Maintenance equipment and printing system

Abstract

In maintenance equipment and printing systems, wear on the nozzle surface of the inkjet head is suppressed. [Solution] The maintenance device 1 comprises a wiper blade 11, an ink detection sensor S, and a control unit 50. The wiper blade 11 wipes the inkjet head 110 on the nozzle surface 111 where the nozzle 111a that ejects ink IK is provided (steps S7, S8). The ink detection sensor S detects the fall state of the ink IK purged by the nozzle 111a when the nozzle surfaces 111a intersect horizontally (step S6). Based on the fall state detected by the ink detection sensor S, the control unit 50 adjusts the contact pressure of the wiper blade 11 against the nozzle surface 111 (step S7).

Description

Technical Field

[0001] The present invention relates to a maintenance device for wiping an inkjet head and a printing system including this maintenance device.

Background Art

[0002] Conventionally, when performing maintenance on a printer, a method is known in which, in order to remove foreign matter inside and on the nozzle surface of an inkjet head, after purging ink at high pressure, the ink is wiped off by a wiping operation.

[0003] Many inkjet heads discharge ink vertically downward, and the nozzle surface is often wiped in a horizontal state. On the other hand, for an inkjet head that discharges ink in the horizontal direction, the nozzle surface is wiped in a state where the nozzle surface is orthogonal to the horizontal direction (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, since a liquid-repellent film is coated on the nozzle surface of the inkjet head, the ink after discharge does not spread on the nozzle surface. However, if the wiping operation is repeated thousands of times, the liquid-repellent film on the nozzle surface gradually wears out. In a state where the liquid-repellent film is worn out, the ink purged from the nozzle runs down along the nozzle surface in the gravitational direction, and there may be a case of dry wiping (state without ink, dry friction). Then, the frictional force becomes significantly larger than when there is ink, and the wear of the nozzle surface further progresses.

[0006] The object of the present invention is to provide a maintenance device and a printing system that can suppress wear on the nozzle surface of an inkjet head. [Means for solving the problem]

[0007] In one embodiment, the maintenance device includes a wiper blade that wipes the inkjet head over a nozzle surface on which an ink ejection nozzle is provided; an ink detection sensor that detects the state of ink falling after being purged by the nozzle when the nozzle surfaces intersect horizontally; and a control unit that adjusts the contact pressure of the wiper blade against the nozzle surface based on the state of ink falling detected by the ink detection sensor. [Effects of the Invention]

[0008] According to the above embodiment, wear on the nozzle surface of the inkjet head can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view showing a printing system according to one embodiment. [Figure 2] This is a block diagram showing the control configuration of a maintenance device according to one embodiment. [Figure 3A] This is a front view showing an inkjet head and an ink detection sensor in one embodiment. [Figure 3B] This is a left side view showing an inkjet head and ink detection sensor in one embodiment. [Figure 3C] This is a front view showing an inkjet head and an ink detection sensor for illustrating ink detection in one embodiment. [Figure 4A] This is a left side view showing a detection unit to illustrate the OFF state of the ink detection sensor in one embodiment. [Figure 4B] This is a left side view showing a detection unit for illustrating the ON state of the ink detection sensor in one embodiment. [Figure 5]This is a flowchart illustrating the maintenance process in one embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, a maintenance device 1 according to one embodiment of the present invention and a printing system 100 equipped with this maintenance device 1 will be described with reference to the drawings.

[0011] Figure 1 is a front view showing the printing system 100.

[0012] Figure 2 is a block diagram showing the control configuration of the maintenance device 1.

[0013] Note that in Figure 1 and Figures 3A to 4B described later, the front-back, up-down, and left-right directions are mutually orthogonal, the front-back and left-right directions are horizontal, and the up-down direction is vertical. These directions are examples when the ink IK ejection direction D3 (see Figure 3B) of the inkjet head 110 is considered to be forward.

[0014] The printing system 100 shown in Figure 1 comprises a maintenance device 1, eight inkjet heads 110, a head holder 120, and multiple (one in the illustration) ink circulation units 130.

[0015] The maintenance device 1 comprises a wipe mechanism 10, an ink pan 20, a waste liquid tank 30, a waste liquid hose 40, and eight ink detection sensors S. Furthermore, as shown in Figure 2, the maintenance device 1 also comprises a control unit 50, a storage unit 60, a display unit 70, an input unit 80, and an interface unit 90.

[0016] The wiper mechanism 10 includes four wiper blades 11, a wiper base 12, a wiper drive unit 13, a ball screw 14, a pair of left and right guide rails 15, 16, and a base plate 17. The wiper mechanism 10, together with the ink pan 20, is movable between a maintenance position where a wiping operation is performed on the nozzle surface 111 as shown in FIG. 1 and a storage position (for example, a position spaced apart from the inkjet head 110 in the front-rear direction or the left-right direction) not shown. The movement of the wiper mechanism 10 and the ink pan 20 may be performed manually or automatically by a drive unit not shown.

[0017] The wiper blade 11 is made of, for example, a plate-shaped elastic body made of rubber that extends horizontally. The wiper blade 11 extends behind the nozzle surface 111 of the inkjet head 110 (in the direction opposite to the discharge direction D3 shown in FIG. 3B) when the maintenance device 1 is in the above-described maintenance position. Then, the wiper blade 11 contacts the nozzle surface 111 of the inkjet head 110 and wipes the nozzle surface 111 in the wiping direction D1, which is vertically downward, while bending.

[0018] As will be described later, eight inkjet heads 110 are arranged in four rows in the width direction D2 (left-right direction) because two sets of four inkjet heads 110 are arranged in a staggered manner. Therefore, four wiper blades 11 are arranged to wipe the nozzle surfaces 111 of the four rows of inkjet heads 110. The width direction D2 is a direction orthogonal to the wiping direction D1 and the discharge direction D3 in which the nozzles 111a discharge ink IK (inside the pressure tank 131 and the negative pressure tank 132 in FIG. 1, see also FIG. 3C).

[0019] The wiper base 12 extends in the width direction D2 of the wiper blade 11 and holds the four wiper blades 11. A female screw hole (not shown) that meshes with the ball screw 14 described later is formed in the center of the wiper base 12 in the width direction D2.

[0020] The wiper drive unit 13 is an actuator such as a motor that rotates a ball screw 14 extending in the wipe direction D1 (vertical direction). The wiper drive unit 13 is located at the upper end of the ball screw 14. As the wipe base 12 moves up and down due to the rotation of the ball screw 14, the four wiper blades 11 fixed to the wipe base 12 also move up and down. When the maintenance device 1 is in the maintenance position shown in Figure 1, the wiper drive unit 13 moves the wipe mechanism 10 vertically downward in the wipe direction D1 while performing a wipe operation with the wiper blades 11. When the maintenance device 1 is in the storage position described above, it is preferable to move the wiper blades 11 vertically upward in preparation for the next wipe operation.

[0021] The guide rails 15 and 16 extend in the wiping direction D1 (vertical direction) and guide both ends of the wipe base 12 in the width direction D2. For example, the guide rails 15 and 16 have a U-shaped plate that faces each other in a plan view and slidably hold rollers (with their axis of rotation parallel to the width direction D2) provided at both ends of the wipe base 12.

[0022] The base plate 17 is located at the lower end of the guide rails 15 and 16 and extends horizontally. The base plate 17 may have a bearing at its center in the width direction D2 that rotatably supports the lower end of the ball screw 14. As shown in Figure 1, an ink pan 20 may be placed on the base plate 17.

[0023] The ink pan 20 has a rectangular parallelepiped shape with an opening at the top. The ink pan 20 receives ink IK (including foreign matter inside the nozzle 111a and on the nozzle surface 111) that is wiped and falls by the wiper blade 11.

[0024] The waste liquid tank 30 is positioned below the ink pan 20 and contains the ink IK that flows in from the ink pan 20, for example, via a flexible waste liquid hose 40. The waste liquid tank 30 and waste liquid hose 40 may be moved together with the wipe mechanism 10 and the ink pan 20 to a maintenance position and a storage position, but if the waste liquid hose 40 is flexible as described above, it becomes unnecessary to move the waste liquid tank 30.

[0025] Each of the eight ink detection sensors S is fixed to the bottom of the inkjet head 110, as shown in Figures 3A and 3B. The ink detection sensors S are, for example, reflective photoelectric sensors and have a detection unit Sa located below the nozzle surface 111. The ink detection sensors S are used to detect the fall time (an example of the fall state) of the ink IK purged by the nozzle 111a. The ink IK is purged with the nozzle surfaces 111 intersecting horizontally so that the fall time of the ink IK includes the time it travels along the nozzle surface 111.

[0026] The detection unit Sa is a transparent plate material, such as a smooth acrylic plate, and its front surface (the front surface in the discharge direction D3) is on the same plane as the nozzle surface 111. If the nozzle surface 111 is inclined with respect to the vertical direction, the front surface of the detection unit Sa should be located vertically below the lower end of the nozzle surface 111.

[0027] As shown in Figure 4A, when no ink IK is present on the detection unit Sa, the detection light L of the ink detection sensor S passes through the detection unit Sa, and the ink detection sensor S outputs an OFF signal. On the other hand, as shown in Figure 3C, when ink IK purged by the nozzle 111a adheres to the detection unit Sa, as shown in Figure 4B, the detection light L of the ink detection sensor S is reflected by the ink IK, and the ink detection sensor S outputs an ON signal.

[0028] The control unit 50 shown in Figure 2 has a processor (e.g., CPU: Central Processing Unit) that functions as an arithmetic processing unit that controls the operation of the maintenance device 1, and controls the operation of each part of the maintenance device 1. For example, the control unit 50 controls the operation of the wiper drive unit 13 and acquires the ON signal and OFF signal from the ink detection sensor S. As will be described in detail later, the control unit 50 controls the wiper drive unit 13 to adjust the contact pressure (e.g., wipe speed) of the wiper blade 11 against the nozzle surface 111 based on the time from when the nozzle 111a purges the ink IK until the ink detection sensor S outputs an ON signal. Note that the control unit 50 may control the operation of the entire printing system 100. That is, the control unit 50 may not be dedicated to the maintenance device 1, but may be used for the entire printing system 100. Similarly, the storage unit 60, display unit 70, input unit 80, and interface unit 90, which will be described later, may not be dedicated to the maintenance device 1, but may be used for the entire printing system 100.

[0029] The memory unit 60 may include, for example, a ROM (Read Only Memory), which is a read-only semiconductor memory in which a predetermined control program is pre-recorded, or a RAM (Random Access Memory), which is a semiconductor memory that can be written to and read at any time and used as a working memory area as needed when the processor executes various control programs, or a hard disk drive.

[0030] The display unit 70 is a display, lamp, etc., that displays various information. The display unit 70 functions as an example of a notification unit that notifies the user by displaying error messages, messages prompting the replacement of the inkjet head 110, etc. This notification unit may also be an audio output unit that notifies the user by outputting sound, etc.

[0031] The input unit 80 is an operation key, touch panel, or the like that accepts user input information. A single operation panel may function as both the display unit 70 and the input unit 80.

[0032] The interface unit 90 exchanges various types of information with external devices.

[0033] The eight inkjet heads 110 shown in Figure 1 eject ink IK in the forward (horizontal) ejection direction D3 (see Figure 3B) from two rows of nozzles, each consisting of multiple nozzles 111a (only the upper left inkjet head 110 in Figure 1 is shown with a reference numeral) arranged vertically on the front nozzle surface 111. At least during maintenance, the nozzle surfaces 111 intersect horizontally, and the ejection direction D3 becomes different from the vertical direction. For example, the nozzle surface 111 is formed of polyimide resin and coated with a liquid-repellent film.

[0034] Regarding the eight inkjet heads 110, when the material to be printed, such as a cardboard box, is transported in the left-right direction, two sets of four inkjet heads 110 are arranged in a staggered pattern along the vertical direction, for a total of eight heads. That is, the four inkjet heads 110 arranged in the vertical direction are positioned with alternating staggers in the left-right direction. For example, one set of four inkjet heads 110 ejects two inks (IK) of different colors (e.g., black (K) and cyan (C)), while the other set of four inkjet heads 110 ejects two inks (IK) of different colors (e.g., magenta (M) and yellow (Y)). The material to be printed is, for example, a rectangular parallelepiped-shaped three-dimensional object such as the cardboard box, and printing is performed on the side (rear) by the inkjet heads 110. The shape of the material to be printed may be, for example, a plate-like shape that expands vertically, or a sheet-like shape such as paper, when the material to be printed is transported while being held in the front-to-back direction.

[0035] The head holder 120 has holes in the area where the eight inkjet heads 110 are arranged. The eight inkjet heads 110 are fixed to the head holder 120 through these holes. In this way, the head holder 120 holds the eight inkjet heads 110.

[0036] The ink circulation unit 130 includes a pressurized tank 131, a negative pressure tank 132, ink circulation paths 133 and 134, a pressure adjustment mechanism 135, air passages 136 and 137, and an ink pump P. In Figure 1, the ink circulation unit 130 is shown as being connected only to the inkjet head 110 in the lower right, but it is actually arranged for at least one color of ink IK ejected by the inkjet head 110 and connected to each inkjet head 110.

[0037] The pressurized tank 131, the negative pressure tank 132, the ink circulation paths 133 and 134, and the ink pump P are connected to the inkjet head 110 and constitute a circulation channel that supplies ink IK to the inkjet head 110 while circulating the ink IK.

[0038] The pressurized tank 131 stores the ink IK supplied to the inkjet head 110. The pressurized tank 131 is positioned lower than the inkjet head 110. The ink IK from the pressurized tank 131 is supplied to the inkjet head 110 via the ink circulation path 133. The ink IK supplied from the pressurized tank 131 to the inkjet head 110 is then distributed by a distributor (not shown) to multiple inkjet heads 110 that eject ink IK of the same color. The temperature of the ink IK supplied to the inkjet head 110 may be regulated by, for example, a heat sink, cooling fan, heater, etc. An air layer is formed above the liquid surface of the ink IK inside the pressurized tank 131.

[0039] The negative pressure tank 132 stores ink IK that was not consumed by the inkjet head 110. The negative pressure tank 132 is located at the same height as the pressurized tank 131. The negative pressure tank 132 receives ink IK collected by a collector (not shown) from multiple inkjet heads 110 that eject ink IK of the same color, via the ink circulation path 134. The negative pressure tank 132 also receives ink IK from ink supply sources such as ink cartridges. An air layer is formed above the liquid surface of the ink IK inside the negative pressure tank 132.

[0040] The ink pump P supplies ink IK from the negative pressure tank 132 to the pressurized tank 131.

[0041] The pressure adjustment mechanism 135 adjusts the pressure in the pressurized tank 131 and the negative pressure tank 132 via air passages 136 and 137. The pressure adjustment mechanism 135 includes, for example, a pressurized air chamber, a negative pressure air chamber, an atmospheric release valve, and an air pump. The pressure adjustment mechanism 135 can be arranged as a single adjustment mechanism common to multiple ink circulation units 130, as long as it adjusts the pressure of multiple pressurized tanks 131 and multiple negative pressure tanks 132, which are arranged for each color of ink IK, to a common pressure. When the ink IK is purged by the inkjet head 110, the atmospheric release valve of the pressure adjustment mechanism 135 is closed and the air pump is driven in order to generate the set pressure for purging in the pressurized tank 131 and the negative pressure tank 132, respectively. In this way, purging is a process in which ink IK is supplied from the pressurized tank 131 to the inkjet head 110, thereby forcibly expelling the ink IK from the nozzles 111a of each inkjet head 110.

[0042] Next, we will explain the maintenance using the wiper blade 11, referring to the flowchart in Figure 5. Note that explanations that overlap with the above explanation will be omitted as appropriate.

[0043] The maintenance process shown in Figure 5 may be performed by the control unit 50 shown in Figure 2, for example, at predetermined print cycles or elapsed time intervals, when the inkjet head 110 (nozzle 111a) becomes clogged, or based on user operation in the input unit 80 shown in Figure 1.

[0044] First, the control unit 50 determines whether the ink detection sensor S is in the OFF state, outputting an OFF signal (step S1). If, as shown in Figure 4B, ink IK is attached to the detection part Sa of the ink detection sensor S before maintenance and the ink detection sensor S is outputting an ON signal (step S1: NO), the control unit 50 cannot obtain the ink IK fall time (fall state), which will be described later. Therefore, the control unit 50 stops the operation of the maintenance device 1 (printing system 100) (step S2), notifies the user of the error by displaying it on the display unit 70, etc. (step S3), and the process shown in Figure 5 is completed.

[0045] As shown in Figure 4A, if no ink IK is present on the ink detection sensor S and the ink detection sensor S outputs an OFF signal (Step S1: YES), the control unit 50 notifies the user by displaying on the display unit 70 that the wipe mechanism 10 and ink pan 20 should be deployed to the maintenance position shown in Figure 1 (Step S4). If a configuration is adopted in which the wipe mechanism 10 and ink pan 20 are automatically moved by a drive unit (not shown), the control unit 50 controls the drive unit to deploy the wipe mechanism 10 and ink pan 20 to the maintenance position shown in Figure 1.

[0046] Next, the control unit 50 controls the inkjet head 110 to purge the ink IK from the nozzle 111a (step S5). If a separate control unit for controlling the inkjet head 110 is provided in the printing system 100, the control unit 50 will send a request to this control unit to purge the ink IK.

[0047] Next, the control unit 50 determines whether the time x seconds from when the nozzle 111a purges the ink IK until the ink detection sensor S outputs an ON signal is within a seconds (step S6). This a seconds may be predetermined based on the liquid-repellent film of the inkjet head 110, the material of the ink IK, and experiments. The arrival time x seconds may be the time until at least one ink detection sensor S outputs an ON signal.

[0048] If the arrival time x seconds is within a seconds (step S6: YES), the control unit 50 controls the wiper drive unit 13 to slow down the wiping speed of the wiper blade 11, thereby performing a variable wiping operation that reduces the contact pressure of the wiper blade 11 against the nozzle surface 111 (step S7). The control unit 50 may also slow down the wiping speed as x seconds decreases. For example, if x seconds is less than a1 seconds, the control unit 50 may slow down the wiping speed more than when x seconds is a1 seconds or more but within a seconds. Alternatively, the control unit 50 may slow down the wiping speed in proportion to how short x seconds is.

[0049] If the arrival time x seconds is not within a seconds (step S6: NO), the control unit 50 controls the wiper drive unit 13 to set the wipe speed of the wiper blade 11 to the default setting, causing the wiper blade 11 to perform a normal wipe operation (step S8).

[0050] Furthermore, the control unit 50 determines whether the arrival time x seconds is within b seconds, which is shorter than a seconds (step S9). This b seconds, like a seconds, should preferably be predetermined based on the liquid-repellent film of the inkjet head 110, the material of the ink IK, and experiments.

[0051] If the arrival time x seconds is within b seconds (step S9: YES), the control unit 50 controls the display unit 70 to display a message prompting the replacement of the inkjet head 110 (step S10). The message prompting the replacement of the inkjet head 110 is an example of deterioration information of the inkjet head 110 based on the falling state. The deterioration information does not have to be a message that prompts the replacement of the inkjet head 110, as long as it indicates that the inkjet head 110 has deteriorated. Here, the faster the purged ink IK falls, the more the liquid-repellent film on the nozzle surface 111 is worn, and therefore the more deteriorated the inkjet head 110 is. The control unit 50 can determine the falling state (arrival time x seconds) for each inkjet head 110, so it is good to inform the user of the deterioration information along with information such as the location of the deteriorated inkjet head 110. The notification of deterioration information to the user (step S10) may be simultaneous with the wipe operation (steps S7, S8) or before the wipe operation.

[0052] If the arrival time x seconds is within b seconds (Step S9: YES) and a message is displayed (Step S10), or if the arrival time x seconds exceeds b seconds (Step S9: NO), the control unit 50 determines whether the ink detection sensor S is in the OFF state and outputs an OFF signal (Step S11). This determination is preferably made after the wiping operation by the wiper blade 11 has finished. This is because, in preparation for the next maintenance (detection of the ink IK fall state), it is necessary to confirm that the ink IK adhering to the detection unit Sa has been wiped away by the wiping operation of the nozzle surface 111.

[0053] Furthermore, after the four wiper blades 11 have wiped the nozzle surfaces 111 of all inkjet heads 110 and the detection part Sa of the ink detection sensor S, the inkjet heads 110 can improve the mixing of ink IK by performing a flushing operation in which they drive a piezo element to eject ink IK from the nozzles 111a.

[0054] As shown in Figure 4A, if no ink IK is present on the ink detection sensor S and the ink detection sensor S outputs an OFF signal (step S11: YES), the control unit 50 notifies the user by displaying on the display unit 70 or by other means, or controls a drive unit (not shown) to move the wipe mechanism 10 and the ink pan 20 to a storage position (not shown) (step S12). Then, the process shown in Figure 5 is completed.

[0055] As shown in Figure 4B, if ink IK is attached to the detection unit Sa of the ink detection sensor S and the ink detection sensor S outputs an ON signal (step S11: NO), the control unit 50 stops the operation of the maintenance device 1 (printing system 100) (step S13) and notifies the user of the error through a display on the display unit 70 (step S14). Then, the process shown in Figure 5 is completed.

[0056] In the above description, in order to measure the fall time (arrival time x seconds) of the ink IK purged by the nozzle 111a, all nozzles 111a of all inkjet heads 110 perform ink IK purging. However, for example, only some nozzles 111a of at least one inkjet head 110, or all nozzles 111a of only some of the inkjet heads 110 among multiple inkjet heads 110, may purge the ink IK, and the control unit 50 may obtain the fall time. In this case, it is preferable that all nozzles 111a then purge the ink IK again and perform a wipe operation.

[0057] Furthermore, in the above explanation, the flowchart shown in Figure 5 is performed for each maintenance, but the process shown in Figure 5 may be performed every predetermined number of maintenance cycles or every elapsed time, or it may be performed based on user operations in the input unit 80 shown in Figure 1. In that case, the wipe speed slowed down in step S7 is set as the default for subsequent maintenance cycles, and it is preferable that further adjustments be made to slow down the wipe speed, or that adjustments be made to speed up the wipe speed based on the ink IK drop state after replacing the inkjet head 110, etc.

[0058] Furthermore, although the ink detection sensor S is fixed to the bottom of the inkjet head 110 in the above description, it may also be fixed to the wipe mechanism 10. In that case as well, it is preferable that the ink detection sensor S moves together with the wipe mechanism 10 so that when the wipe mechanism 10 is in the maintenance position shown in Figure 1, the ink detection sensor S is located below the inkjet head 110. Also, the ink detection sensor S is not limited to a reflective photoelectric sensor, but may be other sensors such as a transmissive sensor or a contact sensor.

[0059] Furthermore, the above explanation described an example in which the contact pressure is weakened by slowing down the wipe speed when the arrival time x seconds is within a seconds (step S6 in Figure 5: YES). However, the wipe speed may be adjusted to vary according to the arrival time x seconds, such that the shorter the arrival time x seconds, the slower the wipe speed, and the longer the arrival time x seconds, the faster the wipe speed. In addition, values ​​such as a seconds and b seconds should be determined according to the amount of ink IK to be purged if the amount of ink IK is variable. In addition, values ​​such as a seconds and b seconds may be determined for each inkjet head 110 (ink detection sensor S), or they may be determined for each nozzle 111a (for each height of nozzle 111a) if only some nozzles 111a purge ink IK.

[0060] Furthermore, in the above description, the contact pressure of the wiper blade 11 against the nozzle surface 111 is adjusted by adjusting the wipe speed. However, for example, the control unit 50 may adjust the contact pressure by adjusting the position of the wiper blade 11 in the discharge direction D3. For example, if the wiper blade 11 is brought closer to the nozzle surface 111, the amount of overlap between the wiper blade 11 and the nozzle surface 111 increases, and the contact pressure decreases. Conversely, if the wiper blade 11 is moved away from the nozzle surface 111, the amount of overlap between the wiper blade 11 and the nozzle surface 111 decreases, and the contact pressure increases.

[0061] Furthermore, in the above description, the control unit 50 determines the fall state of the purged ink IK based on the fall time of the purged ink IK. However, the fall state may also be determined by the detection position of the ink IK by the ink detection sensor S, or by the detection area of ​​the ink IK by the ink detection sensor S after a specified time has elapsed since the ink IK was purged. Regarding the detection position, for example, if the nozzle surface 111 is scratched, the purged ink IK may not fall vertically downward, but may fall while shifting in the width direction D2. Therefore, it is advisable to weaken the contact pressure when the distance shifted in the width direction D2 from the specified position where the ink detection sensor S detects the ink IK is long. Regarding the detection area, the more deteriorated the nozzle surface 111 is, the faster the fall speed of the ink IK becomes, and the larger the detection area after a specified time may become. Therefore, it is advisable to weaken the contact pressure when the detection area after a specified time is large.

[0062] Furthermore, in the above description, the nozzle 111a purges the ink IK when the nozzle surfaces 111 intersect horizontally. However, during normal printing, the nozzle surfaces 111 are spread horizontally, meaning the nozzle 111a ejects the ink IK vertically downwards. The orientation of the inkjet head 110 may also be changed during maintenance. Additionally, the wiping direction D1 of the wiper blade 11 is vertically downwards, but it may also be vertically upwards or in the width direction D2, and is not particularly limited.

[0063] Furthermore, while the above description states that the printing system 100 includes an ink circulation unit 130 arranged for each ink IK color, the printing system 100 only needs to include a maintenance device 1 and at least one inkjet head 110, and the configuration shown in Figure 1 is merely an example. Similarly, the maintenance device 1 only needs to include at least one wiper blade 11, at least one ink detection sensor S, and a control unit 50, and the configurations shown in Figures 1 and 2 are merely examples.

[0064] In the embodiment described above, the maintenance device 1 comprises a wiper blade 11, an ink detection sensor S, and a control unit 50. The wiper blade 11 wipes the inkjet head 110 on the nozzle surface 111, which is provided with a nozzle 111a that ejects ink IK. The ink detection sensor S detects the fall state of the ink IK purged by the nozzle 111a when the nozzle surfaces 111 intersect horizontally. The control unit 50 adjusts the contact pressure of the wiper blade 11 against the nozzle surface 111 based on the fall state detected by the ink detection sensor S. The printing system 100 also comprises the maintenance device 1 and the inkjet head 110.

[0065] This means that, for example, if the nozzle surface 111 deteriorates due to wear of the liquid-repellent film on the nozzle surface 111, and the purged ink IK falls quickly along the nozzle surface 111, the deterioration of the nozzle surface 111 can be prevented by reducing the contact pressure. Therefore, according to this embodiment, wear of the nozzle surface 111 of the inkjet head 110 can be suppressed.

[0066] Furthermore, in this embodiment, the maintenance device 1 (printing system 100) further includes a wiper drive unit 13 for moving the wiper blade 11, and the control unit 50 adjusts the contact pressure by controlling the wiper drive unit 13 to adjust the wiping speed of the wiper blade 11.

[0067] This eliminates the need for an adjustment mechanism for the relative position of the wiper blade 11 and the nozzle surface 111 in the discharge direction D3, compared to a method that adjusts the contact pressure by adjusting the overlap amount between the wiper blade 11 and the nozzle surface 111. Therefore, wear of the nozzle surface 111 of the inkjet head 110 can be suppressed with a simple configuration.

[0068] Furthermore, in this embodiment, the maintenance device 1 (printing system 100) further includes a display unit 70, which is an example of a notification unit that notifies the user, and the control unit 50 controls the display unit 70 to notify the user of deterioration information of the inkjet head 110 based on its drop condition (for example, a message prompting the replacement of the inkjet head 110).

[0069] This allows users to take action such as replacing or repairing the inkjet head 110 based on information about the deterioration of the inkjet head 110.

[0070] In this embodiment, the control unit 50 controls the inkjet head 110 to purge ink IK from only some of the nozzles 111a out of the multiple nozzles 111a, and acquires the state of the ink IK that has been purged by some of the nozzles 111a.

[0071] Incidentally, since the ink detection sensor S mentioned above is located below the inkjet head 110, even if all nozzles 111a eject ink IK, the control unit 50 will mainly acquire the state of ink IK falling from the lower nozzles 111a inside the inkjet head 110. In contrast, by purging ink IK only from the upper or central nozzles 111a inside the inkjet head 110, deterioration of the upper or central part of the inkjet head 110 can be determined. Furthermore, by purging ink IK only from nozzles 111a that eject a large amount of ink IK during printing (nozzles 111a that are likely to face the printing area of ​​the material to be printed), deterioration of a desired nozzle surface 111 can be determined. Therefore, wear on the nozzle surface 111 of the inkjet head 110 can be further suppressed.

[0072] It should be noted that the present invention is not limited to the embodiments described above, and the components can be modified and implemented in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the embodiments described above. For example, all the components shown in the embodiments may be combined as appropriate. It goes without saying that various modifications and applications are possible without departing from the spirit of the invention. The invention described in the specification and drawings of this application is listed below.

[0073] <Note 1> A wiper blade that wipes the inkjet head on the nozzle surface where the ink ejection nozzle is provided, An ink detection sensor that detects the state of ink falling after being purged by the nozzle when the nozzle surfaces intersect horizontally, A control unit adjusts the contact pressure of the wiper blade against the nozzle surface based on the drop state detected by the ink detection sensor. A maintenance device characterized by being equipped with the following features.

[0074] <Note 2> The system further includes a wiper drive unit for moving the wiper blade, The control unit adjusts the contact pressure by controlling the wiper drive unit to adjust the wiper speed of the wiper blade. The maintenance device described in Appendix 1, characterized by the features described herein.

[0075] <Note 3> It is further equipped with a notification unit that notifies the user, The control unit controls the notification unit to notify the user of the deterioration information of the inkjet head based on the falling state. A maintenance device as described in Appendix 1 or 2, characterized by the above.

[0076] <Note 4> An inkjet head having a nozzle surface on which nozzles for ejecting ink are provided, A wiper blade for wiping the inkjet head on the nozzle surface, An ink detection sensor that detects the state of ink falling after being purged by the nozzle when the nozzle surfaces intersect horizontally, A control unit adjusts the contact pressure of the wiper blade against the nozzle surface based on the drop state detected by the ink detection sensor. A printing system characterized by comprising the following features.

[0077] <Note 5> The control unit controls the inkjet head to purge ink from only some of the nozzles among the plurality of nozzles, and obtains the state of the ink falling from the some nozzles. The printing system described in Appendix 4, characterized by the features described herein. [Explanation of symbols]

[0078] 1. Maintenance device 10. Wipe mechanism 11 Wiper Blades 12 Wipe Base 13. Wiper drive unit 14 Ball Screw 15,16 Guide rails 17 Base plate 20 Ink Pans 30 Waste liquid tanks 40. Waste liquid hose 50 Control Unit 60 Storage section 70 Display section 80 Input section 90 Interface section 100 Printing Systems 110 Inkjet Heads 111 Nozzle surface 111a Nozzle 120 Head Holder 130 Ink circulation unit 131 Pressurized tank 132 Vacuum Tank 133,134 Ink circulation path 135 Pressure regulating mechanism 136,137 Airflow channels D1 Wipe direction D2 Width direction D3 Discharge direction IK Ink L light detection P Ink Pump S Ink detection sensor Sa detection unit

Claims

1. A wiper blade that wipes the inkjet head on the nozzle surface where the ink ejection nozzle is provided, An ink detection sensor that detects the state of ink falling after being purged by the nozzle when the nozzle surfaces intersect horizontally, A control unit adjusts the contact pressure of the wiper blade against the nozzle surface based on the drop state detected by the ink detection sensor. A maintenance device characterized by being equipped with the following features.

2. The system further includes a wiper drive unit for moving the wiper blade, The control unit adjusts the contact pressure by controlling the wiper drive unit to adjust the wiper speed of the wiper blade. The maintenance device according to claim 1, characterized in that it is a maintenance device.

3. It is further equipped with a notification unit that notifies the user, The control unit controls the notification unit to notify the user of the deterioration information of the inkjet head based on the falling state. The maintenance device according to claim 1, characterized in that it is a maintenance device.

4. An inkjet head having a nozzle surface on which nozzles for ejecting ink are provided, A wiper blade for wiping the inkjet head on the nozzle surface, An ink detection sensor that detects the state of ink falling after being purged by the nozzle when the nozzle surfaces intersect horizontally, A control unit adjusts the contact pressure of the wiper blade against the nozzle surface based on the drop state detected by the ink detection sensor. A printing system characterized by comprising the following features.

5. The control unit controls the inkjet head to purge ink from only some of the nozzles among the plurality of nozzles, and obtains the state of the ink falling from the some nozzles. The printing system according to feature 4.

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