JP2004181846A - Inkjet recording apparatus and recovery method for recording head thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely recover suction of both heads in an inkjet recording apparatus which has two pairs of recording heads for Y, M, C, Bk and the like, and which supplies ink from one ink tank per color to the two heads via an ink supply tube. <P>SOLUTION: The ink is sucked in by a suction cap for performing the concurrent suction of the two recording heads of the same color. Concurrently with that, the inks, which flow through tubes connected to the respective recording heads, are alternately opened/closed by a valve mechanism, so that the ink in a liquid chamber of one recording head can be prevented from flowing into the other recording head. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet recording apparatus that performs recording on a recording medium by discharging a liquid from a recording head, and a method for recovering the recording head.
[0002]
[Prior art]
In recent years, an increase in the recording speed of an ink jet recording apparatus has been increasingly required.
[0003]
As one method of increasing the speed, there is a technique of performing recording in both the forward path and the backward path of the reciprocal scanning of the head carriage.
[0004]
Further, in order to eliminate the difference in color (unevenness) between the forward printing and the backward printing, for example, two sets of printing heads that eject Y, M, C, and Bk inks are provided, and these are arranged symmetrically. A method that eliminates the difference in the order of ink ejection between the forward path and the return path is particularly suitable for speeding up.
[0005]
By the way, in order to reduce the size or the cost of the apparatus, it is preferable to provide one set of ink tanks for supplying ink to these two sets of print heads.
[0006]
Therefore, two ink supply flow paths from one ink tank to two print heads are provided for each ink color, and an ink flow path configuration connected to each print head is adopted.
[0007]
[Problems to be solved by the invention]
However, if suction recovery is performed to recover clogging or the like of the recording heads, the two recording heads are in communication with each other because ink is supplied from the same ink tank. There was a problem.
[0008]
First, when the suction recovery of only one of the print heads is to be performed, not only the flow of ink from the ink tank but also the flow of ink from the other print head to one of the print heads occurs. Ink may come off.
[0009]
In order to avoid this, if the two sets of print heads are to be suction-recovered at the same time, both print heads are caused by a fine difference in flow path resistance in the print heads and a fine difference in negative pressure generated by the suction recovery mechanism. In some cases, the ink flow is not evenly distributed, and only one of the printheads is excessively recovered, while the recovery of the other printhead remains insufficient.
[0010]
Also, as disclosed in JP-A-11-254701, when one of the ink flow paths connected to each print head is closed so that ink does not flow and only the other print head is suction-recovered, the recovery of both print heads occurs. It took twice as long to perform the recording, which hindered an increase in the total recording speed.
[0011]
[Means for Solving the Problems]
In order to solve the above problem, according to the present invention, an ink tank for storing ink to be supplied to a recording head, and ink is supplied to each of the recording heads from the ink tank to a plurality of recording heads through branched supply paths. An ink supply path, a valve mechanism for opening and closing the ink flow to each of the branched ink supply paths, a control mechanism for arbitrarily controlling the opening and closing of the valve mechanism, and a control mechanism for the plurality of recording heads. A suction recovery mechanism that simultaneously recovers suction, and simultaneously recovers the plurality of recording heads at the time of suction recovery of the print heads, and at the same time, only one valve of the valve mechanism is opened during the suction recovery operation; The opening and closing of the valve mechanisms are controlled so that all the valve mechanisms are opened at least once.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an explanatory diagram showing details of the present invention, and FIG. 2 is a schematic diagram of an ink jet recording apparatus according to the present invention. 3 to 6 are explanatory views showing the structure and operation of the ink flow path on-off valve 10. FIG.
[0013]
2, the head carriage 1 reciprocally scans in the left-right direction of the drawing by a drive mechanism (not shown) while being supported by a carriage support rail 2. Further, as shown in FIG. 1, eight recording heads Y, M, C, Bk, Bk, C, M, Y are detachably mounted by a mechanism (not shown). Each English character indicates the ink color ejected by each recording head.
[0014]
In this way, the two sets of heads are arranged so that the ejection ink colors are bilaterally symmetric so that a color difference does not occur during reciprocal printing. The print head of the embodiment has a discharge element of 1200 nozzles or more per one in order to cope with high speed, and discharges ink droplets toward a print medium based on print data such as a color image by a discharge control mechanism (not shown). . An ink tube 3 is connected to each recording head, and is supported by a mechanism (not shown) so as not to hinder reciprocal scanning of the head carriage 1.
[0015]
The other end of the ink tube 3 is connected to an ink tank 4, and supplies ink of Y, M, C, Bk colors or the like to each of the eight recording heads.
[0016]
The roll paper 5 as a recording medium is supported by the inkjet recording apparatus 6 by a support mechanism (not shown), and is transported by a transport mechanism (not shown) onto the platen 7 by a unit recording width in synchronization with the reciprocating recording operation of the head carriage. While being fed, recording is performed by the recording head.
[0017]
Next, the ink supply path and the suction recovery mechanism will be described with reference to FIG.
FIG. 1 is an explanatory diagram of the ink color Y, but the configuration is the same for the other M, C, and Bk colors.
[0018]
The Y color ink stored in the ink tank 4 is supplied to the recording head Y by the ink tube 3 which is an ink flow path. The ink tube 3 is branched into two systems at a branch part 3a in the middle, and is connected to the left and right recording heads Y, respectively. An ink flow path opening / closing valve 10 is interposed in each of the branched ink tubes 3, and an opening / closing operation is arbitrarily performed by a control mechanism (not shown) so that the inflow of ink into the recording head Y can be started or closed.
[0019]
A suction cap 20 for recovering clogging of the recording head at the home position is attached to the left and right recording heads Y so as to face each other. In addition, they are separated.
[0020]
A suction tube 21 is connected to each of the suction caps 20 facing the left and right recording heads Y. Further, the suction caps 20 are combined into a single tube at a collecting portion 21a and arranged to a tube pump 22. The tube pump 22 arbitrarily rotates clockwise by a mechanism and a control mechanism (not shown) to generate and generate a negative pressure in the tube while compressing / releasing the tube, thereby sucking ink in the recording head Y and recovering it. I do.
[0021]
Similar suction caps and tube pumps are also attached to the M, C, and Bk suction tubes, and independent of each ink color for all recording heads without moving the head carriage. At the same time, a suction operation can be performed.
[0022]
In the above configuration, at the home position, the suction cap 20 is brought into close contact with each recording head, and after closing the ink flow path opening / closing valve 10 that has allowed the ink to flow into the recording head in the open state, the tube pump 22 is stopped. When the operation is performed and the negative pressure inside the recording head Y rises, if only the ink flow path opening valve 10 of the ink tube 3 connected to one of the recording heads is opened, the flow of ink from the ink tank 4 via the recording head Y is reduced. Then, the suction recovery of one of the recording heads Y is reliably performed. In the other head, since the ink flow path opening / closing valve is kept closed, the problem that the ink inside the print head flows into one print head does not occur. Thereafter, by closing the opened ink flow path opening / closing valve and opening the other ink flow path opening valve at the same time, the suction recovery of the other recording head Y is similarly performed.
[0023]
Next, the structure of the ink flow path on-off valve 10 that operates as described above will be described.
[0024]
In FIG. 3, the ink tubes 3L and 3R branched into two at the branch portion 3a are arranged on the pressure plate 15 so as to be arranged in parallel. Each of the ink tubes 3L and 3R is a tube made of a material having the same flexibility and elasticity as the tube used for the tube pump 22, and the flow of the ink can be stopped by pressing and crushing the tube. By releasing, the ink can be restored by its own elasticity and the ink can flow again.
[0025]
Pressing levers 13L and 13R are supported on the upper surfaces of the tubes by a spring (not shown) so as to be rotatable about a rotating shaft 14 and not to apply its own weight to the ink tubes. Further, the pressing cam 11 is disposed above the pressing lever 13L, 13R so as to contact the cam contact portion 13b.
[0026]
The pressure cam 11 is fixed to a drive shaft 12, and the start and stop of rotation are freely controlled by a drive motor and a drive control mechanism (not shown).
[0027]
In addition, a cam surface is dug into the pressure cam 11 so as to escape the cam contact portions of the pressure levers 13L and 13R so as not to crush the ink tube. That is, an open cam surface 11a which is an open position through which ink can pass without crushing both ink tubes 3L and 3R, a closing cam surface 11b which crushes both of the ink tubes 3L and 3R to stop the flow of ink, and On the other hand, there are provided closing cam surfaces 11c and 11d for stopping only the flow of ink in one of the tubes. As shown in FIG. 3, these cam surfaces are arranged counterclockwise from 11a as 11b, 11c, 11b, 11d, 11b, 11c, 11b, 11d, 11b.
[0028]
FIG. 3 shows a state in which the opening cam surface 11a is on the pressure lever 13 side, and as shown in the side view of FIG. 4, both ink tubes 3L and 3R can flow ink. This is the state at the time of recording.
[0029]
When the suction recovery is started, first, the pressure cam 11 is rotated counterclockwise from the state shown in FIG. 3, and the closing cam surface 11b pushes the pressure levers 13L and 13R, and the two ink tubes 3L and 3R are moved. It is crushed and stops the flow of ink. At this point, the recovery operation of the recording head is started as described above. When the pressure cam 11 is subsequently rotated counterclockwise, only the pressure lever 13L is opened while the one-side closing cam surface 11c keeps the pressure lever 13R pressed down as shown in FIG. , The suction recovery of the recording head connected to the ink tube 3L located at.
[0030]
When the pressure cam 11 is subsequently rotated counterclockwise, the closing cam surface 11b pushes the two pressure levers 13L and 13R again, crushing the two ink tubes and temporarily stopping the suction recovery of the recording head. I do.
[0031]
When the pressurizing cam 11 is further rotated counterclockwise, as shown in FIG. 6, the one-sided cam surface 11d, which is opposite to the case shown in FIG. Since only 13R is opened, suction recovery of the recording head connected to the ink tube 3R located on the near side in the drawing is performed.
[0032]
As described above, by rotating the pressurizing cam 11 while continuously operating the tube pump 22, the two recording heads are alternately sucked and recovered as described above.
[0033]
With this configuration, while one of the recording heads is being suction-recovered, the other recording head whose ink flow has been stopped is also subjected to suction, so that the negative pressure inside the recording head increases and the pressure cam 11 When the pressure on the ink tube is released by the rotation, the ink flows into the recording head with a larger negative pressure, and a reliable suction recovery is performed.
[0034]
In the embodiment, another set of cam surfaces for performing this series of operations is provided, and one recording head receives two suction recovery operations while the pressure cam 11 makes one rotation.
[0035]
If further suction recovery is required, the pressure cam may be rotated once more while continuing the suction operation.
[0036]
It is also possible to increase the size of the pressure cam 11 and add a third set and a fourth set of cam surfaces.
[0037]
At the end of the suction recovery operation, the pressure cam 11 makes substantially one rotation, the closing cam surface 11b pushes down the two pressure levers 13L, 13R again, and both ink tubes 3L, 3R are crushed, and the ink is turned off. When the flow stops, the suction operation of the tube pump 22 is stopped, and the pressure cam 11 is continuously rotated to the position shown in FIG. 3 to return to a state where ink can flow in both ink tubes. Prepare for recording operation.
[0038]
As described above, by alternately repeating the opening and closing of the two ink flow path opening / closing valves while continuing the suction operation of the tube pump 22, the suction recovery of the recording head is more reliably performed.
[0039]
Further, in the present embodiment, the branch portion 3a of the ink tube 3 is provided in the middle of the ink tube 3, but it is needless to say that the same effect can be obtained by branching directly from the ink tank 4 into two systems.
[0040]
Further, in the present embodiment, an example in which the recording heads are independent one by one has been described. However, in the case of a recording head having a plurality of recording heads integrated and having a plurality of nozzle rows, the suction recovery mechanism may be used. It goes without saying that the cap can also be applied to a configuration in which a plurality of nozzle rows are simultaneously suctioned in accordance with the recording head.
[0041]
【The invention's effect】
A plurality of recording heads in a state where ink is communicated can be reliably suction-recovered.
[0042]
Since a plurality of recording heads can perform suction recovery during a series of suction operations of the tube pump, total recording time can be reduced.
[0043]
While one of the recording heads is being suctioned, the negative pressure is increased for the purpose of recovering the suction of the other recording head, so that a reliable suction recovery operation can be performed in a short time.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an operation of suction recovery according to the present invention. FIG. 2 is an explanatory diagram of an ink jet recording apparatus according to the present invention. FIG. 3 is an explanatory diagram of an ink flow path opening / closing valve according to the present invention. FIG. 5 is an explanatory view of an ink flow path opening / closing valve according to the present invention. FIG. 6 is an explanatory view of an ink flow path opening / closing valve according to the present invention.
DESCRIPTION OF SYMBOLS 1 Head carriage 2 Carriage support rail 3 Ink tube 4 Ink tank 6 Ink jet recording device 10 Ink channel opening / closing valve 11 Pressure cams 13L, 13R Pressure lever 20 Suction cap 22 Tube pump

Claims (2)

An ink jet recording apparatus that forms an image by ejecting ink from a recording head to a recording medium,
An ink tank for storing ink to be supplied to the recording head,
An ink supply path for supplying ink to each of the printheads by a branched supply path from the ink tank to a plurality of printheads;
A valve mechanism for opening and closing the flow of ink in each of the branched ink supply paths,
A control mechanism for arbitrarily opening and closing the valve mechanisms,
A suction recovery mechanism for simultaneously recovering the plurality of recording heads by suction recovery.
At the same time as the suction recovery of the plurality of print heads at the time of suction recovery of the print head,
An ink jet recording apparatus for controlling opening and closing of a valve mechanism such that only one of the valve mechanisms is opened and all valve mechanisms are opened at least once during a suction recovery operation. And a method for recovering the recording head. 2. An ink jet recording apparatus, wherein the mechanism according to claim 1 is provided for each ink color provided to support color recording.

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