Printing apparatus
The printing apparatus addresses thermal degradation in light irradiation units by adjusting light source activation based on distance, enhancing lifespan and energy efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- BROTHER KOGYO KK
- Filing Date
- 2022-05-27
- Publication Date
- 2026-06-02
Smart Images
Figure 0007868408000001 
Figure 0007868408000002 
Figure 0007868408000003
Abstract
Description
Technical Field
[0001] The present invention relates to a printing apparatus.
Background Art
[0002] Conventionally, as a printing apparatus, for example, a liquid ejection apparatus disclosed in Patent Document 1 is known. This liquid ejection apparatus includes a liquid ejection unit that ejects a photocurable liquid onto a medium, and a light irradiation unit that irradiates the liquid ejected onto the medium with light from a light source to cure the liquid.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the liquid ejection apparatus of Patent Document 1 described above, when the distance between the light irradiation unit and the medium is a first distance, the light intensity from the light irradiation unit is increased as compared with the case where the distance is a second distance smaller than the first distance. Thus, at the first distance, the light intensity is increased to cure the liquid, but the light source generates heat and is likely to deteriorate thermally. As a result, if some of the plurality of light sources in the light irradiation unit deteriorate thermally, there is a risk that the light irradiation unit must be replaced.
[0005] In view of such a situation, an object of the present invention is to provide a printing apparatus capable of extending the life of a light irradiation unit.
Means for Solving the Problems
[0006] A printing apparatus according to one aspect of the present invention comprises a head having a plurality of nozzles for ejecting photocurable ink onto a printing medium, a light irradiation unit having a plurality of light source rows for irradiating the ink on the printing medium with light, a moving device for moving the head and the light irradiation unit in a first direction, and a control unit, wherein each of the plurality of light source rows consists of a plurality of light sources arranged in a row along a second direction intersecting the first direction, and the plurality of light source rows are arranged in the first direction and provided at both ends of the first direction, and at least one light source row provided in the center between the one-end light source row and the other-end light source row Each unit has one central light source array, and the control unit performs a first acquisition operation to acquire the distance between the light irradiation unit and the printing medium, an ejection operation to eject ink from the head onto the printing medium, and an irradiation operation to irradiate light onto the ink on the printing medium from the light irradiation unit. In the irradiation operation, if the distance is a first predetermined distance, the one-end light source array, the other-end light source array and the central light source array are turned on, and if the distance is a second predetermined distance which is smaller than the first predetermined distance, the one-end light source array and the other-end light source array are turned on, and at least one of the central light source arrays is turned off. [Effects of the Invention]
[0007] The present invention has the effect of providing a printing apparatus that can extend the lifespan of the light irradiation section.
[0008] The above-mentioned objectives, other objectives, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings. [Brief explanation of the drawing]
[0009] [Figure 1] This is a perspective view of the printing apparatus according to all embodiments. [Figure 2] Figure 1 is a functional block diagram showing the configuration of the printing apparatus. [Figure 3] This is a schematic diagram of a head unit with an odd number of light source rows, viewed from below. [Figure 4]This flowchart shows an example of a control method for a printing apparatus according to Embodiments 1 to 3. [Figure 5] This is a schematic diagram of a head unit with an even number of light source rows, viewed from below. [Figure 6] This flowchart shows an example of a control method for a printing apparatus according to Embodiment 4. [Modes for carrying out the invention]
[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference numerals throughout all the drawings.
[0011] (Embodiment 1) <Printing device> The printing apparatus 10 according to Embodiment 1 of the present invention, as shown in Figure 1, is an inkjet printer that, for example, ejects ink from a head 20 toward a printing medium A, and irradiates light from a light irradiation unit 30 onto the ink on the printing medium A to print an image on the printing medium A using the ink. Note that the printing apparatus 10 is not limited to an inkjet printer. The printing medium A is, for example, fabric and paper having a sheet shape, or a ball and a mug having a three-dimensional shape. The ink is a photocurable ink that hardens when irradiated with light.
[0012] The printing apparatus 10 includes a head unit 11 containing a head 20 and a light irradiation unit 30, a moving device 40, a transport device 50, and a control unit 60 (Figure 2). Details of the control unit 60 will be described later. The first direction in which the moving device 40 moves the head 20 and the light irradiation unit 30 is referred to as the left-right direction. The second direction intersecting (for example, perpendicular to) the first direction is referred to as the front-back direction. Furthermore, the direction intersecting (for example, perpendicular to) both the first and second directions is referred to as the up-down direction. However, the arrangement of the printing apparatus 10 is not limited to these.
[0013] The moving device 40 has a pair of moving rails 41, a carriage 42, a drive belt 43, and a moving motor 44, and moves the head unit 11 in the left-right direction. The pair of moving rails 41 are elongated members extending in the left-right direction and are arranged parallel to each other in the front-rear direction so as to sandwich the head unit 11 between them. The carriage 42 mounts the head unit 11 and is supported by the moving rails 41 so as to be movable in the left-right direction along the moving rails 41. The drive belt 43 is an endless belt. The drive belt 43 extends along the moving rails 41 in the left-right direction, is connected to the carriage 42, and is connected to the moving motor 44 via a pulley. When the moving motor 44 drives the drive belt 43, the carriage 42 reciprocates in the left-right direction along the moving rails 41. As a result, the moving device 40 moves the printing medium A and the head unit 11 relative to each other in the left-right direction.
[0014] The transport device 50 includes a platen 51, a transport rail 52, a platen support base 53, and a transport motor 54 (Figure 2). The upper surface of the platen 51 faces the discharge surface 20a (Figure 3), which is the lower surface of the head 20, and the lower surface of the light irradiation unit 30. The platen 51 supports the printing medium A, which is placed on its upper surface. The platen 51 defines the distance between the printing medium A and the head 20 and light irradiation unit 30 in the vertical direction. The transport rail 52 extends in the front-rear direction. The platen support base 53 supports the platen 51, for example. The platen support base 53 is supported so as to be movable in the front-rear direction along the transport rail 52. The platen support base 53 is connected to the transport motor 54. The transport motor 54 drives the platen support base 53, moving the platen 51 in the front-rear direction. As a result, the transport device 50 transports the printing medium A forward, for example.
[0015] <Head Unit> As shown in FIG. 3, the head unit 11 has a head 20 and a light irradiation unit 30. The head 20 has a plurality of nozzles 21, ink flow paths 22, a flow path forming body 23, and a plurality of drive elements 24 (FIG. 2). The plurality of nozzles 21 are arranged at intervals along the front-rear direction to form a nozzle row. The plurality of nozzle rows are arranged at intervals in the left-right direction.
[0016] The flow path forming body 23 has, for example, a rectangular parallelepiped shape, and the nozzles 21 and the ink flow paths 22 are formed inside thereof. The nozzles 21 open to the discharge surface 20a of the flow path forming body 23. The ink flow paths 22 are connected to the tank 12 (FIG. 1) and the nozzles 21. The ink flow paths 22 have a common flow path 25 and a plurality of individual flow paths 26 between the tank 12 (FIG. 1) and the nozzles 21. The common flow path 25 communicates with the tank 12. The common flow path 25 extends in the front-rear direction in the flow path forming body 23 and is connected to the plurality of individual flow paths 26. The individual flow paths 26 are connected to the common flow path 25 and the nozzles 21. Therefore, the ink flows from the tank 12 into the common flow path 25, is branched into the individual flow paths 26 while flowing in the front-rear direction in the common flow path 25, and is supplied from the individual flow paths 26 to the nozzles 21.
[0017] The drive element 24 is a piezoelectric element or the like, is provided corresponding to the individual flow paths 26, and drives to vary the volume of the individual flow paths 26. By driving the drive element 24, pressure for discharging the ink from the nozzles 21 is applied to the ink in the individual flow paths 26, and the ink is discharged from the nozzles 21 and lands on the printing medium A. Note that the drive element 24 is not limited to a piezoelectric element, and for example, a thermal actuator such as a heating resistor that generates bubbles, and an electrostatic actuator such as an electrode that generates an electrostatic force may be used.
[0018] The light irradiation unit 30 is disposed upstream of the head 20 in the direction in which the head 20 moves while discharging ink. For example, the head 20 discharges ink when moving to the left and does not discharge ink when moving to the right. In this case, the light irradiation unit 30 is disposed on the right, which is upstream of the head 20 in the leftward moving direction during ink discharge. Thereby, while moving following the head 20 that discharges ink onto the print medium A, the light irradiation unit 30 irradiates light on the ink on the print medium A.
[0019] The light irradiation unit 30 has a plurality of light sources 31 and a circuit board 32 on which the light sources 31 are mounted. The circuit board 32 has, for example, a board made of an insulating material and conductor wirings disposed on the lower surface thereof, and the light sources 31 are connected to the wirings. The light source 31 is a light-emitting element such as an LED, for example, and is driven by the control unit 60 to emit light (for example, ultraviolet light or infrared light) that cures the ink discharged from the nozzle 21. The plurality of light sources 31 are arranged at intervals along the front-rear direction to form a light source row 33.
[0020] The plurality of light source rows 33 are arranged at intervals in the left-right direction. In the example of FIG. 3, the first light source row 331, the second light source row 332, the third light source row 333, the fourth light source row 334, and the fifth light source row 335 are arranged in this order from the left. The first light source row 331 is an end light source row 33a provided at the left end, which is one end in the left-right direction, of the plurality of light source rows 33. The first light source row 331 has no adjacent light source row 33 on the left in the left-right direction and is adjacent to the second light source row 332 on the right. The fifth light source row 335 is an end light source row 33b provided at the right end, which is the other end in the left-right direction, of the plurality of light source rows 33. The fifth light source row 335 has no adjacent light source row 33 on the right in the left-right direction and is adjacent to the fourth light source row 334 on the left. The third light source row 333 is a central light source row 33c provided at the center between the first light source row 331 and the fifth light source row 335 in the left-right direction and is arranged at the center in the left-right direction among the plurality of light source rows 33. The number of light source rows 33 to the right of the third light source row 333 and the number of light source rows 33 to the left of the third light source row 333 among the plurality of light source rows 33 are equal to each other.
[0021] <Department Head> As shown in Figure 2, the control unit 60 is a computer that controls each part of the printing device 10, and has an interface 61, an arithmetic unit 62, and a storage unit 63. The interface 61 receives various data such as image data from external devices B such as a computer, camera, communication network, recording medium, display, and printer. Image data is data that represents an image to be printed on the printing medium A, such as raster data. The control unit 60 may be composed of a single device, or multiple devices may be distributed and configured to cooperate in the operation of the control unit 60.
[0022] The memory unit 63 is a memory accessible by the arithmetic unit 62 and is composed of RAM and ROM, etc. The RAM temporarily stores various types of data such as image data. The ROM stores programs and predetermined data for performing various data processing.
[0023] The arithmetic unit 62 is composed of a processor such as a CPU. The arithmetic unit 62 executes a program stored in ROM, and the control unit 60 controls the drive element 24, light source 31, moving motor 44 and transport motor 54 to perform the process of printing an image onto the printing medium A.
[0024] Furthermore, the control unit 60 may be electrically connected to the input device 13. The input device 13 may be, for example, a button and a mouse, which are operated by the user to input information to the control unit 60. The input device 13 may also be a touch panel integrated with the display device. Alternatively, the input device 13 may be an interface 61 to which information is input from an external source.
[0025] The control unit 60 is connected to the drive element 24 of the head 20 via the head drive circuit 64 and controls the drive of the drive element 24. This controls the timing and amount of ink ejection from the head 20 by the drive element 24. The control unit 60 is also connected to the light source 31 of the light irradiation unit 30 via the light irradiation drive circuit 65 and controls the drive of the light source 31. This controls the turning on and off of the light source 31.
[0026] The control unit 60 is connected to the mobile motor 44 of the mobile device 40 via the mobile drive circuit 66 and controls the drive of the mobile motor 44. This controls the movement of the head 20 and the light irradiation unit 30 by the mobile device 40. The control unit 60 is connected to the transport motor 54 of the transport device 50 via the transport drive circuit 67 and controls the drive of the transport motor 54. This controls the transport of the printing medium A by the transport device 50.
[0027] <Control method for printing devices> The control method for the printing device 10 is performed by the control unit 60 according to the flowchart in Figure 4, for example. Here, when the control unit 60 acquires image data (step S1: YES), it performs a first acquisition operation to acquire the irradiation interval, which is the distance between the light irradiation unit 30 and the printing medium A (step S2). This irradiation interval is the distance between the light irradiation unit 30 and the printing medium A in the vertical direction, and is acquired by the control unit 60 based on, for example, the shape information of the printing medium A.
[0028] The shape information of the printing medium A includes the height between the bottom and top surfaces of the printing medium A along the vertical direction, and may be input to the control unit 60 from, for example, an external device B or an input device 13. The control unit 60 obtains the vertical positions of the platen 51 and the light irradiation unit 30 from a storage unit 63 or the like. Then, the control unit 60 obtains the irradiation interval between the printing medium A placed on the platen 51 and the light irradiation unit 30 from the positions of the platen 51 and the light irradiation unit 30, and the height of the printing medium A. If the printing device 10 is equipped with a sensor, the sensor may measure the distance to the top surface of the printing medium A. In this case, the control unit 60 may obtain the irradiation interval between the light irradiation unit 30 and the printing medium A based on the distance measured by the sensor and the position of the light irradiation unit 30.
[0029] Next, the control unit 60 performs a printing operation to print an image onto the printing medium A using ink (step S3). In this printing operation, the control unit 60 alternately performs pass processing and transport processing. In pass processing, the control unit 60 performs a movement operation to move the head 20 and the light irradiation unit 30 in the left-right direction, as well as an ejection operation to eject ink from the head 20 onto the printing medium A, and an irradiation operation to irradiate light onto the ink on the printing medium A from the light irradiation unit 30.
[0030] In this pass process, the print head 20 moves to the left, ejecting ink from the nozzles 21 of the print head 20, causing the ink to land on the printing medium A. Then, the light irradiation unit 30 moves to the left, irradiating the ink on the printing medium A with light from the light irradiation unit 30. This irradiated light hardens the ink and fixes it to the printing medium A, and the image created by the ink is printed on the printing medium A.
[0031] In this irradiation operation, the larger the irradiation interval between the printing medium A and the light irradiation unit 30, the greater the illuminance (mW / cm²) of light irradiated per unit area of the printing medium A per unit time from the light irradiation unit 30. 2The ) becomes smaller. For this reason, when the irradiation interval is a first predetermined interval, the control unit 60 lights up the one-end light source array 33a, the other-end light source array 33b, and the central light source array 33c. Also, when the irradiation interval is a second predetermined interval which is smaller than the first predetermined interval, the control unit 60 lights up the one-end light source array 33a and the other-end light source array 33b, and turns off at least one central light source array 33c.
[0032] In the example shown in Figure 3, when the irradiation interval is large compared to the first predetermined interval, the control unit 60 lights up all the light sources 31 of the first to fifth light source rows 331 to 335 in the light irradiation unit 30. As a result, the control unit 60 lights up all the light sources 31 of the first light source row 331, which is the light source row 33a at one end, all the light sources 31 of the fifth light source row 335, which is the light source row 33b at the other end, and all the light sources 31 of the third light source row 333, which is the central light source row 33c.
[0033] Thus, when the irradiation interval is the first predetermined interval, the number of light sources 31 that are lit is greater than when the irradiation interval is the second predetermined interval. Therefore, because the intensity of the light emitted from the light irradiation unit 30 is greater at the first predetermined interval than at the second predetermined interval, even when the irradiation interval is long, the illuminance of the light irradiated onto the printing medium A is not too low, and the ink on the printing medium A can be cured by the light.
[0034] On the other hand, when the irradiation interval is small, as is the second predetermined interval, the control unit 60 turns off all the light sources 31 of the third light source row 333 and turns on all the light sources 31 of the light source rows 33 other than the third light source row 333. As a result, the control unit 60 turns on all the light sources 31 of the first light source row 331, which is the light source row 33a at one end, and all the light sources 31 of the fifth light source row 335, which is the light source row 33b at the other end, and turns off all the light sources 31 of the third light source row 333, which is the central light source row 33c.
[0035] In this way, by turning off the central light source row 33c, thermal degradation due to the light emission of the light source 31 of the central light source row 33c can be reduced. Furthermore, due to the heat distribution in the light irradiation section 30, where the temperature is higher towards the center, the central light source row 33c is more susceptible to thermal degradation than the light source row 33a at one end and the light source row 33b at the other end. In contrast, by turning off the central light source row 33c, the temperature in the center of the light irradiation section 30 can be reduced, thereby reducing the thermal degradation of the light source 31 of the central light source row 33c. As a result, replacement of the light irradiation section 30 can be suppressed, and the lifespan of the light irradiation section 30 can be extended.
[0036] Furthermore, when the irradiation interval is the second predetermined interval, the number of light sources 31 that are lit is smaller than when the irradiation interval is the first predetermined interval. Therefore, energy saving in the light irradiation unit 30 can be achieved. In addition, because the intensity of the light emitted from the light irradiation unit 30 is suppressed in the case of the second predetermined interval compared to the case of the first predetermined interval, even with a short irradiation interval, the illuminance of the light irradiated onto the printing medium A is not too high, and thermal degradation of the printing medium A due to light can be reduced.
[0037] Furthermore, when the irradiation interval is the second predetermined interval, the light sources 31 of the first light source row 331, the second light source row 332, the fourth light source row 334, and the fifth light source row 335 are lit. As a result, the integrated amount of light (mJ / cm²) irradiated from the light irradiation unit 30 onto the printing medium A is increased. 2 The total light intensity is greater than or equal to the cumulative light intensity required to cure the ink on the printing medium A. Therefore, even if some of the light sources 31 of the light source array 33 in the light irradiation unit 30 are turned off, the ink on the printing medium A can still be cured. Furthermore, if the ink on the printing medium A can be cured, the light sources 31 of at least one of the light source arrays 33 of the second light source array 332 and the fourth light source array 334 may be turned off.
[0038] Next, the control unit 60 transports the printing medium A forward during the transport process. As a result, the image formed by the previous pass processing performed before this transport process moves forward. Then, the current pass processing performed after this transport process forms an image behind the image formed by the previous pass processing. In this way, the pass processing and transport processing are repeated in the printing operation of step S3 until the entire image based on the image data is printed (step S4: NO), so that the image formed by the pass processing is sequentially printed on the printing medium A. When the entire image based on the image data is printed, printing is completed (step S4: YES).
[0039] In the example shown in Figure 3, since the number of light source rows 33 in the light irradiation unit 30 was odd, the single third light source row 333 located in the center of the multiple light source rows 33 was designated as the central light source row 33c. In contrast, if the number of light source rows 33 in the light irradiation unit 30 is even, the two light source rows 33 located in the center of the multiple light source rows 33 are designated as the central light source row 33c.
[0040] For example, in the case of Figure 5, the light irradiation unit 30 has the first light source array 331, the second light source array 332, the third light source array 333, the fourth light source array 334, the fifth light source array 335, and the sixth light source array 336 arranged from left to right in this order. In this case, of the first to sixth light source arrays 331 to 336, the third and fourth light source arrays 333 and 334, which are located in the center, are the central light source array 33c. Of the first to sixth light source arrays 331 to 336, the number of light source arrays 33 located to the left of the third and fourth light source arrays 333 and 334 is equal to the number of light source arrays 33 located to the right of the third and fourth light source arrays 334. Also, the first light source array 331 is the one-end light source array 33a, and the sixth light source array 336 is the other-end light source array 33b.
[0041] In the irradiation operation shown in the example in Figure 5, the control unit 60 lights up the first light source row 331, which is the light source row 33a at one end, the sixth light source row 336, which is the light source row 33b at the other end, and the third and fourth light source rows 333 and 334, which are the central light source rows 33c, when the irradiation interval is a first predetermined interval. For example, the control unit 60 lights up the first to sixth light source rows 331 to 336. Furthermore, when the irradiation interval is a second predetermined interval which is shorter than the first predetermined interval, the control unit 60 lights up the light source row 33a at one end and the light source row 33b at the other end, and turns off at least one central light source row 33c. For example, the control unit 60 turns off at least one of the light source rows 33, from the third to sixth light source rows 333 and 434, and lights up the remaining light source rows 33. This makes it possible to extend the lifespan of the light irradiation unit 30.
[0042] (Embodiment 2) The printing apparatus 10 according to Embodiment 2 of the present invention, as shown in the example in Figures 1 and 2, comprises a head 20 having a plurality of nozzles 21 for ejecting photocurable ink onto a printing medium A, a light irradiation unit 30 having a plurality of light source rows 33 for irradiating light onto the ink on the printing medium A, a moving device 40 for moving the head 20 and the light irradiation unit 30 in a first direction, a transport device 50 for transporting the printing medium A in a second direction intersecting the first direction, and a control unit 60. Each of the plurality of light source rows 33 is composed of a plurality of light sources 31 arranged in a row along the second direction. The plurality of light source rows 33 are arranged in the first direction and have one-end light source rows 33a and the other-end light source rows 33b provided at both ends of the first direction, and a plurality of intermediate light source rows 33d provided between the one-end light source rows 33a and the other-end light source rows 33b. The control unit 60 performs a first acquisition operation to acquire the distance between the light irradiation unit 30 and the printing medium A, and a printing operation to print an image on the printing medium A using ink. In the printing operation, the control unit 60 alternately performs a pass process in which the head 20 and the light irradiation unit 30 are moved in a first direction, ink is ejected from the head 20 onto the printing medium A, and light is irradiated onto the ink on the printing medium A from the light irradiation unit 30, and a transport process in which the printing medium A is transported in a second direction. In the pass process, if the interval is a first predetermined interval, the control unit 60 lights up one end light source array 33a, the other end light source array 33b, and a plurality of intermediate light source arrays 33d. If the interval is a second predetermined interval which is smaller than the first predetermined interval, the control unit 60 lights up one end light source array 33a and the other end light source array 33b, and lights up some of the plurality of intermediate light source arrays 33d in a change with each pass process, while turning off the other intermediate light source arrays 33d.
[0043] Specifically, in the example shown in Figure 3, the light irradiation unit 30 has the first light source array 331, the second light source array 332, the third light source array 333, the fourth light source array 334, and the fifth light source array 335 arranged from left to right in this order. In this case, the first light source array 331 is the one-end light source array 33a, and the fifth light source array 335 is the other-end light source array 33b. Furthermore, the second light source array 332, the third light source array 333, and the fourth light source array 334, which are all light source arrays 33 located between the first light source array 331 and the fifth light source array 335, constitute the intermediate light source array 33d. In the light irradiation unit 30, the light source array 33 to the left of the intermediate light source array 33d is the one-end light source array 33a, and the light source array 33 to the right of the intermediate light source array 33d is the other-end light source array 33b. The intermediate light source array 33d includes the central light source array 33c.
[0044] The control method for this printing device 10 is performed by the control unit 60 according to the flowchart in Figure 4, for example. Here, when the control unit 60 acquires image data (step S1: YES), it performs a first acquisition operation (step S2), and then performs a printing operation (step S3). In this printing operation, the control unit 60 alternately performs pass processing and transport processing. In pass processing, the control unit 60 performs a movement operation to move the head 20 and the light irradiation unit 30 in the left and right directions, as well as an ejection operation to eject ink from the head 20 onto the printing medium A, and an irradiation operation to irradiate the ink on the printing medium A with light from the light irradiation unit 30.
[0045] In this irradiation operation, the control unit 60 controls the blinking of the light sources 31 for each light source row 33 and for each pass, according to the irradiation interval between the light irradiation unit 30 and the printing medium A. In the example in Figure 3, if the irradiation interval acquired in the first acquisition operation is large compared to the first predetermined interval, the control unit 60 lights up the light sources 31 of all light source rows 33 from the first light source row 331 to the fifth light source row 335 in the light irradiation unit 30. As a result, many light sources 31 are lit, causing the ink on the printing medium A to harden.
[0046] On the other hand, if the irradiation interval is smaller than the second predetermined interval and the first predetermined interval, the control unit 60 lights up all the light sources 31 of the first light source row 331, which is the light source row 33a at one end, and all the light sources 31 of the fifth light source row 335, which is the light source row 33b at the other end, among all the light source rows 33 in the light irradiation unit 30. In addition, the control unit 60 lights up all the light sources 31 of some of the light source rows 33 of the second to fourth light source rows 334, which are the intermediate light source rows 33d, and turns off all the light sources 31 of the other light source rows 33. The control unit 60 changes which intermediate light source rows 33d are lit up for each pass processing.
[0047] For example, in the first pass processing, all the light sources 31 of the second light source row 332 in the intermediate light source row 33d are turned on, and all the light sources 31 of the third light source row 333 and the fourth light source row 334 are turned off. As a result, in the first pass processing, all the light sources 31 of the first light source row 331, the second light source row 332 and the fifth light source row 335 are turned on, and the light irradiation unit 30 irradiates light onto the ink on the printing medium A. Subsequently, in the second pass processing immediately following the first pass processing, all the light sources 31 of the third light source row 333 in the intermediate light source row 33d are turned on, and all the light sources 31 of the second light source row 332 and the fourth light source row 334 are turned off. As a result, in the second pass processing, all the light sources 31 of the first light source row 331, the third light source row 333 and the fifth light source row 335 are turned on, and the light irradiation unit 30 irradiates light onto the ink on the printing medium A. Next, in the third pass processing immediately following the second pass processing, all light sources 31 of the fourth light source row 334 in the intermediate light source row 33d are turned on, and all light sources 31 of the second light source row 332 and the third light source row 333 are turned off. As a result, in the third pass processing, all light sources 31 of the first light source row 331, the fourth light source row 334, and the fifth light source row 335 are turned on, and the light irradiation unit 30 irradiates light onto the ink on the printing medium A.
[0048] In this way, by sequentially turning off some of the light source rows 33 in the intermediate light source row 33d, thermal degradation due to the light emission of the light sources 31 themselves in the intermediate light source row 33d can be reduced. Furthermore, due to the heat distribution in the light irradiation section 30, where the temperature is higher towards the center, the intermediate light source row 33d is more susceptible to thermal degradation than the light source row 33a at one end and the light source row 33b at the other end. In contrast, by sequentially turning off the lights in the intermediate light source row 33d, the temperature in the center of the light irradiation section 30 can be reduced, thereby reducing the thermal degradation of the light sources 31 in the intermediate light source row 33d. As a result, replacement of the light irradiation section 30 can be suppressed, and the lifespan of the light irradiation section 30 can be extended.
[0049] Furthermore, when the irradiation interval is set to the second predetermined interval, fewer light sources 31 are lit than when the irradiation interval is set to the first predetermined interval, thus saving energy in the light irradiation unit 30. In addition, when the irradiation interval is set to the second predetermined interval, the intensity of light emitted from the light irradiation unit 30 is lower than when the irradiation interval is set to the first predetermined interval, thus reducing the thermal degradation of the printing medium A due to light.
[0050] In the example described above, when the irradiation interval was the second predetermined interval, the control unit 60 turned on one of the intermediate light source arrays 33d in the light irradiation unit 30 and turned off the other light source arrays 33. However, the number of light source arrays 33 to be turned on is not limited to one, as long as they are part of the intermediate light source arrays 33d. For example, the control unit 60 may turn on two or more light source arrays 33 of the intermediate light source arrays 33d and turn off the other light source arrays 33.
[0051] Furthermore, in the above example, when the irradiation interval was the second predetermined interval, the control unit 60 changed the order in which the intermediate light source array 33d was lit for each pass. However, the lighting order of the intermediate light source array 33d is not limited to this. For example, the control unit 60 may change the number of times the central light source array 33c, which is prone to thermal degradation due to heat distribution, is lit for each pass, so that it is fewer than the number of times the other light source arrays 33 are lit.
[0052] (Embodiment 3) The printing apparatus 10 according to Embodiment 3 of the present invention, as shown in the example in Figures 1 and 2, includes a head 20 having a plurality of nozzles 21 for ejecting photocurable ink onto a printing medium A, a light irradiation unit 30 having a plurality of light source rows 33 for irradiating light onto the ink on the printing medium A, a moving device 40 for moving the head 20 and the light irradiation unit 30 in a first direction, a transport device 50 for transporting the printing medium A in a second direction intersecting the first direction, and a control unit 60. Each of the plurality of light source rows 33 is composed of a plurality of light sources 31 arranged in a row along the second direction, and the plurality of light source rows 33 are arranged in the first direction. The control unit 60 performs a first acquisition operation to acquire the distance between the light irradiation unit 30 and the printing medium A, and a printing operation to print an image on the printing medium A using ink. In the printing operation, the control unit 60 alternately performs a pass process in which the head 20 and the light irradiation unit 30 are moved in a first direction, ink is ejected from the head 20 onto the printing medium A, and light is irradiated onto the ink on the printing medium A from the light irradiation unit 30, and a transport process in which the printing medium A is transported in a second direction. In the pass process, if the interval is a second predetermined interval which is smaller than the first predetermined interval, the control unit 60 reduces the number of light source rows 33 that are lit among the multiple light source rows 33, and changes the light source rows 33 that are lit for each pass process.
[0053] The control method for this printing device 10 is performed by the control unit 60 according to the flowchart in Figure 4, for example. Here, when the control unit 60 acquires image data (step S1: YES), it performs a first acquisition operation (step S2), and then performs a printing operation (step S3). In this printing operation, the control unit 60 alternately performs pass processing and transport processing. In pass processing, the control unit 60 performs a movement operation to move the head 20 and the light irradiation unit 30 in the left and right directions, as well as an ejection operation to eject ink from the head 20 onto the printing medium A, and an irradiation operation to irradiate the ink on the printing medium A with light from the light irradiation unit 30.
[0054] In this irradiation operation, the control unit 60 controls the blinking of the light sources 31 for each light source row 33 and for each pass, according to the irradiation interval between the light irradiation unit 30 and the printing medium A. In the example in Figure 5, when the irradiation interval is large, equal to the first predetermined interval, the control unit 60 lights up the light sources 31 of all light source rows 33 from the first light source row 331 to the sixth light source row 336 in the light irradiation unit 30. As a result, many light sources 31 are lit, causing the ink on the printing medium A to harden.
[0055] On the other hand, if the irradiation interval is shorter than the second predetermined interval and the first predetermined interval, the control unit 60 lights up all the light sources 31 of some of the light source rows 33 in the light irradiation unit 30, and turns off all the light sources 31 of the other light source rows 33. The control unit 60 changes which light source row 33 to light up for each pass processing.
[0056] For example, in the first pass processing, all light sources 31 of the first light source array 331 and the second light source array 332 are turned on, and all light sources 31 of the third light source array 333 to the sixth light source array 336 are turned off, and the light irradiation unit 30 irradiates light onto the ink on the printing medium A. Subsequently, in the second pass processing immediately following the first pass processing, all light sources 31 of the third light source array 333 and the fourth light source array 334 are turned on, and all light sources 31 of the first light source array 331, the second light source array 332, the fifth light source array 335 and the sixth light source array 336 are turned off, and the light irradiation unit 30 irradiates light onto the ink on the printing medium A. Subsequently, in the third pass processing immediately following the second pass processing, all light sources 31 of the fifth light source array 335 and the sixth light source array 336 are turned on, and all light sources 31 of the first light source array 331 to the fourth light source array 334 are turned off, and the light irradiation unit 30 irradiates light onto the ink on the printing medium A.
[0057] In this way, by sequentially turning off some of the light source rows 33 in the light irradiation unit 30, thermal degradation due to the light emission of the light sources 31 themselves in those light source rows 33 can be reduced. Also, due to the heat distribution in the light irradiation unit 30, where the temperature is higher towards the center, light source rows 33 closer to the center are more susceptible to thermal degradation. In contrast, by sequentially turning off the light source rows 33, the temperature in the center of the light irradiation unit 30 can be reduced. As a result, the replacement of the light irradiation unit 30 can be suppressed and its lifespan can be extended.
[0058] Furthermore, when the irradiation interval is set to the second predetermined interval, fewer light sources 31 are lit than when the irradiation interval is set to the first predetermined interval, thus saving energy in the light irradiation unit 30. In addition, when the irradiation interval is set to the second predetermined interval, the intensity of light emitted from the light irradiation unit 30 is lower than when the irradiation interval is set to the first predetermined interval, thus reducing the thermal degradation of the printing medium A due to light.
[0059] In the example described above, when the irradiation interval was the second predetermined interval, the control unit 60 turned on two of the light source arrays 33 in the light irradiation unit 30 and turned off the other light source arrays 33. However, the number of light source arrays 33 to be turned on is not limited to two, but may be one or three or more, as long as they are some of the multiple light source arrays 33 in the light irradiation unit 30.
[0060] Furthermore, in the above example, when the irradiation interval was the second predetermined interval, the control unit 60 lit up two light source rows 33 in the light irradiation unit 30 that were adjacent to each other in the left-right direction. However, the arrangement of the light source rows 33 to be lit is not limited to adjacent light source rows 33, as long as they are some of the multiple light source rows 33 in the light irradiation unit 30. For example, a light source row 33 to be turned off may be sandwiched between the two light source rows 33 to be lit.
[0061] Furthermore, in the above example, when the irradiation interval was the second predetermined interval, the control unit 60 changed the order in which the light source arrays 33 were lit for each pass. However, the lighting order of the light source arrays 33 is not limited to this. For example, the control unit 60 may change the lighting order of the light source arrays 33, which are closer to the center and more susceptible to thermal degradation due to heat distribution, for each pass so that the number of times they are lit is less than the number of times the other light source arrays 33 are lit.
[0062] (Embodiment 4) As shown in Figures 1 and 2, the printing apparatus 10 according to Embodiment 4 of the present invention includes a head 20 having a plurality of nozzles 21 for ejecting photocurable ink onto a printing medium A, a light irradiation unit 30 having a plurality of light source rows 33 for irradiating light onto the ink on the printing medium A, a moving device 40 for moving the head 20 and the light irradiation unit 30 in a first direction, a transport device 50 for transporting the printing medium A in a second direction intersecting the first direction, and a control unit 60. Each of the plurality of light source rows 33 is composed of a plurality of light sources 31 arranged in a row along the second direction, and the plurality of light source rows 33 are arranged in the first direction. The control unit 60 performs a first acquisition operation to acquire the distance between the light irradiation unit 30 and the printing medium A, a second acquisition operation to acquire temperature information of the light irradiation unit 30, and a printing operation to print an image on the printing medium A with ink. In the printing operation, the control unit 60 alternately performs a pass process in which the head 20 and the light irradiation unit 30 are moved in a first direction, ink is ejected from the head 20 onto the printing medium A, and light is irradiated onto the ink on the printing medium A from the light irradiation unit 30, and a transport process in which the printing medium A is transported in a second direction. In the pass process, if the interval is a second predetermined interval which is smaller than the first predetermined interval, the control unit 60 reduces the number of light source rows 33 that are lit out of the multiple light source rows 33, and determines which light source rows 33 to be lit based on temperature information.
[0063] The control method for this printing device 10 is performed by the control unit 60, for example, according to the flowchart in Figure 6. In this flowchart, the control unit 60 performs the process of step S5 between the processes of step S2 and step S3 in Figure 4.
[0064] Specifically, when the control unit 60 acquires image data (step S1: YES), it performs a first acquisition operation (step S2) and then a second acquisition operation (step S5). In this second acquisition operation, the control unit 60 acquires temperature information of the light irradiation unit 30.
[0065] For example, during a printing operation, the light source 31 of the light irradiation unit 30 is lit, causing the unit to heat up. Therefore, the control unit 60 obtains the lighting time of the light source 31 from the storage unit 63 as temperature information for the light irradiation unit 30. This lighting time of the light source 31 may include, for example, the lighting time of the light source 31 in all or a predetermined number of printing operations performed up to the current printing operation. The predetermined number of printing operations refers to one or more printing operations that are close to the current printing operation among all printing operations.
[0066] In this case, when the control unit 60 controls the on and off of the light source 31 for each light source row 33, it measures the on time of each light source row 31, from on to off. The control unit 60 then accumulates the measured time for each light source row 33 over a predetermined period, acquires the accumulated measured time for each light source row 33 as temperature information, and stores it in the storage unit 63. The longer the measured time, the longer the on time of the light source 31 in the light source row 33, and the higher the temperature of the light source 31 is associated with the temperature information.
[0067] Next, the control unit 60 executes a printing operation (step S3). In this printing operation, the control unit 60 alternately executes pass processing and transport processing. In pass processing, the control unit 60 executes a movement operation to move the head 20 and the light irradiation unit 30 in the left and right directions, as well as an ejection operation to eject ink from the head 20 onto the printing medium A, and an irradiation operation to irradiate light onto the ink on the printing medium A from the light irradiation unit 30.
[0068] In this irradiation operation, the control unit 60 controls the blinking of the light sources 31 for each light source row 33 and for each pass, according to the irradiation interval between the light irradiation unit 30 and the printing medium A. In the example in Figure 5, when the irradiation interval is large, equal to the first predetermined interval, the control unit 60 lights up the light sources 31 of all light source rows 33 from the first light source row 331 to the sixth light source row 336 in the light irradiation unit 30. As a result, many light sources 31 are lit, causing the ink on the printing medium A to harden.
[0069] On the other hand, if the irradiation interval is shorter than the second predetermined interval and the first predetermined interval, the control unit 60 lights up all the light sources 31 of some of the light source rows 33 in the light irradiation unit 30, and turns off all the light sources 31 of the other light source rows 33. The control unit 60 determines which light source rows 33 to light up based on the temperature information acquired in the second acquisition operation of step S5. For example, the control unit 60 acquires the lighting time of the light source rows 33 up to the current printing operation from the temperature information and decides to light up the light source rows 33 with low temperatures, i.e., those with short lighting times. At this point, one or more light source rows 33 that can provide the ink with the accumulated light amount necessary for ink curing are lit.
[0070] In this way, by turning off the light source array 33, which has a high temperature, in the light irradiation unit 30, thermal degradation due to the light emission of the light source 31 of the light source array 33 can be reduced. This reduces the need to replace the light irradiation unit 30 and extends its lifespan. Furthermore, when the irradiation interval is the second predetermined interval, fewer light sources 31 are lit than when the irradiation interval is the first predetermined interval, thus saving energy in the light irradiation unit 30. Moreover, when the irradiation interval is the second predetermined interval, the intensity of light emitted from the light irradiation unit 30 is lower than when the irradiation interval is the first predetermined interval, thus reducing thermal degradation of the printing medium A due to light.
[0071] In the example described above, when the irradiation interval is the second predetermined interval, the control unit 60 determined which light source array 33 to light up from among all the light source arrays 33 in the light irradiation unit 30 based on temperature information. Alternatively, the control unit 60 may determine which light source array 33 to light up from among all the light source arrays 33 in the light irradiation unit 30, excluding the central light source array 33c, based on temperature information. In this case, all the light sources 31 in the central light source array 33c, which tend to become hot, are turned off regardless of temperature information, thereby reducing thermal degradation of the central light source array 33c and extending the lifespan of the light irradiation unit 30.
[0072] Furthermore, in the example described above, when the irradiation interval is a second predetermined interval, the control unit 60 determined which light source array 33 to light up based on temperature information. In addition, the control unit 60 may determine which light source array 33 to light up based on both temperature information and image data. In this case, the control unit 60 obtains the lighting time of the light source array 33 up to the current printing operation from the temperature information, and also obtains the lighting time of the light source 31 during the current printing operation from the image data. Then, based on the lighting time up to the current printing operation and the lighting time of the current printing operation, the control unit 60 may determine which light source array 33 to light up for each pass, one or more times, so that the lighting time of the light source array 33 is equal.
[0073] Furthermore, all of the above embodiments may be combined with each other, provided that they do not exclude one another. Also, many improvements and other embodiments of the present invention will be apparent to those skilled in the art from the above description. Therefore, the above description should be interpreted as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of its structure and / or function can be substantially modified without departing from the spirit of the invention. [Industrial applicability]
[0074] The printing apparatus according to the present invention is useful as a printing apparatus that can extend the lifespan of the light irradiation unit. [Explanation of symbols]
[0075] 10:Printing device 20: Head 21: Nozzle 30: Light irradiation area 31:Light source 33:Light source row 33a: One end light source row 33b: Other end light source row 33c: Central light source row 33d: Medium light source row 40: Mobile device 50: Conveying device 60: Control Unit
Claims
1. A head having multiple nozzles for ejecting light-curing ink onto a printing medium, A light irradiation unit having multiple rows of light sources that irradiate light onto the ink on the printing medium, A moving device for moving the head and the light irradiation unit in a first direction, It comprises a control unit and, Each of the multiple light source rows is composed of multiple light sources arranged in a row along a second direction that intersects the first direction. The plurality of light source rows are arranged in the first direction and include one-end light source row and the other-end light source row provided at both ends in the first direction, and at least one central light source row provided in the middle between the one-end light source row and the other-end light source row. The control unit, A first acquisition operation to acquire the distance between the light irradiation unit and the printing medium, An ejection operation in which ink is ejected from the head onto the printing medium, The light irradiation unit is used to irradiate the ink on the printing medium with light, and the irradiation operation is performed. In the aforementioned irradiation operation, When the interval is a first predetermined interval, the one-end light source row, the other-end light source row, and the central light source row are turned on. If the interval is smaller than the first predetermined interval, the one-end light source array and the other-end light source array are turned on, and at least one of the central light source arrays is turned off. Printing device.
2. A head having multiple nozzles for ejecting light-curing ink onto a printing medium, A light irradiation unit having multiple rows of light sources that irradiate light onto the ink on the printing medium, A moving device for moving the head and the light irradiation unit in a first direction, A conveying device for conveying the printing medium in a second direction intersecting the first direction, It comprises a control unit and, Each of the multiple light source rows is composed of multiple light sources arranged in a row along the second direction. The plurality of light source rows are arranged in the first direction and include one-end light source row and the other-end light source row provided at both ends in the first direction, and a plurality of intermediate light source rows provided between the one-end light source row and the other-end light source row. The control unit, A first acquisition operation to acquire the distance between the light irradiation unit and the printing medium, A printing operation is performed in which an image is printed onto the printing medium using ink. In the aforementioned printing operation, A pass process in which the head and the light irradiation unit are moved in the first direction, ink is ejected from the head onto the printing medium, and light is irradiated from the light irradiation unit onto the ink on the printing medium, The transport process of transporting the printing medium in the second direction is performed alternately. In the aforementioned path processing, When the interval is the first predetermined interval, the one-end light source array, the other-end light source array, and the multiple intermediate light source arrays are turned on. If the interval is smaller than the first predetermined interval, the one-end light source array and the other-end light source array are turned on, and some of the intermediate light source arrays are turned on in a manner that changes with each pass processing, while the other intermediate light source arrays are turned off. Printing device.
3. A head having multiple nozzles for ejecting light-curing ink onto a printing medium, A light irradiation unit having multiple rows of light sources that irradiate light onto the ink on the printing medium, A moving device for moving the head and the light irradiation unit in a first direction, A conveying device for conveying the printing medium in a second direction intersecting the first direction, It comprises a control unit and, Each of the multiple light source rows is composed of multiple light sources arranged in a row along the second direction, and the multiple light source rows are arranged in the first direction. The control unit, A first acquisition operation to acquire the distance between the light irradiation unit and the printing medium, A printing operation is performed in which an image is printed onto the printing medium using ink. In the aforementioned printing operation, A pass process in which the head and the light irradiation unit are moved in the first direction, ink is ejected from the head onto the printing medium, and light is irradiated from the light irradiation unit onto the ink on the printing medium, The transport process of transporting the printing medium in the second direction is performed alternately. In the aforementioned path processing, If the interval is a second predetermined interval which is smaller than the first predetermined interval, the number of light source rows to be lit among the plurality of light source rows is reduced, and the light source rows to be lit are changed for each pass processing. Printing device.
4. A head having multiple nozzles for ejecting light-curing ink onto a printing medium, A light irradiation unit having multiple rows of light sources that irradiate light onto the ink on the printing medium, A moving device for moving the head and the light irradiation unit in a first direction, A conveying device for conveying the printing medium in a second direction intersecting the first direction, It comprises a control unit and, Each of the multiple light source rows is composed of multiple light sources arranged in a row along the second direction, and the multiple light source rows are arranged in the first direction. The control unit, A first acquisition operation to acquire the distance between the light irradiation unit and the printing medium, A second acquisition operation to acquire temperature information of the light irradiation unit, A printing operation is performed in which an image is printed onto the printing medium using ink. In the aforementioned printing operation, A pass process in which the head and the light irradiation unit are moved in the first direction, ink is ejected from the head onto the printing medium, and light is irradiated from the light irradiation unit onto the ink on the printing medium, The transport process of transporting the printing medium in the second direction is performed alternately. In the aforementioned path processing, If the interval is a second predetermined interval which is smaller than the first predetermined interval, the number of light source rows to be lit among the plurality of light source rows is reduced, and the light source rows to be lit are determined based on the temperature information. Printing device.