JPH10297001A - Ink suction method for inkjet recording head - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To suppress bubbling during suction of ink from a recording head. SOLUTION: A small amount of ink D is discharged from a recording head 7, and ink is injected into a cap 32 (FIG. 5 (b)).
With the volume reduced by the ink, the recording head 7 is sealed, and the negative pressure of the pump unit 11 is applied to eject the ink from the recording head 7 (FIG. 5C). Suppresses bubbling by acting on the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink suction technique for an ink jet recording head which discharges ink droplets from nozzle openings in accordance with a print signal.

[0002]

2. Description of the Related Art An ink jet printer is provided with an ink jet recording head which receives supply of ink from an ink storage means, and a paper feeding means for moving a recording sheet relatively to the recording head. This is an apparatus that performs recording by ejecting ink droplets on recording paper while moving the recording head.

In order to prevent clogging due to volatilization of the ink solvent, or to fill the recording head with the ink in the ink container, the recording head is required to handle the relatively easy-to-dry liquid such as ink. A process of sealing with capping means and applying a negative pressure to forcibly discharge ink from nozzle openings is performed.

[0004]

The capping means comprises:
Since an ink absorbing sheet made of a porous material is contained for the purpose of holding a certain amount of ink and preventing drying of the nozzle openings at the time of capping, ink ejected from the recording head at the time of suction is stored in the capping means. Entrained air acts on the ink absorbing sheet to form bubbles, causing ink bubbles to adhere to the nozzle openings of the recording head, causing ink droplets to bend in flight during printing, and destroying the meniscus. . The present invention has been made in view of such a problem, and an object of the present invention is to prevent ink from adhering to nozzle openings by suppressing bubbling of ink in a capping device during ink suction. It is to propose a possible ink suction method.

[0005]

According to the present invention, there is provided an ink jet recording head for ejecting ink droplets corresponding to print data, and a recording medium selectively communicating with the atmosphere. While sealing the head,
In a cleaning method for an ink jet type recording apparatus including a capping unit receiving a negative pressure from a suction pump and a suction pump for supplying a negative pressure to the capping unit, a very small amount of ink is discharged from the recording head to the capping unit. Injecting ink, and sealing the recording head by the capping means,
Applying a negative pressure of the suction pump to the capping unit to suction ink from the recording head, wherein pores of the ink absorbing sheet housed in the capping unit are sealed with ink in advance, and capping is performed. The space volume of the means is reduced to suppress the entrainment of air and prevent the generation of bubbles.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 shows an embodiment of the present invention. In the drawing, reference numeral 1 denotes a carriage which is connected to a motor 3 by a timing belt 2 and is guided by a guide member 4 so as to be parallel to a platen 5. It is configured to move. Recording paper 6 on carriage 1
A recording head 7 for color printing is provided on a surface opposite to the recording head 6. The recording head 7 receives ink supplied from the ink cartridge 8 and discharges ink droplets onto the recording paper 6 to perform printing.

Reference numeral 10 denotes a capping device which is connected to a pump unit 11 via a tube, and has a size capable of sealing the nozzle opening surface of the recording head 7 in one space. When the operation is stopped and the ejection capacity is restored, the ink is forcibly discharged from the recording head 7 by receiving the supply of the negative pressure from the pump unit 11.

FIGS. 2 and 3 are a perspective view and an assembled perspective view, respectively, showing an embodiment of the capping device. In the drawings, reference numeral 12 denotes a slider, which is a carriage when the carriage 1 moves to a non-printing area. The upper surface of the base 13 is configured to move in the horizontal and vertical directions following the movement of the base 1.

A cap member 14 for sealing the nozzle opening surface of the recording head 7 is provided in one half of the printing area (left side in the figure) on the upper surface, and the other half which is an outer area (right side in the figure). A flag unit 16 is provided at the outermost end thereof.

The slider 12 has a projection 1 at the lower end on the outermost end side.
7, which slides on the guide surface 18 of the base 13 in contact with the guide surface 18, and has a projection 19 on the side of the print area, which is orthogonal to the moving direction of the carriage 1. Arm 2 having one end rotatably supported on base 13 by long groove 20a
0 and is rotatably supported at the other end of the base 13 and the arm 2.
The printing area is always urged by the compression spring 21 inserted between the printing area and the printing area so that the printing area side is upward. The protrusion 19 that engages with the arm 20 is formed with a through hole 19a that communicates with an ink suction port 25 of a cap 23, which will be described later, so that it also serves as a connection flow path.

On the other hand, the guide surface 18 of the base 13 has a low position 18a and a high position 18b so that the cap member 14 can occupy a position away from the nozzle plate and two positions elastically contacting the nozzle plate. And a slope 18c (FIG. 5) connecting them, and a stopper 22 for determining a limit point is formed at the outermost end of the high point 18b.

The cap member 14 is roughly divided into a cap 23 and a support frame 24 for holding the cap 23, as shown in FIG. The cap 23 is made of a synthetic resin such as rubber having ink resistance, and has an ink suction port 25 and an air communication port 26.

The ink suction port 25 and the air communication port 2
6 are conduits 2 each formed integrally with the cap 23.
7, 28, the valve unit 15 and the suction pump 1
1 connected. These conduits 27 and 28 are provided at intervals in the movement direction of the carriage 1, and the conduit 28 on the non-printing area side is configured to be longer than the other conduit 27, and the cap 23 is moved by the elasticity of the conduit 28. The printing area is configured to take a posture in which the printing area side is a lower part.

In the cap 23, first and second ink-absorbing sheets 30 and 31 made of a porous material having ink resistance and ink absorption are inserted so as to cover substantially the bottom surface. The located second ink absorbing sheet 31 is fixed by a protrusion 32 formed on the inner peripheral surface side of the cap 23.

The support frame 24 has a cap 23 on the bottom surface.
Are provided with holes 32, 32 passing therethrough, and a concave portion 33 formed at the center thereof is fitted into a projection 34 extending from the base 13 so that one side is provided between the conduit 27 and the slider 12. The projections 36 on the side portions are pressed by the spring 35 interposed so as to be biased toward the concave portion 3 of the slider 12.
7 and swingably attached.

The valve unit 15 is urged toward the valve seat side by a spring 40 and a valve seat 39 having an opening connected to the atmosphere communication port 26 of the cap 23 by a tube 38.
A valve body 42 having an operating rod 41 that is moved by the slider 12 abutting on the stopper 16.
The valve body 42 is configured as a normally closed valve that separates the valve body 42 from the valve seat 39 by the movement of the valve body 39.

In the ink jet recording apparatus thus constructed, the recording head 7 is moved to the home position so as to be opposed to the cap 23 (FIG. 5A), and a drive signal irrelevant to a print signal is applied to the recording head. To perform a flushing operation. The ink droplet D discharged from the recording head 7 is applied to the ink absorbing sheet 30 of the cap 23,
The liquid level of the ink rises from the time when the absorption reaches the saturation level (FIG. 5B).

When a certain amount of ink has accumulated in the cap 23, the carriage 1 is moved to a position where it can be sealed, the cap 23 is raised, and the recording head 7 is sealed with the cap 23. When the pump unit 11 is operated in this state, the ink K ′ is discharged from the recording head 7 into the space A ′ whose volume has been reduced by the ink K (FIG. 5C).

As a result, the amount of air entrained by the ink is smaller and the direct contact between the ink and the ink absorbing sheets 30 and 31 is smaller than when the ink is discharged into a cap having a large volume A which is not filled with ink in advance. Is prevented from foaming.

At the stage when the discharge of the ink from the recording head 7 is completed, the carriage 1 is slightly moved to such an extent that the sealing of the recording head 7 by the cap 23 can be maintained and the air opening port 26 can be opened. 11 is driven at a low speed to discharge the ink remaining in the cap 23 without applying unnecessary negative pressure to the recording head 7 (FIG. 5).
(D)).

In the above-described embodiment, the cap 23 is filled with ink by a flushing operation.
As shown in FIG. 5, the carriage 1 is further moved from the flushing position (FIG. 6A), and the recording head 7 is moved to the cap 23.
Then, the pump unit 11 is driven at a low speed to discharge a small amount of ink K ″ from the recording head 7 in this state (FIG. 6B).

As a result, the ink droplets D ejected from the recording head 7 are applied to the ink absorbing sheets 30, 31 of the cap 23.
When the absorption reaches saturation and the ink level rises to a predetermined position, the carriage 1 is moved to a position where it can be sealed, the cap 23 is raised, and the recording head 7 is moved.
Is sealed with a cap 23. When the pump unit 11 is operated at high speed in this state, the ink K 'is discharged from the recording head 7 into the space A' whose volume has been reduced by the ink K, and the ink K 'is reduced without being caught in the air and discharged without foaming. (FIG. 6 (c)).

At the stage when the discharge of the ink from the recording head 7 is completed, the carriage 1 is slightly moved to such an extent that the sealing of the recording head 7 by the cap 23 can be maintained, and the air opening port 26 can be opened, and then the pump is again turned on. The unit 11 is driven at a low speed to discharge the ink remaining on the cap 23 without applying unnecessary negative pressure to the recording head (FIG. 6 (d)).

[0024]

As described above, according to the present invention, a step of discharging a small amount of ink from the recording head and injecting the ink into the capping means, a step of sealing the recording head by the capping means, Applying a negative pressure of a suction pump to suck ink from the recording head, so that the pores of the ink absorbing sheet contained in the capping means are sealed in advance with ink, and the space of the capping means is provided. The volume can be reduced to suppress the entrainment of air, and the occurrence of bubbles during ink suction can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is a perspective view showing one embodiment of a capping device of the same device.

FIG. 3 is an assembled perspective view showing one embodiment of the capping device.

FIG. 4 is a sectional view of a main part of the same capping device.

FIGS. 5A to 5D are explanatory views each showing an embodiment of the ink suction method of the present invention.

FIGS. 6A to 6D are explanatory views showing another embodiment of the ink suction method of the present invention.

[Explanation of symbols]

 Reference Signs List 7 recording head 10 capping device 11 pump unit 23 cap 25 ink suction port 26 atmosphere communication port 31, 32 ink absorption sheet

Claims (3)

[Claims] 1. An ink jet recording head for ejecting ink droplets corresponding to print data, and capping means for selectively communicating with the atmosphere to seal the recording head and receive a negative pressure from a suction pump. A method of sucking ink of an ink jet recording head in an ink jet recording apparatus provided with a suction pump for supplying a negative pressure to said capping means, wherein a small amount of ink is discharged from said recording head and ink is injected into said capping means. An ink suction method for an ink jet recording head, comprising: a step of sealing the recording head by the capping unit; and a step of applying a negative pressure of the suction pump to the capping unit to suction ink from the recording head. . 2. The ink suction method for an ink jet recording head according to claim 1, wherein the step of injecting the ink is performed by applying a drive signal to the recording head. 3. The ink suction method for an ink jet recording head according to claim 1, wherein the step of injecting the ink is performed by a series of operations including a step of sucking the ink.