JPH08174855A - Ink jet recording device - Google Patents

Abstract

PURPOSE: To provide an ink jet recording device wherein a pigment is used as, a recording ink, a protective liquid is stored as measures for preventing clogging, and prevent a coagulating component in the recording ink from remaining in an orifice by the protective liquid after completion of printing. CONSTITUTION: In a record head, a recording ink 33 and a protective liquid 36 are stored in an ink cartridge which is separated by a partition having a membrane filter 34 at a part. A solenoid valve 35 for the recording ink and a solenoid valve 37 for the protective liquid are arranged in front of a passage 30 to a nozzle orifice. Further, a dummy hole and a passage 300 for the dummy are provided for supplying the protective liquid from the front face of the record head when a recording nozzle is clogged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to a printer having a clogging recovery function,
The present invention relates to a printing device such as a copier and an OA information device incorporating the printing device.

[0002]

2. Description of the Related Art Most inks used in ink jet recording apparatuses use a water-soluble dye as a coloring material. This is because one of the factors is that the water-soluble dye is promptly redissolved in water, which is a solvent, to prevent nozzle clogging and to easily remove and redissolve aggregates.

Japanese Patent Laid-Open No. 61-185451 discloses a device provided with a means for capping the nozzle and filling the inside of the cap with a protective liquid as a measure for preventing clogging of the nozzle. The overall structure of this apparatus is as shown in FIG. 11, and has a head 1 for printing and a mechanism 2 for preventing clogging of nozzles.

A mechanism for preventing nozzle clogging is as shown in FIG. 12. When the power is turned off, the pump unit 10 draws a vacuum in the cap 5, and the valve 24 is opened to pass the protective liquid through the nozzle. Installed on the front of 2 to prevent drying. Further, when air is mixed in the nozzle, it is sucked and removed under negative pressure.

On the other hand, although there is an apparatus using a pigment-dispersed ink for recording, this apparatus has a mechanism in which the head itself is disposable, and when an unrecoverable failure due to clogging occurs, it is called a head conversion by a user. It's a simple task.

[0006]

The pigment-dispersed ink is superior in water resistance and light resistance to the water-based dye ink, and has less bleeding on plain paper.
Once dried and solidified, the original state will not be restored even if the solvent is added, and the nozzle orifice will be clogged.

In the above-mentioned device, the pigment-dispersed ink can be used by making the head a disposable structure, but the cost of the device and the running cost are high.
Further, if a means for filling the inside of the cap with a protective liquid is provided as in the device disclosed in Japanese Patent Application Laid-Open No. 61-185451, the cost of the device increases and the size and complexity of the entire device increase.

According to the present invention, a pigment is used as the recording ink, a protective liquid is stored as a measure for preventing clogging, and the protective liquid is used after the printing is completed so that the coagulation component of the recording ink does not remain in the orifice portion. It is an object of the present invention to provide an inkjet recording device that does.

[0009]

According to the present invention, the above-mentioned object is an ink jet recording apparatus for ejecting a recording ink in which pigment particles are dispersed in a solvent from a nozzle to perform recording. The recording apparatus according to claim 1, further comprising: a storage unit that stores a protective liquid for the nozzle containing a water-soluble dye ink, and a supply unit that supplies the protective liquid to the nozzle.

According to the present invention, the above-mentioned object is characterized in that the supply means includes a valve for switching and supplying the recording ink or the protective liquid to the nozzle inside the recording head. This is achieved by the recording device described in 2.

According to the present invention, the above-mentioned object is achieved by a recording apparatus according to claim 3, wherein the storage means comprises a filter means that allows only the solvent of the recording ink to pass through.

According to the present invention, there is provided the recording apparatus according to claim 4, wherein the storage means is an ink cartridge integrally formed with a partition of the recording ink and the protective liquid. To be achieved.

According to the present invention, the above-mentioned object is achieved by a recording apparatus according to claim 5, further comprising a dummy hole on the front surface of the nozzle, the dummy hole communicating with the supply means.

[0014]

In the ink jet recording apparatus according to the present invention, the liquid supplied to the nozzle of the recording head when the power switch is turned off by the supply means is switched from the recording ink to the protective liquid, and the protective liquid is supplied from the nozzle. Can be jetted. This spray leaves the protective liquid in the nozzle orifice,
In addition to the solvent, a water-soluble organic solvent such as glycol can be mixed as a component of the protective liquid as a drying inhibitor, and the protective liquid can remain as a viscous liquid even when drying proceeds. This prevents the pigment ink from coagulating and clogging the nozzles to make printing impossible. Further, in the next use, after the power is turned on and before the printing is started, the recording ink is similarly ejected, and then the printing is performed, whereby the printing can be smoothly performed.

In the ink jet recording apparatus according to the second aspect, the valve for switching the liquid to be supplied to the nozzle can facilitate selection of two kinds of liquid, the recording ink and the protective liquid, to supply to the nozzle. Further, since the valve is provided inside the recording head, it is possible to reduce the amount ejected from the nozzle when the power switch is turned on / off.

In the ink jet recording apparatus according to the third aspect of the present invention, a filter that allows only the solvent of the recording ink to pass through even when the protective liquid is insufficient, such as when the power is turned on / off frequently and the printing amount is small, for example Thus, only the solvent can be replenished from the recording liquid to the protective liquid.

In the ink jet recording apparatus according to the fourth aspect, the protective liquid is simultaneously replaced and replenished when the recording ink is emptied by the ink cartridge having the partition between the recording ink and the protective liquid. As a result, the user need not be aware of the replacement and replenishment of the protective liquid.

According to the ink jet recording apparatus of the fifth aspect, the dummy liquid communicating with the supply means provided on the front surface of the nozzle sucks the protective liquid under negative pressure even when the nozzle is clogged due to drying. The nozzle can be pulled out to the front of the nozzle, and the clogging of the nozzle can be eliminated.

[0019]

Embodiments of the ink jet recording apparatus of the present invention will be described below with reference to the drawings.

FIG. 6 shows a schematic configuration of the printing unit according to the embodiment of the present invention.
Shown in A recording head 64 that performs printing and an ink cartridge 61 that supplies ink to the recording head 64 are arranged on a carriage 62 that moves left and right by a motor.
A platen 63 for bringing the head into close contact with the printing paper at the time of printing and a cap 65 for housing and protecting the nozzles of the recording head 64 after the printing is arranged on the frame on the side facing the recording head.

As for the appearance of the recording head 64, as shown in FIG. 1, the ink receiving portion 12 and the nozzle main body 11 are combined, and the ink receiving portion 12 is provided with a hole 13 for passing a wiring to the solenoid valve. The nozzle body 11 is provided with a plurality of nozzle orifices 10 for ejecting recording ink and protective liquid and a plurality of dummy nozzles 14 for ejecting protective liquid.

The cross section of the recording head 64 in the vertical direction is as shown in FIG. 2, and the position before the ink is branched to the plurality of nozzles 20 in the middle of the ink flow path in the head shown by the diagonal lines in the drawing. Is provided with two electromagnetic valves 24, and the liquid supplied to the nozzle 20 is switched by the electromagnetic valves 24.
Also, the horizontal cross section is as shown in FIG.
As in FIG. 2, the diagonal lines in the figure show the ink flow paths.
The recording ink 33 and the protective liquid 36 are separated on the upstream side of the electromagnetic valves 35 and 37, but a membrane filter 34 is provided on a part of the partition wall. In this embodiment, a membrane filter made of polysulfone and having a filtration diameter of 0.1 μm is used.

As shown in FIG. 4, the cartridge is provided with a porous body 39 corresponding to each of the recording ink and the protective liquid, and the space between them is partitioned. The head is engaged with the porous body 39 (urethane foam) and the stainless mesh 31 shown in FIG. 3, and the recording ink and the protective liquid are not mixed with each other, and the supply port 38 is provided on the front surface.
Will be supplied from.

As the recording ink, a pigment ink in which the weight% of each component has the following composition is used.

-Ion-exchanged water ... 75-Colorant: carbon black. Average particle size 0.2 μm …… 5 ・ Thermoplastic resin: Polyacrylic acid …… 5 ・ Water-soluble organic solvent: Ethylene glycol …… 15 ・ Dispersant (nonionic surfactant) …… 0.1 For recording with this composition Ink is particularly excellent in terms of water resistance, light resistance, and little bleeding on printed matter, but after the nozzle is exposed to drying for a long time, clogging occurs, and negative pressure suction from the front of the orifice, wiping, etc. The solidified material cannot be removed completely.

On the other hand, as a protective liquid, an aqueous dye ink is used in which the weight% of each component is the following composition.

・ Ion-exchanged water ・ ・ ・ 80 ・ Water-soluble dye: CI Direct Black 19 ・ ・ ・ 5 ・ Water-soluble organic solvent: ethylene glycol …… 12 ・ Water-soluble organic solvent: butanol) ・ ・ ・ 3 ・ Surfactant …… 0.1 The ink having this composition is inferior to the above pigment ink in the water resistance and the light resistance of the printed matter, but has the moisturizing property and the re-dissolving property even after being dried, and the clogging is easily caused by the suction of the negative pressure from the front surface of the orifice. Can be removed.

The operation of this embodiment will be described below with reference to the drawings.

The flow of the operation when the power switch is turned on will be described with reference to FIGS. 8 and 3. First, the cap 44 covering the front surface of the head is opened until the power switch is turned on (S81). After confirming that the head is at the home position (S82), open the solenoid valve 35,
The electromagnetic valve 37 is closed and the recording ink 33 is supplied to the flow path 30 (S83). Then, the recording ink is applied to the cap 44.
It is jetted into the inside for a fixed time (10 seconds) (S84), and the protective liquid remaining in the pressure chamber and the orifice portion is replaced with the recording ink, and the print preparation is completed. During printing, the recording ink 33 is supplied to the nozzles through the flow path 30.

The flow when printing is completed and the power switch is turned off will be described with reference to FIGS. 9 and 3.
In this case, the device detects that the power switch is turned off, performs the following processing, and then shuts off the power line. First, return the print head to the home position (S9
1), the electromagnetic valve 35 is closed, the electromagnetic valve 37 is opened, and the protective liquid 36 is supplied to the flow path 30 (S92). After that, the protective liquid is sprayed toward the cap 44 for a fixed time (10 seconds) (S93). As a result, the recording ink remaining in the pressure chamber and the orifice portion is replaced with the protective liquid. After the injection is completed, the cap 44 is closed (S94), the power relay is turned off (S95), and the process is completed.

The nozzle used had the structure shown in FIG.
The piezoelectric element 41 is deformed by the applied drive pulse 43, and this deformation causes the vibration plate 42 to be in close contact with the piezoelectric element 41.
Is deformed, and pressure is applied to the ink indicated by the diagonal lines in the figure to eject a droplet from the orifice 40. This nozzle is provided with a plurality of dummy nozzles 14 having an orifice diameter of 50 μm and communicating with the flow path of the protective liquid shown in FIG. When using the nozzle having such a structure, instead of the injection operation in S83 of FIG. 8 and S93 of FIG. 9, the cap 44 shown in FIG.
It is also possible to replace it by an operation of opening the cap 44 after suctioning a negative pressure for about 2 seconds to fill the inside of the cap with ink or a protective liquid.

Further, by using this dummy nozzle, it is possible to perform a recovery process when clogging occurs. The clogging recovery process is performed as follows according to the flow shown in FIG.

At the start of printing, when it is confirmed by the operator that clogging has occurred and an instruction to perform a recovery operation is given, the head moves to the home position (S101). Next, the cap 44 is closed (S102), the electromagnetic valve 35 shown in FIG. 3 is closed, the electromagnetic valve 37 is opened, and the protective liquid 36 is supplied to the flow path 300 (S103). Then, the suction pump is operated for 5 seconds (S104), and the inside of the cap is negatively sucked by the suction port 46 to fill the inside of the cap with the protection liquid, and then the ultrasonic generator (piezoelectric vibrator) attached to the cap. An ultrasonic wave is generated for 60 seconds by 45 to remove the solidified material of the recording ink remaining in the clogged printing nozzle orifice 40 (S105).
After the removal is completed, the suction pump is operated for a certain time to discharge the liquid filled in the cap (S106),
The liquid in the cap is discharged from the suction port 46, and the cap 4
4 is opened (S107). Solenoid valve 35 for print preparation
Is opened, the electromagnetic valve 37 is closed, the recording ink 33 is supplied to the flow path 30 (S108), preliminary ejection is performed for 3 seconds from the nozzle (S109), and the process is completed.

In this embodiment, an electromagnetic valve is used as a means for switching the liquid to be supplied, but a valve actuating mechanism using an operating force for pressing the carriage against the home position side frame and a spring restoring force may be used. An example of this mechanism is shown in FIG.
Will be described with reference to. FIG. 7 is a partially enlarged view of the head portion 64 of FIG. 6 and the side frame of the apparatus. Reference numeral 71 shows the side frame, and the other portions show the structure for controlling the liquid supplied inside the head. In the printing state, as shown in the drawing, the protection liquid valve head 75 closes the protection liquid supply tube 73 by the force of the spring 77, and the recording ink is supplied from the tube 74. When printing ends and the head moves to the home position, the valve lever 72 is pushed against the side frame 71, the tube 74 is closed by the ink valve head 76, and the protective liquid valve head 75 is moved by the seesaw 78 to the protective liquid supply tube 73.
The protective liquid is supplied away from the. When the supply of the protective liquid is stopped, it is only necessary to move the recording head from the home position by the required distance.

[0035]

According to the ink jet recording apparatus of the first aspect of the invention, clogging can be prevented without leaving a solidification component in the orifice. This facilitates maintenance of the nozzle and improves reliability. Furthermore, by using a water-based dye ink of the same color as the protective liquid, it is possible to prevent a decrease in density and save the amount and time of non-printing jetting.

According to the ink jet recording apparatus of the second aspect, the amount of ink replacement is small, and the time and the amount of non-printing jetting when the power is turned on / off can be saved.

According to the ink jet recording apparatus of the third aspect, the solvent is replenished from the recording ink through the filter even in a use environment in which the printing amount is small and the power source is frequently turned on / off. The clogging prevention operation can be performed.

According to the ink jet recording apparatus of the fourth aspect, by using the cartridge in which the recording ink and the protective liquid are integrated, the user can easily handle the protective liquid.

According to the ink jet recording apparatus of the fifth aspect, it becomes possible to suck the protective liquid through the dummy hole into the cap and ultrasonically clean the printing nozzle. Thus, even if the recording nozzle is clogged due to an erroneous operation, it can be recovered by performing ultrasonic cleaning, and the reliability of the apparatus is enhanced.

[Brief description of drawings]

FIG. 1 is a diagram showing an outer appearance of a recording head of an embodiment of a recording apparatus of the present invention.

FIG. 2 is a vertical cross-sectional view of the recording head of the embodiment of FIG.

FIG. 3 is a horizontal cross-sectional view of the recording head of the embodiment of FIG.

FIG. 4 is a view showing the structure of the cartridge of the embodiment of FIG.

5 is a diagram showing the structure of a nozzle and a cap of the embodiment of FIG.

FIG. 6 is a diagram showing a schematic configuration of a printing unit of the embodiment of the recording apparatus of the present invention.

FIG. 7 is a diagram showing a configuration that replaces the solenoid valve of the embodiment of FIG.

FIG. 8 is a diagram showing a flow of operations at the time of power-on of the embodiment of FIG.

FIG. 9 is a diagram showing a flow of operations when the power of the embodiment of FIG. 1 is turned off.

10 is a diagram showing a flow of a clogging recovery operation by the nozzle of FIG.

FIG. 11 is a diagram showing an entire conventional inkjet recording apparatus.

FIG. 12 is a diagram showing a clogging recovery mechanism of a conventional inkjet recording apparatus.

[Explanation of symbols]

 10, 20, 40 Nozzle orifice 11 Nozzle body 12 Ink receiving part 13 Solenoid valve lead hole 14 Dummy nozzle 21, 31 Stainless steel mesh 22, 32, 39 Porous body 23, 33 Recording ink 24, 35 Recording ink electromagnetic valve 25 valve seat 30 recording ink flow path 34 membrane filter 36 protective liquid 37 protective liquid solenoid valve 38 cartridge mating part 300 protective liquid flow path 41 piezoelectric element 42 diaphragm 43 drive pulse 44 cap 45 ultrasonic generator 46 negative pressure Suction port

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Claims (5)

[Claims] 1. An ink jet recording apparatus for performing recording by ejecting a recording ink in which pigment particles are dispersed in a solvent from a nozzle, and a storage means for storing a protective liquid for the nozzle containing a solvent or a water-soluble dye ink. And a supply unit that supplies the protective liquid to the nozzle. 2. The recording apparatus according to claim 1, wherein the supply unit includes a valve for switching and supplying the recording ink or the protective liquid to the nozzle inside the recording head. 3. The recording apparatus according to claim 1, wherein the storage unit includes a filter unit that allows only a solvent of the recording ink to pass therethrough. 4. The recording apparatus according to claim 1, wherein the storage unit is an integrally formed ink cartridge including a partition for the recording ink and the protective liquid. 5. The recording apparatus according to claim 1, further comprising a dummy hole on the front surface of the nozzle, the dummy hole communicating with the supply unit.