conveying device

Abstract

The present invention provides a conveyance device capable of stably attracting and conveying a print medium and preventing deterioration of image quality caused by mist. The conveyance device includes a conveyance belt (11) that attracts and conveys a print medium, and a sheet member (30) that is placed on the print medium (P) conveyed by the conveyance belt (11) and has flexibility, the sheet member (30) covering a range on the conveyance belt (11) corresponding to a periphery of an ejection portion that ejects a droplet toward the print medium (P).

Description

Technical Field

[0001] This invention relates to a handling device for transporting printed media. Background Technology

[0002] In the past, inkjet printing devices were proposed that carried out printing by simultaneously transporting printing media made of paper or film and ejecting ink from an inkjet head onto the printing media.

[0003] As a medium transport device in such an inkjet printing apparatus, a transport device using a transport belt has been proposed. Specifically, a transport device is proposed in which an suction fan is provided on the back side of the transport surface of the printing medium on the transport belt, and the rotation of the suction fan generates a negative pressure in a plurality of suction holes formed in the transport belt, thereby causing the printing medium to be adsorbed onto the transport belt (see, for example, Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-280321 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Here, in the suction transport method described above, the force (adsorption force) for adsorbing the printing medium is determined by the output of the suction fan used to generate negative pressure. In order to stably transport the printing medium without it detaching from the transport surface, a high adsorption force is required, therefore it is desirable for the output of the suction fan to be as high as possible.

[0009] However, when the output of the suction fan is increased, a suction-induced wind (suction wind) is generated on the upper surface of the conveyor belt, and the higher the fan output, the greater the speed of the suction wind. During suction transport, the mist (tiny ink droplets other than the main droplets) generated when the ink is ejected flows out through the aforementioned suction wind, causing droplets to fall at positions far from the main droplets, resulting in the observed image blurring and image degradation. Figure 11 It is a diagram to illustrate the fog that flows out due to the attraction of wind.

[0010] In addition, if the speed of the suction wind increases, the distance from which the fog flows out increases, and the fog droplets fall at a position farther away from the main droplet, thus causing further degradation in image quality.

[0011] In view of the above, the object of the present invention is to provide a conveying device that can stably attract and convey printing media and prevent image quality degradation caused by fog.

[0012] Methods for solving problems

[0013] The conveying device of the present invention comprises: a conveying section that adsorbs and conveys a printing medium; and a sheet member that is placed on the printing medium conveyed by the conveying section and is flexible, the sheet member covering a region on the conveying section corresponding to the area around the ejection section that ejects droplets onto the printing medium.

[0014] Invention Effects

[0015] According to the present invention, the conveying device is able to stably attract and convey the printing medium and prevent image quality degradation caused by fog because it is provided with a sheet member that is flexible and covers the area of ​​the conveying part corresponding to the area around the ejection part, and is placed on the printing medium to be attracted and conveyed. Attached Figure Description

[0016] Figure 1 This is a diagram illustrating the schematic configuration of an inkjet printing apparatus using one embodiment of the conveying device of the present invention.

[0017] Figure 2 This is a diagram showing the transport unit and sheet components as viewed from above.

[0018] Figure 3 This is a diagram showing the configuration of six inkjet heads contained in a line head.

[0019] Figure 4 It is a diagram showing how ink ejected from the inkjet head drips onto the printing medium through holes formed in the sheet material.

[0020] Figure 5 It means Figure 2 The diagram shows a sectional view of the retaining mechanism along line AA.

[0021] Figure 6 This is a block diagram showing the general structure of the control system of an inkjet printing device.

[0022] Figure 7 This is a diagram illustrating other implementations of the retaining mechanism.

[0023] Figure 8 It means Figure 7 The figure shows a BB-line sectional view of the opening of the retaining mechanism.

[0024] Figure 9 This is a diagram illustrating other implementations of the retaining mechanism.

[0025] Figure 10 yes Figure 9 The shown is a CC-line sectional view of the retaining mechanism.

[0026] Figure 11This diagram is intended to illustrate the problems with existing inkjet printing devices.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1: Inkjet printing equipment;

[0029] 10: Transport unit;

[0030] 11: Conveying belt;

[0031] 11a: Suction hole;

[0032] 12: Impression roller;

[0033] 13: Attracts the fan;

[0034] 14: Transport roller;

[0035] 20: Image forming unit;

[0036] 21: Line heading;

[0037] 21a: Inkjet head;

[0038] 22: Nozzle holder;

[0039] 30: Sheet components;

[0040] 30a: Hole;

[0041] 31: Maintain the organization;

[0042] 32: Metal components;

[0043] 35a: Inclined portion;

[0044] 35b: Flat part;

[0045] 41: Maintain the organization;

[0046] 43, 44: Openings;

[0047] 50: Control Department;

[0048] 60: Maintain the organization;

[0049] CL: Inclined surface;

[0050] P: Printing medium;

[0051] S: narrow slit. Detailed Implementation

[0052] Hereinafter, an inkjet printing apparatus using one embodiment of the conveying device of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a schematic diagram of the inkjet printing apparatus 1 according to this embodiment. It should be noted that... Figure 1 The up, down, left, and right directions indicated by arrows are defined as the up, down, left, and right directions in the inkjet printing apparatus 1 of this embodiment. Furthermore, relative to... Figure 1 The front side of the paper is designated as the forward direction, and the inner side as the rear direction. Furthermore, in this embodiment, the direction from left to right is the transport direction of the printing medium P.

[0053] like Figure 1 As shown, the inkjet printing apparatus 1 of this embodiment includes a transport unit 10 and an image forming unit 20.

[0054] The transport unit 10 includes a transport belt 11, an impression roller 12, a suction fan 13, and a transport roller 14. In this embodiment, the transport unit 10 corresponds to the transport section of the present invention.

[0055] The conveyor belt 11 and the impression roller 12 are directly supported by the housing of the inkjet printing apparatus 1 or indirectly suspended by components other than the housing.

[0056] The transport belt 11 is an annular belt and has multiple suction holes 11a formed thereon for adsorbing the printing medium P. Figure 2 (The white circle shown). The impression roller 12 is a roller that extends in a direction orthogonal to the transport direction of the printing medium P (front-to-back direction). For example... Figure 1 As shown, in this embodiment, four impression rollers 12 are provided.

[0057] A transport belt 11 is mounted on the four impression rollers 12. One of the four impression rollers is a drive roller, and the other three are driven rollers. By rotating the impression roller 12, which acts as the drive roller, the transport belt 11 moves, thereby causing the driven rollers 12 to rotate together with the transport belt 11. As a result, the printing medium P adsorbed on the transport belt 11 is transported. In this embodiment, the impression rollers 12 move towards... Figure 1 The printing medium P, which is adsorbed onto the transport belt 11, rotates clockwise. Figure 1 The contents are moved from left to right. Figure 1 The left side is the upstream side of the transport direction, and the right side is the downstream side of the transport direction.

[0058] On the back side of the transport surface of the printing medium P in the transport belt 11, two suction fans 13 are provided on the upstream and downstream sides. By rotating the suction fans 13, a negative pressure is generated in the suction hole 11a of the transport belt 11, thereby attracting the printing medium P to the transport belt 11.

[0059] Seven transport rollers 14 are disposed above the transport belt 11. The transport rollers 14 are located near the top of the transport belt 11 and extend in a direction orthogonal to the transport direction of the printing medium P. The transport rollers 14 are arranged at predetermined intervals in the transport direction. Specifically, they are respectively disposed on both sides of the transport direction of each of the line heads 21 described later. Each transport roller 14 extends towards... Figure 1 The roller rotates counterclockwise and pushes the printing medium P, which is being transported directly below it, from above while feeding the printing medium P downstream.

[0060] In order to stably transport the printing medium P without it detaching from the transport surface, as described above, and to achieve a high adsorption force, it is desirable that the output of the suction fan 13 be as high as possible. However, when the output of the suction fan 13 is increased, a suction-induced wind (suction wind) is generated on the upper surface of the transport belt 11, and ink mist (tiny ink droplets other than the main droplets) flows out with the suction wind, resulting in image quality degradation.

[0061] Therefore, in this embodiment, the inkjet printing apparatus 1 has a sheet member 30 provided between the line head 21 and the conveying surface of the conveyor belt 11. Figure 2 It is viewed from above. Figure 1 The diagram shows the conveying unit 10 and the sheet component 30.

[0062] In this embodiment, the sheet member 30 is a sheet-like member that covers the area on the transport belt 11 corresponding to the area around each inkjet head 21a constituting the printhead 21. Specifically, the sheet member 30 has the same width as the transport belt 11 in a direction orthogonal to the transport direction of the printing medium P (front-back direction), and is a rectangular sheet-like member extending to the downstream end of the transport belt 11 in the transport direction. Furthermore, in the sheet member 30, a hole 30a is formed in the area corresponding to the ink ejection range of each inkjet head 21a, through which ink ejected from each inkjet head 21a drips onto the printing medium P.

[0063] In this embodiment, each printhead 21 has six inkjet heads 21a. Figure 3 This diagram illustrates the configuration of six inkjet heads 21a within a single line printhead 21. (See diagram for example.) Figure 3 As shown, the line print head 21 of this embodiment is composed of six inkjet heads 21a arranged in an alternating pattern.

[0064] Therefore, the holes 30a formed in the sheet member 30 are also formed in the ink ejection range of each inkjet head 21a that is staggered in each row head 21.

[0065] Figure 4This diagram illustrates how ink ejected from the inkjet head 21a drips onto the printing medium P through holes 30a formed in the sheet member 30. (See diagram for example.) Figure 4 As shown, the sheet member 30, in the portion outside the range of the printing medium P, is adsorbed onto the suction hole 11a of the transport belt 11. Thus, the sheet member 30 is constantly adsorbed onto the transport belt 11, and the printing medium P being transported between the transport belt 11 and the sheet member 30 is pressed down by the sheet member 30, thereby preventing the printing medium P from detaching from the transport belt 11. This prevents the printing medium P from contacting the inkjet head 21a due to warping or other reasons.

[0066] Furthermore, the hole 30a in the sheet member 30 is located directly below the nozzle of the inkjet head 21a, and the sheet member 30 covers the transport belt 11 around the ink ejection range of the inkjet head 21a, thus preventing the formation of suction wind under the inkjet head 21a that would cause the ink mist to flow away from the main droplet. This prevents image degradation caused by ink mist during suction transport.

[0067] Furthermore, by providing the sheet member 30 on the conveyor belt 11, most of the suction holes 11a on the conveyor belt 11 are blocked, thus reducing the loss of the generated negative pressure. As a result, compared to the configuration without the sheet member 30, the output of the suction fan 13 can be reduced, thereby reducing power consumption.

[0068] It should be noted that the width of the hole 30a in the transport direction of the sheet component 30 is a tiny width of the nozzle array of the inkjet head 21a. Therefore, the presence of the hole 30a will not cause the printing medium P to detach from the transport surface.

[0069] The sheet component 30 is formed, for example, from PET (polyethylene terephthalate) with a thickness of approximately 0.2 mm. The material of the sheet component 30 is not limited to PET; any material that allows the sheet component 30 to flex under its own weight can be used, such as other resins. Furthermore, a film with an uneven surface, such as a microbead film, is preferably used as the sheet component 30. In particular, it is preferable to form the aforementioned unevenness on the surface of the sheet component 30 that contacts the printing medium P.

[0070] By using such a sheet component 30, it is possible to prevent ink from being absorbed into the sheet component 30 due to contact between the printing surface of the printing medium P and the surface of the sheet component 30, and then being transferred to the printing medium P, thus preventing contamination of the printing medium P.

[0071] Alternatively, the surface of the sheet member 30 on the side of the printing head 21 can be made of a material similar to an absorbent material. As an absorbent material, a felt-like sheet (cloth-like), a sponge-like component, or a cotton-like component that allows ink to permeate through capillary force can be used. Therefore, the sheet member 30 can absorb ink mist, extending the ink replacement cycle.

[0072] Furthermore, the upstream end of the sheet member 30 is held by a holding mechanism 31. The holding mechanism 31 is an elongated rectangular plate-shaped member extending in a direction orthogonal to the transport direction (front-back direction). The holding mechanism 31 is threadedly fixed relative to the metal members 32 provided on both sides in a direction orthogonal to the transport direction of the transport belt 11.

[0073] Figure 5 It means Figure 2 A cross-sectional view along line AA around the retaining mechanism 31 is shown. Figure 5 As shown, the holding mechanism 31 of this embodiment has a cross-section shaped like the Chinese character "く" and includes an inclined portion 35a and a flat portion 35b. The inclined portion 35a of the holding mechanism 31 is formed to rise vertically towards the upstream side of the transport direction of the printing medium P, and the lowest part of the inclined portion 35a is connected to the flat portion 35b. The inclination angle of the transport surface relative to the inclined portion 35a is approximately 20 degrees.

[0074] By forming the inclined portion 35a in this way, the vertical distance between the insertion port of the printing medium P formed between the holding mechanism 31 and the transport surface of the transport belt 11 can be increased. As a result, collisions between the printing medium P and the holding mechanism 31 can be suppressed.

[0075] Moreover, such as Figure 5 As shown, the upstream end of the sheet member 30 is mounted to the upper surface of the flat portion 35b, for example, by means of double-sided tape, glue, etc.

[0076] The retaining mechanism 31 is positioned above the transport surface of the transport belt 11 at a predetermined distance. As described above, the upper end of the sheet member 30 is bonded to the upper surface of the flat portion 35b of the retaining mechanism 31, thereby configuring the portion extending downstream from the upper end of the sheet member 30 to be flexed and inclined. By inclining the sheet member 30 in this way, the sheet member 30 applies force to the transport surface of the transport belt 11, thereby pressing the printing medium P onto the transport surface.

[0077] The tilt angle θ of the inclined surface CL of the sheet member 30 relative to the transport surface is approximately 30 degrees, preferably 20 degrees or more and 40 degrees or less. By setting the tilt angle θ to 20 degrees or more, the pressing force of the sheet member 30 can be increased. Furthermore, by setting the tilt angle θ to 40 degrees or less, the collision of the leading edge of the printing medium P with the inclined surface CL of the sheet member 30 can be suppressed, and the leading edge of the printing medium P can be smoothly transported between the sheet member 30 and the transport surface.

[0078] Furthermore, the printing medium P, inserted between the sheet member 30 and the transport surface, is transported to the image forming unit at a predetermined transport speed.

[0079] like Figure 1 As shown, the image forming unit 20 is positioned opposite the conveyor belt 11 of the conveying unit 10, and includes six row heads 21 and a nozzle holder 22.

[0080] Each printhead 21 has multiple printheads 21a, each printhead 21a having multiple nozzles for ejecting ink.

[0081] Each line-type head 21 is a component extending in a direction orthogonal to the transport direction of the printing medium P, and is a component that ejects ink from the printing medium P transported by the transport unit 10. For example... Figure 1 As shown, six line heads 21 are arranged at predetermined intervals along the transport path of the printing medium P. The six line heads 21 are components that spray different colors (e.g., black, cyan, magenta, yellow, gray, and special colors other than those mentioned above).

[0082] The printhead holder 22 is a component for mounting the various printheads 21. The printhead holder 22 is constructed of a box-shaped support member, and multiple mounting holes are formed on the bottom surface of the printhead holder 22. Each inkjet head 21a of the various printheads 21 is embedded in these mounting holes. The mounting holes are through holes, configured such that the ink ejection surface of each inkjet head 21a is exposed on the outer side of the bottom surface of the printhead holder 22.

[0083] Furthermore, as described above, the printing medium P is pressed by the sheet member 30 while being transported directly below the image forming unit 20. Ink is ejected from each print head 21 onto the printing medium P, and the ink ejected from each print head 21a drips onto the printing medium P through the holes 30a of the sheet member 30, thereby performing the printing process.

[0084] Figure 6This is a block diagram showing the general configuration of the control system of the inkjet printing apparatus 1 according to this embodiment. The control unit 50 includes a CPU (Central Processing Unit), a semiconductor memory, and a hard disk. The control unit 50 executes a program pre-stored in a storage medium such as a semiconductor memory or a hard disk and activates the electrical circuits, thereby controlling the operation of each part of the inkjet printing apparatus 1.

[0085] Next, other embodiments of the holding mechanism 31 in the inkjet printing apparatus 1 of this embodiment will be described. Figure 7 This is a perspective view showing the state in which the retaining mechanism 41 and the sheet member 30 of other embodiments are removed. It should be noted that... Figure 7 The diagram of the hole 30a in the sheet component 30 is omitted.

[0086] The retaining mechanism 41 is an elongated rectangular plate-shaped member extending in a direction orthogonal to the transport direction. Openings 43 and 44 are formed in the retaining mechanism 41 for mounting the sheet member 30.

[0087] Figure 8 It means Figure 7 The figure shows a sectional view along line BB of the opening 43 of the retaining mechanism 41. In the opening 43 of the retaining mechanism 41, a height difference is formed at a position slightly lower than the upper surface 41a of the retaining mechanism 41. The surface below this height difference of the retaining mechanism 41 is a sheet mounting surface 41b, on which the end of the sheet member 30 is mounted. The end of the sheet member 30 is mounted to the sheet mounting surface 41b, for example, using double-sided tape, glue, or the like.

[0088] Furthermore, a slit S is formed in the opening 43 of the holding mechanism 41, extending in a direction orthogonal to the transport direction. A portion extending from the upstream end of the sheet member 30 (the portion mounted on the sheet mounting surface 41b) passes through the slit S and is disposed on the lower side of the holding mechanism 41.

[0089] As described above, the retaining mechanism 41 passes through the slit S and holds the upstream end of the sheet member 30 with the sheet mounting surface 41b. The portion extending from the upstream end of the sheet member 30 is positioned below the retaining mechanism 41. Due to the height difference between the sheet mounting surface 41b and the lower surface 41c of the retaining mechanism 41, the portion extending from the upstream end of the sheet member 30 flexes to form an inclined surface CL. In this embodiment, the width of the slit S in the transport direction is approximately 6 mm, and the height difference between the sheet mounting surface 41b and the lower surface 41c of the retaining mechanism 41 is approximately 2 mm.

[0090] The retaining mechanism 41 retains the sheet member 30 by flexing and tilting a portion extending from the upstream end of the sheet member 30, thereby applying force to the transport surface of the transport belt 11. In this way, by applying force to the transport surface of the transport belt 11 by the sheet member 30, the pressing pressure on the end of the printing medium P overlapping the sheet member 30 can be increased.

[0091] The tilt angle θ of the inclined surface CL relative to the transport surface is the same as in the above embodiment, which is about 30 degrees, preferably more than 20 degrees and less than 40 degrees.

[0092] The downstream end of the printing medium P supplied to the conveyor belt 11 is inserted between the holding mechanism 41 and the conveying surface of the conveyor belt 11. For example... Figure 7 As shown, an inclined surface 41d is formed on the lower surface of the upstream side of the holding mechanism 41. The inclined surface 41d is an inclined surface that rises from the downstream side to the upstream side. The inclination angle of the transport surface relative to the inclined surface 41d is about 20 degrees. By forming the inclined surface 41d in this way, the vertical distance between the insertion port of the printing medium P formed between the holding mechanism 41 and the transport surface of the transport belt 11 can be increased. As a result, collisions of the printing medium P with the holding mechanism 41 can be suppressed.

[0093] Furthermore, the printing medium P, inserted between the holding mechanism 41 and the transport surface of the transport belt 11, is transported downstream via the transport belt 11 and inserted between the sheet member 30 and the transport surface. An inclined surface 41e, connected to the lower surface 41c, is formed at the upstream end of the lower surface 41c of the holding mechanism 41, where the sheet member 30 is disposed below. The inclined surface 41e, like the inclined surface 41d, is an inclined surface that rises from the downstream side to the upstream side. The inclination angle of the transport surface relative to the inclined surface 41e is approximately 45 degrees.

[0094] In this way, by setting the contact portion between the upper surface of the sheet member 30 and the retaining mechanism 41 as an inclined surface instead of a right angle, the pressure per unit area on the upper surface of the sheet member 30 can be reduced, thereby reducing the load on the sheet member 30 and improving the durability of the sheet member 30.

[0095] Figure 9 This is a perspective view showing the configuration of a retaining mechanism 60 that forms an inclined surface CL on a sheet member 30, using a plate member with an inclined surface instead of a slit S like the retaining mechanism 41 described above. It should be noted that... Figure 9 The diagram of the hole 30a in the sheet component 30 is omitted.

[0096] Specifically, the holding mechanism 60 has a first plate member 51 and a second plate member 52 that are arranged to overlap with the transport surface of the transport belt 11 in the vertical direction at a predetermined interval. The second plate member 52 is arranged on the first plate member 51 at a predetermined interval.

[0097] Figure 10 yes Figure 9 The holding mechanism 60 shown is a CC-line cross-sectional view. The vertical spacing between the first plate member 51 and the second plate member 52 is set to be wider than the thickness of the sheet member 30, so that the sheet member 30 can pass between the first plate member 51 and the second plate member 52.

[0098] The first plate member 51 comprises: a horizontal portion 51b having a sheet mounting surface 51a at the upstream end of the sheet member 30; an inclined portion 51c extending upstream from the horizontal portion 51b; and an inclined portion 51d extending downstream from the horizontal portion 51b. Both the inclined portions 51c and 51d have inclined surfaces that slope downwards from the upstream side to the downstream side.

[0099] The second plate member 52 comprises: a horizontal portion 52a, which is positioned opposite to the horizontal portion 51b of the first plate member 51; and an inclined portion 52b, which extends downstream from the horizontal portion 52a. The inclined portion 52b has an inclined surface that slopes downward from the upstream side to the downstream side.

[0100] Furthermore, the sheet member 30 passes between the first plate member 51 and the second plate member 52, and its upstream end is mounted on the sheet mounting surface 51a of the first plate member 51. The upstream end of the sheet member 30 is mounted on the sheet mounting surface 51a, for example, by double-sided tape, glue, or the like.

[0101] Furthermore, by extending from the upstream end of the sheet member 30 through the inclined portion 51d of the first plate member 51 and the inclined portion 52b of the second plate member 52, the portion extending from the upstream end of the sheet member 30 flexes to form an inclined surface CL. The inclination angle θ of the transport surface relative to the inclined surface CL is preferably 20 degrees or more and 40 degrees or less.

[0102] It should be noted that the present invention is not limited to the above-described embodiments, and the constituent elements can be modified and embodied by means of changes during the implementation phase without departing from its spirit. Furthermore, various inventions can be formed by appropriate combinations of the multiple constituent elements disclosed in the above embodiments. For example, the entire constituent element shown in the embodiments can be appropriately combined. It is natural that various modifications and applications can be made in this way without departing from the spirit of the invention.

[0103] This invention relates to a conveying device, and the following notes are further disclosed.

[0104] (Note)

[0105] In the conveying device of the present invention, the sheet member can have a hole through which droplets ejected from the ejection section pass.

[0106] In the conveying device of the present invention, there is a holding portion that holds the upstream end of the sheet member in the conveying direction. The holding portion can hold the sheet member by flexing and tilting a portion extending from the upstream end of the sheet member, thereby applying force to the conveying surface of the conveying portion.

[0107] In the conveying device of the present invention, the printing medium can be passed between the sheet member and the conveying part, thereby forming an uneven surface on the surface of the sheet member that contacts the printing medium.

Claims

1. A conveying device, wherein, The conveying device includes: The transport section, which adsorbs and transports the printing medium; and A sheet component, which is placed on a printing medium transported by the transport unit and is flexible, covers the area on the transport unit corresponding to the periphery of the ejection portion that ejects droplets onto the printing medium. The printing medium passes between the sheet component and the transport unit.

2. The conveying device according to claim 1, wherein, The sheet member has holes through which droplets ejected from the ejection portion pass.

3. The conveying device according to claim 1, wherein, The conveying device has a holding part that holds the upstream end of the sheet member in the conveying direction. The retaining portion retains the sheet member by flexing and tilting a portion extending from the upstream end of the sheet member, thereby applying force from the sheet member to the transport surface of the transporting portion.

4. The conveying device according to claim 1, wherein, The surface of the sheet member that contacts the printing medium has irregularities.

5. The conveying device according to claim 1, wherein, The sheet component applies force to the transport surface of the transport section, pressing the printing medium onto the transport surface.

6. The conveying device according to claim 1, wherein, The conveying part has a suction hole, and the sheet member covers at least a portion of the suction hole.

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