JPS6255147A - Ink tank - Google Patents

Abstract

PURPOSE:To enable a fixed quantity of an ink to be constantly reserved in an ink tank irrespective of inclination of the tank, by providing an ink-supplying port, a level sensor and an air opening hole at a substantially central part of the tank. CONSTITUTION:Ink-supplying ports 18a, 19a are provided at a bottom part of a central part of the tank, the level sensor 9 is provided at a position corresponding to the ports, and an air opening hole 20a is provided at the center of an upper part of the tank. An inclined liquid surface produce the same effect on the ports 18a, 19a and on the level sensor 9, so that the ink can be securely supplied to the head side irrespective of the inclination of the ink tank. In addition, even when the ink containing bubbles enters the tank through circulation in an ink passage at the time of supplying the ink, the bubbles move from the liquid surface toward the hole 20a, so that no bubbles remain in the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink tank, and more particularly to an ink tank for temporarily storing ink used in an inkjet printer or the like.

[Prior Art] For example, the number of ink tanks used in color inkjet printers, etc., for temporarily storing ink provided between the head side and a removable ink cartridge is Multiple pieces are required depending on the ink.

Therefore, a plurality of ink tanks have to be arranged in a limited space, which inevitably results in an overall flattened structure.

On the other hand, the ink tank is equipped with an ink supply port, an atmosphere opening hole for keeping the pressure inside the tank constant, and a level sensor.

[Problems to be Solved by the Invention] However, in the past, the ink supply port, the atmosphere vent hole, and the level sensor were provided at appropriate positions in the ink tank.

However, if the ink tank is flat and the user does not necessarily place the ink tank in a horizontal position, the liquid level will be inclined, causing the following problem.

If the level sensor or ink supply port is located far away, or the ink tank is tilted, the level sensor may detect that there is a predetermined amount of ink, but the actual amount is less than the required amount. Or, ink may not be supplied to the head side.

Furthermore, if the air vent hole is located at an arbitrary position, air bubbles will be mixed into the ink.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention disposes the ink supply port in the center of the flat tank and at the bottom, and also provides a level sensor near the ink supply port. In addition, we adopted a structure in which the atmospheric vent is located in the center of the tank and located above.

[Function] When the above-mentioned structure is adopted, the ink supply port, level sensor, and atmosphere release hole are gathered at almost the center of the tank, so the level sensor and the ink supply port are aligned against the inclination of the ink tank. The conditions are the same, the level required for ink supply can be maintained without fail, and the incorporation of air bubbles into the ink can be avoided. [Example] The present invention will be described below based on the example shown in the drawings. Detailed explanation of.

Figure 1 and the following diagrams explain one embodiment of the present invention.
The figure shows an explanatory diagram of a flow path system to which an embodiment of the present invention is applied.

In the figure, the reference numeral 1 indicates a bubble jet 7J head element, and a plurality of head elements each having a large number of nozzles are arranged in the width direction of the recording paper.

Each head element 1 has two channels 2.3, one channel 2 being connected to a distributor channel 4 and the other channel 3 being connected to another distributor channel 5. .

One distributor flow path 4 is connected to a first ink tank 7 via a flow path 6, and a solenoid valve A is interposed in the middle of the flow path 6.

Further, the other distributor flow path 5 is connected to the first ink tank 7 via a flow path 8. A solenoid valve C and a pump P are interposed in the middle of the flow path 8. Pump P
is driven by a motor M capable of forward and reverse rotation, and can switch the ink supply direction.

A liquid level sensor 9 is attached to the first ink tank 7 and constantly monitors the ink level.

The first ink tank 7 can be opened to the atmosphere via a pipe 10 and a solenoid valve B interposed therebetween, so that the pressure inside the tank can be kept constant.

On the other hand, a detachable second ink tank 12 is connected in the middle of the flow path 8 and between the electromagnetic valve C and the pump P via a check valve 11.

Note that although the example shown in FIG. 3 is shown in a state corresponding to one color of ink, in the case of a multicolor printer, the above-mentioned flow path system is provided in multiple layers.

Further, a check valve 13 is provided in the flow path 8 connecting the head element and the pump side.

This check valve 13 has a structure that allows ink to pass only to the side.

Further, an overflow sensor 14 which also serves as a breather is provided at the end of the tube 10 on the side of the first ink tank 7 that is open to the atmosphere via the electromagnetic valve B.

On the other hand, the structure of the first ink tank 7 described above is shown in FIGS. 1 and 2.

This first ink tank 7 has a flat tank 15 and an arm 16.17 extending left and right from one side of the tank 15. As shown in FIG. 2, ink flow paths 18 and 19 and an air passage 20 are formed.

One ink flow path 18 corresponds to flow path 2 shown in FIG. 3, and the other ink flow path 19 corresponds to flow path 3.

One ends of the channels 18 and 19 are led to a central groove on the bottom of the tank 19, and are connected to channels 18a and 19 formed by penetrating the side of the tank.
It is connected to a.

The other end of each flow path 18, 19 is a supply port 18 on the arm 16.19 side.
b, connected to 19b.

Further, one end of the air passage 20 is connected to an atmosphere opening hole 2 formed above the central part of the tank 15 by penetrating the side wall of the tank.
0a, and the other end communicates with the overflow sensor 14 which also serves as the breather.

Further, the level sensor 9 is arranged at a position substantially corresponding to the supply ports 18a and 19a.

The ink tank as described above has the following mechanical parts.

That is, since the supply ports 18a and 19a are provided at the bottom of the central part of the tank, and the level sensor is also provided at a corresponding position, even if the ink tank is installed at an angle, the slanted liquid level will not be affected. has the same effect on the supply inlet and level sensor.

That is, when the liquid level on the supply ports 18a, 19a side becomes high, it is detected that ink remains above a predetermined level, and ink replenishment is not performed until the liquid level falls.

On the other hand, if the liquid level at the supply ports 18a, 19a is low, it is determined that the ink level in the tank is below a predetermined value, and the ink is supplied from the second ink tank 12.

Therefore, no matter how inclined the ink tank is, ink can be reliably supplied to the head side.

On the other hand, since the atmosphere opening hole 20a is formed at the center of the upper part of the tank, even if the ink containing air bubbles circulates in the ink flow path and enters the tank when the ink is fed by the pump, the air bubbles will be removed from the liquid. Since the ink flows from the surface toward the atmosphere opening hole 20a, no air bubbles remain in the ink.

Further, since the supply ports 18a and 19a are formed separately and separated by a predetermined distance, each supply port does not have an adverse effect on the other supply ports.

By the way, the operation in each mode of the Kashiji system shown in FIG. 3 will be explained with reference to Table 1.

(Margins below) Table 1 (C → Closed, 0 → Open) 1) Circulation mode This mode is used when supplying ink to each head 1 when the device is in standby state as described above, This mode is used to remove air bubbles in the head element or ink flow path and refresh the ink inside them at the same time.

In this state, all solenoid valves are open as shown in Table 1.

In this state, the pump P rotates in reverse, and the ink sucked from the first ink tank 7 passes through the flow path 8 via the solenoid valve C9 and the check valve 13, and passes through the distributor flow path 5. The ink is supplied to the head element l side through the flow path 3, and is pushed out from the nozzle, while also being supplied to the head element l side through the flow path 2. Distributor flow path 4
The ink flows back to the first ink tank 7 through a flow path 6 in which a solenoid valve A is interposed.

Due to this ink circulation, ink is supplied to the head element side, and air bubbles in the head and ink flow path are collected in the first ink tank 7. The air is guided to the overflow sensor 14 side, which also serves as a breather, through B, and is discharged to the outside from the air hole.

2) Print mode This mode is a mode in which the ink necessary for recording is supplied from the first ink tank 7 to the Helarad element l side. In this case, as shown in Table 1, all solenoid valves are opened and the pump is turned off. has stopped.

Since the inkjet printer in this example is an on-demand type, no pressure is applied to the ink during recording.
The pump is therefore not activated.

In this mode, negative pressure is applied to the head element side as ink is ejected from the distributor flow path 4. It is supplied to the head element 1 via the flow path 2, and recording is performed based on a recording command.

3) Supply mode This mode is a mode for supplying ink from the second ink tank 12 to the first ink tank 7, and is applied when the device starts to be used and when the amount of ink in the first ink tank 7 decreases. be done.

In this mode, all solenoid valves A-C are
is open and the pump is rotated forward.

Therefore, the ink from the second ink tank 12 is transferred to the check valve 11. The ink is supplied into the first ink tank 7 via the pump P, and the liquid level rises.

At this time, since the check valve 64 is interposed in series with the solenoid valve C, even if pressure is applied to the ink by the pump P, no circulation of the ink occurs.

Note that the cap 34 also rises at this time, and the absorbers 44 to
47 is in a state of being pressed against the head element l.

4) Pressure mode This mode applies pressure to the ink when the ink in the nozzle dries or when the nozzle becomes clogged, pushes the ink out of the nozzle, and removes the ink non-discharge condition. is in recovery mode.

In this case, as shown in Table 1, only A of the solenoid valves is closed, the others are open, and the pump is reversed.

At this time, the ink in the first ink tank 7 is pumped
, through the flow path 8 via the solenoid valve C1 check valve 64, and the distributor flow path 5. Head elm through channel 3)
Supplied to the l side.

At this time, since the solenoid valve A is closed, no ink circulation occurs and the ink is guided to the nozzle side of the head element, and the ink is ejected from the nozzle to remove the clogging.

In a flow path system that operates as described above, the ink tank of the present invention can exhibit excellent functionality.

[Effects] As is clear from the above description, according to the present invention, an ink supply port is provided below the center of the ink tank, a level sensor is provided close to this, and an air vent hole is provided in the ink tank. Since the structure is installed at the top of the central unit, the level sensor and supply port are equally affected by the tilt of the ink tank, and a constant amount of ink is always stored in the tank even if the tank is tilted. This enables reliable ink supply.

In addition, since the air release hole is provided at the top, air bubbles mixed in the ink can be reliably released to the atmosphere.

[Brief explanation of drawings]

The plan view of the tank and FIG. 3 are explanatory diagrams of the flow path system. 7...First ink tank 15...Tank 16.17...Arm 18.
19... Ink channels 18a, 19a---supply port

Claims (1)

[Claims] An ink tank characterized in that an ink supply port is provided at the lower center of the ink tank, a level sensor is provided near the supply port, and an atmosphere release port is provided above the central part of the ink tank.