JPH0357868B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording apparatus equipped with ink supply means for a recording head having a plurality of ink discharge ports.

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 machines, 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.

In addition to ensuring a stable supply of ink during recording, it is also necessary to ensure a stable and reliable supply of recovery ink for initial filling of the recording head with ink and recovery of the ejection state. At present, a high ink supply means has not yet been found.

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

That is, a first object of the present invention is to provide an apparatus for stably supplying ink for a long time to a multi-type inkjet recording apparatus during recording.

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

Furthermore, a third object of the present invention is to provide an inkjet recording device having an ink supply means that not only supplies ink to a recording head but also has functions for initial filling of ink and recovery of the ejection state. The purpose is to

The present invention has been proposed to achieve the above-mentioned object, and provides an inkjet recording head having a plurality of ejection ports arranged and a common liquid chamber communicating with the ejection ports; , a first ink flow path connected to one end side of the common liquid chamber, and a second ink flow path connected to the other end side of the common liquid chamber with respect to the arrangement direction of the ejection ports;
an ink jet in which ends of each of the first and second ink flow paths opposite to a connection end with the common liquid chamber communicate with each other independently; and an ink tank attached in the middle of the first ink flow path. a forced supply means for forcibly supplying the ink stored in the recording head to the recording head; when initially filling the recording head with ink, the forcible supply means is driven to supply the ink to the recording head; Ink supply means for forcibly supplying ink in one direction from the first ink flow path side, and when recording by the recording head, ink is supplied in both directions from the first and second ink flow paths using capillary action. It is characterized by having the following.

Two independent units between the ink tank and the recording head
Since the two ink channels communicate with each other and a forced ink supply means is provided in one of the ink channels, the ink can be forced to circulate, so initial filling of ink and recovery of supply can be easily performed. Further, during recording, good ink supply can be achieved using the capillary action of the two ink supply paths.

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,
..., 116-n are attached. The ink tank 104 has an ink refill port 112 and a vent hole 10.
6 is provided, and this vent hole 106 communicates with the atmosphere via a filter 107. In the tank 104, there is a side where the ink replenishment port 112 is located and a side where the ink replenishment port 112 is located, and supply pipes 113-1, 113-2, ..., 11.
3-n and 114-1, 114-2,..., 114
A filter 108 is provided to partition the side where -n is present. 118 is a cylinder block, inside of which are the heads 101-1, 101-1.
-2,..., cylinder 11 corresponding to 101-n
9-1, 119-2, . . . , 119-n are provided. Each of these cylinders has a passage 117-
1,117-2, ..., 117-n between the check valves 115 and 116, the supply path 113-1,
113-2,..., 113-n.
In addition, a piston 120-1, 1 is provided in each cylinder.
20-2, . . . , 120-n are inserted therethrough. 10
Reference numeral 9 designates an ink replenishment tank that is detachable from the tank 104, and includes a liquid level control valve 1.
11 is attached.

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 105 reaches the position of the liquid level control valve 111, the opening of the liquid level control valve 111 is blocked with ink, so that the ink in the replenishment tank 109 is no longer replaced with air, and the replenishment tank Transfer of ink from 109 to ink tank 104 is stopped. Incidentally, from the replenishment tank 109, the ink tank 10
When the ink naturally falls into the ink tank 10
Since the filter 108 inside 4 leaks ink,
Air no longer moves from area B to area A of the ink tank 104. 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 sealed with ink, air is not allowed to enter the A area of the ink tank 104. If it is not replenished, ink will not transfer from area A to area B of the ink tank 104, and the ink levels in area A and area B will not be the same. Therefore, the vent hole 106 of the ink tank 104 needs to be on the same side of the filter 108 as the ink refill port 112. 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, a predetermined piston 120-1 is pushed in the direction of the arrow, and after the air in the cylinder 119-1 is expelled through the passage 117-1, the piston 120-1 is pushed in the direction of the arrow.
-1 (in the opposite direction of the arrow) and ink tank 10
The ink in 4 flows through the check valve 116-1 and the passage 11.
7-1 into the cylinder 119-1. Next, when the piston 120-1 is pushed in the direction of the arrow, the ink in the cylinder 119-1 flows into the passage 1.
17-1, backflow prevention valve 115-1, supply pipe 113
-1 into the ink jet head 101-1. Such operation of the piston 120-1 causes ink to fill the ink jet head 101-1, and further reach the ink tank 104 via the supply pipe 114-1, and the supply pipes 113-1, 114-1 to be filled with ink.
1 and the ink jet head 101-1 until the air (bubbles) in the ink jet head 101-1 is completely eliminated. and,
After a predetermined ink jet head 101-1 is filled with ink, the ink jet head 101
-1 is activated to eject ink droplets, ink is supplied by capillary force through supply pipes 113-1 and 114-1. 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. Undesirably, in practice, the difference in ink level between the ink jet head 101-1 and the ink tank 104 is approximately 0 to 100 degrees.
It is desirable to be in the range of 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 has been given for the head 101-1 for convenience, but the other heads 101-2,...,1
Of course, in 01-n, initial filling of ink, ink supply during operation, and recovery of ink discharge can be performed using the same operating method as described above.

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

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

In FIG. 2, an ink tank 201 is composed of an ink container 202, a packing 203, and a top lid 204. A filter 205 and a plurality of check valves 206 are installed inside the ink container 202, and each of them has an ink supply pipe 207,
208, a pipe guide 209 is attached to the front side of the ink container 202, and a cylinder block 210 is attached to the rear side.

The upper lid 204 is provided with an ink refill port 211, a vent block 212, and ink refill tank holders 213 and 214.
12 is equipped with a filter block 215.

Ink container 202, packing 203, top lid 2
04 are combined by being pressed together by screwing or the like.

Incidentally, the ink container 202 and the upper lid 204 can also be integrated by joining, and in that case, the packing 203 is not necessarily required.

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 is equal.

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
It has a structure in which two check valves 313 and 314 are 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 3
19 is attached with an O-ring 321 and a detachable rod 322. Cylinder 316 communicates with an 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.

An ink supply pipe 330 connects 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.
is attached. Reference numeral 335 is a pipe guide that prevents the support member 332 from coming off and ensures the fixation of the ink supply pipe 330. By injecting a sealing material etc. into the pipe penetration hole 336, the area around the ink supply pipe 330 is fixed. Ink leakage 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 is 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 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 31 is
The portions of valves 1 and 312 that are in contact with valves 309 and 310 are arranged to form the same surface as valves 309 and 310, and have a smaller area than 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 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 connecting portion between each cylinder and the check valve thereto, and it is possible to prevent the cylinder from falling off from the ink tank.

As explained in detail above, according to the present invention, two ink supply pipes are independently connected to the recording head, and one of them is provided with forced supply means for forcibly supplying ink to the head. Therefore, it is possible to provide an inkjet recording apparatus in which initial filling of ink and recovery processing of the recording head can be easily accomplished by performing unidirectional supply.

Further, since ink is supplied during recording using capillary action through the two ink supply paths provided in the recording head, it is possible to provide an inkjet recording apparatus that can achieve extremely stable ink supply over a long period of time.

[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,...,10
1-n, 216 is an ink jet head, 102
103 is an ink relay liquid chamber, 103 is an ejection port, 104, 2
01,301 is an ink tank, 105 is an ink,
106 is a ventilation hole, 107, 108, 205 is a filter, 109, 219 is an ink refill tank, 1
10,121-1,121-2,...,121-
n, 321 is an O-ring, 111 is a liquid level control valve, 112, 211 is an ink refill port, 113-
1,113-2,...,113-n,114-1,
114-2,..., 114-n are ink supply pipes, 1
15-1, 115-2,..., 115-n, 116
-1,116-2,...,116-n,313,3
14 is a check valve, 117-1, 117-2,
..., 117-n, 323, 324, 325, 32
6,327 is an ink passage, 118,210,31
5 is cylinder block, 119-1, 119-
2,..., 119-n, 316 is a cylinder, 12
0-1, 120-2, ..., 120-n, 319 are pistons, 202, 302 are ink tank bodies,
203, 303, 328, 329 is Patsuking,
204, 304 are ink tank lids, 206, 30
5 is a check valve, 207, 208, 330,
337 is an ink supply pipe, 209, 335 is a pipe guide, 212 is a vent block, 213,
214 is an ink refill tank holder, 215 is a filter block, 217 and 218 are ink supply tubes, 220 is an ink injection device, 306 is a check elbow, 307 and 308 are valve supports, 30
9, 310 is a valve, 311, 312 is a valve receiving part, 3
17 is a spring, 318 is a spring holder, 320 is a cylinder lid, 322 is a rod, 323 is a joint, 33
1, 332 is a support member, 333, 334 are sleeves, and 336 is a pipe penetration hole.

Claims (1)

[Scope of Claims] 1. An inkjet recording head having a plurality of ejection ports arranged and a common liquid chamber communicating with the ejection ports, and connected to one end side of the common liquid chamber with respect to the arrangement direction of the ejection ports. a first ink flow path connected to the other end side of the common liquid chamber with respect to the arrangement direction of the ejection ports, and a second ink flow path connected to the other end side of the common liquid chamber, and the common liquid chambers of the first and second ink flow paths respectively. an ink tank whose ends opposite to the connecting end are both independently connected;
A forced supply means is provided in the middle of the first ink flow path for forcibly supplying the ink stored in the ink tank to the recording head, and the recording head is initially filled with ink. When doing so, the forced supply means is driven to supply the first
an ink supply means for forcibly supplying ink in one direction from the ink flow path side and supplying ink in both directions from each of the first and second ink flow paths using capillary action during recording by the recording head; An inkjet recording device characterized by comprising: 2. The inkjet recording head is a full-line multi-type inkjet recording head in which a plurality of inkjet recording heads each having a plurality of ejection ports arranged side by side are arranged so as to be able to print one line, and has a common liquid chamber communicating with the ejection ports. An inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is an inkjet recording head.