JPS6026713B2 - Inkjet device - Google Patents

Description

[Detailed description of the invention] The present invention relates to an inkjet device.

In inkjet devices in which ink droplets are forced out of a pressurized chamber by selectively increasing the pressure within the chamber, the means for increasing the pressure within the chamber may be a piezoelectric actuator or a magnetostrictive actuator. It is an actuator.

Since these actuators are usually permanently fixed to the inkjet device, it is necessary to replace the actuator with a new one each time the inkjet device is replaced. Furthermore, this actuator occupies a very large portion of the cost of the entire inkjet apparatus. Therefore, if the actuator can be reused, the cost can be reduced considerably by reusing the previous actuator when replacing the inkjet device. Therefore, an object of the present invention is to removably attach a magnetic or piezoelectric means to a liquid droplet extrusion device so that even if the liquid droplet extrusion device is replaced, the previously used magnetic or piezoelectric drive body can be used. An object of the present invention is to provide an inkjet device that can perform the following functions. Another object of the present invention is to provide a liquid full extrusion device of simple construction which is removably attached to a magnetic or piezoelectric drive means.

Another object of the invention is to construct a liquid droplet extrusion device particularly suitable for use in inkjet applications.

Other objects of the invention will become apparent from the description of the embodiments shown in the accompanying drawings.

1-4, a multiplex inkjet printing device is positioned against a rotating recording medium 12 for depositing ink droplets thereon.

This printing device consists of a drive unit 14 that is detachably attached to the main body of the device, and an inkjet unit 10 that is detachably attached to this unit. 16, a plastic or ceramic multi-nozzle unit 18 mounted on the front of the chamber housing, and a plastic or ceramic manifold/reservoir unit 19 mounted on the back of the chamber housing. The chamber housing 16 has a large number of rectangular chambers 20 separated by side walls 21 projecting upward from a bottom wall 22. Thin elastic diaphragm 24 stretched in the chamber
are sealed on top of each wall 21 to form the outer wall of the chamber. This elastic diaphragm 24 is
Made of resilient material such as stainless steel, glass or nickel. The drive unit 14 supports an elastic conductive metal web 26, a plurality of piezoelectric ceramic members 28 joined to the web 26 and separated from each other in the longitudinal direction, electrodes 30 respectively joined to the piezoelectric members, and an inkjet unit. It consists of a carrier bar 32 made of ceramic or plastic that serves as a support member.

The piezoelectric portion 28 and the electrode 30 are most preferably circular, but may also be square or rectangular. Piezoelectric village 2
8 is polarized to contract radially during its manufacture. A number of lead wires 34 are each connected to each electrode 30, and another IJ wire 36 is connected to the web 26. The leads 34, 36 are connected to an electrical driver (not shown) so that the electrodes 30 of each piezoelectric section can be individually addressed. Carrier bar 32 includes a number of cylindrical cavities 38, each cavity having its closed end fairing 41.
It has a raised portion 40 on top. This raised part, 4 rivers, draws a circle on the wall 41. The surface of the raised part is
A distance "d" from the surface 42 of the bar 32 (this distance is less than the total thickness "t" of the electrical member 28 and the electrode 30)
It is located only in one place. The metal web 26 is adhered to a portion of the surface 42 of the carrier bar by a known adhesive. Note that the adhesive portion of this bar is a portion located between the cavities 38 so as to engage and press the electrodes 30 with the raised portions 40. Piezoelectric member 28 and electrode 3
Because of the difference between the total thickness "t" and the distance "d" between surface 42 and ridge 40, web 26 will deform somewhat when bonded to carrier bar 32. A flange 44 is provided at each longitudinal end of the carrier bar 32, which serves as a support section, and the chamber housing 1
At each longitudinal end of 6, a flange 46 is provided which interlocks with the flange described above.

The carrier bar 32 and the chamber housing 16 are
In this example, it is removably attached by bolts 50 and nuts 52 to longitudinally spaced support flanges 48 (only one shown) located at each adjacent longitudinal end thereof. The degree of deformation of the web 26 due to the protrusion of the diaphragm member 28 beyond the surface 42 is such that when the carrier bar 32 and chamber housing 16 are assembled together, the diaphragm wall assumes the shape of the deformed web 26 in its normal position. This is the extent to which the diaphragm 24 is distorted when the alignment is ensured. Applying a voltage to the piezoelectric member causes it to deform, causing a similar deformation in diaphragm 24, reducing the volume of chamber 20 and expelling ink droplets therefrom. When the voltage application is stopped, the diaphragm 24 returns to its normal position due to its elasticity, and the volume within the chamber 20 also returns to its original state. The multi-nozzle unit 18 is of thin plastic wall construction and consists of multiple orifices for inkjet droplets separated by walls. This nozzle unit includes a number of vertical edges 55 sealed to the front portion of the diaphragm 24.
and the nozzle unit has one orifice.
Suitable for chamber and lotus, side wall 21 and bottom wall 22
It is sealed by. The manifold ink reservoir unit 19 is also of thin plastic wall construction and has a number of septum edge greens 57 sealed to the rear end of the diaphragm 24.

This reservoir unit is also sealed to the side walls 21 and bottom wall 22 and communicates with the individual chambers 20 through a number of orifices. Reservoir orifice 56
is constricting the flow from the chamber more strongly than the droplet orifice 56, so that the pressure created in the chamber 20 due to the deformation of the diaphragm 24 is forced through the orifice 56 and into the reservoir. This will overcome the fluid pressure returning to force the droplets out of the nozzle orifice 54. When the diaphragm relaxes, fluid from the reservoir replaces the ink forced out of chamber 20. The primary reservoir 58 supplies liquid to the manifold reservoir via conduit 60 and is maintained at a pressure of approximately 6 inches in the liquid column. In operation, a voltage is selectively applied to the indentation members 28 of various selected chambers, which deform the diaphragm 24 to force an ink droplet from the associated nozzle orifice 54.

The ink droplets adhere to the recording medium 12 in a desired twill shape as the recording medium 12 rotates past the inkjet unit 10 . If you want to replace the inkjet unit 10, remove the unit 10 and drive unit 14 from the support flange 48, replace the inkjet unit 10, and attach the new inkjet unit and old drive unit to the support flange 48.
Attach to.

Since the piezoelectric member can be reused for a large number of inkjet devices, the cost is reduced compared to the case where a new piezoelectric member is prepared for each inkjet device. Reference is made to FIGS. 5 to 7, which illustrate simultaneous inkjet devices to which the present invention can be applied.

Regarding this simultaneous inkjet device itself, the special IsoSho 51 on a simultaneous inkjet device having two ink pressurizing passages and one ink droplet ejection orifice is described.
Please refer to specification No. 113035. In this case, each pressurizing passage passes through each pressurizing chamber, and ink particles flow only when the pressures of both pressurizing passages rise simultaneously.
Discharged from the orifice. Referring to FIG. 7, which shows a cross-section of an inkjet unit housing 100 that includes a pair of circular pressure chambers 101 and 102, main fluid pressure passages 104 and 105 are connected to chambers 101 and 102, respectively.
102 to pressure inlet passages 106 and 107, which in turn communicates with an ink application groove passage 108, where the three pilgrims intersect.

The liquid ink supply passage 108 branches from two parallel main supply V supply passages 1 10, 1 12 which further form an intersecting passage 1 at one end within the housing.
14 and at the other end a C-shaped outer tube fitting 1
16. An ink reservoir 120 consisting of a flexible bag is connected to the tubular fitting 1 by a conduit 122.
16, and there is an ink droplet 1 at the intersection.
There is a discharge orifice 124 that extrudes 26 onto the copy media. Each chamber 101, 102 is sealed by a resilient diaphragm 128 attached to the housing 100 with a suitable adhesive, and the entire chamber and passageway is filled with liquid.

As the diaphragm 128 of either chamber 101 or 102 deforms, the pressure within that chamber increases, forcing ink into either passageway 106,107. The chamber, passage and droplet discharge IJ described above
The purpose of this relationship is to help you understand the principle of the simultaneous inkjet system.

The mutual angular relationship of passages 106 and 107 and orifice 124 is determined by the fluid resistance within passage 108 and the orifice 124.
The magnitude and duration of the rising pressure applied to the liquid in the pressurized chambers 101 and 102 are determined by the relationship with the fluid resistance within the pressure chambers 101 and 102, and the ink flow into the orifice 124 is determined by the ink flow pushed out from only one passage. The ink is not pushed out but only moves into the ink stream 108, and
It is determined so that the ink within the orifice 124 does not disturb the degree of extrusion of the ink bottle drops therethrough.
The orifice 124 also depends on its location with respect to the intersection of the passages 106 and 107, and the magnitude and duration of the increased pressure on the liquid in the chambers 101 and 102.
The resultant vector of the moment vectors of the fluid in the fluids 6 and 107 is determined to be on the axis of the orifice 124. Therefore, the diaphragms 128 for both pressurized chambers 101 and 102 are deformed simultaneously, and both passages 10
An ink droplet will be forced out of orifice 124 only when a simultaneous increase in pressure of the liquid in 6,107 is achieved. The principle of the simultaneous inkjet system described above allows the number of pressurized chambers to be significantly reduced compared to the number of jets in a matrix system that employs a large number of jets or a high-density linear jet array. Therefore, it is particularly useful.

Basically, two independent pressure chambers are required to extrude one ink droplet from one jet, so the number of pressure chambers required in the matrix method is: It is twice the square root of the number of jets. For example, typically only 120 pressurized chambers are required for 3600 jets. Each jet orifice accommodates two pressurized chambers. However, since the number of jets in one inkjet system is extremely large, the number of jet orifices that can fit in one pressurized chamber is limited by fluid pressure, so in reality, even more pressurization is required. Requires chamber.
For example, in one with 3600 jet nozzles, the number of pressurized chambers required ranges from 120 to 40 pressure chambers. In this case, it is advantageous to provide multiple pressurized chambers in one housing to save on the number of ink jets in each chamber. The embodiment shown in FIGS. 5 to 7 is a 9-jet, 6-pressure chamber type inkjet 1.
It shows the unit. Each orifice 130, 13
2,134,136,138,140,142,144
has a pressure inlet passage 106 and a fluid supply passage 108 that extends through this circuit in exactly the same way as in the orifice 124, and pressurized chambers 146, 148, 1
50 and 152 are the same as chambers 101 and 102, each sealed with an individual diaphragm 128. For further clarity, FIG. 5 shows the fluid passages between chambers 101, 146, 148 and their inkjet orifices, and FIG. The fluid passageway to and from the orifice is shown. Further, in these drawings, in order to clarify the individual passages, some of them are hatched and dotted. The chamber 101 has a main passage 104 and a jet 124.
, 134 and 14, chamber 146 is connected to passage 15.
4 to jets 130, 136, and 142; chamber 148 connects jets 132, 138, 14 to passage 156;
2, the chamber 102 is connected to the jet 12 in the passage 105.
4,130,132, chamber 15, passage 15
8 to jets 134, 136, 138, chamber 1
52 are jets 140, 142, 144 in passage 160.
It is suitable for yogi. The table below shows from which jet an ink droplet is ejected when a particular chamber is pressurized. Simultaneous pressurization chamber droplet jets 102, 101
124102, 146 1301
02, 148 132150
101 1 I 150146
13615 and above 148
1 spot 152, 101 140
152, 146 142152
, 148 144 Referring to FIGS. 7 and 8, a pair of drive units 162 and 164 are removably attached to a stationary support 166.

Each drive unit is constructed similarly to drive unit 14, and the piezoelectric member 168 for each chamber is
Disposed within each cavity 170 of carrier bar 172 . An elastic metal web 171 is connected to each piezoelectric member and a carrier bar 172, and is connected to each diaphragm 1.
28 so as to apply a slight strain thereon. The electrically insulated lead wire 174 is connected to the pressure force member 1.
68, and another lead wire 178 is connected to the web 171. A large number of electronic drive units drive the desired piezoelectric member 1
68 to selectively apply a voltage to each lead 1
It is connected to 74,178. A voltage is applied to the piezoelectric members corresponding to the two chambers that are to be pressurized to expel a full drop of ink from a particular orifice and, if necessary, to expel the ink droplet from that orifice. This voltage application deforms the piezoelectric member and deforms the diaphragm 128, reducing the volume of the pressurized chamber and increasing the pressure inside the chamber. The device for creating suitable ink droplets includes a drive unit 16 having a flange 180 at the longitudinal end.
They are sandwiched between 2,164. The inkjet transceiver is attached to the stationary support structure 18 by means of bolts 182 extending between this flange and the support flange.
It has been set to 6. The inkjet unit was replaced with a new one, and in some cases, the drive unit 162,1
64 from the support flange 184 and the housing 100
is removed and replaced with a new unit, and then the drive unit is re-secured to the support flange 84. Therefore, the piezoelectric member can be reused for a large number of inkjet units, and costs can be reduced compared to the case where a new piezoelectric member is required for each unit. Although the diaphragm 24 in the embodiment shown in FIGS. 1-4 extends across the entire chamber housing, multiple separate diaphragms may be used for each chamber.

Additionally, a continuous diaphragm web is attached to the housing 10 to seal the chambers 101, 146, 148.
A separate diaphragm 128 is used for each chamber in the embodiment of FIGS. Good as a substitute. In another embodiment of FIGS. 9-11, an inkjet unit 200 is positioned opposite a rotating recording medium 400 for depositing ink droplets.

This unit 200 has a support section 300 of a magnetic drive unit detachably attached thereto. This unit 20
0 is an elongated plastic or ceramic chamber housing 210;
A plastic or ceramic multi-nozzle unit 340 is attached to the front of the chamber housing, and a plastic or ceramic manifold/reservoir unit 350 is attached to the back of the chamber housing. The chamber housing 210 has a plurality of chambers 260 separated by side walls 280 protruding upward from a bottom wall 290. Elastic diaphragm 220 stretched in the chamber
are each side wall 2 so as to constitute the outer wall of the chamber body.
80 is sealed on the upper edge. The elastic diaphragm 220 consists of two laminated layers 222, 224 of two materials whose strain characteristics in the presence of a magnetic field are significantly different from each other. Therefore, when a magnetic field is applied, the diaphragm will bend. Examples of the two materials mentioned above include layer 222 made of nickel and the other layer 224 made of a cobalt-nickel iron alloy, e.g.
). The change in length with respect to the original length under a given magnetic force is much larger for supermendular than for nickel. When refraction of the diaphragm occurs, the supermendular layer becomes the longest surface (convex surface) of the ribbon in the direction of refraction, and the nickel becomes the shortest surface (concave surface). The support member 300 of the magnetic drive unit is
Bolts 2 passing through longitudinally spaced flanges 229
28 to a stationary support member 226.

The support member 30 is a material of high magnetic permeability but low electrical conductivity to minimize eddy current losses. Such materials are preferably from the group of materials known as ferrites. The support member 300 of the drive unit includes a large number of legs 230, and the adjacent pairs of legs constitute a horse-horizon type magnet that straddles each chamber 260. The portions 234 of the support member 300 located between each leg 230 are each coiled with a plurality of electrically insulated conductors. This coiled conductor is connected to an electrical driver (not shown)
, so each coil can be addressed separately. When current is passed through this coiled conductor, magnetic flux lines are generated in the axial direction of the coil, that is, in the longitudinal direction. Since the magnetic flux lines are isolated for each chamber region, only the portion of the diaphragm corresponding to the coil through which the current flows will be strained. The direction of this strain imparted on diaphragm 220 by the magnetic field is parallel to the magnetic flux lines, ie, in the longitudinal direction. Referring to Figure 10, due to the strain applied on the diaphragm,
A non-uniform strain occurs on the layers 222, 224, causing the diaphragm to bend in its longitudinal direction such that the side facing the interior of the chamber 160 is the convex longest surface 224, reducing the volume within the chamber. Then, the ink droplets are extruded from there. A multi-nozzle unit 34 of thin plastic wall construction has multiple orifices 238 for inkjet droplets separated by walls.

The nozzle unit has a number of septum edges 239 sealed to the front portion of the diaphragm 220, and the nozzle unit has a wall 180 and a bottom wall such that one orifice communicates with one chamber. 190 and is sealed. The manifold ink reservoir unit 350 is also of thin plastic disk construction and has a number of septum end greens 241 sealed to the rear end of the diaphragm 220.

This reservoir unit 350 is also sealed to side walls 280 and bottom wall 290 and has a number of orifices 240.
It is connected to the individual chambers 260 via. The reservoir orifice 240 narrows the flow from the chamber more strongly than the grain passing orifice 238,
The pressure created in the chamber 260 due to the deformation of the diaphragm 220 thereby overcomes the fluid returning through the orifice 240 to the reservoir, causing the nozzle orifice 23
Droplets will be extruded from step 8. When the diaphragm relaxes, fluid from the reservoir replaces the ink forced out of chamber 260. The primary reservoir 242 supplies liquid to the manifold reservoir via conduit 244 and is maintained at a pressure of approximately 6 inches in the liquid column. Due to the magnetic attraction between the inkjet unit 20, the horseshoe magnet and the diaphragm 220,
It can be detachably connected to the magnetic unit.

However, further suitable coupling means may be used to removably couple the device to the magnetic drive unit. This device 200 can therefore be removed from the drive unit and the same drive unit can be reused for other devices.
In operation, the coiled conductor 23 of a predetermined chamber is
2, the diaphragm 220 deforms and forces the ink droplet from the associated nozzle orifice 238.

The rotation of the ink droplets deposits them on the recording medium 400 passing through the orifice and forms an image thereon.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a multiplex inkjet printing device, FIG. 2 is a partial sectional view of a piezoelectric drive unit, and FIG.
FIG. 4 is a cross-sectional view taken along line 3--3 in FIG. 1, FIG. 5 is a top view of the simultaneous inkjet unit, and FIG. is a bottom view of the simultaneous inkjet unit in FIG. 5, and FIG. 7 is a bottom view of the simultaneous inkjet unit in FIG.
-7, FIG. 8 is a front view of the unit in FIGS. 5-7 showing the removable piezoelectric drive device. FIG. 9 is a perspective view of a multiple inkjet printing device having a magnetic drive device, and FIG. 10 is a perspective view of the line 22-2 in FIG.
2, FIG. 11 is taken along line 33-33 of FIG.
FIG. 10... Inkjet unit, 14... Drive unit, 16... Chamber housing, 18... Nozzle unit, 20... Chamber,
24...Elastic diaphragm, 28...
Piezoelectric member, 30...electrode, 32...carrier bar. F/G. /F/G, 2 F/G. 〆F/○. 4 F/G. 6 F/G. Evening F/○. 6 FIG. ll 'no G. 7 FIG. 9 FIG. l○

Claims (1)

[Scope of Claims] 1. A housing provided with a plurality of upwardly opening chambers formed by a partitioning side wall and a bottom wall, and provided with an elastic diaphragm for sealing the opening of each of the chambers; a support member adapted to removably support and disposed on a diaphragm of the housing and a diaphragm portion supported by the support member such that each support member is positioned on a diaphragm portion corresponding to the chamber; a drive unit that is removably attached to the device body and includes a plurality of drive means for deforming the chamber; and a drive unit that selectively biases the drive means of the drive unit to reduce the volume of the corresponding chamber. An inkjet device comprising: a biasing means for 2. The device according to claim 1, wherein the drive means comprises a piezoelectric member and electrodes arranged on the upper and lower surfaces of the piezoelectric member, the lower electrode being an elastic conductive web in contact with the diaphragm. 3. The device according to claim 1, wherein the drive means is a magnetic field generating coil wound around the support member, and the diaphragm is made of a magnetic material. 4. The device according to claim 3, wherein the support member is made of a permanent magnet and supports the housing by magnetic attraction.