Droplet ejection device

Abstract

To provide a droplet discharge device which can form an image to be seen in a manner desired by a user.SOLUTION: A droplet discharge device comprises: a discharge head which discharges droplets on the basis of image data to a printing object medium having a discharge object surface including a parallel surface in parallel to a discharge surface and an inclined surface inclined with respect to the discharge surface; a distance detection device which detects a distance between the discharge surface and the parallel surface and a distance between the discharge surface and the inclined surface; and a control device. The control device acquires information about a printing mode selected by a user from the plurality of printing modes about discharge control of the droplets to the inclined surface when the discharge object surface to which the droplets should be discharged is the inclined surface from the detection result by the distance detection device, and performs discharge control of the droplets to the inclined surface on the basis of the printing mode selected by the user.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a droplet ejection device used in an image forming apparatus such as an inkjet printer.

Background Art

[0002] In addition to printing paper, the printed medium on which droplets are ejected by the droplet ejection device includes three-dimensional objects such as a mug and a smartphone case. Such three-dimensional objects may have an inclined surface. However, in a three-dimensional object where the distance from the ejection surface of the ejection head to the printed medium changes, droplet landing deviation occurs according to the distance. Therefore, in a part of the printed medium, the printed image is stretched.

[0003] Therefore, when forming an image on an inclined surface, it is disclosed to reduce the scale of the image corresponding to the inclined surface in the image data (see Patent Document 1). By reducing the scale of the image with respect to the inclined surface, it is said that the image when viewed from a direction perpendicular to the inclined surface can be made into a desired shape.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, even when an image is printed on an inclined surface of a three-dimensional object by the method described in Patent Document 1 above, there is a problem that the image appears shrunk when viewed from a direction perpendicular to the ejection surface.

[0006] Therefore, an object of the present invention is to provide a droplet ejection device capable of forming an image that looks as desired by the user.

Means for Solving the Problems

[0007] The droplet ejection device of the present invention comprises an ejection head that ejects droplets onto a printing medium having an ejection surface including a parallel surface parallel to the ejection surface and an inclined surface inclined with respect to the ejection surface, based on image data; a distance detection device that detects the distance between the ejection surface and the parallel surface, and the distance between the ejection surface and the inclined surface; and a control device. The control device, based on the detection result by the distance detection device, obtains information regarding a printing mode selected by the user from among a plurality of printing modes for controlling the ejection of droplets onto the inclined surface, when the ejection surface from which the droplets should be ejected is the inclined surface, and performs droplet ejection control onto the inclined surface based on the printing mode selected by the user.

[0008] According to the present invention, droplets are ejected onto an inclined surface based on the printing mode selected by the user, thereby forming an image on the inclined surface that appears as desired by the user. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a droplet dispensing device that prevents the occurrence of areas where droplets should land but where the droplets do not land (blank areas). [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing an image forming apparatus equipped with a droplet ejection device according to one embodiment of the present invention. [Figure 2] This is a plan view showing a droplet dispensing device according to one embodiment of the present invention. [Figure 3] Figure 1 is a cross-sectional view showing the configuration of the discharge head. [Figure 4] This is a block diagram showing the components of the image forming apparatus shown in Figure 1. [Figure 5] This diagram illustrates the conventional challenges. [Figure 6] This is a diagram illustrating the first printing mode. [Figure 7] This is a diagram of the review screen showing the printing behavior on the printing medium based on the first printing mode. [Figure 8] This is a diagram illustrating the second printing mode. [Figure 9] Figure 9A shows the review screen when the printing medium is viewed from a direction perpendicular to the parallel surface in the second printing mode, and Figure 9B shows the review screen when the printing medium is viewed from a direction perpendicular to the inclined surface in the second printing mode. [Figure 10] Figure 10A shows a printing medium where the angle between the inclined surface and the ejection surface is a first angle, and Figure 10B shows a printing medium where the angle between the inclined surface and the ejection surface is a second angle, which is greater than the first angle. [Figure 11] Figure 11A shows a drive waveform with four discharge pulses in one drive cycle, and Figure 11B shows a drive waveform with five discharge pulses in one drive cycle. [Figure 12] This is a diagram illustrating an example of the third printing mode. [Figure 13] This is a diagram illustrating another example of the third printing mode. [Figure 14A] This is a plan view illustrating discharge control on inclined and parallel surfaces aligned in the conveying direction. [Figure 14B] This is a side view of Figure 14A. [Modes for carrying out the invention]

[0011] Hereinafter, a droplet dispensing device according to an embodiment of the present invention will be described with reference to the drawings. The droplet dispensing device described below is merely one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiments, and additions, deletions, and modifications are possible without departing from the spirit of the present invention.

[0012] FIG. 1 is a perspective view showing an image forming apparatus 1 provided with a droplet discharge device 1a according to an embodiment of the present invention. In FIG. 1, the directions orthogonal to each other are defined as the first direction Ds, the second direction Df, and the third direction Dz. In the present embodiment, for example, the first direction Ds is the moving direction of a carriage 3 described later, the second direction Df is the conveyance direction of a printing medium W described later, and the third direction Dz is the vertical direction. In the following description, Ds is referred to as the moving direction, and Df is referred to as the conveyance direction.

[0013] As shown in FIG. 1, the image forming apparatus 1 of the present embodiment includes a housing 2, an operation key 4, a display unit 5, a platen 6 on which a printing medium W is disposed, and an upper cover 7. The platen 6 corresponds to a conveyance unit. Further, the image forming apparatus 1 includes a droplet discharge device 1a shown in FIG. 2 having a discharge head 10 and a controller unit 19 including a control device 20 (FIG. 4). The discharge head 10 is an inkjet head that discharges, for example, ultraviolet-curable ink droplets as droplets.

[0014] The housing 2 is formed in a box shape. The housing 2 has an opening 2a. An operation key 4 is provided on the housing 2. Further, a display unit 5 is provided near the operation key 4. The operation key 4 receives an operation input by a user. The display unit 5 is configured by, for example, a touch panel and displays predetermined information. A part of the display unit 5 also functions as an operation key. The controller unit 19 realizes a printing function based on an input from the operation key 4 or an external input via a communication interface (not shown) and controls the display of the display unit 5.

[0015] [[ID=II]] The platen 6 is configured to be able to place the printing medium W thereon. The platen 6 has a predetermined thickness and is formed of, for example, a rectangular plate material with the conveyance direction Df as the longitudinal direction. The platen 6 is removably supported by a platen support base (not shown). The platen support base is configured to be movable in the conveyance direction Df between a printing position where printing on the printing medium W is performed by driving of the conveyance motor 33 (FIG. 4) and a detachment position where the printing medium W is removed from the platen 6. Thereby, the platen 6 relatively moves the discharge surface of the printing medium W in the conveyance direction Df with respect to the discharge head 10. Since the platen 6 moves in the conveyance direction Df during printing, the printing medium W placed on the platen 6 is conveyed along the conveyance direction Df.

[0016] The upper cover 7 is configured to rotate upward when its end is lifted. Thereby, the inside of the housing 2 is exposed.

[0017] As shown in FIG. 2, the droplet discharge device 1a includes a storage tank 62, a carriage 3 on which, for example, two discharge heads 10 (10A, 10B) and two ultraviolet irradiation devices 40 (40A, 40B) are mounted, and a pair of guide rails 67. Although two discharge heads 10 and two ultraviolet irradiation devices 40 are provided, the present invention is not limited thereto, and one discharge head 10 and one ultraviolet irradiation device 40 may be provided.

[0018] The carriage 3 is supported by a pair of guide rails 67 extending in the moving direction Ds and reciprocates in the moving direction Ds along the guide rails 67. Thereby, the two discharge heads 10 (10A, 10B) and the two ultraviolet irradiation devices 40 (40A, 40B) can reciprocate in the moving direction Ds. Further, the discharge head 10 is connected to the storage tank 62 via a tube 62a.

[0019] In this embodiment, for example, the ejection head 10A ejects ink droplets of yellow (Y), magenta (M), cyan (C), and black (K), which are sometimes collectively referred to as color inks. A color image is printed on the printing medium W by ejecting these four ink droplets onto the printing medium W. On the other hand, the ejection head 10B ejects white (W) ink droplets and clear (Cr) ink droplets. When printing a color image on a fabric, for example, as the printing medium W, in order to reduce the influence on the color and material of the fabric, white ink droplets are ejected first as a base ink, and then color ink droplets are ejected on top of the white ink droplets. Clear ink droplets are ejected when gloss is to be added or when the printed area is to be protected.

[0020] The storage tanks 62 store ink. Each storage tank 62 is provided for a different type of ink. For example, six storage tanks 62 are provided, each storing black, yellow, cyan, magenta, white, and clear ink.

[0021] The droplet dispensing device 1a further includes a purge section 50 and a wipe section 54. The purge section 50 and the wipe section 54 are positioned on one end of a pair of guide rails 67 in the direction of movement Ds, so as to overlap with the movement area of ​​the carriage 3.

[0022] The purging unit 50 includes a cap 51, a suction pump 52, and a lifting mechanism 53. The suction pump 52 is connected to the cap 51. The lifting mechanism 53 raises and lowers the cap 51 between a suction position and a standby position. In the standby position, the discharge surface NM (Figure 3) is separated from the cap 51. On the other hand, in the suction position, the discharge surface NM is covered by the cap 51, forming a sealed space. When the suction pump 52 is driven while the cap 51 is in the suction position, the sealed space is sucked in, and a purging process is performed in which ink is discharged from the nozzle hole 121a (Figure 3), which will be described later.

[0023] The wipe section 54 also has two wipers 55 and 56 and a moving mechanism 57. The two wipers 55 and 56 are supported by the moving mechanism 57. The moving mechanism 57 moves in the transport direction Df with the discharge surface NM positioned facing these wipers 55 and 56. As a result, the two wipers 55 and 56 perform a wiping operation (i.e., wiping the discharge surface NM) while moving in the transport direction Df.

[0024] Next, the detailed structure of the discharge head 10 will be described. As shown in Figure 3, the discharge head 10 has a plurality of nozzles 121 that discharge ink droplets using ink from the storage tank 62. The discharge head 10 has a laminate of a flow channel forming body and a volume changing body. An ink flow channel is formed inside the flow channel forming body, and a plurality of nozzle holes 121a open on its lower surface, the discharge surface NM. The volume changing body is driven to change the volume of the ink flow channel. At this time, the meniscus vibrates in the nozzle holes 121a and ink is discharged.

[0025] The flow path forming body of the discharge head 10 is a laminate of multiple plates, and the volume changing section includes a diaphragm 155 and an actuator (piezoelectric element) 160. A common electrode 161, described later, is connected to the diaphragm 155.

[0026] Multiple plates are stacked, from bottom to top, including a nozzle plate 146, a spacer plate 147, a first channel plate 148, a second channel plate 149, a third channel plate 150, a fourth channel plate 151, a fifth channel plate 152, a sixth channel plate 153, and a seventh channel plate 154.

[0027] Each plate has holes and grooves of various sizes formed in it. Inside the flow channel forming body formed by stacking the plates, the holes and grooves are combined to form multiple nozzles 121, multiple individual flow channels 164, and a manifold 122 as ink flow channels.

[0028] The nozzle 121 is formed by penetrating the nozzle plate 146 in the stacking direction. On the discharge surface NM of the nozzle plate 146, multiple nozzle holes 121a, which are the tips of the nozzles 121, are arranged in the transport direction Df to form a nozzle row.

[0029] The manifold 122 supplies ink to the pressure chamber 128 to which discharge pressure is applied. The manifold 122 extends in the transport direction Df and is connected to one end of each of the multiple individual flow channels 164. In other words, the manifold 122 functions as a common flow channel for the ink. The manifold 122 is formed by through holes that penetrate the first flow channel plates 148 to the fourth flow channel plates 151 in the stacking direction, and recesses that are recessed from the lower surface of the fifth flow channel plate 152, overlapping in the stacking direction.

[0030] The nozzle plate 146 is positioned below the spacer plate 147. The spacer plate 147 is made of, for example, stainless steel. The spacer plate 147 has a recess 145 formed by, for example, half-etching, which causes a recess in the thickness direction of the spacer plate 147 from the surface facing the nozzle plate 146, thereby forming a thin-walled portion that forms a damper portion 147a and a damper space 147b. As a result, a damper space 147b is formed between the manifold 122 and the nozzle plate 146, acting as a buffer space.

[0031] A supply port 122a is connected to the manifold 122. The supply port 122a is formed, for example, in a cylindrical shape and is provided at one end in the conveying direction Df. The manifold 122 and the supply port 122a are connected by a flow path not shown in the figure.

[0032] Each individual flow path 164 is connected to the manifold 122. The upstream end of each individual flow path 164 is connected to the manifold 122, and the downstream end is connected to the base end of the nozzle 121. Each individual flow path 164 consists of a first communication hole 125, an individual throttling passage which is a supply throttling passage 126, a second communication hole 127, a pressure chamber 128, and a descender 129, and these components are arranged in this order.

[0033] The first communication hole 125 has its lower end connected to the upper end of the manifold 122, extends upward from the manifold 122 in the stacking direction, and penetrates the upper portion of the fifth flow path plate 152 in the stacking direction.

[0034] The upstream end of the supply throttling passage 126 is connected to the upper end of the first communication hole 125. The supply throttling passage 126 is formed, for example, by half-etching and consists of a groove recessed from the lower surface of the sixth flow channel plate 153. The second communication hole 127 has its upstream end connected to the downstream end of the supply throttling passage 126, extends upward from the supply throttling passage 126 in the stacking direction, and is formed by penetrating the sixth flow channel plate 153 in the stacking direction.

[0035] The pressure chamber 128 has its upstream end connected to the downstream end of the second communication hole 127. The pressure chamber 128 is formed by penetrating the seventh flow channel plate 154 in the stacking direction.

[0036] The descender 129 is formed by penetrating the spacer plate 147, the first flow path plate 148, the second flow path plate 149, the third flow path plate 150, the fourth flow path plate 151, the fifth flow path plate 152, and the sixth flow path plate 153 in the stacking direction. The upstream end of the descender 129 is connected to the downstream end of the pressure chamber 128, and the downstream end is connected to the base end of the nozzle 121. The nozzle 121 overlaps the descender 129 in the stacking direction, for example, and is positioned in the center of the descender 129 in the width direction.

[0037] The diaphragm 155 is laminated on the seventh flow path plate 154 and covers the upper end opening of the pressure chamber 128.

[0038] The actuator 160 includes a common electrode 161, a piezoelectric layer 162, and individual electrodes 163, arranged in this order. The common electrode 161 covers the entire surface of the diaphragm 155. The piezoelectric layer 162 covers the entire surface of the common electrode 161. Individual electrodes 163 are provided for each pressure chamber 128 and are arranged on the piezoelectric layer 162. One actuator 160 is composed of one individual electrode 163, the common electrode 161, and the portion of the piezoelectric layer 162 sandwiched between the two electrodes.

[0039] The individual electrodes 163 are electrically connected to a driver IC. This driver IC receives a control signal from the control device 20, generates a drive signal (voltage signal), and applies it to the individual electrodes 163. In contrast, the common electrode 161 is always kept at ground potential. In this configuration, the active portion of the piezoelectric layer 162 expands and contracts in the planar direction together with the common electrode 161 and the individual electrodes 163 in response to the drive signal. Accordingly, the diaphragm 155 deforms in cooperation, changing the volume of the pressure chamber 128 in a direction that increases or decreases it. As a result, the discharge pressure that causes ink droplets to be ejected from the nozzle 121 is applied to the pressure chamber 128.

[0040] In the ejection head 10, ink flows into the manifold 122 via the supply port 122a, then flows from the manifold 122 into the supply throttling passage 126 via the first communication hole 125, and from the supply throttling passage 126 into the pressure chamber 128 via the second communication hole 127. The ink then flows through the descender 129 and into the nozzle 121. At this point, when ejection pressure is applied to the pressure chamber 128 by the actuator 160, ink droplets are ejected from the nozzle hole 121a.

[0041] As shown in Figure 4, in addition to the components described above, the image forming apparatus 1 includes a controller unit 19, a reader 26, motor driver ICs 30 and 31, head driver ICs 32 and 35, a transport motor 33, a carriage motor 34, an illumination device driver ICs 36 and 37, a purge driver IC 38, a wipe driver IC 39, and a 3D camera 58. The 3D camera 58 corresponds to a distance detection device.

[0042] The controller unit 19 includes a control device 20 composed of a CPU, a storage unit (ROM 21, RAM 22, EEPROM 23, HDD 24), and an ASIC 25. The control device 20 is connected to each of the above-mentioned storage units and controls the driver ICs 30-32, 35-39 and the display unit 5.

[0043] The control device 20 performs various functions by executing a predetermined processing program stored in the ROM 21. The control device 20 may be implemented as a single processor in the controller unit 19, or as multiple processors working together. The processing program is read by the reader 26 from a recording medium KB such as a computer-readable magneto-optical disk or USB flash memory and stored in the ROM 21. The RAM 22 stores image data received from an external source and the calculation results of the control device 20. The EEPROM 23 stores various initial setting information entered by the user. The HDD 24 stores specific information, etc.

[0044] The ASIC25 is connected to motor driver ICs 30 and 31, head driver ICs 32 and 35, irradiation device driver ICs 36 and 37, purge driver IC 38, wipe driver 39, and 3D camera 58. When the control device 20 receives a print job from the user, it outputs an image recording command to the ASIC25 based on the processing program. The ASIC25 drives each driver IC 30-32 and 35-39 based on the image recording command. The control device 20 moves the platen 6 in the transport direction Df by driving the transport motor 33 with the motor driver IC 30. The control device 20 moves the carriage 3 in the movement direction Ds by driving the carriage motor 34 with the motor driver IC 31.

[0045] The control device 20 converts image data acquired from external devices, etc., into ejection data for ejecting ink droplets onto the ejection surface. Based on the converted ejection data, the control device 20 ejects ink droplets from the ejection head 10 using head driver ICs 32 and 35. The control device 20 also irradiates ultraviolet light from the light-emitting diode chips of the ultraviolet irradiation devices 40A and 40B using irradiation device driver ICs 36 and 37. The control device 20 drives the suction pump 52 and lifting mechanism 53 of the purge unit 50 using the purge driver IC 38. The control device 20 drives the movement mechanism 57 of the wipe unit 54 using the wipe driver IC 39. The 3D camera 58 detects the distance H1 (Figure 5) between the ejection surface NM of the ejection head 10 and the parallel surface HM of the printing medium W, and the distance H2 (Figure 5) between the ejection surface NM and the inclined surfaces KM1 and KM2. The control device 20 acquires the detection results detected by the 3D camera 58.

[0046] As shown in Figure 5, the droplet ejection device 1a can eject ink droplets Dt onto a printing medium W consisting of a three-dimensional object. The printing medium W has an ejection surface WM onto which the ink droplets Dt are ejected. The ejection surface WM includes a parallel surface HM parallel to the ejection surface NM and inclined surfaces KM1 and KM2 inclined with respect to the ejection surface NM. The inclined surface KM1 is located on one side of the parallel surface HM in a first direction D1 parallel to the parallel surface HM. The inclined surface KM2 is located on the other side of the parallel surface HM in the first direction D1.

[0047] As the ejection head 10 ejects ink droplets Dt, the carriage 3 moves in the direction Ds. Therefore, the ink droplets Dt ejected from the ejection head 10 do not fly along the ejection direction Dv perpendicular to the ejection surface NM, but actually fly in a direction inclined with respect to the ejection surface NM. As a result, misalignment of the ink droplets Dt occurs. Therefore, as shown in Figure 5, it is conceivable to control the operation of the ejection head 10 so that the pitch Pk between adjacent ink droplets Dt on the inclined surface KM1 and the pitch Ph between adjacent ink droplets Dt on the parallel surface HM are the same when viewed from the ejection direction Dv. However, when the printing medium W is viewed from a direction perpendicular to the inclined surface KM1, the image formed on the inclined surface KM1 may appear stretched. Therefore, the droplet ejection device 1a of this embodiment is provided with multiple printing modes for controlling the ejection of ink droplets Dt to the inclined surfaces KM1 and KM2. The user can select one of the multiple printing modes using the operation key 4 or the like before starting printing. There are three print modes: the first print mode, the second print mode, and the third print mode. Each print mode is described below.

[0048] Figure 6 is a diagram illustrating the first printing mode. In the explanation of Figure 6, it is assumed that the user has selected the first printing mode. Before printing based on the first printing mode selected by the user begins, the 3D camera 58 detects the distance between the ejection surface NM of the ejection head 10 and the parallel surface HM of the printing medium W, and the distances between the ejection surface NM and the inclined surfaces KM1 and KM2 of the printing medium W.

[0049] The control device 20 receives the detection results from the 3D camera 58. If the surface WM from which the ink droplet Dt should be ejected is an inclined surface KM1 or KM2, the control device 20 obtains information about the inclined surfaces KM1 or KM2 from the RAM 22 for the first printing mode and performs ejection control based on the first printing mode. The same applies to the second and third printing modes described later.

[0050] The first printing mode is a mode in which, as shown in Figure 6, the pitch P11 of adjacent ink droplets Dt on inclined surfaces KM1 and KM2 in the first direction D1 parallel to the parallel surface HM is the same as the pitch P12 of adjacent ink droplets Dt on the parallel surface HM in the first direction D1. According to the first printing mode, when the printing medium W is viewed from the ejection direction Dv, distortion or stretching of the image on inclined surfaces KM1 and KM2 is prevented or suppressed. As a result, the first printing mode is an effective printing mode when the printing medium W is often viewed from a relatively long distance, for example, when the printing medium W is a sign or the like.

[0051] Here, as shown in Figure 7, after the user selects a first printing mode, a review screen 5r showing the printing pattern on the printing medium W based on the selected first printing mode is displayed on the display unit 5. At this time, the control device 20 outputs image data of the review screen 5r to the ASIC 25. For example, suppose the image data is the characters "ABC", with "A" printed on the inclined surface KM1, "B" printed on the parallel surface HM, and "C" printed on the inclined surface KM2. In this case, the user can visually confirm the printing pattern on the inclined surface KM1, the parallel surface HM, and the inclined surface KM2 of the printing medium W on the review screen 5r. As shown in Figure 7, the images on the inclined surfaces KM1 and KM2 do not appear distorted or stretched. In this way, the user can check the printing pattern on the printing medium W in advance on the review screen 5r before printing begins. The control device 20 outputs image data after detecting the distance using the 3D camera 58 while moving the carriage 3 in the movement direction Ds. As a result, a review screen 5r showing the printing pattern of the entire printing medium W is displayed on the display unit 5.

[0052] Next, we will explain the second printing mode. Figure 8 is a diagram illustrating the second printing mode.

[0053] The second printing mode is a mode in which, as shown in Figure 8, the pitch P2 of adjacent ink droplets Dt on the inclined surface KM1 in the second direction D21 parallel to the inclined surface KM1 is the same as the pitch P12 of adjacent ink droplets Dt on the parallel surface HM in the first direction D1. Similarly, the pitch P2 of adjacent ink droplets Dt on the inclined surface KM2 in the second direction D22 parallel to the inclined surface KM2 is the same as the pitch P12 of adjacent ink droplets Dt on the parallel surface HM in the first direction D1. According to the second printing mode, when the printing medium W is viewed from a direction perpendicular to the inclined surface KM1, distortion or stretching of the image on the inclined surface KM1 is prevented or suppressed. As a result, the second printing mode is an effective printing mode when printing on a printing medium W with a relatively large number of inclined surfaces, such as a mug.

[0054] As shown in Figure 9, after the user selects a second printing mode from among several printing modes, a review screen 5r showing the printing pattern on the printing medium W based on the selected second printing mode is displayed on the display unit 5. In Figures 9A and 9B, for example, if the image data is the characters "ABC", the user can visually confirm the printing pattern on the inclined surface KM1, the parallel surface HM, and the inclined surface KM2 of the printing medium W.

[0055] The display unit 5 can display a review screen 5r (Figure 9A) when the printing medium W is viewed from a direction perpendicular to the parallel surface HM, and a review screen 5r (Figure 9B) when the printing medium W is viewed from a direction perpendicular to the inclined surface KM1. As shown in Figure 9A, when the printing medium W is viewed from a direction perpendicular to the parallel surface HM, the images on the inclined surfaces KM1 and KM2 appear compressed. On the other hand, as shown in Figure 9B, when the printing medium W is viewed from a direction perpendicular to the inclined surface KM1, the image on the parallel surface HM appears compressed, but the image on the inclined surface KM1 does not appear compressed. When the printing medium W is viewed from a direction perpendicular to the inclined surface KM1, the image on the inclined surface KM2 ("C") is not visible, so the image may be displayed as a dotted line on the review screen 5r. In addition, the image of the inclined surface KM2 when the printing medium W is viewed from a direction perpendicular to the inclined surface KM2 may be displayed on the review screen 5r, and the image of the inclined surface KM1 when the printing medium W is viewed from a direction perpendicular to the inclined surface KM1 may be displayed as a dotted line.

[0056] After the user confirms the print output on the review screen 5r, a screen may be displayed on the display unit 5 that allows the user to arbitrarily input the print resolution for the inclined surfaces KM1 and KM2. In this case, the control device 20 acquires the resolution input information arbitrarily entered by the user for the print resolution for the inclined surfaces KM1 and KM2, and outputs image data based on this resolution input information to the ASIC 25. The ASIC 25 displays the image data based on the resolution input information on the display unit 5. This allows the user to confirm the print output based on the arbitrary resolution input information they entered on the display unit 5.

[0057] In the second printing mode, the control device 20 controls the operation of the ejection head 10 to change the print resolution of the inclined surface KM1 according to the angle that the inclined surface KM1 makes with the ejection surface NM. This will be explained in detail below. The print resolution described below refers to the print resolution when the printing medium W is viewed from a direction perpendicular to the ejection surface NM.

[0058] The printing medium W shown in Figure 10A includes an inclined surface KM11 with an angle of first angle α1 with respect to the ejection surface NM, a parallel surface HM, and an inclined surface KM21. The angle that inclined surface KM21 makes with respect to the ejection surface NM is also α1. Inclined surfaces KM11 and KM21 correspond to the first inclined surface. On the other hand, the printing medium W shown in Figure 10B includes an inclined surface KM12 with an angle of second angle α2, which is greater than the first angle α1 with respect to the ejection surface NM, a parallel surface HM, and an inclined surface KM22. The angle that inclined surface KM22 makes with respect to

[0059] In the second printing mode, the control device 20 controls the operation of the ejection head 10 so that the printing resolution of the inclined surface KM12 is higher than that of the inclined surface KM11. At this time, the control device 20 reduces the movement speed of the carriage 3 when printing on the inclined surface KM12 compared to when printing on the inclined surface KM11. This makes it possible to make the printing resolution of the inclined surface KM12 higher than that of the inclined surface KM11. Similarly, in the second printing mode, the control device 20 controls the operation of the ejection head 10 so that the printing resolution of the inclined surface KM22 is higher than that of the inclined surface KM21.

[0060] In the second printing mode, when the printing resolution of the inclined surface KM12 is to be higher than that of the inclined surface KM11, the control device 20 may perform the following control. That is, when printing on the inclined surface KM12, the control device 20 increases the number of ejection pulses in one drive cycle of the drive waveform that drives the actuator 160 compared to when printing on the inclined surface KM11. Specifically, when printing on the inclined surface KM11, the control device 20 controls the operation of the ejection head 10 using a drive waveform Wp1 in which the number of ejection pulses Pd in ​​one drive cycle is, for example, four, as shown in Figure 11A. In contrast, when printing on the inclined surface KM12, the control device 20 controls the operation of the ejection head 10 using a drive waveform Wp2 in which the number of ejection pulses Pd in ​​one drive cycle is, for example, five, as shown in Figure 11B. This makes it possible to make the printing resolution of the inclined surface KM12 higher than that of the inclined surface KM11. The same control is applied when the printing resolution of the inclined surface KM22 is to be higher than that of the inclined surface KM21.

[0061] The control device 20 may determine an upper limit for the angle α1 formed by the inclined surface KM11 and the ejection surface NM. In this case, the control device 20 can determine the upper limit based on the ratio of the printing resolution required for the parallel surface HM based on the image data and the maximum printing resolution on the parallel surface HM determined based on the movement resolution of the carriage 3. For example, if the angle α1 is 75°, the ratio of the length of the inclined surface KM1 to the length of the parallel surface HM becomes 4, and the printing resolution required for the inclined surface KM1 becomes 4 times the printing resolution of the parallel surface HM. Therefore, it is difficult to print on the inclined surface KM1 based on the above printing resolution. Thus, the upper limit for the angle α1 formed by the inclined surface KM11 and the ejection surface NM can be set to, for example, 75°.

[0062] Next, the third printing mode will be explained. Figures 12 and 13 are diagrams illustrating the third printing mode.

[0063] As shown in Figure 12, in the third printing mode, the operation of the ejection head 10 is controlled so that the volume of ink droplets Dtb to be ejected onto the inclined surfaces KM1 and KM2 is greater than the volume of ink droplets Dt to be ejected onto the parallel surface HM. Similar to the first printing mode, the pitch P11 in the first direction D1 between adjacent ink droplets Dt on the inclined surfaces KM1 and KM2 is the same as the pitch P12 in the first direction D1 between adjacent ink droplets Dt on the parallel surface HM. Furthermore, by ejecting ink droplets Dtb onto the inclined surfaces KM1 and KM2, the spacing SP1 between ink droplets Dtb on each inclined surface KM1 and KM2 can be made the same as the spacing SP2 between ink droplets Dt on the parallel surface HM. This third printing mode, in addition to the effect of the first printing mode which suppresses the stretching of images on inclined surfaces KM1 and KM2 when the printing medium W is viewed from the ejection direction Dv, makes the difference in image density less noticeable when the printing medium W is viewed from a direction perpendicular to the inclined surfaces KM1 and KM2, because the above-mentioned intervals SP1 and SP2 are the same.

[0064] In the third printing mode, the control device 20 may perform the following control instead of, or in conjunction with, the above-described process of ejecting ink droplets Dt with a volume larger than the volume of ink droplets Dt to be ejected onto the parallel surface HM onto the inclined surfaces KM1 and KM2. That is, as shown in Figure 13, the control device 20 may control the operation of the ejection head 10 so that the number of ink droplets Dt per unit area to be ejected onto the inclined surfaces KM1 and KM2 is greater than the number of ink droplets Dt per unit area to be ejected onto the parallel surface HM. In this case, multiple ink droplets Dts with a volume smaller than ink droplet Dt may be ejected onto the inclined surfaces KM1 and KM2. Even with such a process, the difference in density of the image becomes less noticeable when the printing medium W is viewed from a direction perpendicular to the inclined surfaces KM1 and KM2. In addition, similar to the second printing mode, in the third printing mode, the control device 20 may control the operation of the ejection head 10 to change the printing resolution of the inclined surfaces KM1 and KM2 according to the angle that the inclined surfaces KM1 and KM2 make with the ejection surface NM.

[0065] Next, even for a printing medium W with an inclined surface in the transport direction Df, printing can be performed to increase the printing resolution of the inclined surface compared to the printing resolution of the parallel surface. Figure 14A is a plan view illustrating the ejection control on the inclined surface KM1 and the parallel surface HM aligned in the transport direction Df.

[0066] The control device 20 controls the operation of the carriage 3 and the ejection head 10 so that multiple pass prints are performed on the inclined surface KM1. Specifically, the control device 20 controls the operation of the carriage 3 and the ejection head 10 so that the number of pass prints on the inclined surface KM1 is greater than the number of pass prints on the parallel surface HM. Specifically, as shown in Figure 14A, the control device 20 causes the ejection head 10 to perform, for example, four pass prints on the inclined surface KM11 and, for example, two pass prints on the parallel surface HM. In this way, by performing more pass prints on the inclined surface KM1 than on the parallel surface HM, the print resolution of the inclined surface KM1 aligned with the parallel surface HM in the transport direction Df can be made higher than the print resolution of the parallel surface HM.

[0067] As explained above, with the droplet ejection device 1a, ink droplets Dt are ejected onto the inclined surfaces KM1 and KM2 based on the printing mode selected by the user, so that an image that looks as desired by the user can be formed on the inclined surfaces KM1 and KM2.

[0068] Furthermore, in this embodiment, the print modes include a first print mode and a second print mode. In this case, the user can select either the first print mode or the second print mode from among the multiple print modes based on the main direction in which the print medium W is viewed. This helps to suppress the image from appearing stretched or compressed.

[0069] Furthermore, in this embodiment, in the second printing mode, the printing resolution of the inclined surfaces KM1 and KM2 in the direction perpendicular to the ejection surface NM is changed according to the angle that the inclined surfaces KM1 and KM2 make with the ejection surface NM. This makes it possible to achieve an appropriate printing resolution according to the angle of the inclined surfaces KM1 and KM2 with respect to the ejection surface NM.

[0070] Furthermore, in this embodiment, the control device 20 controls the operation of the ejection head 10 so that in the second printing mode, the printing resolution of the inclined surface KM12 is higher than that of the inclined surface KM11, and the printing resolution of the inclined surface KM22 is higher than that of the inclined surface KM21. This makes it possible to adjust the printing resolution of the inclined surface appropriately as the angle increases.

[0071] Furthermore, in this embodiment, when the control device 20 increases the printing resolution of the inclined surface KM12 in the second printing mode compared to the printing resolution of the inclined surface KM11, it reduces the movement speed of the carriage 3 compared to when printing on the inclined surface KM11. Alternatively, in the above case, the control device 20 increases the number of ejection pulses Pd within one drive cycle in the drive waveform Wp2 that drives the actuator 160 compared to the drive waveform Wp1 used when printing on the inclined surface KM11. In this case, the printing resolution can be easily increased.

[0072] Furthermore, in this embodiment, a third printing mode is included in the printing modes. In this case, the spacing between adjacent ink droplets Dt on inclined surfaces KM1 and KM2 can be made the same as the spacing between adjacent ink droplets Dt on parallel surface HM. This makes it less likely for differences in density to occur depending on the viewing angle of the printing medium W. In addition, by ejecting ink droplets Dtb with a large volume, the printing time can be shortened compared to when many ink droplets Dt are ejected.

[0073] Furthermore, in this embodiment, the control device 20 may, in the third printing mode, perform the following control instead of, or in conjunction with, the process of ejecting ink droplets Dtb with a volume larger than the volume of ink droplets Dt to be ejected onto the parallel surface HM onto the inclined surfaces KM1 and KM2. That is, the control device 20 may control the operation of the ejection head 10 so that the number of ink droplets Dt per unit area to be ejected onto the inclined surfaces KM1 and KM2 is greater than the number of ink droplets Dt per unit area to be ejected onto the parallel surface HM. In this case, by ejecting a large number of ink droplets Dt, the image can be formed more clearly and finely than when ejecting large volume droplets Dtb.

[0074] Furthermore, in this embodiment, the control device 20 controls the operation of the ejection head 10 in the third printing mode so that the volume or number of ink droplets Dt to be ejected onto the inclined surfaces KM1 and KM2 changes according to the angle that the inclined surfaces KM1 and KM2 make with the ejection surface NM. In this case, an appropriate image can be formed that is less likely to produce differences in density depending on the angle of the inclined surfaces KM1 and KM2 with respect to the ejection surface NM.

[0075] Furthermore, in this embodiment, the control device 20 may control the operation of the ejection head 10 so that the volume of ink droplets Dt to be ejected increases as the angle of the inclined surfaces KM1 and KM2 with respect to the ejection surface NM increases in the third printing mode. Alternatively, the control device 20 may control the operation of the ejection head 10 so that the number of ink droplets Dt to be ejected increases as the angle of the inclined surfaces KM1 and KM2 with respect to the ejection surface NM increases in the third printing mode. Generally, when the inclination angle of an inclined surface is large, the number of droplets that land on the inclined surface decreases, and therefore the arrangement density of ink droplets Dt on the inclined surface decreases. In contrast, in this embodiment, as the angle increases, larger volume ink droplets Dt are ejected, or a large number of ink droplets Dt are ejected, so a decrease in the arrangement density of ink droplets Dt on the inclined surfaces KM1 and KM2 can be prevented.

[0076] Furthermore, in this embodiment, when the inclined surface KM1 and parallel surface HM of the printing medium W are provided along the transport direction Df, the control device 20 controls the operation of the carriage 3 and the ejection head 10 to perform multiple pass printing on the inclined surface KM1. This makes it possible to form an image on the inclined surface KM1 that looks as desired by the user, even when printing on the printing medium W where the inclined surface KM1 is located in the transport direction Df.

[0077] Furthermore, in this embodiment, the control device 20 controls the operation of the carriage 3 and the ejection head 10 so that the number of pass prints on the inclined surface KM1 is greater than the number of pass prints on the parallel surface HM. This prevents the image from becoming stretched when the inclined surface KM1 is viewed from a direction perpendicular to the inclined surface KM1.

[0078] Furthermore, in this embodiment, a review screen 5r showing the printing pattern is displayed on the display unit 5 before printing begins. In this case, the user can check the printing pattern on the printing medium W in advance on the review screen 5r before printing starts.

[0079] In this embodiment, the control device 20 moves the carriage 3 in the direction Ds while detecting distances H1 and H2 using the 3D camera 58, and then outputs image data. In this case, a review screen 5r showing the printing pattern of the entire printing medium W can be displayed.

[0080] Furthermore, in this embodiment, the user can arbitrarily input the print resolution for the inclined surfaces KM1 and KM2. This allows the user to check the review screen 5r and manually correct the print resolution if there are problems with the printing pattern.

[0081] Furthermore, in this embodiment, the control device 20 determines the upper limit of the angle α1 formed by the inclined surface KM11 and the ejection surface NM. In this case, printing can be performed while knowing in advance the limit of the angle α1 that can achieve the desired printing resolution.

[0082] (modified version) The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. For example, the following:

[0083] In the above embodiment, the distance H1 between the discharge surface NM and the parallel surface HM, and the distance H2 between the discharge surface NM and the inclined surfaces KM1 and KM2 are detected by the 3D camera 58, but the system is not limited to this. For example, the user may input the distances H1 and H2, store this input information in the memory unit, and the control device 20 may acquire the stored information. Alternatively, the distances may be detected by a distance detection device such as a 3D scanner.

[0084] Furthermore, in the above embodiment, only two inclined surfaces KM1 and KM2 were provided on the printing medium W, but the number of inclined surfaces may be one or three or more.

[0085] Furthermore, in the above embodiment, an ink droplet with a smaller volume than ink droplet Dt may be placed between one ink droplet Dtb and the other ink droplet Dtb discharged onto the inclined surface KM1. [Explanation of symbols]

[0086] 1a Droplet discharge device 3 carriages 5 Display section 5r review screen 6 Platen 10 Discharge heads 20 Control device 58 3D cameras 121 Nozzles 128 Pressure Chamber 160 Actuators D1 1st direction D2 2nd direction Df Conveying direction Ds moving direction H1 Distance between the discharge surface and the parallel surface H2 Distance between the discharge surface and the inclined surface HM parallel plane KM1,KM2,KM11,KM12,KM21,KM22 Inclined surface NM discharge surface P11, P12 Pitch in the first direction P2 Pitch in the second direction Pd discharge pulse W Printing medium WM discharged surface Wp1, Wp2 drive waveforms α1 1st angle α2 2nd angle

Claims

1. A dispensing head that dispenses droplets onto a printing medium having a surface to be dispensed that includes a parallel surface parallel to the dispensing surface and an inclined surface inclined with respect to the dispensing surface, based on image data, A distance detection device for detecting the distance between the discharge surface and the parallel surface, and the distance between the discharge surface and the inclined surface, A control device is provided, The control device, when the surface from which the droplets should be ejected is the inclined surface, obtains information regarding a printing mode selected by the user from among a plurality of printing modes for controlling the ejection of the droplets to the inclined surface, based on the detection result by the distance detection device, and performs droplet ejection control to the inclined surface based on the printing mode selected by the user.

2. The aforementioned multiple print modes are: A first printing mode in which the pitch of adjacent droplets on the inclined surface in a first direction parallel to the parallel surface is the same as the pitch of adjacent droplets on the parallel surface in the first direction, and The droplet ejection apparatus according to claim 1, comprising a second printing mode in which the pitch of adjacent droplets on the inclined surface in a second direction parallel to the inclined surface is the same as the pitch of adjacent droplets on the parallel surface in the first direction.

3. The droplet ejection apparatus according to claim 2, wherein the control device controls the operation of the ejection head to change the print resolution of the inclined surface in a direction perpendicular to the ejection surface according to the angle that the inclined surface makes with the ejection surface in the second printing mode.

4. The inclined surface includes a first inclined surface having a first angle with respect to the discharge surface, and a second inclined surface having a second angle with respect to the discharge surface that is greater than the first angle. The droplet ejection device according to claim 3, wherein the control device controls the operation of the ejection head in the second printing mode such that the printing resolution of the second inclined surface is higher than the printing resolution of the first inclined surface.

5. The aforementioned discharge head is mounted on a carriage that moves in the direction of movement, The discharge head includes a nozzle for discharging droplets onto the printing medium and an actuator for applying pressure to the liquid in a pressure chamber connected to the nozzle. The droplet ejection apparatus according to claim 4, wherein, in the second printing mode, when the printing resolution of the second inclined surface is made higher than that of the first inclined surface, the control device reduces the movement speed of the carriage compared to when printing on the first inclined surface, or increases the number of ejection pulses in one drive cycle of the drive waveform that drives the actuator compared to when printing on the first inclined surface.

6. The droplet ejection device according to claim 1, wherein the plurality of printing modes include a third printing mode in which the operation of the ejection head is controlled such that the volume of droplets to be ejected onto the inclined surface is greater than the volume of droplets to be ejected onto the parallel surface.

7. The droplet ejection device according to claim 6, wherein the control device controls the operation of the ejection head in the third printing mode, in place of or in conjunction with the process of ejecting droplets with a volume larger than the volume of droplets to be ejected on the parallel surface onto the inclined surface, such that the number of droplets per unit area to be ejected on the inclined surface is greater than the number of droplets per unit area to be ejected on the parallel surface.

8. The droplet ejection device according to claim 6, wherein the control device controls the operation of the ejection head in the third printing mode such that the volume of the droplets to be ejected onto the inclined surface or the number of droplets changes according to the angle that the inclined surface makes with the ejection surface.

9. The inclined surface includes a first inclined surface having a first angle with respect to the discharge surface, and a second inclined surface having a second angle with respect to the discharge surface that is greater than the first angle. The droplet ejection device according to claim 8, wherein the control device controls the operation of the ejection head in the third printing mode such that the volume of droplets to be ejected onto the second inclined surface is greater than the volume of droplets to be ejected onto the first inclined surface, or the number of droplets to be ejected onto the second inclined surface is greater than the number of droplets to be ejected onto the first inclined surface.

10. The system further comprises a carriage on which the discharge head is mounted and which moves in the direction of movement, and a transport unit that transports the printing medium in the transport direction, The inclined surface and the parallel surface of the printing medium are provided along the transport direction. The droplet dispensing apparatus according to claim 1, wherein the control device controls the movement of the carriage and the movement of the dispensing head so as to print multiple passes on the inclined surface.

11. The droplet dispensing apparatus according to claim 10, wherein the control device controls the operation of the carriage and the operation of the dispensing head such that the number of pass printings on the inclined surface is greater than the number of pass printings on the parallel surface.

12. The droplet dispensing apparatus according to claim 1, wherein the control device outputs image data of a review screen showing the printing pattern on the printing medium after the user has selected one of the plurality of printing modes.

13. The aforementioned discharge head is mounted on a carriage that moves in the direction of movement, The droplet dispensing apparatus according to claim 12, wherein the control device outputs the image data after detecting the distance using the distance detection device while moving the carriage in the direction of movement.

14. The droplet ejection apparatus according to claim 12, wherein the control device acquires resolution input information in which the user arbitrarily inputs the printing resolution of the inclined surface in a direction perpendicular to the ejection surface.

15. The aforementioned discharge head is mounted on a carriage that moves in the direction of movement, The droplet ejection device according to claim 1, wherein the control device determines an upper limit of the angle between the inclined surface and the ejection surface when controlling the ejection of droplets to the inclined surface, based on the ratio of the print resolution required for the parallel surface based on the image data and the maximum print resolution on the parallel surface determined based on the movement resolution of the carriage.

Images