JPH0360672B2 - - 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. .

The inkjet recording method uses various working principles to fly droplets of recording paper (referred to as ink in the explanation of the present invention), and makes the droplets adhere to a recording material such as paper for 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. Moreover, it has not been sufficiently achieved to supply these inks almost equally and stably to a plurality of recording heads.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a highly practical ink supply means for an inkjet recording apparatus having a plurality of multi-type inkjet heads, by solving the above-mentioned problems in the prior art. do.

That is, a first object of the present invention is to provide an inkjet recording apparatus that can stably supply ink for a long time between a plurality of multi-type inkjet heads.

A second object of the present invention is to provide an inkjet recording apparatus that can stably supply almost uniform ink among a plurality of units equipped with multi-type inkjet heads.

As a result of intensive studies to achieve the above-mentioned object, the inventors of the present invention have decided to make the lengths of the ink flow paths between a plurality of units having recording heads and ink flow paths approximately equal between each unit. It was discovered that the conditions related to ink supply can be made consistent among each unit.

The present invention has been made based on the above-mentioned findings, and provides an inkjet recording head having a plurality of ejection ports arranged and a common liquid chamber communicating with the ejection ports, and regarding the arrangement direction of the ejection ports.
a first ink flow path connected to one end side of the common liquid chamber; 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; a plurality of ink jet head units each including a forced supply means attached to the ink tank midway and capable of forcibly supplying the ink stored in the ink tank to the recording head; an ink tank that stores ink and supplies ink to the recording head, and ends of each of the first and second ink flow paths opposite to the connection end with the common liquid chamber are both independently connected to each other. During initial filling, the forcible supply means is driven to supply ink in one direction from the first ink flow path, and when recording by the recording head, the first and second ink are supplied using capillary action. An inkjet recording device comprising an ink supply means for supplying ink in both directions from each of the ink passages, the length and length of each of the first and second ink passages being adjusted between each of the ink jet head units. It is characterized in that the ink supply pressures are substantially the same.

In this way, the length of the ink flow path and the ink supply pressure due to capillary action are made substantially equal between each of the plurality of ink jet head units including the first and third ink flow paths that supply ink to the recording head. Therefore, ink can be supplied extremely stably throughout each ink.

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. The tank 104 has 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, ..., 113.
-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;
The heads 101-1, 101-
Cylinder 119 corresponding to 2,..., 101-n
-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 lines 113-1, 11
3-2,..., 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 level 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. Transfer of ink from the ink tank 104 to the ink tank 104 is stopped. Incidentally,
When ink naturally falls from the replenishment tank 109 into the ink tank 104, the filter 108 in the ink tank 104 gets wet with the ink, so air does not move 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. For this reason, ink tank 1
The ventilation hole 106 of 04 needs to be on the same side as the ink replenishment port 112 with the filter 108 as a boundary. 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. After the predetermined ink jet head 101-1 is filled with ink, the ink jet head 101-1 is filled with ink.
1 is activated to eject ink droplets, ink is supplied through supply pipes 113-1 and 114-1 by capillary force. Therefore, the check valves 115-1 and 116-1 need to be opened by slight wind pressure, and the ink level in the ink tank 104 must be maintained at the ink jet head 101-1.
It is undesirable for the position to be extremely low compared to the position of
In practice, the difference in ink level between the ink jet head 101-1 and the ink tank 104 is approximately 0 to
It is desirable to be in the range of 100mm.

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. 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 a tank 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 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 of the upper lid 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 placing the tank 219 on the top lid 214, the tank 219 is connected to the ink refill port 211 of the ink tank 201
Fix it at 4. At this time, ink replenishment tank 2
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
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 3
19 is attached with an O-ring 321 and a detachable rod 322. Cylinder 316 communicates with ink flow path 324 between check valves 313 and 314 in check valve 305 through a joint 323. Incidentally, this is packing for preventing 328 and 329 ink from leaking.

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 securely fixes the ink supply pipe 330. By injecting a sealant or the like into the pipe penetration hole 336, the ink supply pipe 330 is fixed. It is possible to completely prevent ink leakage from around the area. 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 opened by the suction pressure of the cylinder 316.
is closed, the valve 309 is opened, and the ink in the ink container 302 flows into the ink channels 323 and 32.
4,325 into the cylinder 316. After sucking the ink into the cylinder 316 in this way, when the piston 319 is pushed to the left in the drawing again, the valve 309 is closed and the valve 310 is opened, so that the ink sucked into the cylinder 316 flows through the ink passage. 325, 324, 326, 327
The ink is supplied from the ink supply pipe 330 through the ink supply tube to an ink jet head (not shown in FIG. 3). In this manner, the initial filling of the ink jet head with ink from the ink container 302 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 to prevent leakage due to back pressure, the valve receiver 3 is
The portions of valves 11 and 312 that are in contact with valve 310 are valve 3.
It forms the same surface as valves 09 and 310, and has 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 the supply pressure of ink supplied to each ink jet head by capillary force. Although not shown in FIG. 2, the cylinder block 210 includes the same number of cylinders 316 and pistons 319 corresponding to each check valve 206, similar to those shown in FIG. There is.

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

As explained in detail above, according to the present invention, a plurality of ink jet head units each having an ink supply system of almost the same standard including first and second ink channels that supply ink to a recording head using capillary action can be used. Since the lengths of the ink flow paths are made substantially equal between each head unit and the ink supply pressures due to capillary action are made substantially equal, the ink supply conditions can be approximately equal for each head unit, resulting in extremely stable ink supply. It is possible to provide an inkjet recording device that can perform the following steps.

[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; 115-1,115-2,...,115-n,
116-1, 116-2,..., 116-n, 31
3,314 is a check valve, 117-1,117-
2,..., 117-n, 323, 324, 325,
326, 327 are ink passages, 118, 210,
315 is cylinder block, 119-1, 11
9-2,..., 119-n, 316 are cylinders,
120-1, 120-2,..., 120-n, 31
9 is a piston, 202, 302 is an ink tank body, 203, 303, 328, 329 is a packing, 204, 304 is an ink tank lid, 206,
305 is a check valve, 207, 208, 33
0,337 is the ink supply pipe, 209,335
is a pipe guide, 212 is a vent block, 21
3, 214 is an ink refill tank holder, 215 is a filter block, 217, 218 is an ink supply tube, 220 is an ink injection device, 306 is a check elbow, 307, 308 is a valve support part, 3
09, 310 is a valve, 311, 312 is a valve receiving part,
317 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 having 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 of the common liquid chamber with respect to the arrangement direction of the ejection ports; a plurality of ink jet head units each having a forced supply means for forcibly supplying the stored ink to the recording head; an ink tank in which ends opposite to the connection ends with the common liquid chamber of each of the first and second ink flow paths communicate independently; and when initially filling the recording head with ink, the forced The supply means is driven to forcibly supply ink in one direction from the first ink flow path, and when recording with the recording head, ink is supplied in both directions from each of the first and second ink flow paths using capillary action. An inkjet recording device comprising: an ink supply means for supplying ink, wherein the lengths and ink supply pressures of the first and second ink channels are substantially equal between each of the inkjet head units. An inkjet recording device characterized by the following.