JPH11138839A - Ink supply device - Google Patents

Abstract

(57) [Problem] To provide an ink supply device capable of reliably supplying ink without causing a problem of ink overflow or ink shortage due to excessive supply of ink from a main ink tank to a sub ink tank. . An upper portion of a plurality of ink chambers (22, 23, 24) in a sub ink tank (11) is communicated with each other by upper communication portions (28, 29).
Are provided with an atmosphere communication hole 32 and an ink sensor 33 for detecting the amount of ink. In the ink chamber 24, an ink discharge hole 11a for discharging ink to the print head is further formed. By detecting the amount of ink in the ink chamber 24 with the ink sensor 33, it is detected whether or not the supply of ink from the main ink tank to the sub tank 11 is necessary. Upper communication part 28, 2
Even if the ink film is stretched over 9 and the other ink chambers 22 and 23 become a closed space, the air communication state of the ink chamber 24 is ensured,
The ink amount can be detected without any trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink supply apparatus for supplying ink from a main ink tank to a print head via a sub ink tank having a plurality of ink chambers in an ink jet printing apparatus or the like.

[0002]

2. Description of the Related Art Conventionally, there is known an ink supply apparatus for supplying ink from a main ink tank to a sub-ink tank through an ink supply hole and supplying ink from the sub-ink tank to a print head through an ink discharge hole.

[0003] The sub-ink tank 1 considered by the present inventor earlier
Reference numeral 01 denotes a casing 102 having an upper opening and storing ink, as shown in FIG.
And a lid 103 for closing the upper opening of the upper communication part, and the inside thereof has an upper communication part 104, 1 that allows air to move upward.
05 to the lower communication hole 10 allowing the ink to move.
The ink is divided into first to third ink chambers 110, 111, 112 by partition walls 108, 109 provided with ink supply holes 101 a, and the ink supplied from the ink supply holes 101 a in the sub ink tank 101 is separated from each other. The air is separated from the ink by flowing in a meandering manner in the chambers 110 to 112, and only the ink moves to the print head side through the ink discharge hole 101b. Then, an ink sensor 11 for detecting an ink amount in the first ink chamber 110 is provided.
3 is provided, and the lid 103 facing the third ink chamber 112 is provided.
Is provided with an atmosphere communication hole 114 for opening the third ink chamber 112 to the atmosphere. When the ink sensor 113 detects that the ink has been reduced in the sub-tank 101 due to the ejection of the ink from the print head, a delivery unit such as a pump is driven to supply ink from a main ink tank (not shown). You.

This type of sub-ink tank supplies ink supplied from a main ink tank to a print head at a predetermined pressure. The positional relationship between the ink level in the sub-ink tank and the print head is determined by printing. It affects the pressure at the head and affects the print quality.

[0005]

In the sub ink tank 101 having such a plurality of ink chambers 110 to 112, when the sub ink tank 101 is transported or receives an impact,
The ink level of each ink chamber fluctuates, and the upper communication portion 10
4 and 105, the ink film may be formed on the upper communication portions 104 and 105 due to the surface tension of the ink during the passage. As described above, when the ink film is stretched in the upper communication sections 104 and 105, the ink chamber 1
10, 111 becomes a closed space. For example, when the ink chamber 110 in which the ink sensor 113 is provided becomes a closed space, there is no change in the liquid level in the ink chamber 110 regardless of the state of the ink in the other ink chambers. The ON or OFF state is maintained.

If the ink sensor 113 is OFF, it is determined that there is no ink, the pump is driven, and ink is supplied to the first ink chamber 110 through the ink supply hole 101a, but the ink chamber 110 is closed. The supply of ink from the main ink tank is continued because the ink level in the space hardly changes due to the supply of ink. As a result, ink flows into the second and third ink chambers 111 and 112 through the lower communication holes 106 and 107, and the ink supply becomes excessive, and the second and third ink chambers 111 and 11 are supplied.
2, the ink level may rise, and in some cases, ink may overflow to the outside through the atmosphere communication hole 114. On the other hand, if the ink sensor 113 is ON, it is determined that there is ink, and the first ink chamber 11
No ink is supplied to the print head 0, but since the first ink chamber 110 is a closed space, the ink level hardly changes even if ink is consumed by the supply of ink to the print head, and no ink is supplied. The state is maintained. As a result, the second and third ink chambers 11 are supplied without supplying ink.
Only the ink in the ink chambers 1 and 112 continues to be consumed, and the ink in the ink chambers 111 and 112 eventually runs out, and there is a possibility that the ink may not be supplied to the print head and the ink may be insufficient. Even if such extreme conditions do not occur, the liquid level in each ink chamber cannot be controlled, the pressure at the print head changes, and print quality is affected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an ink supply device capable of reliably supplying ink without causing a problem of ink overflow or ink shortage due to excessive supply of ink. With the goal.

[0008]

According to a first aspect of the present invention, there is provided an ink supply device for supplying ink to a print head from a main ink tank via a sub ink tank having a plurality of ink chambers, wherein the sub ink tank is A casing that stores ink, and a partition wall that partitions the inside of the casing to form a plurality of ink chambers. The partition wall has an upper communication portion that allows air to move at the top, and a movement of ink at the bottom. An air communication hole is provided for one of the ink chambers formed by the partition wall,
An ink amount detecting means is provided for the ink chamber in which the air communication hole is formed.

According to the first aspect of the present invention, since the air communication hole is formed in the ink chamber for detecting the ink, even if the ink film is formed in the upper communication portion, the ink is not consumed as the ink is consumed. Changes. Therefore, the state of ink consumption is detected by the ink amount detecting means, and the ink supply to the print head can be performed without causing ink overflow or ink shortage due to excessive ink supply, regardless of the state of other ink chambers. Done. In other words, in a state where the ink film is stretched on the upper communication portion, the ink chamber for detecting the ink functions as a single ink chamber,
Ink is supplied to the print head at a predetermined pressure.

According to a second aspect of the present invention, in the ink supply device of the first aspect, the upper communication portion is a communication hole.

According to the second aspect of the present invention, the upper communication portion is
Although it is a communication hole in which an ink film is easily formed, since an ink amount detecting means is provided for an ink chamber having an air communication hole, by detecting a change in the state of the ink in the ink chamber, it is possible to detect a change in the ink state. The consumption state is detected, and the ink is supplied to the print head without causing ink overflow or ink shortage due to excessive ink supply.

According to a third aspect of the present invention, in the ink supply device of the first or second aspect, an ink discharge hole for discharging ink to a print head is formed in the ink chamber in which the air communication hole is formed. .

According to the third aspect of the present invention, an air communication hole is provided in the ink chamber in which the ink discharge hole for discharging ink to the print head is formed, and the amount of ink in the ink chamber is detected. Regardless of the condition of other ink chambers,
A change in the ink liquid level in the ink chamber due to discharge from the ink discharge hole is ensured, and supply to the sub-ink tank can be controlled, so that ink is smoothly supplied to the print head.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a schematic configuration of an ink jet recording apparatus according to the present invention, and FIG. 2 is a longitudinal sectional view showing a sub ink tank of an ink supply device. In FIG. 1, in an inkjet recording apparatus 1, a carriage 3 on which a print head 2 is mounted is movably supported by guide rods 4 and guide bars 5 provided in parallel. A timing belt 8 is rotatably wound between a pair of pulleys 6 and 7, and a carriage 3 is attached and fixed to the timing belt 8 at an attachment portion 3a. When the timing belt 8 is rotated by a drive motor (not shown), the carriage 3 (print head 2) reciprocates in a print area where printing is performed on a recording medium.

The carriage 3 is provided with an ink storage section 9 for storing ink. The ink stored in the ink storage section 9 is distributed to a large number of discharge ports of the print head 2 and the ink is stored in the discharge ports. To print on a recording medium. The ink supply section 1 is provided in the ink storage section 9.
0 through the ink discharge hole 11a of the sub ink tank 11
And the ink supply hole 1 of the sub ink tank 11
1b is linked to a main ink tank (not shown) through another ink supply pipe 12. Therefore, the ink stored in the main ink tank is supplied from the main ink tank to the sub ink tank 11 through the ink supply pipe 12 and the ink supply hole 11b by a sending means (not shown) such as a pump. The ink is supplied from the ink tank 11 to the ink container 9 through the ink discharge hole 11 a and the ink supply pipe 10, and then the ink is finally supplied from the ink container 9 to the print head 2. The sub-ink tank 11 is installed at a stationary position outside the carriage 3 so that the liquid level of the ink inside the sub-ink tank 11 is lower than the discharge port of the print head 2. Pressure has been applied. Thus, the ink supply device 15 that supplies the ink to the print head 2 is configured.

A linear encoder 13 is provided along the running direction of the carriage 3 and has black vertical stripes formed on a transparent PET film, and a position of the carriage 3 is provided for each carriage 3 based on the linear encoder 13. A position detecting means is constituted by a photo sensor 14 (for example, a transmission type photo interrupter) for detecting the position, and the scanning amount of the carriage 3 is determined by counting the vertical stripes of the linear encoder 13 by the photo sensor 14. A control unit such as a microcomputer receives a signal from the position detection unit, and a print timing is generated based on the signal.
And controls the driving of the carriage 3 and the like.

As shown in detail in FIG. 2, the sub-ink tank 11 has a casing 21 having an upper opening for storing ink, and partitions the interior of the casing 21 from first to third ink chambers 22, 23, and 23. 24, and a lid 27 for closing an upper opening of the casing 21. The partition walls 25, 26 respectively move air upward. The first and second upper communication portions 28 and 29 (e.g., gaps) that allow ink are provided at the lower portion with first and second lower communication holes 30 and 31 that allow movement of ink. The lower communication holes 30, 31 and the ink discharge holes 11a of the partition walls 25, 26 are arranged so as not to be on the same straight line. Specifically, when viewed from a plane direction, the ink supply hole 11b and the ink discharge hole 11a
Is formed at a corner of the bottom wall of the casing 21, and the lower communication hole 30 is provided at an end of the partition wall 25 far from the ink supply hole 11 b,
Further, the lower communication hole 31 is provided in the ink discharge hole 11a of the partition wall 26.
The ink supplied from the ink supply hole 11b is formed at an end far from the sub-ink tank 11b.
Inside the ink chambers 22 to 24, the ink flows into the ink chambers 22 to 24, and is supplied to the print head 2 through the ink discharge holes 11 a. In addition, the both upper communication parts 28 and 29
Is formed so as to always be located above the liquid level in order to allow the flow of air between the ink chambers 22 to 24.

The ink chamber in which the ink supply hole 11a opens is the first ink chamber 22, the ink chamber in which the ink discharge hole 11b opens is the third ink chamber 24, and the ink chamber between the two ink chambers is the second ink chamber. The ink chamber 23 is provided. At a portion of the lid 27 facing the third ink chamber 24, an air communication hole 32 for opening the third ink chamber 24 to the atmosphere is provided, and an upper space of each of the ink chambers 22 to 24 is connected to the upper communication section 28. , 29
Through the atmosphere. At the same time, an ink sensor 33 is provided as an ink amount detecting means for detecting the amount of ink in the sub ink tank 11. The ink sensor 33 may be constituted by an electrode inserted into the ink chamber, or may be optical means provided externally to the ink chamber.

The ink sensor 33 is connected to a sending means such as a pump provided in the ink supply pipe 12 between the sub ink tank 11 and the main ink tank. When the ink sensor 33 detects that the ink has been reduced in the sub tank 11 due to the ejection of the ink by the print head, a sending unit such as a pump is driven,
Ink is supplied from a main tank (not shown).

According to the above configuration, since the third ink chamber 24 is provided with the atmosphere communication hole 32, the ink level reliably changes with the consumption of ink. Therefore, by providing the ink sensor 33 in the third ink chamber 24, the ink amount is reliably detected regardless of the state of the other ink chambers 22 and 23, and the main ink is detected based on the detection. Since ink is supplied from the ink tank to the sub-ink tank 11, the print head 2 can be supplied through the ink discharge hole 11a without causing a problem of ink overflow or ink shortage through the air communication hole 32.
Is reliably supplied to the ink.

That is, if the upper communicating portions 28 and 29 are in a state where the ink film is stretched, the first and second ink chambers 22 and 23 are closed spaces and the liquid level does not change. Since the third ink chamber 24 functions as a single ink chamber and the liquid level changes with the consumption of ink, the ink state of the third ink chamber 24 is detected by the ink sensor 33, and the ink is sent out by a pump or the like. By controlling the ink supply by the means, it is possible to avoid ink overflow or ink shortage due to excessive ink supply, and to always supply the ink to the print head at a predetermined pressure.

Further, the upper communicating portions 28 and 29 are
The ink sensor 33 is provided for the third ink chamber 24 having the air communication hole 32, even if the ink film is formed by a communication hole penetrating the upper ends of the ink communication holes 5 and 26. As described above, ink is reliably supplied to the print head 2 regardless of the presence or absence of the ink film.

In the above embodiment, the first and second
Three ink chambers 22, 23,
24, the present invention is not limited to this. For example, as shown in FIG.
At A, the inside of the casing 21A is divided into two ink chambers 22A,
The same applies to the case of partitioning into 23A,
In this case, the ink sensor 33 is provided so that a large amount of ink that can be supplied to the print head can be stored in the sub ink tank when the ink film is formed in the upper communication portion 28A and the ink chamber 22A becomes a closed space. It is desirable that the volume of one ink chamber 23A is larger than the volume of another ink chamber 22A.

[0025]

The present invention is embodied in the form described above, and has the following effects.

According to a first aspect of the present invention, a plurality of ink chambers in a sub-ink tank are connected to each other by an upper communicating portion, and an ink amount detecting means is provided for an ink chamber provided with an air communication hole. Therefore, even if an ink film is formed on the upper communication part and the other ink chamber becomes a closed space, the ink chamber for detecting the amount of ink maintains a state of communication with the atmosphere, and ink consumption is reduced. As a result, the liquid level changes, and the amount of ink can be accurately detected. Therefore, irrespective of the state of the other ink chambers, it is possible not only to prevent ink overflow and ink shortage due to excessive ink supply, but also to surely maintain the ink liquid level in the sub-ink tank at a predetermined value and print the ink. Can be supplied at a predetermined pressure.

According to the second aspect of the present invention, since the upper communication portion is a communication hole in which an ink film is easily formed, the ink amount detecting means is provided for the ink chamber having the air communication hole.
Irrespective of the state of other ink chambers, ink can be supplied to the print head without causing ink overflow or ink shortage due to excessive ink supply.

According to the third aspect of the present invention, an air communication hole is provided for an ink chamber having an ink discharge hole for discharging ink to a print head, and the amount of ink in the ink chamber is detected. Irrespective of the state of the ink chamber, it is possible to secure a change in the ink liquid level in the ink chamber due to the discharge from the ink discharge hole and control the supply to the sub ink tank, and to supply the ink to the print head. It can be done smoothly.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an ink jet recording apparatus according to the present invention.

FIG. 2 is a sectional view of a sub ink tank of the ink supply device according to the present invention.

FIG. 3 is a sectional view of a sub ink tank according to another embodiment.

FIG. 4 is a view similar to FIG. 2 for a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inkjet recording device 2 print head 9 ink storage section 11 sub ink tank 11a ink discharge hole 15 ink supply device 21 casing 22 first ink chamber 22A ink chamber 23 second ink chamber 23A ink chamber 24 third ink chamber 25 First partition wall 25A Partition wall 26 Second partition wall 28 Upper communication section 29 Upper communication section 30 Lower communication hole 31 Lower communication hole 32 Atmospheric communication hole 33 Ink sensor

Claims (3)

[Claims] 1. An ink supply device for supplying ink from a main ink tank to a print head via a sub ink tank having a plurality of ink chambers, wherein the sub ink tank has a casing for storing ink, and a casing inside the casing. A partition wall that forms a plurality of ink chambers, the partition wall includes an upper communication portion that allows air to move at an upper portion, and a lower communication portion that allows ink to move at a lower portion, Ink characterized in that an air communication hole is provided for one of the ink chambers formed by the partition walls, and an ink amount detecting means is provided for the ink chamber in which the air communication hole is formed. Feeding device. 2. The ink supply device according to claim 1, wherein the upper communication portion is a communication hole. 3. The ink supply device according to claim 1, wherein an ink discharge hole for discharging ink to a print head is formed in the ink chamber in which the air communication hole is formed.