Inkjet printer

Abstract

Provided is an inkjet printer capable of suppressing a reduction in printing quality of a medium caused by floating of the medium and deviation of a head gap, and capable of reducing the manufacturing cost of a platen. In the inkjet printer, a suction hole group (15b) including a large number of suction holes (15a) for sucking a medium placed on a platen (15) and arranged in a main scanning direction is formed in the platen (15), and a plurality of suction holes (15b) for sucking the medium placed on the platen (15) are formed in the portion of the platen (15) where the suction hole group (15b) is formed. A linear groove (15c) which is recessed from the upper surface of the platen (15) and extends in the main scanning direction is formed. Only linear grooves (15c) are formed on the upper surface of the platen (15) as grooves for sucking the medium.

Description

Technical Field

[0001] This invention relates to an inkjet printer for printing on media. Background Technology

[0002] Previously, inkjet printers for printing on elongated media were known (for example, see Patent Document 1). The inkjet printer described in Patent Document 1 includes: an ink head for ejecting ink onto the media; a carriage for mounting the ink head; a head moving mechanism for moving the carriage in the main scanning direction; a platen (support) for holding the printing media; and an adsorption device for adsorbing the media placed on the platen onto the platen. The upper surface of the platen is a planar support surface for supporting the media.

[0003] In the inkjet printer described in Patent Document 1, a first to a fifth groove recessed downwards are formed on the support surface of the printing platen. The first to fifth grooves are straight grooves extending along the main scanning direction. Numerous suction holes for drawing media are formed in the first to fifth grooves. In this inkjet printer, the first and second grooves are arranged in the sub-scanning direction. Multiple connecting grooves are formed on the support surface to connect the first and second grooves. These connecting grooves are straight grooves inclined relative to both the main and sub-scanning directions.

[0004] In the inkjet printer described in Patent Document 1, suction holes are formed in the first to fifth slots, which are long, straight lines along the main scanning direction. These suction holes are less prone to clogging by the media placed on the support surface. Therefore, in this inkjet printer, the first to fifth slots are used as a whole to suction the media. Furthermore, in this inkjet printer, the media is suctioned via a connecting groove formed between the first and second slots. Therefore, in this inkjet printer, the floating of the media placed on the platen can be suppressed, and as a result, the degradation of print quality caused by media floating can be suppressed.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-160826 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] On the other hand, in the inkjet printer described in Patent Document 1, since a connecting groove is formed between the first groove and the second groove, the distance between the portion of the medium placed on the platen between the first groove and the second groove and the lower surface of the inkjet head that ejects ink may deviate. That is, in the inkjet printer, the head gap may deviate between the first groove and the second groove.

[0010] Therefore, in the inkjet printer described in Patent Document 1, even if the decline in print quality caused by media buoyancy can be suppressed, the print quality may still decrease due to the deviation in the head gap between the first and second slots. Furthermore, in the inkjet printer described in Patent Document 1, since multiple connecting slots inclined relative to the main scanning direction and the sub-scanning direction are formed between the first and second slots, the manufacturing cost of the printing platen may increase.

[0011] Therefore, the objective of this invention is to provide an inkjet printer that can suppress the decline in print quality of the media caused by media buoyancy and head gap deviation, and can reduce the manufacturing cost of the printing platen.

[0012] Technical means to solve the problem

[0013] To solve the aforementioned problem, the inkjet printer of the present invention is characterized by comprising: an inkjet head for ejecting ink onto a medium; a printing platen disposed below the inkjet head and holding the medium for printing; and a suction mechanism for suctioning the medium placed on the printing platen onto the printing platen. The printing platen has a group of suction holes comprising a large number of suction holes for suctioning the medium placed on the printing platen and arranged in the main scanning direction, which is the width direction of the medium. In the portion of the printing platen forming the group of suction holes, a straight groove is formed that is recessed from the upper surface of the printing platen and extends along the main scanning direction. Only the straight groove is formed on the printing platen as a groove recessed from the upper surface of the printing platen.

[0014] In the inkjet printer of the present invention, a straight groove extending along the main scanning direction is formed in the portion of the platen where the suction hole group is formed, making the suction holes less prone to clogging by the media placed on the platen. Therefore, in the present invention, the media can be suctioned using the entire straight groove. Thus, in the present invention, the floating of the media placed on the platen can be suppressed, and consequently, the degradation of print quality caused by media floating can be suppressed. Furthermore, in the present invention, only the straight groove is formed in the platen as a groove recessed from the upper surface of the platen, thus avoiding the head gap deviation between the first and second grooves as described in Patent Document 1. Therefore, in the present invention, the degradation of print quality caused by head gap deviation can be suppressed.

[0015] Furthermore, in this invention, only straight grooves are formed on the printing platen as grooves recessed from the upper surface of the printing platen. Therefore, compared to the case where multiple connecting grooves are formed between the first and second grooves in an inkjet printer as described in Patent Document 1, the manufacturing cost of the printing platen can be reduced. Thus, in this invention, the decline in print quality of the media caused by media floating can be suppressed, the decline in print quality of the media caused by head gap deviation can be suppressed, and the manufacturing cost of the printing platen can be reduced.

[0016] Furthermore, when the heater for heating the medium is built into the platen, if multiple connecting grooves are formed between the first and second grooves as in the inkjet printer described in Patent Document 1, the medium does not contact the platen in the areas where the connecting grooves are formed, making it difficult to achieve a uniform temperature distribution of the heated medium. In contrast, in this invention, compared to the case where multiple connecting grooves are formed between the first and second grooves, it is easier to achieve a uniform temperature distribution of the heated medium.

[0017] In this invention, the inkjet printer includes, for example, a heater for heating the medium before printing. According to the inventors' research, when the medium is heated before printing, it tends to stretch depending on its thickness or type, and thus the medium placed on the printing platen tends to float. However, in this invention, even when the medium is heated before printing, the floating of the medium placed on the printing platen can be suppressed.

[0018] In this invention, for example, the stage has four groups of suction holes and four straight grooves arranged at intervals in a sub-scanning direction orthogonal to the vertical direction and the main scanning direction. Furthermore, in this invention, for example, the depth of the straight grooves is 0.3 mm or less.

[0019] The effects of the invention

[0020] As described above, in the inkjet printer of the present invention, the decline in printing quality of the media caused by media floating and head gap deviation can be suppressed, and the manufacturing cost of the printing plate can be reduced. Attached Figure Description

[0021] [ Figure 1 [Illustration 1] is a side view illustrating the structure of an inkjet printer according to an embodiment of the present invention.

[0022] [ Figure 2 ]yes Figure 1 The diagram shows a three-dimensional view of the platform.

[0023] [ Figure 3 ]yes Figure 2 A plan view of a portion of the platform shown.

[0024] [ Figure 4 ]yes Figure 2 The table shown is a side view.

[0025] [ Figure 5 ]yes Figure 4 An enlarged view of part E. Detailed Implementation

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0027] (The overall structure of an inkjet printer)

[0028] Figure 1 This is a side view illustrating the structure of an inkjet printer 1 according to an embodiment of the present invention.

[0029] The inkjet printer 1 (hereinafter referred to as "printer 1") in this embodiment is, for example, an inkjet printer for business use. Printer 1 includes: a printing mechanism 3 for printing on a strip of medium 2 (sheet-shaped medium 2) such as paper, cloth or resin sheet; a medium conveying mechanism 4 for conveying the medium 2; an ejector roll holding part 6 for holding the medium 2 wound into a roll before printing, i.e., ejector roll 5; a take-up roll holding part 8 for holding the printed medium 2 wound into a roll, i.e., take-up roll 7; and a heater 9 for heating the medium 2 before printing.

[0030] When perpendicular to the vertical direction Figure 1 When the Y-direction is set to "left-right direction", the width direction of medium 2 is consistent with the left-right direction. In the following description, the direction orthogonal to the up-down and left-right directions will be used. Figure 1 The X direction is set as the "front-back direction". Additionally, one side of the front-back direction... Figure 1 The X1 direction side is designated as the "front" side, and its opposite side is... Figure 1 The X2 direction side is designated as the "rear" side. In this embodiment, the left-right direction (Y direction) is the main scanning direction, and the front-back direction (X direction) is the secondary scanning direction.

[0031] The printing mechanism 3 includes: an inkjet head 12 (hereinafter referred to as "head 12") for ejecting ink onto the medium 2; a carriage 13 for mounting the head 12; a carriage drive mechanism for reciprocating the carriage 13 in the main scanning direction (left-right direction); and a support frame (Y-shaped rod) 14 for supporting the carriage 13 to allow for left-right movement. The head 12 ejects ink downwards. A plurality of nozzles for ejecting ink are formed on the lower surface of the head 12. The head 12 includes a piezoelectric element for ejecting ink from the nozzles. The carriage drive mechanism includes, for example, a belt, partially fixed to the carriage 13; a pulley for mounting the belt; and a motor for rotating the pulley.

[0032] In this embodiment, the ink ejected from head 12 is an ultraviolet (UV) ink that cures with ultraviolet light. A UV irradiator (not shown) is mounted on carriage 13, which irradiates ultraviolet light onto the medium 2 to cure the UV ink ejected from head 12. The UV irradiator includes a light-emitting diode (LED) chip. Additionally, an ink heating mechanism (not shown) is mounted on carriage 13 to heat the UV ink, thereby reducing its viscosity. The ink heating mechanism heats the UV ink supplied to head 12.

[0033] Additionally, the printing mechanism 3 includes: a printing plate 15 for holding the printing medium 2; a printing plate frame 16 for supporting the printing plate 15 from below; and a suction mechanism 17 for suctioning the medium 2 placed on the printing plate 15. The printing plate 15 is located below the head 12 and the carriage 13. The printing plate 15 is formed into an elongated strip in the left-right direction. Numerous suction holes 15a (see reference) are formed on the printing plate 15 for suctioning the medium 2 placed on the printing plate 15. Figure 3 The suction holes 15a penetrate the platen 15 in the vertical direction. The suction holes 15a are formed extensively throughout almost the entire area of ​​the platen 15. The thickness direction of the medium 2 during printing using the printing mechanism 3 is consistent with the vertical direction. The specific structure of the platen 15 will be described later.

[0034] The platform frame 16 is formed into a slender square groove (quadrilateral groove) in the left-right direction. The platform frame 16 is formed by bending a thin sheet of metal, such as steel, into a square groove shape. The upper surface of the platform frame 16 is open. The platform 15 is fixed to the upper end of the platform frame 16, and the upper surface of the platform frame 16 is blocked by the platform 15. Inside the platform frame 16, a space defined by the platform frame 16 and the platform 15 is formed. The suction hole 15a communicates with this space.

[0035] The suction mechanism 17 includes a plurality of suction fans 18 disposed on the underside of the table frame 16. The suction fans 18 are fixed to the bottom surface of the table frame 16. The suction fans 18 draw air from the space defined by the table frame 16 and the table 15. That is, when the suction fans 18 operate, the air inside the space defined by the table frame 16 and the table 15 is expelled. When the air inside the space defined by the table frame 16 and the table 15 is expelled, the medium 2 is drawn to the upper surface of the table 15, thereby holding the medium 2 using the table 15. The suction fans 18 operate during the printing of the medium 2.

[0036] The media conveying mechanism 4 conveys a strip of media 2 along its long side. The media conveying mechanism 4 includes a conveying roller 19 and a pad roller 20 disposed opposite to the conveying roller 19 and applying force towards it. The conveying roller 19 and the pad roller 20 are disposed on the rear side of the table 15. The conveying roller 19 is connected to a drive mechanism that rotates the conveying roller 19. The drive mechanism includes a motor as the drive source. The media 2 is conveyed while being sandwiched between the conveying roller 19 and the pad roller 20. Before printing, the media 2 is conveyed from the rear side to the upper surface of the table 15; after printing, the media 2 is conveyed from the upper surface of the table 15 to the front side.

[0037] The pull-out roll holding part 6 is disposed on the lower side of the printing mechanism 3. The pull-out roll holding part 6 includes a rotating shaft 23 that passes through the inner circumference of the pull-out roll 5. The take-up roll holding part 8 is disposed on the lower side of the printing mechanism 3. The take-up roll holding part 8 includes: a rotating shaft 24 that passes through the inner circumference of the take-up roll 7; and a drive mechanism that rotates the rotating shaft 24. A heater 9 is disposed between the transport roller 19 and the pad roller 20 and the pull-out roll holding part 6 in the transport direction of the medium 2. The heater 9 is covered by a cover. The heater 9 heats the medium 2 that moves toward the table 15.

[0038] (Structure of the platform)

[0039] Figure 2 yes Figure 1 A perspective view of the platform 15 shown. Figure 3 yes Figure 2 A plan view of a portion of the platform 15 shown. Figure 4 yes Figure 2 The side view of the platform 15 shown. Figure 5 yes Figure 4 An enlarged view of part E.

[0040] As described above, the stage 15 is formed as an elongated strip in the left-right direction. The upper surface of the stage 15 serves as the medium placement surface for the medium 2. As described above, a large number of suction holes 15a are formed in the stage 15, penetrating the stage 15 in the vertical direction. In addition, a group of suction holes 15b, which includes the large number of suction holes 15a arranged in the left-right direction, is formed in the stage 15. In this embodiment, four groups of suction holes 15b are formed in the stage 15, arranged at intervals in the front-back direction (sub-scanning direction). Two of the four groups of suction holes 15b are arranged adjacent to each other at a position further forward of the center of the stage 15 in the front-back direction, and the remaining two groups of suction holes 15b are arranged adjacent to each other at a position further backward of the center of the stage 15 in the front-back direction.

[0041] In the portion of the platform 15 where the suction hole group 15b is formed, a straight groove 15c is formed that is recessed from the upper surface of the platform 15 toward the lower side and extends in the left-right direction. That is, the suction hole group 15b is formed in the straight groove 15c. As described above, in this embodiment, four suction hole groups 15b are formed on the platform 15 in a spaced-apart manner in the front-back direction, and four straight grooves 15c are formed on the platform 15 in a spaced-apart manner in the front-back direction. That is, straight grooves 15c are formed in all portions of the platform 15 where the suction hole group 15b is formed. Figure 3 The portion with the shadow line applied is the straight groove 15c. The straight groove 15c is a groove that extends from the left end to the right end of the platform 15 in the left-right direction. That is, the straight groove 15c is formed over the entire area of ​​the platform 15 in the left-right direction.

[0042] The straight groove 15c is formed as a shallow square groove (quadrilateral groove). The suction hole 15a is formed, for example, at the center of the straight groove 15c in the front-to-back direction. The width of the straight groove 15c (width in the front-to-back direction) is larger than the inner diameter of the suction hole 15a. For example, the width of the straight groove 15c is approximately five times the inner diameter of the suction hole 15a. The depth D of the straight groove 15c (specifically, the depth D of the straight groove 15c from the upper surface of the platform 15, refer to...) Figure 5 The thickness is less than 0.3 mm. Only four straight grooves 15c are formed on the platform 15 as grooves recessed from the upper surface of the platform 15. That is, only straight grooves 15c are formed on the upper surface of the platform 15 as grooves for suction of the medium.

[0043] (The main effects of this implementation method)

[0044] As explained above, in this embodiment, a straight groove 15c extending in the left-right direction is formed in the portion of the platen 15 where the suction hole group 15b is formed, making it less likely for the suction holes 15a to be blocked by the medium 2 placed on the platen 15. Therefore, in this embodiment, the medium 2 can be suctioned using the straight groove 15c as a whole. Therefore, in this embodiment, the floating of the medium 2 placed on the platen 15 can be suppressed, and as a result, the degradation of the printing quality of the medium 2 caused by the floating of the medium 2 can be suppressed.

[0045] Furthermore, in this embodiment, since the medium 2 before printing is heated by the heater 9, the medium 2 is prone to stretching depending on its thickness or type, and the medium 2 placed on the platen 15 is prone to floating. However, in this embodiment, even if the medium 2 before printing is heated, the floating of the medium 2 placed on the platen 15 can be suppressed.

[0046] Furthermore, according to the inventors' research, in this embodiment, the UV ink ejected from head 12 is heated by the ink heating mechanism, and reaction heat is generated in the UV ink ejected onto the medium 2. Additionally, the substrate of the UV LED chip heats up when the medium 2 is irradiated with ultraviolet light. Therefore, the medium 2 placed on the platform 15 is heated due to these factors, and depending on the thickness or type of the medium 2, it tends to stretch, making it prone to floating. Furthermore, according to the inventors' research, when using a thin, inelastic, easily bent, and weakly tough medium 2, when the medium 2 is formed of vinyl chloride, or when the ambient temperature of the printer 1 is low, the medium 2 placed on the platform 15 tends to float. However, in this embodiment, the floating of the medium 2 placed on the platform 15 can be suppressed.

[0047] In this embodiment, only a straight groove 15c is formed on the platen 15 as a groove recessed from the upper surface of the platen 15. Therefore, in this embodiment, unlike the inkjet printer described in Patent Document 1, there is no deviation in the head gap between the first and second grooves. Therefore, in this embodiment, the degradation of the printing quality of the medium 2 caused by the deviation in the head gap can be suppressed. In addition, in this embodiment, since only a straight groove 15c is formed on the platen 15 as a groove recessed from the upper surface of the platen 15, the manufacturing cost of the platen 15 can be reduced compared to the case where multiple connecting grooves are formed between the first and second grooves as in the inkjet printer described in Patent Document 1.

[0048] (Other implementation methods)

[0049] The described embodiment is an example of a suitable embodiment of the present invention, but is not limited thereto, and various modifications can be made without changing the spirit of the present invention.

[0050] In this embodiment, the straight groove 15c may not be formed over the entire area of ​​the platen 15 in the left-right direction. Furthermore, in this embodiment, the depth D of the straight groove 15c may be deeper than 0.3 (mm). Moreover, in this embodiment, two or three suction hole groups 15b arranged at intervals in the front-back direction may be formed on the platen 15, or five or more suction hole groups 15b may be formed on the platen 15. In this case, the number of straight grooves 15c is the same as the number of suction hole groups 15b. Additionally, in this embodiment, the printer 1 may include a heater for heating the printed medium 2. Alternatively, the printer 1 may not include a heater 9.

[0051] Explanation of icon numbers

[0052] 1: Printer (Inkjet Printer)

[0053] 2: Medium

[0054] 9: Heater

[0055] 12: Head (Inkjet Head)

[0056] 15: Table

[0057] 15a: Suction hole

[0058] 15b: Suction port group

[0059] 15c: Straight groove

[0060] 17: Suction Mechanism

[0061] D: Depth of the straight groove

[0062] X: Sub-scanning direction

[0063] Y: Main scanning direction

Claims

1. An inkjet printer, characterized in that... include: The inkjet head ejects ink onto the medium; A printing plate is disposed on the underside of the inkjet head and holds the printing medium. And a suction mechanism for suctioning the medium placed on the platform onto the platform. The stage has a group of suction holes containing a large number of suction holes. These suction holes are used to suction the medium placed on the stage and are arranged in the main scanning direction, which is the width direction of the medium. In the portion of the platform that forms the suction hole group, a straight groove is formed that is recessed from the upper surface of the platform and extends along the main scanning direction. On the upper surface of the platform, only the straight groove is formed as a groove for sucking up the medium.

2. The inkjet printer according to claim 1, characterized in that: Includes a heater for heating the medium prior to printing.

3. The inkjet printer according to claim 1 or 2, characterized in that: The platform has four groups of suction holes and four straight grooves arranged at intervals in a sub-scanning direction orthogonal to the vertical direction and the main scanning direction.

4. The inkjet printer according to claim 1 or 2, characterized in that: The depth of the straight groove is less than 0.3 mm.

Images