tracing machine

Abstract

The goal is to suppress ink pressure fluctuations even with a simple structure. [Solution] The print head 22 of the drawing machine 2 is equipped with a first port 22c for receiving ink from the ink tank 20a, a second port 22d for discharging ink, a pressure fluctuation adjustment unit 460, and a third port 22e for receiving air supply to the pressure fluctuation adjustment unit 460. The drawing machine 2 is equipped with a solenoid valve 455a that opens and closes an air passage for supplying air to the pressure fluctuation adjustment unit 460 via the third port 22e. When the print head 22 is not discharging ink, the solenoid valve 455a is opened to allow air to be supplied into the pressure fluctuation adjustment unit 460.

Description

Technical Field

[0001] The present disclosure relates to a drawing machine that discharges ink for drawing information on a drawn object.

Background Art

[0002] For example, a drop-on-demand (DOD) type inkjet printing device that discharges ink onto a packaging material such as cardboard for printing is known (see, for example, Patent Document 1). The inkjet printing device of Patent Document 1 is equipped with a print head in which a large number of nozzles are arranged in a direction orthogonal to the conveyance direction of the drawn object.

[0003] Further, Patent Document 2 discloses a print head provided with a reservoir unit for temporarily storing the ink supplied to the nozzles. Inside the reservoir unit of Patent Document 2, a portion for storing the ink and a space open to the atmosphere are provided, and a damper sheet for suppressing pressure fluctuations of the ink is provided between the ink and the atmosphere.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the case of the reservoir unit of Patent Document 2, since a damper sheet must be provided inside, the structure of the reservoir unit becomes complicated.

[0006] The present disclosure has been made in view of such a point, and an object thereof is to enable suppression of pressure fluctuations of ink even with a simple structure. [Means for solving the problem]

[0007] To achieve the above objective, one aspect of this disclosure may be based on a drawing machine that ejects ink for drawing information on an object to be drawn on, which is transported by a transporter. The drawing machine includes an ink tank for containing ink, a recovery tank for recovering ink, a print head for ejecting ink from the first port toward an object to be drawn on while being transported, a first solenoid valve for opening and closing an air passage for supplying air to the pressure fluctuation adjustment unit via the third port, and an air supply control unit for opening the first solenoid valve and supplying air to the pressure fluctuation adjustment unit when the print head is not ejecting ink.

[0008] In this configuration, the pressure fluctuation adjustment unit functions as a damper by bringing the ink received from the first port and the air received from the third port into contact within the pressure fluctuation adjustment unit. By opening the air passage with the first solenoid valve when the print head is not ejecting ink, it is possible to maintain the amount of air inside the pressure fluctuation adjustment unit within an appropriate range. Therefore, it is possible to suppress ink pressure fluctuations with the pressure fluctuation adjustment unit while maintaining a simple structure without providing a damper sheet inside the pressure fluctuation adjustment unit. [Effects of the Invention]

[0009] As explained above, even with a simple structure, it is possible to suppress ink pressure fluctuations. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 shows the overall configuration of an inkjet printing apparatus according to an embodiment of the present invention. [Figure 2] Figure 2 is a block diagram of an inkjet printing device. [Figure 3] Figure 3 is a plan view showing an example of the installation of the drawing machine and inspection machine. [Figure 4] Figure 4 is a front view showing an example of the installation of the drawing machine and inspection machine. [Figure 5] Figure 5 is a perspective view of the drawing machine from the front. [Figure 6] Figure 6 is a perspective view of the drawing machine from above with the top cover removed. [Figure 7] Figure 7 is a perspective view showing the absorbent material with the casing removed. [Figure 8] Figure 8 is a perspective view showing the state with the ink receptacle removed. [Figure 9] Figure 9 shows the relative positions of the print head, ink receptacle, and ink tank, and is a view from above. [Figure 10] Figure 10 is a cross-sectional view of the ink receiving section. [Figure 11] Figure 11 shows the drawing machine body with the print head removed, viewed from the front. [Figure 12] Figure 12 is a perspective view of the print head from the front. [Figure 13] Figure 13 is a perspective view of the print head from the rear. [Figure 14] Figure 14 is a schematic diagram showing the flow path structure of the drawing machine. [Figure 15] Figure 15 is a schematic diagram showing the detailed structure of the print head. [Figure 16] Figure 16 is a diagram equivalent to Figure 15, showing the flow of ink during drawing. [Figure 17] Figure 17 shows the flow of air and ink during a self-refreshing process. [Figure 18] Figure 18 is a flowchart showing an example of the procedure for self-weight refreshing. [Figure 19] Figure 19 shows the flow of air and ink during pump refresh. [Figure 20] Figure 20 is a flowchart showing an example of the pump refresh procedure.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0012] FIG. 1 is a diagram schematically showing the overall configuration during operation of an inkjet printing apparatus 1 including a drawing machine 2 according to an embodiment of the present invention, and FIG. 2 is a block diagram of the inkjet printing apparatus 1. The inkjet printing apparatus 1 includes, for example, a drawing machine 2, an inspection machine 3, a controller 4, and an operation terminal 5.

[0013] The drawing machine 2 is a part that executes drawing processing on an object to be drawn and is configured separately from the controller 4. The inspection machine 3 is a part that determines the quality of the drawing state executed on the object to be drawn by the drawing machine 2 and is configured separately from the controller 4. Since the inkjet printing apparatus 1 according to the present embodiment includes the drawing machine 2 and the inspection machine 3, it is an inkjet printing apparatus that discharges ink for drawing information on an object and determines the quality of the drawing state by imaging.

[0014] The controller 4 is a part that controls the drawing machine 2 and the inspection machine 3 and can also be called a control device, a control unit, etc. The operation terminal 5 is composed of a personal computer or the like and is a part where a user performs, for example, input of drawing information, various settings, selections, confirmations, etc. The operation terminal 5 includes, for example, a terminal-side display unit 5a composed of a liquid crystal display or the like and a terminal-side operation unit 5b composed of a keyboard, a mouse, a pointing device, etc.

[0015] The above configuration example is just one example, and the present invention is not limited to the above configuration example. That is, the controller 4 may be incorporated into the operation terminal 5 or into the drawing machine 2. Alternatively, the operation terminal 5 may function as the controller 4. Figures 1 and 2 show an external device 6 consisting of a programmable logic controller (PLC) or the like, and this external device 6 is connected to the controller 4 in a communicative manner. Control signals output from the external device 6 are input to the controller 4. The external device 6 may be a device that constitutes part of the inkjet printing device 1, or it may be a device separate from the inkjet printing device 1.

[0016] The inkjet printing device 1 is a device for forming a drawing pattern on a workpiece W (an example of an object to be drawn on) that is conveyed horizontally by a conveyor (an example of a conveying device) 10, and is an in-line device used by being incorporated into a manufacturing line (also called a production line). The conveyor 10 is, for example, a belt conveyor, a roller conveyor, etc. The production line is made up of the conveyor 10. The production line is installed in various factories, warehouses, etc. The drawing machine 2 is fixed so that its relative position to the conveyor 10 is in a predetermined positional relationship.

[0017] During operation of the inkjet printing device 1, multiple workpieces W are placed on the transport surface 10a of the transporter 10 and transported sequentially in the direction of arrow A shown in Figure 1. Therefore, the upstream side in the transport direction is the left side of Figure 1, and the downstream side in the transport direction is the right side of Figure 1. The multiple workpieces W are placed on the transport surface 10a with spacing in the direction of arrow A, which is the transport direction. The direction perpendicular to arrow A and along the transport surface 10a is defined as the width direction.

[0018] Workpiece W is not particularly limited, but could include, for example, packaging materials for packing various products. A typical example of packaging material is cardboard. The inkjet printer 1 draws information on the workpiece W being transported by the conveyor 10, such as characters including numbers, symbols, barcodes, two-dimensional codes, images, marks, illustrations, or combinations thereof. When only characters are drawn, the inkjet printer 1 can be called a printing device, and the drawing device 2 can be called a printer. Furthermore, the drawing of information by the inkjet printer 1 also includes printing images, etc. In this case, the inkjet printer 1 can be called a printing device. In the following explanation, the term "drawing" will be used to include both printing and image printing.

[0019] Furthermore, the controller 4 is connected to an encoder 7 for detecting the position of the workpiece W, and a detection sensor 9, which will be described later. Based on the signals output from the encoder 7 and the detection sensor 9, the controller 4 detects the position of the workpiece W. The controller 4 controls the drawing machine 2 so that drawing begins when the workpiece W reaches a predetermined position.

[0020] (Configuration of drawing machine 2) The drawing machine 2 is a DOD (Drop On Demand) type drawing machine that ejects ink only when necessary for drawing operations. However, it may also be a CIJ (Continuous Ink Jet) type drawing machine that ejects ink even when not performing drawing operations. The following description will explain the case in which a DOD type drawing machine is used as drawing machine 2 in this embodiment.

[0021] As shown in Figure 2, the drawing machine 2 includes an ink supply unit 20, a print head drive unit 21, and a DOD print head (hereinafter referred to as the print head) 22. The drawing machine 2 also includes a drawing machine body 25 (shown in Figure 1) on which the print head 22 is installed. The drawing machine body 25 is fixed to a transporter 10 or the like.

[0022] The print head 22 is fixed inside the drawing machine body 25, and the positional relationship between the drawing machine body 25 and the print head 22 is fixed. The ink supply unit 20 and the print head drive unit 21 are also housed inside the drawing machine body 25.

[0023] The print head 22 of the DOD-type drawing machine 2 is, for example, a component corresponding to the ejection unit, and ejects ink supplied from a removable cartridge 300 toward the workpiece W being transported by the transporter 10. The nozzle group 22a provided on the front end surface of the print head 22 is arranged in the direction of gravity, i.e., vertically. A drawing pattern is formed on the workpiece W by the ink ejected from the nozzle group 22a of the print head 22. There are several types of print head structures, but it may be any of the following, for example, a thermal inkjet type, a valve jet type, or a piezo type. In this embodiment, a piezo type print head is used as the print head 22 because it is capable of drawing from low resolution to high resolution, has a wide drawing width, and has high durability. The ink ejected from the print head 22 flies out of the drawing machine body 25 and adheres to the workpiece W.

[0024] The ink supply unit 20 is the part that supplies ink to the print head 22, and includes an ink tank 20a that houses the ink to be supplied to the print head 22, and a cartridge 300 for replenishing the ink in the ink tank 20a.

[0025] The print head drive unit 21 is controlled by the control unit 40, which will be described later, when performing drawing operations. The print head drive unit 21 generates a drive electrical waveform for driving the print head 22 and outputs it to the print head 22. The drive electrical waveform is a waveform for individually driving the drive elements (piezo oscillators) provided at each ejection port of the print head 22 at timings based on the drawing command output from the control unit 40.

[0026] (Configuration of the inspection machine) Inspection machine 3 is a device that determines the quality of the drawing state of the drawing pattern drawn on the workpiece W based on the drawing data, using an image acquired by imaging the workpiece W, and corresponds to an image inspection unit. Inspection machine 3 can also be called an image inspection device. Inspection machine 3 is installed downstream of drawing machine 2, and is capable of inspecting the drawing state of the workpiece W drawn by drawing machine 2.

[0027] The inspection machine 3 comprises an illumination unit 30, an imaging unit 31, a control unit 32, and a storage unit 33. The illumination unit 30 is composed of, for example, light-emitting diodes, and is controlled by the control unit 32 to emit light at predetermined timings to illuminate the drawn portion of the workpiece W. The imaging unit 31 is a component for capturing images of the drawing pattern formed on the workpiece W and generating an image. This imaging unit 31 includes an optical system 31a that includes a lens that receives light irradiated from the illumination unit 30 and reflected from the surface of the workpiece W, an image sensor 31b that receives light emitted from the optical system 31a, and an AF motor 31c. The AF motor 31c is a component for automatically focusing on the drawn portion of the workpiece W by driving the focusing lens of the optical system 31a. The autofocus method is not particularly limited, and examples include a contrast method.

[0028] The image sensor 31b is composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) sensor. The image sensor 31b captures an image of the workpiece W to be drawn and generates an image. For example, the light intensity signal of the light-receiving element of the image sensor 31b is output to an FPGA (Field Programmable Gate Array) for processing (not shown in the diagram) and also output to a DSP (Digital Signal Processor) for processing.

[0029] The control unit 32 has an imaging setting unit 32a. The imaging setting unit 32a sets imaging setting parameters and reflects the set imaging setting parameters when imaging the workpiece W. The imaging setting parameters include multiple parameters such as the timing of illumination by the illumination unit 30, brightness (amount of light emitted), exposure time by the imaging unit 31, and focus (focal position) of the imaging unit 31. Although not shown, the GUI for setting imaging setting parameters has areas where the brightness of illumination, exposure time, focus, etc., can be set individually. When the user inputs each parameter on the GUI, the imaging setting unit 32a accepts the setting operation by the user and outputs each parameter to, for example, the storage unit 33 for storage. Each parameter can be read from the storage unit 33 as needed.

[0030] When acquiring image data of the workpiece W, the imaging setting unit 32a outputs imaging setting parameters to the illumination unit 30 and the imaging unit 31. The illumination unit 30 and the imaging unit 31 operate according to the imaging setting parameters. When the illumination unit 30 receives the imaging setting parameters, it sets them within the imaging unit 31 so that the received imaging setting parameters are reflected during imaging. Similarly, when the imaging unit 31 receives the imaging setting parameters, it sets them within the imaging unit 31 so that the received imaging setting parameters are reflected during imaging. When the illumination unit 30 and the imaging unit 31 receive an imaging trigger, they illuminate the workpiece W according to the imaging setting parameters and take images to acquire image data of the workpiece W.

[0031] The control unit 32, for example, causes the imaging unit 31 to image the workpiece W, acquires image data of the workpiece W, and performs an inspection on the acquired image of the workpiece W based on a pre-configured inspection tool. The pass / fail determination unit 32b, located in the control unit 32 of the inspection machine 3, creates an inspection result using the inspection tool and compares it with the inspection conditions. The inspection conditions are obtained from the drawing data generation unit 40b of the controller 4.

[0032] (Integrated fittings) As shown in Figure 1, the inkjet printer 1 is equipped with an integrated fitting 90 for fixing the inspection machine 3 to the drawing machine body 25 which houses the print head 22. The integrated fitting 90 has a part to which the drawing machine body 25 is attached and a part to which the inspection machine 3 is attached. The integrated fitting 90 has a predetermined dimension in the direction of transport of the workpiece W, and when the inspection machine 3 is fixed to the drawing machine body 25 by the integrated fitting 90, the inspection machine 3 and the print head 22 can be positioned at a distance from each other in the direction of transport of the workpiece W, that is, in a fixed position relationship. By fixing the inspection machine 3 to the drawing machine body 25 with the integrated fitting 90, the relative fixed position relationship with the print head 22 is defined.

[0033] Figure 3 is a plan view showing an example of the installation of the drawing machine 2 and the inspection machine 3. When the workpiece W is being transported in the direction of arrow A, the inspection machine 3 can be installed downstream of the drawing machine 2 in the direction of workpiece W transport by providing the integrated fitting 90 as shown by the solid line. On the other hand, when the workpiece W is being transported in the direction of arrow B, opposite to the direction of arrow A, the inspection machine 3 can be installed downstream of the drawing machine 2 in the direction of workpiece W transport by providing the integrated fitting 90 as shown by the dashed line. In addition, by providing both the integrated fitting shown by the solid line and the integrated fitting 90 shown by the dashed line, it is possible to accommodate both the transport directions of arrow A and arrow B.

[0034] Figure 4 shows an example of the installation of the drawing machine 2 and the inspection machine 3, and is a view from the side from which the ink is ejected (front view). As shown in Figure 4, the inspection machine 3 is fixed to the drawing machine body 25 by an integrated fitting 90 such that the vertical center of the drawing area and the vertical center of the field of view of the imaging unit 31 of the inspection machine 3 are at the same height.

[0035] (Detection sensor) As shown in Figure 1, the inkjet printing apparatus 1 is equipped with a detection sensor 9 that detects the arrival of a workpiece W being transported by a transporter 10. The detection sensor 9 is installed upstream of the drawing machine 2 in the transport direction of the workpiece W. The detection sensor 9 is equipped with, for example, an optical motion measuring sensor or a distance sensor (not shown), and these sensors enable the detection of the arrival of the transported workpiece W. When the detection sensor 9 detects the arrival of the workpiece W, it transmits a detection signal to the controller 4. Based on the detection signal output from the detection sensor 9, the controller 4 determines that the workpiece W has arrived at a predetermined position and, after a predetermined drawing delay time has elapsed, causes the drawing machine 2 to start drawing.

[0036] (Controller 4 configuration) As shown in Figure 2, the controller 4 comprises a control unit 40, a storage unit 41, and an operation display unit 42. The control unit 40 is composed of a microcomputer including, for example, a central processing unit and various memories, and is capable of executing pre-stored software. The control unit 40 is provided with a drawing setting unit 40a, a drawing data generation unit 40b, an inspection setting unit 40c, a display screen generation unit 40d, and a mode switching unit 40e. The drawing setting unit 40a, drawing data generation unit 40b, inspection setting unit 40c, display screen generation unit 40d, and mode switching unit 40e of the control unit 40 are parts composed of hardware and software, and for convenience they are described separately as the drawing setting unit 40a, drawing data generation unit 40b, inspection setting unit 40c, display screen generation unit 40d, and mode switching unit 40e, but they may be integrated in hardware.

[0037] The operation display unit 42 includes a controller-side display unit 42a, which is, for example, a liquid crystal display, and a controller-side operation unit 42b, which is, for example, an operation key. The controller-side operation unit 42b is the part that accepts various operations such as drawing content and settings. Various screens generated by the display screen generation unit 40d are displayed on the controller-side display unit 42a, so that the user can operate the controller-side operation unit 42b while looking at the controller-side display unit 42a. The operation status of the controller-side operation unit 42b can be acquired by the control unit 40.

[0038] The controller-side operation unit 42b may be a touch panel. The touch panel is a component capable of detecting operations performed by the user's finger. The type of touch panel is not particularly limited and examples include capacitive touch panels and infrared touch panels. User operation information on the touch panel is transmitted to the control unit 40.

[0039] The drawing setting unit 40a is the part that sets the drawing content to be drawn on the workpiece W to be drawn on. The drawing data generation unit 40b is the part that defines the ejection of ink from the print head 22 and generates drawing data corresponding to the drawing content set in the drawing setting unit 40a. The control unit 40 outputs a control signal to the print head drive unit 21 based on the drawing data generated by the drawing data generation unit 40b, and controls the ejection of ink from the ejection port of the print head 22.

[0040] The inspection setting unit 40c is the part that performs inspection settings by the inspection machine 3. The storage unit 41 is the part that stores the relative fixed position relationship between the inspection machine 3 and the print head 22. Based on the drawing content set by the drawing setting unit 40a and the relative fixed position relationship stored in the storage unit 41, the inspection setting unit 40c assists the user in setting inspection settings.

[0041] (Detailed structure of the drawing machine) Figures 1 to 4 show the approximate shapes of the drawing machine 2, print head 22, drawing machine body 25, cartridge 300, etc. However, the specific shapes of the drawing machine 2, print head 22, drawing machine body 25, cartridge 300, etc. are shown in Figures 5 and onward. The shapes shown in Figures 5 and onward may differ slightly from those shown in Figures 1 to 4, because Figures 1 to 4 are conceptual diagrams.

[0042] As shown in Figure 5, the drawing machine body 25 is equipped with a box-shaped housing 200 that extends in the longitudinal direction. The ink tank 20a shown in Figure 2 is located inside the housing 200 and is not visible from the outside. In the installed state of the drawing machine 2, the longitudinal direction of the housing 200 coincides with the width direction of the conveyor 10. In this specification, the longitudinal direction of the housing 200 is defined as the front-to-back direction, and the side facing the workpiece W during installation is defined as the front. Also, the side located to the right when viewing the drawing machine 2 from the front is defined as the right side, the side located to the left when viewing the drawing machine 2 from the front is defined as the left side, and the left-to-right direction of the drawing machine 2 is defined as the width direction. This definition of direction is for the convenience of explanation and does not limit the directions according to the present invention.

[0043] As shown in Figure 5, the housing 200 has a shape that is close to a rectangular parallelepiped, with a long front-to-back orientation. Therefore, the front-to-back dimension of the housing 200 is longer than the left-to-right dimension and the up-to-down dimension of the housing 200.

[0044] Because the housing 200 has a shape close to a rectangular parallelepiped, the outer surface of the housing 200 includes six surfaces. Specifically, the outer surface of the housing 200 includes a front surface 201 positioned facing the workpiece W, a rear surface 202 located opposite the front surface 201, a right side surface 203 located to the right when viewed from the direction facing the front surface 201, a left side surface 204 located to the left when viewed from the direction facing the front surface 201, a top surface 205, and a bottom surface 206. The front surface 201, rear surface 202, right side surface 203, and left side surface 204 are surfaces that constitute the outer surface of the housing 200. One end surface in the longitudinal direction of the outer surface of the housing 200 is the front surface 201, and the other end surface in the longitudinal direction of the outer surface of the housing 200 is the rear surface 202. A print head 22 for ejecting ink toward the workpiece W being transported is provided on the front surface 201. The front surface 201 may also be called the front, or the rear surface 202 may be called the back.

[0045] As shown in Figure 5, the drawing machine 2 is equipped with a removable upper cover 230 attached to the drawing machine body 25. Figure 6 shows the state with the upper cover 230 removed. The drawing machine 2 is equipped with an absorbent 240 (shown only in Figure 6) for absorbing ink leaked from the print head 22, and a casing 241 that houses the absorbent 240. The absorbent 240 is made of sponge, fiber, or the like.

[0046] The casing 241 has a vertically elongated shape and is detachably mounted on the front 201 of the housing 200 to the left of the print head 22. Figure 7 shows the casing 241 removed from the drawing machine body 25 and moved forward. As shown in Figure 7, the casing 241 can be removed and replaced from the drawing machine body 25 without removing the upper cover 230.

[0047] The absorber 240 is provided on only one side of the drawing machine body 25, either the left or the right. In this example, the casing 241 housing the absorber 240 is provided on the left side of the drawing machine body 25, so the absorber 240 is not provided on the right side of the drawing machine body 25. For this reason, a box-shaped member 242 that does not house the absorber 240 is detachably provided on the right side of the drawing machine body 25. The shape of the box-shaped member 242 is symmetrical to that of the casing 241. If the absorber 240 is to be provided on the left side of the drawing machine body 25, the casing 241 housing the absorber 240 should be detachably provided on the left side of the drawing machine body 25, and the box-shaped member 242 should be detachably provided on the right side.

[0048] Below the print head 22 in the drawing machine body 25, there is an ink receiving section 245 having a liquid delivery structure for guiding ink leaked from the print head 22 to an absorber 240. The ink receiving section 245 is detachably provided at the bottom of the front surface 201 of the drawing machine body 25. Figure 8 shows the state in which the casing 241 and box-shaped member 242 and the ink receiving section 245 have been removed from the drawing machine body 25, and the ink receiving section 245 has been moved forward.

[0049] As shown in Figure 9, the ink receiving section 245 is formed to extend to the left and right below the print head 22, and as a whole, it has a concave shape that opens upward. Above the left side of the ink receiving section 245 is a casing 241 that houses the absorber 240, while above the right side of the ink receiving section 245 is a box-shaped member 242. As shown in Figure 10, the bottom surface 245a of the ink receiving section 245 slopes downward from the center in the left-right direction toward the left. This allows ink leaking from the print head 22 to be received by the bottom surface 245a of the ink receiving section 245 and then flow to the left side, i.e., the side where the absorber 240 is located, so that the ink can be reliably absorbed by the absorber 240. If the absorber 240 is located on the right side, an ink receiving section 245 with a bottom surface 245a that slopes in the opposite direction can be installed.

[0050] Figure 9 shows the positional relationship between the ink tank 20a and the print head 22. The ink tank 20a is installed at the bottom of the drawing machine body 25. As shown in Figure 9, in a plan view, the ink tank 20a is positioned behind the print head 22, and to the left and right of the print head 22, but not in front of the print head 22. In other words, in this embodiment, the ink tank 20a is provided so as to surround the portion of the print head 22 other than the side with the nozzle group 22a in a plan view.

[0051] As shown in Figure 6, the drawing machine 2 is equipped with an operation button 250. The operation button 250 is a component that receives user instructions for controlling the drawing machine 2. There may be one operation button 250 or two or more. The operation button 250 is located on the upper part of the rear surface 202 of the housing 200, on the opposite side from the print head 22. This allows the user to operate the operation button 250 from the opposite side of the transport machine 10, resulting in good operability. Examples of operation buttons 250 include a test button operated when performing a test drawing, and a cleaning button operated when cleaning the drawing machine 2, but they may be buttons that perform any function.

[0052] The drawing machine 2 is equipped with a waste liquid bottle 251. The waste liquid bottle 251 is used as a recovery tank for collecting ink and is located on the rear surface 202 of the housing 200, on the opposite side from the print head 22. The waste liquid bottle 251 is a container for storing ink that has been supplied from the ink tank 20a to the print head 22 but has not been discharged toward the workpiece W. The ink inlet (not shown), which is the opening of the waste liquid bottle 251, is located at the top of the waste liquid bottle 251 and is formed at a position higher than the liquid level of the ink contained in the ink tank 20a (shown in Figure 9). The ink supplied to the print head 22 that has not been discharged toward the workpiece W is supplied to the opening of the waste liquid bottle 251 by the supply unit and then flows into the interior of the waste liquid bottle 251 from the opening. The waste liquid bottle 251 is configured to be detachable from the drawing machine body 25, so that the ink inside the waste liquid bottle 251 can be discharged as needed.

[0053] Furthermore, as shown in Figure 6 with the top cover 230 removed, the upper side of the drawing machine body 25 is equipped with an air filter 260 for filtering the air drawn into the drawing machine body 25, a spirit level 261, and a hand valve 262 for manually opening and closing the internal piping. The air filter 260, spirit level 261, and hand valve 262 are arranged in a front-to-back direction. When the top cover 230 is attached to the drawing machine body 25, the air filter 260, spirit level 261, and hand valve 262 are covered by the top cover 230 and become invisible from the outside.

[0054] The drawing machine body 25 detachably holds the print head 22. Figure 11 is a front perspective view of the drawing machine body 25 with the print head 22, the casing 241 housing the absorber 240, the box-shaped member 242, and the ink receiving section 245 removed. As shown in Figure 11, a head housing section 400 is formed in the middle of the drawing machine body 25 in the left-right direction, where the installed print head 22 is housed. The front end of the head housing section 400 has a mounting opening 400a for inserting and attaching the print head 22. This mounting opening 400a is located on the front surface of the drawing machine body 25, between the part where the casing 241 housing the absorber 240 is attached and the part where the box-shaped member 242 is attached. The print head 22 may be housed in the head housing 400, with the entire print head 22 contained within the head housing 400, or the front portion of the print head 22 may be exposed to the outside of the head housing 400 through the mounting opening 400a.

[0055] The vertical dimension of the head housing 400 is set to be longer than the horizontal dimension; therefore, the head housing 400 has a vertically elongated shape. To correspond to this shape of the head housing 400, the mounting opening 400a also has a vertically elongated shape.

[0056] Figures 12 and 13 show the print head 22. The print head 22 is box-shaped and housed in the head housing 400. The relationship between the vertical dimension and the horizontal dimension of the print head 22 is similar to the relationship between the vertical dimension and the horizontal dimension of the head housing 400, with the vertical dimension being set to be relatively longer.

[0057] The print head 22 is inserted into the mounting opening 400a from its rear end. On the front side of the print head 22, opposite to the insertion direction, a flange portion 22A is formed to protrude upward, downward, to the right, and to the left. The flange portion 22A of the print head 22 is located outside the mounting opening 400a. Since the nozzle group 22a is provided on the front end surface of the print head 22, the nozzle group 22a is located outside the mounting opening 400a of the drawing machine body 25 when the print head 22 is attached to the drawing machine body 25.

[0058] The print head 22 includes a first port 22c, a second port 22d, and a third port 22e. The first port 22c, the second port 22d, and the third port 22e protrude to the rear from the rear end surface 22b of the print head 22, that is, from the side opposite to the side where the nozzle group 22a is provided. The first port 22c is located at the bottom, the third port 22e is located at the top, and the second port 22d is located between the first port 22c and the third port 22e. In other words, the first port 22c, the second port 22d, and the third port 22e are arranged in a single row with spacing between them in the vertical direction of the print head 22.

[0059] The rear end surface 22b of the print head 22 is provided with a head-side electrical connection part 22f, which is connected to the main unit-side electrical connection part (described later) of the drawing machine body 25. The head-side electrical connection part 22f is composed of, for example, conductive electrical terminals or connectors, and protrudes toward the rear, similar to the first port 22c, the second port 22d, and the third port 22e.

[0060] The head-side electrical connection section 22f is located to the side of the first port 22c, the second port 22d, and the third port 22e. Specifically, the first port 22c, the second port 22d, and the third port 22e are arranged vertically on the left side of the rear end surface 22b of the print head 22, while the head-side electrical connection section 22f is located on the right side of the rear end surface 22b of the print head 22. By arranging the head-side electrical connection section 22f and the first port 22c, the second port 22d, and the third port 22e separately on the left and right sides, even if ink leaks from the first port 22c, etc., it becomes less likely to adhere to the head-side electrical connection section 22f. Alternatively, the first port 22c, the second port 22d, and the third port 22e may be arranged on the right side of the rear end surface 22b of the print head 22, and the head-side electrical connection section 22f may be arranged on the left side of the rear end surface 22b of the print head 22.

[0061] Furthermore, although not shown in the diagram, the print head electrical connection section 22f may be positioned above the first port 22c, the second port 22d, and the third port 22e. This makes it less likely for ink to adhere to the print head electrical connection section 22f even if it leaks from the first port 22c, etc.

[0062] A wall portion 22h is provided on the rear end surface 22b of the print head 22 between the head-side electrical connection portion 22f and the first port 22c, second port 22d, and third port 22e. The wall portion 22h is a portion that separates the area on the rear end surface 22b of the print head 22 where the head-side electrical connection portion 22f is located from the area where the first port 22c, second port 22d, and third port 22e are located. As a result, even if ink leaks from the first port 22c, etc., the wall portion 22h prevents the ink from flowing toward the head-side electrical connection portion 22f. Note that the wall portion 22h may be provided only if necessary.

[0063] As shown in Figure 11, the rear side surface 401 located at the back of the head housing 400 is provided with a lower port 401c, an intermediate port 401d, and an upper port 401e, which are connected to the first port 22c, the second port 22d, and the third port 22e, respectively. In this embodiment, since the first port 22c, the second port 22d, and the third port 22e are located on the left side, the lower port 401c, the intermediate port 401d, and the upper port 401e are also located on the left side of the rear side surface 401. The first port 22c, the second port 22d, and the third port 22e are connected to the lower port 401c, the intermediate port 401d, and the upper port 401e by inserting one into the other.

[0064] An electrical connection part 401f for the main body is provided on the rear side surface 401 of the head housing section 400. In this embodiment, since the head-side electrical connection part 22f is provided on the right side, the electrical connection part 401f for the main body is also provided on the right side of the rear side surface 401. The electrical connection part 401f for the main body is composed of, for example, conductive electrical terminals or connectors, similar to the electrical connection part 22f for the head. For example, one of the electrical connection part 401f for the main body and the electrical connection part 22f for the head may be composed of a male connector and the other of a female connector.

[0065] (Ink and air flow path structure) Figure 14 is a schematic diagram showing the flow path structure of the drawing machine 2. The drawing machine 2 is equipped with a cartridge flow path 450, which is composed of piping members connecting a cartridge 300 and an ink tank 20a. The ink contained in the cartridge 300 is supplied to the ink tank 20a via the cartridge flow path 450. The cartridge flow path 450 is equipped with, in order from upstream to downstream, an ink filter 450a for filtering the ink, an ink pump 450b for supplying the ink, and a cartridge valve 450c for opening and closing the cartridge flow path 450. The cartridge valve 450c is a solenoid valve. The ink pump 450b and the cartridge valve 450c are controlled by, for example, a controller 4.

[0066] The ink tank 20a is equipped with a level meter 451 for measuring the amount of ink in the ink tank 20a. The measurement result from the level meter 451 is output to the controller 4. The controller 4 controls the ink pump 450b and the cartridge valve 450c to supply ink from the cartridge 300 to the ink tank 20a so that the amount of ink in the ink tank 20a is within a predetermined range.

[0067] The drawing machine 2 is equipped with a supply path 452 consisting of piping members extending from the ink tank 20a to the lower port 401c. The supply path 452 is for supplying ink contained in the ink tank 20a to the print head 22. A supply valve 452a, consisting of a solenoid valve that opens and closes the supply path 452, is provided in the middle of the supply path 452. The supply valve 452a is controlled by the controller 4 and the air supply control unit 27. The lower port 401c is connected to the downstream side of the supply path 452. Since this lower port 401c is connected to the first port 22c of the print head 22, the first port 22c is a port that receives ink from the ink tank 20a. The print head 22 discharges the ink from the first port 22c toward the workpiece W being transported.

[0068] The drawing machine 2 is equipped with a discharge channel 453 consisting of a piping member extending from the intermediate port 401d to the waste liquid bottle 251. The discharge channel 453 is a channel that discharges the ink in the pressure fluctuation adjustment unit 460 (described later) to the waste liquid bottle 251 via the second port 22d and the intermediate port 401d. The inner diameter of the discharge channel 453 is set to be larger than a certain size so that the ink does not accumulate due to surface tension.

[0069] Furthermore, the discharge channel 453 is designed to suppress undulations that oppose gravity. Specifically, the upstream side of the discharge channel 453 is connected to the intermediate port 401d, and the downstream side of the discharge channel 453 is connected to the waste liquid bottle 251. The shape of the discharge channel 453 is set such that the upstream side of the discharge channel 453 is located above the downstream side and the middle section in the flow direction, and the downstream side of the discharge channel 453 is located below the upstream side and the middle section in the flow direction. This shape allows the ink to flow naturally from the upstream side to the downstream side of the discharge channel 453 by gravity. In other words, the discharge channel 453 is designed to allow the ink to flow naturally.

[0070] A discharge valve 453a, consisting of a solenoid valve that opens and closes the discharge channel 453, is provided in the middle of the discharge channel 453. The discharge valve 453a is controlled by the controller 4 and the air supply control unit 27. The intermediate port 401d is connected to the second port 22d of the print head 22, so the second port 22d is a port that discharges ink that was not ejected from the print head 22 to the waste liquid bottle 251.

[0071] The drawing machine 2 includes a first flow path 454 connected to the upper part (where air is present) of the ink tank 20a, and a second flow path 455 connected to the third port 22e. The first flow path 454 extends from the upper part of the ink tank 20a to the air filter 260 and can be vented to the atmosphere via the air filter 260. A tank-side solenoid valve 454a for opening and closing the first flow path 454 is provided on the ink tank 20a side of the first flow path 454. A filter-side solenoid valve 454b for opening and closing the first flow path 454 is provided on the air filter 260 side of the first flow path 454. The tank-side solenoid valve 454a and the filter-side solenoid valve 454b are controlled by the controller 4 and the air supply control unit 27.

[0072] A pressure gauge 454c is provided between the tank-side solenoid valve 454a and the filter-side solenoid valve 454b of the first flow path 454 to measure the pressure in the first flow path 454. The measurement results from the pressure gauge 454c are output to the controller 4 and the air supply control unit 27.

[0073] The second flow path 455 extends from the third port 22e to the air filter 260 and can be vented to the atmosphere via the air filter 260. An air flow path shut-off valve 455a, which is a solenoid valve that opens and closes the second flow path 455, is provided on the third port 22e side of the second flow path 455. The second flow path 455 is a flow path through which air flows, but since it is connected to the pressure fluctuation adjustment unit 460 via the upper port 401e and the third port 22e, there is a risk that ink in the damper chamber 460a (shown in Figure 15, etc.) of the pressure fluctuation adjustment unit 460 may flow into the second flow path 455. In this embodiment, the portion of the second flow path 455 on the third port 22e side of the air flow path shut-off valve 455a is inclined downwards as it approaches the third port 22e. As a result, even if ink in the damper chamber 460a flows into the second flow path 455, the incoming ink can be returned to the damper chamber 460a by its own weight.

[0074] An air pump 455b is provided on the air filter 260 side of the second flow path 455 to supply air to the third port 22e. The air pump 455b is for pressurizing and supplying air to the pressure fluctuation adjustment unit 460 via the third port 22e. The air flow path valve 455a and the air pump 455b are controlled by the controller 4 and the air supply control unit 27. Furthermore, the portion of the second flow path 455 between the air flow path valve 455a and the air pump 455b is connected to the tank-side solenoid valve 454a and the filter-side solenoid valve 454b of the first flow path 454.

[0075] Furthermore, the air pump 455b can also pump air into the ink tank 20a via the first passage 454. That is, by closing the filter-side solenoid valve 454b and the air passage on / off valve 455a, and opening the tank-side solenoid valve 454a, the air pump 455b can be rotated to pump air into the ink tank 20a and pressurize the ink tank 20a. In this way, pumping air to the pressure fluctuation adjustment unit 460 and pressurizing the ink tank 20a can be performed with a single air pump 455b. Although not shown, separate air pumps may be provided for pumping air to the pressure fluctuation adjustment unit 460 and for pressurizing the ink tank 20a.

[0076] As shown in Figure 15, the print head 22 includes an ink storage chamber R where ink is stored before being ejected from the nozzle group 22a, and a pressure fluctuation adjustment unit 460 that suppresses pressure fluctuations of the ink in the ink storage chamber R. A first port 22c is connected to the lower side of the ink storage chamber R, and ink is supplied to the ink storage chamber R via the first port 22c.

[0077] The upper side of the ink storage chamber R is the outlet side through which ink that was not ejected from the nozzle group 22a flows out. A pressure fluctuation adjustment unit 460 is connected to the outlet side of this ink storage chamber R via piping 26. The ink storage chamber R constitutes part of the ink flow path between the first port 22c and the second port 22d. The pressure fluctuation adjustment unit 460 is positioned in the middle of the ink flow path between the first port 22c and the second port 22d. More specifically, the pressure fluctuation adjustment unit 460 is interposed between the ink storage chamber R and the second port 22d. The pressure fluctuation adjustment unit 460 may also be connected to the ink inflow side, which is the lower side of the ink storage chamber R. However, connecting the pressure fluctuation adjustment unit 460 to the ink outlet side of the ink storage chamber R is advantageous because it can suppress the mixing of air into the ink storage chamber R.

[0078] The pressure fluctuation adjustment unit 460 is a so-called air damper, and a damper chamber 460a is formed inside it. Ink from the ink tank 20a flows into the ink storage chamber R via the supply valve 452a and the first port 22c, and the ink that is not discharged from the nozzle group 22a flows into the damper chamber 460a and is stored there. The second port 22d is connected to the lower part of the damper chamber 460a and is a port for discharging the ink stored in the damper chamber 460a. Therefore, the discharge valve 453a is positioned in the middle of the discharge passage 453 that discharges the ink in the pressure fluctuation adjustment unit 640 to the waste liquid bottle 251 via the second port 22d, and is a second solenoid valve that opens and closes the discharge passage 453.

[0079] The third port 22e is located above the second port 22d and is connected to the upper portion of the damper chamber 460a. The third port 22e is a port for receiving the air supply from the pressure fluctuation adjustment unit 460 to the damper chamber 460a. Therefore, the air passage on / off valve 455a is a first solenoid valve positioned in the middle of the air passage for supplying air to the pressure fluctuation adjustment unit 460 via the third port 22e.

[0080] As shown in Figure 16, during operation of the drawing machine 2, ink flowing in from the ink tank 20a and air are contained in the damper chamber 460a of the pressure fluctuation adjustment unit 460. The damper chamber 460a does not have a damper sheet, and the liquid surface of the ink contained in the damper chamber 460a is in contact with the air. In other words, the pressure fluctuation adjustment unit 460 is an air damper without a damper sheet.

[0081] As shown by multiple arrows in Figure 16, during drawing, ink from the ink tank 20a flows into the ink storage chamber R via the supply valve 452a and the first port 22c, and is discharged from the nozzle group 22a. Ink that is not discharged from the nozzle group 22a flows into the damper chamber 460a of the pressure fluctuation adjustment unit 460 and is stored there. Since air is also present in the damper chamber 460a, for example, when the print head 22 vibrates, the air in the damper chamber 460a expands and contracts, suppressing pressure fluctuations of the ink in the ink storage chamber R. As a result, fluctuations in the discharge pressure of the ink from the nozzle group 22a can be absorbed, improving drawing accuracy. In other words, fluctuations in the pressure applied to the meniscus formed on the nozzle group 22a can be suppressed, preventing non-discharge due to nozzle failure, and consequently improving drawing accuracy. In particular, since the pressure fluctuation adjustment unit 460 does not have a damper sheet, the response speed to pressure fluctuations of the ink in the ink storage chamber R is extremely fast, which further improves drawing accuracy.

[0082] Since the pressure fluctuation adjustment unit 460 does not have a damper sheet, the ink level in the ink storage chamber R may rise, for example, while drawing is in progress. Factors that cause the ink level in the ink storage chamber R to rise include the air in the damper chamber 460a coming into direct contact with the ink surface, causing the air to dissolve into the ink, or air mixing into the ink as bubbles due to vibration or shock, and the air being discharged from the damper chamber 460a through the second port 22d. When the ink level in the ink storage chamber R rises, the amount of air in the ink storage chamber R decreases accordingly, which may reduce the pressure fluctuation suppression effect. To address this, the drawing machine 2 according to this embodiment includes an air supply control unit 27 (shown in Figure 2) that performs refresh control by opening the air flow path on / off valve 455a and the discharge valve 453a when the print head 22 is not ejecting ink (when not drawing), and a timing storage unit 28 that stores the timing of the refresh control. The timing memory unit 28 automatically stores the date and time of the last refresh control. The timing memory unit 28 also stores information regarding the frequency of refresh control. For example, if it is desired to perform refresh control again after a certain period of time has elapsed since the last refresh control, the "certain period of time" is stored in the timing memory unit 28 and used in the flow described later.

[0083] The air supply control unit 27 and the timing storage unit 28 may be provided in the drawing machine body 25, or they may be separate from the drawing machine body 25 and provided outside of the drawing machine body 25. For example, the air supply control unit 27 and the timing storage unit 28 can be built into the controller 4, in which case the air supply control unit 27 and the timing storage unit 28 of the controller 4 will cause the drawing machine body 25 to perform refresh control.

[0084] The example shown in Figure 17 illustrates a gravity-based refresh method that uses the weight of the ink to supply air into the ink storage chamber R. Gravity-based refresh is possible because the discharge channel 453 is designed to suppress undulations that oppose gravity and has an inner diameter greater than a certain amount to prevent ink from accumulating due to surface tension. In the case of refresh using the air pump 455b described later, the discharge channel 453 may have undulations that oppose gravity and may have an inner diameter less than a certain amount.

[0085] The details of the self-weight refresh will be explained based on the flowchart shown in Figure 18. In step SA1, the user inputs a maintenance start signal. In step SA2, when the air supply control unit 27 detects that a maintenance start signal has been given, it switches the drawing machine 2, which is currently drawing, into maintenance mode. Maintenance mode is when ink is not ejected from the print head 22, that is, when the print head 22 is not ejecting ink.

[0086] In step SA3, the air supply control unit 27 obtains the previous refresh date and time stored in the timing memory unit 28 and the current date and time. Based on the obtained previous refresh date and time and the current date, the air supply control unit 27 determines whether a certain amount of time (period) has elapsed since the previous refresh date and time. If a certain amount of time has not elapsed since the previous refresh date and time, the process proceeds to step SA7, and the drawing machine 2 performs normal maintenance operations without performing refresh control. Note that the previous refresh date and time may be affected by other maintenance. Specifically, if the print head 22 malfunctions or if the ink stored in the ink storage chamber 460 is replaced, the air supply control unit 27 will perform refresh control regardless of the previous refresh date and time, and the previous refresh date and time stored in the timing memory unit 28 will also be updated.

[0087] If a certain amount of time has passed since the last refresh, the process proceeds to step SA4. In step SA4, the air supply control unit 27 opens the air passage on / off valve 455a and the discharge valve 453a, and closes the supply valve 452a. When the air passage on / off valve 455a is opened, the damper chamber 460a is opened to the atmosphere, allowing air to flow into the damper chamber 460a. Also, when the discharge valve 453a is opened, the damper chamber 460a communicates with the inside of the waste liquid bottle 251. In this state, the process proceeds to step SA5, and the process waits for a first predetermined time. The first predetermined time is not particularly limited, but can be, for example, a few seconds to about 10 seconds. During the waiting period, the ink in the damper chamber 460a flows through the second port 22d and the discharge passage 453 by its own weight and into the waste liquid bottle 251. Simultaneously, air flows from the third port 22e into the damper chamber 460a, bringing the ink level in the ink storage chamber R to an appropriate range. Specifically, air flows from the third port 22e into the damper chamber 460a to empty it once, and then, by performing purge control at an appropriate pressure, an appropriate amount of ink flows from the ink storage chamber R into the damper chamber 460a. In this way, the air supply control unit 27 performs refresh control again when a certain period of time has elapsed since the refresh control was performed, as stored in the timing memory unit 28.

[0088] In step SA6, the air supply control unit 27 closes the air flow path on / off valve 455a and the discharge valve 453a, and opens the supply valve 452a. It also stores the date and time of the refresh control in the timing storage unit 28. Subsequently, in step SA7, the drawing machine body 25 performs normal maintenance operations.

[0089] In this embodiment, in addition to gravity-based refreshing, pump refreshing using the air pump 455b can also be performed. Figure 19 shows the flow of air and ink when pump refreshing is being performed. Details of pump refreshing will be explained based on the flowchart shown in Figure 20. In step SB1, the user makes a maintenance start input. In step SB2, when the air supply control unit 27 detects that a maintenance start input has been made, it switches the drawing machine 2, which is drawing, to maintenance mode.

[0090] In step SB3, the air supply control unit 27 obtains the previous refresh date and time stored in the timing memory unit 28 and the current date and time. Based on the obtained previous refresh date and time and the current date, the air supply control unit 27 determines whether a certain amount of time (period) has elapsed since the previous refresh date and time. If a certain amount of time has not elapsed since the previous refresh date and time, the process proceeds to step SB8, and the drawing machine 2 performs normal maintenance operations without performing refresh control.

[0091] If a certain amount of time has passed since the last refresh, the process proceeds to step SB4. In step SA4, the air supply control unit 27 opens the air passage on / off valve 455a and the discharge valve 453a, and closes the supply valve 452a and the filter-side solenoid valve 454b. Then, the process proceeds to step SB5, where the air supply control unit 27 rotates the air pump 455b. This causes air to be pumped from the third port 22e into the damper chamber 460a.

[0092] In this state, the process proceeds to step SB6, where a second predetermined time is waited for. The second predetermined time is set to be shorter than the first predetermined time, and can be a short time, for example, about 1 second. During the waiting period, the ink in the damper chamber 460a flows through the second port 22d and the discharge channel 453 to the waste liquid bottle 251 due to the pressure of the air pump 455b. As a result, the liquid level of the ink in the ink storage chamber R is brought within an appropriate range. In this way, the air supply control unit 27 performs refresh control again when a certain period of time has elapsed since the refresh control was performed, as stored in the timing memory unit 28.

[0093] In step SB7, the air supply control unit 27 closes the air flow path on / off valve 455a and the discharge valve 453a, and opens the supply valve 452a and the filter-side solenoid valve 454b. It also stores the date and time of the refresh control in the timing storage unit 28. Subsequently, in step SB8, the drawing machine body 25 performs normal maintenance operations.

[0094] As shown in Figures 18 and 19, by incorporating refresh control into normal maintenance operations, the user does not need to perform a separate operation to perform refresh control. Alternatively, the user may perform an operation to perform refresh control, and the air supply control unit 27 may receive this operation and perform the refresh control. Furthermore, the display screen generation unit 40d may create a notification screen prompting the user to perform refresh control, and display the notification screen on the terminal-side display unit 5a. In other words, the display screen generation unit 40d and the terminal-side display unit 5a function as notification units that prompt the user to perform an operation to open the air flow path on / off valve 455a and supply air into the pressure fluctuation adjustment unit 460. In addition, the timing of refresh control may be determined based on the number of drawings and the amount of ink consumed since the last refresh control. For example, the air supply control unit 27 can determine whether the number of drawings since the last refresh control has exceeded a predetermined number and perform refresh control if it has exceeded the predetermined number, or it can determine whether the amount of ink consumed since the last refresh control has exceeded a predetermined amount and perform refresh control if it has exceeded the predetermined amount.

[0095] Furthermore, the air supply control unit 27 can detect whether the power of the drawing machine 2 is turned ON or OFF, and can perform refresh control when the power is turned ON or OFF.

[0096] Furthermore, the air passage valve 455a for supplying air to the pressure fluctuation adjustment unit 460 does not have to be a solenoid valve; it can be a manual valve. In that case, instead of the air supply control unit 27 controlling the opening of the air passage valve 455a, the user will manually open the air passage valve 455a. If it is determined in step SA3 of Figure 18 that the elapsed time since the last refresh is greater than a certain amount of time, the display screen generation unit 40d creates a notification screen prompting the user to manually open the air passage valve 455a, and the notification screen is displayed on the terminal-side display unit 5a. In other words, the display screen generation unit 40d and the terminal-side display unit 5a function as notification units that prompt the user to perform an operation to open the air passage valve 455a and supply air into the pressure fluctuation adjustment unit 460. By displaying the notification screen, the user can understand that time has passed since the last refresh and that it is necessary to operate the manual valve to refresh. The notification screen may be, for example, an error screen notifying that the pressure fluctuation suppression effect of the pressure fluctuation adjustment unit 460 has decreased.

[0097] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes that fall within the equivalent scope of the claims are all within the scope of the present invention. [Industrial applicability]

[0098] As described above, the drawing machine according to the present invention can be used, for example, to draw information on an object to be drawn on that is transported by a transporter. [Explanation of Symbols]

[0099] 2 drawing machine 20a Ink Tank 22 printheads 22a Nozzle group 22c Port 1 22d Port 2 22e Port 3 27 Air supply control unit 28 Timing memory unit 251 Waste liquid bottle (collection tank) 453 Discharge channel 453a Discharge valve (second solenoid valve) 455a Airflow channel on / off valve (first solenoid valve) 455b Air pump 460 Pressure fluctuation adjustment unit R Ink Storage Room

Claims

1. A drawing machine that ejects ink for drawing information onto an object to be drawn on, which is transported by a conveyor, An ink tank that holds the ink, A collection tank for collecting ink, A print head for ejecting ink from the first port toward an object being transported, comprising: a first port for receiving ink from the ink tank; a second port for discharging ink to the recovery tank; a pressure fluctuation adjustment unit positioned in the middle of the ink flow path between the first port and the second port; and a third port for receiving air supply to the pressure fluctuation adjustment unit, A first solenoid valve is positioned in the middle of an air passage for supplying air to the pressure fluctuation adjustment unit via the third port, and opens and closes the air passage. An air supply control unit that opens the first solenoid valve and supplies air into the pressure fluctuation adjustment unit, A drawing machine equipped with the following features.

2. In the drawing machine according to claim 1, The air supply control unit opens the first solenoid valve and supplies air into the pressure fluctuation adjustment unit when the print head is not ejecting ink, thereby enabling the drawing machine.

3. In the drawing machine according to claim 1, The device is equipped with a second solenoid valve positioned in the middle of a discharge channel that discharges the ink in the pressure fluctuation adjustment section to the recovery tank via the second port, and which opens and closes the discharge channel. The air supply control unit controls the opening of the first solenoid valve and the second solenoid valve when ink is not being ejected by the print head, in a drawing machine.

4. In the drawing machine according to claim 1, A drawing machine further comprising a pump that supplies air to the pressure fluctuation adjustment unit via the third port.

5. In the drawing machine according to claim 1, The system further includes a timing storage unit that stores the timing at which refresh control is performed by opening the first solenoid valve and supplying air into the pressure fluctuation adjustment unit. The air supply control unit performs refresh control again when a certain period of time has elapsed since the timing of the refresh control stored in the timing memory unit.

6. In the drawing machine according to claim 1, A drawing machine in which the discharge channel for discharging ink from the pressure fluctuation adjustment unit to the recovery tank via the second port is provided so as to have no undulations that oppose the direction of gravity.

7. In the drawing machine according to claim 1, In the print head, an ink storage chamber is formed in the middle of the ink flow path between the first port and the second port, for storing the ink ejected from the nozzle. The pressure fluctuation adjustment unit is interposed between the ink storage chamber and the second port in the drawing machine.

8. In the drawing machine according to claim 1, A drawing machine in which the pressure fluctuation adjustment unit contains ink flowing in from the ink tank and air, and the liquid surface of the contained ink is in contact with the air.

9. In the drawing machine according to claim 2, The printing machine is in maintenance mode when the print head is not ejecting ink.

10. A drawing machine that ejects ink for drawing information onto an object to be drawn on, which is transported by a conveyor, An ink tank that holds the ink, A collection tank for collecting ink, A print head for ejecting ink from the first port toward an object being transported, comprising: a first port for receiving ink from the ink tank; a second port for discharging ink to the recovery tank; a pressure fluctuation adjustment unit positioned in the middle of the ink flow path between the first port and the second port; and a third port for receiving air supply to the pressure fluctuation adjustment unit, A first valve is positioned in the middle of an air passage for supplying air to the pressure fluctuation adjustment unit via the third port, and opens and closes the air passage. A notification unit that provides notification regarding user operation for opening the first valve and supplying air into the pressure fluctuation adjustment unit, A drawing machine equipped with the following features.

Images