JP2001225479A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent decrease in printing quality because of a level difference when recording heads are arranged in an up-down direction. SOLUTION: In this ink-jet recording apparatus, a plurality of the recording heads 4, 5 and 6 are disposed with height differences in the up-down direction and the ink is supplied to each of the recording heads 4, 5 and 6 through ink supply tubes 10, 11 and 12. Buffer tanks are connected between the recording heads 4, 5, 6 and the ink supply tubes 10, 11, 12. The buffer tanks are provided with valve mechanisms which open valves in accordance with a negative pressure generated when the ink of the recording heads 4, 5 and 6 is consumed. Differential pressures when the valves of the valve mechanisms are opened are set in accordance with the height differences of the recording heads 4, 5 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for performing printing while supplying ink from a main tank to a recording head with an ink supply tube.

[0002]

2. Description of the Related Art An ink jet recording apparatus for printing on a large-sized recording paper such as a poster supplies ink to a recording head of each color of a carriage from an ink cartridge of each color provided in the main body of the apparatus via an ink supply tube. It is configured to be. These recording heads are arranged so as to be located on the same horizontal line. For this reason, there is a problem that a space for accommodating the recording head in the width direction of the recording paper is required so that the recording head arranged on the side can print the end of the recording paper, and the size in the width direction is increased. .

[0003]

In order to solve such a problem, it is conceivable to arrange the recording heads in a direction perpendicular to the moving direction of the carriage. However, since the recording heads are arranged vertically, the recording heads are arranged in a horizontal direction. There is a problem that a water head difference occurs between the ink cartridges and the ink cartridges that are arranged, the ink supply pressure to each recording head varies, and the print quality deteriorates. The present invention has been made in view of such a problem, and an object of the present invention is to supply ink with uniform pressure to recording heads arranged in a vertical direction so that printing with high print quality can be performed. To provide a simple inkjet recording apparatus.

[0004]

In order to achieve the above object, in the present invention, a plurality of recording heads are arranged in a vertical direction with a difference in height, and ink is supplied to each recording head via an ink supply tube. In the ink jet recording apparatus for supplying ink, a valve mechanism that opens in response to a negative pressure generated by ink consumption of the recording head is connected between the recording head and an ink supply tube, and the valve mechanism is opened. The differential pressure at the time of the valve is set according to the height difference between the recording heads.

[0005]

The ink head is supplied with a uniform pressure to each print head by compensating for the head difference of each print head by a valve mechanism.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 shows an embodiment of an ink jet recording apparatus according to the present invention, in which a carriage 3 whose upper end and lower end are movably supported by guide members 1 and 2 has a plurality of members arranged in a vertical direction. , Three recording heads 4, 5, and 6 are arranged. Each of the recording heads 3 to 5 has a buffer tank 7, 8,
9 are connected to each other, so that ink consumed in printing is supplied from each of the buffer tanks 7 to 9.

The buffer tanks 7 to 9 are connected to a common ink cartridge 13 via ink supply tubes 10, 11, and 12, respectively. A platen 14 for supporting recording paper is disposed on the nozzle surfaces of the recording heads 4 to 6, and paper feed rollers 15 and 16 are provided above and below. Reference numeral 17 in the figure indicates a cartridge rack.

FIG. 2 shows an embodiment of the above-described buffer tank, taking one buffer tank 7 as an example, and an ink supply tube 10 is provided above a case 21 forming an ink storage chamber 20. Are provided, and an outlet 23 for supplying ink to the recording head 4 is formed below.

A valve mechanism 24 capable of adjusting the differential pressure is provided between the outlet 23 and the ink storage chamber 20. The valve mechanism 24 includes the spring 2 as shown in FIGS.
5, a valve body 27 which is constantly urged toward the ink storage chamber 20 and has a through hole 26 at the center thereof, and a valve seat 28 which seals the through hole 26 of the valve body 27. Is connected to the ink storage chamber 20 through the through hole 29 and the other surface is connected to the outlet 23 through the through hole 30.

By the way, as shown in FIG. 1, the recording heads 5 and 6 have height differences ΔH1 and ΔH2 in the vertical direction with respect to the uppermost recording head 4, respectively. The springs 25 of the connected buffer tanks 8 and 9 are set so that their elastic pressures are increased by an amount corresponding to the height differences ΔH1 and ΔH2.

In this embodiment, when the ink cartridge 13 is mounted, the ink supply tubes 10, 11, 1
The ink in the ink cartridge 13 flows into the buffer tanks 7, 8, and 9 via the air communication hole (not shown) formed in the ink cartridge 13 by the siphon phenomenon through the ink cartridge 13 through the ink cartridge 2. Among the buffer tanks, the ink in the ink storage chambers 20 of the buffer tanks 8 and 9 has a higher pressure than the ink in the ink storage chamber 20 of the buffer tank 7 by the height differences ΔH1 and ΔH2, respectively.

In this state, the recording head 5,
When the ink is consumed in 6, 7, the buffer tank 7,
Since the pressure at the outlets 23 of 8 and 9 decreases, the valve body 27 separates from the valve seat 28 against the urging force of the spring 25 as shown in FIG. Through hole 26
Flows into the recording heads 5, 6, 7.

Thus, the spring 2 of each buffer tank is
When the ink flows into the recording heads 5, 6, and 7 until the pressure equals to the differential pressure set by the valve 5, the valve bodies 27 of the buffer tanks 7, 8, and 9 lose the urging force of the spring 25 to the valve seat 28. The channel is closed and the flow path is closed.

As a result, the recording heads 6 and 7 can receive ink at the same pressure as the recording head 5 regardless of the height differences ΔH1 and ΔH2 from the recording head 5, respectively.

During the non-printing period, the valve bodies 27 of the buffer tanks 7, 8, 9 are moved by the urging force of the spring 25 to the valve seat 2
Since the flow path is closed by elastic contact with the ink cartridge 8, even if the ink cartridge 13 does not contain a porous material for absorbing ink, leakage of ink from the recording heads 5, 6, and 7 is prevented.

In the above-described embodiment, the valve mechanism for compensating for the head difference is incorporated in the buffer tank. However, it is apparent that the same operation can be obtained by providing only the valve mechanism.

Further, in the above-described embodiment, a plurality of buffer tanks 7, 8,
9, ink is supplied to the buffer tanks 7, 8, 9 as shown in FIG. 4 by using independent ink cartridges 30, 31, 32, respectively. Can also respond.

[0018]

As described above, according to the present invention, an ink jet recording apparatus in which a plurality of recording heads are arranged in a vertical direction with a difference in height, and ink is supplied to each recording head via an ink supply tube. , A valve mechanism that opens in response to a negative pressure generated by the consumption of ink in the recording head is connected between the recording head and the ink supply tube, and the differential pressure when the valve mechanism opens is changed by each recording head. The head difference is set in accordance with the height difference of each print head, so that the head difference of each print head can be compensated by a valve mechanism, and ink can be supplied to each print head at a uniform pressure. And printing with high printing quality is possible.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of an ink jet recording apparatus according to the present invention with respect to an ink supply system.

FIG. 2 is a sectional view showing one embodiment of a buffer tank used in the recording apparatus.

FIGS. 3A and 3B are enlarged views each showing a valve mechanism of the buffer tank according to the first embodiment; FIGS.

FIG. 4 is a view showing another embodiment of the ink jet recording apparatus of the present invention with respect to an ink supply system.

[Explanation of symbols]

 1, 2 Guide member 3 Carriage 4, 5, 6 Recording head 7, 8, 9 Buffer tank 10, 11, 12 Ink supply tube 13, 14, 15 Ink cartridge 20 Ink storage chamber 21 Case 22 Connection port 23 Outlet 24 Valve Mechanism 25 Spring 26 Through-hole 27 Valve body 28 Valve seat 29, 30 Through-hole

Claims (2)

[Claims] 1. An ink jet recording apparatus in which a plurality of recording heads are arranged in a vertical direction with a difference in height and supplies ink to each recording head via an ink supply tube. And a valve mechanism that opens in response to a negative pressure generated by ink consumption of the recording head, and a differential pressure when the valve mechanism is opened is set in accordance with a height difference between the recording heads. Inkjet recording device. 2. The ink jet recording apparatus according to claim 1, wherein the valve mechanism is incorporated in a buffer tank provided on a carriage on which the recording head is mounted.