Image forming device

Abstract

To provide an image forming device that does not interfere with a conveyance of a recording medium even when the continuous book-shaped recording medium is conveyed by using a suction part, and has good adhesion between the recording medium and a conveyance member.SOLUTION: An image forming device includes an image forming part 10, a rotatable hollow drum-shaped conveyance member 12 that conveys a continuous book-shaped recording medium 2, and a suction part 14 arranged inside the conveyance member 12 and sucking the recording medium 2 through the conveyance member 12. A region sucked by the suction part 14 is fixed to the region where the recording medium 2 and the conveyance member 12 come into contact with each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] Inkjet recording devices are known that form images by fixing a recording medium such as paper to a transport drum and ejecting ink from a recording head disposed close to the outer circumferential surface of the transport drum onto the recording medium. Such inkjet recording devices are required to achieve both high productivity and reduced damage to the recording medium during drying.

[0003] Conventionally, hot air or infrared heaters have been used to dry images on recording media, but the recording media is damaged during drying. In response to this, a temperature-controllable transport drum is used and the recording media is wrapped around the transport drum, reducing damage to the recording media during drying.

[0004] However, when the recording medium is transported at high speed, air gets in between the recording medium and the transport drum, reducing the adhesion between the recording medium and the transport drum, which causes damage to the recording medium. In response to this, it is thought that the adhesion between the recording medium and the transport drum can be improved by using the air knife method, but if the transport speed exceeds 30 m / min, air gets caught and sufficient adhesion cannot be obtained.

[0005] Patent Document 1 discloses a sheet material transport unit that includes a drum-shaped transport body having an air suction path and a suction member (suction plate) that has a plurality of suction holes and is attached so as to be wrapped around the surface of the transport body and that adsorbs the sheet material so that it conforms to the surface shape of the transport body, with the aim of suppressing floating of the recording medium with high precision. In Patent Document 1, the suction plate rotates together with the transport body and transports the recording medium while sucking it. Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, the suction plate rotates on the transport drum along with the transport of the recording medium, which results in some areas of the recording medium being suctioned and some areas not being suctioned. Therefore, when transporting a continuous sheet, the transport is hindered, making it difficult to transport at high speed. In addition, when some areas of the recording medium are suctioned and some are not suctioned, there is a problem that the adhesion between the transport drum and the recording medium cannot be sufficiently ensured.

[0007] Therefore, an object of the present invention is to provide an image forming device that does not hinder the transport of a continuous sheet of recording medium, even when using a suction section to transport the recording medium, and has good adhesion between the recording medium and the transport member. [Means for solving the problem]

[0008] In order to solve the above problems, the image forming apparatus of the present invention is an image forming apparatus having an image forming unit, a rotatable hollow drum-shaped transport member that transports a continuous recording medium, and a suction unit that is disposed inside the transport member and sucks the recording medium through the transport member, the conveying member is made of a porous material, the average pore size of the porous material is 5 μm or more and 30 μm or less, and the conveying speed of the recording medium is 30 m / min or more; The suction area of ​​the suction unit is fixed to a region where the recording medium and the transport member contact each other, and the suction unit is disposed at a portion of the transport member in the rotation direction. Effect of the Invention

[0009] According to the present invention, an image forming device can be provided in which the transport of the recording medium is not hindered even when a continuous sheet of recording medium is transported using a suction section, and which has good adhesion between the recording medium and the transport member. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. [Diagram 2] 1 is a schematic diagram showing a main part of an example of an image forming apparatus according to the present invention; [Diagram 3] FIG. 3 is a schematic cross-sectional view of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The image forming apparatus according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiment, and can be modified within the scope of what a person skilled in the art can imagine, such as other embodiments, additions, modifications, deletions, etc., and any aspect is included in the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0012] The image forming apparatus of the present invention is an image forming apparatus having an image forming unit, a rotatable hollow drum-shaped transport member that transports a continuous recording medium, and a suction unit that is arranged inside the transport member and sucks the recording medium through the transport member, and is characterized in that the area that is sucked by the suction unit is fixed to the area where the recording medium and the transport member come into contact.

[0013] An embodiment of the image forming apparatus of the present invention will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a general schematic diagram of the image forming apparatus of this embodiment, Fig. 2 is a schematic cross-sectional diagram of the main part of the apparatus, and Fig. 3 is a cross-sectional diagram taken along line AA in Fig. 2.

[0014] FIG. 1 shows a recording medium 2, an image forming section 10, a transport member 12, a suction section 14, a heating section 16, a drying section 18, and transport rollers 21 and 22.

[0015] The recording medium 2 is conveyed in the direction of the arrow in the figure by conveying rollers 21, 22 and a conveying member 12. The recording medium 2 is a continuous recording medium, and is also called a substrate, continuous sheet, etc. The material of the recording medium 2 can be changed as appropriate, and for example, paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc. can be used.

[0016] For example, an inkjet head (also referred to as a recording head) can be used as the image forming unit 10. In this embodiment, the image forming unit 10 is disposed upstream of a region where a conveying member 12 and the recording medium 2 come into contact with each other in the conveying direction of the recording medium 2.

[0017] The image forming unit 10 forms an image by applying or ejecting a recording liquid (also referred to as ink) onto the surface of the recording medium 2. The ink used can be changed as appropriate, and may be one type or multiple types.

[0018] The transport member 12 is a rotatable hollow drum-shaped member, and while rotating, transports the recording medium 2. Hereinafter, the drum-shaped transport member may be referred to as a transport drum.

[0019] The transport member 12 can be appropriately selected, and may be, for example, a porous material, as long as the suction unit 14 can suck the recording medium 2 through the transport member 12. By using a porous material, the suction unit 14 can easily perform suction, and the adhesion between the recording medium 2 and the transport member 12 can be further improved.

[0020] When using a porous material, it is preferable that the holes of the porous material are of an appropriate size. If the holes are too large, the recording medium 2 may conform to the shape of the holes, causing damage to the recording medium 2. If the holes are too small, resistance during suction becomes large, and sufficient suction force may not be ensured. From this perspective, it is preferable that the average size of the holes of the porous material is 5 μm to 30 μm.

[0021] The suction unit 14 is disposed inside the transport member 12 and sucks the recording medium 2 through the transport member 12. The recording medium 2 is transported by the transport member 12 rotating in the direction of the arrow in the figure while the suction unit 14 sucks the recording medium 2. The suction unit 14 performs suction from the circumference of the transport member 12 toward the center, thereby improving the adhesion between the recording medium 2 and the transport member 12.

[0022] If the suction unit 14 is not used, the adhesion between the transport member 12 and the recording medium 2 cannot be ensured, and air gets in between the transport member 12 and the recording medium 2, causing air bubbles. If the transport member 12 and the recording medium 2 are in good adhesion, even when the recording medium 2 is dried by the drying unit 18, the heat applied to the recording medium 2 is transferred to the transport member 12, and a sudden rise in temperature can be prevented. However, if drying is performed by the drying unit 18 with air remaining between the transport member 12 and the recording medium 2, heat does not transfer to the transport member 12 in the part where the air has entered (the part where the air bubbles have occurred), and the temperature rises suddenly, causing damage to the recording medium.

[0023] In addition, the conventional air knife method presses the recording medium from above with air, making it difficult to remove air bubbles other than at the boundary where contact begins between the conveying member 12 and the recording medium 2. Furthermore, when the conveying speed of the recording medium is high, it becomes difficult to ensure close contact between the recording medium 2 and the conveying member 12 even when the air knife method is used.

[0024] In contrast, in this embodiment, the suction unit 14 is disposed inside the transport member 12, and the recording medium 2 is sucked through the transport member 12, thereby ensuring close contact between the transport member 12 and the recording medium 2. This makes it possible to prevent air from entering between the transport member 12 and the recording medium 2. Even if air does enter when the transport member 12 and the recording medium 2 come into contact with each other, the suction unit 14 can be used to remove the air that has entered between them.

[0025] As a result, in this embodiment, even when a drying section is used, or even in the case of high-speed transport in which air bubbles would be generated using the conventional air knife method, it is possible to improve the adhesion between the recording medium 2 and the transport member 12, and to suppress damage to the recording medium.

[0026] In this embodiment, the area where the suction unit 14 performs suction is fixed to the area where the recording medium 2 and the transport member 12 come into contact. As shown in Fig. 1, in this embodiment, the suction unit 14 is disposed in a part of the direction of rotation of the transport member 12, so that the recording medium 2 can be sucked in the fixed area of ​​the transport member 12. This makes it possible to avoid suction in the area where the recording medium 2 and the transport member 12 do not come into contact, and prevents the transport of the continuous recording medium 2 from being hindered.

[0027] On the other hand, in the conventional technology in which the suction unit rotates together with the transport member (transport drum), there are some areas of the recording medium that are suctioned and some that are not suctioned. Therefore, when transporting a continuous sheet, the suction force cannot be secured as the suction plate rotates, and the adhesion between the transport drum and the recording medium cannot be secured sufficiently.

[0028] In this embodiment, as described above, the suction unit 14 is disposed in a portion of the conveying member 12 in the rotational direction, so that it is possible to avoid suctioning the area where the recording medium 2 does not come into contact with the conveying member 12. This makes it possible to prevent the conveyance of the recording medium 2 from being impeded.

[0029] As another example, it is also possible to change the suction force of the suction unit 14 depending on the location. In this case, the suction force in the area where the recording medium 2 and the conveying member 12 do not contact each other is made lower than the suction force in the area where the recording medium 2 and the conveying member 12 contact each other. This also makes it possible to prevent the conveyance of the continuous recording medium 2 from being hindered.

[0030] The suction unit 14 can be appropriately selected, and can have a configuration as shown in Fig. 3. The suction unit 14 in this example has a base material 14a and a suction device 14c, which are fixedly arranged on the device. The broken line in the figure indicates the rotation axis of the conveying member 12.

[0031] The base material 14a has a suction path 14b, and when the suction device 14c performs suction, the sucked air flows through the suction path 14b. As a result, the recording medium 2 on the conveying member 12 is sucked, and the recording medium 2 is brought into close contact with the surface of the conveying member 12.

[0032] As the suction device 14c, for example, a blower or the like can be used. The suction device 14c is arranged, for example, fixed to the side surface of the conveying member 12. In this example, the suction device 14c is arranged on both side surfaces of the conveying member 12, but is not limited to this and may be arranged on one side surface.

[0033] As shown in the figure, the image forming apparatus of this embodiment has a heating section 16 inside the transport member 12. The heating section 16 heats the transport member 12. The heating section 16 may directly heat the transport member 12, or may heat the transport member 12 via a suction section 14, for example, a base material 14a or a suction path 14b formed in the base material 14a.

[0034] By using the heating unit 16, the transport member 12 can be efficiently heated, and the temperature of the heating member 12 can be adjusted to maintain a constant temperature. If the temperature of the heating member 12 is maintained constant, the temperature difference between the front and back of the recording medium 2 can be reduced when the recording medium 2 is heated by the drying unit 18, and damage to the recording medium 2 can be reduced.

[0035] The heating unit 16 can be appropriately selected, and for example, a hot water heating device, a dielectric heating device, or the like can be used.

[0036] The image forming apparatus of this embodiment has a drying unit 18 that heats and dries the recording medium 2 and the ink on the recording medium 2. The drying unit 18 in this example is disposed at a position facing the transport member 12. When heating the ink on the recording medium 2, the drying unit 18 is disposed downstream of the image forming unit 10 in the transport direction of the recording medium 2.

[0037] The drying section 18 can be appropriately selected, and for example, an infrared heater, a hot air generator, etc. can be used. In the example shown in Fig. 1, a hot air generator is used as the drying section 18. The arrangement, number, etc. of the drying section 18 are not particularly limited and can be changed appropriately.

[0038] When an infrared heater is used as the drying unit 18, it is preferable that the surface temperature of the heater is 500° C. or higher. In an image forming apparatus having an image forming unit and a drying unit, a higher drying temperature allows the recording medium and the ink on the recording medium to be dried more satisfactorily. On the other hand, when the drying temperature is high, damage to the recording medium occurs if the adhesion between the recording medium and the conveying member is not ensured.

[0039] In contrast to this, in this embodiment, since the adhesion between the recording medium and the conveying member can be increased as described above, damage to the recording medium can be reduced even when the drying temperature is high, for example, when the heater surface temperature is set to 500° C. or higher. Therefore, according to this embodiment, even when the drying temperature of the infrared heater is set to a high temperature, damage to the recording medium can be reduced and good drying can be performed.

[0040] When a hot air generator is used as the drying unit 18, it is preferable that the temperature of the hot air is 100° C. or higher. For the same reasons as above, according to this embodiment, even when the drying temperature of the hot air generator is high, for example, the temperature of the hot air is 100° C. or higher, damage to the recording medium can be reduced and good drying can be performed.

[0041] When a hot air generator is used as the drying unit 18, the hot air preferably has a wind speed of 10 m / sec or more. In an image forming apparatus using a hot air generator as the drying unit, a faster hot air speed can dry the recording medium and the ink on the recording medium better. On the other hand, when the hot air speed is fast, the recording medium may be damaged if the adhesion between the recording medium and the transport member is not ensured.

[0042] In contrast, in this embodiment, since the adhesion between the recording medium and the conveying member can be increased as described above, damage to the recording medium can be reduced even when the hot air speed is high, for example, even when the hot air speed is 10 m / sec or higher. Therefore, according to this embodiment, even when the hot air speed of the hot air generator is high, damage to the recording medium can be reduced and good drying can be performed.

[0043] The transport speed of the recording medium 2 can be changed as appropriate, and is preferably, for example, 30 m / min or more. In an image forming apparatus using a transport drum, an air knife method may be used to improve the adhesion between the transport drum and the recording medium. However, as described in, for example, JP-A-2004-255720, when the transport speed of the recording medium is slow, the air knife method can improve the adhesion between the transport drum and the recording medium, but when the transport speed of the recording medium is fast, the adhesion may not be improved. When the transport speed of the recording medium is high, for example, 30 m / min or more, air is entrained even if the air knife method is used, and the adhesion between the transport drum and the recording medium cannot be improved.

[0044] In contrast, in this embodiment, since the adhesion between the recording medium and the conveying member can be increased as described above, it is possible to suppress the entrainment of air even when the conveying speed of the recording medium is high, for example, at 30 m / min or higher. Therefore, even when the conveying speed of the recording medium is increased, good adhesion can be maintained, and productivity can be improved. [Explanation of symbols]

[0045] 2 Recording media 10 Image forming section 12 Transporting member 14 Suction part 14a Base material 14b Suction Path 14c suction device 16 Heating section 18 Drying section 21, 22 Conveyor roller [Prior art documents] [Patent documents]

[0046] [Patent Document 1] JP 2017-226491 A

Claims

1. An image forming unit; A rotatable hollow drum-shaped conveying member for conveying a continuous recording medium; a suction unit that is disposed inside the transport member and that sucks the recording medium through the transport member, The transport member is made of a porous material, and the average pore size of the porous material is 5 μm or more and 30 μm or less. The conveying speed of the recording medium is 30 m / min or more, a region where the suction unit suctions is fixed to a region where the recording medium and the conveying member come into contact with each other; The image forming apparatus according to claim 1, wherein the suction portion is disposed at a portion of the conveying member in a rotation direction.

2. 2 . The image forming apparatus according to claim 1 , wherein the suction section does not perform suction in an area where the recording medium does not contact the transport member, or performs suction with a lower force than in an area where the recording medium contacts the transport member.

3. 3. The image forming apparatus according to claim 1, further comprising a heating section disposed inside the conveying member.

4. the image forming unit is disposed upstream of a region where the conveying member contacts the recording medium in a conveying direction of the recording medium, 4. The image forming apparatus according to claim 1, further comprising a drying unit disposed downstream of the image forming unit in the transport direction of the recording medium and facing the transport member.

5. 5. The image forming apparatus according to claim 4, wherein the drying section is an infrared heater, and the surface temperature of the heater is 500[deg.] C. or higher.

6. 5. The image forming apparatus according to claim 4, wherein the drying section is a hot air generating device, and the temperature of the hot air is 100[deg.] C. or higher.

7. 5. The image forming apparatus according to claim 4, wherein the drying section is a hot air generating device, and the hot air has a wind speed of 10 m / sec or more.

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