JPH11277770A - Cleaner for ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaner for cleaning the inside of nozzles having different diameter in an ink jet head. SOLUTION: A suction head 17 being applied tightly to the surface of an ink jet head where nozzles are formed is provided with first and second negative pressure chambers 59, 61. A conduction path 75 having a reed valve 77 is formed in the wall 57 for partitioning the chambers 59, 61. When a negative pressure is formed in the first pressure chamber 59 with the suction head 17 touching the ink jet head tightly and suction is started through a nozzle facing the first pressure chamber 59, a gap is formed between the reed valve 77 and the conduction path 25 and a negative pressure 15 formed in the second pressure chamber 61 to start suction through a nozzle facing the second pressure chamber 61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head cleaning apparatus for cleaning nozzles of an ink jet head.

[0002]

2. Description of the Related Art In a printer having an ink jet head, when the printer has not been used for a long time or when ink is replaced, it is necessary to remove ink scum and residual ink inside the nozzle and clean the inside of the nozzle of the ink jet head. There is. Conventionally, a cleaning device has been used to clean the inside of a nozzle of an inkjet head. The cleaning device includes a housing having an opening and a negative pressure generating means connected to the housing.After the opening is brought into close contact with the surface of the ink jet head on which the nozzles are formed, the negative pressure generating means is provided. By driving and forming a negative pressure inside the housing, ink residue and the like are sucked out from the inside of the nozzle and the inside of the nozzle is cleaned.

[0003]

However, in the above-described cleaning apparatus, when the ink jet head has nozzles having different diameters, it is impossible to uniformly generate a negative pressure on the nozzles having different diameters. For this reason, the ink scum and the like are sucked from the large-diameter nozzle, but the ink scum and the like are not sucked from the small-diameter nozzle, and the small-diameter nozzle is not sufficiently cleaned. For this reason, after cleaning, there is a problem that a nozzle having a small diameter may hinder printing.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and an ink jet head cleaning apparatus according to the present invention has an opening which is in close contact with a surface of an ink jet head where nozzles are formed. A suction means is connected to one of the plurality of hollow housings, and a valve is provided in a communication passage connecting the hollow housing to which the suction means is connected and another hollow housing. In the state where the opening of is closely attached to the surface of the inkjet head where the nozzles are formed,
When the suction means is operated and the hollow housing to which the suction means is connected starts suctioning the nozzle of the inkjet head facing the opening of the hollow housing, the valve is opened and the opening of the other hollow housing is opened. The suction of the nozzle of the ink jet head facing the nozzle is started.

Further, the valve is characterized in that it is constituted by a reed valve which opens the communication passage when a predetermined negative pressure is formed inside the hollow housing to which the suction means is connected.

Further, the communication passage is partially formed of an elastic member, and the valve is formed of a cam mechanism abutting on a portion formed by the elastic member. The communication passage may be closed and opened by deformation.

[0007]

In the ink jet head cleaning apparatus according to the present invention, when cleaning an ink jet head having nozzles of different diameters, the opening of the housing in which the suction means is connected to the nozzle having a small diameter is used. The opening of the other housing is opposed to and adhered to another nozzle. Next, the suction means is driven to create a negative pressure inside the housing to which the suction means is connected, and suction the nozzle having a small diameter. When the suction of the nozzle is started, the valve is opened, a negative pressure is formed inside another housing, and the suction of the other nozzle is started.

As described above, in the ink jet head cleaning apparatus according to the present invention, even if the ink jet head is provided with nozzles having different diameters, a predetermined time is required after the suction of the small diameter nozzles is started. At this time, the suction of the other nozzles is started, so that all the nozzles including the small-diameter nozzles are sufficiently cleaned. Therefore, in the above-described ink jet head, since there is no problem such as clogging of the nozzle with the ink residue, a good image can be formed.

In the cleaning device for an ink jet head in which the above-mentioned valve is constituted by a reed valve, after suction of a small-diameter nozzle is started, if a negative pressure is formed inside a housing to which suction means is connected, Since the reed valve opens the communication passage due to the negative pressure, a time difference until the negative pressure is formed between the two can be easily created.

Further, in an ink jet head cleaning apparatus in which a part of the communication path is formed by an elastic member and the valve is constituted by a cam mechanism in contact with the part formed by the elastic member, the cam mechanism is driven. Since the above-mentioned portion formed of an elastic member is elastically deformed to close and open the above-mentioned communication passage, by driving the cam mechanism arbitrarily, after the suction of the small-diameter nozzle is started, the communication passage is opened. Thus, a negative pressure can be formed inside the other housing, and suction of another nozzle can be started.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a part of an inkjet printer 1 (hereinafter simply referred to as a printer). The printer 1 includes a transport mechanism 5 for transporting the recording paper 3 in the direction of arrow y, a cartridge 7 containing ink for recording an image on the upper surface of the recording paper 3, and A scanning mechanism 9 for reciprocating in the x direction orthogonal to the transport direction y direction.
The cartridge 7 has a box-shaped container in the present embodiment, and has an ink jet head 11 on one side facing the recording paper 3.

A cleaning device 15 is provided at a home position 13 which is a non-printing area of the ink jet head 11. The cleaning device 15 includes a suction head 17, a cam mechanism 19 for moving the suction head 17 forward and backward (z direction) with respect to the inkjet head 11 moved to the home position 13, and a negative pressure for generating a negative pressure in the suction head 17. And a pressure generating device (suction means) 21.

FIG. 2 is a partially enlarged front view of the head 11, and FIG. 3 is a cross-sectional view of the head 11 taken along line III-III in FIG. FIG. 4 shows a cross section of the head 6 along the line IV-IV in FIG. As shown in these figures, the head 11 is located adjacent to the first
Head part 22 (first head area) and second head part 24
(Second head area). Head 11
Is constructed by integrally combining a nozzle plate 26, a diaphragm 28, diaphragms 30, 31, an outer wall plate 32, and a base plate 33. First head section 22
Is used, for example, when a small-diameter ink droplet of 30 to 60 μm is ejected.
Used when ejecting large diameter ink droplets of 120 μm.

The nozzle plate 26 has a first surface 26a facing the recording paper 3 and a second surface 26a located on the opposite side.
b, and applying a processing technique such as electroforming or photolithography to the second surface
And the second head portion 24, a plurality of long grooves for storing ink, ie, pressurizing chambers 36 and 37, replenishing chambers 40 and 41 for storing replenishing ink, and pressurizing chambers 36 and 37, respectively. The pressurizing chambers 36 and 37 are provided in the supply chamber 40,
The passages 42 and 43 communicating with the pressure chambers 41 and the pressurizing chambers 36 and 37
And a plurality of nozzles 44 and 45 for ejecting ink in the pressure chambers 36 and 37 are formed.

On the second surface 26b of the nozzle plate 26,
A diaphragm (partition wall) 28 made of a nickel plate material is attached, and thereby the openings of the pressurizing chambers 36 and 37, the supply chambers 40 and 41, and the passages 42 and 43 on the second surface 26b are closed. ing. The diaphragm 28 deforms according to the deformation of the diaphragms 30 and 31 without hindering the deformation of the diaphragms 30 and 31 described later.

The ink is stored in a storage unit (not shown).
The pressure is supplied to each of the pressurizing chambers 36 and 37 through the third pressurizing chamber 3.

In each of the head sections 22 and 24, a plurality of pressurizing chambers 36 and 37 are formed in parallel at a predetermined interval in a direction substantially orthogonal to the head center line 23. The nozzles 44 and 45 are provided near the center line of the pressurizing chambers 36 and 37 at a predetermined distance from the center line, and the inside of each pressurizing chamber 36 and 37 is adjacent to the first surface 26a. Communicates with atmosphere. The nozzles 44 and 45 are tapered so as to gradually become thinner toward the first surface 26a.
The inner surface may have any shape. Further, since the nozzle 44 ejects a small diameter ink droplet, its diameter is 22 μm.
m, and the nozzle 45 has a diameter of 32 μm in order to eject a large-diameter ink droplet.

The vibrating plates 30 and 31 press the ink in the pressurizing chamber 36 of the first head section 22 and the ink in the pressurizing chamber 37 of the second head section 24, respectively, and pressurize the pressurizing chamber 36 with the diaphragm 28 interposed therebetween. The diaphragm 30 is disposed at the facing portion of
The diaphragm 31 is disposed at a portion facing the pressure chamber 37 with the diaphragm 28 interposed therebetween. The diaphragms 30 and 31 have a plurality of PZs.
A substrate (piezoelectric member) made of T is formed by laminating the electrodes. A thin plate-shaped electrode is sandwiched between the substrates (not shown), and polarization processing is performed using this electrode.

The vibration plates 30 and 31 are not limited to those composed of a plurality of piezoelectric ceramic substrates, but may be those obtained by subjecting a piezoelectric ceramic substrate having a single plate shape to polarization processing.

On the outer periphery of the diaphragms 30 and 31, a diaphragm 3
An outer wall plate 32 having the same thickness as that of the ink supply chambers 0 and 31 is provided.
It supports the diaphragm 28 which is in contact with 0 and 41.

The base plate 33 supporting the diaphragms 30, 31 and the outer wall plate 32 has a plurality of conductive leads (not shown).
0, 31 are connected to electrodes (not shown) on the side surfaces. Thus, when a predetermined voltage is applied to the electrode, the diaphragm 3
0 and 31 are deformed in the thickness direction, and the deformation is transmitted to the ink in the corresponding pressure chambers 36 and 37 via the diaphragm 28.

In the head 11 having the above-described structure, ink is supplied to the ink supply chambers 40 and 41 from an ink tank (not shown) to each of the head sections 22 and 24. The ink in the ink supply chambers 40 and 41 is supplied to an ink inlet 42,
It is distributed to each of the pressurizing chambers 36 and 37 via 43. Also,
As shown in FIG. 1, the head 11 reciprocates in the x direction according to the movement of the carriage 7. When a predetermined drive voltage is applied to the diaphragms 30, 31, the diaphragms 30, 31 deform toward the corresponding pressurizing chambers 36, 37, and the deformation is transmitted to the diaphragm 28. As a result, the ink in the pressurizing chambers 36 and 37 is pressurized, the ink droplets fly from the nozzles 44 and 45, and adhere to the recording paper 3 fed in the y direction in the facing portion of the head 11 to form an image. You.

Next, the cleaning device 15 which is a feature of the present invention will be described. If the printer 1 is not used for a long period of time, the ink residue may be clogged inside the nozzles 44 and 45 of the head 11 or dust may adhere. Further, when replacing ink, old ink may remain inside the nozzles 44 and 45. Since these cause printing defects, it is necessary to clean the inside of the nozzles 44 and 45. The printer 1 includes a cleaning device 15 for cleaning the inside of the nozzles 44 and 45.

FIG. 5 shows the front of the suction head 17 of the cleaning device 15 (the surface facing the head 11). FIG. 6 shows a cross section of the suction head 17 along the line VI-VI in FIG. 5, and FIG. 7 shows a cross section of the suction head 17 along the line VII-VII in FIG. The suction head 17
A base body having a U-shaped cross section is used for sucking ink residue and the like inside the nozzles 44 and 45 in close contact with the first surface 26a of the nozzle plate 26 of the head 11, as shown in these figures. The housing portion 53 is provided in the concave portion 51 of the housing 50.
Is attached. The base body 50 has an engaging portion 54 that engages with a guide rail 81 described later.

The housing portion 53 is formed to have substantially the same size as the nozzle plate 26 of the head 11, and is made of an elastically deformable material such as, for example, an elastically deformable material so as to bring the housing portion 53 into close contact with the first surface 26a. It is formed of silicone, chloroprene rubber, butyl rubber, urethane rubber, or fluorosilicone rubber. The housing 53
Is provided with a partition wall 57 in the front opening 55, and the opening 55 is formed by a first negative pressure chamber 59 having substantially the same size as the first head section 22 of the head 11, and a second head section of the head 11. And a second negative pressure chamber 61 having a size substantially equal to 24. Step portions 63 and 65 are formed in the first negative pressure chamber 59 and the second negative pressure chamber 61, respectively.
, Ink suction sheets 67 and 69 are placed on the sheet. The ink suction sheets 67 and 69 have air permeability and are formed of a material that absorbs ink, for example, a urethane foam material or a sponge material. Further, the ink suction sheet 67 is
The first negative pressure chamber 59 is partitioned inside the housing portion 53 to form a first suction chamber 71. Similarly, the ink suction sheet 69 partitions the second negative pressure chamber 61 inside the housing portion 53 to form a second suction chamber 73.

A groove 58 is formed in the upper end 57a of the partition wall 57, and the upper end 57a is easily deformed so that the upper end 57a and the first surface 26a of the nozzle plate 26 of the head 11 are good. It comes to adhere to. A communication passage 75 that connects the first suction chamber 71 and the second suction chamber 73 is formed at the lower end 57 b of the partition wall 57. A reed valve 77 for closing the communication passage 75 is provided inside the first suction chamber 71. The reed valve 77 is a thin plate made of stainless steel and having a thickness of 0.3 mm.
b is fixed inside the first suction chamber 71. When a predetermined negative pressure is formed inside the first suction chamber 71, the reed valve 77 moves its upper end 77 a toward the first suction chamber 71 and a gap of about 0.1 mm between the reed valve 77 and the communication passage 75. Is formed so that the first suction chamber 71 and the second suction chamber 73 communicate with each other.

The reed valve 77 is not limited to stainless steel, but is made of a durable material that satisfies conditions such as no rust, for example, ABS resin, polypropylene,
Polycarbonate or the like may be used. Also, the reed valve 7
7 is not limited to 0.3 mm,
When the inside of the suction chamber 71 has a pressure of 0.85 atm, the thickness may be any thickness that can form a gap of about 0.1 mm between the suction chamber 71 and the communication path 75.

A suction pipe 79 connected to the negative pressure generator 21 is attached to the bottom of the first suction chamber 71.

Next, the cam mechanism 1 of the cleaning device 15
9 will be described. The cam mechanism 19, as described above,
The suction head 17 is moved forward and backward to the head 11 moved to the home position 13, and the housing portion 5 of the suction head 17 is moved.
The guide rail 81 is used to bring the engaging portion 54 formed on the base main body 50 into engagement with the suction head 17, as shown in FIG. , A gear 85 provided on the rotation shaft of the flat cam 83,
The gear 87 includes a gear 87 that meshes with the gear 87 and a pulse motor 89 to which the gear 87 is attached.

In the cam mechanism 19 having the above-described structure, when the flat cam 83 rotates by a predetermined angle in accordance with the rotation angle of the pulse motor 89, the suction head 17 is guided by the guide rail 81 and moves a predetermined distance from the head 11. It moves in the direction of the arrow z. Note that, instead of the cam mechanism 19, the suction head 17 may be moved toward and away from the head 11 by a well-known link mechanism, a lift mechanism using a cylinder, or the like.

A tube 91 is attached to the negative pressure generator 21, and this tube 91 is connected to a suction pipe 79 of the first suction chamber 71.

FIG. 8 is a block diagram showing a control system for controlling the operation of the printer 1 and the operation of the cleaning device 15. Central information processing unit (CPU) 1
00, a RAM 101 for recording data and the like received from the host unit and the like, a ROM 103 for recording an operation control program, and a data receiving unit 105 for data communication from the host unit and the like. A head ejection drive unit 107 for controlling the motor, a head movement drive unit 109 for driving the motor of the carriage 7 to move the head in synchronization with the recording timing of the head 11, and a paper feed drive unit 111 for controlling the conveyance of the recording paper 3. , The pulse motor 89 of the cam mechanism 19
Mechanism driving unit 113 for controlling the pressure and negative pressure generator 21
And a variety of sensor units 117 disposed at respective positions to detect whether the head 11 is moving to the home position 13, whether or not the recording paper 3 is present, whether or not ink is present, and the like. Is connected.

In this control system, the cleaning device 15 is driven to clean the nozzles 44 and 45 of the head 11 when the printing amount reaches a predetermined amount. , 45 to be cleaned. Also, the diaphragm 3 at a specific voltage
Nozzles 44, from the electrical resistance value when driving 0, 31
The nozzles 44 and 45 may be cleaned by detecting the clogging of the nozzle 45.

Next, the specific operation of the cleaning device 15 for cleaning the nozzles 44 and 45 of the head 11 will be described. As described above, the cleaning device 15 starts operating when the printing amount of the printer 1 reaches a predetermined amount. After detecting that the head 11 has moved to the home position 13, the cleaning device 15 operates the cam mechanism 19 to bring the suction head 17 into close contact with the head 11. At this time, the first negative pressure chamber 59 of the suction head 17 is in close contact with the first head section 22 (first head area) of the head 11, and the second negative pressure chamber 61 is in contact with the second head section 24 (second head area). Adhere to

After the suction head 17 comes into close contact with the head 11, the negative pressure generator 21 is driven to generate a negative pressure in the first suction chamber 71. Since the first suction chamber 71 and the first negative pressure chamber 59 are separated by the ink suction sheet 67 having air permeability, a negative pressure is also generated in the first negative pressure chamber 59. Due to this negative pressure, ink residue and the like are discharged from the inside of the nozzle 44 of the first head unit 22 toward the suction sheet 67 and captured by the suction sheet 67.

When the ink residue or the like is discharged from the inside of the nozzle 44 of the first head section 22 as described above, the upper end 77a of the reed valve 77 is moved to the first suction chamber 7 as shown in FIG.
By moving to the first side, a gap 78 is formed in the communication path 75. A negative pressure is formed inside the second suction chamber 73 through this gap, and a negative pressure is also generated in the second negative pressure chamber 61. Due to the negative pressure formed in the second negative pressure chamber 61, ink residue and the like are discharged from the inside of the nozzle 45 of the second head portion 24 toward the suction sheet 69 and captured by the suction sheet 69.

As described above, in the cleaning device 15,
There is a time difference between the start of the cleaning of the nozzle 44 having a small diameter of the first head portion 22 and the start of the cleaning of the nozzle 45 having a large diameter of the second head portion 24 (the reed valve 77 moves to the Time until the gap 78 is formed)
Since the negative pressure does not concentrate only on the large-diameter nozzle 45 of the second head portion 24, the small-diameter nozzle 44 of the first head portion can be sufficiently cleaned. Therefore, the head 11 does not cause printing defects after cleaning.

After driving the negative pressure generator 21 for a predetermined time,
The negative pressure generator 21 is stopped, the cam mechanism 19 is driven to lower the suction head 17, and the suction head 17 and the head 11
Is separated, and the head 11 is moved to the printing area to end the cleaning operation.

Although the suction head 17 has a structure in which the reed valve 77 is directly mounted inside the first suction chamber 71, as shown in FIG. May be attached to the end of the first suction chamber 71 side. Further, as shown in FIG. 11, a part 57c of the partition wall 57 may be formed by the base body 50, the communication path 75 may be formed in the base body 50, and the reed valve 77 may be attached to the partition wall 57. .

Further, as shown in FIGS. 12 and 13,
The communication passage 75 includes a tube 121 disposed outside the housing portion 53, a communication passage 122 communicating with the first suction chamber 71 communicating with the tube 121, and a communication passage 123 communicating with the second suction chamber 73. The reed valve 77 may be provided at the end of the communication passage 122 facing the inside of the first suction chamber 71.

The mechanism for opening and closing the communication passage 75 is not limited to the reed valve 77, but may be a flat cam 125 as shown in FIG. The above flat cam 1
The space 25 is disposed in a space 127 formed below the partition wall 57, and as shown in FIG.
The communication passage 75 can be closed by elastically deforming the partition wall 57 on the upper part of the 27.

The flat cam 125 is provided so as to be rotated by a pulse motor (not shown).
The rotation angle of No. 5 is detected by the position detection sensor 129. The suction head 17 includes a pressure sensor 131 in the first negative pressure chamber 59.
Detects that a predetermined negative pressure has been formed inside the first negative pressure chamber 59, starts driving the pulse motor. In the suction head 17, the user may arbitrarily control the pulse motor to close or open the communication path 75. Thus, the time difference between the start of suction of the nozzle 44 and the start of suction of the nozzle 45 can be set arbitrarily. For example, after the nozzle 44 is continuously cleaned, the cleaning of the nozzle 45 is started. be able to.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of a printer provided with an inkjet head cleaning device according to the present invention.

FIG. 2 is a partial front view of the ink jet head.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a front view of a suction head.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 5;

FIG. 8 is a block diagram illustrating a control system of the printer.

FIG. 9 is an explanatory diagram showing the operation of the reed valve.

FIG. 10 is a sectional view showing a modification of the suction head.

FIG. 11 is a sectional view showing a modification of the suction head.

FIG. 12 is a front view showing a modified example of the suction head.

13 is a sectional view taken along line XII-XII in FIG.

FIG. 14 is a sectional view showing a modified example of the suction head.

15 is an explanatory diagram showing a state in which a communication path of the suction head shown in FIG. 14 is closed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Printer, 11 ... Ink jet head, 15 ... Cleaning device of ink jet head, 17 ... Suction head, 19 ... Cam mechanism, 21 ... Negative pressure generator, 59 ... 1st negative pressure chamber, 61 ... 2nd negative pressure chamber, 57 ... partition wall, 75 ...
Communication passage, 77 ... reed valve.

Claims (3)

[Claims] A suction means is connected to one of a plurality of hollow housings having an opening which is in close contact with a surface of an ink jet head on which a nozzle is formed, and a hollow housing to which the suction means is connected and another hollow housing. A valve is provided in a communication passage communicating with the housing, and in a state where the respective openings of the plurality of hollow housings are in close contact with the surface of the inkjet head where the nozzles are formed, the suction unit is operated to connect the suction unit. When the hollow housing starts suctioning the nozzle of the inkjet head facing the opening of the hollow housing, the valve opens, and suction of the nozzle of the inkjet head facing the opening of the other hollow housing starts. A cleaning device for an inkjet head. 2. The valve according to claim 1, wherein the valve is a reed valve that opens the communication passage when a predetermined negative pressure is formed inside the hollow housing to which the suction unit is connected. 2. The cleaning device for an inkjet head according to 1. 3. A part of the communication passage is formed of an elastic member, and the valve is formed of a cam mechanism that abuts on a part formed by the elastic member. 2. The cleaning device for an ink jet head according to claim 1, wherein the communication path is deformed to close and open the communication path.