JP2000280493A - Ink-jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge all the ink in an ink circulation system with a simple configuration by discharging the ink stored in a reserve tank, and supply and discharge sub tanks via the discharge sub tank into a waste ink tank. SOLUTION: When an ink discharge command is inputted, a three direction changeover valve 71 is switched such that an ink discharge path 70 communicates with a drain path 72, and a circulating path communication valve 8, a sub tank communication valve 10 and an atmosphere communication valve 11 are closed. A tube pump 15 is driven so as to move the ink in a tube 25 to a sub tank C. Then, the valve 8 is opened so as to discharge the ink in the tank C to a waste ink tank 73 via a discharge path 70, and the pump 15. Moreover, the ink in a reserve tank A is discharged to the tank 73 via an ink returning path 6, the discharge path 70, the path 72, and the pump 15 successively. Furthermore, the ink in a sub tank B is discharged to the tank 73 via an ink going path 5, the tank A, the returning path 6, the tank C, the discharge path 70, and the pump 15.

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 an extra large capacity ink tank, and more particularly to an ink supply system having a supply sub-tank and a discharge sub-tank separate from a reserve tank mounted on a carriage. The present invention relates to an ink jet recording apparatus capable of easily discharging ink from a passage and an ink tank.

[0002]

2. Description of the Related Art Ink jet recording apparatuses have been applied to printers, fax machines, copiers and the like because of their advantages such as low noise, low running cost, easy downsizing and colorization. Recently, not only general-purpose inkjet printers for personal use, but also A1 version, A0
Ink jet recording has been used even in a plotter device that records a high-quality image of a photographic style on a large-sized sheet such as a plate. Furthermore, medical X-ray films and CT
Inkjet recording has also been applied to fields requiring high image quality and long-term storage stability, such as scanned images, which could only be expressed with silver halide photographic films.

By the way, in order to realize multi-gradation expression with high image quality similar to that of the silver halide photography system by an ink jet recording apparatus, it is necessary to increase the number of colors of ink used. For example, in a color plotter capable of photographic recording, inks of six or more colors are used, such as adding cyan, magenta, and other inks having a low color material density in addition to normal cyan, magenta, yellow, and black inks.

In such a field, since the ink jet recording apparatus is used for business use, a large amount of ink is used every day. However, when an extra large capacity ink tank is mounted on the carriage together with the recording head, the loading of the carriage is required. The weight becomes heavy and drive control of the carriage becomes difficult. On the other hand, if the ink tank capacity is reduced, the ink tank must be replaced frequently, which is inconvenient.

Therefore, in such an ink jet recording apparatus used for business use, a relatively small-capacity ink tank is arranged on the carriage, and a large-capacity ink tank is arranged outside the carriage. In many cases, ink pipes are connected between the tanks so that ink can be supplied from a tank outside the carriage to a tank on the carriage periodically or as needed.

FIG. 8 shows such an ink supply apparatus that the applicant has already filed. FIG. 8 shows only the ink supply system for one color.

In FIG. 8, a carriage 1 movably arranged with respect to the ink jet recording apparatus main body includes a recording head 2 having a plurality of ink ejection ports and a reserve tank A for storing ink to be supplied to the recording head 2. It is installed.

The apparatus main body is provided with a sub tank B, a sub tank C and a main tank D which are fixedly provided in the apparatus, in addition to a reserve tank A mounted on the carriage 1.

The sub-tank B is a tank for supplying ink to the reserve tank A, and is provided with an air communication port 3 at an upper portion thereof. The sub tank B and the reserve tank A are connected by an ink outward path 5. The sub tank C is a tank for storing the ink discharged from the reserve tank A, and the sub tank C and the reserve tank A are connected by the ink return path 6. The ink outward path 5 is a pipe for sending the ink stored in the sub tank B to the reserve tank A, and the ink return path 6 is a pipe for discharging the ink in the reserve tank A to the sub tank C. The ink return path 6 is provided with a valve 8.

The sub-tank B and the sub-tank C are connected by an ink flow path 9, and a valve 10 is provided in the ink flow path 9. An air communication path 12 having a valve 11 and an air chamber suction path 14 for sucking the air in the air chamber 13 of the sub tank C are provided above the sub tank C. The air chamber suction path 14 is formed of a flexible tube, and a tube pump 15 is provided in the middle thereof.

In the tube pump 15, a plurality of rollers 17 are arranged on a roller holder 16 in a circle.
The roller holder 16 is configured to be rotatable by a rotation shaft 18, and each roller 17 is also configured to be rotatable around each of a plurality of roller rotation shafts 19 supported by the roller holder 16.

The tube pump 15 further includes a pressing member 2
0 and a compression spring 21. That is, the pressing member 2 is opposed to the roller 17 with the tube 14 interposed therebetween.
0 is provided, and the pressing member 20 is urged toward the roller 17 by the compression spring 21 to crush the tube 14. When the roller holder 16 is rotated in the direction of the arrow E by a motor (not shown), the tube 14 is squeezed because the plurality of rollers 17 revolve. Thereby, the inside of the tube 14 becomes a negative pressure, and the atmosphere is sucked from the air chamber 13 of the sub tank C. The other end of the air chamber suction path 14 is guided to a waste ink tank 23.

The sub tank C is connected to a main tank D via an ink supply path 25, and ink is supplied from the main tank D. In the middle of the ink supply path 25, a check valve 27 that allows ink to flow only from the main tank D in one direction to the sub tank C is provided.
5 is provided with a tubular needle member 28 at the end on the main tank D side.

The main tank D has an ink suction pipe 3
4 and a tank sealing member 29 located at the end of the ink suction pipe 34 and functioning as an ink supply port. When the main tank D is loaded at a predetermined position in the apparatus, the needle member 28 is moved to the tank sealing member 2 of the main tank D.
9, the ink supply path 25 and the ink suction pipe 34 are connected via the tubular needle member 28.

The main tank D is provided with a tank sealing member 32 functioning as an air communication port. 3
Reference numeral 0 denotes an atmosphere communication passage provided in the apparatus, and a tubular needle member 31 is provided at the tip thereof. That is, as described above, when the main tank D is loaded at a predetermined position in the apparatus, the needle member 31 pierces the tank sealing member 32 of the main tank D and connects the inside of the main tank D to the atmosphere. I have.

The sub-tank B is provided with a maximum level sensor 40 for detecting an allowable maximum level of stored ink and a minimum level sensor 41 for detecting an allowable minimum level of ink to be stored. The sub tank C has a maximum level sensor 42 for detecting the maximum level of the stored ink.
Is provided.

Further, when the carriage 1 is located outside the recording area, for example, at a home position, the recording head 2
Is provided with a cap member 50 which functions to prevent clogging due to ink drying.
The cap member 50 is supported by a cap support member (not shown), and the cap support member includes a moving mechanism for bringing the cap member 50 into and out of contact with the recording head 2.

A tube 51 is connected to the cap member 50. The other end of the tube 51 is connected to an air chamber of the waste ink tank 23. The air chamber of the waste ink tank 23 has an air communication port 61 and is always at atmospheric pressure.

The tube 51 is provided with a suction pump 53. The suction pump 53 includes a holder 54, a rotating shaft 55
Arm 56 that pivots about the arm, and a pressure roller 57 provided at the tip of the arm 56.
As a result, it rotates in the direction of arrow F about the rotation shaft 55 and also rotates about the shaft 58. A pressing member 59 is provided to face the holder 54 with the tube 51 interposed therebetween. The pressing member 59 is moved by the compression spring 60 to the holder 5.
It is urged to the side 4 and squeezes the tube 51. To close the tube 51, the arm 56 is rotated to a position where the pressure roller 57 contacts the tube 51,
The arm 56 may be stopped at that position.

In the above apparatus, the ink pressure in the nozzles of the recording head 2 is determined by the height difference between the ink surface of the sub tank B and the nozzle surface of the recording head. In the sub-tank B, ink replenishment control is performed so that ink is between the highest level sensor 40 and the lowest level sensor 41, and ink is supplied to the reserve tank A on the carriage 1 via the sub-tank B. When the ink in the sub tank B runs out, the sub tank C is supplied with ink from the main tank D, and the sub tank B is supplied with ink by opening the valve 10 and leveling the sub tanks B and C. At the time of ink replenishment, the tube 51 is closed by the suction pump 53 and the cap member 50 is brought into contact with the recording surface of the recording head to prevent air bubbles from entering from the nozzles of the recording head 2.

[0021]

In the above-described ink jet recording apparatus, a large and heavy system including an ink supply system is used, and it is difficult to transport and move the apparatus with ink. Nevertheless, it does not have a function to drain all ink in the ink circulation system including the reserve tank A, the sub tanks B and C, the main tank D, and the ink path connecting these tanks, and to discharge the ink. Was.

Therefore, in the above-described ink jet recording apparatus, in order to discharge the ink once filled to the outside of the apparatus, the apparatus is almost completely disassembled, and each tank and the ink path are removed from the apparatus. Had to be discharged.

For this reason, in the above-mentioned apparatus, when the apparatus is transported or moved, or when the color or density of the ink in each tank is changed, the above-mentioned extremely troublesome work must be performed, which is complicated. It is.

The present invention has been made in view of such circumstances, and all ink in an ink circulation system having a subtank separate from a reserve tank mounted on a carriage can be easily discharged by adding a simple configuration. It is an object of the present invention to provide an ink jet recording apparatus capable of performing such operations.

[0025]

According to the first aspect of the present invention, there is provided a reserve tank mounted on a moving carriage for storing ink to be supplied to a recording head, a supply sub-tank for supplying ink to the reserve tank, A first ink path connecting the supply sub-tank and the reserve tank;
A discharge sub-tank for discharging ink from the reserve tank, a second ink path connecting the discharge sub-tank and the reserve tank, and a third ink path for moving ink between the supply and discharge sub-tanks. In the provided inkjet recording apparatus, a waste ink tank connected to the discharge sub-tank, the reserve tank,
An ink discharging means for discharging the ink stored in the supply and discharge sub-tank to the waste ink tank via the discharge sub-tank is provided.

The ink discharging means may be, for example,
As shown in the invention, a suction pump or the like is provided, and by driving the suction pump, all ink in the ink circulation system including a reserve tank, a supply and discharge sub-tank, and the like is discharged to a waste ink tank.

According to a third aspect of the present invention, in the first aspect of the present invention, a first valve provided in the second ink path, a second valve provided in the third ink path,
An atmosphere communication passage connected to the air chamber of the supply sub-tank,
A third valve provided in an air communication passage connected to the air chamber of the discharge sub-tank; and a gas suction passage connected to the air chamber of the discharge sub-tank, wherein the ink discharge means is provided in the discharge sub-tank. A fourth ink path for discharging ink, a flow path switching valve for selectively switching between the fourth ink path and the gas suction path to communicate with the ink discharge path to the waste ink tank, and an ink discharge path And the suction pump provided with the second and third valves closed and the first valve opened and the flow path switching valve connected to the fourth ink path side. A first control for driving and a second control for controlling the first and third valves to be closed and the second valve to be opened after a predetermined time has elapsed thereafter are performed. So that and a control means.

According to the third aspect of the present invention, by controlling the first control, the ink in the supply sub-tank is supplied to the first ink path, the reserve tank, the second ink path, the discharge sub-tank, and the fourth ink path. To the waste ink tank via the passage, the flow path switching valve, the suction pump, and the ink discharge passage.
In addition, the ink in the reserve tank is discharged to the waste ink tank via the second ink path, the discharge sub-tank, the fourth ink path, the flow path switching valve, the suction pump, and the ink discharge path, and the ink in the discharge sub-tank is discharged to the second ink path. 4 ink paths,
The ink is discharged to a waste ink tank via a flow path switching valve, a suction pump, and an ink discharge path. Further, by performing the second control, the ink in the third ink path connecting between the supply and discharge sub-tanks is discharged to the discharge sub-tank, the fourth ink path, the flow path switching valve, the suction pump, and the ink discharge path. Via the waste ink tank.

According to a fourth aspect of the present invention, in the third aspect of the invention, a detachable main tank for supplying ink to the discharge sub-tank and a fifth ink path connecting the main tank and the discharge sub-tank are further provided. And the control unit executes control for driving the suction pump with the first to third valves closed with the main tank removed before performing the first control. It is characterized by doing.

According to the fourth aspect of the present invention, there is further provided a main tank for supplying ink to the discharge sub-tank, and when the ink is discharged, the main tank is detached before performing the first control. Then, by performing control to drive the suction pump in a state where the first to third valves are closed and the flow path switching valve is connected to the fourth ink path side, the distance between the main tank and the discharge sub-tank is controlled. Is discharged to a waste ink tank via a discharge sub-tank, a fourth ink path, a flow path switching valve, a suction pump, and an ink discharge path.

According to a fifth aspect of the present invention, in the third or fourth aspect of the present invention, a cap member for capping the recording head and the waste ink tank or the second waste ink by sucking a cap space of the cap member. A second suction pump for discharging the liquid to a tank, wherein the control unit performs the second control, and then, in a state where the cap member is in contact with the recording head, the second suction pump. Is driven to discharge the remaining ink.

According to the fifth aspect of the present invention, the remaining ink is discharged via the recording head by driving the second suction pump in a state where the cap member is in contact with the recording head.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the waste ink tank is detachable, and the waste ink tank storing the discharged ink can be removed from the apparatus.

[0034]

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

FIG. 1 shows a simplified internal configuration of an ink supply system of an ink jet recording apparatus according to the present invention. The ink jet recording apparatus shown in FIG.
An ink ejection head of a type in which an electrothermal transducer as a heat energy source is provided corresponding to the ink ejection port and which drives the electrothermal transducer to cause film boiling in the ink to eject the ink. Showing things.

In FIG. 1, components that achieve the same functions as the components shown in FIG. 8 are denoted by the same reference numerals. FIG. 1 also shows only the ink circulating supply system for one color, and a plurality of such ink circulating supply systems are provided for performing color printing.

In FIG. 1, a recording head 2 having a plurality of ink discharge ports 4 and a reserve tank A for storing ink to be supplied to the recording head 2 are mounted on a carriage 1 which is movable relative to the ink jet recording apparatus main body. Is installed.

A cap member 50 which functions to prevent clogging due to ink drying or the like is provided at a position other than the recording area, for example, at a position facing the recording head 2 when the carriage 1 is at the home position. The cap member 50 is supported by a cap support member (not shown), and the cap support member includes a moving mechanism for bringing the cap member 50 into and out of contact with the recording head 2.

A tube 51 is connected to the cap member 50, and the other end of the tube 51 is connected to an air chamber of the waste ink tank 23. The air chamber of the waste ink tank 23 has an air communication port 61 and is always at atmospheric pressure. The reason why the cap member 50 is brought into the air communication state is as follows.
This is to prevent the ink filled in the nozzles of the recording head 2 from retreating from the ejection openings of the nozzles due to the air pressure inside the cap when the recording head 2 comes into contact with the recording head 2.

The tube 51 is provided with a suction pump 53. The suction pump 53 includes a holder 54, a rotating shaft 55
Arm 56 that pivots about the arm, and a pressure roller 57 provided at the tip of the arm 56.
As a result, it rotates in the direction of arrow F about the rotation shaft 55 and also rotates about the shaft 58. A pressing member 59 is provided to face the holder 54 with the tube 51 interposed therebetween. The pressing member 59 is moved by the compression spring 60 to the holder 5.
It is urged to the side 4 and squeezes the tube 51. To close the tube 51, the arm 56 is rotated to a position where the pressure roller 57 contacts the tube 51,
At that position, the arm 56 is stopped. Further, when performing a suction operation of ink or the like via the cap member 50, the arm 56 is continuously rotated in the F direction.

On the other hand, in addition to the reserve tank A mounted on the carriage 1, the apparatus main body is provided with a sub-tank B, a sub-tank C fixedly disposed in the apparatus, and a detachable main tank D. ing.

The sub-tank B is a tank for supplying ink to the reserve tank A, and has an air communication port 3 at its upper part. The sub-tank B and the reserve tank A are connected by an ink outward path 5 including a tube, a joint, and the like. The sub tank C is a tank for storing the ink discharged from the reserve tank A, and the sub tank C and the reserve tank A are connected by the ink return path 6. The ink forward path 5 is a pipe for sending the ink stored in the sub tank B to the reserve tank A, and the ink return path 6 is a pipe for returning the ink in the reserve tank A to the sub tank C. The ink return path 6 is provided with a circulation path communication valve 8 for opening and closing the return path 6.

The sub-tank B and the sub-tank C are connected by an ink flow path 9, and a sub-tank communication valve 10 for opening and closing the flow path 9 is provided in the middle of the ink flow path 9.
Is provided. The valve 10 may be a normal two-position switching valve that shuts off / communicates the ink flow in the ink flow path 9 or may be a sub-tank B to a sub-tank B
May be a check valve that allows the flow of ink only in the direction.

At the upper part of the sub tank C, an atmosphere communication valve 11 is provided.
And the air chamber 1 of the sub tank C
An air chamber suction passage 14 for sucking the air of No. 3 is provided. Both the atmosphere communication passage 12 and the air chamber suction passage 14 are made of a soft and flexible material, for example, a silicon tube. The atmosphere communication valve 11 is closed by crushing the atmosphere communication passage 12 with a cam member (not shown).
1 can be switched by opening and closing to open or close the air chamber 13 of the sub tank B to the atmosphere.

On the other hand, an ink discharge passage 70 is provided from the lower part of the sub tank C. This ink discharge path 70
Is connected to the input port of the three-way switching valve 71 together with the air chamber suction path 14, and the output port of the three-way switching valve 71 is connected to the waste ink tank 73 via the drain passage 72 and the tube pump 15. . Waste ink tank 7
Reference numeral 3 is configured to be detachable from the apparatus. The drain passage 72 is made of a flexible material such as a silicone tube.

The ink discharge path 70, the three-way switching valve 71, the waste ink tank 73, and the like are components of an ink supply system newly added according to the present invention.

The three-way switching valve 71 has a first position in which the ink discharge passage 70 communicates with the drain passage 72, a second position in which the air chamber suction passage 14 communicates with the drain passage 72, and a valve closing position. A valve switching operation based on the corresponding third position is performed. That is, the three-way switching valve 71 is commonly used for discharging ink through the ink discharging path 70 and for depressurizing the air chamber of the sub tank.

The tube pump 15 is provided in the middle of the drain passage 72. In the tube pump 15, a plurality of rollers 17 are arranged in a circle on a roller holder 16, the roller holder 16 is configured to be rotatable by a rotating shaft 18, and each roller 17 is also supported by the roller holder 16. Is configured to be rotatable around the roller rotation shaft 19. The tube pump 15 further has a pressing member 20 and a compression spring 21. That is, the pressing member 20 is provided so as to face the roller 17 with the tube 14 interposed therebetween.
Urged toward the roller 17 by the tube 14
Is crushing.

When the roller holder 16 is rotated in the direction of arrow E by a motor (not shown), the tube 72 is wrung because the plurality of rollers 17 revolve. As a result, the pressure inside the tube 72 becomes negative, and air or ink is sucked from the sub tank C. That is, when the three-way switching valve 711 is connected to the air chamber suction path 14, the tubes 14 and 72 become negative pressure by driving the tube pump 15, and if the atmosphere communication valve 11 is closed, the sub tank C The air in the air chamber is sucked and decompressed. In addition, the three-way switching valve 7
When 1 is connected to the ink discharge path 70 side, the inside of the tube 72 becomes negative pressure by driving of the tube pump 15, and the ink in the sub tank C is sucked through the ink discharge path 70.

The sub-tank C is connected to the ink supply path 25.
Is connected to the main tank D. A check valve 27 that allows ink to flow only from the main tank D in one direction to the sub-tank C is provided in the middle of the ink supply path 25, and a tubular needle member is provided at an end of the ink supply path 25 on the main tank D side. 28 are provided.

The main tank D has an ink suction pipe 3
4 and a tank sealing member 29 located at the end of the ink suction pipe 34 and functioning as an ink supply port. When the main tank D is loaded at a predetermined position in the apparatus, the needle member 28 is moved to the tank sealing member 2 of the main tank D.
9, the ink supply path 25 and the ink suction pipe 34 are connected via the tubular needle member 28.

The main tank D is provided with a tank sealing member 32 functioning as an air communication port. 3
Reference numeral 0 denotes an atmosphere communication passage provided in the apparatus, and a tubular needle member 31 is provided at the tip thereof. That is, as described above, when the main tank D is loaded at a predetermined position in the apparatus, the needle member 31 pierces the tank sealing member 32 of the main tank D and connects the inside of the main tank D to the atmosphere. I have.

The sub tank B is provided with a maximum level sensor 40 for detecting the maximum allowable level of the stored ink and a minimum level sensor 41 for detecting the minimum allowable level of the ink to be stored. The sub tank C has a maximum level sensor 42 for detecting the maximum level of the stored ink.
Is provided.

In the above technique, the ink pressure in the nozzles of the recording head 2 is determined by the height difference between the ink level of the sub tank B and the nozzle surface of the recording head, and these height differences are in the range of 20 to 100 mm. Is preferred.

FIG. 2 shows an example of the configuration of a control system for controlling the ink circulation supply system. Detection signals from the ink level sensors 40 to 42 are input to a controller 80, and the controller 80 The tube pump 15, the suction pump 53, the circulation path communication valve 8, the subtank communication valve 10, the atmosphere communication valve 11, the three-way switching valve 71, and the like are controlled in accordance with a command from a user or various device states. The following various operations are performed.

The operation of the ink circulation supply system performed by the controller 80 is mainly divided into: an initial ink filling operation; an ink circulation operation; an ink supply operation; an end operation; and a cleaning (ink discharge operation).

The initial ink filling operation is an operation of filling the ink circulation supply system with ink from a state where ink is not filled at all to a state where printing is possible.

The ink circulation operation means that the reserve tanks A,
This is performed to remove air bubbles in the ink circulation path including the sub tanks B and C, the ink outward path 5, the ink return path 6 and the ink flow path 9, and circulates ink between the sub tanks B and C and the reserve tank A. Let it.

The ink replenishment operation is an operation of replenishing ink from the main tank D to the sub tank B when the ink in the sub tank B is exhausted, more specifically, when the lowest level sensor 41 detects no ink other than the ink circulation operation. is there.

The terminating operation is an operation for ensuring the stability of the apparatus and smoothly performing the next startup when the apparatus is stopped.

The ink discharging operation relates to the present invention, and is an operation of draining all the ink in the ink circulating supply system and discharging the ink to the waste ink tank 73.

Hereinafter, each operation will be described.

(Initial Ink Filling Operation) First, the initial ink filling operation will be described with reference to FIG.

First, the user sets the main tank D filled with ink at a predetermined location in the apparatus. next,
When the power of the apparatus is turned on, the controller 80 detects the presence or absence of ink in the sub tank B based on the output of the lowest level sensor 41 provided in the sub tank B (step S1). Further, it was determined whether or not ink was present in the ink supply system based on the output of an ink detection sensor (not shown) provided at various points in the ink supply system, and it was determined that no ink was present in the ink supply system. In such a case, the following initial ink filling operation is performed. If it is determined in step S1 that there is ink in the sub tank B, the procedure is shifted to an ink circulation operation, which will be described later (step S2).

In the initial ink filling operation, first, the controller 80 sequentially closes the circulation path communication valve 8, the subtank communication valve 10, and the atmosphere communication valve 11 (step S).
3). Next, the driving of the tube pump 15 is started, and the air chamber 13 of the sub tank C is sucked and depressurized (step S).
4). When the pressure in the air chamber 13 of the sub tank C is reduced, the ink stored in the main tank D is injected into the sub tank C through the ink supply path 25. When the highest level sensor 42 in the sub tank C detects the completion of the ink filling (step S5), the air communication valve 11 is opened (step S6),
After returning the pressure in the sub tank C to atmospheric pressure, the tube pump 1
5 is stopped (step S7). The tube pump 15 is not necessarily stopped because the atmosphere communication valve 11 is open, but in this case, the tube pump 15 is stopped to reduce power consumption.

Next, the sub-tank communication valve 10 is opened (step S8). As a result, the ink is transferred from the sub tank C to the sub tank B, and the ink is leveled. Here, leveling means that the ink in the connected sub-tank C and sub-tank B does not move to any of the tanks or is in a state close to it.

The leveling time varies depending on the shapes of the sub-tank C and the sub-tank B, the pipe diameter of the ink flow path 9, the pipe diameter of the sub-tank communication valve 10, and the like. The leveling time is set in advance, and the apparatus waits for the set time from the time when the sub-tank communication valve 11 is opened. After this standby, the procedure from the next step 10 is performed (step S9).

A detection signal is output from the lowest level sensor 41 of the sub-tank B (step S10). When it is confirmed by leveling that the ink has been filled to the lower level sensor 41 of the sub-tank B or more, the sub-tank B
Is supplied to the reserve tank A and the procedure for filling the reserve tank A with the ink is executed.

That is, the circulation path communication valve 8 is opened, and the subtank communication valve 10 and the atmosphere communication valve 12 are sequentially closed (step S11).

Next, a capping operation of the recording head 2 is performed so that air bubbles do not enter from the nozzles of the recording head 2 (step S12). That is, after the cap member 50 is brought into contact with the recording head 2, the suction pump 53 is driven to crush the tube 51 with the pressure roller 57,
Is closed.

Next, the tube pump 15 is driven to
The air chamber 13 of the sub tank C is sucked (Step S1)
3). At this time, the three-way switching valve 71 connects the drain passage 72 to the air chamber suction passage 14. As a result, the ink in the sub tank B is sucked through the ink return path 6, the reserve tank A, and the ink forward path 5.

Accordingly, the ink in the sub-tank B is transferred to the reserve tank A via the ink forward path 5, and the ink in the reserve tank A is further transferred to the sub-tank C via the ink return path 6. As a result, all the tanks A, B, C
Is filled with ink.

The above-described ink transfer operation is performed by determining whether the lowest level sensor 41 of the sub tank B detects the absence of ink (step S14) or the highest level sensor 42 of the sub tank C detects the presence of ink (step S15).
Stop by

Then, after closing the circulation path communication valve 8, the atmosphere communication valve 11 is opened, and the sub tank C is returned to the atmospheric pressure (step S16). Next, the driving of the tube pump 15 is stopped (step S17). Further, the sub-tank communication valve 10 is opened (step S18), and waits for a predetermined time (step S19) to level the ink in the sub-tanks B and C described above.

As described above, the image can be printed (print standby state), and the initial ink filling operation is completed. The cap member 50 that has been in contact with the recording head 2 is separated from the recording head 2, and
3 is opened, and the tube 51 is opened to the atmosphere.

(Ink Circulation Operation) Next, the ink circulation operation will be described with reference to FIG.

In an ink supply system using a tube pipe as in the present apparatus, bubbles may be accumulated in the tube pipe due to a long period of time or the like, and an ink circulation operation is performed to remove the bubbles in the tube. The ink circulation operation includes: when the apparatus is turned on when the power of the apparatus is turned on, when the number of print dots exceeds a predetermined number, when the apparatus is left for a predetermined time or more, • This is performed when the number of carriage scans exceeds a predetermined number.

In the ink circulation operation, the ink is moved from the sub tank B to the sub tank C via the reserve tank A to the sub tank C, and the ink is circulated from the sub tank C to the sub tank B to perform the ink circulation operation. Remove any remaining air bubbles.

When any one of the above conditions is satisfied, an ink circulation operation is performed.
Of course, this is performed when there is ink in the sub tank B.

That is, when any of the above conditions is satisfied, the controller 80 determines whether or not there is ink in the sub tank B based on the output of the lowest level sensor 41 provided in the sub tank B (step S20). In this case, an ink supply operation described later is performed (step S2).
1) When ink is present, the following procedure is executed.

First, the controller 80 opens the circulation path communication valve 8 and sequentially closes the sub tank communication valve 10 and the atmosphere communication valve 11 (step S22). The recording head 2
The above-described capping operation is performed by the cap member 50 so that air bubbles do not enter from the nozzle.

Next, the operation of the tube pump 15 is started, and the air chamber 13 of the sub tank C is sucked and reduced in pressure (step S23). Thereby, the ink in the reserve tank A is transferred to the sub tank C through the ink return path 6. When the reserve tank A is depressurized by the above-described ink transfer, the ink is supplied from the sub tank B to the ink forward path 5.
Through the reservoir tank A.

When the lowest level sensor 41 of the sub tank B detects that there is no ink (step S24), or when the highest level sensor 42 of the sub tank C detects that there is ink (step S25), the circulation path communication valve 8 is closed. At the same time, the air communication valve 11 is opened (step S26),
After returning the pressure in the sub tank C to atmospheric pressure, the tube pump 1
5 is stopped (step S27).

Next, the sub-tank communication valve 10 is opened (step S28), and the process waits for a predetermined time (step S2).
9) The ink leveling of the sub tanks B and C described above is performed.

As described above, the image can be printed, and the ink circulation operation ends.

In the above-described ink circulation operation, air bubbles in the ink outward path 5 are particularly reduced by the air buffer 7 in the reserve tank A.
It is important to move to.

Because the negative pressure of the ink in the nozzles of the recording head 2 required for printing is determined by the height difference between the ink surface of the sub-tank B and the nozzle surface of the head 2, bubbles may enter between them. This is because it becomes a fluctuation factor of the negative pressure and greatly affects the image output.

When performing a printing operation after the ink circulation operation, it goes without saying that the cap member 50 is separated from the head 2.

(Ink Supply Operation) Next, the ink supply operation will be described with reference to FIG.

When the power is turned on, or at regular intervals during the operation of the apparatus, the lowest level sensor 41 provided in the sub tank B detects the presence or absence of ink in the sub tank B. The cycle of detecting the presence or absence of the ink is performed using a first timer (not shown). Then, when the minimum level sensor 41 detects that there is no ink at the time of detecting the predetermined time interval, the ink supply operation is performed (steps S30 to S32).

First, the circulation path communication valve 8, the sub-tank communication valve 10, and the atmosphere communication valve 11 are all closed (step S).
33). Next, the driving of the tube pump 15 is started (step S34), and the air chamber 13 of the sub tank C is sucked and depressurized. As a result, the ink in the main tank D is
7. The ink is injected into the sub tank C through the ink supply path 25.

Here, after resetting a second timer (not shown) for detecting the presence or absence of ink in the main tank D, the timer operation of the second timer is started (step S35).

Then, a predetermined time required for the ink replenishment operation is set in advance with a margin more than the standard time required for completing the ink replenishment operation, and the set time elapses after the second timer starts counting time. If the highest level sensor 42 in the sub-tank C detects ink before performing this operation (steps S36 and S37), it is determined that the ink supply operation to the sub-tank C has been completed, and the procedure of the next step S39 is executed. However, if the detection signal is not output from the highest level sensor 42 in the sub-tank C even after the predetermined set time has elapsed, it is determined that there is no ink in the main tank D, and that fact is displayed on the ink jet recording apparatus. The information is displayed on a panel or a computer connected to the recording device (steps S36 to S38).

In step S39, the atmosphere communication valve 1
1 is opened to return the inside of the sub tank C to the atmospheric pressure, and then the driving of the tube pump 15 is stopped (step S4).
0).

Next, the sub-tank communication valve 10 is opened (step S41) and waits for a predetermined time (step S42).
The above-described ink leveling of the sub tanks B and C is performed.

This ink supply operation may be performed during printing. This is because leveling changes the ink level of the sub tank B, but as long as the ink is between the highest level sensor 40 and the lowest level sensor 41, the ink level is changed by the level change of the ink level. This is because there is no effect.

Therefore, even if the ink in the sub tank B runs out during the printing, if the ink replenishing operation is performed, the ink will not run out during the printing as long as the main tank D has the ink.

If the volume from the bottom surface of the sub-tank B to the level surface of the lowest level sensor 41 is ensured so that the minimum amount of ink used per sheet can be ensured,
Even when the main tank D runs out of ink during printing and the sensor 41 of the sub-tank B detects the absence of ink, it is possible to prevent the sub-tank B from completely running out of ink. It is possible to prevent air bubbles from being mixed. Therefore, in the present ink circulating supply system, the ink can be replenished without particularly taking a supply time for replenishing the ink in each ink tank. Further, even during printing, it is not necessary to take a standby time for printing for replenishing ink, so that recording can be performed continuously and smoothly.

(End Operation) Next, an end operation will be described with reference to FIG.

When the end of the recording operation is selected (step S43), the circulation path communication valve 8 and the sub tank communication valve 1
0, the air communication valves 11 are sequentially opened (step S4).
4).

(Ink Discharge Operation) Next, an ink discharge (cleaning) operation, which is a main part of the present invention, will be described with reference to FIG.

The ink discharging operation is an operation for draining all the ink inside the ink circulation supply system and storing it in the waste ink tank 73 as described above.

This ink discharging operation is started only by a command from a user or an operator. Therefore, prior to performing this cleaning operation, the user removes the main tank D from the apparatus, and subsequently, the controller 80
Performs a predetermined operation for causing the printer to perform an ink discharging operation.

When such an ink discharge command is input, the controller 80 first switches the three-way switching valve 71 so that the ink discharge passage 70 is communicated with the drain passage 72 (step S46).

Next, the circulation path communication valve 8, the subtank communication valve 10, and the atmosphere communication valve 11 are closed (step S).
47). Next, the tube pump 15 is driven (step S48). As a result, first, the ink in the tube 25 connecting the sub tank C and the main tank D is transferred to the sub tank C. The controller 80 waits for a predetermined time set for the time required for the ink transfer (step S49), and then returns to the circulation path communication valve 8
Open. Sub tank communication valve 10 and atmosphere communication valve 1
1 remains closed (step S50).

As a result, the ink in the sub tank C is supplied to the ink discharge passage 70, the three-way switching valve 71 and the drain passage 7
2. Waste ink tank 73 via tube pump 15
Is discharged to The ink in the reservoir tank A is
Ink return path 6, sub tank C, ink discharge path 70, three-way switching valve 71 and drain path 72, tube pump 1
5 are sequentially discharged to the waste ink tank 73. Further, the ink in the sub-tank B passes through the ink forward path 5, the reserve tank A, the ink return path 6, the sub-tank C, the ink discharge path 70, the three-way switching valve 71, the drain path 72, and the tube pump 15 in that order, It is discharged to 73.

As described above, the ink in the sub tank B, the reserve tank A, and the sub tank C is sequentially discharged to the waste ink tank 73.

Thereafter, after waiting for a predetermined time sufficient for all the ink circulation supply systems including the sub-tank B, the reserve tank A and the sub-tank C, the ink forward path 5 and the ink return path 6 to be depleted of ink ( Next, the circulation path communication valve 8 is closed and the sub tank communication valve 10 is opened (step S5).
2). The atmosphere communication valve 11 is kept closed.

Thus, the sub-tank communication passage 9
The ink remaining in the sub-tank C and the ink discharge path 7
The waste ink is discharged to the waste ink tank 73 via the 0, 3-way switching valve 71, the drain passage 72, and the tube pump 15.

Thereafter, after waiting for a predetermined time sufficient for the ink in the sub-tank communication passage 9 to be exhausted (step S53), the driving of the tube pump 15 is stopped (step S54). Then, the three-way switching valve 71 is switched to the normal position, that is, the position where the drain passage 72 communicates with the air chamber suction passage 14 (step S55).

Finally, after the cap member 50 is brought into contact with the recording surface of the recording head 2, the suction pump 53 is driven to suction ink remaining in the reserve tank A and the nozzle portion of the recording head 2. And discharged to the waste ink tank 23.

By the above operation, all the ink in the ink circulation supply system could be discharged to the waste ink tanks 73 and 23.

The waste ink tank 73 is detachable, and if the waste ink tank 73 is removed from the apparatus after the above-described ink discharging operation, the ink is completely removed from the apparatus. Thus, it is possible to carry out transportation or transfer while the apparatus is reduced in weight and without causing ink leakage or the like. In addition, refilling with inks having different colors or densities can be easily performed.

In the embodiment, the waste ink tank 23
And 73 are separate, but they may be shared.

As the form of the suction pumps 15, 53, any other pump form may be used.

[0116]

As explained above, according to the present invention,
Since the ink supply device includes an ink discharge unit that discharges the ink stored in the reserve tank and the supply and discharge sub-tank to the waste ink tank via the discharge sub-tank, it includes a reserve tank, a supply and discharge sub-tank, and the like. All the ink in the ink circulation system can be easily discharged to the waste ink tank without causing ink leakage, and the color and density of the ink in the tank during transportation or transfer of the apparatus or in each tank can be adjusted. It can be easily dealt with when making changes. In addition, if the flow path switching valve is used for both the suction of the air chamber of the discharge sub-tank and the suction of the ink, the cost of the apparatus can be greatly reduced and the apparatus can be downsized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of an ink circulation system of an ink jet recording apparatus according to the present invention.

FIG. 2 is a block diagram illustrating an example of an internal configuration of a control system according to the embodiment of FIG. 1;

FIG. 3 is a flowchart showing a procedure of an initial ink filling operation in the embodiment of the present invention.

FIG. 4 is a flowchart illustrating a procedure of an ink circulation operation in the embodiment of the present invention.

FIG. 5 is a flowchart illustrating a procedure of an ink supply operation in the embodiment of the present invention.

FIG. 6 is a flowchart showing a procedure of an end operation in the embodiment of the present invention.

FIG. 7 is a flowchart illustrating a procedure of an ink discharging operation in the embodiment of the present invention.

FIG. 8 is a diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 2 Recording head 3 Atmospheric communication path 4 Ink discharge port 5 Ink outward path 6 Ink return path 7 Air buffer 8 Circulation path communication valve 9 Ink flow path 10 Subtank communication valve 11 Atmospheric communication valve 12 Atmospheric communication path 13 Air chamber 14 Air chamber suction Path 15 Tube pump 23 Waste ink tank 25 Ink supply path 27 Check valve 28 Needle member 30 Atmospheric communication path 30 31 Needle member 40 Maximum level sensor 41 Minimum level sensor 42 Maximum level sensor 50 Cap member 53 Suction pump 70 Ink discharge path 71 3-way switching valve 72 Drain passage 73 Waste ink tank 80 Controller A Reserve tank B Sub tank C Sub tank D Main tank

Continued on front page F-term (reference) 2C056 EA22 EA23 EA24 EA27 EB02 EB21 EB50 EC02 EC03 EC18 EC20 EC28 EC49 EC62 EC64 FA03 FA10 JA13 JC05 JC08 JC13 KB04 KB09 KB16 KB37 KC02 KC16 2C057 AF99 AG80 AL02 AL03 AM40 AM02

Claims (7)

[Claims] A reserve tank mounted on a moving carriage for storing ink to be supplied to a printhead;
A supply sub-tank for supplying ink to the reserve tank, a first ink path connecting the supply sub-tank and the reserve tank, a discharge sub-tank for discharging ink from the reserve tank, and connecting the discharge sub-tank to the reserve tank An ink jet recording apparatus comprising: a second ink path for supplying ink and a third ink path for moving ink between the supply and discharge sub-tanks; a waste ink tank connected to the discharge sub-tank; and the reserve tank. And an ink discharging means for discharging the ink stored in the supply and discharge sub-tank to the waste ink tank via the discharging sub-tank. 2. The ink discharge means includes a suction pump provided between the discharge sub-tank and the waste ink tank, and the suction pump pumps the ink stored in the reserve tank, the supply and discharge sub-tank to the discharge sub-tank. 2. The ink jet recording apparatus according to claim 1, wherein the ink is discharged to the waste ink tank via a printer. A first valve provided in the second ink path; a second valve provided in the third ink path; an atmosphere communication path connected to an air chamber of the supply sub-tank; A third valve provided in an atmosphere communication path connected to the air chamber of the discharge sub-tank; and a gas suction path connected to the air chamber of the discharge sub-tank, A fourth ink path for discharging the ink, a flow path switching valve for selectively switching between the fourth ink path and the gas suction path and communicating with the ink discharge path to the waste ink tank, A suction pump provided in the middle of the path, and a state in which the second and third valves are closed, the first valve is opened, and the flow path switching valve is connected to the fourth ink path side. A first control for driving the suction pump and a second control for controlling the first and third valves to be closed and the second valve to be opened after a predetermined time has elapsed thereafter. The inkjet recording apparatus according to claim 1, further comprising: control means for performing. 4. A detachable main tank for supplying ink to the discharge sub-tank, and a fifth connecting the main tank and the discharge sub-tank.
And the control means, before performing the first control, closes the first to third valves and switches the flow path in a state where the main tank is removed. 4. The ink jet recording apparatus according to claim 3, wherein the control for driving the suction pump is performed with a valve connected to the fourth ink path side. 5. A cap member for capping the recording head, and a second suction pump for sucking a cap space of the cap member and discharging the cap space to the waste ink tank or the second waste ink tank. After performing the second control, the control unit drives the second suction pump to discharge the remaining ink while the cap member is in contact with the recording head. The inkjet recording apparatus according to claim 3. 6. The ink jet recording apparatus according to claim 1, wherein the waste ink tank is detachable. 7. The recording head according to claim 1, further comprising an electrothermal transducer for generating heat energy for causing film boiling of the ink, as an element for generating energy used for discharging the ink. Item 7. An ink jet recording apparatus according to any one of Items 1 to 6.