JP2012096497A - Inkjet recording device - Google Patents

Abstract

In a continuous discharge type ink jet recording apparatus that charges and deflects ink particles and prints on a printing object, a device that arbitrarily adjusts a gap of each printing area printed by each nozzle is made smaller than a printing unit. To do.
An ink container that stores ink, a supply pump that supplies ink to a nozzle, a nozzle that ejects ink to form ink particles, a charging electrode that charges ink particles, and a deflection that deflects ink particles In an inkjet recording apparatus having an electrode and a gutter for collecting ink particles, it has at least two printing units comprising a nozzle, a charging electrode, a deflection electrode, and a head substrate that supports the gutter, and the ink ejection direction and printing of one printing unit A discharge direction setting device for variably positioning the area with respect to another printing unit is provided.
[Selection] Figure 6

Description

  The present invention relates to a continuous discharge type ink jet recording apparatus that performs printing on an object to be printed by ejecting ink from nozzles.

  Regarding a conventionally known background art relating to this technical field, Patent Document 1 discloses that in a continuous discharge type ink jet recording apparatus having a plurality of nozzles, ink droplets are deflected in the sub-scanning direction and the mounting direction of each nozzle 21 is adjusted in the sub-scanning direction. A configuration is disclosed in which the ink ejection position in the main scanning direction is adjusted by controlling the ink ejection timing and the delay amount of the image signal applied to the charging electrode 44, and omitting the mechanical adjustment. Further, in Patent Document 2, in an on-demand type droplet jet patterning apparatus, a plurality of supports each rotatably supporting a nozzle head, and the nozzle head is parallel to the droplet discharge direction with respect to each support and A plurality of rotation drive servomotors each capable of being driven to rotate about an axis orthogonal to the direction in which the nozzles are arranged; a plurality of slide mechanisms for supporting the plurality of supports so as to be slidable in the sub-scanning direction; A configuration provided with a plurality of position adjustment drive mechanisms is disclosed.

JP-A-8-142332 JP 2003-173874 A

  In Patent Document 1, each of the plurality of nozzles has an ejection angle adjustment mechanism with respect to the base, and the deviation of the printing position by each nozzle is corrected. However, a deflection electrode for deflecting charged ink particles and a gutter for collecting ink are provided. Since it is fixed to the common base, the print area formed by the specific nozzle cannot be moved relative to the print area of the other nozzles in the sub-scanning direction (deflection direction). For this reason, the gap between the print areas could not be adjusted.

  In Patent Document 2, when adjusting the resolution of an apparatus, a print area is moved by combining a plurality of nozzles of a nozzle head with a rotation mechanism and a slide mechanism. However, in this configuration, the print area for each nozzle head is not adjusted, the print head that supports the nozzle head and performs printing becomes larger, and the print head can be brought closer to the printing object in a place where the periphery of the printing object is complicated. In some cases, printing was not possible.

  The present invention includes a print head that performs printing on a printing material, and includes a plurality of printing units that have nozzles, charging electrodes, deflection electrodes, and gutters and that eject ink particles onto the printing material. In the continuous discharge type ink jet recording apparatus, each of the plurality of print units has a print area on the print object, and at least one ink discharge shaft of the print unit is connected to the discharge shaft of another print head on the print head. A discharge direction setting device is provided to change the position of the print area on the print object of the plurality of print units.

  In the continuous discharge type inkjet recording apparatus, at least one of the printing units is pivotally supported with respect to the printing head.

  In the continuous discharge type ink jet recording apparatus, the discharge direction setting device includes a fixing unit that rotatably supports and fixes the print unit in the print head.

  In the continuous discharge type ink jet recording apparatus, the printing unit has the nozzle, the charging electrode, the deflection electrode, and the gutter mounted on a head substrate, and at least one of the printing units is rotated on the head substrate of another printing unit. It is characterized by being pivotally supported.

  In the continuous discharge type ink jet recording apparatus, an angle adjusting means for adjusting an ink discharge angle of at least one of the printing units is provided.

  Further, in the continuous discharge type ink jet recording apparatus, at least two ink discharge shafts of the printing unit are included in a plane parallel to each other and are in a twisted positional relationship.

  Further, the continuous discharge type inkjet recording apparatus has a branch path for distributing the ink supplied from the supply pump to at least two of the print units, and the branch path is on the head substrate of one of the two print units. It is characterized by being arranged in.

  In the continuous discharge type ink jet recording apparatus, an opening / closing valve is provided on at least one of the branch paths.

  In the continuous discharge type inkjet recording apparatus, a shielding member having a ground potential is provided between at least two of the printing units.

  Further, the continuous discharge type ink jet recording apparatus is characterized in that each printing unit has at least two printing units and a detection sensor for detecting a printed matter corresponding to the printing units.

  The present invention relates to a continuous discharge type ink jet recording apparatus in which a plurality of printing units each having a nozzle, a charging electrode, a deflection electrode, and a gutter are mounted on a print head, and each of the plurality of printing units has a print area on a printing object. , A discharge direction setting device for changing at least one ink discharge axis of the print unit with respect to the discharge axis of another print head, and a plurality of nozzles having nozzles by changing the position of the print area on the substrate The ink jet recording apparatus can be provided in which each print area formed on the substrate by the print unit is relatively moved, and the print area can be moved significantly with respect to the movement of the print unit.

  Furthermore, it is possible to provide an ink jet recording apparatus that can arbitrarily adjust the interval between the print areas by adjusting the position of each print unit and obtain an optimum print result.

1 is a perspective view of an ink jet recording apparatus of the present invention. It is a schematic longitudinal cross-sectional view of the inkjet recording device main body of this invention. 1 is a perspective view of a printing system of an ink jet recording apparatus of the present invention. It is a schematic block diagram which shows the flow-path system | strain of the ink of this invention, and solvent gas. It is a block diagram which shows the control system of the inkjet recording device of this invention. It is a horizontal sectional view of the print head of the present invention. FIG. 3 is a vertical sectional view of the print head of the present invention. FIG. 7 is a longitudinal sectional view taken along line AA in FIG. 6. It is a side view of the rotation adjustment mechanism of the print head of the present invention. It is a schematic diagram of a print sample at the time of four-line printing at a rotation angle of 0 ° according to the present invention. It is a schematic diagram of a print sample at the time of two-line printing at a rotation angle of 0 ° according to the present invention. It is a schematic diagram of a print sample at the time of two-line printing at a rotation angle of 0 ° according to the present invention. It is a schematic diagram of the printing sample at the time of two line printing at the time of rotation of this invention.

  Hereinafter, examples will be described with reference to the drawings.

[Basic configuration]
First, the external configuration of the ink jet recording apparatus according to the present invention will be described with reference to FIG. The ink jet recording apparatus includes a main body 600 that houses a control system and a circulation system, a print head 610 that performs printing, and a cable 620 that connects the main body 600 and the print head 610. The main body 600 has a touch panel type liquid crystal panel 630 on which a user can input printing contents, printing specifications, etc., and display control contents, apparatus operating conditions, and the like.

  The cable 620 is generally 2 to 6 m in length, and in the cable 620, a signal cable for connecting the print head 610 and the main body 600 and a tube for passing ink and solvent are housed.

  The print head 610 is covered with a stainless steel head cover 615 and includes a head substrate 100B to which a cable 620 is connected. Inside the print head 610, there are two print heads that perform printing by ejecting ink particles. The head cover 615 has two slits 640A and 640B through which ink particles used for printing can pass.

Next, the internal configuration of the main body 600 of the ink jet recording apparatus will be described with reference to FIG. Electrical parts such as a control circuit 645 are arranged in the upper part of the main body 600. The lower part of the main body 600 is separated by a partition wall 665. Circulating system control parts such as a solenoid valve unit 650 and a pump unit 655 are arranged in the lower part 680, and ink storing ink used for printing is arranged in the lower part 660. Circulating system parts such as a container 1, a solvent container 16 that stores an ink solvent, and a concentration meter (not shown) that detects an ink concentration in the ink container 1 are housed. By opening the door 670, the ink container 1 and the solvent container 16 can be pulled out from the main body 600, and it is configured to facilitate maintenance such as replenishment and disposal of ink and solvent.
[Printing system configuration]
Next, a configuration example of a printing system that performs printing using the ink jet recording apparatus according to the present embodiment will be described with reference to FIG.

The belt conveyor 55 conveys the printing objects 500A, 500B, and 500C in the main scanning direction (X direction). The print head 610 performs printing by ejecting ink particles, and is supported and fixed by a column or the like so that printing can be performed on the printing objects 500A, 500B, and 500C that cross the print head 610 in order. A desired print is performed on the print areas 700A and 700B on the object to be printed 500A across the print head 610 by the ink particles discharged in the Z direction (discharge direction) from the print head 610. The print areas 700A and 700B are arranged in the sub-scanning direction (Y direction) orthogonal to the main scanning direction (X direction). The timing of printing is determined by the detection sensor 671 for the printing object 500 disposed upstream of the position where printing is performed. Note that at least one detection sensor 671 may be provided. It is also possible to provide a detection sensor corresponding to each printing unit and control printing at different timings in each printing unit. It is also possible to print on a different printing object for each printing unit.
[Flow path system]
Next, the flow path system and recording operation of the ink jet recording apparatus according to the present invention will be described with reference to FIG. In this apparatus, as a flow path for ink and solvent, an ink supply flow path 21 that supplies ink in the ink container 1 to the switching valve 32, and an ink collection flow path 22 that collects ink that is not used for printing in the ink container 1. There are a solvent supply channel 23 for supplying the solvent in the solvent container 16 to the switching valve 32 and a supply channel 27 for supplying ink or solvent from the switching valve 32 to the nozzles 6A and 6B.

  The switching valve 32 is a three-way solenoid valve. When energized: Open / not energized: The ink supply flow path 21 is in the normally closed port that is closed, and when energized: Closed / not energized: the solvent is supplied to the normally open port that is open A supply flow path 27 is connected to the common port of the flow path 23 when energized: open / non-energized: open. The supply channel 27 is branched into supply channels 27A and 27B. The supply channel 27A is connected to the nozzle 6A, and the supply channel 27B is connected to the nozzle 6B. Therefore, by switching the switching valve 32, the ink and the solvent can be switched and supplied to the nozzles 6A and 6B. Here, on-off valves may be provided in the supply channels 27A and 27B, respectively, so that ink or solvent is supplied to only one of the nozzles.

  As shown in FIG. 4, the solvent supply flow path 23 includes a solvent pump 15 that pumps the solvent, and a solvent valve 31 that is a two-way electromagnetic valve that opens and closes the flow path. Supply to 32 normally open ports. Therefore, when the solvent valve 31 is energized and the switching valve 32 is not energized, the solvent is supplied to the nozzles 6A and 6B, and the solvent is ejected from the orifice holes of the nozzles 6A and 6B. In general, the orifice hole diameter in this apparatus is 30 to 200 μm, and in this embodiment, the nozzles 6A and 6B are both orifice holes having an inner diameter of 65 μm. Moreover, the solvent pump 15 used the diaphragm pump which can pressurize a solvent to 0.3 Mpa or more. The solvent ejected from the nozzle 6A travels straight, flies through the discharge shaft 12A to the gutter 11A, and the solvent ejected from the nozzle 6B flies through the discharge shaft 12B and is collected in the gutter 11B. The discharge shafts 12A and 12B are in the Z direction. This operation is mainly performed when preventing clogging due to ink sticking around the nozzles 6A and 6B, particularly around the orifice hole, or when the ink in the ink container 1 is diluted. In this embodiment, the solvent container 16 is provided with a vapor discharge channel 25 for discharging the solvent gas evaporated in the solvent container 16 to the outside of the main body 600.

As shown in FIG. 4, in the ink supply channel 21, a supply pump 2 that pumps ink in the ink container 1, a supply valve 33 that is a two-way electromagnetic valve that opens and closes the channel, a filter 5, and an ink pressure are adjusted. There are a pressure regulating valve 3 for controlling the pressure, and a pressure gauge 4 for measuring the pressure of the supplied ink. When the supply valve 33 and the switching valve 32 are energized, ink is supplied to the nozzles 6A and 6B, and ink is ejected from the orifice holes of the nozzles 6A and 6B. The supply pump 2 uses a diaphragm pump that can pressurize the ink to 0.3 MPa or more, and the pressure regulating valve 3 adjusts the ink pressure to 0.25 MPa.
[Printing principle]
Next, the printing principle of the ink jet recording apparatus will be described with reference to FIG. 4 again. In this embodiment, the print head 610 has two sets of print units 610A and 610B that perform printing, and the configuration and printing principle of the print units 610A and 610B are the same.

  The printing unit 610A includes a nozzle 6A, a charging electrode 7A, a deflection electrode 9A, and a gutter 11A. First, the ink supplied under pressure by the supply pump 1 is ejected from the nozzle 6A by a piezoelectric actuator (not shown) whose vibration is controlled by the excitation source 370 and then ejected from the nozzle 6A at a constant cycle rate. It becomes. The atomized ink particles 8A are ejected in the Z direction, charged by the recording signal by the charging electrode 7A, and then fly in the deflection electric field where the Lorentz force in the Y direction acts. The deflection electric field is formed between the high-voltage electrode 9A to which a high voltage of 5 to 6 kV is applied and the grounded ground electrode 10A, and the charged ink particles 8D are deflected in the Y direction according to the charge amount. Then, the ink is discharged from the print head 610 through the slit 640A.

  Similarly, the printing unit 610B includes a nozzle 6B, a charging electrode 7B, a deflection electrode 9B, and a gutter 11B. First, ink supplied under pressure by the supply pump 1 is atomized in the nozzle 6B at a constant cycle rate after being ejected from the nozzle 6B by the excitation of the piezoelectric actuator whose vibration is controlled by the excitation source 370. The atomized ink particles 8B are ejected in the Z direction, charged by a recording signal by the charging electrode 7B, and then fly in a deflection electric field where a Lorentz force in the Y direction acts. The deflection electric field is formed between the high voltage electrode 9B to which a high voltage of 5 to 6 kV is applied and the ground electrode 10B that is grounded, and the charged ink particles 8F are deflected in the Y direction according to the charge amount. Then, the ink is ejected from the print head 610 through the slit 640B, and is attached to the print object 500 at a distance L from the print head 610 to form a print dot.

  The size of the printing dot in this embodiment is 0.3 to 0.4 mm. With respect to the deflection amount of the ink particles, the print dot row arranged in the Y direction can be formed in the print areas 700A and 700B by sequentially increasing the charge amount. The print areas 700A and 700B are the ranges in the Y direction in which the ink particles 8D and 8F can adhere on the print substrate 500.

  In the ink jet recording apparatus of the present embodiment, printing is possible in the charging voltage range of 90 to 360 V, and the printing units 610A and 610B have the same specifications. Therefore, when L = 15 mm, the printing areas 700A and 700B have a maximum of 10 mm ( Y direction).

  Since the object to be printed 500A is conveyed in a direction substantially perpendicular to the sub-scanning direction Y (main scanning direction X), a character composed of a two-dimensional dot matrix in the sub-scanning direction Y and main scanning direction X is printed. it can. Since the ink particles 8C and 8E that are not used for printing are not charged, the ink particles 8C and 8E travel straight without being deflected and are taken into the gutters 11A and 11B along the discharge shafts 12A and 12B.

  In this embodiment, in the printing units 610A and 610B, the component nozzles 6A and 6B, the charging electrodes 7A and 7B, the deflection electrodes 9A and 9B, and the gutters 11A and 11B have the same specifications, and the same charging voltage and deflection voltage are used. If given, characters of the same height can be printed on the substrate 500. However, by changing the specifications of the nozzle, charging electrode, deflection electrode, voltage, etc., it is possible to print with printing dot diameters of 200, 350, 500 microns, etc. Can be printed at the same time.

  As shown in FIG. 4, the ink recovery channel 22 has a filter 13 that removes foreign matters mixed during ink recovery, a recovery pump 14 that generates negative pressure in the gutters 11A and 11B, and a recovery that opens and closes the ink recovery channel. There is a valve 34, which is connected to the ink recovery flow paths 22A and 22B in the print head 610. The ink recovery channels 22A and 22B have phase sensors 60A and 60B, and are connected to the gutters 11A and 11B. The recovery valve 34 is a two-way electromagnetic valve, and is open when energized during ink recovery. The ink taken in by the gutters 11 </ b> A and 11 </ b> B is collected by the collection pump 14 into the ink container 1 through the ink collection channels 22 </ b> A, 22 </ b> B, and 22.

The recovery pump 14 used in the present embodiment is a diaphragm pump and can be sucked at an air flow rate of 200 ml / min or more, so that it can be recovered in the ink container 1 without leaking liquid such as ink or solvent from the gutters 11A and 11B. In the present embodiment, Teflon (registered trademark of DuPont) tubes having a tube inner diameter of 2 mm are used for the ink recovery channels 22, 22A, 22B.
[Control circuit]
Next, the control circuit 645 of the ink jet recording apparatus according to the present invention will be described with reference to FIG. The CPU 300 is a central processing unit that controls the ink jet recording apparatus according to this embodiment. The ROM 310 is a read-only memory that stores programs and control data necessary for the CPU 300 to operate. The RAM 305 is a rewritable memory that temporarily stores data and the like handled by the CPU 300 during program execution. The bus line 380 is a signal line including all data, address signals, and control signals from the CPU 300. The interface circuit 315 mediates input / output of data, address signals, control signals, and the like.

  The pump control circuit 320 controls the operation of pumps such as the supply pump 2 and the recovery pump 14 in the pump unit 655 based on a command from the CPU 300. The density detection circuit 335 controls the operation of ink density detection in the ink container 1 based on a command from the CPU 300 and measures the ink density. The electromagnetic valve control circuit 340 controls the operation of all the electromagnetic valves such as the supply valve 33 and the recovery valve 34 in the electromagnetic valve unit 650 based on a command from the CPU 300.

  The excitation source 370 generates an excitation signal based on the nozzle operation conditions, and drives a piezoelectric actuator (not shown) for particle formation. The phase detection circuit 330 receives signals from the phase sensors 60A and 60B that detect the charge amounts of the ink particles collected by the gutters 11A and 11B, determines the phase timing of the recording signal, and stores it in the RAM 305. The printed material detection circuit 345 sends a detection signal from the detection sensor 671 to the CPU 300, and determines a print start timing for printing in a predetermined print area from the detection signal, the phase timing, and the set delay time.

The recording signal source 360 creates a recording signal for each ink particle and printing presence / absence information based on the input printing data, stores it in the RAM 305, and applies the recording signal to the charging electrodes 7A and 7B based on the printing start timing.
[Internal structure of print head]
Next, details of the inside of the print head 610 will be described with reference to FIGS. 6, 7, and 8. Inside the print head 610, two print units 610A and 610B for ejecting ink particles for printing are mounted. The print unit 610A is mounted on the head substrate 100A, and the print unit 610B is mounted on the head substrate 100B. The details will be described.

  On the surface side of the head substrate 100A, a nozzle 6A, a charging electrode 7A, a deflection electrode 9A, and a gutter 11A are fixed to form a printing unit 610A. A phase sensor 60A and an ink recovery channel 22A are fixed to the back side of the head substrate 100A and covered with a protective cover 101A. The ink recovery channel 22A passes through the tube 31 connecting the head substrate 100A and the head substrate 100B, and is connected to the ink recovery channel 22 on the back surface side of the head substrate 100B.

  On the surface side of the head substrate 100B, the switching valve 32, the nozzle 6B, the charging electrode 7B, the deflection electrode 9B, and the gutter 11B are fixed, and a printing unit 610B is formed. A phase sensor 60B and ink recovery channels 22B and 22 are fixed to the back side of the head substrate 100B and covered with a protective cover 101B. A cable 620 is connected to the head substrate 100B, and the ink supply channel 21, the ink recovery channel 22, and the solvent channel 23 pass through the head substrate 100B. Signal cables (not shown) such as various electrodes and sensors are wired on the back side of the head substrates 100A and 100B. The supply channel 27 is branched into supply channels 27A and 27B on the head substrate 100B.

  The shielding plate 675 is a conductive plate having a ground potential between the printing unit A and the printing unit B, and is fixed to the head substrate 100B or the head cover 615. The shielding plate 675 can prevent electrical interference with the adjacent printing unit, and can prevent the ink ejected by bending from polluting the adjacent printing unit.

  The head substrate 100A is formed with a through hole through which a screw 30 serving as a discharge direction setting device is passed. The head substrate 100B is provided with a female screw into which the screw 30 is fitted. The head substrate 100A is attached to the head substrate 100B by the screw 30. It is fixed. The head substrate 100 </ b> A can be rotated about the central axis by loosening the screw 30. The case where the ejection axes 12A and 12B of the ink particles 8C and 8E that are not used for printing are parallel is set as a reference (rotation angle = 0 °), and in this embodiment, the head substrate 100A is within a rotation angle range of −5 ° to + 5 °. That is, the printing unit 610A can be moved.

  FIG. 9 shows a peripheral structure of a screw 30 that is a discharge direction setting device. The hole 400 is a through hole formed in the head cover 615 so that the screw 30 and the linear positioning mark 450 provided on the head substrate 100A can be seen. An angle scale 410 is provided around the hole 400 of the head cover 615. By aligning the positioning marks 450, the angle adjustment of the print head substrate 100A is assisted. Note that the discharge direction setting device for connecting and fixing the printing units 610A and 610B is not limited to a screw, and any device having a function of locking at a desired angle may be used, and a hinge, a stepping motor, or the like may be used.

  As shown in FIG. 8, the discharge shafts 12A and 12B are shifted by ΔX in the X direction and ΔY in the Y direction. In this embodiment, when the printing units 610A and 610B are at the reference position, ΔX = 20 mm. ΔY = 10 mm. When the rotation angle is 0 °, the ejection shafts 12A and 12B are parallel and the direction of deflection of the ink particles is the same. That is, the discharge shafts 12A and 12B are located on planes parallel to each other.

When the printing unit 610A is rotated from the rotation angle = 0 °, the ejection shafts 12A and 12B are twisted relative to each other. When the rotation is in the positive direction, the printing area 700A approaches the printing area 700B and overlaps depending on the printing conditions. Can do. On the other hand, when rotated in the negative direction, the print area 700A can be separated from the print area 700B. In this embodiment, the printing area can be moved 10 mm at a rotation angle = 5 °.
[Print example of print area]
Next, a printing example of the printing area in the ink jet recording apparatus of this embodiment will be described with reference to FIG. In this embodiment, if the charging voltage is in the range of 90 V (lower limit voltage) to 360 V (upper limit voltage), the distance from the end face of the print head 610 to the object to be printed (printing distance) L = 10 mm. The printing area in the sub-scanning direction Y is about 10 mm wide on the object 500.

  FIG. 10 shows an example in which four lines of character strings are printed on the substrate 500 with L = 15 mm. The printing unit 610A prints two lines of numbers, and the printing unit 610B prints two lines of alphabets. The print areas 700 </ b> A and 700 </ b> B are approximately 10 mm, and four lines of character strings having a character height of 4.5 mm are formed on the substrate 500. The used fonts are all 10 dots (Y direction) × 7 dots (X direction). The rotation angle of the printing unit 610A is 0 °.

  A line 701 is a printing position of the lowest dot of the font on the first line, and in this embodiment, is a printing position when the ink particle 8D has a charging voltage of 90V. A line 702 is a printing position of the uppermost dot of the font on the first line. In this embodiment, the printing position is when the ink particle 8D has a charging voltage of 210V. A line 703 is a printing position of the lowest dot of the font on the second line. In this embodiment, the printing position is when the ink particle 8D has a charging voltage of 240V.

  A line 704 is a printing position of the uppermost dot of the font on the second line. In this embodiment, the printing position is when the ink particle 8D has a charging voltage of 360V. A line 711 is a printing position of the lowest dot of the font on the third line. In this embodiment, the printing position is when the ink particle 8F has a charging voltage of 90V. A line 712 is a printing position of the uppermost dot of the font on the third line. In this embodiment, the printing position is when the ink particle 8F has a charging voltage of 210V.

  A line 713 is a printing position of the lowest dot of the font on the fourth line, and in this embodiment, is a printing position when the ink particle 8F has a charging voltage of 240V. A line 714 is a printing position of the uppermost dot of the font on the fourth line. In this embodiment, the printing position is when the ink particle 8F has a charging voltage of 360V. The area gap 720 may be an interval between the line 704 and the line 711 and may be about one print dot or more. However, the character gap in the normal print area (the interval between the line 702 and the line 703, the interval between the line 712 and the line 713, or ) Is preferable. In this embodiment, the area gap 720 is about 1 mm.

  Since the printing unit 610A can be rotated up to ± 5 ° and the printing area can be moved ± 10 mm, the printing area 700A is moved in the Y direction by rotating the printing unit 610A, and the printing areas 700A and 700B are overlapped. You can also. Further, the area gap 720 can be widened by rotating in the reverse direction.

  FIG. 11 is a print sample (rotation angle = 0 °) of two-line printing by printing the first and third lines under the printing conditions of FIG. 10 (the charging voltage and the distance L are the same). In this case, the print areas 700A and 700B are the same, and the area 720 to the line 711 is an area gap 720A. In this embodiment, the character gap 720A is about 6.5 mm. Also in this printing example, by rotating the print head 610, the area gap can be reduced until the characters in the print areas 700A and 700B are overlapped.

FIG. 12 is a print sample (rotation angle = 0 °) of two-line printing by printing the second and third lines in FIG. In this case, the character gap in FIG. 12 is the same as that in FIG. 10 and is between the lines 704 and 711 and is 1 mm. However, the printing in the printing area 700A in FIG. 12 is inferior in printing quality because the charging voltage is larger than that in the printing area 700A in FIG. This is because, when the charging voltage is high, the charge amount of the ink particles is high, and a large Coulomb repulsion is received during the flight, so that the ink particle adhesion position (dot position) is shifted.

  FIG. 13 is a printing sample of two-line printing by printing the first line and the third line by rotating the printing unit 610A in the forward direction under the printing conditions of FIG. When the printing unit 610A rotates forward, the printing area 700A moves in the sub-scanning direction, and the printing areas 700A and 700B overlap. In this embodiment, the printing unit 610A is rotated so that the line 703 and the line 711 and the line 704 and the line 712 coincide with each other in order to set the character gap 720B to the same 1 mm as in FIG. The rotation angle is about + 3 °. In this case, good printing is possible in an area where the amount of deflection is small and the amount of charge is small.

  In this embodiment, the case where two lines of character strings are printed in one print area has been described. However, the effect of the present invention is not limited by the number of print lines and the print font. In the printing area A and the printing area B, printing with different printing dot diameters and printing with different printing fonts can be set.

  Although an example has been shown above, by moving one of the two printing units relatively in the sub-scanning direction (deflection direction) of the ink particles, the printing position can be changed while maintaining the printing quality. , Character gap can be adjusted arbitrarily.

1: ink container, 2: supply pump, 6A, 6B: nozzle, 7A, 7B: charged electrode, 8A, 8B: ink particles, 11A, 11B: gutter, 14: recovery pump, 15: solvent pump, 16: solvent container , 21: ink supply channel, 22: ink recovery channel, 23: solvent channel, 34: recovery valve, 600: inkjet recording device, 610: print head, 610A, 610B: printing unit

Claims (10)

A print head for printing on a printing object; and a plurality of printing units, each having a nozzle, a charging electrode, a deflection electrode, and a gutter, for discharging ink particles to the printing object; In the continuous discharge type inkjet recording apparatus having a printing area on each of the printing objects,
The print head is provided with a discharge direction setting device for changing at least one ink discharge shaft of the print unit with respect to the discharge shaft of another print head, and a position of a print area on the printing object of the plurality of print units A continuous discharge type ink jet recording apparatus characterized in that is variable.   2. The continuous discharge type inkjet recording apparatus according to claim 1, wherein at least one of the printing units is pivotally supported with respect to the print head.   3. The continuous discharge type ink jet recording apparatus according to claim 1, wherein the discharge direction setting device includes a fixing unit that rotatably supports and fixes the print unit in the print head. Type ink jet recording apparatus.   4. The continuous discharge ink jet recording apparatus according to claim 1, wherein the printing unit has the nozzle, the charging electrode, the deflection electrode, and the gutter mounted on a head substrate, and at least one of the printing units is A continuous discharge type ink jet recording apparatus which is rotatably supported on a head substrate of another printing unit.   5. The continuous discharge type ink jet recording apparatus according to claim 2, further comprising an angle adjusting means for adjusting an ink discharge angle of at least one of the printing units. .   6. The continuous discharge type ink jet recording apparatus according to claim 1, wherein the ink discharge shafts of at least two printing units are included in a plane parallel to each other and are in a twisted positional relationship. An ink jet recording apparatus.   7. The continuous discharge type ink jet recording apparatus according to claim 1, further comprising a branch path that distributes ink supplied from a supply pump to at least two of the print units, and the branch path includes two of the branch paths. An ink jet recording apparatus, wherein the ink jet recording apparatus is disposed on one of the head substrates of the printing unit.   8. The continuous discharge type ink jet recording apparatus according to claim 7, wherein an opening / closing valve is provided on at least one of the branch paths.   9. The continuous discharge ink jet recording apparatus according to claim 1, wherein a shielding member having a ground potential is provided between at least two of the printing units.   10. The continuous discharge ink jet recording apparatus according to claim 1, wherein each printing unit includes at least two printing units and a detection sensor that detects a printed matter corresponding to the printing units. An ink jet recording apparatus.

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