JPH0725032A - Ink jet printer - Google Patents

Abstract

PURPOSE:To provide a cap device in which unnecessary pressure is not applied to a nozzle. CONSTITUTION:A cap chamber 3 of a cap 2 is connected to a conduit 5 through a valve 4 and opened with the atmosphere through a filter 6. Magnetic fluid 7 is present in the conduit 5 to move in the conduit 5 due to a pressure difference of both sides. A rise of an inner pressure of the chamber at the time of bringing into contact with the cap 2 is alleviated by the movement of the fluid 7. A temperature change in a capping state and an inner pressure change in the chamber at the time of atmospheric pressure change can similarly be absorbed. At the time of priming, the valve 4 is closed, and it is sucked by a pump 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer, and more particularly to an ink jet printer having a cap device.

[0002]

2. Description of the Related Art Generally, in an ink jet printer,
A cap device is used to prevent nozzle drying. In many cases, the cap device is composed of an elastic member such as rubber, which is brought into contact with the nozzle surface of the print head to block the nozzle from the atmosphere, thereby preventing the nozzle from drying.

However, since airtightness is required to prevent drying, the nozzle surface is brought into close contact with a high contact force. For this reason, the cap may be deformed, the internal pressure of the cap chamber may rise correspondingly, and air may be pushed into the nozzle, which may cause printing failure. Further, when the air in the cap chamber expands due to a change in temperature or a change in atmospheric pressure, the same problem occurs.

In order to avoid this problem, JP-A-61-1
As described in Japanese Patent Publication No. 21949, it is known that an atmosphere release valve is used to release a change in the internal pressure in the cap chamber when the cap is in contact with or away from the cap, so that unnecessary pressure is not applied to the nozzle. There is. Further, as described in Japanese Patent Laid-Open No. 60-260341, there is also known one in which a part of the cap is made flexible to obtain the same effect.

However, the method using the atmosphere release valve has a problem in that the atmosphere release valve is closed during capping, so that pressure fluctuations due to temperature changes and atmospheric pressure changes cannot be avoided. Further, if the atmosphere opening valve is opened during capping, there is a problem that evaporation from the nozzle increases and drying occurs.

A method of making a portion of the cap flexible is:
Even if the pressure fluctuation at the time of contacting the cap can be alleviated, it cannot be completely avoided. Further, when the ink is sucked from the nozzle in the priming operation, there is a problem that the negative pressure generated by the pump cannot be efficiently transmitted to the nozzle.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and is unnecessary for a nozzle when the cap is brought into contact with or separated from the nozzle surface, and when the temperature or atmospheric pressure changes. Inkjet equipped with a cap device that can effectively transmit the negative pressure generated by the pump even when the ink is sucked from the nozzle while preventing the infiltration of air into the nozzle without applying any pressure. It is intended to provide a printer.

[0008]

According to a first aspect of the present invention, in an ink jet printer for ejecting ink for printing, a cap having a cap chamber and one end of the cap via a valve are provided. 3. The invention according to claim 2, characterized in that it has a conduit communicating with the chamber and the other end of which is open to the atmosphere, and a non-volatile fluid movably arranged in a part of the conduit. Claim 1
The ink jet printer according to the item (4) is characterized by having a mechanism for moving the nonvolatile fluid to a predetermined position when the cap is separated from the print head.

The conduit can be arranged substantially horizontally, and a magnetic fluid can be used as the non-volatile fluid.

[0010]

According to the present invention, since the cap chamber communicates with the atmosphere through the non-volatile fluid movably arranged in a part of the conduit, the cap having high airtightness can be obtained. Further, the non-volatile fluid is moved when the cap is brought into contact with the cap, so that a change in the internal pressure in the cap chamber can be released, and air does not enter the nozzle.
Further, even when a temperature change or a pressure change occurs, the non-volatile fluid moves, so that it is possible to prevent unnecessary pressure from being applied to the nozzle.

Further, since the pipes are connected through the valve, when sucking the ink from the nozzle, the negative pressure generated by the pump can be efficiently applied to the nozzle.

Further, by providing a mechanism for moving the nonvolatile fluid to a predetermined position when the cap is separated from the print head, the position of the nonvolatile fluid can be kept at an appropriate position.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram of a main part of an embodiment of an ink jet printer of the present invention. In the figure, 1 is an inkjet head, 2 is a cap, 3 is a cap chamber, 4 is a valve, 5 is a conduit, 6 is a filter, 7 is a magnetic fluid, 8 is a magnet, and 9 is a pump. In this example, the magnetic fluid 7 was used as the non-volatile fluid.

The cap 2 is brought into contact with and separated from the nozzle surface of the ink jet head 1 by a driving mechanism (not shown). One end of the pipe line 5 communicates with the cap chamber 3 via the valve 4, and the other end is attached with a filter 6 and is open to the atmosphere. Since the filter 6 is provided to prevent the entry of dust and the like, it is not always necessary.
Not what you need. The magnetic fluid 7 has a size that closes the pipe line, and moves in the pipe line 5 due to the pressure difference between the two sides. The magnet 8 is a permanent magnet, and with respect to the conduit 5,
It is provided so as to be able to approach and separate, and regulates the position of the magnetic fluid 7. That is, when the magnet 8 is moved closer to the conduit 5, the magnetic fluid 7 moves to that position, and when the magnet 8 is moved away from the conduit 5, the magnetic fluid 7 becomes movable in the conduit.
When the amount of movement of the magnetic fluid 7 is large due to the thin pipe 5, the magnet 7 may be moved along substantially the entire region of the pipe 5 and then stopped at a predetermined position. An electromagnet may be used as the magnet 7.

2 to 5 are explanatory views showing an example of the operation of the embodiment shown in FIG. In the figure, the same parts as those in FIG.

FIG. 2 shows the state before capping, and the valve 5 is open. The cap 2 is the inkjet head 1
Away from. In this state, the magnetic fluid 7 can be held at a predetermined position by setting the magnet 7 at a predetermined position.

FIG. 3 shows the cap contact. At the same time when the cap 2 contacts the inkjet head 1, the magnet 7 separates from the conduit 5.

FIG. 4 shows a capping state in which the contact force is increased. When the pressure contact force of the cap 2 is increased and the cap 2 is deformed, a positive pressure is generated in the cap chamber 3, and this pressure causes the magnetic fluid 7 arranged in the pipe line 5 toward the atmosphere opening portion, It is relieved by moving in the direction of the arrow shown. Therefore, no unnecessary pressure is exerted on the nozzle. When the printing is stopped or the like, the cap is left in contact, and the state of this figure continues for a long time. During,
When the air in the cap chamber 3 expands or contracts due to the temperature increase or the atmospheric pressure decrease, the magnetic fluid 8 similarly moves in the pipe and relaxes the pressure fluctuation in the cap chamber 3. can do.

FIG. 5 shows the priming operation. As a nozzle maintenance method by mixing air bubbles, drying the nozzle, or the like, a negative pressure is applied to the cap chamber to suck ink from the nozzle. At this time, the valve 4 is closed. Therefore, the negative pressure generated by the pump 9 is efficiently transmitted to the nozzle.

FIG. 6 is a schematic configuration diagram of a main part of another embodiment of the ink jet printer of the present invention. In the figure, the same parts as those in FIG. 10
Is a non-volatile fluid. In this example, a bendable pipe line 5 was used.

When the non-volatile fluid is moved by the fluctuation of the internal pressure of the cap chamber 3, that is, in the state described with reference to FIGS. 3 and 4, the conduit 5 is stretched substantially horizontally.
Therefore, the operation described with reference to FIGS. 3 and 4 can be performed.

In order to return the moved non-volatile fluid to a predetermined position after the pressure change, the pipe line 5 is bent downward as shown in FIG. As a result, the non-volatile fluid 10 can move to the lowest point of the conduit 5 by its own weight and take a predetermined position.

In this embodiment, since the position of the non-volatile fluid 10 can be set by gravity, the non-volatile fluid is
The fluid is not limited to the magnetic fluid, and an appropriate fluid can be used.

[0024]

As is apparent from the above description, according to the present invention, a highly airtight cap can be provided without intruding air into the nozzle, and further, temperature rise and atmospheric pressure can be prevented during capping. Even if the pressure drops, the pressure adjusting mechanism can prevent unnecessary pressure from being applied to the nozzle. Further, since the valve is provided, there is an effect that the negative pressure generated by the pump can be efficiently applied to the nozzle when the ink is sucked from the nozzle.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a main part of an embodiment of an inkjet printer of the present invention.

2 is an explanatory diagram of a state before capping of the embodiment of FIG. 1. FIG.

FIG. 3 is an explanatory diagram of the embodiment of FIG. 1 when the cap is in contact.

FIG. 4 is an explanatory diagram of a capping state of the embodiment of FIG.

5 is an explanatory diagram at the time of priming operation of the embodiment of FIG.

FIG. 6 is a schematic configuration diagram of a main part of another embodiment of the inkjet printer of the present invention.

[Explanation of symbols]

1 inkjet head, 2 cap, 3 cap chamber, 4 valve, 5 pipe line, 6 filter, 7 magnetic fluid, 8 magnet, 9 pump, 10 non-volatile fluid.

Claims (2)

[Claims] 1. An ink jet printer for ejecting ink to perform printing, a cap having a cap chamber, a pipe line having one end communicating with the cap chamber via a valve and the other end opening to the atmosphere, and the pipe line. An inkjet printer having a non-volatile fluid movably disposed in a part of the ink jet printer. 2. The ink jet printer according to claim 1, further comprising a mechanism for moving the nonvolatile fluid to a predetermined position when the cap is separated from the print head.