A device for dispensing liquid

Abstract

This suppresses adhesion between the discharged medium and the medium holding surface, thereby reducing downtime caused by such adhesion. [Solution] A liquid dispensing device comprising a transport unit 20 that transports a medium to be dispensed 30 while in contact with a medium holding surface 5a, and a liquid dispensing unit 10 that dispenses liquid onto the medium to be dispensed held on the medium holding surface, wherein the liquid dispensing operation is performed when the transport of the medium to be dispensed is stopped, and further comprising a protruding part 53 that protrudes from the medium holding surface, a switching unit 50 that switches between a protruding state in which the protruding part protrudes from the medium holding surface and a retracted state in which it is retracted from the medium holding surface, and a control unit that controls the switching unit so that it takes the protruding state during the transport of the medium to be dispensed and the retracted state during the liquid dispensing operation.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for ejecting liquid. [Background Art]

[0002] Conventionally, there has been known a liquid ejecting apparatus that includes: a conveying section that conveys an ejection target medium while keeping the medium in contact with a medium holding surface; and a liquid ejecting section that ejects liquid onto the ejection target medium held at a predetermined position on the medium holding surface, wherein the liquid ejecting operation is performed while conveyance of the ejection target medium is stopped.

[0003] For example, Patent Document 1 discloses a printer (liquid ejecting apparatus) that includes a platen for maintaining a predetermined distance (gap) between a print head and a sheet, and conveys the sheet (ejection target medium) by a conveying roller arranged on the upstream side of the platen in the conveying direction while keeping the sheet in contact with the upper surface (medium holding surface) of the platen. This printer performs printing on the sheet by alternately repeating sheet conveyance and liquid ejection by the print head (liquid ejecting head). In this printer, in order to obtain higher-quality images, a plurality of suction holes are formed in the upper surface of the platen, and printing is performed while suctioning the sheet to bring it into close contact with the upper surface of the platen. When the sheet sticks to the platen and the portion of the sheet fed by the conveying roller sags between the platen and the conveying roller, the conveying roller is rotated in reverse to eliminate the slack in the sheet. Then, after the slack is eliminated, the conveying roller is further rotated reversely, thereby peeling off the sheet stuck to the platen and eliminating the sticking between the platen and the sheet. [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, in conventional apparatuses, if the ejection target medium sticks to the medium holding surface that is used to maintain a predetermined distance (gap) between the liquid ejecting head and the ejection target medium, it takes time to perform processing for eliminating the sticking, resulting in a problem that downtime occurs. [Means for Solving the Problem]

[0005] To solve the above-mentioned problems, the present invention provides a liquid dispensing device comprising: a transport unit that transports a medium to be dispensed while in contact with a medium holding surface; and a liquid dispensing unit that dispenses liquid onto the medium to be dispensed held at a predetermined location on the medium holding surface, wherein the liquid dispensing operation is performed while the transport of the medium to be dispensed is stopped, and the device further comprises: a protruding part that protrudes from the medium holding surface; a switching unit that switches between a protruding state in which the protruding part protrudes from the medium holding surface and a retracted state in which the protruding part is retracted from the medium holding surface; and a control unit that controls the switching unit so that the protruding state is taken during the transport of the medium to be dispensed and the retracted state is taken during the liquid dispensing operation. [Effects of the Invention]

[0006] According to the present invention, it is possible to suppress the adhesion of the discharged medium to the medium holding surface, which maintains a predetermined distance (gap) between the liquid discharge head and the discharged medium, thereby suppressing the occurrence of downtime caused by such adhesion. [Brief explanation of the drawing]

[0007] [Figure 1] A diagram showing an overview of the inkjet recording device in an embodiment. [Figure 2] This is an explanatory diagram showing the basic configuration of the platen unit installed in the inkjet recording device. [Figure 3] This diagram illustrates how, in a conventional device, the portion of the roll paper upstream in the roll paper transport direction where the roll paper is stuck lifts away from the guide surface of the platen. [Figure 4] An exploded perspective view showing the projection movement mechanism of the embodiment together with the platen. [Figure 5] A flowchart illustrating the printing process in the embodiment. [Figure 6] This diagram illustrates how the protrusion of the protruding part movement mechanism causes the portion of the roll paper passing over the protruding part during roll paper transport to lift away from the guide surface of the platen. [Figure 7]This diagram illustrates how the roll paper portion passing above the retracted protrusion during liquid dispensing does not lift off the guide surface of the platen. [Modes for carrying out the invention]

[0008] The following describes one embodiment in which the present invention is applied to an inkjet recording apparatus, which is an image forming apparatus that ejects liquid. However, the present invention is not limited to the embodiments exemplified below.

[0009] First, the basic configuration of the inkjet recording device 100 according to this embodiment will be described. Figure 1 is a schematic diagram showing the overview of the inkjet recording apparatus in this embodiment. Figure 2 is an explanatory diagram showing the basic configuration of the platen unit 40 provided in the inkjet recording device of this embodiment. The inkjet recording apparatus 100 according to this embodiment is a serial type apparatus and includes a transport device 20 as a transport unit for transporting the roll paper 30 which is the ejection medium, and a liquid ejection unit 10 as a liquid ejection unit.

[0010] The liquid ejection unit 10 is equipped with a liquid ejection head 12 that ejects liquid ink, a carriage 11 that is arranged to move back and forth in the main scanning direction (a direction perpendicular to the transport direction of the roll paper 30 (the width direction of the roll paper 30)), and an ink tank that contains ink.

[0011] The transport device 20 includes a paper feed device 2 that holds the roll paper 30 before image formation, and a winding device 7 that winds up the roll paper 30 after image formation. A paper feed guide plate 3 is also positioned upstream of the liquid discharge head 12 in the roll paper transport direction to guide the roll paper 30 as it is transported toward the liquid discharge head 12. In addition, a pair of transport rollers (transport roller 4a, pressure roller 4b) are positioned as transport members that apply transport force to the roll paper 30.

[0012] Opposite the liquid discharge head 12 is a platen unit 40 for holding the roll paper 30. The platen unit 40 has a platen 5 with a plurality of suction holes 5b (see Figure 2) formed on its upper surface (guide surface) 5a, which serves as the media holding surface, and a suction device 8 that acts as an adsorption part to suck the roll paper 30 from the suction holes 5b of the platen 5 and adsorb the roll paper onto the platen 5. Furthermore, a paper discharge guide plate 6 is positioned downstream of the liquid discharge head 12 in the roll paper transport direction to guide the roll paper on which the image has been formed.

[0013] The roll paper 30 fed from the paper feed device 2 passes over the paper feed guide plate 3 and is held between the transport roller 4a and the pressure roller 4b. The roll paper 30, transported by the transport roller 4a, reaches the guide surface 5a of the platen 5 facing the liquid discharge head 12, where it undergoes image formation processing with ink discharged from the liquid discharge head 12.

[0014] In the image forming process, the roll paper 30 is intermittently transported by the transport roller 4a to form an image on the roll paper 30. Specifically, with the roll paper 30 held in place by the suction device 8 on the guide surface 5a of the platen 5, the carriage 11 is moved in the main scanning direction, and liquid is discharged from the liquid discharge head 12 on the carriage 11 according to the image information (print information). After that, the transport roller 4a transports a predetermined amount of the roll paper 30, then the roll paper 30 is held in place by the suction device 8 on the guide surface 5a of the platen 5, and liquid is discharged onto the roll paper 30 by the liquid discharge head 12 on the carriage 11. The roll paper 30 with the image formed on it is guided by the paper discharge guide plate 6 and wound onto the winding device 7.

[0015] Various materials such as resins and metals are used for the platen 5, and similarly, various types of roll paper are used, including plain paper, coated paper, PVC, and PET. For example, if the platen 5 is made of aluminum, when plain paper is transported, the triboelectric series of aluminum and paper are close, so triboelectric charging due to friction with the platen 5 is unlikely to occur. However, if the roll paper 30 is made of PET, the triboelectric series of aluminum and polyethylene are far apart, so triboelectric charging between the platen 5 and the roll paper 30 is more likely to occur.

[0016] In recent years, a new printing method for apparel called DTF (Direct to Film) has been attracting attention. In DTF, for example, a desired color image is printed on a film medium, and then a white background image is printed on top of it. Then, a powder called hot melt powder is applied to this film medium and dried, and the powdered surface is then applied to the fabric to transfer the image from the film medium to the fabric. The film medium used here is often a thin PET film with a thickness of 0.05 mm to 0.15 mm and low stiffness. Therefore, in the case of roll paper 30 made of such film medium, triboelectric charging with the platen 5 is likely to occur.

[0017] In particular, fluctuations in the distance (gap) between the roll paper 30 and the liquid discharge head 12 (deviation from the specified distance (specified gap)) greatly affect image quality. Therefore, the guide surface 5a (media holding surface) of the platen 5 is processed to be as flat and smooth as possible, with high precision. In addition, to prevent the roll paper 30 from lifting off the guide surface 5a of the platen 5, the suction device 8 is used to suction the roll paper 30 to the guide surface 5a of the platen 5, thereby suppressing fluctuations in the gap between the roll paper 30 and the liquid discharge head 12.

[0018] Thus, if a configuration is adopted to suppress the gap fluctuation, such as making the guide surface 5a of the platen 5 a highly precise flat surface or adhering the roll paper 30 to the platen 5, the frictional area and frictional force between the platen 5 and the roll paper 30 during roll paper transport will increase, making the roll paper 30 and the platen 5 more prone to triboelectric charging.

[0019] When the roll paper 30 and the platen 5 are triboelectrically charged, the roll paper 30 adheres to the guide surface 5a of the platen 5 due to electrostatic force. As a result, the conveyance load at the position where the roll paper 30 adheres increases, which hinders appropriate conveyance of the roll paper 30. In particular, when the conveyance load at the position where the roll paper 30 adheres increases, as shown in FIG. 3, the roll paper portion B on the upstream side in the roll paper conveyance direction of the position A where the roll paper 30 adheres may lift off from the guide surface 5a of the platen 5. In this case, there is a risk that the lifted roll paper portion B may catch on the carriage 11 and cause a jam, or the lifted roll paper portion B may contact the liquid ejection head 12 and cause damage to the liquid ejection head 12 or the like.

[0020] Therefore, in the present embodiment, a protruding portion that protrudes from the guide surface 5a of the platen 5 is provided, and the protruding portion is configured to protrude from the guide surface 5a of the platen 5 during conveyance of the roll paper 30. According to this configuration, during conveyance of the roll paper 30, the portion of the roll paper that passes over the protruding portion protruding from the guide surface 5a of the platen 5 lifts off from the guide surface 5a of the platen 5 and separates from the guide surface 5a of the platen 5. As a result, triboelectric charging between the roll paper 30 and the platen 5, which occurs due to conveyance of the roll paper 30, is suppressed, and adhesion between the roll paper 30 and the platen 5 can be inhibited. Therefore, various problems such as the occurrence of jams and damage to the liquid ejection head 12 caused by the adhesion can be suppressed.

[0021] FIG. 4 is an exploded perspective view showing the platen 5 and the protruding portion moving mechanism 50 including the protruding portion 53 in the present embodiment. The protruding portion moving mechanism 50 comprises a motor 51 as a drive source, a rotating shaft member 52 extending in a direction perpendicular to the roll paper transport direction (roll paper width direction), and a protruding portion 53 provided on the rotating shaft member 52. In this embodiment, multiple protruding portions 53 are provided at multiple locations on the rotating shaft member 52 that are in different axial directions, and each protruding portion 53 is arranged on the rotating shaft member 52 so as to extend radially in the same direction from the rotating shaft member 52. The number and arrangement of the protruding portions 53 can be set as appropriate.

[0022] The platen 5 is provided with a through hole 5c through which a projection 53 on the rotating shaft member 52 passes. The rotating shaft member 52 is located below the platen 5, and the projection 53 on the rotating shaft member 52 is positioned to protrude from the guide surface 5a of the platen 5 through the through hole 5c of the platen 5.

[0023] The motor 51 is provided on one axial end of the rotating shaft member 52 and rotates the rotating shaft member 52 axially. The motor 51 is connected to the control unit 70 and is driven and controlled by the control unit 70. By rotating the rotating shaft member 52 axially with the drive of the motor 51, it is possible to switch between a protruding state in which the protruding portion 53 protrudes from the guide surface 5a of the platen 5 and a retracted state in which the protruding portion 53 retracts from the guide surface 5a of the platen 5 (i.e., a non-protruding state in which the protruding portion 53 does not protrude from the guide surface 5a of the platen 5).

[0024] Figure 5 is a flowchart showing the flow of the printing operation in this embodiment. When a print command is received and printing begins (S1), the control unit 70 controls the motor 51 of the protruding part moving mechanism 50 to rotate the rotating shaft member 52 so that the protruding part 53 on the rotating shaft member 52 protrudes from the guide surface 5a of the platen 5 (S2). The control unit 70 also controls the suction device 8 to stop its suction operation (S3). Then, the control unit 70 controls the transport roller 4a to transport a predetermined amount of the roll paper 30 (S4).

[0025] As described above, in this embodiment, the protruding portion 53 protrudes during roll paper transport, so as shown in Figure 6, during the transport of the roll paper 30, the portion of the roll paper C passing over the protruding portion 53 lifts up from the guide surface 5a of the platen 5 and separates from the guide surface 5a of the platen 5. Therefore, the contact area between the roll paper 30 and the platen 5 during roll paper transport (rubbing) is reduced. In addition, in this embodiment, the suction operation of the suction device 8 is stopped during roll paper transport, so the contact pressure between the roll paper 30 and the platen 5 is also small. As a result, the triboelectric charging between the roll paper 30 and the platen 5 that was generated by the transport of the roll paper 30 is suppressed, and sticking between the roll paper 30 and the platen 5 is suppressed. Therefore, various problems such as jams caused by this sticking and damage to the liquid discharge head 12 can be suppressed.

[0026] The amount of protrusion of the protruding portion 53 from the guide surface 5a in the protruding state is preferably 0.5 mm or more and 2 mm or less. If the protrusion amount is less than 0.5 mm, the roll paper 30 being transported cannot be sufficiently lifted, the effect of suppressing triboelectric charging is insufficient, and there is a risk that sticking between the roll paper 30 and the platen 5 cannot be sufficiently suppressed. Also, if the protrusion amount exceeds 2 mm, there is a risk that the roll paper 30 being transported, which is lifted by the protruding portion 53, will come into contact with the liquid discharge head 12. However, if the carriage 11 is waiting in a position away from above the roll paper 30 during roll paper transport, the protrusion amount may exceed 2 mm, but considering the transportability of the roll paper, it is preferable that the protrusion amount be 2 mm or less.

[0027] After transporting a certain amount of roll paper 30 and stopping, the control unit 70 controls the motor 51 of the protrusion movement mechanism 50 to rotate the rotating shaft member 52, so that the protrusion 53 on the rotating shaft member 52 is retracted away from the guide surface 5a of the platen 5 (S5). The control unit 70 also controls the suction device 8 to start the suction operation of the suction device 8 (S6). Then, the control unit 70 controls the liquid ejection unit 10 according to the image information (printing information), and performs a liquid ejection operation in which ink (liquid) is ejected from the liquid ejection head 12 while moving the carriage 11 in the roll paper width direction (S7), thereby forming an image on the roll paper 30.

[0028] In this embodiment, the protrusion 53 is retracted during the liquid discharge operation, so as shown in Figure 7, the portion of the roll paper passing above the protrusion 53 during the liquid discharge operation does not lift off the guide surface 5a of the platen 5. In particular, in this embodiment, the suction operation of the suction device 8 is performed during the liquid discharge operation, so the suction force of the suction device 8 causes the roll paper 30 to adhere tightly to the guide surface 5a of the platen 5. As a result, the roll paper 30 is held in a properly flat state along the guide surface 5a during the liquid discharge operation without being obstructed by the protrusion 53. Therefore, the liquid discharge operation is performed with suppressed gap fluctuations between the roll paper 30 and the liquid discharge head 12, making it possible to form a high-quality image.

[0029] In particular, in this embodiment, the protrusion 53 is configured to protrude from the guide surface 5a of the platen 5 at a position away from the liquid discharge area where the liquid discharge unit 10 performs liquid discharge in the roll paper transport direction (in this embodiment, a position downstream of the liquid discharge unit 10 in the roll paper transport direction). As a result, there is no through hole 5c for the protrusion 53 on the guide surface 5a of the platen 5 facing the liquid discharge area, making it easier to maintain the flat state of the roll paper 30 held on the guide surface 5a and to form a high-quality image.

[0030] In this embodiment, the protruding portion 53 is kept in the protruding state for the entire duration of the conveyance of the roll paper 30 (while the roll paper 30 is being conveyed). However, control may be performed to keep the protruding portion 53 in the protruding state only for a portion of the conveyance of the roll paper 30. For example, the protruding portion 53 may be in the retracted state immediately after the start of roll paper conveyance, and then in the protruding state for the rest of the roll paper conveyance period. Alternatively, for example, the protruding portion 53 may be kept in the protruding state until just before the roll paper conveyance stops, and then retracted just before the roll paper conveyance stops. Even with such control, where the protruding portion 53 is kept in the protruding state only for a portion of the conveyance of the roll paper 30, frictional charging between the roll paper 30 and the platen 5 during the conveyance of the roll paper 30 can be suppressed, and sticking between the roll paper 30 and the platen 5 can be suppressed.

[0031] In this embodiment, the "liquid discharge head" is a functional component that discharges or sprays liquid from a nozzle. The discharged liquid can be any liquid that has the viscosity and surface tension to be discharged from the head. Specifically, this includes solutions, suspensions, emulsions, etc., containing solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functional materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, calcium, and edible materials such as natural pigments. These can be used, for example, in inkjet inks, surface treatment liquids, liquids for forming components of electronic elements and light-emitting elements or electronic circuit resist patterns, and 3D molding material liquids.

[0032] A "liquid discharge unit" is a collection of components related to liquid discharge, in which functional parts and mechanisms are integrated with the liquid discharge head 12. For example, a "liquid discharge unit" may include a combination of the liquid discharge head 12 with at least one of the following components: a supply circulation mechanism, a carriage 11, a maintenance and recovery mechanism, and a main scanning and moving mechanism. Here, integration includes, for example, cases where the liquid discharge head 12 and the functional parts and mechanisms are fixed to each other by fastening, bonding, engaging, etc., or where one is held movably relative to the other. The liquid discharge head 12 and the functional parts and mechanisms may also be configured to be detachable from each other.

[0033] For example, some liquid dispensing units 10 have a liquid dispensing head 12 and a supply circulation mechanism integrated into one unit. Others have a liquid dispensing head 12 and a supply circulation mechanism integrated by being connected to each other by a tube or the like. Here, a unit including a filter can also be added between the supply circulation mechanism and the liquid dispensing head 12 of these liquid dispensing units 10. Others have a liquid dispensing unit 10 in which the liquid dispensing head 12 and a carriage 11 are integrated into one unit. Others have a liquid dispensing unit 10 in which the liquid dispensing head 12 is movably held by a guide member that constitutes part of a scanning movement mechanism, thereby integrating the liquid dispensing head 12 and the scanning movement mechanism. Others have a liquid dispensing unit 10 in which a cap member, which is part of a maintenance and recovery mechanism, is fixed to the carriage 11 to which the liquid dispensing head 12 is attached, thereby integrating the liquid dispensing head 12, carriage 11, and maintenance and recovery mechanism. Others have a liquid dispensing unit 10 in which a tube is connected to the liquid dispensing head 12 to which a supply circulation mechanism or flow path component is attached, thereby integrating the liquid dispensing head 12 and the supply mechanism. Through this tube, the liquid from the liquid storage source is supplied to the liquid discharge head 12. The main scanning movement mechanism also includes a guide member. The supply circulation mechanism also includes a tube and a loading unit. The supply circulation mechanism also includes a sub-tank mounted on the carriage that temporarily stores the liquid from the liquid storage source and supplies it to the liquid discharge head 12.

[0034] The "liquid dispensing device" is a device that includes a liquid dispensing head 12 or a liquid dispensing unit 10 and drives the liquid dispensing head 12 to dispense liquid. This "liquid dispensing device" may also include a conveying device 20 for feeding, transporting, and dispensing paper onto which liquid can adhere, as well as other pre-processing devices, post-processing devices, etc.

[0035] For example, "devices that eject liquid" include image forming devices such as inkjet recording devices, which eject ink to form images on paper. Furthermore, "devices that eject liquid" are not limited to those in which meaningful images such as letters or figures are visualized by the ejected liquid. For example, devices that form patterns that do not have meaning in themselves are also included.

[0036] The term "materials to which liquid can adhere" above refers to materials to which liquid can adhere, at least temporarily, including materials that adhere and solidify, or materials that adhere and penetrate. Specific examples include recording media such as paper, recording paper, film, and cloth; electronic components such as electronic circuit boards and piezoelectric elements; powder layers; organ models; and testing cells. Unless otherwise specified, it includes all materials to which liquid can adhere. The materials of the above-mentioned "materials to which liquid can adhere" can be paper, thread, fibers, fabrics, leather, metals, plastics, glass, wood, ceramics, etc., as long as liquid can adhere to them, even temporarily.

[0037] Furthermore, the term "liquid dispensing device" includes, but is not limited to, a device in which the liquid dispensing head 12 and the object to which the liquid can adhere move relative to each other. Specific examples include serial type devices in which the liquid dispensing head 12 moves, and line type devices in which the liquid dispensing head 12 does not move. In addition, other examples of "liquid dispensing devices" include processing liquid coating devices that dispense processing liquid onto the surface of paper for purposes such as modifying the surface of the paper. Moreover, in the terminology used in this application, image formation, recording, printing, copying, printing, and molding are all considered synonymous.

[0038] The above is just one example; each of the following embodiments produces its own unique effects. [First aspect] The first embodiment is a liquid dispensing device (e.g., inkjet recording device 100) comprising a transport unit (e.g., transport device 20) that transports a medium to be dispensed (e.g., roll paper 30) while in contact with a medium holding surface (e.g., guide surface 5a of platen 5), and a liquid dispensing unit (e.g., liquid dispensing unit 10) that dispenses liquid onto the medium to be dispensed held at a predetermined location on the medium holding surface, wherein the liquid dispensing operation is performed when the transport of the medium to be dispensed is stopped, and is characterized by having a protruding portion 53 that protrudes from the medium holding surface, a switching unit (e.g., protruding portion moving mechanism 50) that switches between a protruding state in which the protruding portion protrudes from the medium holding surface and a retracted state in which it is retracted from the medium holding surface, and a control unit 70 that controls the switching unit so that it takes the protruding state during the transport of the medium to be dispensed and the retracted state during the liquid dispensing operation. To achieve high-precision liquid dispensing, it is important to maintain a predetermined distance (gap) between the liquid dispensing head and the medium to be dispensed. In this embodiment, liquid is dispensed onto the medium to be dispensed, which is held at a predetermined location on the medium holding surface. When the medium to be dispensed is transported while in contact with this medium holding surface, frictional charging occurs between the medium holding surface and the medium to be dispensed, and the medium holding surface and the medium to be dispensed may stick together due to electrostatic force. When such sticking occurs, the transport load at the point of sticking increases, hindering the proper transport of the medium to be dispensed. In particular, if the transport load increases at the point of sticking, the portion of the medium to be dispensed upstream of the point of sticking in the transport direction may lift away from the medium holding surface, which may cause jamming in the lifted portion of the medium to be dispensed, or the lifted portion of the medium to be dispensed may come into contact with the liquid dispensing part, potentially causing damage to the liquid dispensing part. In this embodiment, a protruding portion is provided that extends from the media holding surface, and during the transport of the medium to be discharged, the protruding portion is controlled to remain in a protruding state from the media holding surface. This allows the portion of the medium to be discharged that passes over the protruding portion and its surroundings to be separated from the media holding surface during the transport of the medium to be discharged. Therefore, the triboelectric charge that occurs between the medium to be discharged and the media holding surface during the transport of the medium to be discharged can be reduced or suppressed, thereby preventing the medium holding surface and the medium to be discharged from sticking together, and thus suppressing various problems caused by this sticking. Furthermore, in this embodiment, the protruding part is controlled to retract from the media holding surface during liquid discharge. As a result, the media to be discharged is properly held on the media holding surface without being obstructed by the protruding part during liquid discharge, so that the distance (gap) between the liquid discharge head and the media to be discharged can be maintained at a predetermined distance, and the protruding part does not hinder the realization of high-precision liquid discharge. Furthermore, according to this embodiment, since sticking itself can be suppressed, the time required for processing when sticking occurs can be reduced, and downtime is suppressed.

[0039] [Second aspect] The second embodiment is characterized in that, in the first embodiment, the transport unit includes transport members (for example, a transport roller 4a and a pressure roller 4b) that apply a transport force to the medium to be discharged on the upstream side in the transport direction of the liquid discharge unit. In such a configuration, when the media holding surface and the media to be discharged stick together due to triboelectric charging, the portion of the media to be discharged that lifts up from the media holding surface due to the conveying force applied by the conveying member upstream in the conveying direction is prone to getting caught in the liquid discharge section and causing a jam. Alternatively, the portion of the media to be discharged that lifts up from the media holding surface is prone to coming into contact with the liquid discharge head of the liquid discharge section, potentially causing damage to the liquid discharge head. In this embodiment, even with such a configuration, sticking between the media to be discharged and the media holding surface can be suppressed.

[0040] [Third aspect] The third embodiment is characterized in that, in the first or second embodiment, the liquid dispensing operation is not performed while the dispensing medium is being transported. According to this, compared to a configuration in which the liquid discharge operation is performed while the medium to be discharged is being transported, the liquid discharge operation can be performed with less fluctuation in the distance (gap) between the medium to be discharged and the liquid discharge unit, thus enabling more precise liquid discharge.

[0041] [Fourth aspect] The fourth embodiment is a liquid discharge method characterized in that, in any of the first to third embodiments, the control unit controls the switching unit so that it takes the protruding state for part or all of the period during the transport of the discharge medium. By keeping the protruding portion in an extended state for at least a portion of the time during the transport of the medium to be discharged, frictional charging between the medium to be discharged and the medium holding surface during transport can be suppressed, thereby preventing sticking between the medium holding surface and the medium to be discharged, and thus suppressing various problems caused by this sticking.

[0042] [Fifth aspect] The fifth embodiment is characterized in that, in any of the first to fourth embodiments, the control unit controls the switching unit so that it maintains the retracted state throughout the liquid discharge operation. According to this, the dispensing medium can be held against the medium-holding surface without being obstructed by the protruding part throughout the liquid dispensing operation, thus enabling continuous high-precision liquid dispensing.

[0043] [Sixth aspect] The sixth embodiment is characterized in that, in any of the first to fifth embodiments, the protruding portion is provided to protrude from the rotating shaft member 52 in a direction perpendicular to the axial direction of the rotating shaft member, and the switching portion switches between the protruding state and the retracted state by changing the rotational position of the rotating shaft member. According to this, it is possible to switch between the extended state and the retracted state with a simple configuration.

[0044] [Seventh aspect] The seventh embodiment is characterized in that, in any of the first to sixth embodiments, the amount of the protruding portion in the protruding state protruding from the media holding surface is 0.5 mm or more and 2 mm or less. According to this, it is easier to achieve proper transport without hindering the transportability of the dispensed medium, while sufficiently suppressing adhesion between the dispensed medium and the medium holding surface.

[0045] [8th aspect] The eighth aspect is characterized in that, in any of the first to seventh aspects, the liquid discharge unit includes a liquid discharge head 12 that moves in a direction perpendicular to the direction in which the medium to be discharged is conveyed by the conveying unit. According to this, in a so-called serial-type device, adhesion between the discharged medium and the medium holding surface can be suppressed, thereby enabling stable and proper transport of the discharged medium.

[0046] [Ninth aspect] The ninth embodiment is characterized in that, in any of the first to eighth embodiments, the protruding portion protrudes from the medium holding surface downstream of the liquid discharge portion in the transport direction of the medium to be discharged. If adhesion occurs between the medium to be dispensed and the medium holding surface downstream of the liquid dispensing section in the transport direction, the portion of the medium to be dispensed upstream of the adhesion point in the transport direction may lift away from the medium holding surface. In this case, the lifted portion of the medium to be dispensed may come into contact with the liquid dispensing section, potentially causing jams or damage to the liquid dispensing section. In this embodiment, the protruding portion can be made to protrude from the media holding surface at the location where sticking, which causes such problems, occurs. Therefore, the sticking that causes such problems can be suppressed, and the aforementioned problems can be suppressed.

[0047] [Tenth aspect] The tenth embodiment is characterized in that, in any of the first to ninth embodiments, the present invention has a suction unit (e.g., a suction device 8) that sucks up the medium to be discharged and adsorbs it onto the medium holding surface, wherein the suction unit performs suction during the liquid discharge operation but does not perform suction during the transport of the medium to be discharged. According to this design, during liquid dispensing, suction is performed by the suction unit to properly hold the dispensing medium along the medium holding surface, allowing for liquid dispensing to be performed on that medium, thus achieving high-precision liquid dispensing. On the other hand, since suction is not performed by the suction unit during the transport of the dispensing medium, the contact pressure between the dispensing medium and the medium holding surface during transport is reduced, suppressing triboelectric charging and preventing various problems caused by sticking between the dispensing medium and the medium holding surface. [Explanation of symbols]

[0048] 2: Paper feeder 3: Paper feed guide plate 4a: Conveyor roller 4b: Pressure roller 5: Platen 5a: Guide surface 5b: Suction hole 5c: Through hole 6: Paper output guide plate 7: Winding device 8:Suction device 10: Liquid dispensing unit 11: Carriage 12: Liquid dispensing head 20: Conveying device 30: Roll paper 40: Platen Unit 50: Protrusion moving mechanism 51: Motor 52: Rotating shaft member 53:Protrusion 70: Control Unit 100: Inkjet recording device [Prior art documents] [Patent Documents]

[0049] [License 1] Patent No. 4426864

Claims

1. A conveying unit that transports the medium to be dispensed while in contact with the medium holding surface, The system comprises a liquid dispensing unit that dispenses liquid onto a medium to be dispensed, which is held at a predetermined location on the medium holding surface, A liquid dispensing device that performs the liquid dispensing operation while the transport of the medium to be dispensed is stopped, A protruding portion that protrudes from the media holding surface, A switching unit that switches between a protruding state in which the protruding portion protrudes from the media holding surface and a retracted state in which the protruding portion retracts from the media holding surface, A liquid dispensing device characterized by having a control unit that controls the switching unit to take the protruding state during the transport of the medium to be dispensed and the retracted state during the liquid dispensing operation.

2. In the apparatus for dispensing liquid according to claim 1, The device for discharging liquid is characterized in that the conveying section includes a conveying member that applies a conveying force to the medium to be discharged on the upstream side in the conveying direction of the liquid discharge section.

3. In a liquid dispensing apparatus according to claim 1 or 2, A liquid dispensing device characterized in that the liquid dispensing operation is not performed while the medium to be dispensed is being transported.

4. In a liquid dispensing apparatus according to claim 1 or 2, The liquid dispensing device is characterized in that the control unit controls the switching unit so that it takes the protruding state for part or all of the period during the transport of the medium to be dispensed.

5. In a liquid dispensing apparatus according to claim 1 or 2, A liquid dispensing device characterized in that the control unit controls the switching unit so that it maintains the retracted state throughout the liquid dispensing operation.

6. In a liquid dispensing apparatus according to claim 1 or 2, The aforementioned protrusion is provided so as to protrude from the rotating shaft member in a direction perpendicular to the axial direction of the rotating shaft member. The switching unit is characterized by switching between the protruding state and the retracted state by changing the rotational position of the rotating shaft member, thereby enabling the discharge of liquid.

7. In a liquid dispensing apparatus according to claim 1 or 2, A liquid dispensing device characterized in that the amount of the protruding portion protruding from the medium holding surface in the protruding state is 0.5 mm or more and 2 mm or less.

8. In a liquid dispensing apparatus according to claim 1 or 2, The liquid dispensing device is characterized in that the liquid dispensing unit includes a liquid dispensing head that moves in a direction perpendicular to the direction in which the medium to be dispensed is conveyed by the conveying unit.

9. In a liquid dispensing apparatus according to claim 1 or 2, A liquid dispensing device characterized in that the protruding portion protrudes from the medium holding surface downstream of the liquid dispensing portion in the transport direction of the medium to be dispensed.

10. In a liquid dispensing apparatus according to claim 1 or 2, It has a suction unit that sucks up the discharged medium and causes it to adhere to the medium holding surface, The suction unit is characterized in that it performs suction during the liquid discharge operation but does not perform suction while the medium to be discharged is being transported.

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