JP2871023B2 - Cleaning device for inkjet head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] Drop. on. Regarding the structure of the cleaning device of the inkjet head in the demand type inkjet printer, the purpose is to clean the nozzle surface of the inkjet head with a simple structure. The nozzle surfaces of a plurality of color-separated inkjet heads that perform multi-color recording by ejecting ink droplets from the nozzles are disposed opposite to a position deviating from the platen, cover the nozzle surfaces after printing is completed, and A plurality of color-specific purge capping units for sucking ink, and a plurality of color-specific wiping mechanisms adjacent to the purge capping unit and arranged to slide along a nozzle surface of an inkjet head to wipe off ink and the like. In the cleaning device, the inkjet head consisting of The wing unit is provided so as to be able to advance and retreat in opposition to the nozzle surface, and the wipe mechanism is rotatably stretched around an endless belt having fins protruding from a predetermined length of a smooth outer surface, and a part thereof is exposed to face. When the belt is rotated, the fins slide on the nozzle surface, the smooth surface without fins is arranged at a position separated from the nozzle surface, and the ink jet is printed on the front surface of the belt where only the smooth surface without fins is exposed. Move the head in opposition, rotate the belt, wipe the ink on the nozzle surface with the fins, stop the rotation again so that the smooth surface is exposed, and then move it to the front of the purge capping unit in the retracted position. After moving the inkjet head oppositely,
The purge capping unit is advanced to bring the front edge into contact with the nozzle surface to suck the ink, and to shut off the rotary drive system of the wipe mechanism.At the start of printing, the ink suction is stopped, and then the purge capping unit is turned off. At the same time, the rotary drive system of the wipe mechanism is restored, and the inkjet head is moved according to the print data to perform printing.

[Industrial applications]

The present invention relates to a drop. on. The present invention relates to a structure of an inkjet head cleaning device in a demand type inkjet printer.

Ink jet printers that perform printing by ejecting ink from a nozzle onto a recording medium are non-impact systems, and therefore generate less noise, have a higher recording speed, have better color development, and are easier to run. From the advantages of
Office automation (OA: Office Automation) is attracting attention as an alternative to wire dot printers, especially in the field.

However, this printer has an adverse effect on printing due to thickening of ink and residual ink, and thus measures are required.

[Conventional technology]

As shown in the plan view of FIG. on. In the demand type printer, an ink jet head 1 having a plurality of nozzles arranged in the direction of gravity is opposed to a platen 3 and reciprocates as shown by arrows BC, and selectively pressurizes the nozzles to eject ink droplets. The recording is performed on the recording medium 4 on the platen 3.

The platen 3 is rotatably held by the side frames 2a and 2b on both sides, and the recording medium 4 wound around the platen 3 is discharged in the direction of arrow A by the rotation of the platen 3.

On the other hand, a carrier 5 is slidably engaged with guide shafts 6 and 7 provided in parallel with the platen 3 on the front surface (the lower side in the figure) of the platen 3. The timing belt 8 is provided to be stretched over pulleys 9 and 10, and the carrier 5 fixed to one side 8a of the timing belt 8 by the forward / reverse rotation of the pulley 9 connected to the motor 11 as shown by arrows BC. To reciprocate.

An ink jet head 1 is mounted on the carrier 5, and ink is supplied to the ink jet head 1 from an ink tank 13 via a tube 12 that is flexible.

As shown in FIG.
A plurality of nozzles 20 from which ink droplets are ejected, and each nozzle 20
Ink passages 1c to 1k for supplying ink to the ink passages, and a common ink chamber 1b connected to each ink passage 1c to 1k for supplying ink.

Therefore, when recording on the recording medium 4, the nozzle of the ink jet head 1 is selected while reciprocating the ink jet head 1 together with the carrier 5, and a sudden pressure change is caused in the ink chamber in the head by the vibration of the electrostrictive vibrator or the like. Is applied and the ink is ejected in the form of drops.

In such an ink-jet head 1, the ink is dried and thickened, bubbles generated or entered in the ink liquid, mixed impurities and the like gather near the nozzle to cause clogging, and the pressure change described above is absorbed. There is a problem that ink ejection is not performed normally and causes printing failure.

As a countermeasure, when all printing is completed, in order to prevent the ink from drying and protect the nozzle surface from dust, so-called capping is performed to shut off the nozzle from outside air.
At the start of printing, a so-called purge is performed in which the thickened ink in the nozzles is forcibly sucked.

The purge capping unit 14 for performing such capping and purging is, for example, a platen 3 as shown in FIG.
Arrow D with respect to the ink jet head 1
It is provided so as to be able to protrude and retreat like -E.

As shown in the side view of FIG. 4, the purge capping unit 14 comprises a frame-shaped member 15 made of an elastic material such as ethylene propylene rubber so as to cover the entire nozzle surface 1a of the ink jet head 1, and a frame-shaped member 15 And a cap-shaped purge chamber 16 provided around the outer edge, and a vacuum pump 17 for discharging air in the purge chamber 16 through a tube 18a.
And a waste liquid tank 34 for storing the discharged ink, and a valve 19 communicating with the inside of the purge chamber 16 via the tube 18b.

Therefore, if the next printing is not to be performed immediately after the printing is completed, the inkjet head 1 is moved to the position of the purge capping unit 14 retracted in the direction of arrow E as shown in FIG. Close and purge chamber
Purge capping unit with 16 shut off from outside air
The frame 14 is protruded so that the frame-shaped member 15 is closely contacted so as to cover the entire nozzle surface 1a of the ink jet head 1 to shut off the outside air.

Then, when printing is started next, the vacuum pump 17 is driven to make the air in the purge chamber 16 a negative pressure, and the ink, bubbles and the like in the head are suctioned and removed through the nozzle 20.

After the removal is completed, the vacuum pump 17 is stopped, the valve 19 is opened to return the purge chamber 16 to the atmospheric pressure, and then the purge capping unit 14 is moved backward in the direction of arrow E.

Purging is performed as described above, but the nozzle surface 1a
Since purging alone is not sufficient to remove paper dust and thickened ink adhering to the nozzle, the wiper mechanism 21 is used to remove the nozzle surface.
Wiping and removing 1a.

The wipe mechanism 21 is provided between the purge capping unit 14 and the platen 3 as shown in FIG.
Like the purge capping unit 14, the purge capping unit 14 is provided so as to be able to advance and retreat in the direction of arrow E-D.

The endless belt 22 has a large number of fins 22a on the outside as shown in the side view of FIG. 5. The ink jet head 1 is moved so that the nozzle surface 1a is opposed to the belt 22 and then moved forward. To bring the fins 22a into contact with the nozzle surface 1a,
The belt 22 is rotated and wiped off by the fins 22a.

When only one inkjet head 1 is provided for monochromatic recording, one purge capping unit 14 and one wiping mechanism 21 may be provided, but a plurality of inkjet heads 1 are provided adjacent to each other for multicolor recording. In such a case, it is necessary to alternately arrange a plurality of purge capping units 14 and wipe mechanisms 21 at a predetermined pitch, as shown in the front view of FIG.

[Problems to be solved by the invention]

As described above, the cleaning device for the inkjet head is constituted by the wipe mechanism and the purge capping unit. However, since each of them is individually moved, the structure becomes complicated, resulting in an increase in cost.

In addition, if a plurality of ink jet heads are arranged in parallel for multi-color recording, ink adhering to the wipe mechanism may be applied to an adjacent ink jet head in order to simplify the structure by using the same mechanism. There is a problem that the color is adhered and mixed, and the recording quality is significantly deteriorated.

An object of the present invention is to perform cleaning of a nozzle surface of an inkjet head with a simple structure.

[Means for solving the problem]

In order to achieve the above object, in the present invention, as shown in the perspective view of FIG. 1 (a), the purge capping unit 14 is provided so as to be able to advance and retreat in opposition to the nozzle surface 1a, and the wipe mechanism 23 is provided. An endless belt 24 having fins 24a protruding from a predetermined length of an outer smooth surface 24b is rotatably stretched and partially exposed, and the fins are formed when the belt 24 is rotated.
24a slides on the nozzle surface 1a, the finless smooth surface 24b is disposed at a position separated from the nozzle surface 1a, and the inkjet head 1 is disposed on the front surface of the belt 24 exposing only the fin 24a smooth surface 24b. The belt 24 is rotated, and the ink on the nozzle surface 1a is wiped off by the fins 24a.
4b, the rotation is stopped so that only the opposite side is exposed, and then the inkjet head 1 is moved to the front of the purge capping unit 14 at the retracted position, and then the purge capping unit 14 is advanced to bring the front edge to the nozzle surface. 1a, the ink is suctioned, and the rotation drive system of the wipe mechanism 23 is shut off.With the start of printing, the ink suction is stopped, the purge capping unit 14 is retracted and stopped, and the wipe mechanism 23 is stopped. Is restored, and the inkjet head 1 is moved according to the print data to perform printing.

[Action]

After the smooth surface 24b of the belt 24 is made to face the nozzle surface 1a, the inkjet head 1 is moved to the front surface.

At this time, the belt 24 does not contact the nozzle surface 1a because the smooth surface 24b is exposed.

Thereafter, the belt 24 is rotated, and the fin 24a rotates the nozzle surface 1a.
And the rotation is stopped again so that only the smooth surface 24b is exposed to the opposite side.

Thereafter, the inkjet head 1 is moved to the front surface of the purge capping unit 14 at the retracted position, and the purge capping unit 14 is moved forward to come into contact with the nozzle surface 1a to suck ink.

At this time, the rotation drive system of the belt 24 is shut off and does not rotate.

As described above, only the purge capping unit 14 moves forward and backward with respect to the nozzle surface 1a, and the wipe mechanism
23 has only the rotation of the belt 24 and has a simple structure.

Also, when the inkjet head 1 moves, only the smooth surface 24b of the wiping mechanism 23 is exposed and separated from the nozzle surface 1a, so that the fins 24a slide on the nozzle surface 1a of a different color to cause contamination. No color mixing occurs.

Further, since a purge capping unit and a wiping mechanism are provided exclusively for each ink jet head for each recording color, the wiping operation or the purge capping operation can be performed simultaneously for all the heads, thereby reducing the operation time. I can do it.

〔Example〕

 1 and 2 show one embodiment of the present invention.

 The same reference numerals are given to the same parts throughout the drawings.

As shown in the perspective view of FIG. 1 (a), the cleaning device for an ink jet head according to the present invention includes a purge capping unit 14 and a wiping mechanism 23, and the purge capping unit 14 has a nozzle surface 1a as in the prior art. Are provided so as to be able to move forward and backward.

The wipe mechanism 23 is provided with a plurality of fins 24 on a predetermined length of the outer surface of the endless belt 24 as shown in the side view of FIG.
When the belt 24 is stretched by pulleys 25a and 25b, one half is a surface on which the fins 24a are protruded, and the other half is a smooth surface 24b without the fins 24a. Have been.

The belt 24 is made of an elastic material such as ethylene propylene rubber, and when rotated, the fins 24a slide on the nozzle surface 1a, and the smooth surface 24b is provided at a position separated from the nozzle surface 1a with a gap. Have been.

That is, the purge capping unit 14 is as shown in FIG.
A predetermined number is fixed to the front surface of the substrate 26 at a predetermined pitch as shown in FIG.

The substrate 26 is moved by an arrow E-D by an advance / retreat mechanism (not shown).
It is possible to move like.

On the other hand, the belt 24 of the wipe mechanism 23 is also attached to the substrate 26, and is rotatably stretched by pulleys 25a and 25b.

The rotation shaft 27 of the pulley 25a has a gear 28 outside the substrate 26, and the gear 28 meshes with the drive gear 29.

The drive gear 29 is fixed to a support plate 30 that supports the substrate 26 so as to be able to advance and retreat, and meshes with a gear 32 of a motor 31 via an idle gear 33.

The drive gear 29 meshes with a gear 35 for driving the vacuum pump 17.

Accordingly, when the motor 31 is driven in this state, FIG.
As shown in FIG. 7, the belt 24 rotates clockwise, and the fins 24a slide on the nozzle surface 1a to perform cleaning.

When the belt 24 further rotates, the belt 24 exposes the smooth surface 24b and separates from the nozzle surface 1a.

The drive of the purge capping unit 14 is shown in FIG.
After the substrate 26 is projected as shown in the side view of FIG.
And the vacuum pump 17 is driven.

At this time, the gear 28 is separated from the drive gear 29 by the movement of the substrate 26, and the belt 24 does not rotate because the rotary drive system is shut off, and the fins 24a slide on the nozzle surface 1a of the adjacent inkjet head 1. It does not move and pollute.

Therefore, the cleaning of the nozzle surface 1a is performed by rotating the belt 24 to rotate the smooth surface 24b so as to face the nozzle surface 1a, and then moving the inkjet head 1 to the front surface of the wiping mechanism 23, and retreating the purge capping unit 14. Gear
The belt 24 is rotated by meshing the drive gear 29 with the drive gear 29, and the ink on the nozzle surface 1a is wiped off by the fins 24a.

Then, the purge capping unit in the retracted position
The inkjet head 1 is moved to the front side of 14.

Then, the purge capping unit 14 is advanced to come into contact with the nozzle surface 1a, and the vacuum pump 17 is driven to suck ink.

The above purge capping unit 14 and wipe mechanism 23
Is simultaneously performed for all the plurality of ink jet heads 1 for each color for multi-color recording.

FIG. 2 is a perspective view showing another embodiment of the present invention, wherein the wiping mechanism 23 is not fixed to the substrate 26,
It is in the home position without being affected by the 26 retreats.

The purge capping unit 14 is fixed to the substrate 26, and reciprocates with respect to the nozzle surface 1a by the reciprocating motion of the substrate 26 as in the prior art.

The rotation of the wipe mechanism 23 is performed by transmitting the rotation of the timing pulley 36 provided coaxially with the drive gear 29 to the timing pulley 38 of the wipe mechanism 23 via the timing belt 37.

The timing pulley 38 is attached to the rotating shaft 27 via a one-way clutch 39 that rotates only clockwise, so that the belt 24 rotates only clockwise.

With this configuration, the cleaning operation is performed by moving only the purge capping unit 14 forward and backward depending on the substrate 26, and the motor 31 is rotated reversely (counterclockwise) during suction.
Then, the operation is performed by driving the vacuum pump 17.

At this time, since the timing pulley 38 of the wipe mechanism 23 is in the counterclockwise direction, the rotation drive system is shut off and the belt 24 does not rotate.

In the above description, the purge capping is performed after the wipe. However, the purge capping may be performed in the reverse order depending on the operation conditions of the apparatus.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the structure of a cleaning apparatus becomes simple, low cost is implement | achieved, the color mixing by a wiping operation | movement can be prevented, and excellent recording can be performed. To play.

[Brief description of the drawings]

FIG. 1A is a perspective view of a cleaning device for an ink jet head of the present invention, FIGS. 1B and 1C are side views of the operation state of FIG. 1A, and FIG. 2 is another embodiment. FIG. 3 is a plan view of an ink jet printer to which the present invention is applied, FIG. 4 is a side view of an ink jet head and a purge capping unit, FIG. 5 is a side view of a conventional wipe mechanism, FIG. FIG. 2 is a front view of a conventional cleaning device. In the figure, 1 is an ink jet head, 1a is a nozzle surface, 3 is a platen, 12, 18a, 18b, a tube, 13 is an ink tank, 14
Is a purge capping unit, 16 is a purge chamber, 17 is a vacuum pump, 19 is a valve, 20 is a nozzle, 21 and 23 are wipe mechanisms, 22, 24 are belts, 22a and 24a are fins, 24b is a smooth surface, 25a and 25b Is a pulley, 26 is a substrate, 27 is a rotating shaft, 2
8, 32 and 35 are gears, 29 is a drive gear, 30 is a support plate, 31 is a motor, 33 is an idle gear, 34 is a waste liquid tank, 36 and 38 are timing pulleys, 37 is a timing belt, and 39 is a one-way clutch. .

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-251146 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2 / 165,2 / 18,2 / 185

Claims (1)

(57) [Claims] A plurality of color-separated ink jets which reciprocate in opposition to a platen (3) and eject ink droplets from nozzles onto a recording medium on the platen (3) to perform multicolor recording. A plurality of color-specific inks are disposed opposite to the nozzle surface (1a) of the head (1) and away from the platen (3) to cover the nozzle surface (1a) and to suck ink in the head after printing is completed. A purge capping unit (14), and a plurality of juxtaposed adjacent to the purge capping unit (14), which slide on the nozzle surface (1a) of the ink jet head (1) to wipe off ink and the like. In the cleaning device for an ink jet head comprising a color-specific wiping mechanism (23), the purge capping unit (14) is provided so as to be able to advance and retreat in opposition to the nozzle surface (1a); The frame (23) is an endless belt (24) with fins (24a) protruding at a predetermined length on the outer smooth surface (24b).
The fin (24a) slides on the nozzle surface (1a) when the belt (24) is rotated, and the finless smooth surface (24b) ) Is disposed at a position separated from the nozzle surface (1a), and the inkjet head (1) faces the front surface of the belt (24) exposing only the smooth surface (24b) without the fin (24a). The belt (24) is rotated to wipe the ink on the nozzle surface (1a) with the fins (24a), and the smooth surface (24b) is again moved.
Then, the inkjet head (1) is opposed to the front surface of the purge capping unit (14) at the retracted position, and then the purge capping unit (14) is moved. The ink is sucked by moving the front edge to the nozzle surface (1a) so as to suck the ink, and the rotation drive system of the wipe mechanism (23) is cut off. The purge capping unit (14) is retracted and stopped, and the rotary drive system of the wipe mechanism (23) is restored, so that the inkjet head (1) is moved according to print data to perform printing. Cleaning device for inkjet head.