JPH11268265A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording apparatus which can prevent crosstalk between nozzles from being generated by changing structure of a diaphragm. SOLUTION: In an ink-jet recording apparatus, as a projection 120 whose vertical face 121 is faced to a common ink room 125 and inclined face 122 is faced to a pressure generating room 123 is formed on a diaphragm 116 of a recording head 16, when the diaphragm 116 is deformed so as to contract the pressure generating room 123, the vertical face 121 of the projection 120 acts so as to shear ink in a common ink room 115. Therefore, as a large pressure is not transmitted to the common ink room 125, in this case, there exists no possibility that ink droplets are not injected from another nozzle 111 from which the ink droplets should not be injected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording apparatus such as an ink jet printer. More specifically, the present invention relates to a structure of a diaphragm for contracting a pressure generating chamber in a recording head.

[0002]

2. Description of the Related Art An ink jet recording apparatus having a recording head for ejecting ink droplets from nozzle openings in accordance with recording contents has been conventionally used in printers and facsimile machines. In this ink jet recording apparatus, a plurality of nozzles 111 are formed in the recording head 16 as shown in FIG. 3, and in each of these nozzles 111, as shown in FIG. A pressure generating chamber 113 communicating with the opening, and the pressure generating chamber 11
A pressure generating element such as a piezoelectric vibrator PZT that discharges ink droplets from the opening of the nozzle 111 by contracting the pressure generating chamber 113 by deforming the vibration plate 116 that forms one wall surface of the nozzle 3. Also, a plurality of pressure generating chambers 113
And a common ink chamber 115 for supplying ink when each pressure generating chamber 113 expands. Diaphragm 11
6 has a thin portion 125 for facilitating deformation, but is constituted by a flat thin plate as a whole.

With such a configuration, the piezoelectric vibrator PZT contracts from the state shown in FIG. 6A, and the diaphragm 116 flexes upward as shown in FIG.
When the ink 13 expands, the ink in the common ink chamber 115 flows into the pressure generating chamber 113 via the ink supply port 114 as shown by an arrow R. After a lapse of a predetermined time, the piezoelectric vibrator PZT expands, and as shown in FIG.
When the pressure generating chamber 113 contracts due to the return of the pressure 16, the ink in the pressure generating chamber 113 is compressed and the ink droplet is ejected from the opening of the nozzle 111 as shown by the arrow D. At this time, the large number of nozzles 11 formed in the recording head 16
1, a predetermined character or the like is recorded depending on which of the ink droplets is ejected.

[0004]

However, in the conventional recording head 16, since the inner surface of the diaphragm 116 is flat, the pressure when the pressure generating chamber 113 contracts is indicated by an arrow P.
As shown by the arrow, it acts toward the pressure generating chamber 113 (toward the opening of the nozzle 111), and as shown by the arrow Q,
It also joins the common ink chamber 115. As a result, the pressure is also applied to the other pressure generating chambers 113 which normally do not discharge the ink droplets this time through the common ink chamber 115, and the ink droplets are slightly transmitted from the openings of the other nozzles 111. Is discharged. The problem of such crosstalk is that when printing on an uneven surface using an ink jet recording apparatus, or when the recording head 16 and the printing surface are separated from each other, it is necessary to fly the ink droplets straight up to a distance. This is remarkable when the ejection pressure of the ink droplet is increased.

Accordingly, an object of the present invention is to provide an ink jet recording apparatus capable of preventing the occurrence of crosstalk between nozzles by changing only the structure of the diaphragm without changing the basic structure. It is in.

[0006]

According to the present invention, a pressure generating chamber communicating with a nozzle opening and a diaphragm constituting one wall of the pressure generating chamber are deformed. Each of the pressure generating chambers has a plurality of pressure generating elements for contracting the pressure generating chambers to eject ink droplets from the nozzle openings, and has a common ink chamber communicating with the plurality of pressure generating chambers and supplying ink when the pressure generating chambers expand. In the ink jet recording apparatus, the vibration plate has a projection which directs a vertical surface toward the common ink chamber and a slant surface toward the pressure generation chamber in a communication portion between the pressure generation chamber and the common ink chamber. It is characterized by being formed.

According to the present invention, the vibration plate has a vertical surface facing the common ink chamber, and a pressure generating chamber (nozzle opening).
Is formed, the vertical surface of the projection acts to shear the ink in the common ink chamber when the diaphragm is deformed so as to contract the pressure generating chamber. Therefore, even when the diaphragm is deformed so as to contract the pressure generating chamber, since a large pressure is not transmitted to the common ink chamber, ink droplets are discharged from other nozzles which should not discharge ink droplets this time. No problem (crosstalk) occurs. In addition, it is possible to increase the ejection pressure of ink droplets without considering the problem of crosstalk. Also, in the pressure generating chamber, the slope of the projection acts to push the ink into the pressure generating chamber, so that the pressure due to the contraction of the pressure generating chamber (deformation of the vibration plate) is efficiently transmitted to the nozzle opening. . Therefore, since the ejection pressure of the ink droplet can be increased, there is also an advantage that the ink droplet can fly straight to a long distance.

[0008] In the present invention, it is preferable that the slope of the projection forms an angle of about 45 ° with the diaphragm. With this configuration, the slope of the projection acts to push the ink into the pressure generating chamber with a large force, so that the pressure due to the contraction of the pressure generating chamber (deformation of the vibration plate) is more efficiently directed toward the nozzle opening. The transmitted pressure of the ink droplet can be maximized.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet recording apparatus to which the present invention is applied will be described with reference to the drawings. Here, it goes without saying that the ink jet recording apparatus can be configured to perform recording on recording paper, but the ink jet recording apparatus has many advantages such as being able to perform printing or the like on a medium in a non-contact manner. Here, as an ink jet recording apparatus that performs recording on a medium other than recording paper, an apparatus configured for marking on an IC will be described as an example. In addition,
In the ink jet recording apparatus described below, the basic configuration of the recording head is common to that of the conventional one, and therefore, the corresponding parts are denoted by the same reference numerals.

(Overall Configuration) FIG. 1 is an external view of an ink jet recording apparatus to which the present invention is applied, and FIG. 2 is a perspective view showing the configuration inside the recording apparatus main body.

As shown in FIG. 1, an ink jet recording apparatus 1 of the present embodiment has a plurality of I / Os arranged on a tray TR.
It is for marking an inspection number or the like on each package upper surface 20 of C2, and has a recording apparatus main body 10 and a tray transport table 3 for transporting the tray TR in the direction shown by the arrow A.

As shown in FIG. 2, inside the recording apparatus main body 10 of the ink jet recording apparatus 1, a carriage 11 is connected to a pulse motor 13 via a timing belt 12, and is guided by a guide member 14 so that the width of the tray TR is increased. It is configured to reciprocate in the direction. An ink jet recording head 16 is attached to the surface of the carriage 11 facing the tray TR, in the example shown in FIG. The recording head 16 receives supply of ink from the ink cartridge 17 mounted on the upper part of the carriage 11, and in accordance with the movement of the carriage 11, ink drops on the package upper surface 20 of each IC 2 disposed on the tray TR. Is ejected to form dots, and an inspection number or the like is printed on the package upper surface 20 of each IC 2. In the non-printing area of the ink jet recording apparatus 1, a capping device 18 is provided to seal the nozzle openings of the recording head 16 during the pause of recording, and discharge the recording head 16 during the flushing operation performed during the printing operation. Received ink drops.
A cleaning device 19 is provided near the capping device 18.
The cleaning device 19 is configured to wipe off the ink residue adhering thereto by wiping the surface of the recording head 16 with a blade or the like.

The ink used is prepared by dissolving or dispersing a dye or pigment, a surfactant such as ethylene glycol or the like in a solvent such as water, alcohol, toluene or methyl ethyl ketone. Further, if a heater or the like is attached to the recording head, hot melt ink can be used.

(Configuration of Recording Head 16) FIG. 3 is a sectional view showing the configuration of the recording head 16. As shown in FIG.

As shown in FIG. 3, the recording head 16 includes
Although a plurality of nozzles 111 are formed, in each of these nozzles 111, the pressure generating chamber 113 communicating with the opening of the nozzle 111 and the diaphragm 116 forming one wall of the pressure generating chamber 113 are deformed. The pressure generating chamber 113 is contracted by the
A pressure generating element such as a piezoelectric vibrator PZT for discharging ink droplets from the openings of the pressure generating chambers is formed.
A common ink chamber 115 is formed to communicate with the pressure generating chamber 13 and to send ink when each pressure generating chamber 113 expands.

That is, as shown in FIG. 4A, an opening of the nozzle 111 is formed in the nozzle plate 110,
In the flow path forming plate 112, a through hole that partitions the pressure generating chamber 113, a through hole or groove that partitions the ink supply port 114 that communicates with the pressure generating chamber 113, and these ink supply ports 1.
14 are formed to define common ink chambers 115 communicating with each other. Therefore, any pressure generating chamber 1
13 also communicates via a common ink chamber 113. Here, the vibration plate 116 is made of an elastically deformable thin plate, and is in contact with the tip of a piezoelectric vibrator PZT (pressure generating element) such as a piezo element. The vibration plate 16 is fixed integrally with the nozzle plate 110 in a liquid-tight manner with the flow path forming plate 112 interposed therebetween, and forms a flow path unit 118. The diaphragm 116 has a thin portion 1 for facilitating its deformation.
25 are formed.

With such a configuration, the piezoelectric vibrator PZT contracts from the state shown in FIG. 4A, and the diaphragm 116 flexes upward as shown in FIG.
When the ink 13 expands, the ink in the common ink chamber 115 flows into the pressure generating chamber 113 via the ink supply port 114 as shown by an arrow R. After a lapse of a predetermined time, FIG.
From the state shown in (B), the piezoelectric vibrator PZT expands,
As shown in FIG. 4A, when the vibration plate 116 returns to its original state and the pressure generating chamber 113 contracts, the ink in the pressure generating chamber 113 is compressed, and the ink from the opening of the nozzle 111 is Drops are ejected. At this time, the recording head 1
A predetermined character or the like is recorded depending on which of the many nozzles 111 formed in No. 6 ejects an ink droplet.

In the recording head 16 configured as described above, in this embodiment, the inner surface of the diaphragm 116 has a side communicating with the common ink chamber 115, that is, the ink supply port 114.
In the vicinity, the vertical surface 121 faces the common ink chamber 115, and the pressure generating chamber 113 (the opening of the nozzle 111).
Is formed with a projection 120 that faces the slope 122. The slope of the projection 120 makes an angle of about 45 ° with the diaphragm 116.

For this reason, in the recording head 16 of the present embodiment,
When the state shown in FIG. 4B is changed to the state shown in FIG. 4A, that is, when the diaphragm 116 returns to the original shape so as to contract the pressure generating chamber 113, the common ink chamber 115 On the other hand, the vertical surface 121 of the projection 120 acts to shear the ink. Therefore, even when the vibration plate 116 is deformed so as to contract the pressure generating chamber 113, a large pressure is not transmitted to the common ink chamber 115.
In this case, there is no crosstalk in which ink droplets are ejected from other nozzles 111 which should not eject ink.

On the other hand, in the pressure generating chamber 113, the protrusion 12
As shown by an arrow P, the inclined surface 122 acts to push the ink into the pressure generating chamber 113.
Since the inclined surface 122 at 20 forms an angle of about 45 ° with the diaphragm 116, the pressure due to the contraction of the pressure generating chamber 113 (return of the shape of the diaphragm 116) is efficiently transmitted to the opening of the nozzle 111. Is done. Therefore, ink droplets can be ejected from the opening of the nozzle 111 at a high ejection pressure. Therefore I
When marking or the like is performed on the package of C2 by the inkjet recording apparatus 1, the IC2 is considered in consideration of the variation in the height position of the package upper surface 20 of the IC2 on the tray TR.
Even if the recording head 16 is arranged at a position slightly away from the package upper surface 20 of the IC 2 on the tray TR so that the recording head 16 does not come into contact with the recording head 16, if the recording head 16 of the present embodiment is used, the ejection pressure of the ink droplets Since the ink droplets are high, the ink droplets can fly straight to the package upper surface 20 located at a position distant from the nozzle 111.

(Control System of Inkjet Recording Apparatus) FIG.
The configuration of a control system included in the inkjet recording apparatus will be described with reference to FIG.

In FIG. 5, the ink jet recording apparatus 1
The control device 60 is configured to receive a print command signal and print data from the host and receive a print voltage signal from the print head drive circuit 3 and a head selection circuit 32.
0, and also controls the carriage drive circuit 33 and the like to execute the printing operation. The control device 60
Causes the flushing operation or the cleaning operation of the recording head 16 to be performed based on the time measurement data of the timer means 34.

In the recording head driving circuit 30, the driving voltage generating circuit 31 is configured to generate a trapezoidal wave having a voltage value necessary for discharging an ink droplet from the opening of the nozzle 111. Further, the head selection circuit 32 controls the transistor T configured for each nozzle 111 to drive the driving voltage generation circuit 31 to the piezoelectric vibrator PZT corresponding to the print data among the plurality of piezoelectric vibrators PZT. A voltage is selectively applied. The timer means 34 includes a print timer 35, a pause timer 36, and a power-off timer 3.
8 are configured. The print timer 35 is a timer for measuring the duration of the printing operation, and is started from the start of printing and reset by a flushing operation. Pause timer 3
Reference numeral 6 indicates that the backup is performed by a temporary power supply or the like so that the time can be measured even after the main power supply SP is turned off, and the time is started when the printing operation is stopped and the recording head 16 is sealed by the capping device 18. Is reset when printing is started. The power-off timer 38 starts counting from the point in time when the power-on detection means 39 detects that the power switch SW has been turned off, and outputs the relay after the time required for sealing the recording head 16 by the capping device 18 has elapsed. The power supply of the main power supply SP to the apparatus is cut off by deenergizing 40.

(Other Embodiments) In the above embodiment, the recording head 16 changes the volume of the pressure generating chamber 113 communicating with the nozzle 11 by using a piezoelectric vibrator PZT or the like to change the volume of the ink droplet. It was of the type that discharges ink, but the type that discharges ink droplets by changing the volume of the pressure generation chamber connected to the nozzle by vibrating the diaphragm using electrostatic force generated between the electrodes The present invention can also be applied to an object.

In the above-described embodiment, the face ejection type ejects ink droplets from the openings of the nozzles 111 provided on the lower surface of the substrate. However, the edge ejection type ejects ink droplets from the nozzle openings provided at the end of the substrate. It may be a type.

[0026]

As described above, in the ink jet recording apparatus according to the present invention, the vibrating plate is formed with the projections having the vertical surface directed toward the common ink chamber and the inclined surface directed toward the pressure generating chamber. Therefore, when the diaphragm is deformed to contract the pressure generating chamber, the vertical surface of the projection acts to shear the ink in the common ink chamber, and the slope of the projection in the pressure generating chamber Acts into the pressure generating chamber. Therefore, even when the diaphragm is deformed so as to shrink the pressure generating chamber, since a large pressure is not transmitted to the common ink chamber, ink droplets are ejected from nozzles which should not eject ink droplets this time. No problem (crosstalk) occurs. Also, in the pressure generating chamber, the slope of the projection acts to push the ink into the pressure generating chamber, so that the pressure due to the contraction of the pressure generating chamber (deformation of the vibration plate) is efficiently transmitted to the nozzle opening. . Therefore, since the ejection pressure of the ink droplet can be increased, there is also an advantage that the ink droplet can fly straight to a long distance.

[Brief description of the drawings]

FIG. 1 is an external view of an ink jet recording apparatus.

FIG. 2 is a perspective view showing a main part in a main body of the ink jet recording apparatus shown in FIG.

FIG. 3 is a perspective view of a recording head used in the ink jet recording apparatus shown in FIG. 1 when viewed from a lower surface side.

FIGS. 4A and 4B are cross-sectional views of a recording head used in an ink jet recording apparatus to which the present invention is applied,
FIG. 3 is a cross-sectional view of the recording head when the pressure generating chamber expands.

FIG. 5 is a block diagram of a control system and a drive system included in the inkjet recording apparatus shown in FIG.

FIGS. 6A and 6B are a cross-sectional view of a recording head used in a conventional ink jet recording apparatus and a cross-sectional view of the recording head when a pressure generating chamber is expanded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording apparatus 2 IC 3 Tray conveyance table 10 Recording apparatus main body 11 Carriage 16 Recording head 20 Package surface 110 Nozzle plate 111 Nozzle 112 Flow path forming plate 113 Pressure generation chamber 114 Ink supply port 115 Common ink chamber 116 Vibration plate 118 Flow path Unit 120 Projection 121 Vertical surface 122 Slope 125 Thin part PZT Piezoelectric vibrator (pressure generating element) TR Tray

Claims (2)

[Claims] 1. A pressure generating chamber communicating with a nozzle opening, and a diaphragm constituting one wall surface of the pressure generating chamber are deformed to contract the pressure generating chamber and eject ink droplets from the nozzle opening. In an ink jet recording apparatus having a plurality of pressure generating elements and having a common ink chamber which communicates with the plurality of pressure generating chambers and supplies ink when the respective pressure generating chambers expand, the diaphragm includes the pressure generating chamber and the pressure generating chamber. An ink jet recording apparatus, wherein a projection is formed in a portion communicating with the common ink chamber so as to face a vertical surface toward the common ink chamber and a slope toward the pressure generating chamber. 2. The method according to claim 1, wherein the slope of the projection is
An ink jet recording apparatus, wherein the angle is about 45 ° with respect to the diaphragm.