Printing apparatus

Abstract

To provide a printer capable of printing with reduced stains on a print medium having been wound in a roll.SOLUTION: A printing apparatus includes a platen 11 for supporting a print medium A pulled out from a roll in which the print medium A is wound in a roll, a transport unit 40 for transporting the print medium on the platen in a first direction, a head 20 that prints in a second direction intersecting the first direction an image on the print medium supported by the platen, a corrugate-shape former 30 shaping the print medium into a corrugated shape, and a cutter 60 cutting the print medium, in which the corrugate-shape former is provided with a plurality of ribs 31 arranged spacing apart in a third direction intersecting the first direction and the second direction and projecting from the platen in the second direction and a pressing portion 33 that presses the print medium toward the platen between the ribs that are adjacent to each other in the third direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0006] , , , ,

[0001] The present invention relates to a printing apparatus.

Background Art

[0002] As a conventional printing apparatus, for example, a recording apparatus disclosed in Patent Document 1 is known. This recording apparatus includes a cutter means for cutting a roll-shaped recording paper and a printing head for recording information on the cut recording paper with ink.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described recording apparatus, the roll-shaped recording paper is pulled out and cut by the cutter means, and then the recording paper is printed by the printing head. Since the recording paper was wound in a roll shape, the cut recording paper is curled. Therefore, the recording paper may come into contact with the printing head and be soiled with ink.

[0005] In view of such a situation, an object of the present invention is to provide a printing apparatus that can prevent a printing medium wound in a roll shape from contacting a head when an image is printed on the printing medium.

Means for Solving the Problems

[0006] A printing apparatus according to one aspect of the present invention comprises a platen that supports a printing medium drawn out from a roll in which the printing medium is wound in a roll shape; a conveying device that conveys the printing medium in a first direction on the platen; a head that prints an image on the printing medium supported by the platen in a second direction intersecting the first direction; a corrugator that gives the printing medium a wavy shape; and a cutter that cuts the printing medium, wherein the corrugator has a plurality of ribs that are spaced apart in a third direction intersecting the first and second directions and protruding from the platen in the second direction, and a pressing portion that presses the printing medium toward the platen between adjacent ribs in the third direction. [Effects of the Invention]

[0007] The present invention has the effect of providing a printing apparatus that can print on a printing medium wound in a roll shape while reducing contamination.

[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 view from the right of a printing apparatus according to an embodiment of the present invention. [Figure 2] This is a top-down view of a printing machine. [Figure 3] This is a view from the right of the corrugated and conveying device as the printing medium moves along the ribs. [Figure 4] This is a view from the right of the corrugated and conveying device when the printing medium moves between the pressing section and the platen. [Figure 5] This is a top view of the corrugated and downstream rollers. [Figure 6] Figure 6(a) is a front view of the corrugated and platen. Figure 6(b) is a front view of the downstream roller and spur. [Figure 7] This figure shows the relationship between the trailing edge of the print medium and the restricted area in each pass. [Figure 8] This figure shows the nozzle utilization rate and the transport distance of the printing medium in each pass. [Figure 9] This is a front view of the carriage and cutter of the printing apparatus according to Modification 1. [Figure 10] Figure 9 shows the carriage and cutter viewed from the right. [Figure 11] This is a view from the right of the carriage and cutter of the printing apparatus according to Modification 2. [Figure 12] Figure 11 shows a top view of the corrugated and downstream rollers. [Figure 13] Figure 13(a) is a view of the ribs and blades of Figure 11 from the right. Figures 13(b) and 13(c) are views of the ribs and blades of a printing apparatus relating to other modifications, also viewed from the right. [Modes for carrying out the invention]

[0010] (Embodiment) <Printing device configuration> In one embodiment of the present invention, the printing apparatus 10, as shown in the example in Figures 1 and 2, is an inkjet printer that prints an image on a printing medium A using ink ejected from a head 20. The printing apparatus 10 is a serial head type and comprises a head 20, a platen 11, a supply tray 12, an output tray 13, a corrugated tray 30, a transport device 40, a scanning device 50, a cutter 60, and a control device 70.

[0011] The first direction in which the printing medium A is transported by the transport device 40 on the platen 11 is referred to as the front, and the opposite direction is referred to as the rear. The second direction, which intersects the first direction and in which the head 20 and platen 11 are aligned, is referred to as the up-down direction, with the direction of the head 20 above the platen 11 being referred to as the up, and the opposite direction being referred to as the down. The third direction, which intersects the first and second directions, is referred to as the left-right direction. However, the arrangement of the printing device 10 is not limited to these.

[0012] The head 20 has a plurality of nozzles 21, a discharge surface 22 through which the nozzles 21 open, and a plurality of drive elements 23. The plurality of nozzles 21 are arranged in a row at intervals in the front-rear direction. The drive element 23 is, for example, a piezoelectric element, which is provided corresponding to the nozzle 21 and applies a discharge pressure to the ink. The ink is pressurized and discharged from the nozzle 21, and lands on the printing surface of the printing medium A facing the discharge surface 22. Thereby, dots by the ink are formed on the printing medium A, and an image by the plurality of dots is printed. <> <>

[0013] <> The scanning device 50 has a carriage 51, a scanning rail 52, an endless belt 53a, and a scanning motor 53. The scanning rail 52 extends in the left-right direction. The carriage 51 mounts the head 20 and is supported by the scanning rail 52 so as to be movable in the left-right direction along the scanning rail 52. The endless belt 53a extends long in the left-right direction along the scanning rail 52, is attached to the carriage 51, and is connected to the scanning motor 53 via a pulley 53b. The power of the scanning motor 53 is transmitted to the endless belt 53a via the pulley 53b, and the carriage 51 moves along the scanning rail 52. Thereby, the ink is discharged from the discharge surface 22 of the head 20 moving along the scanning rail 52 to the printing medium A, and dots by the ink are formed in the left-right direction. <> <>

[0014] <> The platen 11 is disposed below the head 20 and has an upper surface facing the discharge surface 22 in the vertical direction. The platen 11 supports the printing medium A disposed on its upper surface and defines the distance between the printing medium A and the discharge surface 22 in the vertical direction. The supply tray 12 is disposed below the platen 11, and the printing medium A is disposed on its upper surface. The printing medium A is, for example, a long sheet such as paper and cloth, and is wound around a roll shaft 14 extending in the left-right direction to form a roll R. The printing medium A is pulled out from the roll R wound in a roll shape and is disposed on the supply tray 12 so that its printing surface faces the upper surface of the supply tray 12. <> <>

[0015] <> The conveying device 40 has, for example, a supply roller 41, a guide 42, an upstream roller 43, a downstream roller 44, and a discharge roller 45. The supply roller 41 is below the platen 11, above the supply tray 12, and is arranged behind the roll R. The supply roller 41 has its axis extending in the left - right direction, is provided with a supply motor 41a, and rotates about the axis by the supply motor 41a. The supply roller 41 rotates while contacting the printing medium A on the supply tray 12 pulled out from the roll R, and conveys the printing medium A backward. The guide 42 is above the supply roller 41, below the upstream roller 43, and is arranged behind the supply roller 41 and the upstream roller 43. The front surface of the guide 42 is curved in a U - shape so as to be recessed backward. The printing medium A conveyed by the supply roller 41 moves along the entire surface of the guide 42, and changes its moving direction from backward to forward while moving upward.

[0016] The upstream roller 43 is above the supply roller 41 and behind the platen 11, and has a driving upstream roller 43a and a driven upstream roller 43b. The driving upstream roller 43a and the driven upstream roller 43b have their axes extending in the left - right direction and are arranged vertically so as to be able to sandwich the printing medium A therebetween. The driving upstream roller 43a is provided with an upstream motor 43c and rotates about the axis by the upstream motor 43c. The driven upstream roller 43b sandwiches the printing medium A between it and the driving upstream roller 43a, and rotates about the axis while contacting the printing medium A in conjunction with the rotation of the driving upstream roller 43a. Thereby, the printing medium A is conveyed forward by the upstream roller 43 and moves forward on the platen 11 between the head 20 arranged in front of the upstream roller 43 and the platen 11.

[0017] The downstream roller 44 is positioned above the supply roller 41 and in front of the platen 11, and has a driven downstream roller 44a and a driven downstream roller 44b. The driven downstream roller 44a and the driven downstream roller 44b have axes that extend in the left-right direction and are arranged vertically so that the printing medium A can be sandwiched between them. The driven downstream roller 44a is equipped with a downstream motor 44c and rotates around its axis by the downstream motor 44c. The driven downstream roller 44b sandwiches the printing medium A between itself and the driven downstream roller 44a and rotates around its axis in conjunction with the rotation of the driven downstream roller 44a, while contacting the printing medium A. As a result, the printing medium A is conveyed forward by the downstream roller 44 and moves forward from the platen 11, which is positioned behind the downstream roller 44.

[0018] The discharge roller 45 is positioned above the supply roller 41 and in front of the downstream roller 44, and includes a driven discharge roller 45a and a driven discharge roller 45b. The axes of the driven discharge roller 45a and the driven discharge roller 45b extend in the left-right direction and are arranged vertically so that a printing medium A can be sandwiched between them. The driven discharge roller 45a is equipped with a discharge motor 45c and rotates around its axis by the discharge motor 45c. The driven discharge roller 45b sandwiches the printing medium A between itself and the driven discharge roller 45a and rotates around its axis in conjunction with the rotation of the driven discharge roller 45a, while contacting the printing medium A. As a result, the printing medium A is transported forward by the discharge roller 45 and moves to the cutter 60 located in front of the discharge roller 45.

[0019] The cutter 60 is positioned in front of the discharge roller 45. The cutter 60 includes a blade 61, a holder 62, a cutter rail 63, an annular belt 64a, and a cutter motor 64. The cutter rail 63 extends laterally above the printing medium A conveyed by the discharge roller 45. The holder 62 holds the blade 61 and is supported on the cutter rail 63 so as to be movable laterally along the cutter rail 63. The annular belt 64a extends laterally along the cutter rail 63, is attached to the holder 62, and is connected to the cutter motor 64 via a pulley 64b. Power from the cutter motor 64 is transmitted to the annular belt 64a via the pulley 64b, causing the holder 62 to move along the cutter rail 63. As a result, the printing medium A conveyed by the discharge roller 45 is cut by the blade 61 moving along the cutter rail 63. The cut printing medium A is discharged to a discharge tray 13 positioned in front of the cutter 60.

[0020] The printing medium A is cut by the cutter 60 after the trailing edge of a single image. As a result, the cut printing medium A has a printed area where the image is printed, and an unprinted area in front of the printed area where the image is not printed. The cut printing medium A may be further cut between the printed area and the unprinted area. The printing medium A of the printed area may be discharged to the discharge tray 13, and the printing medium A of the unprinted area may be discharged to a different supply tray from the supply tray 12. The printing medium A of the unprinted area may then be supplied onto the platen 11 from the other supply tray by the conveying device 40. The blade 61 may be a flat blade or a disc-shaped rotating blade. If the blade 61 is a rotating blade, a rotary motor is provided in the cutter 60 so that the blade 61 rotates around its axis, and the drive of the rotary motor is controlled by the control device 70.

[0021] The control device 70 is a computer including a CPU and other circuits, and is electrically connected to the drive element 23 of the head 20, the scanning motor 53 of the scanning device 50, the supply motor 41a, upstream motor 43c, downstream motor 44c and discharge motor 45c of the transport device 40, and the cutter motor 64 of the cutter 60, and controls the driving of these. The control device 70 performs a printing process to print an image on the printing medium A by alternately executing a pass that ejects ink from the head 20 while moving the head 20 to the left or right, and a transport operation that transports the printing medium A. Then, the control device 70 performs a cutting process to cut the printed printing medium A.

[0022] <Corrugated> As shown in Figures 3 to 6, the platen 11 supports the printing medium A as it is drawn out from the roll R in which the printing medium A is wound into a roll. The corrugated 30 has a plurality of ribs 31 that are spaced apart in the left-right direction and protrude from the platen 11 in the up-down direction, and a pressing member 32 that presses the printing medium A toward the platen 11 between adjacent ribs 31 in the left-right direction, thereby creating a wavy shape on the printing medium A. The conveying device 40 is equipped with spurs 46 in front of the platen 11.

[0023] Specifically, the platen 11 is, for example, flat and longer than the printing medium A in the left-right direction. The upper surface of the platen 11 is flat and faces the discharge surface 22 of the head 20. In the vertical direction, the upper surface of the platen 11 is positioned below the clamping position of the printing medium A between the driven upstream roller 43a and the driven upstream roller 43b of the upstream roller 43, and below the clamping position of the printing medium A between the driven downstream roller 44a and the driven downstream roller 44b of the downstream roller 44.

[0024] The rib 31 is a flat plate shape that is long in the front-rear direction and thin in the left-right direction, with its lower end connected to the upper surface of the platen 11 and its upper end 31e facing the discharge surface 22. The length of the rib 31 in the front-rear direction is shorter than the length of the platen 11, and it is positioned closer to the rear end of the platen 11 than to the front end in the front-rear direction. Multiple ribs 31 are arranged at equal intervals in the left-right direction so that they overlap when viewed along the left-right direction. For example, if multiple ribs 31 have the same shape and size as each other, the rear ends of the ribs 31 are in the same position as each other in the front-rear direction, and the front ends of the ribs 31 are in the same position as each other. The upper end 31e of the rib 31 is positioned in the same position as or slightly below the clamping position of the upstream roller 43 and in the same position as or above the clamping position of the downstream roller 44 in the vertical direction.

[0025] The rear end of the pressing member 32 is fixed to the scanning rail 52 (Figure 1) or the like, behind the upstream roller 43. The pressing member 32 extends forward from its rear end above the upstream roller 43, extends downward in front of the upstream roller 43, and further extends forward above the platen 11. The portion that extends forward in front of the upstream roller 43 functions as a pressing section 33 that presses the printing medium A toward the platen 11. The pressing section 33 is positioned at intervals between adjacent ribs 31 so that it overlaps with the ribs 31 when viewed along the left-right direction. The pressing section 33 is shorter than the ribs 31 in the front-rear direction, and its front end is positioned behind the front end of the ribs 31. In the vertical direction, the pressing section 33 is positioned below the clamping position of the upstream roller 43 and the clamping position of the downstream roller 44. The pressing section 33 is positioned above the upper surface of the platen 11 and below the upper end 31e of the ribs 31.

[0026] In this way, the corrugated surface 30 has ribs 31 and pressing portions 33 arranged alternately in the left-right direction. In this corrugated surface 30, the printing medium A is pushed up above the pressing portions 33 by the ribs 31 to form a peak shape, and is also pushed down below the upper end 31e of the ribs 31 by the pressing portions 33 to form a valley shape. As a result, the printing medium A is given a wave shape in which peaks and valleys are arranged alternately in the left-right direction.

[0027] The downstream rollers 44 are provided in the same number as the ribs 31, and the multiple downstream rollers 44 are arranged at equal intervals in the left-right direction. The downstream rollers 44 are positioned in front of the platen 11. The downstream rollers 44 are positioned in the same position as the ribs 31 in the left-right direction, so as to overlap with the ribs 31 when viewed along the front-rear direction. The gripping position of the downstream rollers 44 is above the pressing portion 33 in the vertical direction, and is positioned at the same position as or slightly below the upper end 31e of the ribs 31. Therefore, the mountain-shaped portion of the printing medium A that is pushed up by the ribs 31 is gripped by the driven downstream roller 44a and the driven downstream roller 44b of the downstream rollers 44, and is conveyed forward while maintaining its mountain shape.

[0028] Multiple spurs 46 are arranged at equal intervals in the left-right direction in front of the downstream roller 44. The spurs 46 are positioned in the same location as the pressing section 33 in the left-right direction, so as to overlap with the pressing section 33 when viewed in the front-rear direction. The spurs 46 are positioned between adjacent downstream rollers 44 in the left-right direction. The lower end of each spur 46 is positioned below the clamping position of the downstream roller 44 and the upper end 31e of the rib 31 in the vertical direction, and is positioned at the same location as or slightly below the pressing section 33. As a result, the valley-shaped portions of the printing medium A that are pressed down by the pressing section 33 are pressed down by the spurs 46, and are transported forward while maintaining their valley shape. This gives the printing medium A a wave shape in which peaks and valleys are arranged alternately in the left-right direction.

[0029] <Print Control> Next, the print control will be explained. Since the printing medium A is always supported by both the upstream roller 43 and the downstream roller 44, printing can be performed on the printing medium A using a single multi-pass method. In other words, in multi-pass printing, the control device 70 first divides the image data of the image to be printed into multiple sub-images, assigns each sub-image to multiple passes (for example, three passes), and performs printing based on the image data corresponding to each pass. Specifically, the ink dots ejected from the head 20 based on the first pass, the ink dots ejected from the head 20 based on the second pass, and the ink dots ejected from the head 20 based on the third pass are superimposed on the printing medium A to complete one sub-image. When a predetermined number of sub-images are completed, they become one image. When printing one image, if adjacent sub-images are separated or overlap due to uneven transport of the printing medium A, density unevenness occurs. To reduce this density unevenness, the usage rate of the nozzles 21 in the head 20 is adjusted for each pass. Here, the nozzle utilization rate is the proportion of the multiple nozzles 21 in the head 20 that are used to print the image.

[0030] For example, in the path P1-P7 that transports the printing medium A forward for a distance L1 as shown in Figure 8, the multiple nozzles 21 are divided into multiple (for example, three) groups in the front-to-back direction, as shown in Figure 7, and are designated as the front nozzle group 21a, the middle nozzle group 21b, and the rear nozzle group 21c. Each nozzle group contains multiple nozzles 21, and the front nozzle group 21a, the middle nozzle group 21b, and the rear nozzle group 21c are arranged in this order from front to back. The utilization rate of the nozzles 21 is higher for the middle nozzle group 21b than for the front nozzle group 21a and the rear nozzle group 21c, and decreases towards the front of the front nozzle group 21a, and towards the rear of the rear nozzle group 21c. Therefore, the utilization rate of the nozzles 21 is high in the middle nozzle group 21b and decreases as you move away from the middle nozzle group 21b in the front-to-back direction, resulting in a gradient. Furthermore, the front nozzle group 21a, middle nozzle group 21b, and rear nozzle group 21c may be configured such that unused nozzles 21 are positioned in front of the front nozzle group 21a and after the rear nozzle group 21c among the nozzles 21 in the head 20.

[0031] As shown in Figure 8, in passes P1-P7 of the printing process, the control device 70 moves the head 20 to the right or left, ejecting ink from the head 20 onto the printing medium A at a gradient nozzle utilization rate, forming ink dots D on the printing medium A. After forming the dots D in a pass, the control device 70 transports the printing medium A forward for a distance L1. This pass and transport operation is repeated. The distance L1 is equal to the length of the front nozzle group 21a in the front-to-back direction. As a result, the dot Dc from the rear nozzle group 21c in a pass P1, the dot Db from the middle nozzle group 21b in the next pass P2, and the dot Da from the front nozzle group 21a in the next pass P3 overlap on the printing medium A, forming an image. In this way, the same area on the printing medium A is printed in multiple passes (for example, 3 times). The number of dots Da, Db, and Dc in this area is equal to the number of dots that make up the image formed by these dots. This allows the image to be printed in just three passes.

[0032] <Mechanism of action, effect> Thus, since the printing medium A is drawn from a roll R that is wound in a roll shape, it curls more than cut paper. In contrast, the curling of the printing medium A is suppressed by the corrugation 30 which gives it a wavy shape. Therefore, contact between the printing medium A and the head 20 is suppressed, and the head 20 can print an image onto the printing medium A while reducing the amount of ink from the head 20 on the printing medium A.

[0033] Furthermore, the cutter 60 is positioned in front of the downstream roller 44. As a result, the printing medium A moves forward on the platen 11 between the upstream roller 43 and the downstream roller 44, is printed on by the head 20, and then cut by the cutter 60 in front of the downstream roller 44. In this way, even after a portion of the printing medium A has been cut by the cutter 60, the printing medium A is still supported by both the upstream roller 43 and the downstream roller 44 between the platen 11 and the head 20. This suppresses contact between the printing medium A and the head 20, reducing contamination of the printing medium A with ink from the head 20, while still allowing the head 20 to print an image onto the printing medium A.

[0034] In this embodiment, the cutter 60 is positioned in front of the downstream roller 44. In contrast, if the cutter 60 were positioned behind the upstream roller 43, there is a risk that the printing medium A would come into contact with the head 20. In this case, there is a risk that the printing medium A would be contaminated by the ink from the head 20. Furthermore, if debris such as fragments and adhering materials of the printing medium A adhere to the discharge surface 22 of the head 20 and overlap with the nozzle 21 that opens into the discharge surface 22, there is a risk that the nozzle 21 may malfunction, changing the direction of ink discharge or obstructing ink discharge.

[0035] There are three main causes for these problems. First, the printing medium A is cut by the cutter 60 and has a trailing end A1 between, for example, the upstream roller 43 and the downstream roller 44. As a result, the printing medium A is cantilevered by the downstream roller 44. Therefore, the printing medium A is more likely to come into contact with the head 20 between the upstream roller 43 and the downstream roller 44. Second, ribs 31 are provided to give the printing medium A a wavy shape. As a result, the ribs 31 lift the printing medium A, bringing it closer to the discharge surface 22 of the head 20, making it easier for the printing medium A to come into contact with the head 20. Third, because the printing medium A is wound around the roll shaft 14 to form a roll R, it has a curl. When the printing medium A has a curl, it curves compared to cut paper, bringing it closer to the head 20 and making it more likely to come into contact with the head 20.

[0036] Thus, the printing medium A is cantilevered by the downstream roller 44, lifted by the rib 31, and has a curl, so it may come into contact with the head 20. In such cases, problems such as soiling of the printing medium A and poor ejection of the nozzle 21 may occur. Therefore, it is conceivable to provide a restricting area B in order to reduce contact with the head 20. The restricting area B is the area in which, after the rear end A1 of the printing medium A enters and transport and printing are repeated, the rear end A1 of the printing medium A is supported by the rib 31 and the printing medium A is printed in a cantilevered state supported by the downstream roller 44.

[0037] First, we will explain the case where no problem occurs, that is, the case where the trailing edge A1 of the printing medium A does not enter the restricted area B. In this case, in the area of ​​the printing medium A closest to the trailing edge A1, one of the printing mediums A may be cantilevered by the downstream roller 44. In this case, the support of the printing medium A becomes unstable, which negatively affects the image quality. To address this, in order to reduce the area of ​​the image that is negatively affected in image quality, the number of nozzles 21 used from among the multiple nozzles 21 in the head 20 is reduced.

[0038] Furthermore, the control device 70 causes the printing medium A to be transported to the transport device 40 between pass P7 and the next pass P8 over a distance L2 shorter than the distance L1. In pass P8, the control device 70 prevents the head 20 from using the nozzle 21 corresponding to the area C that overlaps with dot Da by pass P7. Also, the control device 70 reduces the utilization rate of the nozzle 21 for the group of nozzles corresponding to dot Dd that overlaps with dot Db by pass P7, as it moves forward. Furthermore, the control device 70 makes the utilization rate of the nozzle 21 for the group of nozzles corresponding to dot De that overlaps with dot Dc by pass P7 the same as the middle nozzle group 21b. The control device 70 reduces the utilization rate of the nozzle 21 for the group of nozzles corresponding to dot Df that is after dot De by pass P8, as it moves later.

[0039] After pass P8, the control device 70 transports the printing medium A to the transport device 40 over a distance L2 and executes pass P9. In pass P9, the control device 70 prevents the head 20 from using the nozzle 21 corresponding to the area C that overlaps with the dot Dd from pass P8. The control device 70 also reduces the utilization rate of the nozzle 21 for the group of nozzles corresponding to the dot Dg that overlaps with the dot De from pass P8, decreasing it as it moves forward. Furthermore, the control device 70 sets the utilization rate of the nozzle 21 for the group of nozzles corresponding to the dot Dh that overlaps with the dot Df from pass P8 to be the same as the middle nozzle group 21b. The control device 70 also reduces the utilization rate of the nozzle 21 for the group of nozzles corresponding to the dot Di that is after the dot Dh from pass P9, decreasing it as it moves later.

[0040] After pass P9, the control device 70 transports the printing medium A to the transport device 40 over a distance L2 and executes pass P10. In pass P10, the control device 70 prevents the head 20 from using the nozzle 21 corresponding to the area C that overlaps with dot Dg from pass P9. Furthermore, the control device 70 reduces the utilization rate of the nozzle 21 for the group of nozzles corresponding to dot Dj that overlaps with dot Dh from pass P9, decreasing it towards the front. In addition, the control device 70 makes the utilization rate of the nozzle 21 for the group of nozzles corresponding to dot Dk that overlaps with dot Di from pass P9 the same as the middle nozzle group 21b. The control device 70 reduces the utilization rate of the nozzle 21 for the group of nozzles corresponding to dot Dl that is after dot Dk from pass P10, decreasing it towards the back. Note that, as shown in Figure 7, the trailing end A1 of the printing medium A does not enter the restricted area B.

[0041] After pass P10, the control device 70 transports the printing medium A to the transport device 40 over a distance L3 that is longer than distance L2, and executes pass P11. In pass P11, the control device 70 reduces the utilization rate of nozzles 21 towards the front for the nozzle group corresponding to dot Dm that overlaps with dot Dk from pass P10. Furthermore, the control device 70 makes the utilization rate of nozzles 21 the same as the middle nozzle group 21b for the nozzle group corresponding to dot Dn that overlaps with dot Dl from pass P10. The control device 70 reduces the utilization rate of nozzles 21 towards the back for the nozzle group corresponding to dot Do that is after dot Dn from pass P11. The control device 70 does not allow the head 20 to use nozzles 21 corresponding to region C after dot Do from pass P11.

[0042] After pass P11, the control device 70 transports the printing medium A to the transport device 40 over a distance L2 and executes pass P12. In pass P12, the control device 70 reduces the utilization rate of the nozzles 21 corresponding to the nozzle group that overlaps with dot Dp from pass P11, decreasing as it moves forward. Furthermore, the control device 70 makes the utilization rate of the nozzles 21 corresponding to the nozzle group that overlaps with dot Dq from pass P11 the same as the middle nozzle group 21b. The control device 70 does not allow the head 20 to use the nozzles 21 corresponding to the area C after dot Dq from pass P12.

[0043] After pass P12, the control device 70 transports the printing medium A to the transport device 40 over a distance L2 and executes pass P13. In pass P13, the control device 70 reduces the utilization rate of the nozzles 21 corresponding to the nozzle group that overlaps with the dot Dq from pass P12, with the rate decreasing further forward. Furthermore, the control device 70 prevents the head 20 from using the nozzles 21 corresponding to the area C after the dot Dr from pass P13. In this way, the dots D from the three passes overlap, and the image is printed on the printing medium A. Thus, as shown in Figure 7, the trailing end A1 of the printing medium A does not enter the restricted area B, contact of the printing medium A with the head 20 is suppressed, and soiling of the printing medium A can be reduced.

[0044] Next, we will explain the case where a problem occurs, that is, when the rear end A1 of the printing medium A enters the restricted area B. As described above, in order to prevent the rear end A1 of the printing medium A from entering the restricted area B, the control device 70 performs a certain control in the area close to the rear end A1 of the printing medium A, for example, by transporting the printing medium A to the transport device 40 three times over a distance L2, and then once over a distance L3. However, since the cutter 60 cuts the printing medium A, the total length in the front-to-back direction of the cut printing medium A differs from one sheet to another. For this reason, even with the above transport control, the rear end A1 of the printing medium A may enter the restricted area B.

[0045] In this case, with the rear end A1 of the printing medium A entering the restricted area B, the control device 70 causes the printing medium A to be transported to the transport device 40 at a distance L3 that is longer than the distance L2. As a result, the printing medium A is printed on with the rear end A1 of the printing medium A supported by the rib 31 and the printing medium A supported in a cantilever manner by the downstream roller 44, and ink lands on the rear end A1. In this case, the distance between the printing medium A supported by the rib 31 and the head 20 is relatively close, and if the rear end A1 of the printing medium A bends due to the landed ink, the rear end A1 will come into contact with the head 20.

[0046] To avoid contact between the print medium A and the head 20, it is conceivable to transport the print medium A over a longer distance L4 than the distance L3. However, this cannot be adopted because interlace control would not be achieved, negatively impacting image quality. Here, in order for interlace control to be achieved, when printing a partial image divided into three passes, the sum of distances L2 and L3 must not exceed the length from the leading nozzle 21 to the last nozzle 21. Also, when printing a partial image divided into two passes, the sum of distances L2 and L3 must not exceed the length from the leading nozzle 21 to the last nozzle 21.

[0047] To address the aforementioned problem, the cutter 60 is positioned in front of the downstream roller 44, and the printing medium A is cut in front of the downstream roller 44, so it is supported from both sides by the upstream roller 43 and the downstream roller 44. Therefore, it is possible to print on the printing medium A using a multi-pass method while preventing contact between the printing medium A and the head 20, without causing the aforementioned problem.

[0048] <Example 1> The printing apparatus 10 according to Modification 1, as shown in Figures 9 and 10 above, includes a carriage 51 on which a head 20 is mounted and which moves the head 20 in the left-right direction. The cutter 60 is provided on the carriage 51. Here, the cutter 60 may be positioned in front of both the head 20 and the rib 31.

[0049] Specifically, the carriage 51 is provided with, for example, a housing chamber 54 that opens on its lower surface, and the cutter 60 is housed in the housing chamber 54. The housing chamber 54 and the cutter 60 are positioned in front of the head 20. Two first pins 55 are provided on the front surface 54a of the inner surface of the carriage 51 that forms the housing chamber 54. The two first pins 55 are spaced apart in the vertical direction and protrude forward from the front surface 54a.

[0050] The cutter 60 has a mounting plate 65, and a blade 61 is fixed to the lower end of the mounting plate 65. The rear surface of the mounting plate 65 faces the front surface 54a. The mounting plate 65 is provided with a first elongated hole 65a. The first elongated hole 65a is long in the vertical direction and penetrates the mounting plate 65 in the front-to-back direction. Two first pins 55 are passed through the first elongated hole 65a to attach the mounting plate 65 to the carriage 51. In this way, the cutter 60 is mounted on the carriage 51 so that it can move in the vertical direction.

[0051] The carriage 51 is equipped with a lever 66, a spring 67, and a solenoid 68. The lever 66 has its right end connected to a mounting plate 65 and its left end connected to the movable part 68a of the solenoid 68. The lever 66 has an axis 66a between its right and left ends. The axis 66a is connected to the front surface 54a and protrudes forward from the front surface 54a. The lever 66 is rotatable about the axis 66a. When the solenoid 68 is turned off, a counterclockwise force is applied to the lever 66 by the spring 67, raising the mounting plate 65 and moving the blade 61 to a retracted position S1 above the printing medium A and into the housing chamber 54. On the other hand, when the solenoid 68 is turned on, the movable part 68a of the solenoid 68 rises, and a clockwise force is applied to the lever 66 by the movable part 68a, the mounting plate 65 is lowered, and the blade 61 protrudes below the lower end of the carriage 51 and moves to the cutting position S2 in the transport path of the printing medium A. At the cutting position S2, the lower end of the blade 61 is positioned above the platen 11, in a position where it can cut the platen 11.

[0052] In the printing process, with the blade 61 in the retracted position S1, the printing medium A is given a wavy shape by the corrugated 30 and then printed by the head 20 which moves in the left-right direction. When the trailing edge of one image printed by the head 20 on the printing medium A is transported in front of the blade 61 by the transport device 40, the control device 70 stops the transport device 40 and turns on the solenoid 68 which is in the off state, causing the carriage 51 to move in the left-right direction. As a result, the blade 61 is lowered from the retracted position S1 to the cutting position S2 and moves in the left-right direction, so the printing medium A is cut by the blade 61. Then, the control device 70 turns off the solenoid 68 which was in the on state, moving the blade 61 from the cutting position S2 to the retracted position S1 and storing it in the storage chamber 54. The control device 70 also drives the transport device 40 to transport the printing medium A after the cutting point forward by the upstream roller 43 and the printing medium A before the cutting point forward by the downstream roller 44.

[0053] In this way, the printing medium A is given a wavy shape by the corrugation 30, which prevents the printing medium A from coming into contact with the head 20, while still allowing printing by the head 20. Furthermore, since the cutter 60 is mounted on the carriage 51, the printing apparatus 10 does not need to be equipped with a dedicated moving device for moving the cutter 60 in the left-right direction, thus reducing the number of parts.

[0054] Furthermore, the cutter 60 is positioned in front of the head 20. As a result, when the printing medium A is cut by the cutter 60, the rear end A1 and front end of the printing medium A are formed in front of the head 20, thus suppressing contact of the printing medium A with the head 20. Also, the cutter 60 is positioned in front of the rib 31. As a result, the rear end A1 and front end of the printing medium A are not lifted by the rib 31, thus suppressing contact of the printing medium A with the head 20. Also, the cutter 60 is positioned in front of both the head 20 and the rib 31. As a result, while the printing medium A is being printed, it can be supported from both sides by the upstream roller 43 and the downstream roller 44, thus preventing contact of the printing medium A with the head 20. In this way, printing can be done on the printing medium A using a multi-pass method.

[0055] <Modification 2> In the second modified example of the printing apparatus 10, as shown in Figures 9, 11, and 12, the cutter 60 is provided on the carriage 51. Here, the cutter 60 may be positioned behind the head 20. The cutter 60 may also be positioned between the head 20 and the presser 33 in the front-rear direction. Furthermore, the cutter 60 may be positioned between one end and the other end of the rib 31 in the front-rear direction. The plurality of ribs 31 include a first rib 31a and a second rib 31b. The first rib 31a may have a first notch 34a that is recessed toward the platen 11 in the vertical direction, and the second rib 31b may have a second notch 34b that is recessed toward the platen 11 in the vertical direction. At least a portion of the first notch 34a and at least a portion of the second notch 34b may be in the same position in the front-rear direction. The cutter 60 may be positioned so as to be able to pass through the first notch 34a and the second notch 34b in the left-right direction.

[0056] Specifically, the cutter 60 is mounted on the carriage 51 so as to be movable in the vertical direction and is positioned behind the head 20. The blade 61 of the cutter 60 is positioned in front of the presser 33 and behind the head 20. This allows the cutter 60 to be positioned in the printing device 10 while reducing the increase in size in the front-to-back direction. In addition, the blade 61 is positioned on the rib 31 in the front-to-back direction, in front of the rear end of the rib 31 and behind the front end of the rib 31, so as to overlap the rib 31 when viewed along the vertical direction. This reduces the increase in size due to the cutter 60 in the front-to-back direction.

[0057] In the cutter 60, when the solenoid 68 is off, the blade 61 is housed in the storage chamber 54 at a retracted position S1 above the printing medium A, and when the solenoid 68 is on, the blade 61 is positioned at a cutting position S2 in the transport path of the printing medium A. At this cutting position S2, the blade 61 is positioned above the platen 11, with its lower end below the upper end 31e of the rib 31, so that it can print on the printing medium A on the platen 11.

[0058] The rib 31 has a notch 34. The notch 34 is located in front of the presser portion 33 and behind the head 20. The notch 34 is recessed downward from the upper end 31e of the rib 31 and penetrates the rib 31 in the left-right direction. As shown in Figure 13(a), the front surface 31f of the rib 31 that forms the rear end of the notch 34 is located behind the rear end of the blade 61. The rear surface 31r of the rib 31 that forms the front end of the notch 34 is located in front of the front end of the blade 61. The upper surface 31u of the rib 31 that forms the lower end of the notch 34 is located below the upper end 31e of the rib 31 and the lower end of the blade 61 in the vertical direction, and is located at the same position as or above the upper surface of the platen 11. In other words, the lower end of the notch 34 may be flush with the platen 11. This allows the blade 61 to pass through the notch 34, which is surrounded by the front surface 31f, the rear surface 31r, and the upper surface 31u, in the left-right direction. Furthermore, if the upper surface 31u of the rib 31 is at the same position as the upper surface of the platen 11 in the vertical direction, it may be formed by the upper surface of the platen 11.

[0059] As shown in Figure 12, in the multiple ribs 31 arranged in the left-right direction, the multiple notches 34 have the same shape and size as each other, for example, rectangular. The multiple notches 34 are positioned at the same location in the front-back direction, overlap each other when viewed along the left-right direction, and are aligned in a straight line in the left-right direction. As a result, as shown by the dashed line 61a in Figure 12, the blade 61 can move linearly in the left-right direction by passing through the multiple notches 34.

[0060] In the printing process, the control device 70 turns off the solenoid 68 to position the blade 61 in the retracted position S1, and the transport device 40 transports the printing medium A forward on the platen 11. On the platen 11, the printing medium A is given a wavy shape by the pressing portion 33 and ribs 31 of the corrugated 30. Then, the control device 70 ejects ink from the head 20 to print an image onto the printing medium A. When one image is printed on the printing medium A, the control device 70 stops the transport device 40 and the ejection of the head 20. When the ejection of the head 20 is stopped, there is a blank space between the trailing end A1 of the image A printed on the printing medium A and the position of the cutter 60 where no image has been printed. If this blank space is discarded without an image being printed, it will cause increased costs. Therefore, the control device 70 causes the printing medium A to be transported backward on the platen 11 by the transport device 40, and stops the transport when the position of the cutter 60 is aligned with a predetermined margin at the rear end of the image printed on the printing medium A. With the position of the cutter 60 aligned with the position of the image printed on the printing medium A, the solenoid 68, which is off, is turned on, and the carriage 51 is moved in the left-right direction. As a result, the blade 61 moves in the left-right direction at the cutting position S2 between the presser 33 and the head 20, cutting the printing medium A. Then, the printing medium A after the cutting position S2 is transported forward by the upstream roller 43, and the printing medium A before the cutting position S2 is transported forward by the downstream roller 44. When the printing medium A is cut, the control device 70 turns off the solenoid 68, moves the blade 61 to the retracted position S1 and stores it in the storage chamber 54, and transports the printing medium A by the transport device 40.

[0061] In this way, the printing medium A is given a wavy shape by the corrugation 30, which prevents the printing medium A from coming into contact with the head 20, while still allowing printing by the head 20. Furthermore, since the cutter 60 is mounted on the carriage 51, the printing apparatus 10 does not need to be equipped with a dedicated moving device for moving the cutter 60 in the left-right direction, thus reducing the number of parts. In addition, since the cutter 60 is positioned in front of the head 20 in the front-rear direction, the unprinted area of ​​the cut printing medium A can be kept small. Moreover, since the cutter 60 is positioned between the head 20 and the pressing part 33 in the front-rear direction, the printing medium A can be easily cut by the cutter 60 while the curl of the printing medium A is suppressed by the corrugation 30.

[0062] Furthermore, one image can be printed on the printing medium A while it is supported by both the upstream roller 43 and the downstream roller 44. In this case, it is not an issue whether the rear end A1 enters the restricted area B or not. After one image has been printed on the printing medium A, the control device 70 transports the printing medium A to the rear using the transport device 40 on the platen 11, and the cutter 60 cuts the printing medium A after aligning the position of the cutter 60 with a predetermined margin at the rear end of the image printed on the printing medium A. Therefore, even if the total length of each cut printing medium A differs, waste of printing medium A can be minimized.

[0063] In the modified example 2, as shown in the example in Figure 13(a), the multiple notches 34 had the same shape and size as each other. In this case, the multiple notches 34 overlap each other such that, when viewed along the left-right direction, the entirety of the first notch 34a of the first rib 31a and the entirety of the second notch 34b of the second rib 31b overlap. However, the shape and size of the notches 34 are not limited to this, as long as the blade 61 moving linearly in the left-right direction can pass through the multiple notches 34. For example, in the example in Figure 13(b), the second notch 34b is larger than the first notch 34a, and when viewed along the left-right direction, the entirety of the first notch 34a and a part of the second notch 34b overlap. In this overlapping area, the blade 61 can pass through the first notch 34a and the second notch 34b in the left-right direction. Furthermore, in the example shown in Figure 13(c), the first notch 34a and the second notch 34b are the same shape and size, but are offset from each other in the left-right direction, so that when viewed along the left-right direction, a portion of the first notch 34a and a portion of the second notch 34b overlap. Within this overlapping area, the blade 61 can pass through the first notch 34a and the second notch 34b in the left-right direction.

[0064] In the modified example 2, the cutter 60 may be positioned in front of the rib 31 between the head 20 and the pressing part 33 in the front-rear direction. In this case, since the rear end A1 and front end of the printing medium A are not lifted by the rib 31, contact of the printing medium A with the head 20 is suppressed. Also, one image can be printed on the printing medium A while it is supported from both sides by the upstream roller 43 and the downstream roller 44. In this case, whether or not the rear end A1 enters the restricted area B is not an issue. Furthermore, after one image has been printed on the printing medium A, the control device 70 transports the printing medium A to the rear on the platen 11 using the transport device 40, and the cutter 60 cuts the printing medium A after aligning the position of the cutter 60 with a predetermined margin at the rear end of the image printed on the printing medium A. Therefore, even if the total length of each cut printing medium A differs, waste of printing medium A can be minimized.

[0065] <Other variations> In the above embodiment and modified example 1-2, the control device 70 may, after causing the print medium A to print an image with the head 20, transport the print medium A to the rear using the transport device 40 on the platen 11, and then stop transporting the print medium A so that a predetermined margin is left at the rear end of the image printed on the print medium A and the position of the cutter 60 is aligned. Alternatively, the control device 70 may, after causing the print medium A to print an image with the head 20, transport the print medium A to the rear using the transport device 40 on the platen 11, and stop transporting the print medium A so that a predetermined margin is not left at the rear end of the image printed on the print medium A and the position of the cutter 60 is aligned. This enables so-called borderless printing.

[0066] 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]

[0067] This invention can be applied to a printing apparatus that can print on a printing medium wound in a roll shape while reducing contamination. [Explanation of Symbols]

[0068] 10:Printing device 11: Platen 20: Head 30: Corrugated 31: Rib 31a: First rib 31b: Second rib 33: Pressing part 34: Notch 34a: First notch 34b: Second notch 40: Conveyor equipment 43: Upper Laura 44: Downstream Laura 51: Carriage 60: Cutter

Claims

1. A platen that supports the printing medium as it is drawn out from a roll in which the printing medium is wound, A conveying device for conveying the printing medium in a first direction on the platen, A head for printing an image on the printing medium supported by the platen in a second direction intersecting the first direction, A corrugated surface that gives a wave shape to the aforementioned printing medium, A cutter for cutting the aforementioned printing medium, The carriage comprises the head on which the head is mounted and which moves the head in a third direction intersecting the first and second directions, The aforementioned corrugated section A plurality of ribs are spaced apart in the third direction and protrude from the platen in the second direction, It has a pressing portion that presses the printing medium toward the platen between the ribs adjacent to each other in the third direction, The cutter is provided on the carriage, It is positioned upstream of the head in the first direction, In the first direction, it is positioned between the head and the pressing portion, In the first direction, it is positioned between one end and the other end of the rib, The plurality of ribs include a first rib and a second rib, The first rib has a first notch that is recessed toward the platen in the second direction, The second rib has a second notch that is recessed toward the platen in the second direction, At least a portion of the first notch and at least a portion of the second notch are in the same position in the first direction, The cutter, after printing an image onto the printing medium, passes through the first notch and the second notch as the carriage moves together with the head in the printing apparatus.

2. The printing apparatus according to claim 1, wherein the cutter is arranged to pass through the first notch and the second notch in the third direction.

3. The second notch is larger than the first notch. The printing apparatus according to claim 1, wherein the entirety of the first notch and a portion of the second notch overlap.

4. The printing apparatus according to claim 1, wherein the first notch and the second notch are the same shape and size and are arranged at different positions in the first direction.

Images