2), a print head (3), first selection means (4) for selecting ink supplied to the print head (3) from the plurality of ink units (2), The second selection for selecting whether to return the ink jetted from the jetting unit (31) and collected through the gutter (35) through the gutter (35) to the predetermined ink unit (2) selected above or to discard the ink. Means (5).

(Regarding Ink Unit (2)) As shown in FIG. 2, the ink unit (2) includes a main tank (21), a solvent tank (22) for storing a solvent, and an ink tank (23) for storing ink. A filter (24) for removing dust in the ink supplied to the print head (3), a regulator (25) for adjusting the pressure of the ink supplied to the print head (3), and the like. Hereinafter, the present invention will be described in detail focusing on the flow of ink in such a printer (1).

First, as shown in FIG. 2, an ink tank (23) passes through an open control valve (231).
Is supplied from the solvent tank (22) through the control valve (221) while being sucked by the supply pump (27), and flows into the main tank (21). When the printer (1) according to the present invention is not used, the control valve (22) is not used.
1) The flow of the ink is stopped by closing (231).

Next, the ink that has flowed into the main tank (21) is sucked by an ink pump (28), passes through a filter (24) to remove solid debris, and then passes through a regulator (25). The pressure and the like are adjusted to a predetermined pressure and head toward the print head (3) (FIGS. 1 and 2).
"A"). In order to check whether the fluid pressure is adjusted to a predetermined pressure, a regulator (2)
Preferably, a pressure gauge (29) is provided behind 5).

In this way, as shown in FIG. 1, the ink from the plurality of ink units (2) to the print head (3) reaches the first selecting means (4). In the first selecting means (4), of the inks directed from the plurality of ink units (2) to the print head (3), only one of the inks flows to the print head (3), and the other inks Flow is blocked. That is,
The first selecting means (4) allows only one of the inks directed from the plurality of ink units (2) to the print head (3) to flow to the print head (3), and the other inks It is a means to block the flow. The ink whose flow has been blocked by the first selecting means (4) is returned to the ink tank (23) through the valve (91) (see "B" in FIGS. 1 and 2). In the ink unit (2) not selected by the first selection means (4), unless the clogging occurs in the piping,
The control valves (221) and (231) are closed to stop the flow of the ink in the ink unit (2).
You may open 1).

The structure of the first selecting means (4) is, for example, as shown in FIG.
1) (42) is connected to each ink unit (2), and the print head (3) is connected through the valves (41) and (42).
And a structure in which the flow pipes extending to each other are integrated.
In addition to the structure shown in the figure, a multi-way valve such as a three-way valve is also used. In addition, it is preferable to use an electromagnetic valve as the valves (41) and (42), from the viewpoint that remote operation is easy and the fluid flow can be reliably prevented. By using such a first selecting means (4), it is not necessary to use two or more printers in which different inks are supplied, and it is not necessary to replace the ink in the ink unit (2).

Next, as described above, the print head (3)
Is ejected from the nozzle (311) at the tip of the ejector (31) provided with a piezo oscillator (not shown) while being vibrated by the piezo oscillator and becomes particles. When printing is performed, the ink that has been made into particles is charged using the charging electrode (32) provided in front of the nozzle (311), and then the deflection electrode (33) provided in front of the charging electrode (32) is charged. Deflects the charged ink by using the slit (3) provided in the print head (3).
Printing is performed by injecting from 4) to the outside. On the other hand, when printing is not performed, the ink is not charged, or even if the ink is charged, the deflection electrode (3) is not charged.
The ink is collected in a gutter (35) by ejecting the ink linearly without applying a voltage to 3). In addition, at the time of collection, it is preferable to perform collection while suctioning with a collection pump (92) provided behind the gutter (35) in order to perform collection more reliably.

The ink not used for printing and collected by the gutter (35) reaches the second selecting means (5).
In the second selecting means, it is selected whether the collected ink is returned to the ink unit (2) selected in the first selecting means (4) or discarded. That is,
The second selecting means (5) is a means for selecting whether to return the collected ink to the ink unit (2) selected by the first selecting means (4) or to discard it. In addition, in the second selecting means (5), the collected ink does not flow to the ink unit (2) not selected by the first selecting means (4). This is because if ink flows into such an ink unit (2), the ink unit (2) not selected by the first selection unit (4) differs (especially, inside the ink tank (23)). This is because the ink is mixed.

The ink returned to the ink unit (2) selected by the first selecting means (4) by the second selecting means (5) passes through the valve (51 or 52) and is supplied to the ink unit (2). It is returned to the tank (23) and reused (see "D" in FIGS. 1 and 2). That is, the ink continuously circulates inside the printer (1) in this manner. Therefore, clogging (in particular, clogging in the nozzle (311)) due to the stoppage of the flow of ink does not occur. Since the ink is returned to the ink tank (23) and reused as described above,
In some cases, the concentration of the ink in the ink tank (23) may not be constant. In this case, the amount of the solvent flowing from the solvent tank (22) is adjusted to reduce the concentration of the ink in the main tank (21). Can be kept constant.

The ink discarded by the second selecting means (5) passes through the valve (53 or 54) in FIG.
The waste is discarded in the flocculation tank (26) provided in the ink unit (2) selected by the first selecting means (4) (see "E" in FIGS. 1 and 2). The coagulation tank (26) does not necessarily need to be provided for each ink unit (2), and the discarded ink may be discarded in one coagulation tank. It need not be built in the unit (2).

The structure of the second selection means (5) is, for example, as shown by a dotted line B in FIG. 1, connected to one flow pipe extending from the print head (3), and further comprising a plurality of valves. (51 to 54) with the ink unit (2)
Connected to the ink tank (23) and the aggregation tank (26). Similarly to the first selection means (4), a multi-way valve such as a three-way valve is also used, and a solenoid valve is preferable as the valve.

In order to stabilize the ink inside each tank by keeping the pressure inside each tank in the ink unit (2) constant, a pressure pipe (2) shown by a dotted line in FIG.
0) is preferably provided inside the ink unit (2), but in order to stabilize the ink in the coagulation tank (26), the pressure tube (26) is also provided in the coagulation tank (26) as shown in FIG. 20) are preferably connected. For this reason, the coagulation tank (26) is preferably provided inside the ink unit (2). Also, a pressure pipe (20)
Is connected to each ink unit (2), and the pressure inside any of the ink units (2) is preferably kept constant.

Next, a case where the used ink is switched will be described. In the following description, ink that is no longer flown to the print head (3) by switching is ink A, ink that is flown is ink B, and ink unit (21) corresponding to ink A is ink unit A (21).
A, the ink unit on the left side in FIG. 1), and the ink unit (21) corresponding to the ink B in the same manner as the ink unit B (21B, the right ink unit in FIG. 1).

When switching the ink used for printing, first, the first selecting means (4) is operated to operate the valve (41).
By closing the valve and opening the valve (42),
The ink flowing to the print head (3) is switched from ink A to ink B. The fluid tube, the print head (3), and the like after the first selection means (4) are filled with the ink A, but the first selection means (4) is operated as described above to perform the first selection. The ink B flows through the flow tube and the like after the means (4). Also, almost simultaneously with switching the first selection means (4), only the valve (53) was opened from the state where only the valve (51) was opened, and the other valves (51, 52, 54) were closed. The second selection means (5) is operated so as to be in the state. Then, from the first selecting means (4) including the print head (3), the second
Up to the selection means (5), the ink B starts flowing and the ink A and the ink B are mixed during this time. The mixed ink is supplied to the valve (5) by the second selection means (5).
It is discarded by flowing through 3) to the flocculation tank (26).

Further, the ink units B (21)
Since the ink B flows from B), the ink A is washed by the ink B in the piping (including the print head 3) from the first selecting means (4) to the second selecting means (5). . Further, the cleaning liquid thus cleaned (that is, the ink B used for cleaning the ink A)
Is discarded by being flowed toward the coagulation tank (26) by the second selecting means (5).

After the washing is completed, the ink in the pipe from the first selecting means (4) to the second selecting means (5) is changed to the ink A.
After completely replacing the ink with the ink B, the valve (53)
The second selection means (5) is operated such that only the valve (52) is opened from the state where only the valve is opened, and the other valves (51, 53, 54) are closed. Then, the ink B that has passed through the second selecting means (5) flows to the ink unit B (21B), whereby the ink B circulates inside the printer (1). In addition,
Whether the ink in the pipe from the first selecting means (4) to the second selecting means (5) has been completely replaced by the ink A by the ink B by the washing is determined by the second selecting means (5).
The ink flowing in the vicinity may be actually checked, or the time when the ink is completely replaced is measured for each device, and after a predetermined time has passed, it is considered that the ink has been completely replaced, and the second selection is performed by a timer (not shown). The means (5) may be controlled.

As described above, in a case where a plurality of inks such as two-color printing are used by using a charge control type printer,
First selecting means (4) for selecting the ink to be used from the plurality of ink units (2) between the plurality of ink units (2) and the ejection section (31) of the print head (3);
And a second selection means (5) between the gutter (35) of the print head (3) and the plurality of ink units (2) for returning or discarding ink to the predetermined ink unit (2). This not only does not require a plurality of printers, but also ensures that different inks are not mixed inside the ink unit (2) and that the ink unit (2)
The ink used for printing can be changed very easily and quickly without replacing the ink inside and cleaning the ink unit (2) accompanying the replacement. In addition, since the ink continuously passes through the print head (3) both at the time of printing and at the time of ink replacement, it is possible to prevent clogging of the nozzles (311) even at the time of ink replacement, It is not necessary to stop the operation of the printer (1).

Further, the ejection part (3) of the print head (3)
If the ink that has reached 1) contains bubbles, the ink at the front of the ejection section (31) is compressed by a piezoelectric vibrator (not shown) provided in the ejection section (31) to eject the ejection section (31). 3
When the ink is ejected from 1), the ink is not compressed and the air bubbles are compressed, so that the ink may not be ejected, or even if the ink is ejected, the ink may not be turned into particles. Therefore, it is preferable that the print head (3) is provided with an air bleeding unit (not shown) for removing air bubbles of the ink that has reached the ejection unit (31).
In this case, a third selection is made to select whether to return the ink collected from the print head (3) via the air release means to the ink unit (2) selected by the first selection means (4) or to discard the ink. It is preferable to have a selection means (6).

As the third selecting means (6), similarly to the second selecting means (5), a structure in which a plurality of valves (61 to 64) are combined as shown by a dotted line C in FIG. The flow of the ink is almost the same as that of the second selecting means (5), and the ink collected from the jetting part (31) through the air bleeding means (not shown) is used except when the ink is switched. Is passed through the third selecting means (6) in a state where only one of the valves (61) and (62) is opened and the other valves are closed, so that the first selecting means (4) The ink is returned to the main tank (23) of the selected ink tank (2) (see “C” in FIGS. 1 and 2). On the other hand, when the ink is switched, the third selector (6) is operated so that the valve (63) or (64) is opened and the other valves are closed, and the ink is recovered. The ink is discarded by flowing toward the coagulation tank (26) (FIG. 1).
And "E" in FIG. 2).

By using the third selecting means (6), the collected ink is reused during printing,
The ink is discarded during ink replacement. Thus, regardless of the presence of air bubbles in the ink that has reached the ejection section (31) of the print head (3), a plurality of printers are not required, and different inks are used inside the ink unit (2). Are not mixed, and the ink can be continuously passed through the print head (3) both at the time of printing and at the time of ink replacement.
The clogging of 1) can be prevented.

In FIG. 1, two ink units (2) and four valves (51, etc.) are shown for illustration, but the number of ink units (2),
It goes without saying that the number of valves (such as 51) is not limited to the number shown in the drawings. Further, the first selecting means (4), the second selecting means (5), and the third selecting means (6) are independent of the ink unit (2) and the print head (3) as shown in FIG. Well or
It may be built in the ink unit (2) or the print head (3).

[0032]

According to the present invention, when a plurality of inks are used for two-color printing or the like, different inks are not mixed inside the ink unit (2), and the ink is exchanged inside the ink unit (2). Provided is a charge control type ink jet printer capable of changing ink used for printing very easily and quickly without washing the ink unit (2) accompanying the replacement, and a control method therefor.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flow of ink in a printer (1) according to the present invention.

FIG. 2 is a diagram showing a flow of ink inside an ink unit (2). The alphabets A to E in FIG. 1 are connected to the alphabets A to E in FIG. 2, respectively.

FIG. 3 is a diagram used to explain a basic structure of a conventional charge control type printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charge control type printer 2 Ink unit 20 Pressure pipe 21 Main tank 22 Solvent tank 221 Control valve 23 Ink tank 231 Control valve 24 Filter 25 Regulator 26 Coagulation tank 27 Supply pump 28 Ink pump 29 Pressure gauge 3 Print head 31 Injection part 311 nozzle 32 Charged electrode 33 Deflection electrode 34 Slit 35 Gutter 4 First selection means 41 Valve 42 valve 5 Second selection means 51 Valve 52 Valve 53 Valve 54 Valve 6 Third selection means 61 Valve 62 Valve 63 Valve 64 Valve 91 Valve 92 Recovery pump 101 control valve 102 solvent tank 103 control valve 104 ink tank 105 supply pump 106 main tank 107 ink port Pump 108 Filter 109 Regulator 110 Printhead 111 Piezoelectric transducer 112 Nozzle 113 Charging electrode 114 Deflection electrode 115 Slit 116 Gutter 117 Collection pump

Claims (4)

[Claims] 1. A charging control type ink jet printer having a plurality of ink units and a print head, wherein: a first selecting means for selecting ink supplied to the print head from the plurality of ink units; Control means for selecting whether to return the ink ejected from the gutter and collected through the gutter to the selected ink unit or to discard it. 2. A method according to claim 2, wherein said print head is provided with an air vent means, and said ink collected from said print head via said air vent means is returned to said selected ink unit or discarded. 2. The charging control type ink jet printer according to claim 1, further comprising three selection means. 3. The control method for a charge control type ink jet printer according to claim 1, which includes the following steps: (a) operating the first selecting means to cause the ink supplied to the print head to A step of selecting from a plurality of ink units; (b) ejecting the ink supplied to the print head from an ejection unit, collecting ink not used for printing via the gutter, and the second selecting unit. (C) returning the ink collected through the gutter to the ink unit selected in step (a), and circulating the ink in the charge control type ink jet printer; (c) the first selection Operating the means to select ink supplied to the print head from ink units other than the ink unit selected in step (a); (d) step washing the inside of the print head with the ink supplied to the print head in c), and discarding the ink that has been washed inside the print head by operating the second selecting means; and (e) washing the ink. Is completed, the ink supplied to the print head is ejected from an ejection unit, ink not used for printing is collected through the gutter, and the gutter is operated by operating the second selection unit. Returning the ink recovered through the ink unit selected in step (c), and circulating the ink in the charge control type ink jet printer. 4. The method of controlling a charge control type ink jet printer according to claim 2, comprising the following steps: (a) operating the first selecting means to cause the ink supplied to the print head to Selecting from a plurality of ink units; (b) ejecting the ink supplied to the print head from an ejection unit, collecting ink not used for printing through the gutter, and setting the second selection unit to The ink collected by way of the gutter is returned to the ink unit selected in the step (a), and the third selection means is operated to recover the ink collected from the print head via the air release means. Returning the ink to the selected ink unit and circulating the ink in the charge-controlled ink jet printer; (c) operating the first selecting means to Selecting the ink supplied to the print head from the ink units other than the ink unit selected in the step (a); (d) using the ink supplied to the print head in the step (c) to clean the inside of the print head. Washing and operating the second selecting means to discard the ink that has washed the inside of the print head, and operating the third selecting means to remove the ink collected from the print head through the air venting means. And (e) ejecting the ink supplied to the print head from an ejection unit after the washing is completed, collecting ink not used for printing through the gutter, and performing the second selection. Operating the means to return the ink collected through the gutter to the ink unit selected in step (c), and operating the third selecting means to remove the ink from the print head. Serial return the ink recovered through the air vent means in the ink unit which is the selected, the step of circulating the ink in the charging controlled within an inkjet printer.