JPH04216063A - Ink injection method - Google Patents

Abstract

PURPOSE:To prevent the color mixture due to the back flow of the ink from a cap or an ink discharge pipe by a simple structure in the supply of ink to the ink sub-tank of an ink jet recording apparatus. CONSTITUTION:When ink is injected in an ink sub-tank at the time of the replacement of a printing head, an ink discharge solenoid valve 20 is opened. The ink is simultaneously sucked from the ink discharge port 12 of the ink sub-tank 13 and the ink sump 18 of a cap member 10 by a suction pump 6 and injected in the ink sub-tank 13 through an ink supply pipe 19 and an ink supply port 11. When the ink is injected in the ink sub-tank 13, the ink discharge solenoid valve 20 is closed and the backflow of the ink discharged from the ink sump 18 to the ink sub-tank 13 is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink injection method for an ink jet recording apparatus having a sub-ink tank.

0002

2. Description of the Related Art Inkjet recording apparatuses perform maintenance such as capping, purging, priming, and wiping when not printing in order to prevent ejection failure or non-ejection due to drying of the nozzle surface or adhesion of dust.

FIG. 4 is a schematic configuration diagram for explaining an example of a maintenance mechanism. In the figure, 1 is a maintenance device, 2 is a print head, 3 is an atmospheric release solenoid valve, 4 is an atmospheric pressure supply pipe, 5 is an ink discharge pipe, 6 is a suction pump, 7 is an ink waste tank, 8 is a cap rubber, 9 is wiper, 1
0 is a cap member, 11 is an ink supply port, 12 is an ink discharge port, 13 is a sub-ink tank, and 14 is a carriage. The print head 2 is a head compatible with four colors of ink, for example, 2b is black, 2c is cyan, 2m
is magenta, and 2y is yellow.

The maintenance mechanism 1 is mounted on a carriage 14 and moves the cap member 10 forward with respect to the print head 2 positioned at a maintenance position to bring the cap rubber 8 into close contact with the print head 2, or
The position of the cap member is controlled so that the cap member 10 is moved back to release the cap rubber from the close contact state, or the cap member 10 is placed in an intermediate position to be in a semi-released state, and maintenance operations are performed. have them do it.

[0005] The above-mentioned maintenance operation will be explained. Capping is an operation in which the maintenance mechanism moves forward to bring the cap rubber 8 into close contact with the print head 2, thereby preventing the nozzle portion from drying out and preventing the ink viscosity from increasing.

[0006] Purging is an operation in which the cap member 10 is released or semi-released from the print head 2, and a print signal is applied to the print head to cause the print head to eject ink, thereby discharging the thickened ink.

Priming is an operation in which the suction pump 6 is operated to suck thickened ink from the nozzle with the cap in place.

In wiping, the cap member 10 is partially released from the print head 2, the tip of the wiper 9 is brought into contact with the surface of the print head 2, and the carriage 14 is moved to wipe the nozzle surface with the wiper 9. This operation is like wiping off.

FIG. 5 is a perspective view of the print head 2 viewed diagonally from the rear. In the figure, 11 is an ink supply port, 12 is an ink discharge port, 13 is a sub-ink tank, 15 is a connector,
16 is a printed circuit board. Further, the dotted arrow indicates the trajectory of the ejected ink droplet. A sub-ink tank 13 attached to the print head 2 is used to alleviate ink pressure fluctuations caused by movement of the carriage and improve refilling. The ink supply port 11 of the sub-ink tank 13 is connected to an ink supply tube (not shown). The ink discharge port 12 is provided to supply ink to the sub-ink tank 13 and to remove air bubbles mixed in the ink.

FIG. 6 is a schematic diagram for explaining a situation in which ink is automatically injected into the print head 2 as shown in FIG. 5 using the maintenance mechanism 1 as shown in FIG. 4. In the figure, parts similar to those in FIGS. 4 and 5 are designated by the same reference numerals, and explanations thereof will be omitted. 17 is an ink tank, 18 is an ink reservoir, and 19 is an ink supply pipe. Ink reservoir 18
are the print heads 2b, 2c, 2m of each color explained in FIG.
, 2y, 18b is black, 18c
corresponds to the cyan head, 18m corresponds to magenta, and 18y corresponds to yellow.

[0011] To supply ink to the sub-ink tank 13, suction is performed from the ink discharge port 12.
Ink from the ink tank 17 is sucked from the ink supply port 11 through the ink supply pipe 19. Ink discharge port 12
When the ink is suctioned, not only the ink supply port 11 is suctioned, but also the nozzle is suctioned. When a nozzle is suctioned, ink is injected through the ink reservoir 18 corresponding to the nozzle.
The ink is sucked in, and even the ink inside the ink discharge tube 5 is sucked in. Since ink of each color is mixed in the ink discharge tube 5, there is a problem that color mixing occurs.

Therefore, in the past, the head 2 was moved from the carriage.
was removed and the nozzle was closed with a shielding member (not shown), ink was sucked from the ink discharge port 12, and the ink was manually injected into the sub-ink tank 13. This method is very time-consuming and has the problem that ink drips easily and stains the device.

[0013] In addition, in the case where the ink can be injected automatically without removing the head 2, the ink can be injected between the ink reservoirs 18b, 18c, 18m, 18y of each color and the ink discharge pipe 5 (position A in the figure). In order to prevent color mixing, the structure was complicated and the cost was high.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an inkjet recording device with a simple structure that eliminates color mixing due to backflow of ink from the cap and ink discharge tube. It is an object of the present invention to provide an ink supply method that can supply ink to a sub-ink tank.

[0015]

[Means for Solving the Problems] The present invention provides a method for injecting ink into a sub-ink tank in an inkjet recording apparatus, which includes, when injecting ink into the sub-ink tank from an ink supply port, suction of ink from an ink discharge port; It is characterized by simultaneously suctioning ink from the cap side.

Ink suction from the cap side may be performed by a maintenance device that protects the nozzle and restores ejection.

[0017]

[Operation] When injecting ink into a sub-ink tank in an ink jet recording apparatus from an ink supply port, ink is sucked from the ink supply port by suctioning from the ink discharge port of the sub-tank. In this case, negative pressure is created on the nozzle side of the print head.

In the present invention, by also suctioning ink from the cap side when suctioning from the ink discharge port, it is possible to prevent the nozzle from suctioning ink from the ink discharge pipe side. Therefore, color mixing does not occur during ink injection.

[0019]

[Embodiment] In the present invention, for example, the carriage 14
When performing color printing by attaching four print heads 2b, 2c, 2m, and 2y to the printer, a small, high-performance maintenance station as shown in FIG. 4 can be used.

FIG. 1 is a schematic diagram of a maintenance device used in an embodiment of the present invention, in which a cap member is in close contact with a print head. In the figure, parts similar to those in FIG. 6 are denoted by the same reference numerals, and explanations thereof will be omitted. 20, which is not provided in FIG. 6, is an ink discharge solenoid valve.

[0021] This maintenance device includes capping,
It has wiping, priming, and purging functions. The outline of each of these functions will be explained with reference to FIGS. 1 and 4.

In the initial state, the head 2 is capped. At this time, the carriage 14 and the maintenance device 1 are in opposing positions, and the nozzle surface of the head 2 on the carriage 14 and the cap rubber 8 attached to the cap member 10 are in close contact. An opening is formed in the cap rubber 8 at a position facing the nozzle,
It communicates with the opening of the ink reservoir 18.

[0023] When printing is performed, the cap member 10 is released. The release is performed by moving the cap member 10 to the opposite side of the carriage 14 using a motor, cam, etc. (not shown). Then, as shown in FIG. 3, the carriage 14 is moved left and right along the guide shaft 22 by the carriage motor 24 and belt 23, and the platen 2
1. Print on the recording paper above.

When printing is not performed, the carriage 14 is moved to face the maintenance device 1, and the cap member 10 is advanced as in the initial state, so that the nozzle surface of the print head 2 is stuck to the cap member 10. The device waits in a state where it is in contact with the cap rubber 8.

Even during printing, there may be nozzles that do not eject continuously depending on the printing pattern. In a nozzle that does not eject, the viscosity of ink within the nozzle increases, resulting in non-ejection or poor printing directionality the next time printing is performed. For this reason, the carriage 14 is moved to the home position, which is the position facing the maintenance device 1, once every 10 to 20 scans.
Perform purging.

The purging operation is performed by discharging ink into the ink reservoir 18 of the cap member 10. The number of ejections is preferably 10 to 100 drops from each nozzle, and it is preferable to set the frequency lower and drive energy higher (drive voltage, pulse width) than the drive conditions for normal printing. Ink reservoir 1
The ink discharged into the ink tank 8 is sucked by the suction pump 6 with the ink discharge electromagnetic valve 20 closed, and then transferred to the ink waste liquid tank 7.
to be discharged.

If ink adheres to the nozzle surface of the print head 2 during printing, an ink film will be formed and the ink will no longer be ejected. Therefore, the carriage 14 is moved to the home position once every 10 to 20 scans, and the cap member 10 is brought into a semi-released state by a drive source (not shown). Thereafter, the carriage 14 is moved left and right by the carriage motor 23, and a wiping operation is performed to wipe off the ink on the nozzle surface using the wiper 9 formed integrally with the cap rubber 8.

The moving distance of the carriage 14 during wiping is set so that the print head moves to a position midway between an adjacent wiper and the next wiper. When printing is to be continued after wiping, the cap member 10 is released.

When printing is started or when printing is not performed for a while after being capped, the viscosity of ink in the nozzles of the head 2 increases even though the nozzles are capped, and the next printing is likely to become unstable. Therefore, priming is performed. Priming is performed by sucking ink from the nozzle with the suction pump 6 while the ink discharge solenoid valve 20 is closed.
The ink is discharged into the ink waste liquid tank 7. The reason why the ink discharge solenoid valve 20 is kept closed is so that the ink in the sub-ink tank 13 is not discharged through the ink discharge port 12.

The above is an outline of the maintenance operation in the maintenance device 1.

Next, the operation of injecting ink into the sub-ink tank 13 using the maintenance device 1 will be explained.

When injecting ink into the sub-ink tank 13 of the print head 2, such as when replacing the print head, the ink discharge solenoid valve 20 is kept open and the suction pump 6 is used to fill the sub-ink tank 13 of the print head 2. Ink is simultaneously sucked from the ink discharge port 12 and the ink reservoir 18 of the cap member 10, and the ink is injected from the ink tank 17 into the sub-ink tank 13 through the ink supply port 11 via the ink supply pipe 19. Ink suction time is 2-5
When ink is injected into the sub-ink tank 13 in seconds,
The ink discharge solenoid valve 20 is closed to prevent the ink discharged from the ink reservoir 18 from flowing back into the sub-ink tank 13.

Note that the ink tank 17 and the ink supply pipe 1
9. The ink discharge solenoid valve 20 is provided independently for each color, and a part of the ink discharge pipe 5 connected from the ink discharge port 12 to the suction pump 6 is also provided independently for each color.
It is connected to two suction pumps 6.

In FIG. 1, during priming, the ink discharge solenoid valve 20 was closed and ink was sucked from the nozzle by the suction pump 6. However, when air bubbles enter the upper part of the sub-ink tank 13 due to movement of the carriage, etc., the suction pump 6 is driven with the ink discharge solenoid valve 20 open, and the air bubbles are suctioned and removed through the ink discharge port 12. can be done.

Injecting ink into the sub-ink tank 13,
In any case of removing air bubbles in the sub-ink tank 13,
The suction pressure and suction time may be changed depending on the flow path resistance.

FIG. 2 is a schematic configuration diagram for explaining an embodiment using a maintenance device that can change the suction pressure and suction time between the nozzle side and the ink discharge port side. In the figure, parts similar to those in FIG. 1 are denoted by the same reference numerals, and explanations thereof will be omitted.

In this embodiment, the suction pumps connected to the ink discharge pipe 5a connected to the ink discharge port 12 of the sub-ink tank 13 and the ink discharge pipe 5b for sucking from the nozzle have different characteristics. a suction pump 6a with
, 6b. The suction time can be changed by changing the opening time of the ink discharge solenoid valve 20.

[0038]

As is clear from the above description, according to the present invention, ink can be injected into the sub-ink tank using a maintenance device with a simple configuration, and air bubbles are not mixed in from the nozzle when ink is injected. Without further ado,
In the case of a color print head, the print head can be left attached to the carriage without ink contamination.
This has the effect of automatically injecting ink into the sub-ink tank.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a maintenance device used in an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a maintenance device used in another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an example of a carriage drive mechanism.

FIG. 4 is a schematic configuration diagram for explaining an example of a maintenance device.

FIG. 5 is a perspective view of an example of a print head.

FIG. 6 is a schematic configuration diagram of a conventional maintenance device.

[Explanation of symbols]

1 Maintenance device 2 Print head 5 Ink discharge pipe 6 Suction pump 7 Ink waste tank 8 Cap rubber 9 Wiper 10 Cap member 11 Ink supply port 12 Ink discharge port 13 Sub ink tank 14 Carriage 17 Ink tank 18 Ink reservoir 19 Ink supply pipe

Claims (1)

[Claims] Claim 1: In a method for injecting ink into a sub-ink tank in an inkjet recording device, when injecting ink into the sub-ink tank from an ink supply port, ink suction from an ink discharge port and ink suction from a cap side are simultaneously performed. An ink injection method characterized by: