JPH0117860B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a suction recovery device for an inkjet recording device, and in particular, by moving a piston in one direction within the cylinder, the negative pressure generated in the cylinder is transferred to the nozzle of the inkjet recording device. The present invention relates to a suction recovery device for an inkjet recording apparatus, which recovers ink ejection from the nozzle by suctioning the ink.

In conventional suction recovery devices of this type, by the time the inkjet recording device is shipped, ink has entered the suction recovery pump due to suction recovery operations for printing checks and recovery operations for ink discharge failures. The ink that has entered the suction recovery pump will adhere to the valve of the suction recovery pump.
If the pump is left at a high temperature for a long time after shipment, or if the suction recovery pump is not used for more than half a year, there is a high possibility that the valve will become stuck due to evaporation of ink moisture. If the ink discharge valve of the suction recovery pump becomes stuck, the recovery function for resolving ink discharge failure will be extremely degraded.

1 and 2 show an example of a conventional suction recovery pump for an ink jet recording apparatus. In the figure, 1
2 is a cylinder, 2 is a piston provided in the cylinder so as to be able to move up and down, 3 is a piston return spring that holds the piston in a normal position, that is, a non-depressed position, and 4 is a capping device attached to a nozzle of an inkjet recording device. The connected suction port, 5, indicates the discharge port communicating with the atmosphere. A discharge hole 6 is formed in the piston 2, and a valve 7 for opening and closing the lower end thereof is provided, and the valve 7 is made of a thin film. In addition, in the figure, 8 and 9 indicate O-rings. This suction recovery pump expands the volume of the space 10 in the cylinder 1 by moving the piston in one direction (in the illustrated example, by pushing it downward) to generate negative pressure. Ink jetting from the nozzles is restored by introducing pressure to the nozzles of the inkjet recording device and sucking ink. In this pump, the valve 7 is made of a thin film, and the pipe resistance of the suction port 4 on the nozzle side is considerably larger than the pipe resistance of the valve discharge hole 6, so pressure is applied momentarily when the valve 7 opens. Even if this is done, no pressurizing force is generated on the side of the suction port 4, and the meniscus of the nozzle is not adversely affected. The two-dot chain line in FIG. 2 indicates the sucked ink 10A.
The state in which valve 7 is opened and discharged is shown. But valve 7
If the ink sticks, the sucked ink will not be discharged outside the cylinder. For this reason, the sucked ink must flow backwards, and pressurizing force is transmitted to the nozzle, causing a situation in which air bubbles are forced into the nozzle.
In this case, ink will not be ejected.

FIG. 3 shows another example of a suction recovery pump for a conventional inkjet recording apparatus, and FIG. 4 shows a state in which this suction recovery pump and the inkjet recording apparatus are connected. In the figure, 11 is a cylinder, 12 is a piston provided to move up and down within this cylinder, 13 is a piston return spring that holds the piston in a normal position, that is, a non-pressed position, and 14 is a nozzle and a sub-tank of the inkjet recording device. 15 indicates a suction port communicating with the atmosphere, and 15 indicates an exhaust port communicating with the atmosphere. The suction port 14 is formed with a valve sealing portion 16A in which a valve 17A is disposed, and the discharge port 15 is formed with a valve sealing portion 16B in which a valve 17 is disposed.
B is placed.

The inkjet recording device has a support 18 arranged to slide along a guide and a sub-tank 19 supported on the support. ). A capping device 21 attached to the inkjet recording device is connected to the valve sealing portion 16A by a connecting pipe 22.
It is connected to the suction port 14 via the valve 17A, and
An air layer 23 within the sub-tank 19 communicates with the suction port 14 through a connecting pipe 24 . In Figure 3, 25,2
6 indicates an O-ring.

In the suction recovery pump shown in FIG.
Instead of the valve 7 shown in FIG.
7A and 17B are provided. When the piston 12 is pushed down, the air 27 in the cylinder 11 expands in volume and generates negative pressure. At this time, the valve 17B is closed and the valve 17A is opened, applying negative pressure to the suction port 14 and generating this negative pressure. The pressure acts on the capping device 21 through the connecting pipe 22 to restore ink ejection from the nozzles of the inkjet device, and the negative pressure acts on the air layer 23 of the sub-tank 19 through the connecting pipe 24 to remove the ink from the ink tank. It acts to suck ink into the sub tank. In this suction recovery pump, unlike the suction recovery pump shown in FIG. 1, when the valve becomes stuck, a force acts to release the valve from sticking. However, the valve 17A on the nozzle side
The force applied to the piston 12 is the negative pressure generated when the piston 12 is pushed down, and the maximum value of the unsticking force is negative pressure, so the limit is 1 atm. Because it is easy, the release power is further reduced. In addition, in the case of the structure in which air is sucked into the suction pump side when the amount of air in the sub-tank 19 becomes large as shown in FIG. Since air is sucked into the cylinder, the decompression does not become too large,
The force for releasing the valve from sticking becomes weaker. Further, when the air suction pipe is located at the position of the connecting pipe 22, as indicated by the two-dot chain line 24' in FIG. 3, the structure becomes larger and more complicated.

[Objective] The present invention has been made in view of the above-mentioned conventional technical problems.

The purpose of the present invention is to release the stuck valve with an extremely simple operation when the inkjet recording device is used for the first time, or when it has not been used for a long period of time, for example, more than half a year, even if the valve is stuck. It is an object of the present invention to provide a suction recovery device that can perform the following functions.

Another object of the present invention is to provide a suction recovery device that can apply pressure to a valve to release it without transmitting pressure to the ink ejection port side, thereby preventing the valve from sticking.

In order to achieve the above object, a suction recovery device for an inkjet recording apparatus according to the present invention includes a cap that covers an ejection port for ejecting ink provided in a recording head, and a cap that covers an ejection port for ejecting ink provided in a recording head, and a cap for discharging ink from the ejection port through the cap. a cylinder having a suction pump for suction, the suction pump having a piston and a suction port in which the piston slides, the suction port being disposed within a movement range of the piston and communicating with the cap; and a valve that can be opened and closed by the pressure difference generated between the atmospheric pressure and the air pressure inside the cylinder as the piston slides, and the pressure is reduced inside the cylinder by the movement of the piston in a predetermined direction. A suction operation is performed through the suction port by forming a space, and a closed space that generates a high pressure state inside the cylinder is formed by movement of the piston in a direction opposite to the predetermined direction. The valve is characterized in that the valve opens at .

[Example] The present invention will be explained in detail below using the drawings.

5 and 6 are schematic diagrams showing the structure of a suction recovery pump, which is a characteristic structure of the suction recovery device of the ink jet recording apparatus according to the present invention. In the figure, 31 is a cylinder, 32 is a piston, 3
3 is a discharge hole provided in the piston, and 34 is a valve.

According to the invention, the piston 3 in the cylinder 31
The stroke operation of 2 is divided into two stages, and the piston is moved in one direction within the cylinder 1 (in the case shown,
By moving the piston (downward), the ink discharge is restored by the negative pressure generated in the cylinder as in the conventional case, and the piston 3 is moved in the cylinder 31.
2 in the opposite direction (in the case shown, upwardly), a high pressure is created in the cylinder 31, which is directed to the stuck valve section and releases the stuck valve. In the illustrated embodiment, a piston return spring 35 is provided below the piston 32, and a pressure return spring 36 whose spring constant is larger than that of the piston return spring 35 is provided above the piston return spring 35. Thus, the spring 36 determines the steady state position of the piston 32 within the cylinder 31, and in the steady state the piston 32 is maintained in the position shown in FIG. Thus, the stroke motion of the piston 32 is caused by the stroke movement of the piston 32 against the force of the spring 35.
The stroke is divided into a stroke for pushing down the piston 2 and a stroke for pulling up the piston 32 against the force of the spring 36.

The piston 32 includes upper and lower O-rings 37,
38, a suction port 39 that communicates with the nozzle of the inkjet recording device through the cap of the capping device for covering the ink discharge port, and a suction port 40 that communicates with the sub-tank are connected to the O-ring 37 of the piston 32 in the above-mentioned normal position. , 38 into the cylinder 31. In the figure, 41
indicates an O-ring.

During ink discharge recovery operation of the inkjet device, when the piston 32 is pushed down against the force of the spring 35, the space 42 inside the cylinder 31 expands and generates negative pressure, which is applied to the suction port 39 and the cap. ,
and 40 to act on the nozzle and sub-tank to perform an ink ejection recovery action. At this time, the piston is returned to the normal position by the action of the return spring 35, and in this case, the pressurizing return spring 36 acts as a stopper for the piston return position.If the valve is stuck, in order to release the valve, the piston must be 32 against the force of the spring 36 to pull up the piston 32. As a result, the volume of the space 42 is reduced as indicated by 42A in FIG. 6, and a high pressure is generated. This causes high pressure to act on the valve 34, releasing it from its sticking. At this time, the two-stage O-rings 37 and 38 provided on the piston act to prevent high pressure from being transmitted to the nozzle and sub-tank of the inkjet recording device. In this structure,
The pressurizing force due to compression on the pressurized space 42A when releasing the fixation from the initial space 42 in the cylinder is:
A force of several kg can be easily obtained by manual force with a large stroke. Therefore, a pressure of 1 atmosphere or more can be easily generated, and the sticking of the valve can be easily and reliably released.

[Effects] As explained above, according to the present invention, it is possible to prevent the valve in the suction recovery device from sticking to the maximum extent through normal operation, and it is possible to always maintain the recording head in a good ink ejection state. can.

Further, after a predetermined negative pressure is generated within the pump, it can be transmitted to the cap and ink can be suctioned, thereby increasing the suction recovery efficiency.

Furthermore, even if the valve is stuck when starting to use it after being unused for a long time, it is possible to release the sticking of the valve with an extremely simple operation.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views showing an example of a conventional suction recovery pump, Figure 3 is a cross-sectional view showing another example of a conventional suction recovery pump, and Figure 4 is the suction recovery pump shown in Figure 3. FIG. 5 is a sectional view showing one embodiment of the suction recovery pump of the present invention, and FIG. 6 is a similar sectional view showing its operation. 1... Cylinder, 2... Piston, 3... Piston return spring, 4... Suction port, 5... Discharge port, 6
...Discharge hole, 7...Valve, 8,9...O ring, 1
0...Space between cylinders, 11...Cylinder, 1
2... Piston, 13... Piston return spring, 1
4... Suction port, 15... Discharge port, 16A, 16B
... Valve sealing part, 17A, 17B ... Valve, 18 ...
Support body, 19... Sub-tank, 20... Connecting pipe,
21...Capping device, 22...Connecting pipe, 2
3... Air layer, 24... Connecting pipe, 25, 26...
O-ring, 27... Space inside the cylinder, 31...
Cylinder, 32...piston, 33...discharge hole,
34... Valve, 35... Piston return spring, 36...
...Pressure return spring, 37, 38...O ring, 3
9, 40...Suction port, 41...O ring, 42,
42A... Space inside the cylinder.

Claims (1)

[Scope of Claims] 1. A cap that covers an ejection port provided in a recording head for ejecting ink, and a suction pump that sucks ink from the ejection port through the cap, the suction pump comprising: , a piston, a cylinder in which the piston slides, a cylinder disposed within a movement range of the piston, and having a suction port communicating with the cap; and atmospheric pressure and the cylinder as the piston slides; a valve that can be opened and closed by a pressure difference generated between the piston and the air pressure inside the cylinder, and the movement of the piston in a predetermined direction forms a depressurized space inside the cylinder, thereby opening the suction port. An inkjet recording device characterized in that a suction operation is performed through the cylinder, and the valve is opened by forming a sealed space in the cylinder that generates a high pressure state by moving the piston in a direction opposite to a predetermined direction. Equipment suction recovery device.