Head cleaning device

Abstract

To provide a wiper type head cleaning device which can be used so as to match with a print width in drop-on-demand (DOD) type inkjet printers having column lengths of ink nozzles which vary by models.SOLUTION: The invention relates to a head cleaning device 10 which wipes a nozzle arrangement surface 13a in a printer head 1 of a DOD type inkjet printer 100 with a plate-like wiper blade 2. In the printer head 1 of the DOD type inkjet printer 100, a number of nozzles 1a, ... are arranged in a column direction. In the invention, the plate-like wiper blade 2 is slid in the column direction of the nozzles 1a, 1a, ... when wiping the nozzle arrangement surface 13a. Thus, the same wiper blade 2 can be used independently of a column length of the nozzles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a head cleaning device for a drop-on type ink jet printer (hereinafter referred to as "DOD type IJP"), and more particularly to a head cleaning device that wipes ink adhering to the nozzles with a wiper. [Background technology]

[0002] In DOD type IJPs, which have many ink nozzles on the nozzle surface of the printer head, wipers are provided to wipe the nozzle surface to remove residual ink adhering around the nozzles and foreign matter such as paper fibers generated from the printed object (see Patent Documents 1 and 2).

[0003] For example, Patent Document 1 discloses a head cleaning device in which a strip-shaped wiper with many rectangular openings arranged in a row along its length is pulled out from a roll set on an upstream reel, and is run while in contact with the nozzle surface of the printer head to clean the nozzle surface, after which it is taken up onto a downstream reel.

[0004] Furthermore, Patent Document 2 discloses a head cleaning device for a DOD type IJP in which the nozzle surface is wiped with a wiper blade having a triangular cross section that matches the size (print width) of the head. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3840452 [Patent Document 2] Patent No. 3790754 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in DOD-type IJPs, the number of nozzles and the range (length) over which the nozzles are arranged vary depending on the model to accommodate different print widths, and the head cleaning device of Patent Document 1 is configured so that the width direction of the strip-shaped wiper is aligned with the vertical direction of the nozzles and the strip-shaped wiper runs perpendicular to the vertical direction of the nozzles, so it is necessary to manufacture strip-shaped wipers with a width that matches the head size (print width) for each printer model, and also in the head cleaning device of Patent Document 2, the wiper blade is configured to wipe the nozzle surface perpendicular to the vertical direction of the nozzles, so the width of the wiper blade needs to be changed for each model. The present invention has been made in view of the above-mentioned problems, and has as its object to provide a head cleaning device equipped with a wiper that can be used in common for different models of DOD type IJPs. [Means for solving the problem]

[0007] The invention made to solve the above problem is a head cleaning device that uses a wiper blade to wipe the nozzle arrangement surface, on which a large number of nozzles are arranged in a vertical row, of a DOD-type IJP printer head, and is characterized in that the wiper blade is plate-shaped and slides in the thickness direction of the plate toward the vertical row to wipe the nozzle arrangement surface. Here, "plate-shaped" means that at least a portion of the tip of the wiper blade is plate-shaped. Also, "with the plate thickness direction facing the vertical row direction" means that the angle θ (see FIG. 4(d)) between the plate thickness direction S1 and the nozzle vertical row direction S2 is between 0 degrees and 45 degrees.

[0008] In the head cleaning device of the present invention, the wiper blade is slid in the vertical direction of the nozzles with its thickness facing the nozzle row, so even if the number of nozzles arranged in the vertical direction or the length of the nozzle row varies depending on the printer model, it is sufficient to change the sliding distance of the nozzles, and there is no need to change the width of the wiper blade. Also, by making the wiper blade plate-shaped, it is possible to prevent paper dust and the like from becoming trapped between the nozzle arrangement surface and the wiper blade.

[0009] It is preferable that the tip of the wiper blade is provided on a straight line parallel to the nozzle arrangement surface when viewed in the plate thickness direction, so that the tip of the wiper blade can more effectively abut against the nozzle arrangement surface.

[0010] The wiper blade is preferably flexible and configured to wipe the nozzle arrangement surface with its tip inclined rearward in the wiping direction, so that the tip of the wiper blade can be brought into close contact with the nozzle arrangement surface by the elastic force generated by the bending of the wiper blade when it slides over the nozzle arrangement surface.

[0011] The head cleaning device of the present invention is preferably configured to wipe the nozzle arrangement surface with the wiper blade after performing a purging operation (hereinafter referred to as "purging") in which ink is forcibly ejected from the nozzles with the nozzle arrangement surface facing downward to expel air bubbles from the ink passages and chambers to the outside. In this way, ink can be used as a lubricant when wiping the nozzle arrangement surface with the wiper blade.

[0012] The head cleaning device of the present invention preferably includes an ink pan for receiving ink purged from the nozzles. The head cleaning device in Patent Document 1 had the problem that as the number of nozzles increased, the amount of ink discharged by purging also increased, so more disposable wipers were needed to wipe it off reliably.By providing an ink pan to receive the ink purged from the nozzles, there is no need to provide a disposable member to absorb the purged ink.

[0013] The head cleaning device of the present invention preferably includes a wiping member that wipes away ink adhering to the wiper blade, thereby suppressing adhesion of paper dust to the wiper blade and solidification of ink on the wiper blade, and suppressing damage to the nozzle arrangement surface when the wiper blade wipes the nozzle arrangement surface.

[0014] The wiping member is preferably a columnar or cylindrical wiping roll that is provided on an extension of the row direction outside the nozzle arrangement surface and has a rotation axis direction perpendicular to the row direction. By arranging the rotation axis of the wiping roll perpendicular to the row direction of the nozzles in this way, the width direction of the wiper blade and the width direction of the wiping roll can be aligned, eliminating the need to change the width of the wiping roll for each model. [Effects of the Invention]

[0015] As described above, with the head cleaning device of the present invention, the same wiper blade can be used in common for a plurality of types of DOD type IJPs that have different numbers of nozzles arranged in the vertical direction and different lengths of nozzle arrangement. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing an overview of an inkjet printer equipped with a head cleaning device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of the wiper blade shown in FIG. 1. [Figure 3] FIG. 2 is a perspective view of the wiping roll shown in FIG. 1 disassembled from the rotary shaft. [Figure 4] (a) to (c) are schematic diagrams showing the positional relationship between the nozzle arrangement surface of the printer head shown in Figure 1, the wiper blade, and the wiping roll, as seen from the front, side, and bottom, respectively, and (d) is an explanatory diagram of the angle between the thickness direction of the wiper blade and the direction of the nozzle column. [Figure 5] 2 is an explanatory diagram showing the operation of the head cleaning device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, however, the present invention is not limited to the following embodiments.

[0018] FIG. 1 shows the periphery of a printer head 1 of a DOD-type inkjet printer 100 according to one embodiment of the present invention. The inkjet printer 100 mainly comprises a printer head 1, a head cleaning device 10, and a transport means 20 for transporting a printing medium A. Although not shown in FIG. 1, the inkjet printer 100 also comprises a controller and an ink reservoir. The head cleaning device 10 is used to clean the nozzle arrangement surface 13a of the printer head 1. In the example of FIG. 1, a roll-shaped printing medium A is transported by transport means 20 consisting of a belt conveyor, but the inkjet printer 100 is not limited to this and also includes printers that deliver boxes, sheet-shaped printing mediums, etc. using known conveyors.

[0019] As shown in Figure 4(b), the printer head 1 comprises a hollow rectangular parallelepiped casing 12 and a head main body 13 housed within the casing 12. The head main body 13 has a nozzle arrangement surface 13a on its bottom end surface, and the bottom surface 121 of the casing 12 has nozzle windows 121a. The nozzle arrangement surface 13a protrudes slightly downward from the bottom surface 121. The nozzle arrangement surface 13a is exposed from the casing 12 so as to be housed in the nozzle windows 121a in the bottom surface 121 of the casing 12.

[0020] The printer head 1 is moved by a mechanism (not shown) between a printing position R1, shown by a two-dot chain line in FIG. 1, for printing, and a cleaning position R2, shown by a solid line.

[0021] Reference numeral 11 denotes a composite pipe that houses an air hose that supplies compressed air to the printer head 1 for printing and ink purging, and electrical wiring that supplies power and electrical signals for operating the printer head 1.

[0022] As shown in Figure 4(c), the nozzle arrangement surface 13a of the printer head 1 is an elongated rectangle when viewed from the bottom, and has a large number of nozzles 1a, 1a, ... for ejecting ink lined up in the length direction (left and right direction in Figure 4(c), "vertical column direction" in the claims) at the center of the width direction (up and down direction in Figure 4(c)).

[0023] As shown in Figures 1 and 5, the head cleaning device 10 mainly comprises a wiper blade 2, a wiping roll (wiping member) 4, an ink pan 5, and a purging means (not shown) that purges ink from the nozzles 1a, 1a, ...

[0024] As shown in FIG. 2, the wiper blade 2 is formed into a plate shape from rubber or resin that is resistant to the ink used, and is clamped between a pair of front and rear clamping members 21, 22 and supported by a support arm 33. Reference numerals 2b, 2b denote through holes through which screws pass that connect the clamping members 21, 22. The support arm 33 is directly or indirectly connected to a sliding base 32 that runs along a rail 31 provided in the wiper blade operating unit 3 shown in FIG. 1. For convenience, the structure connecting the sliding base 32 and the support arm 33 is not shown.

[0025] It is sufficient that at least a portion of the tip of the wiper blade 2 is plate-shaped. It is also preferable that the tip 2a of the wiper blade 2 is linear and parallel to the nozzle arrangement surface 13a when viewed in the thickness direction, but even in this case, the overall shape is not limited to a rectangle.

[0026] 4(c), the wiper blade 2 is clamped by clamping members 21 and 22 so that its plate thickness direction is oriented in the vertical direction of the nozzles 1a, 1a, ..., and is configured so that the tip 2a or its vicinity is in contact with the nozzle arrangement surface 13a as the sliding base 32 travels along the rail 31, sliding in the vertical direction to wipe the nozzle arrangement surface 13a. Differences in wiping effect due to the hardness and thickness of the resin or rubber used in the wiper blade 2 can be optimized by adjusting the rearward tilt angle of the wiper blade 2 with respect to the vertical direction and the contact area between the wiper blade 2 and the nozzle arrangement surface 13a. However, the angle θ (see FIG. 4(d)) between the thickness direction S1 of the wiper blade 2 and the nozzle column direction S2 is not limited to 0 degrees as in the illustrated example, but may be any angle of 45 degrees or less.

[0027] In addition, the wiper blade 2 is configured to wipe the nozzle arrangement surface 13a with the tip side (upper side in Figure 4(a)) of the side wiping the nozzle arrangement surface 13a inclined toward the rear side (right side in Figure 4(a)) in the wiping direction (left-right direction in Figure 4(a)).

[0028] The wiper blade 2 is made of a flexible resin or rubber so that it has an appropriate flexibility to bend when it comes into contact with the nozzle arrangement surface 13a and not to damage the nozzle arrangement surface 13a during this sliding movement.

[0029] The sliding base 32 is configured to travel along the rail 31 and to rise and fall at appropriate positions by a mechanism (not shown). As a result, the wiper blade 2 is configured to slide and rise and fall between a standby position P1, a sliding preparation position P2, a wiping start position P3, a wiping end position P4, a return preparation position P5, and a cleaning position P6, as shown in FIG. 4(a).

[0030] As shown in Fig. 3, the wiping roll (wiping member) 4 is formed in a cylindrical shape with an axial hole 4a penetrating in the axial direction, and rotates around a rotation shaft 41 fitted into the axial hole 4a. As shown in Figs. 4(a) and 4(c), the wiping roll 4 is provided on an extension of the longitudinal direction of the nozzles 1a, ... outside the nozzle arrangement surface 13a, and the direction of the rotation shaft 41 is perpendicular to the longitudinal direction of the nozzles 1a, .... Reference numeral 42 denotes a fixing member that fits into the tip end 41a of the rotation shaft 41 to prevent the wiping roll 4 from falling off. However, the wiping roll 4 may be cylindrical.

[0031] The wiping roll 4 is preferably made of an open-cell foamed resin or foamed rubber that can remove or absorb ink adhering to the wiper blade 2 and is resistant to the ink used.

[0032] 1, the ink pan 5 is shaped like a roughly rectangular parallelepiped box that opens upward, and its longitudinal direction is aligned with the longitudinal direction of the nozzles 1a, .... It is positioned so that the nozzle arrangement surface 13a of the printer head 1 at cleaning position R2 and the wiping roll 4 are housed within the opening edge 5a in a plan view. The bottom of the ink pan 5 is inclined so that one end (the right side in FIG. 1) having a drain pipe (not shown) is lower.

[0033] When using ink that cures under ultraviolet light in the inkjet printer 100, a light-shielding chamber 6 (see the two-dot chain line in Figure 1) is provided using a case made of a light-shielding plate or a light-shielding sheet, etc., to completely cover the space where the ink is exposed, including the printer head 1 and the wiper blade 2 of the cleaning device 10, the wiping roll 4, and the ink pan 5.

[0034] (Actions and Effects) Next, the procedure for cleaning the nozzle arrangement surface 13a using the head cleaning device 10 and the actions and effects of each component will be described.

[0035] When cleaning the nozzle arrangement surface 13a, first, as shown in Figure 5(a), the printer head 1 is moved from the printing position R1 above the printing object A to the cleaning position R2 above the ink pan 5, and then, as shown in Figure 5(b), ink is purged from the nozzles 1a, ... into the ink pan 5. This not only prevents the nozzles 1a from clogging, but also serves as a lubricant when the ink adhering to the nozzle arrangement surface 13a is wiped away by the wiper blade 2, preventing the wiper blade 2 from damaging the nozzle arrangement surface 13a.

[0036] Furthermore, the waste ink purged into the ink pan 5 is discharged from a drain pipe (not shown), so there is no need for disposable members to absorb and dispose of the ink.

[0037] After the ink has been purged, as shown in FIG. 5(c), the wiper blade 2 is moved from the standby position P1 to the sliding preparation position P2 and then raised to the wiping start position P3, so that the tip 2a of the wiper blade 2 abuts against the nozzle arrangement surface 13a. In this state, the wiper blade 2 is slid in the direction of the vertical row of nozzles on the nozzle arrangement surface 13a to wipe away ink, solidified ink, paper dust, etc. adhering to the nozzle arrangement surface 13a. At this time, the thickness direction of the wiper blade 2 is oriented in the direction of the vertical row of nozzles 1a, so that the wiper blade 2 can be used without changing its width even if the length of the row of nozzles 1a varies depending on the model of inkjet printer 100.

[0038] Furthermore, because the upper end of the wiper blade 2 is inclined toward the rear side in the wiping direction (the right side in FIG. 5), it is possible to prevent the upper end of the wiper blade 2 from getting caught on the nozzle arrangement surface. Furthermore, because the wiper blade 2 is flexible, when wiping the nozzle arrangement surface 13a, the vicinity of the tip 2a of the surface on the front side in the wiping direction that is curved backward is pressed against the nozzle arrangement surface 13a due to its elasticity, so the nozzle arrangement surface 13a can be wiped efficiently. Ink wiped from the nozzle arrangement surface 13a by the wiper blade 2 falls into the ink pan 5.

[0039] When the wiper blade 2 slides from the wiping start position P3 to the wiping end position P4 and completes wiping of the nozzle arrangement surface 13a, the wiper blade 2 descends to the return preparation position P5 and then moves to the cleaning position P6.

[0040] When the wiper blade 2 moves to the cleaning position P6, the vicinity of the tip 2a of the wiper blade 2 comes into contact with the outer peripheral surface of the wiping roll 4, and in response, the wiping roll 4 rotates on the rotary shaft 41, causing the wiping roll 4 to wipe away ink adhering to the wiper blade 2. Because the wiping roll 4 is made of foam resin or rubber, it can be washed and reused, reducing the need for disposable parts. Because the width direction of the wiping roll 4 is perpendicular to the vertical direction of the nozzles 1a,..., it can be used in common with models with nozzles 1a,... of different lengths.

[0041] Although not specifically described, the operations of the above-mentioned components are controlled by a control unit (not shown).

[0042] (Other embodiments) As described above, the head cleaning device of the present invention is not limited to the above-described embodiment. For example, ink purging may be performed after wiping the nozzle arrangement surface rather than before wiping with the wiper blade. An ink pan or ink wiping member may be omitted. The wiping roller may be provided so that its rotation axis is parallel to or inclined toward the nozzle column direction. The tip of the wiper blade does not need to be inclined backward in the wiping direction. [Explanation of symbols]

[0043] 100 inkjet printers 10 Head cleaning device 1 printer head 11 Nozzle arrangement surface 2 wiper blades 2a tip 4 Wiping material (wiping roll) 5 ink pan

Claims

1. A head cleaning device for a drop-on-demand (DOD) inkjet printer, which uses a wiper blade to wipe a nozzle arrangement surface on which a large number of nozzles are arranged in a vertical row, The head cleaning device is characterized in that the wiper blade is plate-shaped and slides in a thickness direction along the longitudinal direction to wipe the nozzle arrangement surface.

2. 2. The head cleaning device according to claim 1, wherein the tip of the wiper blade is provided in a straight line parallel to the nozzle arrangement surface when viewed in the thickness direction.

3. 2. The head cleaning device according to claim 1, wherein the wiper blade is flexible and configured to wipe the nozzle arrangement surface with a tip thereof inclined rearward in the wiping direction.

4. 3. The head cleaning device according to claim 1, wherein the nozzle arrangement surface is oriented downward, and after ink is purged from the nozzles, the nozzle arrangement surface is wiped by the wiper blade.

5. 5. The head cleaning device according to claim 4, further comprising an ink pan for receiving ink purged from the nozzles.

6. 3. The head cleaning device according to claim 1, further comprising a wiping member that wipes off ink adhering to the wiper blade.

7. The head cleaning device according to claim 6, wherein the wiping member is a columnar or cylindrical wiping roll provided on an extension of the column direction outside the nozzle arrangement surface and having a rotation axis perpendicular to the column direction.

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