JP3161486B2 - Ink jet print head and ink jet printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet print head and an ink-jet printer which discharge ink and a transparent solvent to perform gradation printing on a printing material.

[0002]

2. Description of the Related Art Ink and a transparent solvent (including a white solvent.
Lower, by ejecting the same) Herein, the ink-jet printhead which performs printing with a gradation on the substrate such as a printed paper is conventionally discharged after mixing the ink and the transparent solvent in the head I was

[0003]

However, according to the conventional ink jet print head configured as described above, the ink and the transparent solvent are mixed at an unnecessary time such as during standby, and a long-term chemical And a physical reaction was likely to occur, and the properties of both solutions were liable to change. As a result, there is a problem that the density control becomes unstable during printing and the quality of the printed image becomes unstable. If a valve is provided in the supply path of each liquid in order to prevent the mixing of the two liquids, the structure becomes complicated.

The present invention has been made in view of such a situation, and an ink jet print head and an ink jet printer which can prevent unnecessary mixing of ink and a transparent solvent and can perform good gradation expression. The purpose is to provide.

[0005]

Means for Solving the Problems] The printhead of claim 1, an ink discharge hole for discharging ink, and the transparent solvent ejection hole for ejecting the transparent solvent, ink
Controls the size of ink droplets ejected from the pop-up holes
Is discharged by the first control means and the transparent solvent
And a second control means for controlling the size of droplets of the transparent solvent, both discharge holes, a droplet of ink and the transparent solvent discharged from each of the two discharge holes, after the ejection, which can be combined in the air A first control means and a second control
Means so that the droplet diameter after coalescence in air is almost constant
In addition, the size of the droplet of the ink and the transparent solvent is controlled .

[0006] The discharge hole includes one transparent solvent discharge hole,
A plurality of ink jets, each jetting a different color ink
And a vent hole.

[0007] The discharge hole includes one transparent solvent discharge hole,
A plurality of ink jets, each jetting a different color ink
A plurality of groups of discharge holes including outlets are arranged in parallel.
Can be achieved.

[0008] The ink and the transparent solvent are applied to an electrostrictive element.
Discharge drive.

An ink jet printer according to claim 5.
Is an ink jet print head according to claim 1.
It is characterized by having.

[0010] The direction of the axis of the drum that rotates by rotating the substrate
The inkjet print head is arranged so that it can be
And print the inkjet printhead on the drum.
A drive member that moves in conjunction with the rotation of
You can make it.

[0011] The direction of the axis of the drum that rotates by rotating the substrate.
The inkjet print head is arranged so that it can be
And allow the drum to
Drive that rotates in conjunction with the movement of the jet print head
A moving member may be further provided.

[0012] A drum for winding around the substrate to be printed and rotating
In the axial direction, several inkjet print heads
It can be arranged in an in shape.

[0013]

[0014]

The ink jet print head according to claim 1 is provided.
And the inkjet printer according to claim 5.
In other words, the ink is ejected, the transparent solvent is ejected,
The droplets of the ink and the transparent solvent are combined in the air after ejection.
And controlled so that the droplet diameter after coalescence becomes almost constant.
It is.

[0015]

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the ink jet print head and the ink jet printer of the present invention will be described below with reference to the drawings.

FIGS. 13 to 16 show examples of the configuration of an ink jet printer equipped with the ink jet print head 31 according to the present embodiment. FIG. 13 shows a configuration example of a drum rotation type. A printing paper 32 as a printing material is wound around the outer circumference of a drum 33 and fixed at a predetermined position. A feed screw 34 is provided on the outer periphery of the drum 33 in parallel to the drum axis direction, and the head 31 is screwed to the feed screw 34. The rotation of the feed screw 34 causes the head 31 to move in the axial direction. The drum 33 is driven to rotate by a motor 38 via a pulley 35, a belt 36, and a pulley 37. Further, the drive of the rotation of the feed screw 34 and the motor 38 and the drive of the head 31 are controlled by the drive control unit 39 based on the print data and the control signal 40.

In the above configuration, when the drum 33 rotates, ink is ejected from the head 31 in synchronization with the rotation,
An image is formed on the print paper 32. One drum 33
When the printing is completed and one line is printed on the printing paper 32 in the circumferential direction, the feed screw 34 is rotated to move the head 31 by one pitch, and the next line is printed. In this case, there is a method of simultaneously rotating the drum 33 and the feed screw 34 and gradually moving the head 31 while printing. In the case of a multi-nozzle head or a configuration in which the same location is printed several times, step feed is suitable. However, if the number of single nozzles or multi-nozzles is small, the drum 33 and the feed screw 3
While simultaneously rotating the prints 4 and 4, the printing in a spiral shape is performed.

FIG. 14 shows an example of a serial type configuration. In this case as well, the configuration is substantially the same as that of the drum rotary type shown in FIG. 13, except that the print paper 32 is not wound around the drum 33, and the paper press roller 41 provided in parallel to the axial direction is used for the drum. 33. in this case,
When the head 31 moves and prints one line, the drum 3
1 is rotated by one line, and the next line is printed. The head 31 may move in the same direction or in the reciprocating direction.

FIG. 15 shows a line type configuration example. In this case, instead of the serial type head 31 and the feed screw 34 shown in FIG. 14, a line head 42 in which a number of heads 31 are arranged in a line is fixedly provided in the axial direction. In this configuration, printing of one line is performed simultaneously by the line head 42, and when printing is completed, the drum 33 is rotated by one line to print the next line. In this case, all lines can be printed at once, divided into multiple blocks,
A method of alternately printing every other line is also conceivable.

FIG. 16 is a block diagram of a printing and control system. The signal 51 such as print data is sent to the signal processing / control circuit 5
2 and are sent to a head 54 via a driver 53 after being arranged in a printing order in a circuit 52. The order of printing differs depending on the configuration of the head and the printing unit, and also has a relationship with the order of inputting print data. The head 54 outputs a gradation signal and an ejection signal.

When the number of nozzles is very large in a multi-head, an IC is mounted on the head 54 to reduce the number of wires connected to the head 54. Further, a correction circuit 56 is connected to the signal processing / control circuit 52, and performs γ correction, color correction in the case of color, and variation correction of each head. Generally, predetermined correction data is stored in the correction circuit 56 in the form of a ROM map, and is taken out according to external conditions such as a nozzle number, a temperature, and an input signal.

The signal processing / control circuit 52 includes a CPU and a DSP.
Generally, the processing is performed by software, and the processed signal is sent to various control units 57. The various control units 57 control the driving of the motor for rotating the drum 33 and the feed screw 34, the synchronization, the cleaning of the head, the supply and discharge of the print paper 32, and the like. Needless to say, the signal 51 includes an operation unit signal and an external control signal other than the print data.

FIGS. 1 and 2 show the structure of an ink jet print head according to the present invention. 1 and 2, an ink chamber 2 and a transparent solvent chamber 3 are formed in a head 1.
An ink 6 and a transparent solvent 7 are supplied from an ink supply port 4 and a transparent solvent supply port 5 provided at one end, respectively. The other ends of the ink chamber 2 and the transparent solvent chamber 3 are provided with orifices 8 and 9 as an ink ejection hole and a transparent solvent ejection hole, respectively. Further, flat electrostrictive elements 10 and 11 are provided on the side walls of the ink chamber 2 and the transparent solvent chamber 3, and voltage generating parts 12 and 13 are connected to both poles of the electrostrictive elements 10 and 11, respectively. . The voltage generators 12 and 13 are driven by external electric signals, and the amplitudes of the electrostrictive elements 10 and 11 are controlled.

Next, the operation of this embodiment will be described with reference to FIGS. The ink 6 and the transparent solvent 7 introduced into the ink chamber 2 and the transparent solvent chamber 3 through the ink supply port 4 and the transparent solvent supply port 5, respectively, are used to drive the electrostrictive element 10 driven by an electric signal corresponding to a desired concentration. , 11 are discharged from the orifices 8, 9 respectively. The ejected droplets 6a and 7a of the ink 6 and the transparent solvent 7 are united in the air as shown in FIG. 1 to form a mixture 14 having a predetermined concentration, and are absorbed by a printing paper 15 as a member to be printed. You.

At this time, it is necessary to set the positions of the orifices 8 and 9 and the ejection timing so that the droplets 6a and 7a can be combined in the air. That is, as shown in FIG. 3, the ink 6 and the transparent solvent 7 are discharged in synchronization with the reference clock T. At this time, when lowering the concentration of the mixed liquid 14, the droplet 7a of the transparent solvent 7 is large and the droplet 6a of the ink 6 is large.
The amplitude W of the displacement of the electrostrictive elements 11 and 10 provided in the respective liquid chambers 3 and 2 is controlled by an electric signal so that a becomes smaller. Conversely, when increasing the density, the amplitude W of the electrostrictive elements 11 and 10 is controlled by an electric signal so that the droplet 7a of the transparent solvent 7 is small and the droplet 6a of the ink 6 is large. In each case, the respective electric signals are controlled so that the droplet diameters of the mixed liquid 14 after the combination become substantially the same.

In the above embodiment, the case where the droplet 6a of the ink 6 and the droplet 7a of the transparent solvent 7 are combined and mixed in the air, but the mixing position is not limited to the air.
As shown in FIG. 4, it may be on print paper 15. This can be realized by adjusting the positions of the orifices 8 and 9, that is, the intervals and angles. In this case, since the droplets 6a and 7a do not need to unite in the air, the ejection timings of the two liquids 6 and 7 may be shifted as shown in FIG. 5A or 5B. That is, there is a margin in the ejection timing, and the margin is determined by the relative time relationship between the ink 6 and the transparent solvent 7. For example, when the ink 6 is used as a reference, the ejection timing of the transparent solvent 7 can be shifted from the reference clock Ta by ± 30% of one cycle of the reference clock T.

According to this embodiment, the ink 6 and the transparent solvent 7
Are discharged from separate orifices 8 and 9, respectively, and the two liquids 6 and 7 are mixed after the discharge. Therefore, natural mixing of the two liquids 6 and 7 can be prevented. By controlling the size of the droplets 6a, 7a of the seventh so as to change according to the gradation, correct gradation expression can be performed. Moreover, the structure of the head is simplified since no mixing section is required.

In the above embodiment, a single-color ink jet print head has been described. However, similar effects can be obtained by applying the present invention to a multi-color ink jet print head.
In this case, as shown in FIG. 6, an orifice 9 as one transparent solvent ejection hole, yellow, magenta, cyan,
Orifices 8Y, 8M, 8C, and 8K as ink ejection ports for ejecting four black inks 6 may be arranged on the line. Then, ink droplets 6a of each color having a size corresponding to a desired density are ejected together with a transparent solvent 7 necessary for each density. Thus, full-color multicolor printing can be performed.

In order to increase the printing speed, FIG.
As shown in FIG. 6, a plurality of orifice rows shown in FIG.

In each of the above embodiments, the case where the droplet amount is changed in an analog manner in order to obtain the density gradation of the ink 6 has been described. For example, as shown in FIG. One orifice 9 and four orifices 8 as ink ejection holes may be provided, and the opening and closing of the four orifices 8 may be controlled by digital signals. That is, the density gradation of the ink 6 can be obtained by the number of the opened orifices 8. In this case, the number of orifices 8 is 2 n
By using the power, the opening / closing drive of the orifice 8 can be directly performed by a digital signal.

In order to increase the printing speed, FIG.
As shown in FIG. 8, a plurality of orifice groups shown in FIG. Further, the amount of ink droplets may be controlled by using both the analog method and the digital method.

In each of the above embodiments, the case where the flat type electrostrictive elements are used as the electrostrictive elements 10 and 11 has been described.
A cylindrical electrostrictive element 21 shown in FIG. 10 may be used. As shown in FIG. 11, a pressure chamber 22 and an ink supply path 23 communicating with the orifice 8 may be provided, and the ink 6 in the pressure chamber 22 may be pressed by the flat type electrostrictive element 10. This method is called a stem type head. Further, as shown in FIG. 12, a heating-vaporization type having a heating element 24 may be used as the ink discharging means. In this method, as shown in (a), a nuclear bubble 25 is generated on the heating element 24 by heating, the nuclear bubble 25 is grown into a bubble 26 as shown in (b), and the heat is generated as shown in (c). When the heating by the element 24 is stopped and the bubble 26 is contracted,
The ink particles 6a are discharged from the nozzle 8 to the outside as shown in FIG.

[0034]

As described above, according to the ink jet print head and the ink jet printer of the present invention, the ink and the transparent solvent are discharged from the respective discharge holes, and after the discharge, the ink and the transparent solvent are discharged. Droplet
Are combined in the air after ejection, and the droplet diameter after the
Since the control is performed so as to be constant, natural mixing of the two liquids can be prevented, and correct gradation expression can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory side view showing a configuration of an embodiment of an ink jet print head of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a timing chart for explaining the operation of the embodiment of FIG. 1;

FIG. 4 is an explanatory side view showing a configuration of another embodiment of the present invention.

FIG. 5 is a timing chart for explaining the operation of the embodiment in FIG. 4;

FIG. 6 is a front view showing an example of the arrangement of orifices when the inkjet print head of the present invention is multicolored.

FIG. 7 is a front view showing another example of the arrangement of the orifices in FIG. 6;

FIG. 8 is a front view showing an example of the arrangement of orifices in a digital control system of the inkjet print head of the present invention.

FIG. 9 is a front view showing another example of the arrangement of the orifices in FIG. 8;

FIG. 10 is an explanatory diagram showing another configuration of the electrostrictive element shown in FIG.

FIG. 11 is an explanatory diagram showing another configuration of the head shown in FIG. 1;

FIG. 12 is an explanatory diagram showing another configuration of the head shown in FIG. 1;

FIG. 13 is an explanatory diagram illustrating a configuration of an example of a drum rotation type ink jet printer to which the head of the embodiment is applied.

FIG. 14 is an explanatory diagram illustrating a configuration of an example of a serial type inkjet printer to which the head of the present embodiment is applied.

FIG. 15 is an explanatory diagram illustrating a configuration of an example of a line-type inkjet printer to which the head of the embodiment is applied.

FIG. 16 is a block diagram illustrating a configuration of an example of a signal processing and control system of the inkjet printer.

[Explanation of symbols]

 1, 31 Head 6 Ink 7 Transparent solvent 6a, 7a Droplet 8 Orifice (ink ejection hole) 9 Orifice (transparent solvent ejection hole) 10, 11, 21 Electrostrictive element 15, 32 Print paper (substrate to be printed) 33 Drum 34 Send Screw (drive member)

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Claims (8)

(57) [Claims] An ink ejection hole for ejecting ink, a transparent solvent ejection hole for ejecting a transparent solvent, and a size of an ink droplet ejected by the ink ejection hole.
First control means for controlling the size of the transparent solvent droplets discharged by the transparent solvent exit hole
A second control unit for controlling the size , wherein the two ejection holes are arranged at positions where the ink and transparent solvent droplets respectively ejected from the two ejection holes can be combined in the air after ejection. It is, the first control means, and said second control means,
In order to make the droplet diameter after coalescence in the air almost constant,
An ink- jet printhead, wherein the size of droplets of the ink and the transparent solvent is controlled . Wherein said discharge holes, before the plurality of ejecting and one of the transparent solvent ejection holes, the different color inks, respectively
2. The ink jet recording apparatus according to claim 1 , further comprising an ink discharge hole.
On-board inkjet printhead . Wherein the discharge hole is before a plurality of discharge and one of the transparent solvent ejection holes, the different color inks, respectively
2. An ink jet apparatus according to claim 1 , wherein a plurality of groups of the ejection holes including the ink ejection holes are arranged in parallel.
Jet print head . 4. The ink jet print head according to claim 1, wherein the ink and the transparent solvent are ejected and driven by an electrostrictive element. 5. The ink jet print according to claim 1,
Ink-jet printing characterized by comprising a head
Ta. 6. A drive for arranging the ink jet print head so as to be movable in the axial direction of a drum that rotates while rotating a printing medium, and that moves the ink jet print head in conjunction with the rotation of the drum. a member
Ink jet printer according to claim 5, characterized in that provided in et. 7. A drum shaft for winding around a substrate to be printed and rotating.
The ink jet print head is disposed so as to be movable in the
6. The ink jet printer according to claim 5 , further comprising a driving member that rotates in conjunction with the movement of the jet print head. 8. The ink- jet printer according to claim 5 , wherein a plurality of said ink-jet print heads are arranged in a line in the axial direction of a drum on which a printing material is wound and rotated.