JPH0259354A - Purging unit - Google Patents

Abstract

PURPOSE:To prevent color mixture in each printing head by installing a check valve which allows ink flow toward only a discharge port side inside each inflow port which sucks ink from the tip of a printing head. CONSTITUTION:A chamber 31 consists of inflow ports 31-1 to 31-4 connected to a suction port 2 of a frame 1 through resin tubes 6-1 to 6-4 and an air hole 31-5 connected to a pressure release valve 5 through a resin tube 9, which are arranged on the upper plate 31a of a hermetically sealed container with a discharge port connected to a suction source on the bottom through a resin tube 7. Each inflow port 31-1 to 31-4 and the air hole 31-5 communicate with the discharge port 31b at the bottom of the hermetically sealed container. Consequently, ink sucked from each printing head 10-1 to 10-4 passes through the check valve 32 in each inflow port 31-1 to 31-4, flowing into the bottom of the chamber 31 separately. Ink mixed at the bottom flows back toward each tube 6-1 to 6-4 due to the check valve 32. However, ink mixture does not occur in a printing head because the ink does not diffuse.

Description

[Detailed Description of the Invention] [Summary] A purge unit of a drop-on-demand inkjet printer that prints various information in color by arranging a plurality of unique print heads that eject several color inks, respectively. Regarding this, the purpose is to provide a purge unit that prevents ink sucked and mixed during purging from spreading and prevents color mixture from occurring in each print head. In a purge unit that suctions and purges ink from each print head using a common suction source, inlets connected to tubes that suction ink from the print head are arranged on the upper plate, and on the suction side of each inlet. A check valve through which ink passes only in the suction direction is provided, and a chamber is provided between the print head and the suction source, and the chamber communicates the discharge port connected to the suction source with the inlet at the bottom of the sealed container. do.

[Industrial application field]

The present invention relates to a purge unit of a drop-on-demand type inkjet printer that prints various information in color by arranging a plurality of unique print heads that eject several color inks, respectively.

In particular, in the printing nozzle of an inkjet printer that prints in color, printing defects occur due to thickening of the ink in the nozzle or air bubbles entering the nozzle, so the ink and air bubbles in the nozzle are sucked.

A purge mechanism that prevents and restores printing defects by removal, a capping mechanism that seals around the nozzles of the print head to prevent ink from drying when the print body is stopped or the power is turned off, and a cleaning mechanism around the nozzles of the head. A wiper is installed to protect the vehicle. However, there is a possibility that the ink sucked into the purge mechanism may mix and spread to the nozzles of other color heads, so a new purge unit is needed that has a structure that prevents the sucked and mixed ink from flowing back into the print head. There is.

[Conventional technology]

A conventionally widely used purge unit has a print head 10-1°10-2.10- for each color of cyan, magenta, yellow-black, as shown in FIG.
3. Each frame 1-1 corresponding to 10-4,
1-2.1-3.1-4 and the frame 1-1.1-
A suction source 4 such as a reciprocating pump connected to 2.1-3.1-4 via a connecting fitting 3 and a resin tube, and an air pressure release valve 5 are provided.

Each of the frames 1-1 to 1-4 is provided with a rubber suction port 2 for sealing around the nozzle 10b on the tip end surface 10a of the print head 10 shown in FIG.

The frame 1 is fixed to a lever 12 that is rotatable around an axis XX. Note that in this example, a camping capping portion 8 is attached to the frame l.

As shown in FIG. 4, the connecting fitting 3 has an ink inlet 3-1.3- connected to the suction port 2 via resin tubes 6-1, 6-2, 6-3, and 6-4 on one side. 2.3-3
．． 3-4, and the pressure release valve 5 via the resin tube 9.
A vent port 3-5 is provided to connect to the suction side of the suction source 4 through a resin tube 7, and a discharge port 3b is provided on the other side to connect to the suction side of the suction source 4 via the resin tube 7.

As shown in FIG.
-1 to 1-4 (details of shaft attachment procedure not shown)
The hook is constructed by passing over a pair of rollers 14.

When not performing cleaning or purge operation, lever 12
is positioned at the retracted position shown in FIG. 6(a). In this state, the projection 12a of the lever 12, which is urged in the direction of the arrow by the spring 15, is engaged with the high portion 16-13 of the cam 16-1 of the camshaft 16, and is connected to the lever 12 via the link mechanism 17. The solenoid 18 is activated and holds the lever 12. This operating state of the solenoid 18 is realized by the notch 16-2 of the camshaft 16 opposing the contact 19a of the microswitch 19.

When purging is performed by the above purge unit, the tip surface 10a is first cleaned by the wiper 11, but at the time of this cleaning, the print head 10 is moved to a position facing the wiper 11, and the motor 20 is turned on. Rotate by a predetermined amount in a predetermined direction. The rotation of the motor 20 is transmitted to the camshaft 16, the suction source 4, and the driving gear 21 of the roller 14 via the illustrated gear system (explanation of the transmission method using the gear system is omitted), and as a result, the next operation is performed. Realized.

When the camshaft 16 begins to rotate, the contact 19a of the microswitch 19 disengages from the notch 16-2 and engages with the outer periphery of the camshaft 16, causing the solenoid 18 to stop operating and the cam 16 to stop. High part 16-1 a is protrusion 1
2a, the lever 12, biased by the spring 15, rotates to the operating position shown in FIG. 6(b), and the blade 1
1-2 comes into contact with the tip end surface 10a of the print head 10. Since the drive gear 21 also rotates at the same time as the camshaft 16 rotates, the blade 11-2 in contact with the tip surface 10a moves on the tip surface 10a as the bell eye 1-1 moves, thereby cleaning the tip surface 10a. When the motor 20 rotates a predetermined amount and stops, the tip surface 10a is completely cleaned, and the notch 16-2 of the camshaft 16 returns to its initial position (because the camshaft 16 rotates once). 'g is turned on and the solenoid 18 is activated.

Also, at this point, the cam 16-1 of the camshaft 16 is attached to the protrusion 1.
2a, the lever 12 resists the biasing force of the spring 15 and returns to the state shown in FIG.
is maintained by Since there is no need to operate the suction source 4 during the cleaning operation using the wiper 11, a clutch or the like is provided in the transmission system from the motor 20 to the pump that is the suction source 4, and by disengaging the clutch, the suction source 4
It is efficient to stop the operation of the

When purging is performed after such cleaning with the wiper 11, the print head IO is moved to a position facing the suction port 2, and the motor 20 is rotated by a predetermined amount in the same manner as described above.

Of course, in this case, the above-mentioned clutch is left on. As a result, as described above, when the camshaft 16 rotates once, the lever 12 changes from the state shown in FIG. 6(a) to the state shown in FIG. 6(b) at the initial stage.
The nozzle 10b is rotated to the state where the suction port 2 is the tip surface 10a.
Seal around the area. In this state, since the suction source 4 is operating, purging is performed by suction from the suction source 4. When the motor 20 stops, the camshaft 16 makes one revolution and stops, and the suction source 4 stops, and the lever 12 returns to its original state as shown in FIG. 5(a) and is held by the solenoid 18. be done.

Note that during this operation, a clutch or the like may be provided in the drive system of the wiper 11 to eliminate unnecessary movement of the wiper 11. At the end of this purge operation, the valve shaft 5a of the pressure release valve 5 engages with the recess 16-3 formed in the camshaft 16', and the pressure release valve 5 is activated, causing the purge chamber to be under negative pressure. is released to atmospheric pressure.

By the way, Fig. 5 shows an example in which there is one purge unit, one wiper, and one camping mechanism, but in the case of an inkjet printer that prints in color using four-color (cyan, magenta, yellow, and black) print heads, The frame 1 and the wiper 11 are arranged in four pieces so as to face each print head, and are configured to perform capping, cleaning, and purging operations on the four print heads simultaneously.

[Problem to be solved by the invention]

The problems with the conventional purge unit explained above are:
The ink sucked from each print head 10-1 to 10-4 through the resin tubes 6-1 to 6-4, respectively, is transferred to the connector 3.
After merging in the interior, it flows into the four suction sources, but in this case,
There is a possibility that the ink mixed by merging at the connecting fitting 3 may reach the nozzles of print heads of other colors due to diffusion. Further, there is a problem in that the mixed ink causes backflow due to the impact when the negative pressure inside the purge chamber is released to atmospheric pressure by the air pressure release valve 5 at the end of the purge operation.

In view of the above-mentioned problems, it is an object of the present invention to provide a purge unit that prevents the ink sucked and mixed during purging from spreading and prevents color mixture from occurring in each print head.

[Means to solve the problem]

As shown in FIG.
Each frame 1 is provided with a rubber suction port that seals around the nozzle on the tip surface of the print head 10 in accordance with the above.
-1.1-2.1-3. 1-4, a suction source 4° for suctioning ink from the front end surface of the print head 10 through a tube, etc., an air pressure release valve 5, and a suction source connected to the bottom through a tube 7 as shown in FIG. A discharge port 31b is provided, and an inflow port 31-- connected to the suction port 2 of the frame 1 through a tube 6-L6-2.6-3.64 is provided on the upper plate 31a.
1.31-2.31-'3.31-4, and a vent 31-5 connected to the pressure release valve 5 via the tube 9, each inlet 31-1.31-2.31- 3.31-4
A check valve 32 that passes only in the side direction of the discharge port 31b is provided inside the
and each inlet 31-1.31-2.31-3.3
1-4, the vent port 31-5, and the discharge port 31b are connected at the bottom to form a chamber 31 that prevents the mixed color ink from diffusing and backflowing.

[For production]

In the present invention, check valves 32 that pass only in the direction of the discharge port 31b are disposed inside the inflow ports 31-1 to 31-4, and each of the inflow ports 31-1, 31-2, 31-3. 31-4, the vent port 31-5, and the discharge port 31b are connected at the bottom for diffusion of mixed color ink.

A chamber 31 for preventing backflow is provided in each frame 1-1 to 1-1.
-4 is interposed between the suction port of the print head 4 and the suction side of the suction source 4, so when purging, the suction source 4 is activated and each print head 1
The ink sucked separately from 0-1 to 10-4 passes through the check valve 3 provided at each inlet port 31-1 to 31-4 of the chamber 31.
2 and flow separately into the bottom of the chamber 31, and the colored inks mixed at the bottom are separated by the check valve 32 into each tube 6.
It becomes possible to prevent backflow and diffusion in the -1 to 6-4 directions.

〔Example〕

The present invention will be described in detail below with reference to FIGS. 1 and 2.

Figure 1 is a perspective view of the purge unit according to this embodiment, and Figure 2 is a perspective view of the purge unit according to this embodiment.
The figure shows a sectional view of the chamber of this embodiment. In the figure, the same members as in Figure 3 are given the same symbols, and the other 31 connects each print head, pressure release valve, and suction source It is a chamber where

As shown in FIG. 2, the chamber 31 has a resin tube 6-1,6-
2.6-3. Inlet 31-1.31-2.31-3 connected to intake port 2 of frame 1 shown in FIG. 6 via 6-4
．． 31-4 and a vent 31-5 connected to the pressure release valve 5 via the resin tube 9, each inlet 31
-1.31-2.31-3.31-4 A check valve 32 is disposed inside the airtight container to allow ink to pass only in the direction toward the discharge port 31b, and each inlet port 31-1.31 -2.31
-3.31-4, the ventilation port 31-5, and the discharge port 31b are connected at the bottom of the closed container.

The configuration of the purge unit using the above chamber corresponds to print heads 10-1.10-2.10-3.10-4, which are the same as before and are unique to each color, as shown in the perspective view of Fig. 1. Each frame 1-1.12, 1-3. is provided with a rubber suction port 2 for sealing the periphery of the nozzle 10b on the tip end surface 10a of the print head 10 shown in FIG.
1-4, and a suction source 4 such as a reciprocating pump connected to the chamber 3 via a resin tube 7 or the like. and an air pressure release valve 5.

Then, the suction port 2 of each frame 1-1 to 1-4 and the inlet port 31-1.31-2.31-3.31-4 of the chamber 31
What is resin Cheaplow 1.6-2.6-3.6-4,
The vent 31-5 of the chamber 31 and the air pressure release valve 5 are connected via a resin tube 9, and the discharge port 31b and the suction side of the suction source 4 are connected via a resin tube 7. Further, the frames 1-1.1-2.13.1-4 are fixed to a lever 12 that is rotatable around the axis XX, as shown in FIG. 1-4 operation and positioning to the retreat position.

The operation of the suction source 4 and the operation of the air pressure release valve 5 are performed by means similar to conventional methods.

Note that the discharge side of the suction source 4 is connected to a drain tank (not shown) via a resin tube 8.

During purging, each print head 10-1 to 10-4 is moved to a position facing each frame 1-1 to 1-4, and the motor 20 is rotated by a predetermined amount. As a result, each frame 1-1 to 1-4 moves to the operating position, and the suction port 2 seals the periphery of the nozzle 10b of each print head 10-1 to 10-4. In addition, since the suction source 4 also operates and starts suction, the ink (and air bubbles, if any are mixed in) in the nozzles 10b of each print head 10-1 to 10-4 is removed as shown in Figure 2 ( b) As shown in the resin tube 6-
1 to 6-4 and the inlet 3 of the upper plate 31a of the chamber 31.
1-1.31-2.31-3.31-4, and the ink stored in the chamber 3 is configured to be discharged to a drainage tank.

As a result, the ink sucked from each print head 10-1 to 10-4 is transferred to each inlet port 31-1.31-2.31-3.
31-4 and flows into the bottom of the chamber 31 separately, the ink mixed at the bottom flows into each tube 6-1 to 6-6 by the check valve 32.
Since there is no backflow or diffusion in the direction 4, color mixing does not occur within the print head. Further, when the purge operation is completed, air flows into the chamber 31 by the action of the air pressure release valve 5, and when the negative pressure in each print head is released, ink of other colors does not flow back into the print head.

〔Effect of the invention〕

As is clear from the above description, the present invention has an extremely simple configuration and has advantages such as being able to prevent color mixing due to diffusion and backflow of ink sucked from the print head.
It is possible to provide a purge unit that can be expected to have significant economic and reliability effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a purge unit according to an embodiment of the present invention, FIG. 2 is a sectional view showing a chamber according to this embodiment, FIG. 3 is a perspective view showing a conventional purge unit, and FIG. 4 is a conventional purge unit. FIG. 5 is a perspective view showing the main structure of the inkjet printer, and FIG. 6 is an explanatory diagram of the purge operation. In the figure, 1-1, 1-2.1-3, 1-4 are frames, 4 is a suction source, 5 is a pressure release valve, 10-1.10-2.10-3.10-4 is a head, 3
1 is a chamber, 31a is an upper plate, 31b is an outlet, 31-1.31-2.31-3.31-4 is an inlet, 3
1-5 is a vent, 32 is a check valve, and 1-5 is a check valve.
['1ffl 3rd fig. Figure 6

Claims (1)

[Claims] Multiple print heads (10-1, 10-2,
10-3, 10-4), and the print head (10-1
, 10-2, 10-3, 10-4) from a common suction source (
4), in which the print heads (10-1, 10-
Inflow ports (31-1, 31-2, 31-3) connected to tubes (6-1, 6-2, 6-3, 6-4) that suck ink from (2, 10-3, 10-4) , 31-4) are arranged on the upper plate (31a), and each inlet (31-1, 31-2) is disposed on the upper plate (31a).
, 31-3, 31-4) are provided with a check valve (32) that allows ink to pass only in the suction direction, and a discharge port (31b) connected to the suction source (4) and each inlet port ( 31-1, 3
1-2, 31-3, 31-4) at the bottom of the sealed container, and the print head (10-1)
, 10-2, 10-3, 10-4) and the suction source (4).