JPS627496Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink-on-demand type inkjet printer, and particularly to a compact printer.

Since the ink-on-demand type inkjet printer uses extremely low printing energy, it can be considered to be applied to a small portable printer using a battery as a driving source. For example, FIG. 1 shows an example of use in a portable calculator. 1 is a printer, 2 is a recording paper that is fan-hold paper, 3 is a paper feeding member, 4 is a control circuit, 5
6 is a battery, 6 is an input switch, 7 is a case, and 9 is a display using a liquid crystal or the like.

As can be seen from the layout shown in Figure 1, when trying to put together a thin calculator, it is preferable not to overlap the display 9 and printer 1, and as a calculator, the top 8 of the case 7 becomes a dead space, which is uninteresting in terms of design. . Also, the total length of the calculator becomes longer. Therefore, it is desirable that the depth D of the printer 1 is as short as possible.

The present invention aims to shorten the depth D of the printer 1 and to suppress the deterioration of printing performance.

FIG. 2 shows an embodiment of the present invention. Reference numeral 11 denotes a print head, in which four nozzles 12 are arranged in this example. 13 is a piezoelectric element, 14 is an ink tank,
15 is a guide shaft that guides the print head 11 and the ink tank 14 so that they can reciprocate in the direction of the arrow; 16 is a cam that engages with the pin 17 to reciprocate the print head 11 and the ink tank 14; 18 is a reduction gear; 1
9 is a motor, 20 is a tachometer generator that generates a print timing signal, and 21 is a frame. Although not shown, the paper feed member 3 shown in FIG. 1 is arranged below the print head 11. Although not shown, a lid for preventing nozzle clogging is provided on the print head 11. The operation will be explained in the above embodiment. The rotation of the motor 19 causes the cam 16 to rotate and the print head 11 to reciprocate as shown by the arrow. In response to a print timing signal from the tachogenerator 20, a signal from the control circuit 4 (FIG. 1) is applied to the piezoelectric element 13 via a conductive member (not shown), and ink is ejected from the nozzle 12 to print on the recording paper 2. (FIG. 1) a dot is printed. In synchronization with the reciprocating movement of the print head 11, the paper feed member 3 (FIG. 1) is operated by a transmission mechanism (not shown), and the recording paper 2 is fed as shown by arrow A in FIG. Therefore, the relative movement between the recording paper 2 and the printing head 11 is as shown by arrow B, and printing is performed while scanning the printing range of the recording. Print head 1 as shown in the embodiment of FIG.
By making the ink tank 14 multi-nozzle and reciprocating it at the same time as the ink tank 14, energy loss due to bending of the tube, such as when a plastic tube is used to connect the ink tank 14 and the print head 11, and the ink leaking through the tube can be avoided. There are no problems such as air entering the printer and making it impossible to print. In addition, by using a so-called shuttle type in which the multi-nozzles are arranged in the reciprocating direction, the required stroke is shortened and waste space is reduced, so even if the depth D of the printer 1 is shortened, the ink tank 14
capacity can be increased.

FIG. 4 shows an enlarged view of the main parts of the print head 11 of the embodiment shown in FIG. The print head 11 is a planar print head in which a diaphragm on which a piezoelectric element is bonded is superimposed on a substrate in which a flow path is formed as a recess.

Ink 30 from ink tank 14 (Figure 2)
The air passes through the coupling member 31, passes through the air trap 32 that prevents air bubbles and dirt from passing through, and enters the pressure chamber 35 through the flow path 33 and the supply path 34. As is clear from the drawings, the pressure chamber 35 has a rectangular shape with its long sides extending in the direction of the reciprocating movement of the print head.
A piezoelectric element 13 is arranged on the outer surface of the pressure chamber 35,
Due to this deformation, the ink 30 is ejected from the nozzle 12 as an ink droplet 36 and is recorded on the recording paper 2.

As mentioned above, it is better for the depth D of the printer 1 to be as short as possible, so it is desirable to make the depth d of the print head 11 as small as possible. In the present invention, the length of side a of the piezoelectric element is shortened, and the reduction in injection capacity due to the accompanying reduction in capacity of the piezoelectric element, increase in the rigidity of the vibration system, and reduction in pressurizing chamber volume is avoided by lengthening side b. I'm holding it down. Further, the supply path 34 and the nozzle 12 are arranged diagonally of the pressurizing chamber 35, and the pressurizing chamber 3 on the other diagonal
By creating a radius 37 at the corner of 5, the ink flows smoothly. This increases the ejection capacity, and even if bubbles occur in the pressurized chamber and printing becomes impossible, they can be easily removed from the nozzle along with the ink by pressing the ink tank 14 or the like. Also, when ink is first poured into the print head, no air bubbles remain in the pressurizing chamber, making work easier.

The print head 11 can be integrally formed into a multi-nozzle by injection molding of plastic or the like. Furthermore, in the embodiment shown in FIG. 2, the piezoelectric element 13 is individually arranged for each pressurizing chamber, but one piezoelectric element is arranged for a plurality of pressurizing chambers, and only the electrodes are placed in each pressurizing chamber. It is also possible to eject ink independently. This method is advantageous in terms of cost. in this way,
Since the inkjet printer of the present invention is a shuttle type in which a plurality of nozzles are arranged in the direction of the reciprocating movement of the print head, high-speed printing can be achieved. At this time, while multiple pressure chambers are mounted on the print head, the shape of the pressure chamber is such that the long side is in the direction of the reciprocating movement of the head, so the side of the adjacent pressure chamber is the short side, and it is a shuttle type. It is possible to eliminate interference between pressure chambers, which is a problem when using a print head, and to mount the nozzles on the print head with high density, making it possible to perform stable printing while enabling high-speed printing. The pressure chamber has a rectangular shape with its long side in the direction of the reciprocating movement of the print head, so that a sufficient area can be ensured and sufficient pressure can be applied for ink ejection. Further, since the ink in the pressure chamber has a nozzle for ejecting ink in a diagonal direction of the pressure chamber and an ink supply port into the pressure chamber, pressure does not escape when pressure is applied, and pressure is applied efficiently. Because the other diagonal corner of the square pressure chamber is rounded, air bubbles remain inside the pressure chamber despite the long distance from the ink supply port to the nozzle, making printing impossible due to pressure absorption by the air bubbles. It does not cause Further, by making the pressure chamber square in shape, the ratio of the area of the pressure chamber to the entire area of the printing head can be increased, and the head can be made smaller.

Although the present invention is particularly effective for battery-powered portable printers, it can also be applied to various other inkjet printers, plotters, facsimile machines, etc., and the scope of the claims is not limited thereto.

[Brief explanation of the drawing]

1 is a sectional view of a calculator using the inkjet printer of the present invention, FIG. 2 is a plan view of an embodiment of the inkjet printer of the present invention, and FIG.
FIG. 4 is a plan view of the main part of the print head of the embodiment shown in FIG. 2. FIG. 1... Printer, 2... Recording paper, 11... Print head, 12... Nozzle, 13... Piezoelectric element, 1
4... Ink tank, 34... Supply path, 35...
Pressurized chamber.

Claims (1)

[Scope of utility model registration request] In a shuttle type inkjet printer in which a plurality of nozzles are arranged on a print head in the direction of reciprocating movement of the print head, a pressure chamber is provided on the print head corresponding to each nozzle, and a piezoelectric voltage is provided on the print head corresponding to the pressure chamber. The element is arranged, and the shape of the pressure chamber is such that one diagonal corner has a corner, the other diagonal has the nozzle and an ink supply port to the pressure chamber, and the pressure chamber has a shape in which the nozzle and the ink supply port to the pressure chamber are provided in the other diagonal direction. An inkjet printer characterized in that the inkjet printer has a rectangular shape with long sides and ejects the ink in a direction intersecting the long side direction substantially on an extension plane of the pressure chamber.