JPH0357870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet device that performs desired recording by ejecting ink from a recording head, and particularly to an inkjet equipped with an ink container that can be refilled with ink.

Among the various recording methods currently known, this non-impact recording method generates almost no noise during recording, is capable of high-speed recording, and can record on plain paper without requiring any special fixing process. The so-called inkjet recording method that can be used is an extremely useful method for realizing printing devices such as various printers, copying devices, and word processors. Various methods have been proposed for this inkjet recording method, some have been improved and commercialized, and others are still being worked on to put them into practical use. .

In the inkjet recording method, droplets of recording liquid (referred to as ink in the explanation of the present invention) are ejected using various working principles, and the droplets are attached to a recording material such as paper to perform recording. This is what we do. An ink droplet generating device, that is, an inkjet device, used in such an inkjet recording system generally consists of an inkjet head for forming ink droplets and an ink supply system for supplying the ink to the inkjet head.

By the way, the first form of the ink jet head is generally called a single type or semi-multi type, which has about 1 to 10 ink ejection ports. The supply system is (because there are fewer ink ejection ports and less ink consumption)
It can be configured relatively easily by using a cartridge-type replaceable ink tank and a single ink supply pipe.

However, the ink supply system for another type of head, generally called a full-line multi-type head, which is used for the purpose of printing one line of paper almost simultaneously, has an extremely large number of ink ejection ports, The amount of ink consumed will also be incomparably greater than in the case described above, so the former ink supply system may become complicated and large, or require separate ink replenishment. Compare,
It is quite technically difficult.

For example, if ink is simply poured into an ink tank from the outside, the ink interface will ripple due to the influence of the poured ink. Since it takes time for such a waving phenomenon to subside, this is not preferable from the viewpoint of operability of the recording apparatus. Furthermore, in a state where the waving phenomenon occurs, there is a possibility that stable ink supply to the recording head may not be achieved.

Therefore, it is difficult to find a highly practical ink supply system for such an inkjet device called a full-line multi-type inkjet device.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-mentioned problems in the prior art and provide a highly practical ink supply device for a multi-type inkjet device.

That is, a first object of the present invention is to provide an inkjet device that can stably supply ink for a long time to multiple types of recording heads.

A second object of the present invention is to provide an inkjet device for stably supplying ink almost uniformly to the entire area of a multi-type recording head.

Furthermore, a third object of the present invention is to provide an inkjet device equipped with an ink supply device that is easy to maintain and manage.

As a result of intensive studies to achieve the above-mentioned object, the inventors of the present invention discovered that the ink replenishment area (first area) of the ink tank where ink is replenished and the area (second area) for supplying ink to the recording head. It has been found that the movement of air from the first region to the second region can be suppressed by moistening the filter member with ink through the filter member during this period.
In addition to the effect of suppressing the transmission of the undulations of the filter itself, this also suppresses the movement of air, making it even more difficult for the undulations of the ink surface to be transmitted. We also found that it is very stable.

The present invention was made based on the above-mentioned findings,
The first ink container stores ink to be supplied to the ink jet head and has first and second regions divided by a filter member so as to intersect with the liquid level of the stored ink. an ink inlet connected to an ink replenishment container storing ink to be refilled in the ink container;
A vent hole is provided for communicating the first region with the atmosphere, and an ink supply means for supplying ink to the ink jet head is provided in the second region. an inkjet device, wherein the first inkjet device
By introducing atmospheric air into the region, ink is replenished from the ink replenishing container, and the filter is moistened by the supplied ink, so that air moves from the first region to the second region. The present invention is characterized in that ink is supplied to the ink jet head using capillary force in a state where ink is substantially suppressed.

When the filter placed inside the ink tank becomes wet with ink, it divides the area where air exists and creates a state in which mutual movement of air is suppressed. As a result, in addition to the effect of suppressing state changes caused by the presence of the filter itself, changes in the state that occur on the ink replenishment region (first region) side, such as sudden supply of ink due to replacement of the replenishment tank, are suppressed by the air movement described above. Since the suppressing effect is added, the state change is further suppressed, and the ink supply area (second area) to the recording head is
The stabilization of the presence of ink can be ensured. Also, since the ink is filtered by a filter,
Ink containing almost no impurities can be supplied to the second region. Therefore, it is possible to create a state in which disturbances are extremely suppressed on the second region side, so that the effect of capillary force used for supplying ink to the recording head can be stably exerted.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a schematic diagram illustrating an overview of the present invention.
In Figure 1, 101-1, 101-2,...,10
Ink jet heads 1-n are each provided with a plurality of ejection ports 103 for ejecting and flying ink, and an ink relay chamber 102 communicating with the ejection ports 103. 113-1, 113-
2,...,113-n and 114-1,114-
2,..., 114-n transfer the ink 105 in the ink tank 104 to each of the heads 101-1, 101-n.
2, ..., 101-n, and the supply pipes 113-1, 113-2, ..., 113-
n has check valves 115-1, 115-2,...,
115-n and 116-1, 116-2,...,1
16-n is attached. Ink tank 104
is provided with an ink replenishment port 112 and a ventilation hole 106, and this ventilation hole 106 is connected to the filter 1.
It communicates with the atmosphere via 07. Inside the tank 104, there is a side where the ink refill port 112 is located and a side where the supply pipes 113-1, 113-2, ..., 113-n and 114-1, 114-2, ..., 114-n are located. A filter 108 is provided to partition the area. 118 is a cylinder block, inside which the heads 101-1, 101-2, . . .
Cylinder 119-1, 1 corresponding to 101-n
19-2, . . . , 119-n are provided. Each of these cylinders has a passage 117-1, 117
-2,..., 117-n via the non-return valve 115
and 116, the supply path 113-1, 113-
2,..., 113-n. Also, inside each cylinder are pistons 120-1, 120-2,
..., 120-n are inserted. Reference numeral 109 denotes an ink replenishment tank that is detachable from the tank 104, and a liquid level control valve 111 is attached to this tank.

Ink is supplied from the ink tank 104 to the ink jet heads 101-1, 101-2, . . . , 101-n as follows. First, from the ink tank 104 to the ink jet head 101-1,1
Initial filling of ink is performed for 01-2, . . . , 101-n. When initially filling a predetermined head, the replenishment tank 109 filled with ink is connected to the ink replenishment port 112 of the ink tank 104 in advance. At this time, the liquid level control valve 111 is opened, and the ink in the replenishment tank 109 naturally falls into the ink tank 104 while being replaced with air. When the ink level in the ink tank 104 reaches the position of the liquid level control valve 111, the opening of the liquid level control valve 111 is blocked with ink, so the ink in the refill tank 109 is no longer replaced with air, and the refill tank 109 is closed. Transfer of ink from 109 to ink tank 104 is stopped. Incidentally, from the replenishment tank 109 to the ink tank 104
When the ink naturally falls into the ink tank 104,
Since the filter 108 inside is wetted with ink, air does not move from area B to area A of the ink tank 104. Also, this filter 10
Since particles such as dust and air bubbles mixed in the ink are removed from the ink passing through step 8, temporarily,
Even if these particles and air bubbles are mixed in the ink in the replenishment tank 109, the particles and bubbles will not enter the B area of the ink tank 104. Therefore, the causes of ink ejection failure are completely removed from the ink supplied from the B area to the head 101-1.

When the ink tank 104 and the refill tank 109 are connected via the O-ring 110, or when the connection between the ink tank 104 and the refill tank 109 is blocked with ink, the ink tank 1
If air is not replenished into the A area of the ink tank 104, the ink will not transfer from the A area to the B area of the ink tank 104.
The ink levels in area A and area B are not the same. For this reason, the ventilation hole 10 of the ink tank 104
6 is the ink replenishment port 1 with the filter 108 as the border.
It must be on the same side as 12. Further, the ink level in the ink tank 104 must be set so that the ink pressure in the head becomes negative so that the ink does not spontaneously leak out from the ejection port 103 of the ink jet head. In this way, with the ink tank 104 filled with ink, the specified piston 120-1 is pushed in the direction of the arrow, and the cylinder 119
- After removing the air in 1 through passage 117-1, pull piston 120-1 (in the opposite direction of the arrow)
and the ink in the ink tank 104 flows through the check valve 1.
16-1, cylinder 1 through passage 117-1
Inhaled into 19-1. Then the piston 120
-1 in the direction of the arrow, cylinder 119-1
The ink inside passes through the passage 117-1 and the backflow prevention valve 115.
-1, is press-fitted into the ink jet head 101-1 through the supply pipe 113-1. When the piston 120-1 is operated in this way, the ink jet head 101-1 is filled with ink, and the supply pipe 114-1 is filled with ink.
1 to the ink tank 104 through the supply pipe 11
The process is continued until the air (bubbles) in the inkjet head 101-1 and the inkjet head 101-1 are completely eliminated. Then, a predetermined inkjet head 1
After the ink is filled into the inkjet head 101-1, the ink is supplied by capillary force through the supply pipes 113-1 and 114-1 when the ink jet head 101-1 is activated to eject ink droplets. will be done.
Therefore, the check valves 115-1 and 116-1 must be opened with a slight normal pressure, and the ink level in the ink tank 104 must not be extremely low compared to the position of the ink jet head 101-1. Undesirable, practical inkjet head 1
It is desirable that the difference in ink level between 01-1 and the ink tank 104 is within a range of approximately 0 to 100 mm.

If stable ejection cannot be obtained due to air bubbles or dust getting into the ink jet head 101-1, fill the ink tank with the same operation method as when initially filling the ink jet head 101-1 with ink. 104 and inkjet head 101
It can be easily recovered by circulating between -1. The above explanation is for the sake of convenience.
I went to 01-1, but other heads 10
1-2, . . . , 101-n, the initial filling of ink, the ink supply during operation, and the recovery of ink discharge can of course be performed using the same operating method as described above.

Next, one embodiment of the present invention will be described using FIG. 2.

FIG. 2 is an exploded view of an ink supply device as an application example of the example shown in FIG.

In FIG. 2, 201 is an ink tank, which includes an ink container 202, a packing 203, and a top lid 204.
It consists of A filter 205 and a plurality of check valves 206 are installed inside the ink container 202, each of which has an ink supply pipe 20.
7,208 is attached, and the ink container 202
A pipe guide 209 is attached to the front side, and a cylinder block 210 is attached to the rear side.

The upper lid 204 includes an ink refill port 211, a vent block 212, and an ink refill tank holder 213.
and 214 are attached, and a filter block 215 is attached to the vent block 212.

Ink container 202, packing 203, top lid 2
04 are combined by being pressed together by screwing or the like. In addition, the ink container 202 and the upper lid 204
can also be integrated by joining,
In that case, packing 203 is not necessarily necessary.

216 is a multi-nozzle ink jet head, and ink supply tubes 217 and 218 communicate with the inside of the ink tank 201 via ink supply pipes 207 and 208, respectively.

219 is an ink replenishment tank, and a part thereof includes an ink replenishment port 2 on the top cover 204 of the ink tank.
an ink injection device 22 for refilling ink at a constant ink level into the ink tank 201 via 11;
It has 0. The ink replenishment tank 219 is detachable from the ink tank 201 and can be replaced as needed.

Ink is supplied from the ink tank 201 to the multi-nozzle ink jet head 216 as follows. First, the multi-nozzle ink jet head 216 is initially filled with ink from the ink tank 201. When performing initial filling of ink, use the injection device 220 of the ink replenishment tank 219.
After connecting the ink tank 201 to the ink replenishment port 211 and installing the tank 219 on the top lid 214, the tank 219 is attached to the tank holders 213 and 21.
Fix it at 4. At this time, the ink replenishment tank 21
The ink injection device 220 attached to the ink tank 201 is operated and ink is injected into the ink tank 201 up to a fixed ink level. Note that the ink refill port 211 and the vent block 212 are arranged on the same side of the filter 205 so that the ink level on both sides of the filter 205 (which acts in the same manner as the filter 108 in FIG. 1) is equal. has been done.

FIG. 3 shows the check valve 20 shown in FIG.
FIG. 2 is a sectional view taken along the lines X and X', illustrating the detailed structure of the cylinder block 210 and the cylinder block 210. In FIG. 3, an ink tank 301 is composed of an ink container 302, a packing 303, and an ink tank top lid 304. ink tank 3
A check valve 305 is installed in the check elbow 306, and the check valve 305 is connected to valve supports 307 and 30, respectively, in the check elbow 306.
8. Valve 309, 310, valve receiving part 311, 312
This structure has two check valves 313 and 314 arranged at right angles.

315 is a cylinder block, and after a spring 317, a spring receiver 318, and a piston 319 are inserted into the cylinder 316, its open end is closed with a cylinder lid 320. piston 31
9 has an O-ring 321 and a removable rod 3.
22 is attached. Cylinder 316 communicates with ink flow path 324 between check valves 313 and 314 in check valve 305 through a joint 323 . Incidentally, 328 and 329 are packings for preventing ink leakage.

Reference numeral 330 is an ink supply pipe for connecting the check valve 305 and an ink supply tube (not shown), and is fixed to the check valve 305 and the ink container 302 by support members 331 and 332, respectively. In addition, sleeves 333 and 334 are provided to prevent movement of the ink supply pipe 330 due to attachment and detachment of the ink supply tube. 335 is a pipe guide that prevents the support member 332 from coming off and securely fixes the ink supply pipe 330. By injecting a sealing material or the like into the pipe penetration hole 336,
Ink leakage from around the ink supply pipe 330 can be completely prevented. 337 is an ink supply pipe for connecting other ink supply tubes.

When the piston 319 is pushed toward the left in the drawing by the rod 322 with the ink tank 301 filled with ink, the air in the cylinder 316 flows into the passage 32.
5, 324, 326 and after opening valve 310, it is removed from passage 327 through ink supply pipe 330. When the pressure on the piston 319 is released, the piston 319 is pushed back by the spring 317, and the valve 310 is closed by the suction pressure of the cylinder 316. At the same time, the valve 309 is opened and the ink in the ink container 302 flows into the ink flow path 323, 32
4,325 into the cylinder 316. After the ink has been sucked into the cylinder 316 in this way, when the piston 319 is pushed again toward the left in the drawing, the valve 309 is closed and the valve 310 is opened, so that the ink sucked into the cylinder 316 is absorbed into the cylinder 316. Passage 325, 324, 326, 3
The ink is supplied from an ink supply pipe 330 through an ink supply tube 27 to an ink jet head (not shown in FIG. 3). In this manner, the initial filling of ink from the ink container 302 to the ink jet head is performed until the ink jet head, ink supply tube, and ink supply pipe are filled with ink and there are no air bubbles in the ink supply path.

At this time, in order to ensure the operation of the valves 309 and 310 and prevent leakage due to back pressure, the valve receiver 311 is
The portions of and 312 in contact with the valves 309 and 310 are arranged to form the same plane as the valves 309 and 310, and have a smaller area than the valves 309 and 310.

Further, the passage 325 is provided below the center of the cylinder 316 so that the air remaining in the cylinder 316 due to the operation of the piston 319 does not flow into the passage 325.

When an ink jet head (not shown) operates to eject ink droplets, ink is supplied from the ink tank 301 through ink supply pipes 330 and 337 by capillary force. Therefore, the valves 309 and 310 are designed to open at a slight normal pressure, and the ink level in the ink tank 301 is set so that the ink pressure at the head becomes negative pressure. In the embodiment shown in FIG. 2, check valves having the same structure and operating in the same manner as the check valve 206 described above are arranged in parallel in the ink container 202 in the same number as the number of ink jet heads (not shown).

In this embodiment, the ink supply path (the path of the valve 206, the pipes 207, 208, and the tube 21) to each ink jet head is
Since the lengths (total sum of 7,218) are all approximately the same, it can be considered that there is almost no difference in the supply pressure of ink supplied to each ink jet head by capillary force.

Although not shown in FIG. 2, the same number of cylinders 316 and pistons 319 as shown in FIG. 3 are installed in the cylinder block 210, corresponding to each check valve 206. It has been done.

By integrating the cases of each cylinder in this way, the mechanical strength of each cylinder is increased, and
It becomes easy to fix the connection between each cylinder and its corresponding check valve, and it is possible to prevent the cylinder from falling off from the ink tank.

As explained in detail above, in the present invention, since an ink supply system of almost the same standard is provided for each of a plurality of inkjet devices, it is possible to uniformly and stably supply ink to the entire area of a multi-type inkjet device. It's big.

Further, in the present invention, since the ink supply source for the plurality of inkjet devices is unified,
It is easy to replace ink containers, and
The required frequency is also less.

Furthermore, since the present invention adopts a distribution replenishment method for a plurality of ink jet devices, it is possible to replenish the appropriate amount of ink without any impurities almost automatically according to the amount of ink consumed in the main tank. Replenishment time is extremely low. Various effects can be mentioned.

Further, according to the present invention, the filter disposed in the ink tank becomes moist with ink, thereby dividing the area where air exists and suppressing mutual movement of air. As a result, in addition to the effect of suppressing state changes caused by the presence of the filter itself, changes in the state that occur on the ink replenishment region (first region) side, such as sudden supply of ink due to replacement of the replenishment tank, are suppressed by the air movement described above. Because of the added suppressing effect, it is possible to provide an ink jet device that can further suppress state changes and ensure stabilization of the presence of ink in the ink supply area (second area) to the recording head.

In addition, since the ink is filtered by the filter, it is possible to provide an inkjet device that can replenish the second region with ink containing almost no impurities.

In this way, the present invention can create a state in which disturbances are extremely suppressed in the area where ink is supplied to the recording head, so that the action of capillary force used to supply ink to the recording head can be stably exerted. It is possible to provide an inkjet device that can perform

[Brief explanation of drawings]

FIG. 1 is a schematic view showing an embodiment of the ink supply device of the present invention, FIG. 2 is an exploded view illustrating an applied example of the embodiment shown in FIG. 1, and FIG. 3 is a sectional view of the applied example shown in FIG. In the figure, 101-1, 101-2,...101
-n, 216 is an ink jet head, 102 is an ink relay liquid chamber, 103 is an ejection port, 104, 20
1,301 is an ink tank, 105 is an ink, 1
06 is a vent, 107, 108, 205 is a filter, 109, 219 is an ink refill tank, 11
0,121-1,121-2,...121-n,3
21 is an O-ring, 111 is a liquid level control valve,
112, 211 are ink refill ports, 113-1, 1
13-2,...113-n, 114-1, 114-
2,...114-n is an ink supply pipe, 115-1,
115-2,...115-n, 116-1, 116
-2,...116-n, 313, 314 are check valves, 117-1, 117-2,...117-n, 3
23, 324, 325, 326, 327 are ink passages, 118, 210, 315 are cylinder blocks, 119-1, 119-2,...119-n,
316 is a cylinder, 120-1, 120-2,
...120-n, 319 is a piston, 202, 30
2 is the ink tank body, 203, 303, 32
8,329 is packing, 204,304 is ink tank lid, 206,305 is check valve,
207, 208, 330, 337 are ink supply pipes, 209, 335 are pipe guides, 212 are vent blocks, 213, 214 are ink refill tank holders, 215 are filter blocks, 21
7, 218 is an ink supply tube, 220 is an ink injection device, 306 is a check elbow, 307,
308 is a valve support part, 309 and 310 are valves, 31
1, 312 is a valve receiver, 317 is a spring, 318 is a spring receiver, 320 is a cylinder lid, 322 is a rod, 323 is a joint, 331, 332 are support members,
333 and 334 are sleeves, and 336 is a pipe penetration hole.

Claims (1)

[Scope of Claims] 1. An ink jet head which stores ink supplied to the ink jet head and has first and second regions divided by a filter member so as to intersect with the liquid level of the stored ink. The first region of the ink container includes an ink inlet connected to an ink replenishment container storing ink to be refilled in the ink container, and a vent hole that communicates the first region with the atmosphere. , and the second
The ink jet device is provided with an ink supply means for supplying ink to the ink jet head in the ink jet head, and the ink replenishment container is filled by introducing atmospheric air into the first region through the vent hole. The ink jet head is refilled with ink and the filter is wetted by the supplied ink, thereby substantially suppressing the movement of air from the first area to the second area. An inkjet device characterized by supplying ink to the ink using capillary force.