Nozzle surface recovery device, droplet ejection head, and inkjet printer

Abstract

To provide a position adjustment mechanism of a guided member to improve positioning accuracy of a nozzle surface recovery device.SOLUTION: A nozzle surface recovery device 200 has: caps 240 which are attached to a nozzle surface of a droplet discharge head 100 having the nozzle surface formed with multiple nozzles 104 for discharging droplets; and guided members (first rollers 220 and second rollers 230) which are guided by guide members (guide rails 280, 290) and moves along the guide members relative to the droplet discharge head 100 to be in a capping position where capping of the nozzle surface may be performed and a retreat position. The nozzle surface recovery device 200 has first position adjustment mechanisms (first adjustment plates 221) each of which moves the guided member in a manner that enables adjustment of relative heights of the nozzle surface and the cap.SELECTED DRAWING: Figure 7A

Description

[Technical Field]

[0001] The present invention relates to a nozzle surface recovery device, a droplet ejection head, and an inkjet printer. [Background technology]

[0002] An inkjet printer, which is a device that ejects liquid, has multiple droplet ejection units (C, M, Y, K) that eject ink and face a transport drum or transport belt that transports a recording medium (Fig. 1 of Patent Document 1, Fig. 7 of Patent Document 2). These droplet ejection units are equipped with multiple droplet ejection heads that make up a line head, and a nozzle surface recovery device keeps the nozzle surface of each droplet ejection head in good condition at all times to prevent clogging and other problems from occurring over time.

[0003] Figure 10 shows the nozzle surface restoration device C disclosed in Patent Document 2 in a retracted position. This nozzle surface restoration device C is normally retracted to the front side of the conveyor belt B, as shown in Figure 10. When performing a restoration process on the nozzle surface, the droplet discharge unit H is raised in the A1 direction, and then the nozzle surface restoration device C is slid in the A2 direction and positioned below the droplet discharge unit H (a position where capping is possible). In this state, the droplet discharge unit H is lowered slightly so that the nozzle surface of the droplet discharge unit H is pressed against the cap of the nozzle surface restoration device C, and a restoration process (cleaning) is performed. Summary of the Invention [Problem to be solved by the invention]

[0004] The nozzle surface of the droplet discharge unit H is positioned with high precision. In contrast, if the positioning precision of the nozzle surface restoration device C during the restoration process is low, capping of the nozzle surface will be incomplete, hindering the restoration process. Conventionally, the sliding movement of the nozzle surface restoration device C was achieved by guiding pins Pn, which served as guided members protruding from the side of the nozzle surface restoration device C, using guide grooves provided in the guide plate (Figure 11 of Patent Document 2). For this reason, it was difficult to achieve high positioning precision for the nozzle surface restoration device C due to dimensional errors between parts.

[0005] The present invention has been made in view of the above circumstances, and has an object to improve the positioning accuracy of the nozzle surface recovery device by providing a position adjustment mechanism for the guided member. [Means for solving the problem]

[0006] In order to solve the above problem, the nozzle surface recovery device of the present invention has a cap that is attached to the nozzle surface of a droplet ejection head having a nozzle surface on which a plurality of nozzles that eject droplets are formed, and a guided member that is guided by a guide member, and the nozzle surface recovery device adopts a capping position and a retracted position for the nozzle surface by moving along the guide member relative to the droplet ejection head, and is characterized in that it has a first position adjustment mechanism that moves the guided member so that the relative height between the nozzle surface and the cap can be adjusted. [Effects of the Invention]

[0007] According to the present invention, the positioning accuracy of the nozzle surface recovery device can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of an inkjet printer according to the present invention. [Figure 2] FIG. 2 is a plan view of the droplet ejection unit as viewed from the opposite side to the nozzle surface. [Figure 3] FIG. 2 is a plan view of the droplet ejection unit as viewed from the nozzle surface side. [Figure 4] FIG. [Figure 5A] FIG. 2 is a perspective view of a nozzle surface recovery device. [Figure 5B] FIG. 2 is a simplified plan view of a nozzle surface recovery device. [Figure 5C] FIG. 2 is a simplified front view of the nozzle surface recovery device. [Figure 6A] FIG. 10 is a perspective view of a state in which the nozzle surface recovery device has been moved below the droplet discharge unit. [Figure 6B] FIG. 10 is a front view of the state in which the nozzle surface recovery device has been moved below the droplet discharge unit. [Figure 7A] FIG. 10 is a perspective view of a first position adjustment mechanism for a roller used in the nozzle surface recovery device. [Figure 7B] FIG. 10 is an exploded perspective view of a first position adjustment mechanism for a roller used in the nozzle surface recovery device. [Figure 8A] FIG. 10 is a perspective view of a second position adjustment mechanism for a roller used in the nozzle surface recovery device. [Figure 8B] FIG. 10 is a plan view of a second position adjustment mechanism for a roller used in the nozzle surface recovery device. [Figure 9A] 1A and 1B are a perspective view and a front view, respectively, of a droplet discharge unit at a lowered position and a nozzle surface recovery device at a retracted position. [Figure 9B] 1A and 1B are a perspective view and a front view, respectively, of a droplet discharge unit at a raised position and a nozzle surface recovery device at a retracted position. [Figure 9C] 1A and 1B are a perspective view and a front view, respectively, of a droplet ejection unit in a raised position and a nozzle surface recovery device in a capping position. [Figure 9D] 10 is a diagram showing the relationship between the rotation angle of the first adjustment plate and the displacement amount of the first roller. FIG. [Figure 10] FIG. 10 is a perspective view of a conventional droplet ejection unit and a nozzle surface recovery device. DETAILED DESCRIPTION OF THE INVENTION

[0009] (● Inkjet printer) Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a schematic diagram of a line head type inkjet printer 1 as a device for ejecting liquid. The inkjet printer 1 includes a carry-in section 10 for carrying in a sheet material P as an application target (recording medium) to which the liquid is applied, a pre-processing section 20, a printing section 30, a drying section 40, an unloading section 50, and a reversing mechanism section 60.

[0010] In the inkjet printer 1, a pretreatment liquid is applied (coated) as needed to a sheet material P carried in (supplied) from a carry-in unit 10 in a pretreatment unit 20, which is a pretreatment means. After that, a liquid is applied in a printing unit 30 to perform the required printing, and after the liquid adhering to the sheet material P is dried in a drying unit 40, the sheet material P is discharged to a carry-out unit 50.

[0011] The carry-in section 10 includes an input tray 11 (lower input tray 11A, upper input tray 11B) that stores a plurality of sheet materials P, and a feeding device 12 (12A, 12B) that separates and sends out the sheet materials P one by one from the input tray 11. The sheet materials P are supplied from the carry-in section 10 to a pre-processing section 20. The pre-processing section 20 includes an application section 21, which is a treatment liquid application means that applies a treatment liquid to the printing surface of the sheet material P, for example, by agglomerating the coloring material of the ink and preventing show-through.

[0012] The printing unit 30 includes a transport drum 31, which is a support member (rotating body) that rotates while supporting the sheet material P on its peripheral surface, and a droplet discharge unit 32 that discharges liquid toward the sheet material P supported on the transport drum 31. The printing unit 30 also includes a transfer drum 34 that receives the sheet material P sent from the pre-processing unit 20 and transfers the sheet material P between it and the transport drum 31, and a transfer drum 35 that receives the sheet material P transported by the transport drum 31 and transfers it to the drying unit 40.

[0013] The sheet material P transported from the pre-processing section 20 to the printing section 30 has its leading edge gripped by a gripping means (sheet gripper) provided on the transfer drum 34, and is transported as the transfer drum 34 rotates. The sheet material P transported by the transfer drum 34 is delivered to the transport drum 31 at a position opposite the transport drum 31.

[0014] Gripping means (sheet grippers) are also provided on the surface of the transport drum 31, and the leading edge of the sheet material P is gripped by the gripping means (sheet grippers). A plurality of suction holes are formed dispersedly on the surface of the transport drum 31, and the suction means generates a suction airflow that flows inward from required suction holes of the transport drum 31. The sheet material P transferred from the transfer drum 34 to the transport drum 31 has its leading edge gripped by the sheet grippers, and is adsorbed and held on the transport drum 31 by the suction airflow of the suction means, and is transported as the transport drum 31 rotates.

[0015] The droplet discharge section 32 is provided with four droplet discharge units 33 (33A to 33D) that discharge droplets. These droplet discharge units 33 (33A to 33D) are radially arranged along the upper outer periphery of the transport drum 31 at equal intervals and symmetrically in FIG.

[0016] The droplet discharge unit 33A can discharge cyan (C) liquid, the droplet discharge unit 33B can discharge magenta (M) liquid, the droplet discharge unit 33C can discharge yellow (Y) liquid, and the droplet discharge unit 33D can discharge black (K) liquid. In addition, droplet discharge units that discharge special liquids such as white and gold (silver) liquid can also be used.

[0017] The ejection operation of each droplet ejection unit 33 of the droplet ejection section 32 is controlled by a drive signal corresponding to the printing information. When the sheet material P carried on the transport drum 31 passes through an area facing the droplet ejection section 32, liquid of each color is ejected from the ejection unit 33, and an image corresponding to the printing information is printed.

[0018] The sheet material P to which the liquid has been applied by the droplet discharge unit 32 is delivered from the transport drum 31 to the delivery drum 35, and the sheet material P received by the delivery drum 35 is delivered to the transport mechanism unit 41 and transferred to the drying unit (heating unit) 40. The drying unit 40 dries the liquid that has been applied to the sheet material P in the printing unit 30. This causes the water content and other liquid components in the liquid to evaporate, the colorant contained in the liquid to be fixed on the sheet material P, and curling of the sheet material P is suppressed.

[0019] The reversing mechanism 60 is a mechanism that reverses the sheet material P by a switchback method when performing double-sided printing on the sheet material P that has passed through the drying unit 40. The reversed sheet material P is sent back upstream of the transfer drum 34 through the conveying path 61 of the printing unit 30.

[0020] The discharge section 50 includes a discharge tray 51 on which a plurality of sheet materials P are stacked, and a sheet conveying device 502. The sheet materials P conveyed through the reversing mechanism section 60 are sequentially stacked and held on the stack section 501.

[0021] (● Droplet ejection unit) Next, we will further explain the droplet discharge unit 33. Fig. 2 is a plan view of the droplet discharge unit 33 as seen from the nozzle surface side, Fig. 3 is a plan view of the droplet discharge unit 33 as seen from the opposite side to the nozzle surface, and Fig. 4 is a diagram showing a plurality of droplet discharge units 33 arranged on the outer periphery of the transport drum 31.

[0022] The droplet discharge unit 33 has a plurality of heads 100 that discharge liquid arranged in a staggered pattern on a head mounting member 302 (line head system). One of the rows of the staggered heads 100 is referred to as head row 100A, and the other row is referred to as head row 100B. The present invention is also applicable to cases where the head mounting member 302 is provided with a single head row rather than a staggered arrangement.

[0023] The head 100 has multiple nozzle rows (two rows are used in this example, but the number is not limited to two) in which multiple nozzles 104 for ejecting liquid are arranged. Here, the "head for ejecting liquid" refers to a functional component that ejects and sprays liquid from the nozzles. The ejected liquid is not particularly limited as long as it has a viscosity and surface tension that allows it to be ejected from the head, but it is preferable that the viscosity of the liquid be 30 mPa s or less at room temperature and normal pressure, or by heating or cooling.

[0024] More specifically, these include solutions, suspensions, emulsions, etc. containing solvents such as water or organic solvents, colorants such as dyes or pigments, functionalizing materials such as polymerizable compounds, resins, surfactants, etc., biocompatible materials such as DNA, amino acids, proteins, calcium, etc., edible materials such as natural dyes, etc., and these can be used for applications such as inkjet inks, surface treatment solutions, liquids for forming components of electronic elements or light-emitting elements or electronic circuit resist patterns, liquid materials for 3D modeling, etc. These include those that use, as energy generation sources for ejecting liquids, piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators using electrothermal conversion elements such as heating resistors, electrostatic actuators consisting of a diaphragm and an opposing electrode, etc.

[0025] In this application, a "liquid ejecting device" is a device that includes a liquid ejection head or a liquid ejection unit and ejects liquid by driving the liquid ejection head. Liquid ejecting devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0026] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0027] For example, examples of "liquid ejecting devices" include image forming devices that eject ink to form images on paper, and three-dimensional modeling devices (three-dimensional modeling devices) that eject modeling liquid onto a powder layer formed from layers of powder in order to create a three-dimensional object (a three-dimensional model).

[0028] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0029] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects onto which a liquid can adhere.

[0030] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics.

[0031] The "liquid" is not particularly limited as long as it has a viscosity and surface tension that allows it to be ejected from a head, but it is preferably one whose viscosity is 30 mPa·s or less at room temperature and normal pressure, or upon heating or cooling. More specifically, it is a solution, suspension, emulsion, etc. containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, or an edible material such as a natural colorant. These can be used, for example, as inkjet inks, surface treatment liquids, liquids for forming components of electronic devices or light-emitting elements, or electronic circuit resist patterns, and material liquids for 3D modeling.

[0032] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0033] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0034] (●Nozzle surface recovery device) Next, a nozzle surface recovery device 200 according to an embodiment of the present invention will be described with reference to Figures 4 to 9. As shown in Figure 4, the nozzle surface recovery device 200 is configured to be able to be inserted into the gap between the droplet discharge unit 33 and the outer peripheral surface of the transport drum 31 by moving in the axial direction of the transport drum 31 (the front-to-rear direction on the plane of Figure 4).

[0035] As shown in Figures 5A to 5C, the nozzle surface recovery device 200 has an elongated rectangular substrate 210, a plurality of caps 240 that are attached to the nozzle surfaces of the droplet ejection units 33, and a wiper 250 and a web 260 that wipe the nozzles of the droplet ejection units 33.

[0036] The multiple caps 240 are arranged in the same number as the nozzle faces of the droplet discharge units 33. As shown in Fig. 3, the nozzle faces of the droplet discharge units 33 are arranged in a staggered pattern with two adjacent faces in two rows at six locations in each head 100, and similar to this staggered arrangement, the caps 240 are also arranged in pairs in two rows at six locations in a staggered pattern.

[0037] Each cap 240 is connected to a waste liquid tank via a waste liquid pump. With the cap 240 attached to the nozzle surface of the droplet ejection unit 33, ink is ejected from the nozzles into the cap 240 to clean the nozzles from clogging, etc. The ejected ink is sent to the waste liquid tank via the waste liquid pump.

[0038] The wipers 250 are made up of a pair of left and right elastic plates that stand vertically on the base plate 210. These wipers 250 are arranged in two rows at six positions on the front end side of the cap 240.

[0039] The webs 260 are made of a liquid-absorbent nonwoven fabric or the like and are arranged in pairs on the left and right sides of the substrate 210. These webs 260 are arranged in front of the wiper 250.

[0040] Both sides (long sides) of the base plate 210 are bent upward in an L-shape to form a pair of vertical side plate portions 211. One of the side plate portions 211 has a portion of both longitudinal ends cut horizontally outward to form a bracket portion 212.

[0041] First rollers 220 for supporting the nozzle surface recovery device 200 in the height direction are journaled on both longitudinal ends of the left and right side plate portions 211. Furthermore, a rotation shaft 231 of a second roller 230 for supporting the nozzle surface recovery device 200 in the left and right direction is journaled on the bracket portion 212 of one of the side plate portions 211. The first rollers 220 and the second rollers 230 constitute guided members that are guided by guide rails 280 and 290, which will be described later.

[0042] The first roller 220 and the second roller 230 are configured to be able to roll along a pair of left and right guide rails 280, 290 that serve as guide members shown in Figures 6A and 6B. The guide rails 280, 290 are fixed to the machine frame of the printing unit 30 shown in Figure 1. The longitudinal direction of the guide rails 280, 290 is parallel to the axial direction of the transport drum 31 (the front-to-rear direction on the paper surface of Figure 4). The nozzle surface recovery device 200 is configured to be able to move back and forth along the pair of left and right guide rails 280, 290.

[0043] 5B and 5C, the first roller 220 is configured to be able to roll on the horizontal bottom plate portions of the left and right guide rails 280, 290 having an L-shaped cross section, and the second roller 230 is configured to be able to roll on the inner surface of the vertical side plate portion of one of the guide rails 290. Note that the wiper 250 and web 260 are omitted from FIGS. 5B and 5C.

[0044] 5B and 5C, a leaf spring 270 that comes into sliding contact with an inner surface 281 of the vertical side plate portion of the guide rail 280 can be attached to the outer surface of the side plate portion 211 opposite the second roller 230, as needed. By elastically pressing the inner surface 281 of the vertical side plate portion of the guide rail 280 with the tip of the leaf spring 270, it is possible to prevent the second roller 230 from lifting up from the guide rail 290, regardless of the tilt direction of the nozzle surface recovery device 200 in FIG.

[0045] 4, if the second roller 230 of the nozzle surface recovery device 200 is disposed on one side in the direction of gravity, the second roller 230 can be pressed against the guide rail 290 by the weight of the nozzle surface recovery device 200, even without the leaf spring 270. This allows the positional deviation of the cap 240 in the direction parallel to the nozzle surface of the droplet discharge unit 33 and perpendicular to the guide rails 280, 290 to be accurately adjusted by the second adjustment plate 232 of the second position adjustment mechanism, which will be described later.

[0046] 6A and 6B, the nozzle surface recovery device 200 is disposed so that the upper end position of the cap 240 of the nozzle surface recovery device 200 precisely matches the position of the nozzle surface (lower surface) of the droplet discharge unit 33 that has been raised in the height direction. This makes it possible to attach the cap 240 of the nozzle surface recovery device 200 to the nozzle surface of the droplet discharge unit 33 without any gaps by moving the nozzle surface recovery device 200 in the A5 direction in Fig. 6A. The alignment of the cap 240 and the nozzle surface is performed by first and second position adjustment mechanisms, which will be described later.

[0047] The upper end positions of the wiper 250 and the web 260 are set to a position slightly higher than the upper end position of the cap 240. This allows the web 260 and the wiper 250 to wipe the multiple nozzle surfaces of the droplet discharge unit 33 when the nozzle surface recovery device 200 is moved from the retracted position to the capping position as shown in Figures 9B and 9C, which will be described later.

[0048] (● First position adjustment mechanism) 5A and 5B, the positions of the first rollers 220 disposed at the four corners (front, back, left, and right) of the nozzle surface recovery device 200 can be adjusted in the height direction (direction A3) by a first position adjustment mechanism, as shown in FIGS. 7A and 7B. More specifically, an eccentric shaft 220a integrally connected to the rotation shaft of the first roller 220 is fitted into a shaft hole 211b formed in the side plate portion 211 of the substrate 210. The axis of the rotation shaft of the first roller 220 is eccentric by a predetermined distance with respect to the axis of this eccentric shaft 220a.

[0049] The end of the eccentric shaft 220a opposite to the first roller 220 is D-cut to prevent rotation and couple with the fan-shaped first adjusting plate 221. The D-cut eccentric shaft 220a is inserted into and coupled with the D-shaped shaft hole 221a of the first adjusting plate 221.

[0050] An arc-shaped elongated hole 221b centered on the shaft hole 221a is formed in the arc portion of the fan-shaped first adjustment plate 221. By inserting a fixing screw 222 into this elongated hole 221b and screwing it into a screw hole 211c in the side plate portion 211, the rotation position of the first adjustment plate 221 around the eccentric shaft 220a can be fixed.

[0051] Arc-shaped adjustment scale 211a is engraved or printed on the inner surface of side plate portion 211 along the arc portion of first adjustment plate 221. Meanwhile, triangular mark 221c is provided on the arc portion of first adjustment plate 221, and the rotational position of first adjustment plate 221 can be confirmed by the position of adjustment scale 211a indicated by triangular mark 221c.

[0052] Because the eccentric shaft 220a is eccentric with respect to the rotation axis (axial center) of the first roller 220, the height position of the first roller 220 in the A3 direction in Fig. 7A can be checked and adjusted by rotating the eccentric shaft 220a or the first adjustment plate 221. In other words, the first adjustment plate 221 constitutes a first position adjustment mechanism that moves the first roller 220 as a guided member so as to adjust the relative height between the nozzle surface and the cap 240.

[0053] (● Second position adjustment mechanism) The rotation shaft of the second roller 230 described above is directly journaled on the bracket portion 212 as explained in Fig. 5A, or can be supported so that its position can be adjusted in the lateral direction (A4 direction) by a second position adjustment mechanism having a second adjustment plate 232 as shown in Figs. 8A and 8B. More specifically, a second adjustment plate 232 is provided in place of the bracket portion 212 of the side plate portion 211 of the base plate 210, and the rotation shaft 231 of the second roller 230 is journaled on this second adjustment plate 232. A part of the outer periphery of the second roller 230 protrudes outside the base plate 210 from a notch 211d formed in the side plate portion 211 and abuts against the inner surface of the vertical side plate portion of the guide rail 290.

[0054] The second adjusting plate 232 has a pair of elongated holes 232a and a linear inclined portion 232b. The second adjusting plate 232 can be fixed to the substrate 210 by passing screws 234 through the pair of elongated holes 232a and fastening it to the substrate 210.

[0055] The inclined portion 232b is inclined with respect to the movement direction of the nozzle surface recovery device 200 (the up and down direction in FIG. 8B). The direction of this inclination may be reversed. Meanwhile, a pair of guide pins 233 are fixedly disposed on the substrate 210. Then, with the screws 234 loosened, the inclined portion 232b of the second adjustment plate 232 slides on the pair of guide pins 233, so that the second adjustment plate 232 can move in the direction of the inclined portion 232b.

[0056] An adjustment scale 210a is engraved or printed on the surface of the substrate 210 between the pair of guide pins 233. Meanwhile, a triangular mark 232c is provided at the center of the longitudinal direction of the inclined portion 232b of the second adjustment plate 232.

[0057] The position of adjustment scale 210a indicated by this triangular mark 232c makes it possible to check and adjust the slide position of second adjustment plate 232, and therefore the A4 direction position of second roller 230. In other words, second adjustment plate 232 constitutes a second position adjustment mechanism that moves second roller 230, which serves as a guided member, so as to adjust the positional deviation of cap 240 in a direction parallel to the nozzle surface and perpendicular to guide rails 280, 290.

[0058] (● Nozzle surface recovery treatment) The nozzle surface recovery device 200 is configured as described above, and is used to recover (clean) the nozzle surface of the droplet discharge unit 33. The recovery process is performed as follows.

[0059] 9A(a) and 9A(b), the nozzle surface recovery device 200 is moved to a retracted position at the end of the guide rails 280 and 290. At this retracted position, the nozzle surface recovery device 200 is removed from the gap between the droplet discharge unit 33 and the transport drum 31 to the front side in the axial direction of the transport drum 31.

[0060] 9A(a) and (b), the liquid (ink) is ejected from the nozzles of the droplet ejection unit 33 toward the recording medium held on the outer circumferential surface of the transport drum 31 to perform the required printing. The distance between the nozzle surface recovery device 200 in the retracted position and the droplet ejection unit 33 may be kept to the minimum necessary to minimize the guide rails 280 and 290 and make the nozzle surface recovery device 200 smaller.

[0061] 9B(a)(b), the droplet discharge unit 33 is first raised upward (in the direction of A6) by the lifting mechanism. This lifting operation is performed to form a space between the droplet discharge unit 33 and the outer peripheral surface of the transport drum 31 into which the nozzle surface recovery device 200 can be inserted.

[0062] After the droplet discharge unit 33 has been raised, the nozzle surface recovery device 200 is advanced (slid) in the A7 direction toward the space formed between the droplet discharge unit 33 and the outer circumferential surface of the transport drum 31. At this time, the distance the nozzle surface recovery device 200 is advanced is approximately the length of the nozzle surface recovery device 200 in the advancement direction. While the nozzle surface recovery device 200 is advanced, the web 260 and the wiper 250 can be used to preliminarily wipe the multiple nozzle surfaces of the droplet discharge unit 33.

[0063] When the forward movement of the nozzle surface recovery device 200 is completed, the droplet discharge unit 33 is slightly lowered in the direction A8 as shown in Figures 9C(a) and 9C(b). This allows the caps 240 of the nozzle surface recovery device 200 to be attached to each nozzle face of the droplet discharge unit 33 without any gaps.

[0064] The alignment of the nozzle face and the cap 240 can be performed in advance using the first position adjustment mechanism shown in Figures 7A and 7B or the second position adjustment mechanism shown in Figures 8A and 8B. The first rollers 220 arranged at the four corners of the nozzle face recovery device 200 can each be adjusted in height using the first position adjustment mechanism, so that the nozzle face and the cap 240 can be accurately aligned in the height direction. Furthermore, the second rollers 230 arranged on one side of the nozzle face recovery device 200 can each be adjusted in lateral movement using the second position adjustment mechanism, so that the cap 240 can be accurately aligned in the direction parallel to the nozzle face.

[0065] When adjusting the height of first roller 220, the relationship between the rotation angle of first adjustment plate 221 and the displacement of first roller 220 shown in Fig. 9D can be used to smoothly adjust the height. This relationship between the rotation angle and the displacement varies depending on the eccentricity of the rotation axis of first roller 220. As the eccentricity increases, the slope of the curve in Fig. 9D increases.

[0066] The straight line portion in the center of the curve in Figure 9D can be expressed by an approximation (displacement amount = ax rotation angle, a: constant). Therefore, by forming the adjustment scale 211a in a form corresponding to the required movement amount (displacement amount) of the first roller 220, the first roller 220 can be quickly adjusted to the desired movement amount. Similarly, the adjustment scale 210a of the second position adjustment mechanism can also be formed in a form corresponding to the required movement amount (displacement amount) of the second roller 230.

[0067] 9C(a)(b), with the cap 240 attached to the nozzle face of the droplet ejection unit 33, the waste liquid pump connected to the cap 240 is operated and ink is ejected from the nozzles into the cap 240. This allows excess ink and foreign matter on the nozzle face to be sucked out, thereby performing a recovery process (cleaning) of the nozzle face. The ejected ink is sent to a waste liquid tank via the waste liquid pump.

[0068] Once the nozzle surface recovery process is complete, the nozzle surface recovery device 200 is retracted to its original retracted position by reversing the procedure described above. Then, the droplet discharge unit 33 is lowered as shown in Figure 9A and set to a printable state.

[0069] If the printer 1 will not be used for a long period of time, the nozzle surface recovery device 200 is moved forward to the capping position as shown in Figure 9C. Then, a cap 240 is attached to the nozzle surface of the droplet ejection unit 33 to prevent the nozzle surface from drying out.

[0070] While the present invention has been specifically described above based on the embodiments, it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways within the scope of the technical concept set forth in the claims. For example, in the inkjet printer 1 described above, the multiple heads 100 are arranged in a staggered pattern, but it is also possible to arrange multiple heads, each having a plurality of inclined nozzle rows, in a straight line.

[0071] In addition, in the above embodiment, the first roller 220 and the second roller 230 are used as the guided members, but the guided members are not limited to rollers, and guided pins, etc. may also be used. In short, the guided members can be made up of any member that can slide with low friction on the guide rails 280, 290, which are the guide members.

[0072] Furthermore, the first and second position adjustment mechanisms are not limited to the embodiments shown in Figures 7A to 8B. For example, the first roller 220 may be supported by the second adjustment plate 232 as shown in Figures 8A and 8B, or the second roller 230 may be supported by the eccentric shaft 220a as shown in Figures 7A and 7B. In this way, various mechanisms having similar functions can be used as the position adjustment mechanism. [Explanation of symbols]

[0073] 1: Inkjet printer (a device that ejects liquid) 10: Loading section 11: Loading tray 11A: Lower loading tray 1B: Upper loading tray 12 (12A, 12B): Feeding device 20: Pre-processing section 21: Coating section 30: Printing section 31: Conveyor drum 32: Droplet ejection unit 33 (33A to 33D: droplet discharge unit 34: transfer drum 35: Transfer cylinder 40: Drying section (heating section) 41: Transport mechanism section 50: Unloading section 51: Output tray 60: Reversing mechanism 61: Transfer path 100: Head 100A, 100B: Head row 104: Nozzle 200: Nozzle surface recovery device 210: Substrate 210a: Adjustment scale 211: Side plate 211a: Adjustment scale 211b: Shaft hole 211c: Screw hole 211d: Notch 212: bracket portion 220a: eccentric shaft 221: First adjustment plate (first position adjustment mechanism) 221a: Shaft hole 221b: Oblong hole 221c: Triangle mark 222: Fixing screw 231: Rotating shaft 232: Second adjustment plate (second position adjustment mechanism) 232a: Long hole 232b: Inclined portion 232c: Triangle mark 233: Guide pin 234: Screw 240: Cap 250: Wiper 260: Web 270: Leaf spring 280, 290: Guide rail 281: Inner surface of guide rail 302: Head mounting member 501: Stack section 502: Sheet conveying device P: Sheet material (recording medium) B: Conveyor belt H: Droplet ejection unit Pn: pin [Prior art documents] [Patent documents]

[0074] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-51015 [Patent Document 2] Patent No. 4790107

Claims

1. a nozzle surface recovery device that includes a cap that is attached to a nozzle surface of a droplet ejection head having a nozzle surface formed with a plurality of nozzles that eject droplets, and a guided member that is guided by a guide member, and that moves along the guide member relative to the droplet ejection head to take a capping position and a retracted position for the nozzle surface, a first position adjustment mechanism that moves the guided member so as to adjust the relative height between the nozzle surface and the cap; a second position adjustment mechanism that moves the guided member so as to adjust a positional deviation of the cap in a direction parallel to the nozzle surface and perpendicular to the guide member; A nozzle surface recovery device comprising:

2. 2. The nozzle surface recovery device of claim 1, wherein the guided member has first and second rollers that roll along the guide member, the relative height of the nozzle surface and the cap can be adjusted by adjusting the first rollers with the first position adjustment mechanism, and the positional deviation of the cap in a direction parallel to the nozzle surface and perpendicular to the guide member can be adjusted by adjusting the second rollers with the second position adjustment mechanism.

3. 3. The nozzle surface recovery device according to claim 2, wherein the first position adjustment mechanism has an eccentric shaft connected to the rotation shaft of the first roller, and adjusts the relative height of the nozzle surface and the cap by rotating the eccentric shaft.

4. 4. The nozzle surface recovery device according to claim 3, wherein said first position adjustment mechanism has a position adjustment scale indicating the amount of rotation of said eccentric shaft.

5. 3. The nozzle surface recovery device according to claim 2, wherein the second position adjustment mechanism has an adjustment plate that supports the rotation shaft of the second roller and is movable in a direction parallel to the nozzle surface.

6. 6. The nozzle surface recovery device of claim 5, wherein the adjustment plate has an inclined edge that is in sliding contact with at least two guide pins fixed to the nozzle surface recovery device main body, and the adjustment plate moves in the direction of the inclined edge to move the second roller in a direction parallel to the nozzle surface and perpendicular to the guide member.

7. 7. The nozzle surface recovery device according to claim 6, wherein the second position adjustment mechanism has a position adjustment scale that indicates the amount of movement of the adjustment plate.

8. 8. The nozzle surface recovery device according to claim 2, wherein the guide member has two parallel rows of guide rails, and the first rollers are disposed at four locations on the front, rear, left and right sides of the nozzle surface recovery device body.

9. 9. The nozzle surface recovery device according to claim 8, wherein the second rollers are disposed at two locations, one at the front and one at the rear of the nozzle surface recovery device main body, and roll along one of the two parallel rows of guide rails, and an elastic member is disposed between the other of the guide rails and the nozzle surface recovery device main body to urge the second rollers against one of the guide rails.

10. A droplet ejection head comprising the nozzle surface recovery device according to any one of claims 1 to 9.

11. A line head type ink jet printer comprising the droplet ejection head according to claim 10.

12. 12. The inkjet printer according to claim 11, further comprising a transport drum that holds and transports the recording medium on its circumferential surface, and a plurality of the droplet ejection heads and the nozzle surface recovery devices are radially arranged on the outer periphery of the upper portion of the transport drum.

13. Equipped with the nozzle surface recovery device according to claim 2, an ink jet printer, wherein the second roller is disposed on one side, in the direction of gravity, of a plurality of the nozzle surface recovery devices disposed radially;

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