Printing device and method for controlling printing device

Abstract

To prevent deterioration in an image quality caused by star wheels.SOLUTION: A printing device comprises: a printing head that forms an image on a recording medium by ejecting ink to the medium; a platen comprising a support surface for supporting the recording medium; and a recording medium pressing part, positioned closer a downstream than the printing head in a carrying direction of the recording medium and also positioned at a position opposing to the support surface, which can press the recording medium so that the medium approaches the support surface, in a direction perpendicular to the support surface, the recording medium pressing part holding star wheels. When the recording medium passes through between the support surface and the recording medium pressing part, when a maximum value of a height from the support surface in the direction perpendicular to the support surface of the recording medium is less than 2.2 mm, a load at which each of the star wheels presses the recording medium in a case that recording medium pressing part exists is 4.5 gf or less.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a printing apparatus and a method for controlling a printing apparatus. [Background technology]

[0002] Conventionally, as disclosed in Patent Document 1, there is known a printer that includes a print head that ejects ink, a platen unit having a platen surface that supports a medium, and a star wheel that presses the medium supported on the platen surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-193561 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above printers, for example, when a medium such as label paper is pressed with a star wheel, the protrusions of the star wheel can leave marks on the label paper, or the adhesive of the label paper can adhere to the tips of the protrusions of the star wheel, and if ink adheres to the adhesive, it can be transferred to another part of the label paper, resulting in a decrease in image quality. [Means for solving the problem]

[0005] The printing device includes a print head that ejects ink onto a recording medium to form an image, a platen having a support surface that supports the recording medium, and a recording medium pressing unit that is located downstream of the print head in the recording medium transport direction and facing the support surface, and that holds a plurality of star wheels that can press the recording medium toward the support surface in a direction perpendicular to the support surface, and when the recording medium passes between the support surface and the recording medium pressing unit, if the maximum height of the recording medium from the support surface in the direction perpendicular to the support surface is less than 2.2 mm, the load that each star wheel applies to press the recording medium is 4.5 gf or less, where the maximum value is the height of the recording medium from the support surface in the direction perpendicular to the support surface, and is the maximum value of the height of the recording medium from the support surface when it is assumed that the recording medium pressing unit does not exist.

[0006] a control method for a printing device including a print head that ejects ink onto a recording medium to form an image; a platen having a support surface that supports the recording medium; a recording medium holding unit that is located downstream of the print head in the transport direction of the recording medium and opposite the support surface, and that holds a plurality of star wheels that are capable of pressing the recording medium toward the support surface in a direction perpendicular to the support surface; a lifting unit that can raise and lower the recording medium holding unit relative to the support surface; and a designation unit that designates an allowable value for the height of the recording medium from the support surface in the direction perpendicular to the support surface when the recording medium passes between the support surface and the recording medium holding unit, and controls the lifting unit so that the force pressing the recording medium per star wheel is 4.5 gf or less when the height of the recording medium from the support surface in the direction perpendicular to the support surface when the recording medium passes between the support surface and the recording medium holding unit is equal to or less than the allowable value. However, the tolerance is the height of the recording medium from the support surface in a direction perpendicular to the support surface, and is the tolerance of the height of the recording medium from the support surface assuming that the recording medium holding portion does not exist. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing the external configuration of a printing apparatus according to a first embodiment. [Diagram 2] FIG. 1 is a schematic diagram showing the internal configuration of a printing apparatus according to a first embodiment. [Diagram 3] FIG. 1 is a partial perspective view showing an internal configuration of a printing apparatus according to a first embodiment. [Figure 4] FIG. 2 is a perspective view showing the configuration of a star wheel unit according to the first embodiment. [Diagram 5] FIG. 2 is a partial cross-sectional view of the star wheel unit according to the first embodiment. [Figure 6] FIG. 2 is a schematic diagram illustrating a state in which continuous paper is transported according to the first embodiment. [Figure 7] FIG. 2 is a front view showing the configuration of the star wheel unit according to the first embodiment. [Figure 8] FIG. 11 is a schematic diagram showing the configuration of a printing apparatus according to a second embodiment. [Figure 9] FIG. 11 is a block diagram showing the control configuration of a printing apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1. First embodiment First, the configuration of the printing device 10 will be described. FIG. 1 is a perspective view showing the external configuration of a printing device 10, and FIG. 2 is a schematic diagram showing the internal structure of the printing device 10. As shown in FIG.

[0009] The printing device 10 is a printer that prints on continuous paper S, such as label paper with labels affixed at regular intervals to a long backing paper, and is also called a label printer. The continuous paper S is an example of a recording medium. The printing device 10 is connected to an information processing terminal via a USB cable, LAN, or the like in a wired or wireless manner, and performs printing based on print data sent from the information processing terminal. USB is an abbreviation for Universal Serial Bus. LAN is an abbreviation for Local Area Network.

[0010] As shown in Fig. 1, the printing device 10 has a case 11 that constitutes the housing of the printing device 10. An operation panel 12 having operation buttons and the like is provided on the +X direction side of the front surface in the +Y direction of the case 11. A slit-shaped paper outlet 13 through which printed continuous paper S is discharged is provided in the center of the front surface of the case 11. On both sides along the X axis of the paper outlet 13, there are provided attachment section covers 14 that cover attachment sections for attaching ink cartridges. The attachment section covers 14 are opened and closed when replacing ink cartridges.

[0011] A cover 15 is provided on the upper surface of the case 11 in the +Z direction. When the cover 15 is moved to the open position and opened, a guide unit 30 provided on the transport path 21 of the continuous paper S is exposed. The cover 15 in this embodiment is rotatable between an open position and a closed position around a hinge (not shown).

[0012] 2, the printing device 10 includes a storage unit 20 that stores roll paper 100, which is continuous paper S wound into a roll, a transport path 21 that runs from the storage unit 20 toward the paper exit 13 of the case 11, and a printing unit 22 that prints on the continuous paper S at a predetermined position on the transport path 21. In this embodiment, a configuration will be described in which roll paper 100 is used as the continuous paper S. Additionally, the direction in which the continuous paper S is transported along the transport path 21 from the storage unit 20 toward the paper exit 13 will be described as the transport direction, and the direction perpendicular to the transport direction will be described as the width direction (direction along the X-axis). It should be noted that the continuous paper S is not limited to label paper, and various types of paper can be used. For example, paper that is folded along perforations provided at intervals in the longitudinal direction, so-called fanfold paper, may be used.

[0013] The storage section 20 is disposed below the cover 15 of the case 11. The paper roll 100 is rotatably supported on the side wall of the storage section 20 via a paper roll rotation shaft .

[0014] A guide unit 30 is disposed in the +Y direction of the storage section 20. The guide unit 30 functions as a paper guide for the continuous paper S. The guide unit 30 includes a guide table 31 capable of supporting the underside of the continuous paper S pulled out of the storage section 20. The guide table 31 includes an upper surface plate 31A that extends in the width direction and is inclined downward as it approaches the front. A side wall-like fixed guide 32 and a movable guide 33 that guide the continuous paper S are supported on the guide table 31. The fixed guide 32 is fixed to the -X direction side of the upper surface plate 31A. The movable guide 33 is supported so as to be slidable in the width direction of the upper surface plate 31A, and is supported so as to be able to move toward and away from the fixed guide 32.

[0015] Fixed guide 32 and movable guide 33 extend in the transport direction of continuous paper S. Fixed guide 32 and movable guide 33 guide the position of the side edges of continuous paper S. Continuous paper S is transported with fixed guide 32 as the position reference.

[0016] In the printing device 10, when adjusting the positions of the guides 32, 33 in accordance with the paper width of the continuous paper S, the position of the movable guide 33 is adjusted with the side edge of the continuous paper S in contact with the fixed guide 32. Therefore, the side edge of the continuous paper S that abuts against the fixed guide 32 is always aligned to the same position in the width direction and transported, regardless of the paper width of the continuous paper S.

[0017] FIG. 3 is a partial perspective view showing the internal structure of the printing device 10. As shown in FIG. The printing device 10 includes a flat bottom frame 24D and side wall-like side frames 24L, 24R erected on both ends of the bottom frame 24D in the direction along the X axis. The bottom frame 24D and the side frames 24L, 24R are covered by a case 11. A paper feed roller 40 is supported by the side frames 24L, 24R. The paper feed roller 40 is provided downstream in the transport direction from the guide unit 30. The paper feed roller 40 includes a drive roller 41 and a driven roller 42 that faces the drive roller 41.

[0018] The driving roller 41 includes a shaft portion 41A extending in the width direction, and a roller portion 41B provided on the shaft portion 41A and having a larger diameter than the shaft portion 41A. The driving roller 41 is rotatably supported by the side frames 24L and 24R. The roller portion 41B is provided on the shaft portion 41A with a gap therebetween in the axial direction.

[0019] The driven roller 42 is disposed above the driving roller 41. The driven roller 42 includes a roller body 42A. The roller body 42A is provided for each roller portion 41B of the driving roller 41, and is disposed opposite the roller portion 41B. The roller body 42A is supported by an arm 43 extending along the Y axis. The roller body 42A is supported at the +Y end of the arm 43 so as to be rotatable about a rotation center extending in the width direction. The arm 43 is supported by the side frames 24L, 24R so as to be rotatable about a rotation center extending in the width direction at the -Y end. The arm 43 is biased by a biasing member (not shown) so as to bias the roller body 42A against the driving roller 41. The driving roller 41 and the driven roller 42 sandwich and transport the continuous paper S.

[0020] A transport motor 46 is supported on the side frame 24L on the +X direction side. The transport motor 46 transmits power to the drive roller 41 via a power transmission member (not shown). The transport motor 46 is configured to be capable of driving forward and backward, and rotates the drive roller 41 forward and backward. When the transport motor 46 is driven, the drive roller 41 is driven. In addition, the driven roller 42 pressed against the drive roller 41 is rotated in accordance with the rotation of the drive roller 41.

[0021] As shown in FIG. 2, the printing unit 22 is disposed downstream of the paper feed roller 40 in the transport direction. The printing unit 22 includes an inkjet head 25 (corresponding to a print head) that ejects ink onto the continuous paper S. The inkjet head 25 is mounted on a carriage 26. The carriage 26 is supported so as to be movable in the width direction along a carriage shaft 27 that extends in the width direction. The carriage 26 is also supported so as to be movable along a guide frame 28 provided within the case 11. The carriage 26 moves along the carriage shaft 27 and the guide frame 28, thereby moving the inkjet head 25 in the main scanning direction (direction along the X-axis).

[0022] The inkjet head 25 has a plurality of nozzle rows corresponding to the four colors of ink, for example, C, M, K. The inkjet head 25 receives a supply of ink from an ink cartridge (not shown) and ejects the ink from nozzles provided in each nozzle row to form dots on the continuous paper S, thereby forming an image.

[0023] As shown in Fig. 3, ink cartridge mounting sections 29L, 29R are provided in the +X and -X directions of the main body of the printing device 10. A pressure pump unit 70 shown in Fig. 2 is connected to the ink cartridges mounted in the ink cartridge mounting sections 29L, 29R via a tube (not shown). The pressure pump unit 70 is driven to pressurize the ink cartridges, and ink is supplied to the inkjet head 25 through an ink flow path (not shown).

[0024] Here, the number of ink colors used by the printing device 10 is not limited to four, and may be configured to print with multiple colors of ink, for example, CMYK and special color inks. The printing device 10 may also be configured to perform monochrome printing or printing with two-color ink.

[0025] A platen 50 is disposed in a position facing the inkjet head 25 in the transport path 21. The platen 50 has a flat support surface 50A on which the continuous paper S is supported. The platen 50 has a suction platen 51 in a position facing the inkjet head 25. The suction platen 51 extends over a range in which dots can be formed by the inkjet head 25. The suction platen 51 has a plurality of suction holes, which communicate with a suction fan 52. The continuous paper S placed on the support surface 50A corresponding to the suction platen 51 is sucked by the suction fan 52. The printing device 10 transports the continuous paper S in a state in which the suction platen 51 is operated, i.e., in a state in which the continuous paper S is sucked, thereby making it possible to transport the continuous paper S without it floating above the suction platen 51. This maintains an appropriate distance between the continuous paper S and the inkjet head 25.

[0026] Of the support surface 50A, the downstream side in the transport direction of the suction platen 51 is a non-suction surface 53 where no suction holes are formed. Therefore, above the non-suction surface 53, a star wheel unit 60 (corresponding to a recording medium pressing unit) for suppressing floating of the continuous paper S is disposed. That is, the star wheel unit 60 is located downstream of the inkjet head 25 in the transport direction and is located at a position facing the non-suction surface 53 of the support surface 50A.

[0027] As shown in Figures 3 and 4, the star wheel unit 60 includes a plurality of star wheels 61. The star wheels 61 have protrusions 61A (see Figure 5) formed on the outer periphery at a constant angular pitch. The star wheels 61 are arranged at intervals in the width direction. The star wheels 61 are configured to be able to press the continuous paper S toward the non-suction surface 53 in a direction perpendicular to the non-suction surface 53. The protrusions 61A of the star wheels 61 come into contact with the continuous paper S while rotating in response to the continuous paper S being transported, so that the contact area with the continuous paper S is small, and the continuous paper S can be transported while reducing deterioration in the quality of the image recorded on the continuous paper S.

[0028] Axles 62 protruding in the width direction are provided at each of the +X direction end and the -X direction end of the star wheel unit 60. In addition, internal frames 63R, 63L that separate the side frames 24L, 24R and the ink cartridge mounting portions 29L, 29R are provided, and the axles 62 of the star wheel unit 60 are supported by the internal frames 63R, 63L.

[0029] As shown in FIG. 5, the star wheel 61 is rotatably supported by a frame 60A of the star wheel unit 60. Specifically, the star wheel 61 rotates around a spring shaft 64 (shaft center 64A) that is made of a compression spring as a rotation axis. The spring shaft 64 is supported in an opening 60B provided in the frame 60A. As a result, when the star wheel 61 presses the continuous paper S, for example, the spring shaft 64 presses the continuous paper S downward while being deformed into a convex shape in the +Z direction. 5, the two star wheels 61 are fixed to each other and supported by the spring shaft 64, but the present invention is not limited to this, and one star wheel 61 may be supported by the spring shaft 64, or three or more star wheels 61 may be supported by the spring shaft 64. The spring shaft 64 has a certain spring constant. The load that each star wheel 61 exerts on the continuous paper S will be described later.

[0030] 2, a cutter unit (not shown) for cutting the continuous paper S can be attached to the downstream side of the suction platen 51 in the transport direction. The cutter unit may be one that cuts the continuous paper S in the width direction, leaving a portion uncut, or one that completely cuts the continuous paper S. In the printing device 10, the cutter unit cuts the continuous paper S printed by the inkjet head 25 to a predetermined length, so that the continuous paper S can be discharged from the paper discharge opening 13.

[0031] Within the case 11 , a transport path 21 along which the continuous paper S is transported from the storage section 20 toward the paper discharge outlet 13 is formed along the guide unit 30 , the paper feed roller 40 , the suction platen 51 , and the paper discharge outlet 13 .

[0032] A guide wall 65 is provided above the guide unit 30 on the downstream side in the transport direction. The guide wall 65 extends in the width direction and is supported by the side frames 24L, 24R. The guide wall 65 extends from above to below, curving more toward the downstream side in the transport direction as it goes downward. The lower end of the guide wall 65 faces the upper plate 31A of the guide unit 30 on the downstream side in the transport direction. In this embodiment, the continuous paper S can be transported to the guide unit 30 along the guide wall 65, and the continuous paper S along the guide wall 65 can be transported by the paper feed roller 40. An upper transport path 65A is formed extending from above along the guide wall 65.

[0033] An optical sensor 71 is disposed between the guide wall 65 and the guide unit 30. The optical sensor 71 is located on the transport path 21 downstream of the upper transport path 65A. The optical sensor 71 is a sensor that detects labels on the continuous paper S, and is a so-called label detector. The optical sensor 71 is composed of a light-emitting unit 71A that emits detection light and a light-receiving unit 71B that receives the detection light. The light-emitting unit 71A is disposed on the guide wall 65, and the light-receiving unit 71B is disposed on the guide unit 30 facing the light-emitting unit 71A. It is also possible that the light-receiving unit 71B is disposed on the guide wall 65, and the light-emitting unit 71A is disposed on the guide unit 30. The optical sensor 71 outputs a detection value according to the amount of light received by the light-receiving unit 71B. The printing device 10 determines the presence or absence of label paper at the position of the optical sensor 71 based on the detection value of the optical sensor 71.

[0034] Next, the regulation of the load with which each star wheel 61 presses the continuous paper S will be described.

[0035] As described above, the star wheel unit 60 is disposed to suppress floating of the continuous paper S on the non-suction surface 53.

[0036] Furthermore, the continuous paper S transported in this embodiment has a curl due to being wound and stacked in a roll shape. Specifically, the continuous paper S that is unwound from the roll paper 100 is curved in an upward convex shape. In addition, in the platen 50, the continuous paper S is conveyed while being sucked by the suction platen 51, so that any curling tendency of the continuous paper S is corrected and the continuous paper S is prevented from lifting off the support surface 50A. Meanwhile, the downstream side of the suction platen 51 in the transport direction is a non-suction surface 53. Therefore, on the non-suction surface 53, the continuous paper S will float from the support surface 50A (non-suction surface 53) due to a curling tendency. If the continuous paper S is transported in a floating state, a jam is likely to occur in the transport path 21. Therefore, a star wheel 61 is disposed above the non-suction surface 53, and by pressing the continuous paper S with the star wheel 61, it is possible to prevent the continuous paper S from floating.

[0037] However, depending on how the star wheel 61 presses down on the label paper (continuous paper S), for example, if the pressure applied by the star wheel 61 to the label paper becomes large, the protrusions 61A of the star wheel 61 may leave marks on the label paper, or adhesive or ink from the label paper may adhere to the tips of the protrusions 61A of the star wheel 61 and be transferred to other parts of the label paper, resulting in a decrease in image quality.

[0038] Therefore, in the printing device 10 of this embodiment, the pressure load of the star wheel 61 on the continuous paper S is specified. Specifically, as shown by the solid line in Figure 6, when the continuous paper S passes between the support surface 50A (non-suction surface 53) and the star wheel unit 60, if the maximum height Hs of the continuous paper S from the support surface 50A in a direction perpendicular to the support surface 50A is less than 2.2 mm, the load with which each star wheel 61 presses the continuous paper S is stipulated to be 4.5 gf or less. However, the maximum value referred to here is the height of the continuous paper S from the support surface 50A in a direction perpendicular to the support surface 50A, and is the maximum height of the continuous paper S from the support surface 50A assuming that the star wheel unit 60 does not exist. In other words, in the printing device 10 of this embodiment, when the continuous paper S passes between the support surface 50A (non-suction surface 53) and the star wheel unit 60, if the maximum height Hs of the continuous paper S from the support surface 50A in a direction perpendicular to the support surface 50A is greater than 2.2 mm, the load applied by each star wheel 61 to the continuous paper S is greater than 4.5 gf. As shown by the two-dot chain line in FIG. 6, the star wheel unit 60 presses the continuous paper S with a load equal to or less than a prescribed value, thereby preventing the continuous paper S from floating above the non-suction surface 53.

[0039] As shown in FIG. 7, the star wheel unit 60 has plate-shaped regulating portions 66 at the +X end and the -X end to regulate the height of the star wheel unit 60. Specifically, the regulating portions 66 have a portion that protrudes from the -Z end of the frame 60A of the star wheel unit 60. A flat regulating surface 66A is provided at the -Z end of the regulating portion 66. The regulating surface 66A comes into contact with the support surface 50A (non-suction surface 53), thereby regulating the height H1 between the support surface 50A (non-suction surface 53) and the shaft center 64A of the star wheel 61 of the star wheel unit 60. The height H1 is a dimension when the star wheel 61 is in a no-load state. Regulating the height H1 allows each star wheel 61 to meet the prescribed load (4.5 gf or less) for pressing the continuous paper S. In this embodiment, when there is no load on the star wheel 61, the clearance between the -Z direction end of the star wheel 61 and the non-suction surface 53 (the gap between the suction platen 51 and the star wheel 61) is set to about 0.6 mm. Therefore, for example, if the maximum height Hs of the transported continuous paper S from the support surface 50A in a direction perpendicular to the support surface 50A is less than 0.6 mm, that is, if there is no contact between the star wheel 61 and the continuous paper S, the load with which each star wheel 61 presses the continuous paper S may be 0 gf.

[0040] 2. Working Example Next, an embodiment will be described.

[0041] 2-1. Examples 1 to 4 and Comparative Examples 1 to 4 Using the printing device 10, the label paper being printed and conveyed was pressed down by the star wheel unit 60 (star wheel 61). The load on the label paper per star wheel 61 is as shown in Table 1. The label paper that was printed and transported was wound around a core tube with a diameter of 3 inches.

[0042] 2-2. Evaluation Content The following image quality evaluation and trace evaluation were carried out.

[0043] 2-3. Image quality evaluation A solid black print was made on label paper, and the presence or absence of image defects (white spots) due to foreign matter (adhesive or ink) attached to the tip of the protrusion 61A of the star wheel 61 was evaluated. The presence or absence of image defects was judged visually.

[0044] 2-3-1.Evaluation criteria A: No defects B: Small amount of damage C: Large amount of damage

[0045] 2-4. Trace evaluation After the label paper was conveyed, the size of the trace of the protrusion 61A of the star wheel 61 formed on the surface of the label paper was measured.

[0046] 2-4-1.Evaluation criteria A: The size of one trace is 3000 μm 2 less than B: The size of one trace is 3000 μm 2 End

[0047] The results are shown in Table 1.

[0048] [Table 1]

[0049] As shown in Table 1, when the load applied to the label paper per star wheel 61 was 4.5 gf or less (Examples 1 to 4), the image quality evaluation and the trace evaluation showed excellent results. On the other hand, when the load applied to the label paper per star wheel 61 exceeded 4.5 fg (Comparative Examples 1 to 4), it was found that the results were inferior in all evaluations compared to Examples 1 to 4.

[0050] As described above, according to this embodiment, even when using continuous paper S that has a curling tendency when it was wound around a core tube, the load that presses the continuous paper S per star wheel 61 is adjusted, so that, for example, when the continuous paper S is label paper, adhesion of adhesive and ink to the tip of the protrusion 61A of the star wheel 61 and the occurrence of traces caused by the protrusion 61A of the star wheel 61 on the continuous paper S are suppressed, thereby improving image quality.

[0051] 3. Second embodiment Next, a second embodiment will be described. Specifically, the configuration and control method of the printing device 10A will be described. More specifically, the lifting mechanism and control method of the star wheel unit 600 will be described. Note that the configuration other than the lifting control mechanism of the star wheel unit 600 is the same as that of the first embodiment, and the same reference numerals are used for the same configuration as the first embodiment, and duplicated explanations will be omitted.

[0052] Fig. 8 is a schematic diagram showing the configuration of the printing device 10A according to this embodiment, and in particular, a schematic diagram showing the configuration around the star wheel unit 600. Fig. 9 is a block diagram showing the control configuration of the printing device 10A, specifically, a block diagram showing the configuration for lifting and lowering the star wheel unit 600.

[0053] As shown in FIG. 8, the printing apparatus 10A includes a lifting section 700 that can raise and lower the star wheel unit 600 relative to the support surface 50A (non-suction surface 53). Elevating section 700 includes ball screw shaft 701 erected in a direction along the Z axis, a ball nut 711 engaged with ball screw shaft 701, and a guide section (not shown) that guides ball nut 711 in a moving direction. A motor 712 is connected to ball screw shaft 701. As motor 712, various motors such as a stepping motor, a servo motor, and a linear motor can be used. Driving motor 712 enables ball nut 711 to move up and down in a direction along the Z axis.

[0054] The shaft portion 62 of the star wheel unit 600 is fixed to a ball nut 711. This allows the star wheel unit 600 to move up and down. The lifting unit 700 also includes a rotary encoder 713 that detects the direction and amount of rotation of the motor 712 or the ball screw shaft 701. This makes it possible to detect the amount of movement (position) of the star wheel unit 600. In this embodiment, the height Ht between the support surface 50A (non-suction surface 53) and the shaft center 64A of the star wheel 61 is detectable. The lifting mechanism of the star wheel unit 600 may be configured using a cam or a solenoid instead of the above configuration.

[0055] The printing device 10A also has a designation unit that designates the tolerance of the height of the continuous paper S from the support surface 50A in a direction perpendicular to the support surface 50A when the continuous paper S passes between the support surface 50A and the star wheel unit 600. However, the tolerance referred to here is the height of the continuous paper S from the support surface 50A in a direction perpendicular to the support surface 50A, and is the tolerance of the height of the continuous paper S from the support surface 50A when it is assumed that the star wheel unit 600 does not exist. The printing device 10A can accommodate multiple types of continuous paper S. Here, the height from the support surface 50A in the direction perpendicular to the support surface 50A may differ depending on each type of continuous paper S. For example, continuous paper S wound around a core tube with a diameter of φ3 inches and continuous paper S wound around a core tube with a diameter of φ6 inches have different curling patterns, and therefore have different heights from the support surface 50A in the direction perpendicular to the support surface 50A. In this case, the continuous paper S wound around a core tube with a diameter of φ3 inches has a stronger curling pattern and is therefore higher above the support surface 50A. Therefore, the designation unit designates the tolerance for each continuous paper S. The designation unit may be configured, for example, to designate the height tolerance via operation panel 12, or may be configured such that the height tolerance is designated in control unit 800 based on input information related to the continuous paper S from operation panel 12 or an information processing terminal. In addition, the tolerance for the continuous paper S may be specified taking into consideration parameters other than the curling tendency, such as the diameter size of the core tube, the material and thickness of the continuous paper S, etc.

[0056] 9, the control unit 800 has a CPU 801, a memory 802, a control circuit 803, and an I / F (interface) 804. The CPU 801 is an arithmetic processing device. The memory 802 is a storage device that secures an area for storing programs of the CPU 801 or a working area, and has storage elements such as a RAM and an EEPROM. When print data or the like is acquired from an external device such as an information processing terminal via the I / F 804, the CPU 801 controls each driving unit (motor 712) and the like.

[0057] The memory 802 stores table data that corresponds to the tolerance for each continuous paper S and the height position at which the load with which each star wheel 61 presses the continuous paper S is 4.5 gf or less.

[0058] When the control unit 800 determines that the height of the continuous paper S from the support surface 50A in a direction perpendicular to the support surface 50A is below an allowable value when the continuous paper S passes between the support surface 50A (non-suction surface 53) and the star wheel unit 600, it drives the motor 712 and controls the lifting unit 700 to move to a specified position so that the load applied by each star wheel 61 to press the continuous paper S is 4.5 gf or less. It should be noted that when the control unit 800 determines that the height of the continuous paper S from the support surface 50A in a direction perpendicular to the support surface 50A is greater than the allowable value, it stops driving the transport of the continuous paper S.

[0059] According to this embodiment, the star wheel unit 60 can be moved vertically according to the allowable value for the height of the continuous paper S due to its curling tendency on the support surface 50A, and the continuous paper S can be pressed down with an appropriate load. [Explanation of symbols]

[0060] 10, 10A...printing device, 12...operation panel, 21...transport path, 22...printing section, 25...inkjet head, 26...carriage, 50...platen, 50A...support surface, 51...suction platen, 53...non-suction surface, 60...star wheel unit, 60A...frame, 60B...opening, 61...star wheel, 61A...projection, 62...shaft portion, 63L...internal frame, 63R...internal frame, 64...spring shaft , 64A...axis center, 65...guide wall, 65A...upper conveying path, 66...regulating section, 66A...regulating surface, 100...roll paper, 600...star wheel unit, 700...lifting section, 701...ball screw shaft, 711...ball nut, 712...motor, 713...rotary encoder, 800...control section, 801...CPU, 802...memory, 803...control circuit, 804...interface, S...continuous paper.

Claims

1. A print head that ejects ink onto a recording medium to form an image; a platen having a support surface for supporting the recording medium; a recording medium pressing unit that is located downstream of the print head in the conveying direction of the recording medium and that is located opposite the support surface and that holds a plurality of star wheels that can press the recording medium toward the support surface in a direction perpendicular to the support surface; a lifting unit that can lift and lower the recording medium pressing unit relative to the support surface; a designation unit that designates a tolerable value of a height of the recording medium from the support surface in a direction perpendicular to the support surface when the recording medium passes between the support surface and the recording medium pressing unit, assuming that the recording medium pressing unit is not present; A control unit, a control unit that controls the lift unit so that the force that holds down the recording medium per one star wheel is 4.5 gf or less when the height of the recording medium from the support surface in a direction perpendicular to the support surface is equal to or less than the allowable value when the recording medium passes between the support surface and the recording medium pressing unit, where the allowable value is the height of the recording medium from the support surface in a direction perpendicular to the support surface, and is the allowable value of the height of the recording medium from the support surface assuming that the recording medium pressing unit does not exist.

2. a recording medium pressing unit that is located downstream of the print head in a transport direction of the recording medium and facing the support surface, the recording medium pressing unit holding a plurality of star wheels that can press the recording medium toward the support surface in a direction perpendicular to the support surface; an elevation unit that can raise and lower the recording medium pressing unit relative to the support surface; and a designation unit that designates an allowable value for a height of the recording medium from the support surface in a direction perpendicular to the support surface when the recording medium passes between the support surface and the recording medium pressing unit, assuming that the recording medium pressing unit is not present, A control method for a printing device, comprising: controlling the lifting unit so that the force pressing the recording medium per one star wheel is 4.5 gf or less when the height of the recording medium from the support surface in a direction perpendicular to the support surface is equal to or less than the allowable value when the recording medium passes between the support surface and the recording medium pressing unit, wherein the allowable value is the height of the recording medium from the support surface in a direction perpendicular to the support surface, and is the allowable value of the height of the recording medium from the support surface assuming that the recording medium pressing unit does not exist.

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