JPS5945160A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To discharge air bubbles and solids in a recording head, together with ink, during non-recording period by raising the pressure of gas inside a cartridge box in which a bag storing a recording ink is housed. CONSTITUTION:A cartridge box 6 in which an ink-stored bag 5 is housed is of an enclosed structure other than an air hole 7, and the inside of the box 6 is led through the air hole 7 to the open air usually. A connecting means 14 is fixedly provided on the outside of the air hole 7 under a condition that the ink cartridge is rightly attached to the connector 9 of the recorder body. One end of a hollow movable shaft 15 is connected to an air pump 16 for pressurization. An elastic pressing part 17 is attached to the other end of the movable shaft, and the connecting means 14 is of a solenoid type. When being electrified, the movable shaft 15 is moved vertically. An air path through which compressed air sent through a tube 18 from the air pump 16 is flowed is formed. The air pump 16 and the connecting means 14 are turned on during non-recording period and air bubbles and solids in the ink path can thus be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink sheet recording apparatus, and more particularly to the removal of air bubbles in an ink flow path from an ink tank to a recording end.

An inkjet recording device jets ink as small droplets from a narrow nozzle to record characters, figures, etc. on a recording surface as dots. In this case, in order to draw high-quality characters, figures, etc., fine ink droplets of equal diameter must be ejected regularly and intermittently. In order for these ink droplets to fly smoothly and to stably draw characters, figures, etc. on recording paper, the properties of the ink itself must be sufficiently uniform and stable. It is necessary to prevent air bubbles from entering the ink flow path from the ink tank to the recording head.

In addition, drying of the ink in the nozzle, dust, paper dust, etc. can cause solidified matter in the ink, which often causes clogging. This may cause ink non-ejection or unstable ejection, and the ejection accuracy such as ejection efficiency, stability of ink droplet formation, and responsiveness may deteriorate, so it is necessary to remove these impurities as described above.

As mentioned above, in the inkjet recording device values,
1' It is an essential condition to completely remove air bubbles and solid matter generated or mixed in the ink flow path.

Conventional methods have been used when air bubbles or foreign matter have entered the nozzle in the recording head or the ink flow path of the flo.

(1) A method in which the ink tank is locally pressed to increase the ink pressure, and air bubbles, foreign matter, etc. are discharged together with the ink from the nozzle at the end of the ink flow path.

(2) A pressurized chamber is provided in the middle of the ink supply system that fluidly connects the ink tank and the recording head, and the ink is sent to the nozzle side by increasing the ink feed amount and ink pressure using an electric pump, etc., to remove air bubbles and foreign objects from the nozzle. How to learn about things like this.

(Japanese Unexamined Patent Publication No. 55-53570, etc.) (3) A method in which a cap is placed close to the nozzle surface and ink is sucked out from the nozzle using a suction pump to remove air bubbles and foreign objects. (Japanese Unexamined Patent Publication No. 56-113464) However, each of the above-mentioned methods for removing (purging) air bubbles and foreign matter has the following drawbacks, which poses a practical problem.

(1) Mechanical pressing means lacks pressure accuracy and stability,
In particular, it is difficult to apply constant pressure regardless of the remaining amount of ink.

The pump pressurizing means (2) requires an expensive liquid pump, which poses a cost problem.

(3) The suction means from the nozzle surface is complicated and expensive, and requires high precision due to the relative relationship between the suction speed and the ink supply speed.

As described above, all conventional purging means are still inadequate in terms of structure, cost, and stability.

- In an inkjet recording apparatus, a sealed ink cartridge is usually used as an ink supply device for supplying ink to a recording head in order to keep the ink in a stable state without exposing it to the outside air. In this ink cartridge, ink is filled in a highly airtight bag or container to prevent air from entering. This ink cartridge cartridge is removably attached to the cartridge receiver so that new ink can be replenished by replacing the ink cartridge.

The present invention has been made for the purpose of removing air bubbles and solid matter in the ink flow path using the above-mentioned replaceable ink cartridge system. The present invention provides an inkjet recording device capable of recovering from such troubles, and the present invention makes it possible to provide a highly accurate and stable purge device at a low cost with a means that has a simple structure and operates reliably compared to conventional methods. .

The features of the purge device for an inkjet recording apparatus according to the present invention are as follows.

[a) Regardless of the amount of ink remaining in the ink storage bag, ink can always be pumped at a constant pressure.

(b) It is easy to switch between ink supply using hydrostatic pressure during recording and pressurized supply from the purge reservoir during non-recording.

(cl) The ink inside the ink cartridge can be evenly pressurized.

(d) Since no excessive force is applied to any part of the ink storage bag, there is no chance of the ink storage bag being destroyed.

(e) The structure is simple and the operation is reliable.

) Cost can be reduced.

The present invention will be specifically described below with reference to the drawings.

FIG. 1 shows an outline of an inkjet recording apparatus of the present invention. In the figure, the recording head includes a plurality of nozzles 1 that eject ink droplets, a plurality of pressure chambers 2 that communicate with the nozzles 1, a common ink chamber 3 that distributes and supplies ink to each of the pressure chambers 2, and a common ink chamber 3 that distributes and supplies ink to each pressure chamber 2. and artificial means 4 for introducing ink from an ink cartridge into the chamber 3. Recording ink is filled in a highly airtight ink storage bag 5 made of a flexible material in a sealed state to prevent air from entering, and is housed in a cartridge housing 6.

Ink car) IJ is a nearly airtight cart with air holes 7 perforated at one end! '16 and this housing 6
The ink storage bag 5 is housed inside the ink storage bag 5, and the mouthpiece 8 is made of an elastic member or the like and is provided at the other end of the housing 6 to make the ink storage bag 5 liquid-tight. The mouthpiece 8 of the ink cartridge can be attached to and detached from a connector 9 fixed to a part of the recording apparatus. One end of the ink supply pipe 10 is connected to the connector 9, and the other end is connected to the recording inlet means 4 via a filter 11.

The ink storage bag 5 housed inside the cartridge/Fuji casing 6 made of a solid outer wall is made of, for example, polyethylene, polypropylene, vinyl chloride, vinylidene chloride,
It is made of a single layer of flexible film material such as polyester or nylon, or a laminate of these materials. Further, the cap portion 8 and the connector 9 allow ink in the cartridge to flow into the ink supply tube by penetrating the elastic backing member with a thin tube built into either of them.

In the ink supply system configured as described above, by artificially connecting the ink cartridge to the connector 9, the ink in the ink storage bag is fluidly connected to the mouthpiece 8 and the connector 9, and a more flexible ink supply tube [ 0
is supplied into the recording head from the recording head's artificial means 4 via the filter 1j. The ink that has not been supplied to the recording head first enters the common ink chamber 3, from where it is further recorded as a dot matrix). It is branched into a pressure chamber 2. In this way, the area inward from the nozzle 1 is filled with ink from the ink cartridge.

The ink liquid level in the ink cartridge is maintained lower than the nozzle 1, and the hydrostatic pressure of the ink on the nozzle surface,
Since an ink meniscus is formed due to the surface tension of the ink and maintains an equilibrium state, there is no risk of ink leaking from the nozzle 1 during non-recording.

On the other hand, a part of the wall of the pressure chamber 2 is a flexible wall, and a piezoelectric transducer 12 electrically connected to an m-pulse generator 13 is adhered to the outer surface of the wall. The piezoelectric transducer 12μ is a suitable flexible plate that can bend toward the inside of the pressure chamber 2 when receiving an electric signal from the pulse generator 13, and is made of, for example, a piezoelectric crystal, and is made of a conductive thin film. It is glued to the outer wall of the pressure chamber.

In the inkjet recording device having the above configuration,
The piezoelectric transducer 12 is suddenly deflected inward by the electrical signal from the electronic pulse generator 13, and the resulting rapid decrease in the volume of the pressure chamber 2 causes the ink inside to be ejected from the nozzle 1 as ink droplets and fly. Then, the dots reach the recording paper that is moving relatively to the opposite side to record a dot image.

Next, the ink cartridge pressurizing device according to the present invention will be explained with reference to FIG. The cartridge housing 6 that houses the ink storage bag 5 has a sealed structure except for the air holes 7, and the inside of the cartridge housing normally communicates with outside air through the air holes 7 as shown in the figure. . When the ink cartridge cartridge is still properly attached to the connector 9 of the recording device, a connecting means 14 is fixedly installed outside the air hole 7, and a hollow movable shaft 1 of the connecting means 14 is fixedly connected to the air hole 7.
One end of 5 is connected to a pressurizing air pump 16. An elastic pressure contact member (for example, an OIJ song 17) is attached to the other end of the movable shaft.The connecting means 14 is, for example, an electromagnetic solenoid, and when a current is connected to a built-in coil, it is made of an iron core. Movable shaft 15 moves up and down. Movable shaft 1
5 is hollow and forms an air flow path through which compressed air sent from the processing air pump 16 via the tube 18 flows and reaches the other end.

When the purge is required during non-recording, the solenoid of the connecting means 14 is turned ON by an automatic or manual switch, and the movable shaft 15 is pushed down to the cartridge housing 6 via the pressure contact member 17. Close to. As a result, an air-tight air flow path from the air pump 16 to the cartridge housing 6 via the tube 18, the movable shaft 15, the pressure member 17, and the air hole 7 is connected. In this state, the air pump 16 automatically operates, and the air flow from the air pump 16 is forced into the cartridge housing 6 through the air flow path, and the pressure of the air inside the cartridge housing 6 increases. However, by compressing the built-in ink storage bag 5, the ink inside is pressurized. As a result, the ink in the ink storage bag 5 is fed under pressure through the mouthpiece 8 and the compressor 9 connected thereto, through the ink supply pipe 10 and the filter 11, and from the inlet means 4 of the recording end to the inside. and overflows from nozzle 1 to the outside. At this time, air bubbles and foreign matter in the nozzle 1 and the recording head are discharged to the outside of the nozzle 1 together with overflowing ink, and the nozzle and other parts are cleaned and no longer clogged.

Next, when the above purge operation is completed and printing is started again, the power to the connecting means 14 is turned off, thereby cutting off the solenoid coil INLK, and the movable shaft 15
By returning to its original state, the tip of the movable shaft 15 holding the pressure contact member] 7 separates from the outer casing of the cart 1 and the main casing 6. At the same time, the source of the pressurizing air pump 16 is also cut off and the pressure feeding operation is performed. will also stop. Thus, the pressurized air within the cartridge housing 6 flows out through the air holes 7 to the outside air, and the air inside the cartridge is maintained at atmospheric pressure, allowing ink droplet ejection by the hydrostatic ink.

Next, the ink supply operation of the inkjet recording apparatus according to the present invention will be explained based on FIG. 2. In the figure, P is a recording paper, and 21 is a cylindrical platen for feeding the recording paper P. The platen 2] is driven and rotated by a motor or the like (not shown), and conveys the paper P in close contact with the platen 21.

A recording head having a plurality of nozzles 1 is mounted on a carriage υ, and a recording paper P is moved in the same direction as the axis of a platen 21 by a wire or a belt (both not shown) and a motor (not shown) connected to the carriage B. During this left and right movement, nozzle 1
Ink droplets are ejected from the recording paper P toward the recording paper P to form characters or images in a donto matrix shape on the recording paper.

If air bubbles or solid matter get into the recording head, it will not be possible to obtain good printing as described above, so check the The ink in the ink storage bag is forced into the recording head to forcibly eject and purge the air bubbles and solid matter in the ink flow path. For this purpose, the carriage 2z on which the recording head is mounted is moved in the direction of the cleaning roller 2.3 provided in the axial direction of the platen 21.
The nozzle 1 and the outer periphery of the cleaning loaf Z3 are set at a position IM (purge position) where they are close to each other and face each other. FIG. 2 shows a schematic diagram of this state. In the figure, the cleaning roller z3 is rotatable by being powered by a 9-ohm wheel fixed coaxially, a worm meshing with the 9-ohm wheel, and a driving motor 24.

On the −F side of the cleaning roller B, close to the outer periphery of the roller, a waste liquid receiver is provided, a handling ridge 5 is provided in the pipe 26, and a collection tank 27 along the screen and a suction air pump are provided. It is connected sequentially.

As described above, in the ink jet recording apparatus according to the present invention, the systems for performing the purge operation can be broadly classified into the following three systems.

(1) An air pressure feed line running from the processing air pump 16 to the cartridge housing 6 via the connecting means 14; (2)
(3) Cleaning roller okara waste liquid receiver, waste liquid collection tank 2;
7. The suction system path for air and waste ink leading to the suction air pump, and each thread path for performing the above purging operation is controlled by the microconbeater (hereinafter abbreviated as CP TJ) 3 ('1, i.e. , the two air pumps 16° and the connecting means 146 are started and stopped by the CPU 30 commands.

At the time of recording, both the pressurizing air pump] 6 and the suction air pump 28 are in a stopped state, and the connecting means 14 is in a stopped state.
The air hole 7 is opened and the inside of the cartridge case 6 is at atmospheric pressure. In this state, the ink in the ink storage bag 5 is circulated and replenished into the recording head, and ink droplets are ejected in response to an electrical signal from the electronic pulse generator 13.

When a defective ink droplet ejection is detected due to clogging of nozzle 1 as described above during recording, or when preventive ejection is performed intermittently at fixed intervals to prevent clogging, or before starting printing operation, etc. When a purge operation becomes necessary for some reason, first, in response to a command from the CPTJ30, the recording head is moved to a predetermined position (17) set at a position other than the conveyance position of the recording paper P, and the nozzle 1 is
and the cleaning roller z3 are opposed to each other. Next, the solenoid of the connecting means I4 is turned ON by a command from the CPU 30, the movable shaft 15 protrudes, and the pressure contact member 17 at the tip is pressed (IJ).
The outer wall around the air hole 7 of the wooden case 6 is pressed into contact with the pressurized air pump 16 and the ink cartridge cartridge in a hermetically sealed manner.

Subsequently, according to a command from the CPU 30, both the pressurizing air pump 6 and the suction air pump are turned on and started. As a result, pressurized air from the pressurized air pump 16 is forced into the cartridge housing 6 via the connecting means 14, and the inside of the housing 6 is brought into a new pressurized state. As a result, the ink in the ink storage bag 5 is pressurized, and this pressurized ink is transferred to the mouthpiece 8, the connector 9, and the ink supply pipe 10.
, is press-fitted into the recording head via the filter 11,
It follows the common ink chamber 3 and pressure chamber 2 and overflows from the nozzle 1 to the outside. At this time, air bubbles and solid matter in the ink flow path, especially the nozzle 1, are swept away and the inside of the flow path is cleaned.

On the other hand, the ink overflowing from the nozzle is discharged onto the outer circumferential surface of the cleaning roller B, which is disposed close to and facing the nozzle 1, and is carried on the circumferential surface of the rotating roller B, and is then sent to the waste liquid receiver below. It falls along 5. The waste liquid receiver 25 is suctioned by the suction air pump 4, and completely absorbs the ink flowing down on the surface of the cleaning roller swamp. The ink that has entered the waste liquid receiver 5 is drawn by the suction air flow and enters the waste liquid collection tank 27 through the pipe 26.

In this way, when the purge operation is completed, the CPU 30
With this command, both air pumps 16 and 4 are turned off and the air flow is stopped. Subsequently, the solenoid of the connecting means 14 is turned OFF in response to a command from the 1cPU 30, and the movable shaft 15 returns to its original position, thereby disconnecting the cartridge housing 6 and allowing the pressurized air in the cartridge housing 6 to pass through the air hole 7. It flows out into the outside air and returns to atmospheric pressure. As a result, the pressure of the ink inside the ink storage bag 5 also returns to atmospheric pressure. After a slight delay, the ink pressure in the recording head communicating with one ink in the ink storage bag 5 also gradually decreases, and gradually returns to atmospheric pressure. When the ink pressure within the recording head returns to approximately atmospheric pressure, the recording head leaves the purge position and shifts to printing operation.

In addition, in the above explanation, two dedicated pumps 1 are used for pressurization and suction.
6 and 4, but it is also possible to perform both pressurization and suction using one air pump. For example, it may be driven by a motor, an electromagnetic actuator, etc.). Such means help reduce costs and reduce the installation space.

FIG. 3 is a schematic diagram showing another embodiment according to the present invention.

This does not use the connecting means 14 having the movable shaft 15,
This pressurizing mechanism includes a control valve 40 that is fixed to the recording device. The insertion opening of the cartridge loading chamber 41 that stores the ink cartridge is sealed with a sealing member (for example, 01J, etc.).
) 42 with a sealing lid 43, and has a structure that is shut off from outside air. Further, an air intake port 44 is opened in a part of the wall of the cartridge loading chamber 41, and communicates with the pressurizing air pump 16 through a pipe. At the same time, the air intake 44 is controlled ff4o.
It reaches the air outlet 45 through the air outlet 45 and communicates with the outside air. The control valve 40 is a solenoid valve or other fluid control valve operated by a solenoid, and turns on the air pressure in the air flow path.

OFF control.

When performing a purge operation, first close the control valve 40, then operate the pressurizing air pump 16 to introduce pressurized air from the air intake port 44 into the air hole 7 of the cartridge housing 6, thereby increasing the air pressure inside the housing 6. When the ink storage bag 5 is raised and the ink storage bag 5 is pressurized, the contained ink is pressurized and is ejected from the nozzle 1 of the recording head to the outside together with air bubbles and solid matter in the same manner as described above. The operation for collecting the ejected ink is also the same as described above. After the purge is completed, the operation of the pressurizing air pump 16 is stopped, and at the same time, the control valve 40 is opened. As a result, the pressurized air within the cartridge housing 6 passes through the air hole 7, the air intake port 44, and the control valve 40, and flows out from the air discharge port 45, and the ink pressure returns to atmospheric pressure. Printing is possible in this state.

Note that when changing the ink cartridge, the sealing lid 43 is opened and closed.

In FIG. 4, the pressurizing means is a manual means instead of an electric air pump, and the connecting means is further simplified. A tapered hollow protrusion 51 protrudes from a part of the ink cartridge housing 6 in a position parallel to the mouthpiece 8, and the inner surface of the hollow protrusion 51 forms an air hole 7. A connecting member 52 having a shape to be fitted and connected to the hollow protrusion 51 is provided inside the cartridge loading chamber 41 .

The other end of the connecting member 52 is connected to a pipe 53 and further connected to a manual blower connection. The manual blower has a hemispherical or lantern-like shape made of an elastic flexible wall, and an air hole 54 is opened in a part of the wall. In this open state,
From the manual blower connection pipe 53, connecting member 52, hollow protrusion 5
1 to the cartridge housing 6 are all at atmospheric pressure. Inkjet recording is performed in this state. The manual blower is made of natural rubber, synthetic rubber, plastic, or the like.

When purging is required, the air hole 54 of the manual blower 50 is closed and compressed by the finger 55, and the air is compressed by reducing the volume, thereby increasing the air pressure inside the cartridge housing 6. , the contained ink is pressurized and ejected from the nozzle 1 in the same manner as described above. After the purge is completed, when you release your finger 55 from the air hole 54 of the manual blower 50,
The pressure inside the blower 54 immediately returns to atmospheric pressure, and the air pressure and ink pressure inside the cartridge case also return to atmospheric pressure, making it possible to print. This method has a simple structure and is effective when a relatively small pressing force is required.

FIG. 5 is a schematic cross-sectional view showing still another embodiment of the present invention. This uses a heating chamber 60 instead of the pressurizing air pump 16 in FIGS. 1 and 2.

The heating chamber 60 has an electric heater 62 provided on the inner wall of a tightly sealed casing 6, and has an opening in a part of the outer wall, communicating with the pipe J8.

When purging is required, the connecting means 14 is turned ON, the movable shaft 15 is driven, and the cartridge housing 7 is closely coupled with the air flowing from the heating chamber 60 through the connecting means to the cartridge housing 6. Completely seal the channel. At the same time, the heater 62 in the heating chamber 60 is turned on to raise the temperature in the heating chamber, and the resulting increase in air pressure caused by thermal expansion of the air is used to increase the air pressure inside the cartridge housing and, furthermore, the ink pressure. be. This method does not require a power drive unit such as an air pump or an electromagnetic operating part such as a control valve, has a simple structure, and is easy to maintain. However, each component must be heat resistant. .

Furthermore, various types of pressurizing means can be used in addition to the above-mentioned air pump 16, manual blower 50, and heating chamber inlet. - Examples include the use of liquefied gases. This is done by providing a liquefied gas container and a control valve in place of the pressurized air pump 16 in FIGS. 1 and 2, and performing pressurization and release operations in conjunction with the connecting means 14 for a short time. Suitable when high pressure is required.

The inkjet recording apparatus of the present invention configured as described above increases the gas pressure within the cartridge housing that houses the ink storage bag containing the recording ink to eliminate air bubbles and solid matter within the recording head during non-recording. It is ejected together with ink, and its operation is reliable, accurate, and highly reliable.
It is characterized by easy operation of attaching and detaching the cartridge, and a simple structure, which is extremely effective in practical use.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the inkjet recording device according to the present invention, FIG. 2 is a schematic diagram illustrating the operation of the inkjet recording device according to the present invention, FIGS. 3 and 4,
FIG. 5 is a sectional view showing another embodiment of the ink pressurizing means for an inkjet recording apparatus according to the present invention. 1... Nozzle 2... Pressure chamber 3... Common ink chamber 5... Ink storage bag 6... Cartridge housing 7... Air hole 8... Mouth part 9
...Connector 10...Ink supply pipe 14...
Connecting means 15...Movable shaft 16...Air pump for pressurization %...Cleaning roller 5...Waste paper receiver n...Waste liquid collection tank A...Air pump for suction 30...Microcomputer (CPU) )50・
・・Manual blower 4 () ・Control side 1 valve 60 ・Heating chamber representative Yoshimi Kuwahara

Claims (1)

[Claims] In an ink sheet recording device having an ink cartridge type recording head that pressurizes ink in a pressure chamber and jets the ink from a communicating nozzle, an ink storage bag made of a flexible material filled with recording ink is used. An almost airtight ink cartridge having a built-in gas inlet and an air pressurizing means are provided on the outside of the ink cartridge, and gas is forcibly introduced from the nitrogen inlet of the ink cartridge during non-recording, and the ink cartridge is An ink sheet recording apparatus characterized in that the pressure within the cartridge is increased to eject air bubbles and the like within the cartridge to the recording medium along with ink.