JPH07144413A - Ink-jet printer - Google Patents

Abstract

PURPOSE:To provide an ink-jet printer which avoids ink from being infiltrated into a negative pressure-generating means when ink is sucked through the nozzle of an ink-jet head by the negative pressure-generating means. CONSTITUTION:A capping means for covering the nozzle of an ink-jet head with a cap is provided. An air discharge port 38 connected to the air suction port of a negative pressure-generating means is formed to the upper part of a waste ink reservoir 25 having an ink suction port 37 connected to the cap. A float valve 42 which has a closing part 41 for closing the air discharge port 38 and is formed of the material having a specific gravity smaller than the specific gravity of ink is provided freely movably upward and downward to the waste ink reservoir 25. Thereby ink sucked through the nozzle is directly stored in the waste ink reservoir 25. When ink in the waste ink reservoir 25 reaches a saturated state, the float valve 42 is floated to close the air discharge port 38.

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 having a capping means for preventing nozzles of an ink jet head from drying and a negative pressure generating means for sucking ink from the nozzles to recover the clogging of the nozzles.

[0002]

2. Description of the Related Art In an ink jet printer in which a carriage having an ink jet head is moved along a platen and ink is ejected from the ink jet head, when it is in a non-printing state for a long time,
A capping means for covering the nozzle of the inkjet head with a cap to prevent the nozzle from drying, a cleaning means for cleaning dust and foreign matters adhering to the nozzle,
It is common to equip a maintenance station equipped with a negative pressure generating means such as a pump for sucking ink and bubbles dried and clogged in the nozzle.

For example, as described in JP-A-2-243353, a capping mechanism for preventing the nozzles of the recording head from drying, a pumping mechanism for applying a negative pressure to the inside of the capping mechanism, and a waste ink reservoir. Is sequentially connected, and the ink sucked from the nozzle is stored in a waste ink reservoir via a pumping mechanism.

Further, as described in JP-A-64-64853, a waste ink reservoir is connected between a cap member covering a nozzle and a pump so that ink sucked from the nozzle does not pass through the pump. There is one that is designed to store directly in the waste ink reservoir.

[0005]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2-24335
In the device described in Japanese Patent No. 3, since the ink sucked from the nozzle flows to the pumping mechanism, if the state left as it is for a long time after the pumping mechanism is operated, the ink remaining inside the pumping mechanism is solidified. Then, the pumping mechanism may be disturbed. In addition, an ink-repellent material must be used to prevent ink clumping, and an ink-resistant material must be used to manufacture the pumping mechanism to prevent ink corrosion, which increases costs.

Further, in the one disclosed in Japanese Patent Laid-Open No. 64-64853, the ink sucked from the nozzle can be directly stored in the waste ink reservoir, but when the ink in the waste ink reservoir is full, excess ink is stored. Will flow into the pump, causing the pump to malfunction. For this reason, if the capacity of the waste ink reservoir is increased, the apparatus becomes large in size, and a pump having a high suction capacity must be used, which also increases the cost.

[0007]

SUMMARY OF THE INVENTION The present invention is an ink jet printer for moving an ink jet head relative to a print sheet to eject ink from the nozzles of the ink jet head to perform printing, and a cap is provided on the nozzle. A capping means for covering is provided, and an air outlet connected to the air inlet of the negative pressure generating means is formed above the waste ink reservoir having an ink inlet connected to the cap, and the air outlet is closed. A float valve formed of a material having a specific gravity smaller than that of the ink is provided in the waste ink reservoir so as to be vertically movable.

[0008]

By making the inside of the waste ink reservoir into a negative pressure state by the negative pressure generating means, the ink sucked from the nozzle through the cap can be flowed directly to the waste ink reservoir.
In addition, as the amount of ink accumulated in the waste ink reservoir increases, the float valve is floated up and the air outlet is closed by the closed portion of the float valve, so that the ink enters the negative pressure generating means such as a pump. Can be avoided in advance.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. Although only one side is shown in FIGS. 4 to 6,
A plurality of guide shafts 2 are installed on opposite side plates 1, and a carriage 3 is slidably fitted on these guide shafts 2. An ink cartridge 8 including an ink jet head 6 having a nozzle 5 facing the platen 4 and an ink tank 7 is detachably mounted on the carriage 3.

The carriage 3 is driven beyond the print area to the non-print area, and the paper feed motor 9 is provided in the non-print area. A drive gear 11 is fixed to one end of a rotary shaft 10 of the paper feed motor 9, and a platen gear 12 is fixed to an end of the platen 4. The drive gear 11 and the platen gear 12 are composed of a plurality of gears 13, 1.
They are connected by 4.

Further, a frame 16 is fixed to a support 15 which holds the paper feed motor 9, and the frame 1
6 includes two shafts 1 parallel to the guide shaft 2.
7 are provided, and a slider 19 having a projecting piece 18 protruding toward the guide shaft 2 side is slidably fitted to these shafts 17. The return spring 20 moves the slider 19 to the home position (on the side of the support 15).
Is urged by. Further, a cap 21 is slidably held on the slider 19 in a direction orthogonal to the moving direction of the carriage 3. Furthermore, the frame 16 includes
Roller 22 rotatably provided on the lower surface of cap 21
Is formed with a guide groove 23. The guide groove 23 is inclined toward the guide shaft 2 side from the right end of the frame 16 toward the center part and is parallel to the guide shaft 2 from the center part to the left end. Stipulated in. Thus, the shaft 17, the slider 19, the return spring 20, the roller 22 provided on the cap 21,
A capping means 24 is formed by the guide groove 23. That is, the capping means 24 is
The linear movement of the carriage 3 outside the printing area is converted into a direction Y orthogonal to the linear movement direction X and transmitted to the cap 21, whereby the cap 21 is attached to and detached from the nozzle 5.

Next, a waste ink reservoir 25 is fixed to the left side plate 1 and a pump 26 as a negative pressure generating means is fixed to the support 15. The cap 21
The tube 27, one end of which is connected to the
The cutout 28 is formed through the cutout 28, and the tip of the cutout 28 is connected to the waste ink reservoir 25. The pump 26 is an operating rod 3 which is reciprocated in the axial direction by the rotation of the paper feed motor 9.
2 and a diaphragm (not shown) connected to the operating rod 32, and a negative pressure is generated by the amplitude operation of the diaphragm. The air suction port 29 of the pump 26 and the waste ink reservoir 25 are connected by a tube 30, and the exhaust pipe 31 of the pump 26 is open toward the atmosphere. Further, one end of a U-shaped tube clamp 33 having a shape that holds the tube 27 is fixed to a side surface of the slider 19 on the side plate 1 side.

Next, the structure of the waste ink reservoir 25 will be described with reference to FIGS. 1 and 2. FIG. 1 shows A- in FIG.
FIG. 2 is a plan view showing a vertical sectional side view of the line A portion. The waste ink reservoir 25 has an ink storage chamber 34 and a float working chamber 35.
And are formed. The ink storage chamber 34 is provided with an ink absorber 36 whose height is limited so that a space portion 34a is formed in the upper portion thereof. In addition, an ink inlet 37 connected to the cap 21 via the tube 27 and an air connected to the air inlet 29 of the pump 26 via the tube 30 are provided above the waste ink reservoir 25. A discharge port 38 is formed. further,
Partition wall 3 for partitioning the ink storage chamber 34 and the float working chamber 35
A cutout 39 communicating with the space 34a and a cutout 40 located at the bottom are formed in 5a. Therefore, in the float working chamber 35, the closing portion 4 for closing the air outlet 38 is provided.
A float valve 42 having 1 at the top is provided so as to be vertically movable. The float valve 42 is made of a material having a specific gravity smaller than that of the ink.

In such a configuration, the state shown in FIG. 4 is a state in which the carriage 3 is located in the print area. Printing is performed by ejecting ink from the nozzles 5 of the inkjet head 6 onto the recording paper on the platen 4 while the carriage 3 moves in the printing area. In this way, when the carriage 3 is located in the print area, the slider 19 is located on the support body 15 side by the pressure of the return spring 20. In this state, since the roller 22 at the lower end is located at the right end of the guide groove 23, the cap 21 is retracted to a position away from the guide shaft 2. The stop position of the carriage 3 when printing is not performed or when the power is turned off is the capping position shown in FIG.

The carriage 3 is driven and stands by at the capping position shown in FIG. 5 until the print data is output, and is kept stopped at this capping position even when the power is turned off. The carriage 3 moves from the state shown in FIG. 4 to the state shown in FIG.
When it moves to the capping position as shown in
Is pushed by the carriage 3, the slider 19 moves to the side plate 1 side together with the cap 21 against the pressure of the return spring 20. At this time, since the roller 22 of the cap 21 moves along the inclined portion of the guide groove 23, the cap 21 advances toward the guide shaft 2 side and covers the nozzle 5. This prevents the ink in the nozzle 5 from drying.

When the user operates a priming key (not shown), as shown in FIG.
Is driven to the pumping position on the side plate 1 side. In the process in which the carriage 3 moves from the capping position shown in FIG. 5 to the pumping position shown in FIG.
Since it moves in the horizontal part of 3, the relative position of the nozzle 5 and the cap 21 does not change. In this state, the end of the tube clamp 33 contacts the left side of the frame 16, so that the tube 27 is pinched and crushed. Then, by rotating the paper feed motor 9, the operating rod 32 of the pump 26 is driven, and the vibration of the diaphragm accompanying this operation expands the suction side volume. At this time, the suction side tube 27 is clamped by the tube clamp 33 and maintained in the closed state, so that a negative pressure is generated on the suction side of the pump 26. Then, the paper feed is executed, and the carriage 3 again.
Move to the capping position on the right side (Fig. 5),
The slider 19 moves to the center of the frame 16 together with the cap 21 by the pressure of the return spring 20, and the tube clamp 33 separates from the left side of the frame 16 to loosen the gripping force on the tube 27. Due to the negative pressure in 25, the ink in the nozzle 5 is sucked out through the cap 21. The sucked ink is stored in the waste ink reservoir 25.

As described above, after the carriage 3 is stopped at the capping position for a certain period of time to suck the ink from the nozzles 5, the carriage 3 is moved to the left until the cap 21 is separated from the nozzles 5. During this time, the pump 26 is driven by the paper feed motor 9 to suck the ink accumulated in the cap 21 into the waste ink reservoir 25, and then the paper feed motor 9 and the pump 26 are stopped, and the carriage 3 is shown in FIG. The nozzle 5 is moved to the capping position to maintain the state in which the nozzle 5 is sealed with the cap 21.

FIG. 3 shows how ink is stored in the waste ink reservoir 25. Ink 43 sucked from the nozzle 5
Flows in the direction of arrow B. As shown in FIG. 3A, the ink 43 flowing into the waste ink reservoir 25 is absorbed by the ink absorber 36.
Are absorbed from the upper part of the ink absorber 36 and move downward due to the capillary action of the ink absorber 36. In this case, since the space portion 34a is formed in the upper portion of the ink absorber 36 and the air discharge port 38 is connected to the space portion 34a through the notch 39, the arrow C is directed from the air discharge port 38 toward the pump 26. Air flows in the direction, but does not reach the ink 43.

FIG. 3B shows a state in which the amount of the ink 43 that can be absorbed by the ink absorber 36 reaches a saturated state, and further more ink 43 flows into the waste ink reservoir 25. The ink 43 in the storage chamber 34 flows from the notch 40 into the float working chamber 35. As a result, the float valve 42 floats, and as the amount of the ink 43 accumulated increases, the float valve 42 floats to the uppermost end and the air outlet 38 is closed at the closing portion 41, as shown in FIG. 3C. Block. As a result, it is possible to prevent the ink 43 from entering the pump 26 through the air outlet 38.

[0020]

As described above, according to the present invention, the capping means for covering the nozzle of the ink jet head is provided, and the air suction of the negative pressure generating means is provided above the waste ink reservoir having the ink suction port connected to the cap. A float valve formed of a material having a specific gravity smaller than the specific gravity of ink is provided in the waste ink reservoir so as to be movable up and down. Therefore, by making the inside of the waste ink reservoir into a negative pressure state by the negative pressure generating means, the ink sucked from the nozzle through the cap can be directly flown to the waste ink reservoir,
Further, as the amount of ink in the waste ink reservoir increases, the float valve is floated up, and the air discharge port is closed at the closed portion of the float valve, so that ink is generated in the negative pressure generating means such as a pump and its peripheral portion. It is possible to avoid the flowing state in advance, thereby preventing the occurrence of a failure in the peripheral portion including the negative pressure generating means, and along with this, it is possible to use inexpensive materials other than ink-resistant and ink-repellent materials. It is possible to reduce the cost by manufacturing the negative pressure generating means and the parts around the negative pressure generating means using the material.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a waste ink reservoir according to an embodiment of the present invention.

FIG. 2 is a plan view showing a waste ink reservoir.

FIG. 3 is a vertical cross-sectional side view showing how ink is stored in a waste ink reservoir.

FIG. 4 is a plan view showing a printed state.

FIG. 5 is a plan view showing a capping operation of a nozzle.

FIG. 6 is a plan view showing a pumping operation of the nozzle.

[Explanation of symbols]

 5 Nozzle 6 Inkjet Head 21 Cap 24 Capping Mechanism 25 Waste Ink Reservoir 26 Negative Pressure Generating Means 29 Air Suction Port 37 Ink Suction Port 38 Air Discharge Port 41 Closure 42 Float Valve 43 Ink

Claims (1)

[Claims] 1. An inkjet printer, wherein an inkjet head is moved relative to a print sheet to eject ink from nozzles of the inkjet head for printing, and capping means for capping the nozzles is provided. An air discharge port connected to the air suction port of the negative pressure generating means is formed in the upper portion of the waste ink reservoir having the ink suction port connected to the An inkjet printer, wherein a float valve made of a material having a specific gravity smaller than that of the specific gravity is provided in the waste ink reservoir so as to be vertically movable.