JP2803665B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head having a plurality of rows of ejection nozzles for ejecting ink droplets, and a cap for sucking ink from the ejection nozzles in order to eliminate clogging of the ejection nozzles. It relates to a recording device.

[0002]

2. Description of the Related Art An ink jet recording apparatus provided with an ink jet head for ejecting ink droplets from an ejection nozzle in response to a print signal, cannot perform printing if paper dust or ink residue adheres to the ejection nozzle and causes clogging. Become. For this reason, a cleaning device is provided that seals the surface of the inkjet head on which the ejection nozzles are formed with a cap, and applies a negative pressure of a suction pump to the cap to forcibly discharge ink from the ejection nozzles to the cap. .

[0003]

However, when the number of rows of ejection nozzles constituting an ink jet head increases for high-density recording, high-speed recording, force recording, or the like, the number of rows increases.
As the size of the cap constituting the cleaning device increases, the space volume of the cap rapidly increases, and the suction capacity of the pump relatively decreases. As a result, the cleaning becomes incomplete or necessary. The time for sucking the ink amount becomes longer. If the suction capacity is increased in order to solve such a problem, there is a problem that the size of the pump increases, the number of housings accommodating the pump increases, and the size of the entire recording apparatus increases. Further, in the ink jet head for color printing, the inks of the adjacent ejection nozzles that eject inks of different colors at the time of suction mix and meet, and the mixed ink adheres to the ejection nozzles and causes color mixing at the time of printing. There is a problem.

Further, in the case of sealing with a large cap, a delicate movement is required to obtain a completely sealed state, and it takes time until the capping is completed. In particular, in cleaning during printing, the printing speed is reduced. There is a problem of causing a decrease. The present invention has been made in view of such a problem, and an object of the present invention is to efficiently mix an inkjet head having multiple rows of ejection nozzles with ink of another adjacent ejection nozzle row. Without causing
Another object of the present invention is to provide an ink jet recording apparatus capable of performing cleaning while minimizing a decrease in printing throughput.

[0005]

According to the present invention, there is provided an ink-jet head having an ejection nozzle which is divided into a plurality of portions in a width direction of a recording sheet, and includes an ink jet head having a plurality of ejection nozzles. a first cap portion of the injection nozzle only has a size that can be sealed, and placed outside the printing area of a suction pump for supplying a negative pressure to the first cap, at the time of cleaning the ink jet head Moved and divided into the plurality
Only a part of the spray nozzle is selectively sealed by the first cap, and the cleaning is performed by applying a negative pressure from the suction pump. In addition, when no printing is performed, the inkjet head is sealed by the second cap. I made it.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 shows an embodiment of an ink jet recording apparatus according to the present invention, in which a carriage 11 is mounted with an ink jet head 12 to be described later, and is guided by a guide shaft 13 to drive a pulse motor or a DC servo motor (not shown). By the forward and reverse rotation, the recording paper 14 reciprocates in the width direction of the recording paper 14 fed in the direction shown by the arrow D by the paper feeding means (not shown). The position of the carriage 11 is constantly managed by an encoder (not shown) based on the position detected by the position detector 15.

As shown in FIG. 2, the print head 12 has a plurality of rows of spray nozzles 23, 23, 23,..., And in this embodiment, six rows, and two adjacent rows are displaced in the paper feeding direction. Are arranged in a staggered pattern. These six rows of ejection nozzles 23, 23, 23,... Are divided into three blocks A, B, and C in units of two rows, and are configured to be able to eject different inks, respectively. Thus, high resolution can be realized by arranging the ejection nozzles 23, 23, 23,... In a staggered manner, and by arranging a plurality of blocks in the width direction of the recording paper.

[0008] The ink jet head 12 is a tube 1
6, the ink tank 1 is connected to the ink tank 1.
The printing is executed by receiving the supply of the ink from the printer. Recording paper 14
Outside, i.e., in the non-printing area, a cap 17 connected to a suction pump 18 by a tube 22 is provided.
The cap 17 has a cavity 24 on a surface corresponding to the ejection nozzle 23 of the inkjet head 12 and is configured as a rubber container having a size that can individually seal each of the blocks A, B, and C of the inkjet head 12. It is attached to a cap solenoid 27 which moves forward and backward against a spring force in a direction perpendicular to the ink jet head surface. Outside the cap 17 (on the left side in the figure), all blocks A of the ink jet head at the time of printing suspension,
A protection cap 26 for sealing B and C in the same space is provided.

The cap 17 accommodates a porous member 25 for absorbing ink in a cavity 24 and a solenoid 21.
Is connected via a tube 22 to a valve 20 which is opened and closed by the valve and connected to the suction pump 18 via a tube 48.

The operation of the above-configured device will be described with reference to FIGS. 3 and 4. When the cleaning signal is output, the cap solenoid 27 and the valve solenoid 21 are energized. As a result, the cap 17 is retracted from the movement trajectory of the inkjet head 12 against the spring force, and is communicated with the atmosphere via the valve 20.

In this state, the carriage 11 moves the ink jet head 12 in the direction of the cap 17 and stops at a position where a specific block, for example, the block A faces the cap 17. Next, when the cap solenoid 27 is deactivated, the cap 17 is moved to the ink jet head 1.
Only the second block A is sealed, the valve solenoid 21 is deenergized, and only the ejection nozzle 23 of the block A of the inkjet head 12 is sealed by the cap 17 as shown in FIG. Of course, since the cap 17 is smaller in size than the protective cap 26, airtightness with the ink jet head 12 can be easily ensured, and a sealed state can be secured in a shorter time than sealing with the protective cap 26.

When the suction pump 18 operates in this state,
The negative pressure of the suction pump 18 acts only on the injection nozzles 23 constituting the block A of the inkjet head 12,
The ink is supplied from the ejection nozzle 23 of the block A to the cap 17.
In this process, bubbles in the flow path constituting the inkjet head 12 and the injection nozzles 23 of the block A.
Paper dust and ink residue adhering to are discharged to the cap 17 together with the ink.

[0013] The suction operation of the thus broke off communication with the atmosphere for a predetermined time, after continuing for example a few seconds, the cap 17 to bias the valve sono laid 21 again when the communication with the atmosphere, the ink The ink adhered to the nozzle surface in the suction step, the ink accumulated in the cap 17 and further the ink adhered to the cap 17 are discharged to the waste ink tank 19 along with the flow of air flowing through the valve 20. You. Finally, when the suction pump 18 is stopped and the cap 17 returns to the atmospheric pressure, the cap solenoid 27
The carriage 11 is moved to the position where the next block of the inkjet head 12, for example, the block B, faces the cap 17 while the cap 17 is separated from the head 12 and the valve 20 is opened.

When the above-described steps are repeated in this state, the nozzle opening 23 of the block B of the ink jet head 12 is sealed with the cap 17, and is cleaned in the same manner as the ejection nozzle 23 of the above-mentioned A block (FIG. 3 (II)). ).
Similarly, when the cleaning of the ejection nozzles 23 of the block B is completed, the carriage 11 is moved to seal the block C of the inkjet head 12 with the cap 17 (FIG. 3 (III)), and the cleaning is executed.

In this manner, the ink jet head 12
When the cleaning is completed, if the print command is not output, the carriage 11 is further moved to the non-printing area side (the left side in the figure) to seal the inkjet head 12 with the protective cap 26, and Block A,
Drying of the B and C injection nozzles 23 and adhesion of dust are prevented (FIG. 3 (IV)).

Since a plurality of injection nozzles are sealed by the single cap 26 in this manner, the moisturizing effect is high, and the time until clogging can be extended.

On the other hand, when the print command is output, the carriage 11 moves to the print area side, and the ink jet head 12 ejects ink droplets from the ejection nozzles 23 to execute printing on the recording paper 14.

As described above, since the cap 17 is disposed closer to the printing area than the protective cap having a high moisturizing effect, during cleaning during the printing period, the cap 17 is moved to the printing area after the cleaning is completed. It is possible to improve the printing speed by shortening the distance as much as possible.

FIG. 5 shows another embodiment of the ink jet head in the form of an array of jet nozzles. In this embodiment, the jet nozzles 23, 23, 23,. Blocks Y, C,
M and B are divided into nozzle openings 23 of each block.
Are configured to be able to eject yellow, cyan, magenta, and black ink droplets.

FIG. 6 shows an embodiment of an ink jet recording apparatus using the above-described ink jet head. In this embodiment, four blocks Y, C, M and B of the ink jet head 12 are used. And a cleaning switch 30 for independently commanding cleaning.

In this embodiment, if, for example, disturbance or chipping is found in magenta printing, the cleaning circuit (M) of this block M is operated, and the control circuit 31 causes the block M of the ink jet head 12 to turn off the cap. The carriage 11 is moved to a position opposing the block 17, and only the block M is sealed with the cap 17 in the same sequence as described above to perform cleaning.

When cleaning the jet nozzles of the blocks of two or more colors, the switch 30 for designating the block requiring cleaning is simultaneously set to two.
Individual or continuous pressing operation.

At this stage, when the suction of ink from one block is completed, the valve 20 is opened and the cap 1 is opened.
When the suction is further performed in a state where the cap 17 is separated from the ink jet head 12 in addition to discharging the ink to the waste ink tank 19 with the air in a state where the ink jet head 7 is communicated with the atmosphere, the edge of the cap 17 and the ink jet head 1
The ink adhering to the nozzle surface of No. 2 can be reliably sucked into the cap 17 to prevent the ink from scattering or dripping when moving to the next block, and without causing color mixing when the next block is sealed. Block can be cleaned.

Also, since only blocks requiring cleaning can be sealed with the cap, ink can be selectively discharged only from the jet nozzles requiring cleaning without accompanying discharge of ink from the jet nozzles requiring no cleaning. Cleaning can be performed without waste of ink.

[0025]

As described above, in the present invention,
An inkjet head having an injection nozzle which is arranged in a plurality in the width direction of the recording paper, one of the injection nozzle
Only injection nozzle parts to have a size that can be sealed, and a first cap disposed outside the printing area, and a suction pump for supplying a negative pressure to the first cap to move the ink jet head during cleaning Split and distribute
Only a part of the placed spray nozzle is selectively sealed by the first cap, cleaning is performed by applying a negative pressure from the suction pump, and the inkjet head is sealed by the second cap during non-printing. In spite of the use of multiple nozzles for high-speed printing, high-resolution printing, and color printing, ink can be sucked using a small cap compared to an inkjet head, so the cap is small because it has a small volume. The suction pump can also efficiently suction ink and selectively suction the ejection nozzles that require cleaning, reducing the time required for head cleaning and eliminating the discharge of ink from the ejection nozzles that do not require cleaning. Ink can be prevented from being wasted. Only the ejection nozzles can be independently suctioned to completely prevent color mixing due to mixing of ink in the cap. Furthermore, the miniaturization of the cap ensures that the inkjet head is sealed in a short time The distance between the printing area and the cleaning area can be shortened, the movement of the carriage for the cleaning operation during printing can be shortened, and these can be combined to increase the printing speed. Has the effect of

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of an ink jet recording apparatus according to the present invention.

FIG. 2 is a view showing an embodiment of an ink jet head used in an ink jet recording apparatus according to the present invention in the form of an arrangement of ejection nozzles.

FIGS. 3 (I) to (IV) are explanatory views showing the operation of the above ink jet recording apparatus.

FIGS. 4A to 4D are timing charts showing a cleaning operation of the ink jet recording apparatus.

FIG. 5 is a view showing another embodiment of the ink jet head used in the ink jet recording apparatus of the present invention in the form of nozzles.

FIG. 6 is a diagram showing another embodiment of the ink jet recording apparatus suitable for the ink jet head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink tank 11 Carriage 12 Ink jet head 15 Carriage position detector 17 Cap 18 Suction pump 19 Waste ink tank 20 Valve 21 Valve solenoid 23 Nozzle 26 Protection cap 27 Cap solenoid 30 Cleaning switch 31 Control circuit

Claims (4)

(57) [Claims] And 1. A ink jet head having an injection nozzle which is arranged by dividing into multiple in the width direction of the recording paper, said
It has a size that can be sealed portion of the injection nozzle only of the injection nozzle, and a first cap disposed outside the printing area, and a suction pump for supplying a negative pressure to the first cap, at the time of cleaning The inkjet head is moved so that one of the injection nozzles divided and
Only the part is selectively sealed by the first cap, and cleaning is performed by applying a negative pressure from the suction pump,
An ink jet recording apparatus for sealing the ink jet head with a second cap during non-printing. 2. The second cap is less marked than the first cap.
2. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is arranged on a printing area side . 3. A print head comprising a plurality of second caps,
2. A size having a size capable of sealing an injection nozzle in an area.
3. The ink jet recording apparatus according to claim 1. 4. An injection nozzle having a different color in each of the areas.
Ink droplets and perform the cleaning operation.
Specifying means for selecting the area to be
If cleaning is specified, cleaning of one area
At the end of the charging, the first cap is communicated with the atmosphere.
After suction by the suction pump, the next area is closed.
The ink jet according to claim 1, wherein the cleaning is performed.
Recording device.