JP2002234195A - Method of cleaning print head for ink jet printer and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of cleaning a print head capable of preventing defective printing or deterioration in printing quality due to ink adhered to a nozzle-formed face of the print head. SOLUTION: In this method of cleaning the print head, ink is sucked by an ink sucking pump in order to discharge the ink having the increased viscosity in an ink supply passage in a condition that the print head is capped. A rubbing/ wiping operation is executed to wipe the ink adhered to the nozzle-formed face of the print head in the ink-sucking operation. After that, a carriage is reciprocated predetermined number of times in a predetermined range in a condition that the print head is not driven. As the residual ink on the nozzle- formed face is moved to an ink nozzle position by the vibration of the carriage, the ink is allowed to enter the ink nozzle in a negative pressure in a normal condition to be removed therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer which performs printing by discharging ink droplets from a plurality of ink nozzles onto recording paper, and more particularly to a technique for cleaning a nozzle forming surface of a print head. .

[0002]

2. Description of the Related Art In general, an ink jet printer discharges ink droplets from ink nozzles of a print head while reciprocating a carriage on which a print head is mounted within a predetermined range, thereby printing characters and images on recording paper. Form.

During non-printing, the carriage waits at a predetermined position (home position) outside the printing range. In the standby state, the nozzle forming surface of the print head is covered with a cap in order to prevent thickening of the ink in the ink nozzles and intrusion of bubbles from outside. Also, the ink suction pump is driven to periodically suck the ink from the ink nozzles while the nozzle forming surface is covered with the cap, so that the thickened ink and air bubbles are discharged to the outside. In addition, foreign substances such as paper dust and ink adhered to the nozzle forming surface are wiped by, for example, a blade made of an elastic material.

[0004]

However, in the process of sucking ink from the ink nozzles as described above, the ink adheres to the nozzle forming surface, and the adhered ink falls on the recording paper or in the paper path to perform recording. There was a problem of soiling the paper. Also, during the printing process, due to the movement of the carriage, the attached ink on the nozzle forming surface moves to the periphery of the ink nozzle and blocks a part of the ink nozzle, thereby distorting the ejection path and possibly impairing print quality. was there. Therefore, after the ink suction process, a process of wiping the nozzle forming surface has been performed.

However, in the process of wiping the nozzle forming surface of the print head, paper foreign matters adhering to the wiping member may be pushed into the ink nozzles, thereby destroying the ink surface (meniscus) in the nozzles. This causes a so-called dot omission, which causes printing failure.

In order to avoid such a problem, foreign matter is discharged by performing a preliminary ejection process of ejecting ink droplets from all the ink nozzles into the cap after performing a wiping process on the nozzle forming surface. Although a method is conceivable, it was insufficient to discharge all foreign substances.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art. It is an object of the present invention to provide a printing method and a printing quality which are caused by foreign matter adhering to a nozzle forming surface of a print head. It is an object of the present invention to provide a print head cleaning method for an ink-jet printer which can prevent a decrease in the print quality.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a print head cleaning method for an ink jet printer which prints on recording paper by moving a carriage having a print head for discharging ink droplets. In the method, after (a) sucking ink from the ink nozzle of the print head, and (b) after step (a),
And a step of reciprocating a carriage.

In the case of the present invention, the ink particles adhering to the nozzle forming surface can be sucked into the ink nozzle by simply reciprocating the print head in a negative pressure state. As a result, it is possible not only to prevent printing defects due to missing dots caused by ink particles attached to the nozzle surface, but also to prevent deterioration in printing quality due to distortion of the ejection path of ink droplets to be printed. .

In this case, it is preferable that the carriage is reciprocated a predetermined number of times. Further, it is preferable that the printing head is reciprocated within a predetermined range (for example, a printing range). If the number of reciprocating movements is large, the amount of ink movement on the nozzle forming surface increases, and if the range of reciprocating movement is wide, the carriage can move at high speed, so that the ink on the nozzle forming surface moves easily, and Becomes easy to be drawn into the ink nozzle, and it becomes possible to eliminate all of the ink regardless of the position of the ink attached on the nozzle surface.

[0011] The present invention also relates to a computer readable information recording medium having recorded thereon a program for executing the print head cleaning method.

In this case, the information recording medium is a compact disk, a floppy disk, a hard disk, a magneto-optical disk, a digital video disk,
It may include a magnetic tape, a semiconductor memory, and a memory device.

The present invention also relates to an ink jet printer for printing on recording paper by moving a carriage on which a print head for discharging ink droplets is mounted, and an ink suction pump for sucking ink from ink nozzles of the print head. A control unit that controls the ink jet printer, the control unit drives an ink suction pump to suck ink from the ink nozzles, and a carriage after sucking ink by the ink suction pump. A carriage driving means for reciprocating movement.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an ink jet printer and a print head cleaning method according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a printer according to the present embodiment. As shown in FIG. 1, the inkjet printer 1 includes a print head mechanism 10, an ink cartridge 20, a head maintenance unit 30, and a control unit 40.

The print head mechanism 10 has a print head 11 mounted on a carriage, and a carriage motor 12 for driving the carriage. A carriage on which the print head 11 is mounted is movably supported by a carriage shaft 13 extending in the width direction of a predetermined paper path, and the power of the carriage motor 12 (for example, a stepping motor) is transmitted via gears or the like (not shown). It is configured to be transmitted. As a result, the print head 11 moves in the directions indicated by arrows A and B.
Can be reciprocated in the directions shown in FIG.

The ink cartridge 20 contains a flexible ink pack 21 and a waste ink absorbing material 2 inside a hard case.
2 is stored. An ink supply tube 2 is provided in an ink supply port 24 formed in the ink pack 21.
One end of 3 is connected via an ink supply needle. The other end of the ink supply tube 23 is connected to the print head 11.
It is connected to the.

On the nozzle forming surface 15 of the print head 11,
A plurality of ink nozzles 14 capable of discharging ink droplets are formed. Further, inside the print head 11, an ink chamber 16 communicating with each nozzle 14 is provided, and a predetermined amount of ink from the ink supply tube 23 is stored. The bottom wall of the ink chamber 16 is formed to be thin so as to function as a vertically displaceable diaphragm in FIG. Then, by applying a predetermined voltage to the diaphragm,
The nozzle 14 is configured to discharge ink droplets. For stable printing, the ink supply pressure from the ink pack 21 to the print head 11 is always kept at a negative pressure, and a meniscus is formed in the nozzles 14. The nozzle forming surface 15 of the print head 11 is subjected to a water-repellent treatment.

Here, as shown in FIG. 1, a head maintenance unit 30 is disposed at a position facing the home position of the carriage set at the end in the direction of arrow B. The head maintenance unit 30 includes an ink suction pump 32 that suctions and discharges the thickened ink and residual air bubbles and the like in the ink supply path from the nozzles 14 of the print head 11, and paper powder and ink attached to the nozzle forming surface 15. And a cleaning lever 31 for wiping off foreign matter. The home position is head cap 3
3 is the position where the nozzle forming surface of the print head 11 is capped. The head cap 33 is formed in a substantially box shape large enough to cover the nozzle forming surface 15 of the print head 11, and is arranged at a predetermined interval from the nozzle forming surface 15.

The ink suction pump 32 is mainly connected to a waste ink absorbing material 22 for absorbing the sucked ink, one end of which is connected to the waste ink absorbing material 22 and the other end of which is connected to a head cap 33 for capping the nozzle 14. A flexible ink tube 35, a roller (not shown) that rolls while crushing the ink tube, and a pump motor 34 for rolling the roller. Then, the roller is rolled and the head cap 3 of the ink tube 35 is rotated.
By setting the side communicating with 3 with a negative pressure, ink is sucked from the nozzles 14 of the print head 11.

The cleaning lever 31 is a long member, and has a tip portion provided with a wiping portion 31c in which a plate-like rubber material 31a and a felt material 31b are bonded. Further, the cleaning lever 31 is connected to the pump motor 3.
By transmitting the power of No. 4 via gears or the like (not shown), the print head 11 is configured to be movable in directions of arrows C and D substantially perpendicular to the nozzle forming surface 15 of the print head 11. As a result, the wiping portion 31c of the cleaning lever 31 can reciprocate between an advanced position where it can contact the nozzle forming surface 15 of the print head 11 and a retracted position where it does not.

FIG. 2 is a block diagram of a control system relating to print head maintenance of the printer 1. As shown in FIG. 2, the control unit 40 of the printer 1 includes a flushing unit 41, a print head reciprocating unit 42, and a wiping / rubbing unit 43 for maintaining the print head 11.
And The control unit 40 is electrically connected to the carriage motor 12 and the pump motor 34, respectively, so that the units 41 to 43 perform the functions described below.

The flushing means 41 functions to drive and control the carriage motor 12 to position the print head 11 at the home position, and to control the application of a voltage to the print head 11 so that ink is ejected from all the nozzles 14 a predetermined number of times. have.

The print head reciprocating means 42 has a function of driving and controlling the carriage motor 12 to reciprocate the print head 11 a predetermined number of times within a predetermined range (for example, within a printing range) after the flushing is completed. I have.

Further, wiping / rubbing means 43
Controls the driving of the pump motor 34 so that the wiping portion 31c of the cleaning lever 31 is moved to the nozzle surface 15 of the print head 11.
The print head 11 has a function of moving the print head 11 a predetermined number of times outside the printing range including the position where the carriage motor 12 is in contact with the wiping unit 31c by driving the carriage motor 12 to a position where the print head 11 can be brought into contact with the wiping unit 31c.

Next, the cleaning process of the printer 1 will be described. FIG. 3 is a flowchart showing the flow of the cleaning process, and FIGS.
FIG. 3 is a diagram showing a state of a nozzle forming surface 15 of FIG.

First, ink remaining in the ink supply path is sucked by the ink suction pump 32 (step S1). As shown in FIG. 4, the ink liquid adheres to the nozzle forming surface 15 of the print head 11 after the ink suction process over a wide range.

In step 2, a wiping / rubbing process is performed to wipe off the ink attached to the nozzle forming surface 14 of the print head 11 by the ink suction process. Here, as shown in FIG. 5A, the rubber member 31a of the wiping portion 31c of the cleaning lever 31 wipes the ink on the nozzle forming surface 15 with respect to the print head 11 moving in the direction of arrow B. As shown in FIG. 5B, the print head 11 moving in the direction of arrow A is
The felt member 31b of the wiping portion 31c of the cleaning lever 31 rubs the ink on the nozzle forming surface 15. Even after this processing, a part of the ink adhering to the nozzle forming surface 15 is converted into a nozzle 9 by the water repellency of the nozzle forming surface 15 and the surface tension of the ink liquid as shown in FIG. It may remain on the surface 15.

As described above, in the wiping / rubbing process, the ink adhering to the nozzle forming surface 15 is wiped. At this time, the thickened ink or the like may be pushed into the nozzle 14. Therefore, in step S3, the ink chamber 1 of the print head 11 is again operated by the ink pump 21.
The ink in 6 is sucked. Even if the thickened ink is pushed into the nozzle 14 in the process of step S2, the thickened ink is in the vicinity of the nozzle 14, so if the ink stored in the ink chamber 16 is sucked, it is discharged. Because you can.

Thereafter, in step S4, a flushing process for discharging ink from all the nozzles 14 of the print head 11 into the head cap 33 is performed. This flushing process is performed to form an ink meniscus, discharge minute bubbles, and prevent color mixing in a multicolor printer. By this flushing process, the number of ink particles 9 on the nozzle forming surface 15 may be reduced to two or three as shown in FIG.

In step 6, the carriage motor 12 is driven and controlled, and the print head 11 is reciprocated a predetermined number of times in the directions of arrows A and B. As a result, FIG.
As shown in FIG. 9, the ink particles 9 attached to the nozzle forming surface 15 move on the nozzle surface 15 in a direction opposite to the moving direction of the print head 11 and come into contact with the nozzle 14. And is eliminated from the nozzle forming surface 15.

In this case, it is necessary to set the number of reciprocating movements of the print head 11 to the number of times that the ink particles 9 on the nozzle forming surface 15 can be moved to the position in contact with the nozzles 14 as described above. Also, this number
It differs depending on the movable range and movable speed of the carriage, the size of the nozzle forming surface 15, the water repellency, and the like, and can be obtained by experiments. On some models, 10
Experiments have shown that it should be set to times.

The cleaning process shown in FIG. 3 is an example, and the ink suction process, the wiping / rubbing process, and the flushing process are selectively executed depending on various factors (for example, the elapsed time from the previous cleaning). The feature of the present invention is that the print head reciprocating process is performed after the ink suction process is performed.

As described above, according to the present embodiment,
Utilizing the property that the inside of the nozzle 14 of the print head 11 is in a negative pressure state, the ink particles 9 adhering to the nozzle surface 15 are removed by simply reciprocating the print head 11.
4 can be aspirated. As a result, the nozzle surface 15
It is possible to prevent not only printing defects due to missing dots caused by the ink particles 9 attached to the ink, but also to prevent deterioration of printing quality due to distortion of the ejection path of ink droplets to be printed.

In particular, in the case of the present embodiment, it is possible to prevent a printing defect and a deterioration of the printing essence due to the ink particles 9 on the nozzle surface 15 only by changing the control system without changing the mechanism system at all. Therefore, quick and simple response is possible.

Further, in such a measure, the ink particles 9
The moving range of the print head 11 for eliminating the print head is set to be the same as the normal print range.
Part of the program for executing normal printing can be cited in the program for executing Step 2, and as a result, the control system itself can have a simple configuration.

[0037]

As described above, according to the present invention, by reciprocating the carriage, the ink adhering to the nozzle forming surface is sucked into the ink nozzle of the print head which is in a steady state and under a negative pressure. Therefore, it is possible to prevent printing defects and deterioration in printing quality caused by ink particles on the nozzle surface.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a printer according to an embodiment.

FIG. 2 is a block diagram of a control system of the printer shown in FIG.

FIG. 3 is a flowchart illustrating a flow of a cleaning process according to the embodiment.

FIG. 4 is a diagram showing a state of a nozzle forming surface of a print head in the cleaning process shown in FIG.

FIG. 5 is a diagram illustrating a state of a nozzle forming surface of a print head in the cleaning process illustrated in FIG. 3;

FIG. 6 is a diagram illustrating a state of a nozzle forming surface of a print head in the cleaning process illustrated in FIG. 3;

FIG. 7 is a diagram illustrating a state of a nozzle forming surface of the print head in the cleaning process illustrated in FIG. 3;

8 is a diagram showing a state of a nozzle forming surface of a print head in the cleaning process shown in FIG.

9 is a diagram showing a state of a nozzle forming surface of a print head in the cleaning process shown in FIG.

[Explanation of symbols]

 Reference Signs List 11 print head 14 nozzle 15 nozzle surface 21 ink pump 24 first ink path 33 head cap 40 control unit 41 flushing means 42 print head reciprocating means

Claims (8)

[Claims] 1. A method of cleaning a print head of an ink jet printer for printing on recording paper by moving a carriage having a print head for discharging ink droplets, the method comprising: (a) sucking ink from ink nozzles of the print head; And (b) after step (a), reciprocating the carriage. 2. The print head cleaning method according to claim 1, wherein in the step (b), the carriage is reciprocated a predetermined number of times. 3. The print head cleaning method according to claim 1, wherein the step (b) reciprocates the carriage within a predetermined range. 4. An information recording medium having recorded thereon a program having the steps of the print head cleaning method for an ink jet printer according to claim 1. Description: 5. The information recording medium includes a compact disk, a floppy (registered trademark) disk, a hard disk, a magneto-optical disk, and a digital versatile disk.
The information recording medium according to claim 5, wherein the information recording medium is a disk, a magnetic tape, or a memory card. 6. An ink jet printer for performing printing on recording paper by moving a carriage equipped with a print head for discharging ink droplets, comprising: an ink suction pump for sucking ink from ink nozzles of the print head; A control unit for controlling the ink suction pump driving means for driving the ink suction pump to suck ink from the ink nozzles, and after the ink suction by the ink suction pump, An ink-jet printer comprising: a carriage driving means for reciprocating a carriage. 7. An ink jet printer according to claim 6, wherein said carriage driving means moves said carriage back and forth a predetermined number of times. 8. An ink jet printer according to claim 6, wherein said carriage driving means reciprocates the carriage within a predetermined range.