Medium support shaft, medium transport device and image formation device

Abstract

To provide a medium support shaft that can reduce the work of removing a roll medium.SOLUTION: A media support shaft fixed to a roll medium formed by winding a sheet-like medium around a core member includes: a fixed part that is brought into a pressure contact state in which it is pressed against the inner wall of the core member when gas is injected and expands, and is brought into a non-pressure contact state in which it is not in contact with the inner wall when the gas is discharged and contracts; and an inner wall contact part that is provided on the outer peripheral surface of the shaft so as to contact the inner wall when in the non-pressure contact state and not to contact the inner wall when in the pressure contact state.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a medium support shaft, a medium transport device, and an image forming apparatus. [Background technology]

[0002] A medium support shaft is known that is inserted into a core of a sheet-like medium (roll medium) to fix and rotatably support the roll medium. A medium transport device is also known that rotatably holds the medium support shaft and transports the medium. Also known is an image forming apparatus that includes a medium transport device, forms an image on a medium fed from the roll medium, and rewinds the medium with the image formed on it onto the core.

[0003] As a configuration for fixing a roll medium to a medium support shaft, a technology has been disclosed in which multiple rubber members are placed on the medium support shaft, gas is injected into these rubber members to expand them against the inner wall of the core and press them against the core, thereby fixing the medium support shaft to the core (see Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 comprises a number of protruding members that are arranged to be movable and pressed against the inner diameter of the core of the roll medium, a tube adjacent to the multiple protruding members that expands when supplied with air pressure and presses the protruding members against the inner diameter of the roll paper core, an air path that supplies air to the multiple tubes, a valve that seals and blocks the air path from the outside, and a gear that receives power from a drive source and transmits rotational power to the roll paper support shaft.

[0005] In this conventional technology, when removing the roll medium from the medium support shaft, it is necessary to release the air in the expanded tube to shrink it and weaken the pressing force against the core. When the gas is released and the tube shrinks, it can get stuck inside the shaft part of the medium support shaft. If that happens, the core will rub against the shaft part of the medium support shaft when the roll medium is removed from the medium support shaft.

[0006] When the core and the media support shaft are in friction with each other, when the core is inserted or removed from the media support shaft, the edge of the through hole formed on the outer periphery of the shaft gets caught on the inner wall of the core, increasing the resistance. As a result, there is a problem that the time required to remove the roll media increases.

[0007] An object of the present invention is to provide a medium support shaft that can reduce the amount of work required to remove a roll medium. [Means for solving the problem]

[0008] In order to solve the above problems, one aspect of the present invention relates to a medium support shaft that is fixed to a roll medium consisting of a core member and a sheet-like medium wound around it, and is characterized in having a fixed portion that is in a pressed state in which it is pressed against the inner wall of the core member when gas is injected and the fixed portion expands, and is in a non-pressurized state where it is not in contact with the inner wall when the gas is discharged and the fixed portion contracts, and an inner wall contact portion provided on the outer peripheral surface of the shaft that contacts the inner wall in the non-pressurized state and does not contact the inner wall in the pressed state. Effect of the Invention

[0009] According to the present invention, the work of removing the roll medium can be reduced. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram showing an example of an embodiment of a medium conveying device and an image forming apparatus according to the present invention; [Diagram 2] FIG. 1 is a schematic diagram showing a main configuration of a conventional medium support shaft. [Diagram 3] 1A and 1B are diagrams for explaining problems with a conventional medium support shaft. [Figure 4] FIG. 2 is a schematic diagram showing a characteristic configuration of a medium support shaft according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram of an embodiment of an image forming apparatus according to the present invention. The embodiment of the image forming apparatus illustrated in Fig. 1 is a printing apparatus 500 configured to form an image on a roll medium, which is a sheet-like medium wound around a core, by an inkjet method and to wind the medium with the image formed on it around the core.

[0012] As shown in FIG. 1, the printing apparatus 500 includes a paper feed unit 501, a conveyance unit 503, a printing unit 505, a drying unit 507, and a paper discharge unit 509.

[0013] The paper feed unit 501 as a medium sending unit corresponds to an embodiment of the medium transport device according to the present invention. The paper feed unit 501 includes a holding roller 511 that holds paper 510, which is a sheet-like medium wound in a roll around a core, and supplies paper 510, which corresponds to a long continuous sheet-like medium, to the printing unit 505.

[0014] The transport unit 503 performs, for example, tension control and meandering correction on the paper 510 supplied from the paper feed unit 501 , adjusts the tension and transport position of the paper 510 , and transports the paper 510 to the printing unit 505 .

[0015] The printing unit 505 as an image forming unit includes an inkjet recording unit 550 equipped with a head unit 555, and a transport guide member 559 facing the inkjet recording unit 550. The printing unit 505 forms an image on the paper 510 by discharging ink from the head unit 555 onto the paper 510 moving on the transport guide member 559. The number of head units 555 mounted on the inkjet recording unit 550 may be appropriately increased or decreased depending on the type and number of colors of ink used in the printing device 500. The liquid used in the head unit 555 is not limited to ink, and may include a treatment liquid for modifying the surface of the paper 510, or a coating agent for protecting the image formed on the paper 510.

[0016] The drying unit 507 heats the paper 510 carrying the image, and dries the paper 510 and the image formed on the paper 510. The paper discharge unit 509 includes a winding roller 591 as a medium winding unit that winds up the paper 510, and winds up the paper 510 sent out from the drying unit 507.

[0017] It should be noted that the medium applicable to the image forming apparatus according to the present invention is not limited to paper 510. In addition to paper, the medium may be made of various materials such as fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc., as long as it can be wound around a core. The form of the medium is also not limited to a long object, and may be a medium cut to a predetermined size.

[0018] Also, the printing device 500 is exemplified as a so-called line type device configuration in which the paper 510 is moved relative to the inkjet recording unit 550 at a fixed position and an image is formed on the paper 510, but is not limited to the line type. Any configuration may be used as long as the inkjet recording unit 550 and the paper 510 are moved relative to each other. Therefore, for example, a so-called serial type device configuration may be used in which the inkjet recording unit 550 is moved in a direction perpendicular to the paper feed direction relative to the paper 510 that is fed intermittently and an image is formed on the paper 510. Alternatively, a so-called flatbed type device configuration may be used in which the inkjet recording unit 550 is moved in the XY directions relative to the paper 510 held on a paper placement table and an image is formed on the paper 510.

[0019] Examples of the ejected material used in the inkjet recording unit 550 include solutions, suspensions, and emulsions containing solvents such as water and organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium, and edible materials such as natural dyes. The liquid may also contain fine powders such as metal powders. These can be used for applications such as inkjet inks, paints for coating, surface treatment liquids, liquids for forming components of electronic elements and light-emitting elements, and electronic circuit resist patterns, and material liquids for three-dimensional modeling.

[0020] In the printing device 500 having the above configuration, the medium support shaft according to the present invention is applied to at least one of the paper feed section 501 and the paper discharge section 509 .

[0021] [Conventional media support shaft] FIG. 2 is a diagram illustrating a conventional example of a medium support shaft according to the present invention, which is a typical structural example for fixing paper 510, which is a roll medium.

[0022] 2, in order to rotatably support paper 510 in paper feeder 501, holding roller 511 needs to be inserted into and fixed to core member 5101, which is the core of paper 510. Note that holding roller 511 corresponds to an embodiment of a medium support shaft according to the present invention.

[0023] 2(a), the holding roller 511 has a rotation gear 5111 for connecting to a transport control unit included in the paper feed unit 501. The rotation gear 5111, which serves as a support shaft holding unit, connects to a drive mechanism of the transport control unit, thereby rotating the holding roller 511 and rotating the paper 510 in the sending direction.

[0024] As shown in FIG. 2(b), the paper 510 is fixed to the holding roller 511 as a medium support shaft by an expansion portion 5112. The expansion portion 5112 is provided on the outer periphery of the holding roller 511, and expands when gas is injected into the expansion portion 5112, expanding to a position outside the outer diameter of the holding roller 511. When the expansion portion 5112 expands, the expansion portion 5112 is pressed against the inner wall of the core member 5101. In this pressed state, the paper 510 is fixed to the holding roller 511. When a driving force is transmitted to the holding roller 511 via the rotation gear 5111 in the pressed state, the paper 510 rotates.

[0025] Next, a problem with the typical example structure for fixing paper 510 shown in Fig. 2 will be described with reference to Fig. 3. When removing paper 510 fixed to paper feeder 501, it is necessary to release the gas from expanded expansion section 5112 to cause it to contract and release the pressure contact state with core member 5101 to a non-pressure contact state. In the non-contact state, the outer circumferential surface (outer axial surface) of holding roller 511 becomes capable of contacting the inner wall of core member 5101.

[0026] Assume that the holding roller 511 is moved in the axial direction relative to the core member 5101 with the outer circumferential surface of the holding roller 511 in contact with the inner wall of the core member 5101. If the holding roller 511 is repeatedly inserted and removed from the core member 5101 as in this situation, the holding roller 511 scrapes the inner wall at the contact portion between the holding roller 511 and the core member 5101, and a pile 5119 of scrapes accumulates at the installation position of the contracting expansion section 5112. This accumulation increases the resistance when removing the holding roller 511 from the core member 5101, which may increase the work time required to remove the paper 510.

[0027] [Embodiment of the media support shaft] Next, a characteristic structure of the medium support shaft according to the present invention will be described with reference to Fig. 4. Holding roller 511 as an embodiment of the medium support shaft has rotating member 5115 as an inner wall contact portion. Rotating member 5115 is provided at a plurality of locations on the outer circumferential surface of holding roller 511. For example, as illustrated in Fig. 4(a), rotating member 5115 is provided near the center of holding roller 511 in the longitudinal direction and near both ends in the longitudinal direction.

[0028] The rotating member 5115 has an arc-shaped portion that comes into contact with the inner wall of the core member 5101 in the axial direction of the holding roller 511, which is the relative movement direction when the holding roller 511 is attached to or detached from the core member 5101. For example, the rotating member 5115 is a spherical member that rotates while coming into contact with the winding core of the core member 5101 in the axial direction of the holding roller 511.

[0029] That is, the rotating member 5115 reduces the contact area between the holding roller 511 and the core member 5101 and reduces the resistance, thereby reducing the load when attaching the holding roller 511 to the core member 5101.

[0030] 4(c), the rotating member 5115 has a diameter smaller than the height from the outer circumferential surface of the holding roller 511 when the expanding portion 5112 expands to fix the core member 5101. Therefore, the action of fixing the core member 5101 when the expanding portion 5112 expands is not affected.

[0031] In addition, when the rotating member 5115 is not expanded, in which the gas in the expansion portion 5112 is discharged and the expansion portion 5112 is contracted, if the expansion portion 5112 is recessed inwardly toward the outer circumferential surface of the retaining roller 511, the rotating member 5115 will come into contact with the inner wall of the core member 5101, as illustrated in Figure 4(b).

[0032] As described above, the holding roller 511 according to this embodiment reduces frictional resistance when it is removed from the core member 5101, and can prevent the inner wall of the core member 5101 from being scraped when the holding roller 511 is inserted or removed.

[0033] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical gist of the present invention. The present invention covers all technical matters included in the technical ideas described in the claims. The above-described embodiments are preferred examples, but a person skilled in the art can realize various modifications from the disclosed contents. Such modifications are also included in the technical scope described in the claims.

[0034] For example, aspects of the present invention are as follows. <1> A medium support shaft fixed to a roll medium formed by winding a sheet-like medium around a core member, a fixing portion provided on the outer circumferential surface, which is in a pressed state against the inner wall of the core member when gas is injected and expands, and which is in a non-pressurized state not in contact with the inner wall when the gas is discharged and contracts; an inner wall contact portion provided on an outer circumferential surface of the shaft, the inner wall contact portion being in contact with the inner wall in the non-pressure-contact state and not in contact with the inner wall in the pressurized state; The medium support shaft is characterized by comprising: <2> The inner wall contact portion has an arc-shaped portion that contacts the inner wall. The above <1> 2 is a medium support shaft according to the first embodiment. <3> The inner wall contact portion is a spherical member that is rotatable in a relative movement direction when being removed from the core member. The above <1> or <2> 2 is a medium support shaft according to the first embodiment. <4> The inner wall contact portion is provided at a plurality of locations in the axial direction. The above <1> ~ <3> 13. The medium support shaft according to claim 12, wherein <5> a medium support shaft fixed to a roll medium formed by winding a sheet-like medium around a core member; a support shaft holder that rotatably holds the medium support shaft; a medium delivery unit that rotates the medium support shaft to deliver the medium; Equipped with The medium support shaft <1> ~ <4> The medium support shaft according to any one of claims 1 to 5, The medium transport device is characterized in that <6> a medium delivery unit that delivers the roll medium; an image forming unit that forms an image on the roll medium sent out from the medium sending unit; a medium winding section that winds up the roll medium on which an image is formed; An image forming apparatus having At least one of the medium delivery section and the medium take-up section has a medium support shaft that rotatably supports the roll medium. <1> ~ <4> The medium support shaft according to any one of claims 1 to 5, The image forming apparatus is characterized in that [Explanation of symbols]

[0035] 500:Printing device 501:Paper feed section 510: Paper 5101: Core material 5111: Rotating gear 5112: Expansion section 5115 : Rotating parts [Prior art documents] [Patent documents]

[0036] [Patent Document 1] JP 2005-089168 A

Claims

1. A medium support shaft fixed to a roll medium formed by winding a sheet-like medium around a core member, a fixing portion that comes into a pressure contact state with the inner wall of the core member when gas is injected and inflated, and comes into a non-pressure contact state where it does not contact the inner wall when the gas is discharged and contracted; an inner wall contact portion provided on the outer peripheral surface of the shaft so as to contact the inner wall in the non-pressure contact state and not contact the inner wall in the pressure contact state; The medium support shaft is characterized by comprising the above.

2. The inner wall contact portion is such that the portion in contact with the inner wall is arc-shaped, The medium support shaft according to Claim 1.

3. The inner wall contact portion is a spherical member that is rotatable in the relative movement direction when being withdrawn from the core member, The medium support shaft according to Claim 1.

4. The inner wall contact portion is provided at a plurality of locations in the axial direction, The medium support shaft according to Claim 1.

5. A medium support shaft fixed to a roll medium formed by winding a sheet-like medium around a core member, a support shaft holding portion that rotatably holds the medium support shaft, a medium sending portion that rotates the medium support shaft to send out the medium; comprising, the medium support shaft is the medium support shaft according to any one of Claims 1 to 4, The medium conveyance device is characterized by the above.

6. A medium sending portion that sends out a roll medium, an image forming portion that forms an image on the roll medium sent out from the medium sending portion, a medium winding portion that winds up the roll medium on which the image is formed; An image forming apparatus having, at least, the medium support shaft that rotatably supports the roll medium in either the medium sending portion or the medium winding portion is the medium support shaft according to any one of Claims 1 to 4, The image forming apparatus is characterized by the above.

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