Patent Application
20150336406
The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2014-104211, filed May 20, 2014. The contents of this application are incorporated herein by reference in their entirety.
The present disclosure relates to conveyor devices and inkjet recording apparatuses.
An inkjet recording apparatus conveys a sheet of paper as a recording medium such as copy paper using a conveyor belt and a feed member included therein. The feed member includes a paper feed roller, a conveyance roller, a sheet guide, etc. Recording heads forms an image on a sheet by ejecting ink droplets toward the sheet conveyed. In order to reduce degradation of image quality that may be caused due to sheet flexure or sheet lift up from the conveyor belt in the course of sheet conveyance, an inkjet recording apparatus has been developed that includes a conveyor belt through which suction holes are perforated and a suction section that sucks on a sheet through the conveyor belt.
In an inkjet recording apparatus having such a configuration, paper dust is generated by contact between a sheet and the feed member in the course of conveyance to be attached to the sheet. When such a sheet to which paper dust is attached is conveyed along a conveyance path to the conveyor belt, air flow through the conveyor belt may separate and stir up the paper dust from the sheet to cause the paper dust to be attached to nozzles.
In order to reduce separation and stirring up of paper dust from a sheet over the conveyor belt and attachment thereof to the nozzles, a certain liquid ejection device is provided that causes paper dust attached to a sheet to separate from the sheet by blowing air to the sheet in an area upstream of the nozzles in the conveyance path.
A conveyor device according to the present disclosure includes a feed member, a conveyance belt, and a suction section. The feed member feeds a recording medium while in contact with a part of the recording medium. The conveyor belt conveys the recording medium having been fed by the feed member. The suction section sucks the recording medium onto the conveyance belt. The conveyor belt includes a first region that is to receive the part of the recording medium and a second region adjacent to the first region. The conveyor belt has a plurality of suction holes in communication with the suction section. The suction holes have a lower opening ratio in the first region lower than in the second region.
An inkjet recording apparatus according to the present disclosure includes the above conveyor device and an inkjet head. The inkjet head is located opposite to the conveyor device.
Embodiments of an conveyor device and an inkjet recording apparatus according to the present disclosure will be described below with reference to the accompanying drawings. Note that in the figures of the accompanying drawings, the like reference numerals refer to same or corresponding elements, and description thereof is not repeated.
The basic principle of a conveyor device according to a first embodiment of the present disclosure will be described with reference to
The inkjet recording apparatus 1 includes a conveyor device 300 and recording heads 390. The conveyor device 300 is located opposite to the recording heads 390.
The conveyor device 300 includes an endless conveyor belt 355 and a suction section 360. The conveyor belt 355 conveys a recording medium P. The suction section 360 sucks on the recording medium P through the conveyor belt 355. The suction section 360 includes a guide member 361. The guide member 361 supports the recording medium P with the conveyor belt 355 therebetween.
With reference to
The paper feed section 20 includes a paper feed cassette 200. The paper feed cassette 200 is freely detachable from the apparatus housing 10. The paper feed cassette 200 contains a plurality of recording media P in a stacked state. The recording media P may be paper like plain paper, recycled paper, thin paper, or thick paper, for example.
The image forming section 30 includes the conveyor device 300 and the recording heads 390. The conveyor device 300 includes a first paper conveyance section 310 and a second paper conveyance section 350 located opposite to the recording heads 390. The second paper conveyance section 350 is located between the first paper conveyance section 310 and the paper ejecting section 40. Note that the image forming section 30 may also include a drying device (not illustrated). The drying device dries ink droplet having ejected on a recording medium P.
The first paper conveyance section 310 has a paper conveyance path 311 that is roughly C-shaped. The first paper conveyance section 310 includes a paper feed roller 312, a first pair of conveyance rollers 313, a second pair of conveyance rollers 314, a pair of registration roller, and guide plates 316. The paper feed roller 312 is located above one end of the paper feed cassette 200. The first pair of conveyance rollers 313 is located at an input end of the paper conveyance path 311. The second pair of conveyance rollers 314 is located midway in the paper conveyance path 311. The pair of registration rollers 315 is located at an output end of the paper conveyance path 311.
The guide plates 316 are located between the paper feed roller 312 and the first pair of conveyance rollers 313. The paper feed roller 312 picks up the recording media P contained in the paper feed cassette 200 one at a time. The guide plates 316 guide the recording medium P picked up by the paper feed roller 312 to the first pair of conveyance rollers 313.
Referring to
The first pair of conveyance rollers 313 sandwiches the recording medium P guided by the guide plates 316 and feeds it to the paper conveyance path 311. A specific process is as follows. The first pair of conveyance rollers 313 includes a feed roller 313a and a retard roller 313b. The feed roller 313a and the retard roller 313b are located opposite to and in press contact with each other. The feed roller 313a rotates to feed the recording medium P in the conveyance direction D. Upon receiving a single recording medium P, the retard roller 313b follows the rotation of the feed roller 313a to be rotated. By contrast, upon receiving a plurality of recording media P in layers, the retard roller 313b rotates in a direction inverse to a direction in which the recording media P is fed, or stops for separating a recording medium P in contact with the feed roller 313a from the other recording medium or media P. As a result, the single recording medium P can be fed by the feed roller 313a.
The second pair of conveyance rollers 314 sandwiches the recording medium P having been fed by the first pair of conveyance rollers 313 and conveys it to the pair of registration rollers 315. The pair of registration rollers 315 performs skew correction on the recording medium P that has abutted on and stops at the pair of registration rollers 315. The pair of registration rollers 315 then temporarily holds the recording medium P in order to synchronize conveyance of the recording medium P with a timing at which printing is to be performed on the recording medium P. The pair of registration rollers 315 subsequently feeds the recording medium P to the second paper conveyance section 350 in accordance with the timing of printing on the recording medium P.
The second paper conveyance section 350 includes a speed detection roller 351, a sheet holding roller 352, a drive roller 353, a tension roller 354, a pair of guide rollers 356, the endless conveyor belt 355, and a suction section 360. The conveyor belt 355 is wound around the speed detection roller 351, the drive roller 353, the tension roller 354, and the pair of guide rollers 356. In the present specification, a surface of the conveyor belt 355 on which a recording medium P is to be loaded is referred to as a conveyance surface and a surface thereof opposite to the conveyance surface is referred to as a conveyance reverse surface. The rotation axis of each of the rollers including the drive roller 353 is arranged in parallel to the X axis. The conveyor belt 355 has a plurality of suction holes. Each of the suction holes passes from the conveyance surface to the conveyance reverse surface through the conveyor belt 355.
The speed detection roller 351 is located upstream of the guide member 361 in terms of the conveyance direction D of the recording medium P. The speed detection roller 351 includes a pulse plate not illustrated. The speed detection roller 351 is rotated by being in contact with the conveyor belt 355 that circulates. The circulation speed of the conveyor belt 355 is detected by measuring the rotational speed of the pulse plate that is rotated solidly with the speed detection roller 351. The speed detection roller 351 reduces influence of meandering correction on the conveyor belt 355 under the recording heads 390.
The sheet holding roller 352 is located at an upstream end of the guide member 361 in terms of the conveyance direction D with the conveyor belt 355 therebetween. The sheet holding roller 352 conveys the recording medium P in the conveyance direction D while pressing the recording medium P against the conveyor belt 355 and the guide member 361. The sheet holding roller 352 reduces curling of the recording medium P so that the suction section 360 sucks on and holds of the recording medium P entirely uniformly. The configuration as above can allow the recording medium P to be held on the conveyor belt 355 in a secured manner. In order to reduce vibration of the sheet holding roller 352 that may be caused due to collision of the recording medium P with the sheet holding roller 352 at arrival of the recording medium P at the sheet holding roller 352, it is preferable that the moment of inertia of the sheet holding roller 352 is small and the sheet holding roller 352 is light. For example, the sheet holding roller 352 may be an aluminum hollow pipe or a hollow pipe with a plurality of ribs. In a configuration in which the surface layer of the sheet holding roller 352 is made from aluminum, the surface of the sheet holding roller 352 may be anodized in order to prevent abrasion. Being anodized herein means formation of an aluminum oxide film by electrolysis of aluminum as an anode in an acid treatment bath for electrochemical oxidation on the surface of the aluminum Note that anodization makes the sheet holding roller 352 electrically insulated. However, in a situation in which the sheet holding roller 352 should be conductive, the surface of the sheet holding roller 352 is not anodized.
The speed of the recording medium P conveyed by the pair of registration rollers 315 may differ from the speed thereof conveyed by the conveyor belt 355 in some situations. However, such difference can be reduced in a manner that the sheet holding roller 352 applies pressing force to the recording medium P on the conveyor belt 355 to cause the recording medium P to flex between the pair of registration rollers 315 and the sheet holding roller 352.
The drive roller 353 is spaced apart from the speed detection roller 351 in terms of the conveyance direction D of the recording medium P. The speed detection roller 351 and the drive roller 353 keep the conveyor belt 355 on the guide member 361 flat. The drive roller 353 is in close contact with the conveyor belt 355 by friction force. For example, in a configuration in which the conveyor belt 355 is made from a resinous material such as polyimide (PI), polyamidimide (PAI), polyvinylidene fluoride (PVDF), or polycarbonate (PC), a surface layer of the drive roller 353 is preferably made from a rubber material such as ethylene propylene diene (EPDM) rubber, polyurethane resin, or nitrile rubber (NBR). In a configuration in which the image forming section 30 forms an image on the recording medium P using an aqueous ink, EPDM rubber is preferably used as a material of the surface layer of the drive roller 353 in order to prevent swelling of the rubber material.
In a configuration in which the conveyor belt 355 is made from a rubber material such as EPDM, the surface layer of the drive roller 353 may be made from a metal. In a configuration in which the surface layer of the drive roller 353 is made from aluminum, the surface of the drive roller 353 may be anodized in order to prevent abrasion. Anodization makes the drive roller 353 electrically insulated. However, in a situation in which the drive roller 353 should be conductive, the surface of the drive roller 353 is not anodized. Note that in a configuration in which the drive roller 353 are electrically conducted to the conveyor belt 355, electric grounding of the conveyor belt 355 can prevent reduction in accuracy of ink trajectory. In the configuration as above, the rubber material forming the conveyor belt 355 is made conductive.
The drive roller 353 is driven to be rotated by a motor (not illustrated) to circulate the conveyor belt 355 in the anticlockwise direction. In a situation in which unevenness in circulation speed of the conveyor belt 355 occurs, correction of the unevenness may be performed on the conveyor belt 355. The correction of the unevenness means to correct unevenness of the speed of the conveyor belt 355 to keep the conveyor belt 355 circulating at a constant speed. In a configuration in which unevenness of speed of the conveyor belt 355 is corrected, the drive roller 353 preferably has a low moment of inertia and is light. For example, the drive roller 353 may be a hollow pipe such as an aluminum pipe or a hollow pipe with a plurality of ribs. By contrast, in a configuration in which unevenness of speed of the conveyor belt 355 is not corrected, the drive roller 353 is preferably heavy in order to stabilize rotation of the drive roller 353 through a flywheel effect. In the configuration as above, the drive roller 353 is made from a material such as solid metal.
The tension roller 354 is located at an upstream end of the guide member 361 in the interior of the conveyor belt 355. The tension roller 354 applies tensile force to the conveyor belt 355 in order to ensure that the conveyor belt from does not sag. By changing orientation of one of the end portions of the tension roller 354, meandering of the conveyor belt 355 can be corrected in a self-regulating manner.
The conveyor belt 355 conveys the recording medium P held on the conveyor belt 355. The conveyor belt 355 is preferably made from polyamidimide (PAI) or polyimide (PI), for example. Use of such a material can reduce unevenness in thickness of the conveyor belt 355. The pair of guide rollers 356 is located below the suction section 360.
The pair of guide roller 356 is secured in place such as to confine a space surrounded by the inner peripheral surface (conveyance reverse surface) of the conveyor belt 355. A guide roller 356 of the pair of guide rollers 356 that is closer to the drive roller 353 keeps the amount of winding of the conveyor belt 355 to the drive roller 353 constant. The other guide roller 356 that is closer to the tension roller 354 keeps the amount of winding of the conveyor belt 355 to the tension roller 354 constant for stable meandering correction on the conveyor belt 355.
The suction section 360 is located on the side of the conveyance reverse surface of the conveyor belt 355 such as to be opposite to the recording heads 390 with the conveyor belt 355 therebetween. The suction section 360 includes the guide member 361, an air flow chamber 362, and at least one sucking device 363.
The air flow chamber 362 is a hollow casing having an open top end. In other words, the upper portion of the air flow chamber 362 has an opening. The guide member 361 covers (blocks) the upper opening of the air flow chamber 362. The guide member 361 supports the recording medium P through the conveyor belt 355.
The sucking device 363 is disposed in communication with the air flow chamber 362 and draws air in the air flow chamber 362 to create negative pressure in the air flow chamber 362. As a result, the recording medium P is sucked toward the top of the air flow chamber 362 through the conveyor belt 355 and the guide member 361. It should be noted here that negative pressure refers to pressure lower than reference pressure. The reference pressure referred to in the present specification is atmospheric pressure. Negative pressure “PN” is an absolute value of (PA−PR), wherein “PA” represents the absolute pressure and “PR” represents the reference pressure (PN=|PA−PR|). The absolute pressure is pressure based on the absolute vacuum of 0. The air flow chamber 362 functions as a decompression chamber.
The paper ejecting section 40 includes a conveyance guide 400, a pair of ejection rollers 410, and an exit tray 420. The conveyance guide 400 is located downstream of the second paper conveyance section 350 in terms of the conveyance direction D of the recording medium P. The exit tray 420 is fixed to the apparatus housing 10 and protrudes outward from an exit port 430 formed in the apparatus housing 10.
The conveyance guide 400 guides the recording medium P being conveyed from the conveyor belt 355 to the pair of ejection rollers 410. The recording medium P that has passed through the conveyance guide 400 is conveyed by the pair of ejection rollers 410 to the exit port 430 and ejected onto the exit tray 420 through the exit port 430.
The conveyor belt 355 will be described with reference to
As illustrated in
As illustrated in
Referring to
The feed member F includes the first pair of conveyance rollers 313, the second pair of conveyance rollers 314, and the paper feed roller 312. The recording medium P comes in contact with the feed member F in conveyance of the recording medium P in the conveyance direction D1. A part of the recording medium P that comes in contact with the feed member F will be referred to as a contact region.
With reference to
A region of the print surface of the recording medium P that comes in contact with the roller member 312a is referred to as a contact region 801. The contact region 801 illustrated in
A situation in which the feed roller 313a is in contact with the recording medium P will be described with reference to
The roller member 313a1 comes in contact with a right end part of the recording medium P in terms of the conveyance direction D1. The roller member 313a2 comes in contact with a left end part of the recording medium P in terms of the conveyance direction D1. Each of the roller members 313a1 and 313a2 has a width RW that is narrower than the width PW of the recording medium P. Accordingly, the roller members 313a1 and 313a2 come in contact with a contact region 802 of the recording medium P when feeding the recording medium P in the conveyance direction D1.
The contact region 802 includes a contact region 802a1 and a contact region 802a2. The contact region 801a1 is a region of the print surface of the recording medium P that comes in contact with the roller member 313a1. The contact region 802a1 is a region in the print surface of the recording medium P but may be a region in the print reverse surface thereof or each of them. The contact region 802a2 is a region of the print surface of the recording medium P that comes in contact with the roller member 313a2. The contact region 802a2 is a region in the print surface of the recording medium P but may be a region in the print reverse surface thereof or each of them. The contact region 802 (contact regions 802a1 and 802a2) is a region of the recording medium P extending in terms of the conveyance direction D1.
Note that the paper feed roller 312 includes only one roller member in
With reference to
As illustrate in
The region 701a is a region of the conveyance surface of the conveyor belt 355 that is to overlap with the contact region 801. The contact region 801 is a region of the recording medium P that is to come in contact with the roller member 312a, as described with reference to
The region 701b is a region of the conveyance surface of the conveyor belt 355 that is to overlap with the contact region 801a1. The contact region 802a1 is a region of the recording medium P that is to come in contact with the roller member 313a1, as described with reference to
The region 701c is a region of the conveyance surface of the conveyor belt 355 that is to overlap with the contact region 801a2. The contact region 802a2 is a region of the recording medium P that is to come in contact with the roller member 313a2, as described with reference to
The second region 702 is adjacent to the first region 701. The second region 702 includes regions 702a, 702b, 702c, and 702d. The second region 702 (regions 702a, 702b, 702c, and 702d) is a region of the conveyor belt 355 extending in terms of the conveyance direction D.
The conveyor belt 355 according to the first embodiment of the present disclosure will be described further in detail with reference to
The suction holes 355a have an opening ratio in the first region 701 lower than in the second region 702, as illustrated in
An opening ratio R can be obtained by Equation 1 below.
R=St/S (Equation 1):
wherein St is a total area of the openings of the suction holes 355a in a specific region, and S is a total area of the specific region. The opening ratio R is a ratio of the total area of the openings of the suction holes 355a in the specific region to the total area of the specific region.
In a configuration in which the diameters of the suction holes 355a are equal, St can be obtained by Equation 2 below.
St=Sa×N (Equation 2):
wherein Sa is an area of an opening of a suction hole 355a in a specific region, and N is the number of the suction holes 355a in the specific region. The total area of the openings of the suction holes 355a in the specific region is a total sum of the areas of the openings of the suction holes 355a in the specific region.
As described so far with reference to
With reference to
The conveyor belts 355 illustrated in
As illustrated in
In the present embodiment, each of the suction holes 355a in the first region 701 has a diameter of 1.5 mm. Also, the suction holes 355a in the second region 702 each have a diameter of 2 mm. Distances in the X and Y directions between adjacent suction holes 355a in both the first and second regions 701 and 702 are 8 mm and 8 mm, respectively. The suction holes 355a in the first and second regions 701 and 702 are arranged in a staggered formation in the X and Y directions indicated in each of the drawings.
As described with reference to
With reference to
The regions in the conveyor belts 355 illustrated in
As illustrated in
As described with reference to
With reference to
The regions in the conveyor belts 355 illustrated in
As illustrated in
As described with reference to
With reference to
Each of the conveyor belts 355 illustrated in
As described with reference to
As described with reference to
The third region 703 has no suction holes 355a in the conveyor belt 355 illustrated in
The third region 703 has no suction holes 355a in the conveyor belt 355 illustrated in
As described with reference to
Each of the conveyor belts 355 described with reference to
A conveyor belt 355 according to a sixth embodiment of the present disclosure will be described with reference to
The conveyor belt 355 includes a recording medium loading region 705 and a recording medium non-loading region 706. The recording medium loading region 705 is a region of the conveyance surface of the conveyor belt 355 that is to receive a recording medium P. The recording medium loading region 705 includes a first region 701 and a second region 702. The recording medium non-loading region 706 is adjacent to the recording medium loading region 705. The recording medium non-loading region 706 includes a region 706a and a region 706b.
The respective regions 706a and 706b are located on the respective opposite end portions in the X direction of the conveyor belt 355. The suction holes 355a may not be located in a part or entirety of the regions 706a and 706b.
Similarly to the conveyor belts 355 described with reference to
So far, the embodiments of the present disclosure have been described with reference to the drawings (
For example, the present disclosure is applicable to any combinations of two or more of the second to fourth embodiments. Specifically, in the present disclosure, the opening area of each of the suction holes 355a in a part of the first region 701 may be smaller than that of each of the suction holes 355a in the second region 702 (second embodiment) and the number of the suction holes 355a per unit area in a part of the first region 701 may be smaller than that of the suction holes 355a per unit area in the second region 702 (third embodiment).
Note that the suction holes 355a in the conveyor belt 355 are arranged in a staggered formation in the above embodiments but may be in a lattice pattern.
Further, the conveyor belt 355 has an endless shape in the above embodiments but may have a linear shape.
Any other variety of alterations may be made to the above embodiments within the scope not deviating from the subject matter of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-104211 | May 2014 | JP | national |
