JP2003039689A - Inkjet recording device - Google Patents

Abstract

(57) [Object] To provide an ink jet recording apparatus capable of increasing the viscosity of ink at the tip of a nozzle which causes clogging and thereby recovering clogging of the nozzle. When an orifice plate surface is wiped by a wiping blade, a voltage is continuously applied to an energy generating member so that ink droplets protrude from the orifice plate surface at substantially the same time.

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 for recording by driving an energy generating member in response to a recording signal and ejecting ink droplets from a nozzle, and more particularly to a method for recovering nozzle ejection.

[0002]

2. Description of the Related Art An ink jet recording apparatus carries out recording by ejecting ink droplets onto recording paper from nozzle openings of a recording head which will be described in detail below.

FIG. 3 is a sectional view of the recording head. The recording head 1 is provided with a plurality of nozzles 2 for ejecting ink droplets, a pressure chamber 3 communicating with each nozzle, an energy generating member 4 provided for each pressure chamber, and fluctuating the pressure of the pressure chamber 3, each pressure chamber 3 And a common ink chamber 6 that communicates with the restrictor 5 through the restrictor 5.
Is driven to change the pressure in the pressure chamber 3 to eject ink from the opening of the nozzle 2, and ink is supplied to the common ink chamber 6 from an ink cartridge (not shown) or the like at any time.

In such a recording head, if the ink is not ejected for a while, the volatile component (mainly water) of the ink evaporates from the opening of the nozzle 2 which is open to the atmosphere, and the ink is dried and thickened. Therefore, there is a problem that the nozzle is clogged. In order to cope with such a problem, in a conventional ink jet recording apparatus, the head is sealed with a cap member made of an elastic material such as rubber when no recording is performed. However, since the cap member directly contacts the ink surface at the tip of the nozzle (hereinafter referred to as the meniscus) to prevent foreign matter from entering the nozzle and destroying the meniscus when the cap is opened, the orifice of the recording head is closed even when the head is sealed. A space is provided between the plate surface and the cap member, and moisture evaporates from each nozzle tip portion immediately after capping until the space reaches the saturated vapor pressure.

If the ink is left in the capping state for a long time, the ink at the tip of the nozzle exposed to the atmosphere will be dried due to the slight gap between the recording head and the cap member and the air permeability of the tube, and clogging will occur. There is no fundamental solution, such as the occurrence. Therefore, in the conventional ink jet recording apparatus, a so-called purging operation is performed when the power is turned on or when necessary to perform a nozzle recovery operation.
Next, an example of a conventional nozzle recovery operation will be described with reference to FIG. The purging operation for discharging the thickened ink to the outside of the recording head will be described with reference to FIG. A cap member 7 is provided outside the recording area and is made of an elastic material such as rubber for capping the recording head 1. When the purging operation is performed, the recording unit 9 including the recording head 1 and the ink cartridge 8 that supplies ink to the recording head 1 moves to a position above the cap member 7, and the cap member 7 is raised by a power source (not shown). The recording head 1 is capped. In many cases, the inside of the cap is designed to facilitate suction during ink suction and to moisten the atmosphere inside the cap.
An ink absorption sheet 10 is provided. Further, two tubes 11 and 12 are connected to the bottom surface of the cap member 7, and the tube 11 is connected to the atmosphere release valve 13. The tube 12 can supply a negative pressure to the inside of the cap via the suction pump 14, and the ink in the recording head 1 is sucked by closing the atmosphere opening valve 13, and the space 15 in the cap is opened by opening the atmosphere opening valve 13. Ink the ink that has collected. The sucked ink is discharged to an ink discharge chamber 16 provided at the tip of the tube 12. After the ink is sucked from the recording head 1, the space 15 in the cap is filled with the ink, and the orifice plate surface 17 of the recording head is naturally contaminated with the ink. 17 need cleaning.

Next, cleaning of the orifice plate surface will be described with reference to FIG. A wiping blade 18 made of an elastic material such as rubber is disposed between the cap member 7 and the recording area. The wiping blade 18 is held by a blade holder 19 and is located on the moving path of the orifice plate surface 17 of the recording unit 9. It is structured so that it can move forward and backward. After the purging operation is completed, the wiping blade 18 is moved along with the blade holder 19 onto the orifice plate surface movement path of the recording unit by a drive source (not shown), and the wiping blade 18 moves the orifice plate surface 17 along with the reciprocating movement of the recording unit 9.
Wipe off and clean.

Further, in the print head of an on-demand ink jet printer, ink is not always ejected from individual nozzles during a printing operation, and depending on the print pattern, nozzles with non-driving time of the order of several minutes occur. I have something to do. For this reason, the ink at the tip of the non-driving nozzle continues to be exposed to the atmosphere, the ink thickens due to drying, and a solid film is formed on the surface of the meniscus. As a result, when a driving pulse is suddenly applied to a nozzle having a long non-driving time, normal ejection cannot be performed and printing failure occurs. Therefore, conventionally, during the recording operation, tens to several hundreds of ejections are periodically performed from all the nozzles on the cap or on the ink drop receiver provided in the non-recording area regardless of recording. A so-called refresh operation is performed to discard the thickened ink.

[0008]

However, when performing such a purging operation or a refreshing operation, a large amount of ink is required at one time, and the discharged ink is wasted, so that the economy is poor. There is.

Further, since the orifice plate surface of the recording head is contaminated with ink by performing the purging operation, a so-called wiping operation for cleaning the orifice plate surface is further required after the purging operation, which causes a problem of poor time efficiency.

An object of the present invention is to provide a method for recovering the thickening of ink at the nozzle tip, which causes clogging, and the clogging of the nozzle.

Another object of the present invention is to provide a recovery method capable of reducing the amount of ink to be discarded when recovering the thickened ink in the nozzles and making the ink consumption efficient. .

Another object of the present invention is to provide a recovery method capable of shortening the time required to recover the thickened ink in the nozzle.

[0013]

The above-mentioned object is to perform recording by driving an energy generating member in response to a recording signal and ejecting an ink droplet from a nozzle opening.
A wiping blade that is movable relative to the recording head so as to wipe the orifice plate surface of the recording head, and wipes the orifice plate surface with a wiping member at the time of recovery of a defective ejection nozzle caused by ink drying or thickening. At the same time, the voltage is continuously applied to the energy generating member to the extent that the meniscus protrudes from the surface of the orifice plate. Further, it is achieved by wiping the surface of the orifice plate and at the same time applying a drive pulse signal to the energy generating member to the extent that the meniscus protrudes from the surface of the orifice plate.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a front view of the ink jet recording apparatus of the present invention, and the hatched portion is a sectional view. The recording head, the cap member, and the wiping member have the same configurations as those of the conventional technique described above, and therefore the same reference numerals are used.

A recording unit 9 having the recording head 1 and an ink cartridge 8 for supplying ink to the recording head 1 is slidably supported on a guide shaft 20 and connected to a power transmission member 21. The drive source 22 reciprocates along the guide shaft 20. On the other hand, the recording medium 23 faces the orifice plate surface 17 of the recording head 1 and is conveyed by a conveying roller 24 in a direction orthogonal to the moving direction of the recording unit 9. Ink is ejected from the nozzles 2 of the recording head 1 to the recording medium 23 in accordance with a recording signal to form an image.

A recording head 1 is provided outside the recording area.
Is a cap member made of an elastic body such as rubber for capping. At the time of non-recording, the recording unit 9 moves to a position above the cap member 7 provided in the non-recording area, and the cap member 7 caps the recording head 1 by a power source (not shown) so that the ink in the recording head is as much as possible. To prevent dryness. An ink absorbing sheet 10 may be provided in the cap for facilitating suction at the time of sucking ink and for moistening the atmosphere in the cap. Further, two tubes 11 and 12 are connected to the bottom surface of the cap member 7, and the tube 11 is connected to the atmosphere release valve 13. The tube 12 can supply a negative pressure to the inside of the cap via the suction pump 14, and by closing the atmosphere opening valve 13, it is possible to initially fill the recording head 1 with ink.
The ink accumulated in the space 15 in the cap is sucked by opening 3. The waste ink is discharged to a waste ink chamber 16 provided at the tip of the tube 12.

A wiping blade 18 made of an elastic material such as rubber is arranged between the cap member 7 and the recording area. The wiping blade 18 is a blade holder 19
Is held in the orifice plate surface 17 so that the orifice plate surface 17 can move back and forth along the moving path. When a wiping operation is required, the wiping blade 18 is moved to a movement path of the orifice plate surface 17 of the recording unit 9 by a driving source (not shown), and the orifice plate surface 17 is cleaned as the recording unit 9 reciprocates.

The removal operation of the thickened ink according to the present invention will be described with reference to FIG. When printing starts (step
S101) The elapsed time t from the start of printing is counted in the print control unit (not shown) (step S10).
2) If the time exceeds s (for example, 10 seconds) when the print head finishes printing for m scans (step S1)
04; Yes) The recording operation is interrupted (step S105), and the recording unit 9 starts moving in the direction in which the wiping blade 18 is provided (step S106). Almost at the same time, the wiping blade 18 is moved by a drive source (not shown) onto the movement path of the orifice plate surface 17 of the recording head 1 (step S107). When the recording head 1 passes through the wiping blade 18 and the orifice plate surface 17 is wiped by the wiping blade, the nozzles 2 of the recording head 1 are compressed in the pressure chamber 3 (direction in which ink is ejected). A constant voltage is continuously applied to the energy generating member 4 so that the ink slightly protrudes from each nozzle 2 (step S108). As a result, the recording head 1 passes the wiping blade 18, is wiped by the wiping blade 18, and at the same time, the thickened ink slightly protruding from the opening of the nozzle 2 can be scraped off.

Further, when the recording head 1 returns to the printing area (step S109), the wiping blade 18 is also similarly used.
By wiping the surface 17 of the orifice plate, it is possible to reliably scrape off the thickened ink (step
S110). Also, instead of applying the constant voltage,
Wiping may be performed while applying a drive pulse at several kHz to several tens of kHz so that the ink may protrude from the orifice plate surface 17. After the wiping operation, the wiping blade 18 is retracted from the moving path of the orifice plate surface 17 by a driving source (not shown) (step S1.
11), t is reset and recording is restarted (step S1).
12). When recording is completed (step S103; No), several tens of ink droplets are deposited on the cap to moisten the space inside the cap.
After performing a refresh operation of ejecting several hundreds of ejections (step S113), the recording head 1 is capped by the cap member 7 (step S114). During printing, the paper dust generated from the recording paper may adhere to the opening of the nozzle 2 of the recording head 1 and cause ejection failure. However, by performing the above operation, the orifice plate surface 17 is regularly formed.
Is wiped, dust such as paper dust can be removed, and reliability regarding print quality is improved.

Further, by providing the monitoring means for the driving nozzles and the non-driving nozzles during recording, it is possible to optimally control the timing of performing the wiping according to the non-driving time of the non-driving nozzles.

Next, the ejection failure nozzle recovery operation when printing is not performed for a long time continues will be described with reference to the flowchart of FIG. When the power ON is received (step S201), the recording head 1 is released from the cap member 7 (step S202), and the recording head 1 starts moving in the recording area direction (step S203). Almost at the same time, the wiping blade 18 is moved by a drive source (not shown) onto the movement path of the orifice plate surface 17 of the recording head 1 (step S204). The recording head 1 passes through the wiping blade 18, wipes the orifice plate surface 17 with the wiping blade 18, and at the same time, applies the same voltage as described above so that the ink slightly protrudes from each nozzle (step S205). After that, the recording head 1 moves toward the wiping blade 18 (step S206), and performs the same operation when returning to the cap position (step S207). Next, the ejection confirmation of the ink droplets is carried out by the ink droplet ejection detection means portion (not shown) provided in the non-recording area (step S208).
Here, if there is a non-ejection nozzle or a nozzle whose ejection speed is slower than the normal ink ejection speed (step S
209; Yes), the wiping operation is executed again.
When there is a nozzle that does not recover even after performing the wiping operation n times (preferably about 1 to 3) (step S21)
0; Yes), the wiping blade 18 is retracted from the movement path of the orifice plate surface 17 by a drive source (not shown) (step S211), and the recording head 1 is capped by the cap member 7 (step S212). The ejection failure nozzle is recovered by the purging operation (step S213). After the ejection failure nozzle recovery operation by the purging operation, or after the ejection failure nozzle recovery operation according to the present invention, no abnormality is found in the ink droplets as confirmed by the ink droplet ejection detection unit (step S
209; No), if there is a recording command (step S214;
Yes) Recording is started (step S216), and the recording operation described in the flowchart of FIG. 1 is executed (step S2).
17). If there is no recording command, the recording head 1 is capped and stands by (step S215).

[0022]

According to the present invention, since only the ink whose viscosity has increased at the nozzle tip can be discharged to the outside of the recording head, it is possible to minimize the amount of discharged ink required for the nozzle recovery operation, which is economical. An inkjet recording device can be provided. In addition, since defective ejection nozzles are prevented by performing wiping periodically or when necessary during the recording operation, it is possible to remove dust and the like, and it is possible to provide an inkjet recording apparatus with high print quality reliability. Further, the nozzle can be recovered without performing the purging operation, and the time-efficient inkjet recording apparatus can be provided.

[Brief description of drawings]

FIG. 1 is a flow chart for performing the operation of the present invention.

FIG. 2 is a flowchart for executing the operation of the present invention.

FIG. 3 is a sectional view of a recording head.

FIG. 4 is an explanatory diagram illustrating a conventional nozzle recovery operation.

FIG. 5 is a schematic front view of an inkjet recording apparatus.

[Explanation of symbols]

1 ... Recording head, 2 ... Nozzle, 4 ... Energy generating member,
17 ... Orifice plate surface, 18 ... Wiping blade.

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Claims (7)

[Claims] 1. A recording head for recording by driving an energy generating member in response to a recording signal to eject ink droplets from a plurality of nozzle openings provided in the orifice plate, and an orifice plate surface of the recording head. In an inkjet recording head equipped with a wiping blade capable of moving relative to the recording head so as to be wiped,
An ink jet recording apparatus, characterized in that a voltage is continuously applied to the energy generating member to such an extent that an ink droplet protrudes from the orifice plate surface almost at the same time as the wiping blade wipes the orifice plate surface. 2. A recording head for recording by driving an energy generating member in response to a recording signal to eject ink droplets from a plurality of nozzle openings provided in the orifice plate, and an orifice plate surface of the recording head. In an inkjet recording head equipped with a wiping blade capable of moving relative to the recording head so as to be wiped,
An ink jet recording apparatus, wherein a drive pulse signal is applied to the energy generating member to the extent that ink droplets protrude from the orifice plate surface almost at the same time as the wiping blade wipes the orifice plate surface. 3. A recording head for recording by driving an energy generating member in response to a recording signal to eject ink droplets from a plurality of nozzle openings provided in the orifice plate, and an orifice plate surface of the recording head. In an inkjet recording head equipped with a wiping blade capable of moving relative to the recording head so as to be wiped,
An inkjet recording apparatus, wherein any one of claims 1 and 2 is periodically executed during execution of the recording operation. 4. A recording head for recording by driving an energy generating member in response to a recording signal to eject ink droplets from a plurality of nozzle openings provided in the orifice plate, and an orifice plate surface of the recording head. An inkjet recording head comprising a wiping blade capable of moving relative to the recording head so as to be wiped, and a means for monitoring the ejecting nozzles, according to a non-driving time of a non-driving nozzle during execution of a recording operation. Or 2
An inkjet recording apparatus, characterized by performing any one of the operations described. 5. A recording head for performing recording by driving an energy generating member in response to a recording signal to eject ink droplets from a plurality of nozzle openings provided in the orifice plate, and an orifice plate surface of the recording head. The inkjet recording head having a wiping blade capable of moving relative to the recording head so as to be wiped and a means for detecting ejection of an ink droplet, when the abnormality of the ink droplet is detected, the operation according to claim 1 or 2. An ink jet recording apparatus characterized by carrying out. 6. A recording head for performing recording by driving an energy generating member in response to a recording signal to eject ink droplets from a plurality of nozzle openings provided in the orifice plate, and an orifice plate surface of the recording head. An ink jet recording head provided with a wiping blade capable of moving relative to the recording head so as to be wiped, and a means for detecting ejection of ink droplets. An ink jet recording apparatus, characterized in that the operation of any one of claims 1 and 2 is further performed when an ejection check is performed and an abnormality of an ink droplet is detected. 7. A recording head for recording by driving an energy generating member in response to a recording signal to eject ink droplets from a plurality of nozzle openings provided in the orifice plate, and an orifice plate surface of the recording head. A wiping blade that can move relative to the recording head so as to be wiped, and a cap member that seals the recording head so as to cover the nozzle opening of the recording head and is supplied with a negative pressure from a suction pump and discharge of ink droplets. In an ink jet recording head equipped with a means for detecting the above, the ejection of ink droplets is confirmed after performing the operation of any one of claims 1 and 2 once or several times, and when an abnormality of the ink droplets is detected, The recording head is sealed by a cap member and the suction pump is driven to drive the nozzle opening. Ink jet recording apparatus characterized by sucking the ink.