JP2002273898A - Ink-jet recorder and method for supplying ink thereto - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recorder and a method for supplying ink thereto whereby good printing is realized and the whole of a sub tank can be made compact. SOLUTION: There are provided a recording head 6 for discharging ink drops correspondingly to printing data, a main tank for supplying ink to the recording head 6, and the sub tank 7 having upper and lower two tanks 7A and 7B connected to the main tank and the recording head 6 and communicating with each other. The upper tank 7A of the sub tank 7 is formed by an ink tank having an ink outlet 33 for leading out the ink to the recording head 6, and the lower tank 7B is formed by an ink tank which has an ink inlet 39 for leading in the ink from the main tank 9 by a pump pressure and which elastically deforms in accordance with a change of an internal pressure.

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 having two main and sub ink tanks (a main tank and a sub tank) for supplying ink to a recording head, and an ink supply method therefor.

[0002]

2. Description of the Related Art An ink jet recording apparatus is generally equipped with a recording head mounted on a carriage and moving in the width direction of the recording paper, and a paper for relatively moving the recording paper in a direction perpendicular to the moving direction of the recording head. Feeding means. In such an ink jet recording apparatus,
Printing on recording paper is performed by discharging ink droplets from a recording head based on print data. A recording head capable of discharging, for example, black, yellow, cyan, and magenta inks is mounted on the carriage, and not only text printing with black ink but also full-color printing is enabled by changing the discharge ratio of each ink. I have.

For this reason, an ink cartridge for supplying each ink to the recording head is provided in the apparatus main body.
In an ordinary ink jet recording apparatus, each ink cartridge storing the black, yellow, cyan and magenta inks is mounted on a carriage and moves together with the carriage. On the other hand, in a recording apparatus of this type provided for office use or business use, a large-capacity ink cartridge storing the above-described inks is arranged on a carriage in order to cope with a relatively large amount of printing. Instead, they are located on the device body side.

[0004] Further, the apparatus body side (cartridge holder)
There is also provided a recording apparatus of a type in which a main tank as an ink cartridge is disposed in the printer and a sub-tank is disposed on a carriage on which a recording head is mounted. Ink is supplied from each main tank to each sub tank via an ink supply tube, and ink is supplied from each sub tank to the recording head.

In such a printing apparatus, in order to improve throughput, ink is sequentially supplied from each main tank to each sub-tank while printing is performed, and ink is supplied from each sub-tank to a recording head. A function that can supply power stably is required.

As means for satisfying such a function, for example, an ink flow is generated from the main tank to the sub-tank by pressurizing the ink pack in the main tank with air, and the ink is supplied to the sub-tank. A configuration that enables replenishment is suitably employed. In addition, in each sub-tank mounted on the carriage, by adopting a configuration in which the amount of ink received from the main tank can be adjusted in accordance with the consumption of ink in the recording head, almost every sub-tank is almost always used. It is possible to store a certain amount of ink.

In recent printing apparatuses, the carriage is moved at a high speed in order to improve the printing speed. In such a printing apparatus, pressure fluctuation occurs in the ink inside the ink supply tube due to expansion and bending of the ink supply tube accompanying acceleration and deceleration of the carriage, and the ejection of ink droplets from the print head becomes unstable. For this reason, an open type ink supply system is adopted in which the sub-tank is opened to the atmosphere, the above-mentioned fluctuating pressure is released from the opening, and the ink stored in the sub-tank is supplied to the recording head by a difference in head.

[0008]

However, the fact that the ink supply system is of the open type has the following problems. That is, since the sub tank is open to the atmosphere,
When the ink is supplied, bubbles are included in the ink in the sub-tank, so that the degree of deaeration of the ink supplied to the recording head cannot be guaranteed, and good printing cannot be realized. In addition, since the supply of ink from the sub-tank to the recording head is performed by a difference in head of ink in the sub-tank, it is necessary to secure a sufficient height of the sub-tank, and there is a problem that the entire sub-tank becomes large. .

The present invention has been made to solve such a technical problem, and an ink jet recording apparatus capable of realizing good printing and reducing the size of the entire subtank. And an ink supply method therefor.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, an ink jet recording apparatus according to the present invention comprises a reciprocable carriage, and an ink droplet which is mounted on the carriage and ejects ink droplets in accordance with print data. A printhead, a main tank for supplying ink to the printhead, and a sub-tank connected to the main tank and the printhead and having two upper and lower tanks mounted on the carriage and communicating with each other. ,
The upper tank of the sub tank is formed by an ink tank having an ink outlet for leading ink to the recording head, and the lower tank has an ink inlet for introducing ink from the main tank, and has an elasticity according to a change in internal pressure. It is characterized by being formed by a deformable ink tank.

[0011] With this configuration, the ink in the main tank flows into the lower tank of the sub-tank by the pump pressure when the ink is supplied, and further flows from the lower tank to the upper tank. Supplied to the head. At this time, if a pressure fluctuation occurs in the lower tank (ink in the ink supply tube connecting the main tank and the sub tank), the lower tank is elastically deformed in accordance with a change in the internal pressure (volume), and this pressure (volume) )
Changes are absorbed.

Therefore, since the ink from the main tank can be supplied to the recording head by the closed ink supply system, the ink does not contain bubbles in the sub-tank at the time of supplying the ink as in the related art, and the degree of deaeration of the ink is reduced. And good printing can be realized. Further, since the supply of ink from the sub-tank to the recording head can be performed by the negative pressure generated on the recording head side, the height of the sub-tank can be reduced, and the size of the entire sub-tank can be reduced.

In this case, it is desirable that a part of the tank wall in the lower tank is made of an elastic film. With such a configuration, when a pressure fluctuation occurs in the lower tank, a part of the tank wall is elastically deformed in accordance with the pressure change in the lower tank.

The elastic film is made of a material having flexibility, ink resistance, and moisture / gas impermeability. With such a configuration, it is possible to obtain a sub-tank having an elastic film which is impermeable to moisture and gas and has excellent flexibility and ink resistance.

Further, it is preferable that a check valve that is opened by generating a negative pressure on the recording head side be disposed in the upper tank. With this configuration, a negative pressure is generated on the recording head side to open the check valve, and ink can be supplied from the main tank to the recording head via the sub tank.

It is desirable to have an ink amount detecting means for detecting the amount of ink in the sub-tank based on the amount of elastic deformation. With such a configuration, the amount of elastic deformation of the sub-tank is detected by the ink amount detecting means, and the amount of ink in the sub-tank is managed.

On the other hand, an ink supply method for an ink jet recording apparatus according to the present invention includes a reciprocable carriage, a recording head mounted on the carriage and discharging ink droplets corresponding to print data, and a pump mounted on the recording head. A main tank for supplying ink by pressure, and a sub-tank connected to the main tank and the recording head and having two upper and lower tanks mounted on the carriage and communicating with each other. A method of supplying ink from a main tank to a recording head, wherein, when supplying ink from the main tank to the recording head, the lower tank is elastically deformed according to a change in internal pressure.

According to this method, the ink from the main tank can be supplied to the recording head by a closed ink supply system, so that the ink does not contain air bubbles in the sub-tank during the ink supply as in the conventional case. In addition, it is possible to obtain an ink jet recording apparatus that realizes good printing by guaranteeing the degree of deaeration of ink. Further, since ink can be supplied from the sub-tank to the recording head by the negative pressure generated on the recording head side, the height of the sub-tank can be reduced, and the ink jet recording that can reduce the size of the entire sub-tank can be achieved. A device can also be obtained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus to which the present invention is applied and an ink supply method thereof will be described.
Description will be made based on the embodiment shown in the drawings. First, an ink jet recording apparatus will be described with reference to FIG. FIG. 1 is a plan view showing a basic configuration of an ink jet recording apparatus according to an embodiment of the present invention. A carriage denoted by reference numeral 1 in the figure is mounted on a timing belt 3 driven by a carriage motor 2. The guide member 4 guides the paper feed member 5 to reciprocate in the longitudinal direction, that is, in the main scanning direction, which is the width direction of the recording paper. Although not shown in FIG. 1, an ink jet recording head 6 (shown in FIG. 2) is mounted on the lower surface of the carriage 1 so as to face the paper feed member 5.

Further, sub-tanks 7a to 7d for supplying ink from a main tank (described later) to the recording head 6 are mounted on the carriage 1. These sub-tanks 7a to 7d are provided with four sub-tanks 7a to 7d corresponding to respective black, yellow, magenta and cyan inks in order to temporarily store the respective inks therein. Each ink is supplied from main tanks 9a to 9d as ink cartridges loaded into a cartridge holder 8 arranged in the apparatus main body via ink supply tubes 10, 10,... Made of a flexible material. Is configured.

Each of the main tanks 9a to 9d as the above-described ink cartridges has a flat outer shape. And the cartridge holder 8
Are arranged in a so-called vertical state so that the flat surfaces face the vertical plane, respectively.

On the other hand, in a non-printing area (home position) on the moving path of the carriage 1, a capping means 11 capable of sealing the nozzle forming surface of the recording head 6 is arranged. A cap member 11a made of a flexible material such as rubber capable of sealing the nozzle forming surface of the recording head 6 is disposed on the upper surface of the capping means 11. When the carriage 1 moves to the home position, the cap member 11a can seal the nozzle forming surface of the recording head 6.

The cap member 11a functions as a lid that seals the nozzle forming surface of the recording head 6 during the rest period of the recording apparatus and prevents drying of the nozzle openings. Although not shown in the drawing, one end of a tube of a suction pump (tube pump) is connected to the cap member 11a. The cleaning operation for sucking and discharging the ink from the nozzle 6 is performed. And the capping means 11
A wiping member 12 made of an elastic material such as rubber is disposed adjacent to the printing area side of the recording head 6 if necessary.
The nozzle forming surface can be wiped and cleaned.

Next, the ink supply system of the recording apparatus thus configured will be described with reference to FIGS. FIG. 2 is a cross-sectional view schematically showing the configuration of the ink supply system in the recording apparatus of FIG. 1. In FIG. 2, the same members as those of FIG. 1 are denoted by the same reference numerals, and detailed description is omitted. In FIG. 2, reference numeral 21 denotes an air pressurizing pump. The air pressurized by the air pressurizing pump 21 is supplied to a pressure regulating valve 22 and further supplied to a pressure detector 23.
The main tanks 9a to 9d (represented by a reference numeral 9 in FIG. 2) are supplied to the main tanks 9a to 9d, respectively.

The pressure regulating valve 22 is closed when the air pressure pressurized by the air pressurizing pump 21 reaches a predetermined value or more, and maintains the air pressure applied to each of the main tanks 9a to 9d within a predetermined range. It has a function to make it work.

The pressure detector 23 functions to detect the air pressure pressurized by the air pressurizing pump 21 and control the driving of the air pressurizing pump 21. That is, when detecting that the air pressure pressurized by the air pressurizing pump 21 has reached a predetermined pressure, the driving of the air pressurizing pump 21 is stopped. When the pressure detector 23 detects that the air pressure has become equal to or lower than the predetermined pressure, the air pressure pump 21 is driven. Therefore, the air pressure applied to each of the main tanks 9a to 9d by this repetition is maintained in a predetermined range.

As shown in FIG. 2, an ink pack 24 made of a flexible material filled with ink is provided in an outer case of the main tank 9 (ink cartridge).
Is stored. The space formed by the main tank 9 and the ink pack 24 constitutes a pressure chamber 25. In the pressure chamber 25, the space from the air pressure pump 21 via the pressure regulating valve 22 and the pressure detector 23 is provided. Is configured to be supplied.

With this configuration, each of the main tanks 9a
Each of the ink packs 24 accommodated in the main tanks 9a to 9d receives the pressure of the pressurized air.
Thus, an ink flow is generated at a predetermined pressure in each of the sub-tanks 7a to 7d.

The ink pressurized in the main tanks 9a to 9d is supplied to the ink supply valves 26 and 2 respectively.
, And the respective sub-tanks 7a to 7 mounted on the carriage 1 via the respective ink supply tubes 10, 10,.
d (represented by reference numeral 7 in FIG. 2).

Next, the sub-tank, which is a main part of the present invention, will be described with reference to FIGS. FIG.
FIG. 3D is a left side view, a front view, a cross-sectional view, and a right side view showing the sub tank of the ink jet recording apparatus according to the embodiment of the present invention. FIGS. 4A to 4C are plan views for explaining the operation of the ink amount detecting means for detecting the amount of ink in the sub tank shown in FIG. The sub-tank 7 shown in FIGS. 1 to 4 has two upper and lower tanks 7A and 7B which communicate with each other, and is connected to the main tank 9 via an ink supply tube 10.

The tank 7A comprises a box-shaped tank body 31 having a circular window 31a opened to the right and a flat circular tank wall 32 closing the circular window 31a of the tank body 31. It is arranged in a position above. The upper tank 7A is provided with an ink outlet port 33 for leading ink to the recording head 6, and a cylindrical ink chamber 34 communicating with the ink outlet port 33. The tank 7A is provided with a circulation port 35 located below the ink outlet port 33 and communicating with the ink chamber 34. And the tank 7A
A check valve 36 having a valve seat 50 protruding into the ink chamber 34 and generating a negative pressure on the recording head 6 side to be opened is disposed therein.

The check valve 36 has a planar circular valve element 51 (thin film) having a through hole 51a at the center and a resilient force in a direction such that the valve element 51 closes the through hole 51a. Is provided at all times. The valve element 51 is configured to be able to move in the direction of opening the through hole 51a (separating from the valve seat 50) against the elasticity of the compression coil spring 52 when the recording head 6 discharges ink. ing. The tank wall 32
Is formed by a plane circular rigid film having ink resistance and moisture / gas impermeability.

On the other hand, the tank 7B is provided with the circular window 31.
a, a box-shaped tank body 37 having a circular window 37a opened to the right side and a circular window 3 of the tank body 37
It consists of a flat circular tank wall 38 that closes 7a and is arranged below the tank 7A. In the lower tank 7B, an ink inlet 39 for introducing ink from the main tank 9 via the ink supply tube 10, and a cylindrical ink chamber 40 (a predetermined amount of ink is stored) communicating with the ink inlet 39. ) Is provided. The tank 7 </ b> B is provided with a circulation port 41 which is located above the ink introduction port 39 and communicates with the ink chamber 40. In the ink chamber 40, a filter (not shown) that captures dust and the like in the ink is provided in the circulation port 4.
1 are closed.

A first ink flow path 42 is provided at the center in the width direction of the left end face of each of the tanks 7A and 7B, and communicates with the flow ports 35 and 41 and extends in the vertical direction. In both the tanks 7A and 7B, there are provided second ink flow paths 43 which communicate with the ink outlet 33 and the recording head 6 and extend in the horizontal and vertical directions. The two ink flow paths 42, 43 have a part of the flow path wall formed of transparent plastic films 42a, 43a.
Is formed by

The tank wall 38 has flexibility, ink resistance and gas / moisture impermeability, and is formed of a flat circular thin film which is elastically deformed by a change in the internal pressure in the ink chamber 40. When the pressure in the ink in the ink supply tube 10 fluctuates, the tank wall 38 is elastically deformed by the pressure (volume) change in the tank 7B, and the pressure (volume) change is absorbed. I have.

At the front end of the right side of the tank 7B, a detection piece 44 extending in the horizontal direction through the center of the circle of the tank wall 38 is elastically held. As shown in FIGS. 4A to 4C, the detection piece 44 has a magnet holding portion 44a for holding a magnet 45 outside the sub-tank 7 and a deformation amount transmitting to the center of the tank wall 38. A portion 44b is provided. And
At the rear end of the left end surface of the tank 7B, a magnetoelectric conversion element 4 such as a Hall element corresponding to the magnet 45 is provided.
6 are arranged via element mounting pieces 47.

Thus, an ink amount detecting means for generating an electrical output by the magneto-electric conversion element 46 in accordance with the amount of magnetic force by the magnet 45 according to the amount of elastic deformation of the tank wall 38 is provided. Therefore, when the amount of ink in the sub tank 7 is reduced, the tank wall 38 is elastically deformed to the inside of the lower tank 7B as shown in FIG. (A), it is elastically deformed as shown in FIG. 7A, and the magnet 45 approaches the magnetoelectric conversion element 46. On the other hand, when the amount of ink in the sub tank 7 increases, the tank wall 38 elastically deforms to the outside of the lower tank 7B as shown in FIG. (C), the magnet 45 is elastically deformed as shown in FIG. For this reason, the magnet 45
The electric output of the magneto-electric conversion element 46 due to the movement of the sub-tank 7 can be detected as the amount of ink in the sub tank 7.

Next, an ink supply method (ink supply from the main tank to the recording head) of the ink jet recording apparatus according to the present embodiment will be described with reference to FIGS.
This will be described with reference to FIG. FIGS. 5 (a) and 5 (b)
FIG. 5 is a cross-sectional view for explaining the operation of the sub tank in the ink jet recording apparatus according to the embodiment of the present invention. First, in FIG. 2, when the ink pack 24 in the main tank 9 is pressurized by the air pressurizing pump 21,
When the ink in the ink pack 24 is
And flows into the lower tank 7B (ink chamber 40) of the sub tank 7 from the ink introduction port 39.

In this case, if the pressure in the ink in the ink supply tube 10 fluctuates, the tank wall 38 is elastically deformed in accordance with the fluctuating pressure, and the volume of the lower tank 7B changes. That is, when the pressure fluctuation of the ink is large, FIG.
As shown in (a), the tank wall 38 is elastically deformed to the side (outside) where the internal volume (pressure) of the ink chamber 40 is increased,
This change in volume (pressure) is absorbed. On the other hand, when the pressure fluctuation of the ink is small, as shown in FIG. 5B, the tank wall 38 reduces the inner volume of the ink chamber 40 (inside)
This volume change is absorbed. As a result, the pressure fluctuation generated in the ink in the ink supply tube 10 does not affect the ejection of the ink droplets from the recording head 6.

Next, when a negative pressure is generated to form a meniscus in the recording head 6, the check valve 36 is opened, and the ink in the ink chamber 40 flows from the circulation port 41 to the first ink flow path. 42, and the ink in the first ink flow path 42 flows from the circulation port 35 to the ink chamber 3 of the upper tank 7A.
4 flows into. Then, the ink in the ink chamber 34 passes through the through hole 51 a, flows from the ink outlet 33 into the second ink channel 43, and flows into the recording head 6 from the second ink channel 43. In this manner, ink is supplied from the main tank 9 to the recording head 6 via the ink supply tube 10 and the sub tank 7.

Therefore, in the present embodiment, since the ink can be supplied to the recording head 6 by a closed ink supply system, the ink does not contain air bubbles in the sub-tank 7 when the ink is supplied as in the related art, , It is possible to realize good printing by guaranteeing the degree of deaeration. Further, in the present embodiment, the supply of ink from the sub-tank 7 to the recording head 6 can be performed by the negative pressure generated on the recording head side, so that the height of the sub-tank 7 can be reduced, and the entire sub-tank can be reduced. Can be reduced in size.

In addition, in the present embodiment, ink from the main tank 9 is supplied to the sub-tank 7 by pump pressure, and ink from the sub-tank 7 is supplied to the recording head 6.
Is directly (not via a tube), it is not necessary to strictly consider the height position of the recording head 6 with respect to the main tank 9, so that the degree of freedom in component arrangement can be increased. Further, in the present embodiment, it is not necessary to strictly consider the height position of the recording head 6 because the restriction on the routing of the tube (ink supply tube) is reduced, and thus the outer dimensions of the tube (length and diameter). The degree of freedom in setting can also be increased. Further, in the present embodiment, the case where the detection of the ink amount is performed using the Hall element has been described, but the present invention is not limited to this, and may be performed using a position (distance) sensor or the like.

In this embodiment, the case where the ink is supplied from the main tank 9 to the sub tank 7 by the air pressurizing pump 21 outside the ink supply tube 10 has been described, but the present invention is not limited to this. Instead, it may be performed by a pump (not shown) arranged in the middle of the ink supply tube 10.

[0044]

As is apparent from the above description, according to the ink jet recording apparatus and the ink supply method thereof according to the present invention, good printing can be realized and the size of the entire subtank can be reduced. it can.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a basic configuration of an ink jet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an ink supply system from an ink cartridge to a recording head in the recording apparatus shown in FIG.

FIGS. 3A to 3D are left side views showing a sub-tank of the ink jet recording apparatus according to the embodiment of the present invention;
It is a front view, a sectional view, and a right side view.

FIGS. 4A to 4C are plan views illustrating an operation of an ink amount detecting unit for detecting an ink amount in a sub tank shown in FIG. 3;

FIGS. 5A and 5B are cross-sectional views illustrating an operation of a sub tank in the ink jet recording apparatus according to the embodiment of the present invention.

[Explanation of symbols]

1 Carriage 2 Carriage motor 3 Timing belt 4 Guide member 5 Paper feed member 6 Recording head 7 (7a, 7b, 7c, 7d) Sub tank 7A Upper tank 7B Lower tank 8 Cartridge holder 9 (9a, 9b, 9c, 9d) Main tank (Ink cartridge) 10 Ink supply tube 21 Air pressure pump 22 Pressure adjusting valve 23 Pressure detector 24 Ink pack 25 Pressure chamber 26 Ink supply valve 31 Tank body 31a Circular window 32 Tank wall 33 Ink outlet 34 Ink chamber 35 Flow port 36 Check Valve 37 Ink Body 37a Circular Window 38 Tank Wall 39 Ink Inlet 40 Ink Chamber 41 Flow Port 42 First Ink Flow Path 43 Second Ink Flow Path 44 Detecting Piece 44a Magnet Holder 44b Deformation Transmitter 45 Magnet 46 Magnetoelectric換素Ko 47 element attachment piece 51 the valve body 51a hole 52 a compression coil spring

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA15 EA23 EB17 EB21 EB34 EB53 EC18 EC32 EC64 FA10 KA08 KB05 KB09 KB27 KB35 KB37 KC14 KC24

Claims (6)

[Claims] 1. A reciprocable carriage, a recording head mounted on the carriage and ejecting ink droplets in accordance with print data, a main tank for supplying ink to the recording head, A sub-tank connected to the recording head and mounted on the carriage, and having two upper and lower tanks each communicating with each other; an upper tank of the sub-tank having an ink lead-out port for leading ink to the recording head. An ink tank formed by an ink tank, wherein the lower tank has an ink inlet for introducing ink from the main tank by a pump pressure, and is formed by an ink tank that is elastically deformed in response to a change in internal pressure. Expression recording device. 2. The ink jet recording apparatus according to claim 1, wherein a part of the tank wall in the lower tank is made of an elastic film. 3. The ink jet recording apparatus according to claim 2, wherein the elastic film is formed of a material having flexibility, ink resistance, and moisture / gas impermeability. 4. A check valve which is opened in the upper tank by generating a negative pressure on the recording head side, wherein the check valve is disposed in the upper tank.
An ink jet recording apparatus according to any one of the above. 5. An ink jet recording apparatus according to claim 1, further comprising an ink amount detecting means for detecting an amount of ink in said sub-tank based on an amount of elastic deformation thereof. 6. A reciprocable carriage, a printhead mounted on the carriage and ejecting ink droplets in accordance with print data, a main tank for supplying ink to the printhead, A sub-tank connected to the recording head, mounted on the carriage, and having two upper and lower tanks each communicating with each other, and supplying ink from the main tank to the recording head via the sub-tank. And supplying the ink from the main tank to the recording head by elastically deforming the lower tank in accordance with a change in internal pressure.